DE102023136792A1 - CHARGING TECHNOLOGY FOR A SHOPPING CART - Google Patents

Abstract

The present invention relates to a pushable trolley, in particular a shopping trolley, with a contacting system, wherein the contacting system comprises: a first contact pair with at least two contact elements for a first connection pole of an electrical charging voltage; a second contact pair with at least two contact elements for a second connection pole of the electrical charging voltage; wherein the first and the second contact pair are configured such that: by pushing the pushable trolley into a second, identically constructed trolley with a second, identically constructed contacting system, at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair establishes an electrically effective contact with a respective counter-contact element of the second trolley;
wherein at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair are designed and/or arranged such that: a sliding and/or rolling contact is established between the contact elements and the counter-contact elements during at least part of the insertion process; and/or a stationary contact is established when the contact elements are in the fully inserted position.

Description

1. Field of the invention

The present invention generally relates to pushable carts, in particular "smart"/digitally equipped, manually pushable, possibly motor-assisted carts, such as those used for shopping in retail or wholesale stores, for picking items in a warehouse, or as panel carts in hardware stores. These carts may be equipped with a permanently or detachably installed tablet computer/smartphone or the like, or have a holder for a user's own smartphone or other smart device, either loaned to the user for use. In particular, the present invention relates to the field of shopping carts in supermarkets.

2. Technical background

The tablet computer or, if applicable, the customer's own device is used to facilitate shopping by automatically or manually scanning the items placed in the shopping cart by the customer. For example, this can simplify the payment process, significantly reduce customer waiting times, and increase the effectiveness and efficiency of the retailer's checkout area. To achieve this, it must be ensured that the battery of the tablet computer or, if applicable, the customer's own device has sufficient power to ensure that the purchase is not interrupted due to a lack of power.

The German patent application DE 10 2022 103 520 A1 discloses a shopping cart in which the power supply is provided via a conventional deposit lock and chain attached to the handle of the cart in the shopping cart house, where the shopping carts are pushed together, usually overnight. The battery of the cart at the front of a row is charged using a special device that is permanently installed in the house and contains a powered plug that is inserted into a socket on the deposit lock of the first cart. The battery of the next shopping cart and the batteries of all other nested shopping carts are charged via a contact system that is integrated into the deposit lock and also electrically connects the carts to one another via the chain. The disadvantage of this system is that the contact system becomes quite complex because the mechanical coupling also includes the electrical coupling. There is no guarantee that the system will function reliably for years, because customers often pull or tug on the handle of the shopping cart even though the cart is still mechanically coupled via the deposit lock. This puts stress on not only the mechanical components but also on the relatively sensitive electrical contacts. Furthermore, the chain must be insulated, as customers can directly touch this part of the shopping cart and must be protected from electric shocks. Moreover, not every shopping cart has such a chain. Many retail chains deliberately opt for shopping carts without a deposit lock or chain to save customers from having to bring a shopping cart token or coin. Many customers also have key fobs that can be inserted into a deposit lock to open it and then immediately removed again. When returning the shopping cart, the customer does not have to close the deposit lock again because there is neither a chip nor a coin inside. This interrupts the flow of electricity. A solution that uses electronic deposit lock opening also presents a further hurdle for customers when shopping, which many retailers want to avoid.

The European Patent EP 3 252 913 B1 describes a contact system in which the contacts are arranged on the outside right and left of the handlebar of the shopping trolley and are functionally separate from the mechanical coupling of the trolleys to one another. The disadvantage of this system is that a relatively high technical and structural outlay must be present in the shopping trolley hall, because there must be two railings with rails and contact rails inside them, which accommodate the contacts on the outside right and left. These devices are also expensive and space-consuming. The customer is therefore required to drive purposefully into the contact rails. This can result in customers pinching their fingers if they are not careful when pushing them in. Since the task of taking away empty shopping trolleys is often done by children, who are naturally more careless than adults anyway, this risk is increased even further.

The European patent application EP 3 644 474 A1 discloses a system that charges the shopping cart batteries without mechanical contact via induction surfaces mounted on the side of the cart. However, the counter surfaces must be installed separately for each shopping cart in the cart house, which requires a high level of technical effort and incurs high costs. The carts must also be positioned precisely; otherwise, the induction surfaces will be too far apart or unevenly spaced from each other, making battery charging inefficient, expensive, and unsustainable. Therefore, Carts may have rails installed in the floor, along which the carts must be precisely guided. These rails represent an additional technical and structural effort, they are potential tripping hazards, and they can be blocked by garbage. However, the willingness to clean up other people's garbage is generally quite low.

The object of the present invention is therefore to provide a trolley that can be pushed by hand or with motor assistance, in particular a shopping trolley, which has a contact system that is independent of the existence of a deposit lock, which requires little technical infrastructure in the shopping trolley house or at the respective stacking point of the trolleys and in which there are neither tripping hazards nor a risk of injury to the fingers of the customer or the user when returning the shopping trolley.

3. Summary of the invention

The subject matter according to the invention with the features of claim 1 solves this problem, but can also be used for the other vehicles mentioned at the beginning.

The subclaims contain advantageous developments and improvements of the respective subject matter of the invention.

Hand-pushed trolleys according to the invention are, in particular, shopping trolleys, so-called cash & carry trolleys or trolleys, transport trolleys, and panel trolleys that can be pushed into one another, also referred to as nestable, with or without motorized assistance from one or more drive wheels. Particularly in the form of shopping trolleys, they can be equipped with a shopping basket and with or without an additional shelf for goods underneath the shopping basket. The present invention is described below with reference to its use for shopping trolleys, along with its features and advantages, which are at least largely transferable to the other trolley types mentioned.

A first aspect of the present invention relates to a pushable cart, in particular a shopping cart, which is equipped with a contacting system. The contacting system comprises a first contact pair with at least two contact elements for a first connection pole of an electrical charging voltage and a second contact pair with at least two contact elements for a second connection pole of the electrical charging voltage. The first and second contact pairs are designed such that by pushing the pushable cart into a second, identically constructed cart with a second, identically constructed contacting system, at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair establishes an electrically effective contact with a respective counter-contact element of the second cart.

The contacting system thus comprises a plurality of contact elements assigned to the corresponding contact pairs. In particular, the contact elements of a contact pair are related to the connection pole belonging to the contact pair. The mating contact elements are part of the contacting system of the second, identically constructed trolley, so that electrically effective contact only occurs between contact elements that relate to the same connection polarity. Since the contact pairs and the corresponding contact elements are configured in such a way that electrical contact with a respective mating contact element of the second trolley is created when the pushable trolley is pushed into a second, identically constructed pushable trolley, this contacting system is independent of the existence of a deposit lock. Nevertheless, a conventional deposit lock with a chain can be used.

Furthermore, the contacting system is based solely on establishing contact between the contact pairs and corresponding mating contact pairs, so that little technical infrastructure is required in the shopping cart building or at the respective stacking point of the carts. In particular, no guide rails are required in the floor, as the carts are simply pushed into one another as usual. Thus, the present invention eliminates tripping hazards in the shopping cart building. Furthermore, the risk of injury to the fingers of the customer or user when returning the shopping cart is minimized, as no railings with potentially injury-prone contact rails are required. This is due to the fact that the electrically active contacts can be placed at locations relatively far forward on the chassis or on the basket of the shopping cart, or at other locations outside the operating range of the cart, from which the customer is reliably far away when pushing the carts together and with which the customer does not come into contact even in the event of clumsy behavior (in the case of children). These are significant advantages, as tripping hazards and possible injuries can often lead to liability problems. Furthermore, the contact between the contact elements and the counter-contact elements is automatically established when the carriages are pushed together, so that no additional hands are required. ments on the part of the customer are necessary. Furthermore, no inductively effective contact surfaces are necessary in the building, because the contact system according to the invention can be based on touching contacts, and the cars can each charge themselves on the contact elements of the car in front of it.

In addition, at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair can be designed and/or arranged such that a sliding and/or rolling contact is established between the contact elements and the counter-contact elements at least during part of the insertion process and/or a stationary contact is established when the contact elements are in the fully inserted position.

If contact is made between the contact elements and the counter contact elements during part of the pushing-in process, contact between the corresponding contact systems is guaranteed, even if the trolleys are not in the fully pushed-in position. This means that the electrical charging voltage is also transmitted to trolleys that have not been fully pushed in by the customer or user upon return. A trolley that is not fully pushed in can be due, among other things, to an insufficiently forceful pushing-in process and/or a customer in a hurry. The use of sliding and/or rolling contacts minimizes the force required during the pushing-in process, maximizes the probability that the trolley will be returned in the fully pushed-in position, and optimizes the transmission of the charging voltage to all trolleys nested in a row. The stationary contact established in the fully pushed-in position allows the charging voltage to be transmitted to the pushable trolley for the entire period in which the trolley is in the fully pushed-in position, i.e., for a period in which the trolley is not actively used by the customer. This leads to an efficient allocation of the carriage's usage time. The part of the insertion process in which contact is established between the contact elements and the counter-contact elements is preferably located in the second half of the insertion process and immediately precedes the establishment of the stationary contact.

However, it is emphasized that a sliding, rolling and/or stationary contact as described above is not mandatory, and other embodiments described herein may do without this aspect.

In particular, the contacting system can be configured to supply power to the pushable trolley, preferably to supply power to a battery of the pushable trolley and/or an electrical device connected to the battery.

The first and second connection terminals of the electrical charging voltage can be used to charge a battery belonging to the pushable cart. This battery can be mounted on the cart and used to power an electrical, power-consuming device connected to the battery. This device can be permanently connected to the shopping cart or a customer-owned or loaned device that can be reversibly coupled to the shopping cart, e.g., a tablet computer, smartphone, and/or barcode scanner. Alternatively or additionally, the battery can be used to operate a drive motor for the cart.

In particular, it is primarily irrelevant which power-consuming device the contact system according to the invention is used for, as it can be used for any power-consuming device present on the vehicle. From today's perspective, all types of "smart devices" such as tablet computers, mobile phones, etc. are particularly suitable, but also vehicles that are not equipped with these smart devices, for example, where only the battery for an electric drive motor for one or more wheels is present on the vehicle and is charged according to the invention.

The contact system is part of the shopping cart's electrical system. Additional components include connecting cables, possibly with plug-in and/or soldered contacts, that lead from the contact elements to a battery and/or a tablet computer and/or to a charging or storage cradle for a customer's smartphone, possibly located on the handle or basket of the shopping cart, if smartphone charging is offered as a free service or if the customer uses a shopping app intended to support the purchase process in some way.

Furthermore, at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair can be configured such that they each serve as a counter-contact element for a third, identically constructed carriage when the third, identically constructed carriage is pushed into the carriage. Therefore, if two or more sliding carriages are nested in a row, the contact elements of the respective contact pairs configured as counter-contact elements effectively allow a continuous Contacting of all cars nested in series. This allows the electrical charging voltage to be transferred from one car to the next.

Additionally or alternatively, it may be a trolley that can be pushed manually or with motor assistance, in particular a shopping trolley, with a battery for operating a power-consuming device that is permanently connected to the shopping trolley, or a customer-owned device or one that is loaned to the customer and can be reversibly coupled to the shopping trolley, or for operating a drive motor for the trolley, wherein the shopping trolley has a contact system that is designed to supply the battery with power by contacting it with an identical contact system of another trolley that is already supplied with power,
wherein the contacting system of the carriage has at least one contact pair for a first connection pole of an electrical charging voltage and at least one contact pair for a second connection pole of the charging voltage, wherein at least two contact elements of a contact pair are each conductively connected to one another and wherein at least one of the at least two contact elements is designed to establish a mechanically and electrically effective contact with a mating contact element of another carriage having an identical contacting system when the carriage is pushed into the other carriage from behind in a nesting manner, wherein the contact elements and the mating contact elements are designed and arranged in such a way that they already create a sliding or rolling contact during the pushing-in process, which contact remains as a stationary touch contact when the carriage is fully pushed in.

The charging voltage is preferably a direct voltage in the low voltage range below 24 volts.

Preferably, exactly two contact elements are provided per contact pair and terminal pole. Despite the term "contact pair," a contact pair can optionally have more than two contact elements.

According to the invention, the contact elements of a contact pair are provided at such locations on the chassis, on storage surfaces or on a possibly existing shopping basket of the trolley, which, when a trolley is pushed into another trolley in front of it, approach each other in a sufficiently predictable manner so closely that the contact elements and the associated counter-contact elements reliably form the desired electrical contact and/or a mechanically effective contact with each other.

In the following, some preferred mounting locations for the contact elements are explained, which are particularly suitable for the formation of sliding contacts in which an exemplary contact directed from the inside outwards or a contact directed from the bottom up is created.

In certain embodiments of the sliding carriage, at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair can be directed toward the inside of the sliding carriage. Furthermore, at least one of the contact elements of the first contact pair and/or at least one of the contact elements of the second contact pair can be directed toward the outside of the sliding carriage, wherein the contact element directed toward the outside of the sliding carriage is conductively connected to the contact element of the respective contact pair directed toward the inside of the sliding carriage.

The outward-facing contact elements serve to make contact with the second, identically constructed carriage, whereby the outward-facing contact elements come into contact with the inward-facing contact elements of the second carriage. The inward-facing contact elements of the carriage can further form an electrically effective contact with the outward-facing contact elements of a third, identically constructed carriage, which is inserted into the carriage in a nesting manner. The conductive connection between the inward-facing and outward-facing contact elements serves to transmit the electrical charging voltage from the second, identically constructed carriage to the third, identically constructed carriage.

The contact elements of the first contact pair can be mounted on a left side of the carriage, preferably on a chassis of the carriage, and/or the contact elements of the second contact pair can be mounted on a right side of the carriage, preferably on the chassis. Alternatively or additionally, the contact elements of the first contact pair can be mounted on a left front edge of the carriage, preferably on the chassis of the carriage, and/or the contact elements of the second contact pair can be mounted on a right front edge of the carriage, preferably on the chassis.

The contacting system can be arranged on a left and a right outer side and/or on a left or right front edge of the chassis or the shopping cart as a contact pair, in each case a first, outwardly directed contact element and an inwardly directed second contact contact element, with the contact elements on one side being conductively connected to each other. Under normal circumstances, the outer sides of the chassis or shopping cart, located to the right and left in the direction of travel, and their respective inner sides always come so close to each other during nesting that contact with the contact elements described below is reliably achieved. <see previous figures>

Furthermore, the contact elements directed towards the outside of the pushable trolley can each be formed around a front edge of the trolley so that they form part of a left or right side and part of a front side of the chassis and/or a basket of the trolley.

If the outward-facing contact elements are each designed to go around the front edge of the lower frame member or basket, so that they form part of the outside and part of the front of the chassis member or basket, the advantage is that the contact is particularly reliable, especially when the carriages are not pushed into one another completely parallel during nesting.

In certain embodiments of the pushable carriage, the first and second contact pairs can be arranged such that at least one of the contact elements of the first contact pair and/or at least one of the contact elements of the second contact pair is directed upwards, and at least one of the contact elements of the first contact pair and/or at least one of the contact elements of the second contact pair is directed downwards. The contact elements of a contact pair are each conductively connected to one another.

Furthermore, the pushable trolley can have a, preferably pivotable, storage level, wherein the first and/or second contact pair are arranged on the storage level. Alternatively or additionally, the trolley can have a shopping basket, wherein the first and/or second contact pair are arranged on the shopping basket.

The contacting system can - if, for example, a pivoting lower storage level is present - have two contact pairs mounted at a sufficient lateral distance from each other: a first, upward-facing contact element and a second, downward-facing contact element. The contact elements of a pair are each conductively connected to each other. This contacting system can be used advantageously not only for typical "plate trolleys," but also for shopping carts, where the pivoting lower storage level is located below the shopping cart.

As an alternative to or in combination with one of the two attachments described above, if a shopping cart is present, the contacting system can comprise two contact pairs mounted there, e.g., at the bottom of the basket, with sufficient lateral spacing from one another. Each contact pair has a first, upward-facing contact element and a second, downward-facing contact element, with the contact elements of a pair each being conductively connected to one another. Here, too, the underside of the basket bottom of the rolling-in cart comes sufficiently close to the top side of the basket bottom of the cart in front during nesting, both in the vertical direction and in its right-left orientation.

Furthermore, at least one of the contact elements of the pushable carriage can have a contact surface, preferably a contact strip with a predetermined length and width.

For example, in the case of contact directed from the inside outwards, the outward-facing contact elements can advantageously each be designed as a flat contact strip with a predetermined length and width, whereby the length and width should be adapted to the specific installation location. The contact strips are preferably attached to the lower frame of the shopping trolley, to which the holders for the trolley's wheels are also attached. These are often bars with a rectangular cross-section, an external lateral height of approximately 30 mm and a hollow interior. In this case, the outward-facing contact element would preferably be a strip less than 30 mm wide and approximately 15 cm long if attached purely laterally, and preferably 20 cm long if the contact strip is continuous along the side of the bar and at the front of the bar. These dimensions are to be understood as examples. For example, contact surfaces with a width of at least 2 mm, at least 5 mm and/or at most 20 mm, at most 30 mm can generally be provided. A length can generally be at least 2 cm, at least 5 cm, at least 15 cm or at least 20 cm.

When the outward-facing contact elements are attached to the shopping cart, they can have similar length and width dimensions. They are then advantageously mounted near the bottom of the shopping cart to minimize interference with the mating contact elements inside the shopping cart.

In certain embodiments of the pushable carriage, at least one section of at least one of the contact elements of the first contact pair can be flexible and/or at least one section of at least one of the contact elements of the second contact pair can be flexible, such that the at least one flexible section exerts permanent pressure on the respective counter-contact element in the at least partially inserted state. The at least one flexible section is preferably directed inward and/or downward.

This creates the advantage of reliable and robust contact, which is present even if the trolley is not parked perfectly symmetrically or not completely pushed forward in the row of trolleys. The flexibility can be achieved by various means depending on the shape used, material thickness and size of the inward-facing contact elements. If elongated strips are used as the shape, which have a certain rigidity and robustness due to the material, then the flexibility can be advantageously achieved by having one end of the strip firmly attached to the pole or basket, and the remaining part of the contact strip extending freely cantilevered further inwards at the same height. The inward-projecting end section is preferably bent outwards in a round shape to avoid causing scratching contact with the outward-facing mating contact element. Sliding contact when pushed together is preferred. If the inner contact element is less rigid but also has an elongated structure, it can also be attached to a second point on the pole. Semi-oval or oval shapes are suitable, which are pressed into a more elongated shape when pushed together. The advantage is that such a closed shape is more resistant to vandalism because it cannot be bent as easily and therefore does not lose its flexibility.

Alternatively, or in combination with the material's inherent flexibility, flexibility can also be achieved through suitable spring elements mounted between the contact element and the frame beam or basket, preferably attached on both sides. Springs, clips, and buffers made of plastic or rubber are advantageously used in this case. Relatively strong, non-corrosive pairs of flat magnets can also be mounted between the beam or basket and the contact element in such a way that they repel each other and press the contact element against the mating contact element.

With bottom-up contact on the basket base or on the pivoting lower product storage area, the upward-facing contact elements are located in an area on which goods can be placed. Therefore, the upward-facing contact elements are advantageously also designed as contact strips with a predetermined length and width, approximately as described above, and the edges of the contact elements do not protrude upwards, so that there is no risk of injury to the customer. The same applies to the downward-facing contact elements on the underside of the basket base or on the underside of the lower, pivoting storage area as previously explained for the inward-facing contact elements. They are either flexible due to their material properties or, due to their design, movable with a spring or magnet with a certain restoring force, so that a sliding contact and a permanent restoring contact in the fully retracted position are created.

The contact elements can be made of an electrically conductive, homogeneous material that is as corrosion-resistant as possible and has a low tendency to break due to the repeated bending. Possible materials include stainless steel, preferably chrome-plated, galvanized or chrome-plated copper, or aluminum. However, composite materials can also be used, preferably a plastic carrier that provides flexibility and a conductive layer of a suitable material applied to it. The connection can be mechanical, for example, with rivets or screws, or it can be adhesively bonded.

The contact elements are attached to the chassis beam using a permanent, low-vulnerability connection such as gluing, a screw connection that prevents loosening, or welding, if appropriate. All of these connections should ensure a secure position of the contact elements without any risk of the contact element swinging loosely. The connection must ensure that no charging current flows from the contact element into the metal of the frame beam.

Preferably, the contact element has an extension made of the same material as the shopping cart, allowing it to be inserted into the shopping cart through an opening in the frame beam or into a cable duct on the shopping cart. This has the advantage that an electrically effective connection of the extension to a cable is provided by a plug connection or as a solder joint inside the beam or cable duct, thus protecting it from external access and weather influences.

The pushable carriage can comprise a system for maintaining contact, wherein the system for maintaining contact comprises at least a first and at least a second system element such that a positive connection is established between the at least one first system element of the carriage and a second counter-system element of the second, identically constructed carriage when the second carriage is pushed into the first carriage and the electrically effective contact is established in the process.

Preferably, a contact-maintaining system is provided on a chassis or a basket. Such a contact-maintaining system largely prevents an electrical contact, once established between two trolleys in a row during nesting, from being broken again by the removal of the rearmost trolley in the row.

Furthermore, the pushable carriage may have a chassis with at least one beam, wherein a male system element is provided on an inner side of the beam and a female system element is provided on an outer side of the beam.

Preferably, the form fit is achieved by providing a male system element on the inside of a chassis pillar and a female system element of matching shape on the outside of the pillar. This has the advantage that the outer contour of the trolley is not altered by protruding individual parts that could cause customers to bump into it.

Furthermore, the system for maintaining contact can be provided by shaping contact elements that fit together and are in contact with each other.

• Dann weisen die Kontaktelemente eine Form auf, die bewirkt, dass nach Einschieben des Wagens in seinen Vordermann der frisch eingeschobene Wagen im Berührungskontakt bleibt. Ein ungewolltes Zurückrollen und damit ein Lösen des elektrischen Kontaktes wird demgemäß bevorzugt durch einen Formschluss der beiden, sich berührenden Kontaktelemente verhindert. Der Formschluss kann beispielsweise durch eine entsprechende, sanft verlaufende Eindellung des einen Kontaktelements geschaffen sein, in die bei Kontakt eine entsprechende Ausbuchtung des anderen Kontaktelements hineingreift. Der Formschluss sollte andererseits beim Herausholen des Einkaufswagens durch den nächsten Kunden leicht überwindbar sein. Beides ist durch die relativ sanft verlaufende Gestaltung der Eindellung und Ausbuchtung sowie durch eine nicht zu geringe Steifigkeit der Kontaktelemente erreichbar.

The contact-holding system can be mounted on the shopping cart independently of the contact-holding system. It can also be integrated into the contact-holding system, as follows:

• The contact elements then have a shape that ensures that after the trolley has been pushed into the person in front of it, the newly pushed-in trolley remains in contact. Accidental rolling back and thus a loss of electrical contact is preferably prevented by a positive locking of the two contact elements. The positive locking can be created, for example, by a corresponding, gentle indentation in one contact element, into which a corresponding bulge in the other contact element engages upon contact. On the other hand, the positive locking should be easy to overcome when the next customer retrieves the shopping trolley. Both of these can be achieved by the relatively gentle design of the indentation and bulge and by the contact elements being sufficiently rigid.

Alternatively, the system for maintaining mechanical contact can be achieved independently of the electrical contact by a magnetically induced force connection between one or two pairs of magnets, one attached to the front of the chassis's front beam and the other to the rear of a cross beam located slightly behind it, which is already present on the trolley. This creates a defined position in which one trolley is pushed into another to the maximum extent. The magnetic force should be adjusted so that the trolley is secured against rolling away, but can also be pulled towards the customer without excessive resistance.

In certain embodiments, the pushable trolley can include a power connection that is electrically connected to the contacting system. Preferably, the trolley has a power connection, e.g., a DC connection, in the form of a plug that is electrically connected to the contacting system, as described above. It can be used after business hours for the last trolley in the row of trolleys if a faulty contact occurs somewhere within the row, by connecting a supply cable belonging to the trolley housing with a live socket to the plug of the last trolley. In this way, the rear trolleys are still supplied with power until the faulty contact occurs.

According to a further aspect, the present invention comprises a device for insertion into a rearmost carriage of a nested row of pushable carriages, wherein the device has a contacting system. The contacting system of the device contains contact elements such that, by inserting the device into a pushable carriage according to the invention, electrical contact can be established with respective counter-contact elements of the pushable carriage according to the invention.

The device according to the invention can further comprise a power connector that is conductively connected to the contacting system. The device can be inserted into the rearmost trolley of a nested row of pushable trolleys after the store closes or when generally needed, with the power connector connected to a corresponding power or voltage source. This allows the cars nested in series to be supplied with power from both sides, i.e., from the front and the rear.

This can not only speed up the charging process itself, but also minimizes the risk of not charging some of the cars nested in a row if no electrically conductive contact has been established between two cars in the row.

The present invention further comprises a docking station configured to supply power to a frontmost, push-along cart nested in a row. The docking station preferably has a power connection that can be connected to a power grid. In certain embodiments, the docking station is a permanently installed element, for example, in and/or on a wall, on the floor, or the docking station is part of a cart housing. Alternatively, the docking station can also be portable, so that it can be used in locations where push-along carts have been nested in a row. The docking station comprises a contacting system, wherein the contacting system contains contact elements such that by pushing the push-along cart according to the invention toward and/or into the docking station, electrical contact can be established with respective counter-contact elements of the push-along cart according to the invention. The established electrical contact between the docking station and the push-along cart according to the invention allows the cart to be supplied with power, wherein a battery connected to the cart is preferably supplied with power.

According to a further aspect, the present invention comprises a contacting system for mounting on a push-pull cart, e.g., a cart described herein. This contacting system comprises a first contact pair with at least two contact elements for a first connection pole of an electrical charging voltage and a second contact pair with at least two contact elements for a second connection pole of the electrical charging voltage. The first and second contact pairs are configured such that the first and second contact pairs each have at least two contact elements, and by pushing the push-pull cart into a second, identically constructed cart with a second, identically constructed contacting system, at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair establishes an electrically effective contact with a respective counter-contact element of the second cart.

Furthermore, the present invention comprises a retrofit kit for a pushable cart (as described herein), in particular a shopping cart, with the contacting system according to the invention.

The retrofit kit according to the invention enables the cost-effective integration of push carts without a contact system into the corresponding charging system of push carts with the contact system according to the invention. Push carts without a contact system can, for example, be older existing carts in a store. In particular, the retrofit kit allows for quick and efficient repair of push carts.

The retrofit kit and/or the (separate) contacting system may be configured as described herein with respect to a contacting system already mounted on the vehicle.

According to a further aspect of the present invention, the shopping cart according to the invention can be used in conjunction with a charging logic system. This charging logic system can be used to coordinate the charging current of the nested shopping carts connected in series and is preferably used in a supermarket. The charging logic system can be software-based and/or hardware-based.

In certain embodiments, the charging logic comprises a control unit located on the trolley. Using this control unit, the trolley can, for example, adjust the charging current to be consumed. The control unit can have at least one processor and/or microcontroller and/or at least one storage medium, wherein at least one processor and/or microcontroller can be operatively connected to at least one storage medium. The storage medium can contain a predetermined charging configuration and/or an algorithm configured to coordinate and/or regulate the charging current and executed accordingly by the processor (or microcontroller). The predetermined charging configuration can be fixed such that the trolley can control or regulate the charging current independently, i.e., the trolley does not require any external, additional data and/or commands for control or regulation. In further embodiments, the charging configuration can depend at least partially on the registration of a third, identically constructed trolley nested in the trolley. If the trolley registers the third trolley, the third trolley can adapt the charging configuration such that, thanks to the contact system, the third trolley is also still sufficiently supplied with power. This sufficient power supply of the third The third car may result in a reduction in the car's power supply. Therefore, in a preferred embodiment, the car draws the maximum available charging current if no third car is registered.

In general, the pushable cart can be connected to a backend permanently, or at least during the charging process, via at least one docking station using a wireless transmission method. To establish a connection to the backend, the pushable cart and/or the docking station can be equipped with a corresponding interface. The wireless transmission method can be, for example, a WLAN connection. The backend can be implemented on a computer belonging to the supermarket and/or in a cloud solution. Each of the shopping carts can send data to the backend using the wireless transmission method. This data can be shopping cart-specific and can include, for example, at least the current battery level of the respective shopping cart. The data can also include a temperature. The backend can collect and summarize the data received from the shopping carts and/or create a charging prioritization of the nested shopping carts. The charging prioritization shows, for example, which of the shopping carts need to be charged most urgently and/or which do not need to be charged. The backend can send the charging prioritization back to the shopping carts, which can then determine their corresponding charging prioritization, e.g., whether the shopping cart should be charged or not and/or the charging voltage or charging current available to the shopping cart. The shopping carts themselves can control the charging current intake according to the charging prioritization. This control can include the intake of charging current from the series connection as well as the passing of the charging current to the nested following cart.

As already explained, during the charging process, the shopping carts can be in contact with at least one docking station, which supplies power to the nested shopping carts. This leads to the shopping carts at the back of the row being used more frequently than the shopping carts at the front. Consequently, the shopping carts at the back generally have a lower battery level and should therefore be prioritized for charging to enable the battery to be charged as quickly as possible. If the battery level of the rear carts is below a threshold, the backend can configure the charging prioritization such that all shopping carts with a battery level above the threshold receive no charging current, and the rear carts (e.g., two, three, or four) below the threshold receive the maximum possible charging current. The threshold can be set, for example, to a maximum of 20% of the maximum battery level, preferably a maximum of 40% of the maximum battery level.

Furthermore, at least one of the shopping carts can be equipped with a temperature sensor such that it sends temperature data to the backend. The temperature data can be transmitted to the backend together with the battery level data. Based on the received temperature data, the backend can determine a temperature, which can be the minimum, the maximum, the mean, the median, or a function of the received temperature data. If this temperature is below a threshold, the backend can inform the shopping carts that they should not draw any charging current. The threshold can be at least 10°C, preferably at least 5°C, since at such temperatures the battery could be damaged during the charging process. Alternatively or additionally, there can also be another, stationary thermometer that is not attached to one of the shopping carts.

In addition, the backend can also send data to the shopping carts that includes a time. The time can include the time at the time the time is sent, the date, and/or the day of the week, whereby the time can refer to the time at the location of the supermarket. Furthermore, the time can include the closing time of the supermarket. The time signal can be sent continuously by the backend and/or at intervals. For example, the time signal can be sent at least every 10 minutes, preferably at least every 20 minutes. Furthermore, the time signal can be sent periodically. If the time is within a time window before the closing time of the supermarket, this can lead to a change in the configuration of the charge level LEDs and/or contact status LEDs described herein. The time window can, for example, include a period of at least 30 minutes, preferably at least 15 minutes. In a first configuration, which can be active during shopping operations, the charge level LEDs do not light up or light up green to signal to the customer that the corresponding shopping cart is ready for use. In a second configuration, which can be activated by the time signal, the charge level LEDs can be configured to indicate whether the battery of the corresponding shopping cart is charging. For example, the charge level LEDs can light up red if the shopping cart is connected to the power grid. This display technology allows A supermarket employee can immediately determine whether all carts nested in a row are receiving power. In particular, the employee can immediately identify an interruption and/or defect. In other examples, the configurations mentioned can also be used independently of one another, for example, permanently.

Additionally or alternatively, the shopping carts can also exchange data directly with each other without involving a backend. Each shopping cart can receive data from other shopping carts, preferably only receiving data from shopping carts in the shopping cart's vicinity. This vicinity can have a maximum extent of 20 m, preferably a maximum of 10 m. Limiting the vicinity to a maximum extent of 20 m leads to a reduction in communication overhead. Based on the received data, each shopping cart determines, for example, whether it is entitled to charging current and/or how much charging current it is entitled to. For this purpose, control units of the shopping carts can be equipped with a corresponding algorithm.

In a further embodiment, the backend is further connected to a solar system, which supplies at least part of the charging current. The solar system can consist of one or more solar panels and is preferably installed on the supermarket and/or on buildings close to the supermarket. If the solar system supplies enough power to charge all shopping carts, all shopping carts are charged with the maximum available power. This can occur, for example, during a period in which the sun is shining and thus sufficient solar power is produced. If the solar system supplies less power than is necessary to charge all shopping carts, each shopping cart only draws enough power to maintain operation. In general, the shopping carts' power consumption can be controlled depending on a current sunshine parameter and/or a current electricity price.

4. Brief description of the drawings

• 1 zeigt einen smarten Einkaufswagen auf Rollen in einer schematischen Seitenansicht, mit einem unteren und einem hinteren Rahmenholm, mit einem Warenkorb auf einem Stützgestell, und mit einem Tabletcomputer, sowie mit einem erfindungsgemäßen Kontaktierungssystem mit einem Pärchen von Kontaktelementen pro Seite (rechts-links) einschließlich Kabelführung zum Tabletcomputer.
• 2 zeigt in vereinfachter Darstellung das Fahrgestell mit den seitlichen Holmen und dem vorderen Holm, sowie mit einem Kontaktierungssystem nach 1, schematisch von oben, wobei zwecks besserer Klarheit nur die Fahrgestelle mit dem Kontaktierungssystem gemäß Erfindung dargestellt sind.
• 3 zeigt in vereinfachter Darstellung zwei ineinander genestete Einkaufswagen gemäß 2, aber unter Weglassung der Kontaktepärchen 32, 42, wobei zwecks besserer Klarheit nur die Fahrgestelle mit den Kontaktierungssystemen gemäß Erfindung dargestellt sind.
• 4 zeigt in vereinfachter Darstellung den ersten Einkaufswagen, der in ein Kontaktierungssystem eines Basisadapters eingeschoben ist, wobei der Basisadapter an eine Gleichstromversorgung angeschlossen ist und einen elektrischen Kontakt zu den in der Zeichnung oben dargestellten Kontaktelementen des Einkaufswagens herstellt.
• 5 zeigt einen Einkaufswagen gemäß 1 mit einer am Boden befindlichen Haltevorrichtung in der Kopplung mit dem Basisadapter aus 4, in einer schematischen Seitenansicht.
• 6 zeigt eine genestete Reihe von Einkaufswagen, bei der der dritte Wagen von oben nicht vollständig in den zweiten eingeschoben wurde und es nicht zu dem gewünschten elektrischen Kontakt kommt, siehe Detail rechts.
• 7 zeigt einen schief eingeschobenen Wagen der aufgrund seiner redundanten Kontaktelemente vorn rechts und links dennoch eine ausreichende Ladekontaktierung bekommt.
• 8a bis 8e zeigen mehrere Formen zur Ausgestaltung der innen liegenden Kontaktelemente 42 oder 44 aus 2 als Varianten in schematischer Ansicht.
• 9 zeigt ein außen liegendes, um die Vorderkante herumgeführtes Kontaktelement 34 aus 2 für die rechte Seite des Einkaufswagens schematisch in mehreren Perspektiven unter Weglassung der Kontaktierung zu einer Buchse des Kabels im Inneren des Holms, wobei 9a eine seitliche Ansicht von außen, 9b eine seitliche Ansicht von innen, 9c eine perspektivische Ansicht von hinten außen oben und 9d eine Draufsicht von oben darstellt.
• 10 zeigt ein innenliegendes Kontaktelement 42 oder 44 aus 2 für die rechte Seite des Einkaufswagens schematisch in mehreren Perspektiven unter Weglassung der Kontaktierung zu einer Buchse des Kabels im Inneren des Holms, wobei 10a eine seitliche Ansicht auf die am Holm anliegende Rückseite, 10b eine Ansicht von hinten, 10c eine perspektivische Ansicht von hinten außen oben und 10d eine Draufsicht von oben darstellt.
• 11a zeigt eine beispielhafte Kontaktierung eines innen liegenden Kontaktelement mit einem Anschlusskabelstück, das mit einem Kabel mittels einer Steckverbindung verbunden werden soll, das im Inneren des Holms verläuft; 11b zeigt entsprechend eine beispielhafte Kontaktierung eines außen liegenden Kontaktelements.
• 12 zeigt eine beispielhafte Kontaktierung zwischen einem innen liegenden Kontaktelement und einem Kabel, das im Inneren des Holms verläuft, mittels einer Steckverbindung, sowie die Kontaktierung für ein außen liegendes Kontaktelement, beide auf der rechten Seite im Montagezustand für die Kontaktherstellung und auf der linken Seite im fertig montierten Zustand angeschraubt an den Holm 12 nach Herstellung der elektrischen Kontakte.
• 13 zeigt zwei ineinander geschobene, erfindungsgemäße Einkaufswagen in einer Draufsicht auf das Fahrgestell, bei denen gemäß einer Variante der vorliegenden Erfindung der waagerechte Holm jeweils auf seiner Innenseite eine erste, kleine Auswölbung besitzt, und der Holm auf seiner Außenseite eine zweite kleine Auswölbung besitzt.
• 14a zeigt ein erfindungsgemäß vorgesehenes „Dummy“- Einkaufswagengestell in einer schematischen Ansicht von oben, das einen am Einkaufswagenhaus installierten, für den letzten Wagen einer genesteten Reihe gedachten, zusätzlichen Stromanschluss aufweist, in einer schematischen Teilansicht von oben im genesteten Zustand, 14 b zeigt das „Dummy“-Einkaufswagengestell schematisch perspektivisch von vorne oben ohne Kabel, und 14c zeigt das „Dummy“- Einkaufswagengestell schematisch von oben mit Anschlusskabel.
• 15 zeigt einen erfindungsgemäß ausgestatteten Einkaufswagen mit einem Kabelkanal, der vom unteren Holm bis zum Tablet führt.
• 16 zeigt einen erfindungsgemäß ausgestatteten Einkaufswagen gänzlich ohne hohle Holme, mit Kabelkanal, der von den vordersten Kontaktelementen bis zum Tablet führt.
• 17 zeigt in einer schematischen Seitenansicht einen erfindungsgemäß ausgestatteten Einkaufswagen, bei dem die Kontaktelemente seitlich rechts und links unten am Warenkorb befestigt sind.
• 18 zeigt in einer schematischen Draufsicht den Einkaufswagen aus 17.
• 19 zeigt in einer schematischen Seitenansicht einen erfindungsgemäß ausgestatteten Einkaufswagen, bei dem die Kontaktelemente seitlich rechts und links oben am Warenkorb befestigt sind.
• 20 zeigt in einer schematischen Seitenansicht einen erfindungsgemäß ausgestatteten Einkaufswagen ohne untere Ablageebene, mit einem Fahrgestell, das vier schräg vom Warenkorb nach unten verlaufende Holme besitzt, die zu den Rollen verbinden, und bei dem die Kontaktelemente unten am Warenkorb befestigt sind.
• 21 zeigt in einer schematischen Seitenansicht einen erfindungsgemäß ausgestatteten Einkaufswagen ohne untere Ablageebene, mit einem Fahrgestell, das vier schräg vom Warenkorb nach unten verlaufende Holme besitzt, die zu den Rollen verbinden, und bei dem die Kontaktelemente an den beiden vorderen Schrägholmen oberhalb der Rollen befestigt sind.
• 22 zeigt den Einkaufswagen aus 21 in einer schematischen, nur mit den Umrissen des Korbs freigelegten Ansicht von oben.
• 23a zeigt zwei Einkaufswagen aus 21, vollständig genestet, in einer schematischen, nur mit den Umrissen des Korbs freigelegten Ansicht von oben.
• 23b zeigt einen Ausschnitt auf den in Fahrtrichtung rechten vorderen Schrägholm mit den Kontaktpärchen in einer schematischen seitlichen Ansicht von schräg außen vorn und oben.
• 23c zeigt die Befestigungsstelle der Kontaktpärchen von vorn.
• 23d zeigt eine schematische, seitliche Ansicht von außen auf den Schrägholm mit den Kontaktpärchen.
• 23e zeigt eine schematische Ansicht von oben auf den Schrägholm mit den Kontaktpärchen.
• 23f zeigt den Ausschnitt aus 23a von innen.
• 24 zeigt in einer schematischen Seitenansicht einen Einkaufswagen mit unterer, schwenkbarer Ablageebene, bei dem zwei mit ausreichendem seitlichen Abstand zueinander und nebeneinander angebrachte Kontaktpärchen - wobei wegen der Seitenansicht nur ein Kontaktpärchen abgebildet ist - unter dem Warenkorb an einer unteren Ablageebene angeordnet sind, wobei jedes Kontaktpärchen ein erstes, nach oben gerichtetes Kontaktelement und ein zweites nach unten gerichtetes Kontaktelement aufweist.
• 25 zeigt zwei genestete Einkaufswagen gemäß 24 in einer Seitenansicht, wobei der Kontakt zwischen nach oben gerichtetem Kontaktelement des hinteren (links dargestellten) Einkaufswagens und dem nach unten gerichteten Kontaktelement des vorderen Einkaufswagen dargestellt ist.
• 26 zeigt in einer schematischen Seitenansicht einen Einkaufswagen mit einem Einkaufskorb, mit zwei, mit ausreichendem seitlichen Abstand zueinander am Korbboden angebrachte Kontaktpärchen, - wobei wegen der Seitenansicht nur ein Kontaktpärchen abgebildet ist - wobei jedes Kontaktpärchen ein erstes, nach oben gerichtetes Kontaktelement und ein zweites nach unten gerichtetes Kontaktelement aufweist.
• 27 zeigt zwei genestete Einkaufswagen gemäß 26 in einer Seitenansicht, wobei der Kontakt zwischen nach oben gerichtetem Kontaktelement des hinteren (links dargestellten) Einkaufswagens und dem nach unten gerichteten Kontaktelement des vorderen Einkaufswagen dargestellt ist.
• 28 zeigt in einer schematischen Seitenansicht einen Einkaufswagen mit einem Einkaufskorb, mit zwei, am oberen Korbrand angebrachten Kontaktelementen - wobei wegen der Seitenansicht nur ein Kontaktelement abgebildet ist - und zwei an der schwenkbaren Korbrückwand angebrachten Kontaktelementen - wobei wegen der Seitenansicht ebenfalls nur ein Kontaktelement abgebildet ist - die zusammen jeweils ein Kontaktpärchen bilden.
• 29 zeigt zwei genestete Einkaufswagen gemäß 28 in einer Seitenansicht, wobei der Kontakt zwischen nach oben gerichtetem Kontaktelement am Korbrand des hinteren (links dargestellten) Einkaufswagens und dem nach unten gerichteten Kontaktelement an der schwenkbaren Korbrückwand des vorderen Einkaufswagen dargestellt ist.
• 30 zeigt in einer schematischen Seitenansicht einen Einkaufswagen mit einem elektromotorisch angetriebenen fünften Rad und einem Akku, der von dem erfindungsgemäßen Kontaktierungssystem, das aus Gründen verbesserter Klarheit weggelassen wurde, neben dem Tablet ebenfalls mit Strom versorgt wird.
• 31 zeigt den Einkaufswagen aus 30 freigelegt ohne Korb in einer schematischen Ansicht von oben.

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

• 1 shows a smart shopping cart on wheels in a schematic side view, with a lower and a rear frame member, with a shopping cart on a support frame, and with a tablet computer, as well as with a contact system according to the invention with a pair of contact elements per side (right-left) including cable routing to the tablet computer.
• 2 shows a simplified representation of the chassis with the side beams and the front beam, as well as with a contact system according to 1 , schematically from above, showing, for the sake of clarity, only the chassis with the contacting system according to the invention.
• 3 shows a simplified representation of two shopping carts nested together according to 2 , but omitting the contact pairs 32, 42, whereby for the sake of clarity only the chassis with the contacting systems according to the invention are shown.
• 4 shows a simplified representation of the first shopping cart inserted into a contacting system of a base adapter, whereby the base adapter is connected to a DC power supply and establishes electrical contact with the contact elements of the shopping cart shown in the drawing above.
• 5 shows a shopping cart according to 1 with a holding device located on the floor in connection with the base adapter 4 , in a schematic side view.
• 6 shows a nested row of shopping carts where the third cart from the top has not been fully pushed into the second and the desired electrical contact is not made, see detail on the right.
• 7 shows a crookedly inserted trolley which, due to its redundant contact elements at the front right and left, still has sufficient charging contact.
• 8a to 8e show several shapes for the design of the internal contact elements 42 or 44 from 2 as variants in schematic view.
• 9 shows an external contact element 34 guided around the front edge of 2 for the right side of the shopping cart schematically in several perspectives, omitting the contact to a socket of the cable inside the handlebar, where 9a a side view from the outside, 9b a side view from the inside, 9c a perspective view from the back outside top and 9d represents a top view.
• 10 shows an internal contact element 42 or 44 made of 2 for the right side of the shopping cart schematically in several Perspectives omitting the contact to a socket of the cable inside the spar, whereby 10a a side view of the back adjacent to the spar, 10b a view from behind, 10c a perspective view from the back outside top and 10d represents a top view.
• 11a shows an example of contacting an internal contact element with a connecting cable piece that is to be connected to a cable by means of a plug connection that runs inside the spar; 11b shows an example of contacting an external contact element.
• 12 shows an example of contact between an internal contact element and a cable running inside the spar, by means of a plug connection, as well as the contact for an external contact element, both on the right side in the assembled state for making contact and on the left side in the fully assembled state screwed to the spar 12 after making the electrical contacts.
• 13 shows two shopping trolleys according to the invention pushed into one another in a plan view of the chassis, in which, according to a variant of the present invention, the horizontal bar has a first, small bulge on its inside, and the bar has a second small bulge on its outside.
• 14a shows a “dummy” shopping trolley frame provided according to the invention in a schematic view from above, which has an additional power connection installed on the trolley housing and intended for the last trolley in a nested row, in a schematic partial view from above in the nested state, 14 b shows the “dummy” shopping cart frame schematically in perspective from the front above without cables, and 14c shows the “dummy” shopping cart frame schematically from above with connecting cable.
• 15 shows a shopping cart equipped according to the invention with a cable duct that leads from the lower bar to the tablet.
• 16 shows a shopping cart equipped according to the invention, completely without hollow bars, with a cable duct leading from the front contact elements to the tablet.
• 17 shows a schematic side view of a shopping cart equipped according to the invention, in which the contact elements are attached to the bottom right and left sides of the shopping cart.
• 18 shows a schematic top view of the shopping cart from 17 .
• 19 shows a schematic side view of a shopping cart equipped according to the invention, in which the contact elements are attached to the top right and left sides of the shopping cart.
• 20 shows in a schematic side view a shopping cart equipped according to the invention without a lower storage level, with a chassis which has four bars running diagonally downwards from the shopping cart, which connect to the rollers, and in which the contact elements are attached to the bottom of the shopping cart.
• 21 shows in a schematic side view a shopping cart equipped according to the invention without a lower storage level, with a chassis which has four bars running diagonally downwards from the shopping cart, which connect to the rollers, and in which the contact elements are attached to the two front diagonal bars above the rollers.
• 22 shows the shopping cart 21 in a schematic view from above, with only the outline of the basket exposed.
• 23a shows two shopping carts from 21 , fully nested, in a schematic view from above with only the outline of the basket exposed.
• 23b shows a section of the right front inclined beam in the direction of travel with the contact pairs in a schematic side view from the outside at the front and above.
• 23c shows the attachment point of the contact pairs from the front.
• 23d shows a schematic, side view from the outside of the inclined beam with the contact pairs.
• 23e shows a schematic view from above of the inclined beam with the contact pairs.
• 23f shows the excerpt from 23a from the inside.
• 24 shows a schematic side view of a shopping cart with a lower, pivoting storage level, in which two contact pairs are mounted next to each other with sufficient lateral distance to each other - only one contact pair is shown because of the side view - under the shopping cart on a lower storage level are arranged, each contact pair having a first, upwardly directed contact element and a second downwardly directed contact element.
• 25 shows two nested shopping carts according to 24 in a side view, showing the contact between the upward-facing contact element of the rear shopping cart (shown on the left) and the downward-facing contact element of the front shopping cart.
• 26 shows a schematic side view of a shopping cart with a shopping basket, with two contact pairs attached to the bottom of the basket with sufficient lateral distance from each other - only one contact pair is shown because of the side view - each contact pair having a first contact element directed upwards and a second contact element directed downwards.
• 27 shows two nested shopping carts according to 26 in a side view, showing the contact between the upward-facing contact element of the rear shopping cart (shown on the left) and the downward-facing contact element of the front shopping cart.
• 28 shows a schematic side view of a shopping trolley with a shopping basket, with two contact elements attached to the upper edge of the basket - only one contact element is shown because of the side view - and two contact elements attached to the pivoting rear wall of the basket - only one contact element is shown because of the side view - which together form a contact pair.
• 29 shows two nested shopping carts according to 28 in a side view, showing the contact between the upwardly directed contact element on the basket edge of the rear shopping cart (shown on the left) and the downwardly directed contact element on the pivoting basket back wall of the front shopping cart.
• 30 shows a schematic side view of a shopping cart with an electric motor-driven fifth wheel and a battery which, in addition to the tablet, is also supplied with power by the contact system according to the invention, which has been omitted for reasons of improved clarity.
• 31 shows the shopping cart 30 exposed without basket in a schematic view from above.

5. Detailed description of preferred embodiments

The following are based on the 1-31 Some preferred embodiments for shopping carts are explained in more detail. It is emphasized that the aspects explained therein can also be applied to other types of push carts, e.g., those described above.

In the figures, the same reference symbols denote the same or functionally identical components.

1 shows a smart shopping cart 10 on wheels in a schematic side view, with a lower, horizontal frame member 12 and a rear vertical frame member 14, with a shopping cart 16 on a support frame 18, and with a tablet computer 20, as well as with a contacting system 30 according to the invention with two redundantly effective pairs 32, 34 of contact elements per side (right-left) including cable 36 with cable routing within the hollow members 12, 14 to the tablet computer.

2 shows in a simplified representation the chassis with the side beams 12 and the front beam 13, as well as with a contact system 30 according to 1 , with two redundantly effective pairs 32, 34 and 42, 44 of contact elements per side (right-left) schematically from above, whereby for the sake of better clarity only the chassis with their spars with the contacting system 30 according to the invention are shown.

With common reference to the 1 and 2 The frame members 12, 14 are constructed as square tubes made of stainless steel of standard thickness. They are used to route the cables 36 from the contact system 30 to the tablet computer 20. This protects the cables 36 from damage.

In 2 Two contact pairs are shown on the right and left, thus providing redundancy for the contact. One is contact pair 34, 44, and the other is contact pair 32 and 42. Only one of the two pairs is required for proper operation; using both increases contact reliability.

The external contact elements 32 and 34 are strip-shaped and mounted on the outside of the beams 12. The contact element 34 extends around the rounded front edge on the right and left sides of the carriage, so that it can contact a mating contact element from the side and from the front.

On the inside of the uprights 12, internal contact elements 42, 44 are provided on the right and left of the chassis. When the next shopping cart is pushed in and the cart is placed in a nested position after shopping is finished, they are intended to establish and maintain mechanical and electrical contact with the corresponding contact elements 32 and 34 on the two outer sides of this next shopping cart. The internal contact element 42 on the upright 12 shown on the right makes contact with the contact 32, also on the right but located on the outside, of a cart of the same design and with the same contacting system that is pushed in next into the cart shown. The internal contact element 44 on the upright 12 shown on the right makes contact with the contact 34, also on the right but located on the outside and surrounding the front right edge, of a cart that is pushed in next into the cart shown.

In this example, the contact elements on the right side of the shopping cart are connected to the positive pole of the DC supply voltage. The contact elements on the left side of the shopping cart are connected to the negative pole of the DC supply voltage. The reverse is also possible.

In order to transfer the charging current from the shopping cart in front, which is already supplied with charging current, to the next cart pushed in, the contact elements 32, 34, 42 and 44 on the right side are connected to each other by contact lines (not shown).

Likewise, the contact elements 32, 34, and 42 and 44 on the left side are connected to each other by contact lines not shown.

Since the contact elements on the right side are connected to the positive pole of the DC voltage in this embodiment, and the contact elements on the left side are connected to its negative pole, there is no contact between the contact elements on the right and those on the left. Those skilled in the art will understand that only a single contact pair per side, i.e., 32 with 42, or 34 with 44, can be used if one is willing to forgo the redundancy of the contacts.

In the illustrated embodiment, the contact elements 32 and 34 are strips of chrome-plated copper, approximately 10 to 15 cm long and slightly less wide than the lateral height of the square beam 12, for example, 25 mm wide and 2 mm thick. They are each attached to the beam 12 by means of a non-conductive adhesive layer.

The cable 36 runs through the lower beam 12 and further through the connected vertical beam 14 upwards to a hollow upper cross beam (not shown), which also carries a holder for the tablet and in which the cable 36 is guided further to the tablet 20.

3 shows a simplified representation of two shopping carts pushed into each other, i.e. nested, according to 2 , but omitting the contact pairs 32, 42, whereby for the sake of clarity, only the chassis with the contacting systems 30 according to the invention are shown. The front outer contact elements 34 of the inserted carriage, which surround the front edges, always touch the front inner contact elements 44 of the preceding carriage, which are flexibly bent outwards by the insertion and thus, due to their mechanical flexibility, establish a mechanically stable electrical contact.

4 shows in simplified representation according to 3 the chassis of the first shopping cart, which is inserted into a contacting system of a base adapter 46, wherein the base adapter 46 is connected to a DC power supply and establishes an electrical contact with the contact elements 44 of the shopping cart shown in the drawing above, as already described above.

5 shows a shopping cart according to 3 with a holding device located on the floor in connection with the base adapter 4 in a schematic side view.

With common reference to the 4 and 5 In this position, the shopping cart is ready to be charged and to serve as a power source for the next cart pushed in. The supply voltage is connected to the power supply for the Tablet 20 ( 1 ) and requires a DC voltage. This is indicated by the symbols above in 4 The charging voltage is in the low range of 5V to 24 volts DC, typical for tablets.

The mechanical coupling of the first shopping cart with the base adapter 46 is effected in this embodiment only via the front bar 13 and the side bars 12. In other embodiments, this coupling can also be effected via the front side of the shopping cart. Preferably, the front wheels of the first cart of the row of carts to be nested are releasably locked in the fully inserted position, so that an accidental, incomplete insertion of the cart into the first cart can be ruled out. This is done in the example by a sleeper 48 screwed onto the floor of the carriage house, which is 5 exaggerated for improved clarity, and which must be rolled over by both front wheels to ensure stable mechanical and electrical contact.

The threshold 48 is preferably low enough that it can easily be rolled over by the customer during a normal adjustment procedure. It is preferably positioned so that electrical contact is established even if the trolley is pushed directly up to the threshold without rolling over it.

6 shows a nested row of shopping trolleys in which the third trolley from the top has not been fully pushed into the second and the desired electrical contact is not made at the front contact elements 34, 44, see detail on the right.

Due to a preferred redundant power connection, which can be established via the last trolley inserted into the trolley row after business hours, and which is described below in connection with the 14a , 14b , 14c described, it is still guaranteed that the cart that is not pushed in far enough and all the carts pushed in behind it are successfully electrically contacted and their batteries are charged.

7 The figure below shows a crookedly inserted carriage, which, thanks to its front contact elements 34 extending around the front edge of the chassis, still receives sufficient charging contact via contact pairs 34/44 at the front right. The same applies to the left side.

8a to 8e show several shapes for the design of the internal contact elements 42 or 44 from 2 - only the right side - as variants in schematic view, which create the flexibility of the contact element in different ways. Details on the attachment to the frame member 12 and the contact with the cable 36 are explained below.

The contact element 42 from 8a derives its flexibility solely from its shape and material properties. For example, this example shows an electrically conductive metal strip made of chrome-plated copper, 25 mm wide, approximately 15 cm long, and 1.5 mm thick.

The contact element 81 from 8b is constructed from a metal strip that transitions into the protruding part via a hinge 83. The protruding part derives its flexibility from an elongated compression spring 82, which is attached to it and to the bar 12 and pushes it away from the bar 12, thus holding it to the counter contact element. The contact element 81, for example, is an electrically conductive metal strip made of chrome-plated copper with a width of 25 mm, a protruding length of approximately 8 cm, and a thickness of 1.0 mm.

The contact element 84 from 8c is constructed from a metal strip, which also connects to the protruding part via a hinge. The protruding part derives its flexibility from a torsion spring 85, which pushes it away from the beam 12 and thus holds it to the counter contact element. The contact element 84, for example, is an electrically conductive metal strip made of chrome-plated copper with a width of 25 mm, a protruding length of approximately 8 cm, and a thickness of 1.0 mm.

The contact element 84 from 8d is constructed from a metal strip, which also hinges into the protruding part. The protruding part derives its flexibility from a pair of plastic-coated permanent magnets 87—additionally marked with a horseshoe symbol—which push it away from the beam 12 and thus hold it to the counter contact element. The contact element 86, for example, is an electrically conductive metal strip made of chrome-plated copper, 25 mm wide, approximately 8 cm protruding length, and 1.0 mm thick.

The contact element 88 from 8e It is a closed, electrically conductive metal strip made of chrome-plated copper, curved into an oval shape, 25 mm wide, with a long semi-axis of approximately 10 cm and a short semi-axis of approximately 5 cm, and a thickness of approximately 1.5 mm. Its flexibility comes solely from its shape and material properties.

9 shows an external contact element 34 guided around the front edge of 2 for the right side of the shopping cart schematically in several perspectives, omitting the contact to a socket of the cable inside the handlebar, where 9a a side view from the outside, 9b a side view from the inside, 9c a perspective view from the back outside top and 9d represents a top view.

In this embodiment, the contact element 34 is an elongated composite body adapted to the curvature of the rounded front edge of the chassis, consisting of an insulating body 90 made of electrically insulating material and a contact strip 92 made of aluminum or chrome-plated copper, which establishes the electrical contact.

In order to ensure that the contact elements 32, 34 remain robustly connected to the beam 12 even against accidental contact with the customers' shoes, the edges of the contact strips are preferably recessed in notch-like depressions on the insulating body 90, which prevents the edges from bending outwards over time and then tearing further, or from posing a risk of injury to the feet or legs of customers.

The insulating body 90 also serves the function of securely and robustly attaching the contact strip to the uprights 12, 13 of the chassis. In the example, it is made of a break-resistant polymer material, for example, ABS, with a thickness of approximately 7.5 mm and has a tab-like area 93 projecting beyond the longitudinal ends of the insulating body on both sides, each with a hole with which it can be screwed to the upright 12 or the front upright 13. The insulating body 90 preferably has a longitudinally extending base area 94, which has a shape that matches a corresponding curvature present in the upright 12, so that the contact element thus formed is robustly constructed as a whole and can be attached to the chassis of the shopping cart in a way that is resistant to external mechanical stress.

The insulating body 90 and the contact strip 93 are arranged in strips, with their longitudinal edges parallel to one another, and are glued together. The left-side contact element 34 has a structure analogous to the right-side one. The contacting of the cables located in the beam 12 will be discussed in more detail below.

10 shows an internal contact element 42 or 44 made of 2 for the right side of the shopping cart schematically in several perspectives, omitting the contact to a socket of the cable inside the handlebar, where 10a a side view of the back adjacent to the spar, 10b a view from behind, 10c a perspective view from the back outside top and 10d represents a top view.

The contact element 42, 44 in this embodiment is an elongated, strip-shaped composite body consisting of an insulating body 100 made of electrically insulating material and the actual metal body 102 made of aluminum or chrome-plated copper, which serves as the electrical contact and establishes the electrical contact, as is the case in connection with 8 was described.

The insulating body 100 also serves to securely and robustly attach the metal body 102 to the chassis spar 12. In this example, the insulating body 100 is made of a break-resistant polymer material, such as ABS or a comparable material with a thickness of approximately 5.0 mm, and has a hole on both sides of the longitudinal ends, with which it can be screwed to the spar 12.

The metal body 102 has two holes at the end region where it rests against the insulating body, through which two brass contact pins 106 pass. These pins lead to a cable piece that connects to a plug. The plug is located in a sufficiently large maintenance opening in the beam 12 and can be connected there to a suitable socket to establish the desired electrical contact.

The left-side contact element 42, 44 has a structure analogous to the right-side one. The contact to the cables located in the beam 12 will be discussed in more detail below.

11a shows an example of contacting an internal contact element 44, which is contacted and fastened by means of two screws made of electrically conductive material by means of matching nuts to an insulated contact lug 112 of a connecting cable piece, wherein the connecting cable piece contains two cables 114 and 116, wherein the cable 114 can be connected by a plug connection to the cable 36, which runs inside the spar and leads to the front, outer contact element 34 and wherein the other cable 116 leads to a plug connection, which on the one hand leads to the tablet and on the other hand to the other external contact 32 (cf. 2 ) leads.

11b shows an exemplary contacting of an external contact element 34 with the cable 114, which leads to a plug connection that leads to the tablet and to the internal contact 44.

12 shows an example of contact between an internal contact element and a cable running inside the spar, by means of a plug connection, as well as the contact for an external contact element, both on the right side in the assembled state for making contact and on the left side in the fully assembled state screwed to the spar 12 after making the electrical contacts.

The cables are laid in the spar 12 with a length surplus of approximately 20 cm, so that the connecting cable piece can easily be manually connected to the cable 36 outside the spar, and the electrically connected contact element can then be screwed tight to the outside of the spar.

13 shows two shopping carts according to the invention pushed into one another in a plan view of the chassis, in which, according to a variant of the present invention, the left and right bar 12 each has a first, small bulge 122 on its inner side, and the bar 12 also has a second small bulge 124 on its outer side. The bulges are stable and permanently robustly installed on the bar. They are dimensioned in such a way that during the pushing-in process, a slight mechanical resistance must be overcome when pushing the cart into the vehicle in front of it, and electrical contact is then maintained. The bulges 122, 124 engage with one another with their curves, as the 12 shows, they thereby form "locking lugs." The mechanical resistance when locking is intended to prevent the newly inserted carriage from rolling back on its own, for example on uneven terrain or due to careless handling, which could lead to the loss of the previously established electrical contact. The bulges 122, 124 can be made as buffer bodies from a slightly flexible plastic, for example from a somewhat softer ABS, and can be glued to the rail or screwed to it, with the screws countersunk into the material if necessary. The surface of the buffer bodies is preferably smooth.

Instead of a second locking lug, a concavity can also be provided in the bars 12, preferably on their outer sides, into which the locking lugs on the right and left engage. The material of the individual locking lugs should then be slightly less flexible to ensure the same locking effect.

14a shows a "dummy" shopping trolley frame 140 provided according to the invention in a schematic view from above, which has an additional power connection with a connecting cable 144 installed on the shopping trolley housing and intended for the last trolley 142 of a nested row, in a schematic partial view from above in the nested state, 14b shows the “dummy” shopping cart frame 140 schematically in perspective from the front above without cables, and 14c shows the “dummy” shopping cart frame schematically from above with connecting cable 144.

The “dummy” shopping cart frame 140 can be moved to the last shopping cart in a nested row of carts after the store closes and can be connected with its connecting cable 144 to a second, redundant DC power supply provided stationary in the cart house.

The "dummy" shopping cart frame 140 has the same external contact elements 34 as described above and supplies power to the internal contact elements 44 of the last cart 142 in the row. Thus, if there is no electrical contact between two shopping carts at a leak point in the row that is difficult for staff to detect, this last cart 142 can supply power to the carts in front of it up to the leak point, and the associated batteries can thus be charged. If there is no leak point at all, the contacts 34 of the dummy 140 and the contacts 44 of the last cart are at the same voltage potential, and the additional power connection is simply not used, but it cannot cause any damage.

15 shows a shopping cart equipped according to the invention with a cable duct 140, which leads from the lower hollow bar 12 to a not shown upper, hollow crossbar, which also carries a holder for the tablet, and in which the cable 36 is guided further to the tablet 20. The cable duct 140 is also present on the left side of the cart. It is preferably used for shopping carts that do not have a hollow, double-sided vertical bar according to 1 have, but only a stable wire frame that connects between the lower pole 12 and the handle bar and/or the shopping cart. The cable duct 140 is preferably made of a hollow aluminum tube that follows the contour of the shopping cart as closely as possible. For this reason, corresponding bending points are provided in the tube at the bends 142, 144. The attachment to the wire frame of the cart can be made with suitable, irreversible click connections or other suitable connecting elements commonly used in the art in order to prevent manipulation or wear by customers. The cable duct 140, when the cable is lying in it, can be pushed into a separate opening provided in the pole 12 (not shown) so that the cable is not freely visible on the surface and cannot be manipulated.

16 shows a shopping cart equipped according to the invention, entirely without hollow uprights, with a cable duct 160 that runs from the foremost contact elements 34 to the tablet. Its upper, vertical part is constructed and secured as described above, and its lower part 162 runs externally on the underside of the chassis so that it is exposed to as few mechanical stresses as possible that occur when the carts are pushed together. In its lower part 162, the cable duct has a cross-section large enough to accommodate the previously described cables, including excess length and plugs. The external con Contact elements 34 are secured to the outside of the wire frame in a torsion-proof manner and have no protruding corners or edges. The internal contact elements are secured to the inside of the wire frame in a torsion-proof manner.

17 shows a schematic side view of a shopping cart equipped according to the invention in which the contact elements 34, 44 are attached to the bottom of the shopping cart.

18 shows a schematic top view of the shopping cart from 17 .

With common reference to the 17 and 18 In this exemplary embodiment, the right- and left-hand contact elements 34 are each an elongated, strip-shaped composite body consisting of an insulating body made of electrically insulating material and a contact strip made of aluminum or chrome-plated copper, which establishes the electrical contact, analogously to the 9a -d, only in planar form. The internal contact elements 44 are constructed as in 10 described. In the example shown, however, the contact elements 34, 44 are located directly opposite each other and not longitudinally offset as in the example from 2 . The material of the basket wall lies between them. The contact to each other and to the cable leading to the tablet 20 takes place in a somewhat more voluminous contact section 172 of the cable duct, which is connected to the actual cable duct 170, which is also shown schematically, and contains the necessary plug connections. The cable duct 170 is preferably arranged in the interior of the basket. As described above, it is preferably made of plastic or metal. The internal contact elements 44 have rounded edges and are preferably so strong that it is impossible for a user to cut themselves on them. They preferably have a bent shape at a freely projecting end section, as in 8a illustrated or have a longitudinally oval closed shape, as in connection with 8e As explained, so that the shape is robust enough and is not altered by the goods placed in the shopping cart. A non-conductive plastic plate 174 is preferably arranged beneath the internal contacts, which is large enough to prevent direct contact between contact element 44 and the material of the shopping cart itself. This ensures that no leakage current flows through the shopping cart during charging.

When the shopping carts constructed in this way are pushed into one another, the front section of the shopping cart of the newly inserted cart protrudes into the interior of the cart in front of it, as the rear wall of the shopping cart is pivoted upwards as usual. The contact pairs 34, 44 are arranged on both sides in such a way that the outer contact elements 34 of the newly inserted cart and the inner contact elements 44 of the cart in front of them are in permanent contact over the desired surface of the inner contact element 44.

The coupling of the first carriage to the base adapter 46, see 4 with description, is carried out analogously with a base adapter, which is structurally adapted to the changed height of the contacts.

19 shows a schematic side view of a shopping cart equipped according to the invention, in which the contact elements are attached to the top of the shopping cart. Here, the cable duct 170 runs approximately below the upper edge of the shopping cart into its interior.

20 shows a schematic side view of a shopping cart equipped according to the invention without a lower storage level, with a chassis that has four bars running diagonally downwards from the rear of the shopping cart - also referred to here as "slanted bars" - which connect to the respective rollers, and in which the contact elements are attached to the bottom of the shopping cart. For this purpose, reference can be made to the description of 17 and 18 since the contacting system is completely independent of the chassis, as long as it is ensured that the contact elements 34, 44 touch each other sufficiently closely and permanently during nesting.

With reference to the 21 to 23f A further variant for shopping carts without a lower shelf is described, in which the four wheels of the cart are individually mounted on slanted downward bars, referred to as slanted bars 210. Here, the contact elements according to the invention are attached to the cart in the area of the front rollers:

21 shows a schematic side view of a shopping cart equipped according to the invention without a lower storage level, with a chassis that has four inclined beams running diagonally downwards from the shopping cart, which connect to the rollers, and in which the contact elements 34, 44 are attached to the two front inclined beams 210 above the rollers. The cable is guided in a cable duct 170 similar to the one shown above in 17 described.

22 shows the shopping cart 21 in a schematic, with only the outlines of the Basket exposed view from above with the contact elements 34, 44.

The inwardly directed contact elements 34 are strip-shaped and are attached, preferably glued, to rigid, self-supporting, elongated, strip-shaped plastic supports 212. The plastic support, in turn, is attached to the inclined beam 210 and projects freely to the rear. The outwardly directed contact elements 44 are also attached to the inclined beam 210, preferably close to the beam 210 on its outwardly facing surface at the same height above the ground, so that the corresponding contact pairs of nested carriages touch each other, see 23a .

23a shows two shopping carts from 21 or 22 , fully nested, in a schematic top view with only the outline of the basket exposed. The contact elements 34 and 44 are shaped such that they already touch each other during the nesting process, well before a provided mechanical stop that defines the fully nested position. They remain in mechanical and electrical contact all the way to the stop, with the outwardly projecting ends 214 of the plastic supports 212 being pushed further and further outward. The contact elements 34 and 44 continue to maintain mechanical and electrical contact in the fully nested position of the carriages.

23b To further clarify the attachment of the contact elements 34 and 44, a section of the right front inclined beam 210 in the direction of travel with the contact pairs 34, 44 in a schematic side view from an angle from the outside front and above.

23c shows the fastening point of the contact pairs 34, 44 from the front in a position about 10 cm above the holder for the roller.

23d shows a schematic, side view from the outside of the inclined beam with the contact pairs 34, 44.

23e shows a schematic view from above of the front inclined beam 210 on the right in the direction of travel with the contact pairs 34, 44.

23f shows the excerpt from 23b from the inside.

In the exemplary embodiment, the fastening of the plastic carrier 212 for the inwardly directed contact elements 34 is provided by a sleeve 230 that surrounds the inclined beam 210 and is screwed to the inclined beam 210. The sleeve 230 has receptacles on its outer side for the outwardly directed contact elements 44. The sleeve 230 and the plastic carrier 212 are manufactured as injection-molded parts from a suitable plastic that has the required mechanical robustness and is UV-stable.

The cables are connected in the inclined beam 210, provided it is hollow, in the same way as described above. If the inclined beam is not hollow or has a too small cross-section, the cables run upwards in a cable duct along the two inclined beams 210, as described in 17 or 21 shown and described there.

24 shows a side view of a shopping cart with a pivotable storage level 240 arranged below the shopping cart, in which two contact pairs arranged next to one another with sufficient lateral distance from one another - only one of which is shown in the figure - are arranged on the lower storage level, each contact pair having a first, upwardly directed contact element 241 and a second downwardly directed contact element 242 with the electrical connections as described above.

The lower storage level consists of a wire frame with four longitudinal struts running in the direction of travel and a few cross struts connected to them made of thick aluminum wire, about 8 mm thick, as is often found in the state of the art.

The two downward-facing contact elements 242 are analogous to those 9 The contact elements described are constructed as a composite body, but with an elongated shape of approximately 30 cm in length and 5 cm in width, again consisting of an insulating body made of electrically insulating material and a contact strip made of aluminum or chrome-plated copper, which establishes the electrical contact.

The downward-facing contact elements 242 are secured with their insulating bodies to the two central longitudinal struts of the storage level 240 in a rotationally secure manner, for example, by screwing. They have a free distance between them of approximately 8 to 10 cm, depending on the distance between the two central longitudinal struts. They run parallel to each other.

In this embodiment, the two upwardly directed contact elements 241 are located in the area of the approximately 40 cm long front edge of the Storage level 240 and are fixed there in its central area with a lateral distance from each other that corresponds to that of the contact elements 242. For details of the contacts, the wiring of the electrical lines, and the routing in a cable duct, reference can be made to the description above. Preferably, the cables are routed through the front beam and the two side beams, or, if no hollow beams are present, in corresponding cable ducts. Thus, the end section 243, which extends freely upwards during nesting (see 25 ) of the lower storage level without any cable.

25 shows two nested shopping carts according to 24 in a side view, showing the contact between the upward-facing contact element 241 of the rear (left-shown) shopping cart and the downward-facing contact element 242 of the front shopping cart. Preferably, the upward-facing contact element 241 is slightly obliquely flattened at its front, upward-facing edge so that the electrically effective contact area with its downward-facing mating contact element 242 is as large as possible.

Advantageously, in this embodiment, in which the contact strip of the downwardly directed contact element 242 is approximately 30 cm long, the mechanical and electrical contact is maintained even when the carriages are pushed into one another very messily, even when they are a considerable distance apart in the direction of travel, since the weight of the pivoting storage level 240 presses the upper contact element onto the lower one in practically any position.

26 shows a schematic side view of a shopping cart with a shopping basket, with two contact pairs attached to the basket bottom with sufficient lateral distance from each other - only one contact pair is shown because of the side view - each contact pair having a first, upwardly directed contact element 261 and a second downwardly directed contact element 262.

27 shows two nested shopping carts according to 26 in a side view, showing the contact between the upward-facing contact element of the rear shopping cart (shown on the left) and the downward-facing contact element of the front shopping cart.

With common reference to 26 and 27 The basket base 260 consists of a relatively fine-meshed wire frame made of aluminum wire, about 3 mm thick, as is often found in the state of the art.

The two downward-facing contact elements 262 are analogous to those 9 The contact elements described are constructed as a composite body, but with an elongated shape of approximately 20 cm in length and 5 cm in width, again consisting of an insulating body made of electrically insulating material and a contact strip made of aluminum or chrome-plated copper, which establishes the electrical contact.

The two downward-facing contact elements 262 are attached, for example, screwed, with their insulating bodies to the underside of the basket base in the front area symmetrically to the longitudinal axis. The contact elements 262 run parallel to each other and have a free distance between them of approximately 10 cm.

The two upward-facing contact elements 261 are approximately the same length and width as the downward-facing contact elements 262 and, in this exemplary embodiment, are arranged slightly in front of the center of the basket base and secured there with a lateral distance from one another that corresponds to that of the contact elements 262. For details of the contacts, the wiring of the electrical cables, and the routing in a cable duct, please refer to the description above. The upward-facing contact elements 261 are positioned such that they come into contact with the downward-facing contact elements of the front vehicle over as large a surface as possible when pushed into one another.

To prevent the contact elements from jamming together in the nested position when the carriages are pushed into each other up to their stop as provided in the prior art, at least one of the two contact elements, preferably the one facing downwards, is spring-mounted or has a pre-tension formed by the shape or suspension of the contact element. Here, too, reference can be made to the description above in connection with 8 , in particular 8e The preload ensures that the contact pressure between the contact surfaces remains within a predefined range, even when the carriages are pushed into each other until they reach their mechanical stop, whether perfectly aligned or with a deviation of several degrees.

28 shows a schematic side view of a shopping trolley with a shopping basket, with two contact elements 281 attached to the upper basket edge 280 - whereby because of the side view only one contact element is shown - and two contact elements 282 attached to the pivoting basket rear wall 285 - whereby because of the side view also only one contact element is shown - which together form a contact pair and are electrically connected to each other.

29 shows two nested shopping carts according to 28 in a side view, showing the contact between the upwardly directed contact element on the basket edge of the rear shopping cart (shown on the left) and the downwardly directed contact element on the pivoting basket back wall of the front shopping cart.

With common reference to the 28 and 29 The pivoting basket back wall 280 also consists of a wire frame, constructed in a grid-like manner, made of aluminum wire with a thickness of about 3 mm, with its edge 286 being formed by a slightly stronger wire.

The two contact elements 282 facing downwards in the nested position are analogous to the 9 The contact elements described are constructed as a composite body, but with an elongated shape of approximately 10 cm in length and 5 cm in width, again consisting of an insulating body made of electrically insulating material and a contact strip made of aluminum or chrome-plated copper, which establishes the electrical contact.

The downward-facing contact elements 282 are secured with their insulating bodies to the two outer right and left struts of the basket rear wall 285 in a rotationally secure manner, for example, by screwing. They extend slightly diagonally to each other, at the same angle as the right and left upper basket edges converge.

In this embodiment, the two upward-facing contact elements 281 are arranged in the front third of the right- and left-hand edges 280 of the basket and are secured there in a rotationally secure manner. For details of the contacts, the wiring of the electrical cables, and the routing in a cable duct, please refer to the description above. Preferably, the connecting cables between the contact elements of a pair are routed along the top edge of the basket and then along the outer edge of the pivoting rear wall of the basket in corresponding cable ducts.

Advantageously, in this embodiment, in which the contact strip of the upwardly directed contact element 281 is approximately 30 cm long, the mechanical and electrical contact is maintained even when the trolleys are pushed into each other very messily, even when they are a considerable distance apart in the direction of travel, since the weight of the pivoting rear wall 280 of the basket presses the upper contact element onto the lower one in practically any position.

30 shows a schematic side view of a shopping cart with an electric motor-driven fifth wheel 301 and a battery 303, which is also supplied with power next to the tablet 20 by the contacting system according to the invention, which has been omitted for reasons of improved clarity.

31 shows the shopping cart 30 exposed without basket in a schematic view from above.

The battery 303 is attached to a front cross member of the chassis. It is supplied with power by the connection cables of the contacting system (not shown) located on the right and left sides of the shopping cart. The battery is connected to the drive motor on the drive roller via a supply cable 305. The exemplary embodiment shows that even a battery that is not part of the tablet 20 can be supplied with charging current via the contacting system according to the invention, since its attachment does not interfere with the attachment and functioning of the contacting system according to the invention, and the contacting system itself is also fundamentally suitable for supplying a correspondingly higher charging capacity with the aforementioned supply voltages.

Although the present invention has been described above using a preferred embodiment, it is not limited thereto but can be modified in many ways.

In one variant, the outwardly directed contact elements are each designed to be flexible, such that they exert a certain permanent pressure on their respective counter-contact element, namely the inwardly directed contact elements, when in contact in the nested state. The flexibility can be achieved by the means mentioned above, depending on the shape, material thickness and size of the outwardly directed contact elements used. Advantageously, the outwardly directed contact elements do not protrude beyond the outer contour of the lower beams 12, but are mounted, for example, below the beams. However, it is also possible for the inwardly directed contact elements to be designed to be flexible and to adapt accordingly to the outwardly directed Contact elements in the nested state exert a permanent, certain pressure during their contact.

In another variant, in addition to the front contact elements 34 and 44, the side contact elements 32 and 42 are also installed. This can be advantageous if you want to increase the redundancy of the contacts and thus the reliability of the contact.

In one variant of the present invention, the cart according to the invention, and specifically the shopping cart, is equipped with a radio module for a beacon connection. This can be implemented via the Wi-Fi of the associated store or via a Wi-Fi-independent wireless radio connection between each cart and a stationary beacon base station located in a cart shed. As soon as the cart is pushed into the cart shed, the base station registers this due to the spatial proximity to the base station, and a beacon-based control of the charge level of the tablet computer's battery is activated. The charge level of the battery to be charged is queried and displayed, for example, via a multi-color LED. Green can mean "sufficiently charged," red or the absence of the LED can mean "battery needs to be charged," and yellow can mean "charging not absolutely necessary." This ensures that store staff can determine at a glance whether a shopping cart located in a nested row needs to be charged immediately or at a later time. This “charging status LED” is preferably mounted separately near the top of the Tablet 20 or integrated into the tablet, for example on its left edge.

In another variant equipped with beacon technology, which can optionally include the aforementioned variant, a so-called "contact status LED" is provided on the shopping cart. This can also be a multi-color LED. This LED indicates the status "can be charged" or "cannot be charged." It is wired to glow green when current is flowing across both charging contacts (for PLUS and MINUS) of a cart in a nested row, meaning the battery can be charged if it is properly nested in the cart housing. The LED glows red or not at all when no charging current is flowing, for example because the cart was pushed in crookedly and only one pair of charging contacts is touching, or because it was not pushed far enough into the cart in front of it. This "contact status LED" is preferably mounted separately at the top near the tablet 20 or integrated into the tablet, for example on its right edge. In this example, it is connected in parallel to the shopping cart's charging current and therefore receives power when the cart is being charged - even if the charging current is very low and the cart's battery is already almost fully charged. This has the advantage that store staff, for example after closing time, only have to briefly look at the nested rows of carts in a cart bay to check the contacts. As soon as they see a red LED light up on the right edge of the tablet, they know that the contact there is broken. They can then, standing at the end of the row, push the last cart in a little, along with the carts in front of it, and if necessary, touch the cart with the poor contact individually and adjust it so that it makes contact.

If the beacon is connected to the store's Wi-Fi, this query of the contact status can then also be used to send a message to a pre-programmed mobile number of an employee, stating that a manual check of a specific car garage should be carried out.

In another variant of the present invention, equipped with beacon technology, the shopping carts are equipped with a beacon, and the entrance area of a store is equipped with several stationary beacons. If a customer then drives through the entrance area in the wrong direction, they pass from one stationary beacon to the next—albeit in an unexpected direction. This can be easily registered and monitored accordingly. For example, a warning LED on the affected shopping cart can be switched to flashing mode and/or an acoustic alarm can be triggered if the customer has crossed the entrance barrier in the wrong direction.

In one variant of the present invention, a retrofit kit is disclosed: The part of the cable duct 162 intended for the lower area of the shopping cart, together with its cables, cable connecting elements, and the contact elements 32, 34, as well as 42 and 44, or the other described contact elements, are manufactured as a prefabricated set, ready for attachment to the chassis of a shopping cart. This allows existing shopping carts constructed solely from a wire frame to be easily retrofitted. The connection to a tablet 20 can then be individually manufactured, depending on the design of the rear frame and the handlebar, as well as a suitable holder for the tablet, of the shopping cart to be retrofitted.

Finally, the features of the subclaims can essentially be freely combined with each other and not be combined with each other by the order in which they appear in the claims, provided that they are independent of each other.

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10 2022 103 520 A1 [0003]
• EP 3 252 913 B1 [0004]
• EP 3 644 474 A1 [0005]

Claims (17)

A pushable cart, in particular a shopping cart, with a contacting system, wherein the contacting system comprises: a first contact pair with at least two contact elements for a first connection pole of an electrical charging voltage; a second contact pair with at least two contact elements for a second connection pole of the electrical charging voltage; wherein the first and second contact pairs are configured such that: by pushing the pushable cart into a second, identically constructed cart with a second, identically constructed contacting system, at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair establishes an electrically effective contact with a respective mating contact element of the second cart; wherein at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair are configured and/or arranged such that: at least during part of the pushing-in process, a sliding and/or rolling contact is established between the contact elements and the mating contact elements; and/or a fixed contact is established when fully inserted. Pushable trolley to Claim 1 , wherein the contacting system is configured to supply power to the trolley, preferably to supply power to a battery of the pushable trolley and/or an electrical device connected to the battery. Push-cart according to one of the Claims 1 or 2 , wherein at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair is arranged such that it serves as a counter-contact element for a third, identical carriage when the third, identical carriage is inserted into the carriage. Push-cart according to one of the Claims 1 - 3 , wherein: at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair is directed towards the inside of the pushable carriage; at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair is directed towards the outside of the pushable carriage; wherein the contact element directed towards the outside of the pushable carriage is conductively connected to the contact element of the respective contact pair directed towards the inside of the pushable carriage. Push-cart according to one of the Claims 1 - 4 , wherein: the contact elements of the first contact pair are mounted on a left side of the carriage, preferably on a chassis of the carriage, and/or the contact elements of the second contact pair are mounted on a right side of the carriage, preferably on the chassis; and/or the contact elements of the first contact pair are mounted on a left front edge of the carriage, preferably on the chassis of the carriage, and/or the contact elements of the second contact pair are mounted on a right front edge of the carriage, preferably on the chassis. Pushable trolley to Claim 4 or Claim 5 with reference to Claim 4 , wherein: the contact elements directed towards the outside of the pushable trolley are each formed around a front edge of the trolley so as to form part of a left or right side and part of a front side of a chassis and/or a basket of the trolley. Push-cart according to one of the Claims 1 - 6 , wherein the first and second contact pairs are arranged such that: at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair is directed upwards; at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair is directed downwards; wherein the contact elements of a contact pair are each conductively connected to one another. Pushable trolley to Claim 7 , wherein: the trolley has a, preferably pivotable, storage level, and the first and/or second contact pair are arranged on the storage level; and/or the trolley has a shopping basket, and the first and/or second contact pair are arranged on the shopping basket. Push-cart according to one of the Claims 1 - 8 , wherein at least one of the contact elements has a contact surface, preferably a contact strip with a predetermined length and width. Push-cart according to one of the Claims 1 - 9 , wherein at least one section of at least one of the contact elements of the first contact pair is designed to be flexible and/or at least one section of at least one of the contact elements of the second contact pair is designed to be flexible such that: the at least one flexible section exerts permanent pressure on the respective counter-contact element in the at least partially inserted state; wherein the at least one flexible section is preferably directed inwards and/or downwards. Push-cart according to one of the Claims 1 - 10 with a system for maintaining contact, wherein: the system for maintaining contact comprises at least a first and at least a second system element such that: a positive connection is established between the at least one first system element of the carriage and a second counter-system element of the second, identically constructed carriage when the second carriage is pushed into the first carriage and the electrically effective contact is established in the process. Pushable trolley to Claim 11 , wherein the carriage comprises a chassis with at least one spar, wherein: a male system element is provided on an inner side of the spar; a female system element is provided on an outer side of the spar. Pushable trolley to Claim 11 or 12 , wherein the system for maintaining contact is provided by shaping matching contact elements in contact with one another. Push-cart according to one of the Claims 1 - 13 , wherein: the carriage comprises a power connector which is electrically connected to the contacting system. Device for insertion into a rearmost carriage of a nested row of pushable carriages, the device comprising a contacting system, wherein: the contacting system contains contact elements such that: by inserting the device into a carriage according to Claim 1 an electrical contact with the respective counter-contact elements of the carriage after Claim 1 can be produced. A contact system for mounting on a push-pull cart, comprising: a first contact pair with at least two contact elements for a first connection pole of an electrical charging voltage; a second contact pair with at least two contact elements for a second connection pole of the electrical charging voltage; wherein the first and second contact pairs are configured such that: the first and second contact pairs each have at least two contact elements; and by inserting the push-pull cart into a second, identically constructed cart with a second, identically constructed contact system, at least one of the contact elements of the first contact pair and at least one of the contact elements of the second contact pair establishes an electrically effective contact with a respective counter-contact element of the second cart. Retrofit kit for a push-along trolley, especially a shopping trolley, with a contact system according to Claim 16 .