ES1309718U - Partially buried set for bicycle parking (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

System (20) comprising a partially buried assembly (1) for parking bicycles, comprising a container (2) provided with a plurality of lockers (T) for bicycles and a lifting and lowering mechanism to pass the container through. (2) of lockers between an upper position and a lower position, characterized in that the lifting and lowering mechanism is fixed to a lower portion of the container (2), and that a difference in height between the lower position and the upper position is less than a total height of the container (2). (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Partially buried bicycle parking set

OBJECT OF THE INVENTION

The present invention falls within the field of sustainable mobility, in particular mobility using light vehicles such as bicycles, scooters or the like.

The object of the present invention is a system comprising a partially buried infrastructure designed for parking bicycles, scooters or the like.

BACKGROUND OF THE INVENTION

New, more sustainable forms of mobility are currently on the rise, allowing users to move around city centres without emitting greenhouse gases. These forms of mobility include light vehicles such as bicycles and scooters. The use of these types of vehicles is already widespread, so the number of bicycles and scooters parked in city streets and squares is increasing.

In order to prevent bicycles and scooters from becoming an obstacle to pedestrian movement, specific parking areas for these vehicles have been set up throughout the cities. In the case of scooters, these parking areas are basically just spaces delimited by lines, while for bicycles, they are limited to structures, usually made of metal, so that users can lock their bicycles to them using locks and/or chains.

While these types of parking areas solve the problem of preventing these vehicles from obstructing pedestrian traffic, the problem of vehicle safety remains unsolved. As a result, thousands of bicycles are stolen every year throughout Spanish cities.

To solve this problem, some car parks have been proposed with lockers designed to accommodate a bicycle or scooter. As an example, the present applicant is the holder of the utility model ES1259381, which describes a module of this type designed to be installed on the surface in any suitable location.

However, it is sometimes difficult to find free locations for the installation of this type of system. For this reason, the applicant subsequently developed the system described in document ES1237100. This system comprises an assembly similar to the previous one, although in this case equipped with a mechanism that allows it to be completely buried until its roof or highest surface is flush with the ground surface. That is, the equipment described in document ES1237100 can alternate between an upper position, in which it is above ground level and, therefore, allows bicycles to be inserted and removed from the corresponding lockers, and a lower position, where it is completely buried and invisible to passers-by. This system solves the space problems and, in addition, has the advantage of greater security against theft and vandalism. It is also important to mention that the mechanism that allows the container that houses the bicycles to be buried or removed in document ES1237100 does not use hydraulic cylinders, which have various disadvantages. For example, it is difficult to ensure that they rise in sync due to the difference in weight distribution, it requires more maintenance, and it is also dirtier due to the hydraulic fluid.

In any case, the lifting/lowering mechanism of the buried locker container in document P1237100 is still open to improvement. Furthermore, it has been found that complete burial of the container may be inconvenient in some contexts.

DESCRIPTION OF THE INVENTION

The inventors of the present application have developed a system comprising a partially buried assembly, i.e. an assembly in which the locker container only descends into a pit a certain distance less than its own height. This configuration is advantageous because the locker container remains visible to cyclists who may need it and, at the same time, greatly reduces the likelihood of theft or vandalism. In addition, it allows it to be used as a support or to sit on when it is in its lower position.

In addition, this new system differs from the system described in document ES1237100 in that the assembly's ascent-descent mechanism is improved and also integrated with the locker container. Indeed, in document ES1237100, the installation of the system requires a step-by-step assembly of the different elements that make up the ascent-descent mechanism inside the pit, subsequently the arrangement of the locker container on said ascent-descent mechanism, and finally the connection of the container with the ascent-descent mechanism.

In contrast, in the present invention the ascent-descent mechanism is completely integrated, i.e. fixed to the locker container itself. In this way, the installation of the assembly is extremely quick and simple, since it essentially only requires placing said assembly in the previously made pit. Furthermore, as can be seen throughout this report, the ascent-descent mechanism has a completely different structure from that described in document ES1237100.

The present invention is directed to a system provided with a partially buried assembly for parking bicycles. This assembly comprises a container provided with a plurality of bicycle lockers and a lifting and lowering mechanism for moving said container between an upper position and a lower position.

In principle, the locker container is similar to that described in document ES1237100. It is a container with an essentially parallelepiped shape and a rectangular horizontal section. The container has a front side where the doors that give access to each of the lockers are located, a closed rear side, two end faces that are also closed, a lower base and an upper cover. In this document, the direction parallel to the longest side of the rectangular horizontal section will be referred to as the “longitudinal direction”. As mentioned, the lifting and lowering mechanism allows the container to be raised or lowered between a lower position and an upper position.

So far, a system similar to that of document ES1237100 has been described. However, the system of the present invention differs from that essentially for two reasons.

Firstly, the lifting/lowering mechanism is fixed to a lower portion of the container. That is, in the system of the invention, the assembly formed by the container and the lifting/lowering mechanism is constituted as a single element. This is very advantageous in relation to the system described in document ES1237100 since, as will be described in greater detail later in this document, the installation of a system of this type is extremely fast: it is basically enough to introduce the assembly into a pit sized for this purpose and perform a few additional tasks for the installation to be put into use.

Secondly, a height difference between the lower position and the upper position is less than a total height of the container. Thus, when the assembly of the invention is housed in a suitably sized pit, the container is not completely buried inside it when it is in the lower position. That is, in the lower position a relevant part of the height of the container protrudes above the ground height, for example, half or a third. This is advantageous in relation to a complete burial as described in document ES1237100, since it leaves the container partially visible even in the lower position, thus facilitating its location by cyclists who need it. In addition, the portion of the container that protrudes from the ground in the lower position provides a platform that can be used for other uses, such as for sitting or leaning. Partial burial also allows reducing the excavation depth, reducing the probability of encountering city services or to overcome the water table in coastal areas. In addition, the lifting stroke is reduced, meaning users have to wait less time to access their locker.

In principle, the lifting/lowering mechanism of the system of the present invention can be of any type as long as the travel is less than the total height of the container when it is in its natural position, in order to ensure that it is only half buried when it is in the lower position. For example, said height difference can be between 30% and 60% of the total height of the container.

In a particularly preferred embodiment of the system of the present invention, the lifting and lowering mechanism essentially comprises the following elements.

a) Fixed structure

The fixed structure is configured to rest on a horizontal surface, normally the bottom of the pit where the assembly of the present invention will be installed. In addition, the fixed structure comprises a vertical prismatic cavity whose horizontal section has larger dimensions than the container.

The fixed structure may have a cage-like shape formed by a set of beams or bars that form a rectangular parallelepiped similar to the horizontal section of the container but with a size, i.e. length and width, slightly larger than the dimensions of said horizontal section of the container. The space inside said parallelepiped-shaped structure will be essentially hollow, thus forming the prismatic cavity through which the locker container can move vertically between the lower position and the upper position. The number, dimensions, and orientation of the different bars or beams that make up the fixed structure may vary depending on the needs of each application and, naturally, provided that it ensures sufficient strength to support the weight of the locker container loaded with bicycles.

According to a preferred embodiment of the invention, the fixed structure comprises feet for resting on the horizontal surface. These may be, for example, four feet located near the four corners of the fixed structure. Each foot may also be fixed to the fixed structure by means of a rod, so that it is adjustable in height in order to allow adequate levelling of the fixed structure on the bottom of the pit in which it will be installed. Furthermore, as will be seen later in this document, said feet may support the 4 chain branches from which the platform is suspended.

b) Mobile structure

The movable structure is rigidly attached to a lower portion of the container, such that both constitute a single rigid solid. The movable structure and the container are vertically slidably attached to the fixed structure, such that said container and said movable structure can ascend or descend along said prismatic cavity between the upper and lower positions.

The mobile structure may consist essentially of a set of bars or beams that essentially form a plane with floor dimensions similar to those of the container. Once this mobile structure is fixed to the lower face of the container, the assembly formed by the mobile structure and the container can move vertically between the upper and lower positions.

The mobile structure, as well as the locker container, may additionally comprise guide elements to ensure a correct vertical movement of the assembly formed by the mobile structure and the container, cooperating not only to ensure that they follow an appropriate vertical path but also to ensure that the container remains level. For example, one or both elements may have skates or wheels with a horizontal axis that slide or roll along tracks of the fixed structure.

c) Means of operation

The drive means are connected between the fixed structure and the mobile structure to move said fixed structure, together with the container, between the lower position and the upper position.

In principle, the drive means can be of any type as long as they have sufficient power to move the fixed structure and the container from one position to another and also ensure a level vertical movement of the container. In this sense, the term "level" refers to the fact that the base of the container must remain horizontal at all times, since otherwise the bicycles or other items stored in the lockers could move, fall or tip over.

According to a particularly preferred embodiment of the system of the invention, the actuating means essentially comprise the following elements:

c1) Drive motor

The drive motor is attached to the movable frame, and has a shaft that is mechanically connected to two rotating shafts connected to the movable frame and oriented in a longitudinal direction, which respectively extend to vertical end planes located at ends of the movable frame. The connection between the drive motor and the rotating shafts is configured such that, when said motor is actuated, it rotates both shafts in the same direction. In addition, the end of each shaft is connected to a pair of drive gears so as to rotate them in opposite directions.

The rotating shafts could be aligned and located in any position, although preferably they are located, like the motor, under the container and essentially centered in relation to the transverse direction of said container. That is, the motor can be fixed to a bar or beam of the mobile structure under the container, for example, centered both longitudinally and transversely. In turn, the rotating shafts, which as mentioned are oriented in the longitudinal direction and have a length similar to the length of the container, can be located approximately at the same distance from both lateral faces of the container. The drive gears are thus located in the respective end planes next to each other, with one drive gear of each pair rotating in the opposite direction to the other drive gear of said pair.

c2) Lifting and lowering chains

These are two pairs of lifting and lowering chains respectively located on end planes. The end planes are parallel to the end faces of the locker container, and each of them is located near one of the ends of said locker container. More particularly, each chain has an upper end fixed to a fixed point, an intermediate point engaged in a drive sprocket driven by one of the rotating shafts, and a lower end connected to a counterweight that keeps said chain taut. Thus, the mobile structure and the container are suspended from an upper section of the chain between the fixed point and the sprocket. Naturally, in order to allow the container to reach a given upper position, the fixed point to which the upper end of the chain is fixed must be located at least at said height or higher.

Thanks to this combination, when the drive motor is activated in an upward direction, the upper section of each chain is simultaneously retracted, causing the container to rise levelly to the upper position. Alternatively, when the drive motor is activated in a downward direction, the upper section of each chain is simultaneously released, causing the container to lower levelly to the lower position. The coordination between the collection or release of the four chains that make up the two pairs is ensured thanks to the fact that both rotating shafts are moved in a synchronized manner by a single motor and because, as will be seen more clearly in the figures attached to this document, the four chains are engaged with the four gear wheels driven by said rotating shafts two by two. In addition, each pair of driving gear wheels are synchronized by being connected to the same shaft, one of them being connected through a straight-toothed gear that reverses its direction of rotation in relation to the other driving gear wheel of the same pair.

The path of the lifting and lowering chains can be configured in different ways as long as they can carry out the functions described above. For example, in a particularly preferred embodiment of the invention, a first idler sprocket is used which guides the upper section of each chain between the fixed point and the drive sprocket, and a second idler sprocket is used which guides a lower section of each chain between the drive sprocket and the connection to the counterweight.

In principle, different counterweights could be used to ensure that the lower sections of the lifting and lowering chains are kept taut at all times. However, according to a particularly preferred embodiment of the present invention, two beam-shaped counterweights are used, each of which is essentially contained in one of the said end planes containing each pair of chains. Thus, the lower end of one chain of each pair of chains is connected to one of the ends of said counterweight.

Thanks to this configuration, the assembly can be installed in an extremely simple manner. Since the container and the lifting and lowering mechanism are factory-joined, to install the assembly of the present invention it is sufficient to lift it with a boom, for example, thanks to the grips arranged at the top of each of the feet of the fixed structure, and rest it on an approximately horizontal surface.

Once the upper end of the lifting and lowering chains has been fixed to a suitable structure, the container can be raised or lowered along the designed path by operating the motor in one direction or the other.

As will be described later in this document, to achieve a partially buried installation it will be sufficient to place the aforementioned assembly inside a suitably sized pit.

According to another preferred embodiment, the system of the invention comprises an assembly as mentioned in the previous paragraphs housed in a pit. In this way, the locker container of said assembly can alternate between an upper position, where it is completely outside the pit with its lower surface essentially at ground level, and a lower position where the assembly is partially housed inside the pit.

According to a particularly preferred embodiment of the invention, the system further comprises a perimeter wall fixed to the edges of the pit to prevent the entry of water. The perimeter wall will essentially start at ground level and may have a height of approximately 50 cm to 100 cm. Naturally, the perimeter wall will be fixed outside the path of the container, that is, outside the prismatic gap of the fixed structure described above.

According to another particularly preferred embodiment of the invention, the fixed point to which the upper ends of the chains are fixed belongs to the fixed structure. Normally, it will be a point of the fixed structure located approximately at ground level.

In addition to these elements, the system of the invention will comprise a whole series of auxiliary elements, for example, electrical switchgear to control the opening/closing of the lockers, the controlled raising/lowering of the locker container, or other additional elements. More specifically, the opening/closing of the lockers will be managed through automatic closing elements controlled through wireless means managed with the help of an application installed on the user's mobile phone. This application (App) allows the user to access the locker service of the system of the invention to store his bicycle, first ordering the raising of the locker container and the opening of the door of a free locker and, after closing the locker once the bicycle has been introduced, ordering the lowering of the locker container. The App may include a whole series of additional tools for managing the system, such as payment methods to make the payment of the services according to the time of use, access to a positioning system to ensure that the user is next to the locker at the time of its use, among others.

Furthermore, a frequency converter will be used to control the frequency of the power supply to the motor in order to ensure a smooth start and stop during the container ascent/descent phases. This ensures a smooth start/stop of the motor in order to prevent breakdowns or breakages in the mechanical elements of the system.

The operation of this system is as follows. The user approaches the system and, through an application on his mobile phone, orders the locker container to rise. The frequency converter acts on the motor's power supply frequency to generate a smooth acceleration ramp until reaching a constant ascent speed, and acts again at the end of the movement to generate a speed reduction ramp. Once in the upper position, the selected locker opens automatically, and the user leaves the bicycle inside. Finally, the container descends again through a process essentially inverse to the previous one.

The installation procedure for the bicycle parking system described in the previous paragraphs essentially comprises the following steps:

1. Dig a trench with an essentially rectangular section and a depth appropriate to the size of the assembly and the distance between the upper and lower positions of the container. Reinforce the walls with concrete to withstand the stresses of the ground or insert a prefabricated manhole.

2. Place the assembly into the pit in such a way that the lifting and lowering mechanism rests on the bottom of the pit, with the container supported by said lifting and lowering mechanism. If support feet are available, the support feet of the fixed structure are adjusted to properly level the assembly.

3. Attach the perimeter wall to the edges of the pit. The perimeter wall can run the entire perimeter of the pit, or it can leave the front side open, towards which the container lockers will open.

4. Attach the upper end of each chain to the respective perimeter wall at a height approximately coinciding with ground level. The connection can be made in any way as long as the joint is strong enough to support the weight of the entire assembly and its contents.

This procedure allows a bicycle parking system such as the one described to be installed in a very short time, just a few hours. This contrasts with the prior art parking system mentioned above, where the lifting and lowering system must be assembled element by element inside the pit, which requires much more time and labour.

BRIEF DESCRIPTION OF THE DRAWINGS

Figs. 1a and 1b show perspective views of a bicycle parking system according to the invention with the assembly respectively in the upper and lower positions.

Figs. 2a and 2b show front views of a bicycle parking system according to the invention where the lifting and lowering mechanism can be seen.

Figs. 3a and 3b show profile views of a bicycle parking system according to the invention, where the lifting and lowering mechanism can be seen.

Fig. 4 shows a perspective view of the bottom of the locker container together with part of the mobile structure and the motor.

Fig. 5 shows a perspective view of a detail of the connection between a rotating shaft and the corresponding pair of drive gears driven by said shaft.

PREFERRED EMBODIMENT OF THE INVENTION

An example of a parking system (20) consisting of a partially buryable assembly (1) installed in a pit (100) is described below, referring to the attached figures.

The assembly (1) essentially comprises two elements: a container (2) and a lifting and lowering mechanism configured to raise and lower said container (2). In addition, the lifting and lowering mechanism is connected to the container (2) at the factory, which greatly simplifies the installation of the system, as will be described in greater detail below.

The container (2) of the present invention has an essentially rectangular parallelepiped shape with a rectangular horizontal section with two long sides and two short sides. The base is essentially flat, and the cover has a slight inclination to drain rainwater. The interior of the container (2) is divided into a plurality of lockers (T), specifically ten in the example shown in the figures. Each of the lockers is specifically sized and shaped to accommodate a bicycle (or scooter if necessary) inside with the greatest possible compactness.

The lifting and lowering mechanism essentially comprises a fixed structure (3), a mobile structure (4), as well as drive means designed to move the mobile structure (4) vertically in relation to the fixed structure (3).

More specifically, the fixed structure (3) is essentially formed by a frame made up of rigid beams or bars contained essentially in four vertical planes that form a rectangle of dimensions slightly larger than the container (2). In Figs. 2 and 3, some of said beams or bars are indicated with the reference symbol (3), which are arranged in such a way that the fixed structure (3) as a whole has a rectangular vertical cavity open at the top through which the container (2) can move vertically between a lower position and an upper position.

The mobile structure (4) is also made up of beams or bars that form a frame essentially contained in a horizontal plane located inside the cavity and to which the base of the container (2) is connected. In Figs. 2 and 3, some of these bars, which support the container (2), are indicated with the reference symbol (4).

Drive means arranged between the fixed structure (3) and the movable structure (4) allow the latter to be moved vertically along the vertical rectangular cavity, thus enabling the container (2) to alternate between the lower position and the upper position. These drive means comprise a motor (5) which, as shown in Figs. 2-4, is fixed to a bar of the movable structure (4) immediately below the base of the locker container (2), essentially in the centre of its rectangular plan. This motor (5) is mechanically connected through suitable gears (not shown in detail in the figures) to two rotating shafts (6a, 6b) oriented in the longitudinal direction and which essentially cover the entire distance between the opposite ends of the movable structure (4). The rotating shafts (6a, 6b) are arranged along the same longitudinal direction, as can be seen in Fig. 4. The mechanical connection between the motor (5) and the rotating shafts (6a, 6b) makes them rotate in the same direction. Each of these shafts (6a, 6b) has a respective pair of toothed wheels (81) located at their respective ends, specifically in two vertical planes (ni, rn?) perpendicular to the longitudinal direction located near the ends of the fixed structure (4) and, therefore, also near the ends of the container (2). The connection between each shaft (6a, 6b) and the corresponding pair of toothed wheels (81), which is shown in greater detail in Fig. 5, is made so that said toothed wheels (81) rotate in opposite directions. For this purpose, one of them includes an additional gear (not shown in the figures) that reverses its direction of rotation in relation to the other.

A pair of lifting and lowering chains (7) are connected at each of said ends to the aforementioned toothed wheels (81). More specifically, the path of each lifting and lowering chain (7) is as follows, always contained within the respective plane (m, m?). Its upper end is fixed to a fixed point (P) located approximately at ground level on one side of the fixed structure (4), that is, on the upper plane of the pit (100). From the fixed point (P) they descend vertically to a first idle toothed wheel (82) which reorients the chain (7) in an approximately horizontal direction towards the centre of the fixed structure (4) where the drive toothed wheel (81) is located, with which it meshes. From said drive sprocket (81), the chain (7) essentially returns in parallel again towards the lateral area of the fixed structure (4), where it meshes with a second idler wheel (83) which reorients it vertically downwards to a position close to the bottom (100F) of the pit (100), where it is fixed to a counterweight (9). The counterweight (9) is a bar also arranged in the corresponding plane (m, rn?) and spanning the entire width between the second idler wheels (83) at that end of the assembly (1), such that the lower end of the other lifting and lowering chain (7) at that end is connected to the opposite end of the same counterweight (9).

The first and second idler wheels (82, 83) are arranged in respective parts of the movable structure (4) which are slidably connected to the fixed structure (3). Thus, when the motor (5) is actuated, the shafts (6a, 6b) are caused to rotate in opposite directions. Starting from Fig. 3a, for example, if the motor is actuated in the downward direction, the right-hand drive sprocket (81) rotates clockwise, while the left-hand drive sprocket (81) rotates counterclockwise. As a consequence, the chains (7) geared to these drive sprockets (81) move upwards, i.e. the length of the upper section between said drive sprocket (81) and the fixed point (P) increases. As a result, the frame of the mobile structure (4) on which the container (2) rests descends until it reaches the situation in Fig. 3b.

In this specific example, the system (20) of the invention further comprises a perimeter wall (10) arranged around the perimeter of the pit (100) and projecting vertically upwards for a distance of approximately one metre. The fixed point (P) to which the upper end of the chain (7) is connected is rigidly attached to the base of this perimeter wall (10).

Thus, to install the system (20) described, it is sufficient to have a suitably sized pit (100). Then, using a boom, the aforementioned assembly (1) is lowered into the pit until the fixed structure (4) rests on the bottom (100F) of the pit (100). The feet (11) arranged at the bottom of said fixed structure (4) are then adjusted to ensure a stable and horizontal support. Then, once the perimeter wall (10) has been fixed along the perimeter of the pit (100), the upper end of the chains (7) is fixed to the respective points on the fixed structure (3) essentially at ground level. In the event that the chains (7) are not already pre-installed at the factory, it may be necessary to position the chains (7) along their entire length, so that they mesh properly with the aforementioned toothed wheels (81, 82, 83). Finally, it is sufficient to make the necessary electrical connections, both for power and control.

Claims (10)

1. System (20) comprising a partially buried assembly (1) for parking bicycles, comprising a container (2) provided with a plurality of bicycle lockers (T) and a lifting and lowering mechanism for moving the container (2) of lockers between an upper position and a lower position, characterized in that the lifting and lowering mechanism is fixed to a lower portion of the container (2), and because a height difference between the bottom position and the top position is less than a total height of the container (2). 2. System (20) according to claim 1, wherein the lifting and lowering mechanism comprises: a) a fixed structure (3) configured to rest on a horizontal surface, said fixed structure (3) having a vertical prismatic cavity whose horizontal section has larger dimensions than the container (2), b) a movable structure (4) rigidly attached to a lower portion of the container (2), said movable structure (4) and said container (2) being vertically slidably attached to the fixed structure (3), such that said container (2) and said movable structure (4) can ascend or descend along said prismatic cavity between the upper and lower positions; and c) actuating means connected between the fixed structure (3) and the mobile structure (4) to move said fixed structure (3), together with the container (2), between the lower position and the upper position. 3. System (20) according to claim 2, wherein the drive means comprise: c1) a drive motor (5) attached to the mobile structure (4) and whose shaft is mechanically connected to two rotating shafts (6a, 6b) oriented in a longitudinal direction, and also connected to the mobile structure (4), which extend respectively to vertical end planes (m, rn?) located at ends of the mobile structure (4), the end of each shaft (6a, 6b) being connected to a pair of drive gear wheels (81) so as to make them rotate in opposite directions; c2) two pairs of lifting and lowering chains (7) respectively contained in the end planes, nO, where each chain (7) has an upper end fixed to a fixed point (P), an intermediate point engaged in a drive toothed wheel (81), and a lower end connected to a counterweight (9) that keeps said chain (7) taut, so that the mobile structure (4) and the container (2) are hung from an upper section of the chain (7) between the fixed point (P) and the toothed wheel (81), such that, when the drive motor (5) is activated in an upward direction, the upper section of each chain (7) is simultaneously retracted, causing the level rise of the container (2) to the upper position, while, when the drive motor (5) is activated in a downward direction, the upper section of each chain (7) is simultaneously released, causing the container (2) to descend levelly to the lower position. 4. System (20) according to claim 3, further comprising a first idler sprocket (82) guiding the upper section of each chain (7) between the fixed point (P) and the drive sprocket (81), and a second idler sprocket (83) guiding a lower section of each chain (7) between the drive sprocket (81) and the connection to the counterweight (9). 5. System (20) according to any of claims 3-4, wherein the rotating shafts (6a, 6b) are located essentially centered in relation to the transverse direction to the container (2). 6. System (20) according to any of claims 3-5, comprising two beam-shaped counterweights (9), each of which is essentially contained in one of the end planes (n<1>, n^) containing each pair of chains (7), and where the lower end of a chain (7) of each pair of chains (7) is connected to one of the ends of said counterweight (9). 7. System (20) according to any of claims 2-6, wherein the fixed structure (3) comprises feet (11) to rest on the horizontal surface. 8. System (20) according to any of the preceding claims, wherein the assembly (1) is housed in a pit (100), such that it can alternate between an upper position, where the assembly (1) is completely outside the pit (100) with its lower surface essentially at ground level, and a lower position, where the assembly (1) is partially housed inside the pit (100). 9. System (20) according to claim 8, further comprising a perimeter wall (10) fixed to the edges of the pit (100) to prevent the entry of water. 10. System (20) according to claim 9, wherein the fixed point (P) to which the upper ends of the chains (7) are fixed belongs to the fixed structure (3).