EP3501995B1 - Method for controlling the parameters of a strapping system - Google Patents

Description

TECHNICAL AREA

The invention relates to a method and a device or a system for strapping objects and in particular a method for controlling the parameters of a strapping system.

STATE OF THE ART

Strapping machines have been tried and tested devices for attaching tensioned loops, mostly made of plastic tape, around objects such as packages, stacks of magazines, filled transport boxes, etc. The objects are usually transported on a conveyor into a tape guide frame. A flat strapping tape is fed to the tape guide channel in the tape guide frame by means of a tape drive. The band loop thus formed is then pulled out of the band guide channel and stretched around the object to be strapped. In this state, the formed tape loop is separated from the tape front wheel, and the two ends of the tape loop are pressed against each other and connected to each other. The loop ends are usually connected by welding. For this purpose, sealing units are used, which heat the strip material with a heating element (heating plate or heating wedge) or an ultrasonic sonotrode and press melted strip sections against one another. The WO 2008/019991 the applicant describes such a strapping machine.

The strapping station is located in the area of the tape guide frame, so that the loop formed by the tape guide frame is fastened at a specific position in a specific position around the object in the strapping position. But there are also known strapping machines without a rigid tape guide frame. To form the strap loop, the strapping strap can also be moved along the object to be strapped with lances, for example, or it can be guided through extendable strap guide channels.

The conveying device for the object usually comprises several components. For example, the strapping machine can have an infeed conveyor that transports unstrapped objects for strapping to the strapping station. Furthermore, the strapping machine can have an outfeed conveyor which transports the object away from the strapping station after strapping. Often further conveyor components are arranged in front of the infeed conveyor and / or behind the outfeed conveyor. These further conveyor components can be, for example, simple roller conveyors with a slight incline, on which the object to be strapped is transported in the direction of the incline due to its weight. However, driven roller conveyors or belt conveyors can also be used. In particular, in front of the strapping machine, an accumulation cycle conveyor is often used, which transports individual objects to the infeed conveyor of the strapping machine at predetermined times.

In practice, strapping machines are usually provided with strapping aids that support the movement of the object to be strapped or the strapping process itself. For example, at least one stop can be provided against which the object to be strapped is transported. Often two stops are used, which are in a plane running transversely to the transport direction are arranged at a distance from one another. When the object is transported against the stop by the conveyor device, its front edge is aligned parallel to the plane defined by the stops. A hold-down device can be used for strapping objects such as stacks of newspapers. This ensures that the objects lie directly on top of one another when they are strapped. In the case of compressible objects, a packing press can also be used, which presses air out of the objects to be strapped or compresses these objects against an elastic restoring force.

To control the strapping process as well as the strapping aids and the conveying device, such strapping machines have a control unit. The control unit is usually a PLC (programmable logic controller, PLC). A PLC enables programmable control on a digital basis and has been replacing hard-wired controls programmed through their connections and electronic components for several years. A PLC usually has inputs for input signals, outputs for output signals, an operating system and an interface via which programs can be loaded onto the PLC. The PLC is then programmed in the manufacturing company in such a way that a basic setting of a machine is implemented.

A service technician from the manufacturer can change the programming of the PLC in such a way that its controls can be adapted to the needs of the respective user as well as the individual requirements of the location in which the machine is set up.

It is desirable to optimize the control of such a strapping machine and the sequence of such a strapping process and, in particular, to increase the flexibility in everyday use and the quality of the strapping.

DISCLOSURE OF THE INVENTION First aspect: recording the strapping position

According to a first aspect of the development described here, a method according to claim 1 for strapping objects is created.

The present invention relates to the use of a camera. When using a camera as a recognition device, many other properties of the object can be recognized. For example, an address field or a machine-readable code can be recognized on the object. For example, newspaper parcels are often provided with a cover sheet on which the recipient's address details are printed alphanumerically and / or in machine-readable form (barcode, QR code). If strapping is placed over these address fields, the automatic reading of the address can be hindered. By evaluating the image from a camera, the position of areas that should not be covered can be determined. If nominal values for the loop position lie within these ranges, they can be changed in such a way that strapping positions lie outside the address fields or the other areas that are not to be strapped.

According to this first aspect, the present development also relates to a strapping system for strapping objects according to claim 12.

• Fig. 1 zeigt eine schematische geschnittene Vorderansicht einer Umreifungsmaschine.
• Fig. 2 - 5 zeigen Draufsichten auf eine Umreifungsmaschine und vor- und nachgelagerte Stautaktförderer.
• Fig. 6 zeigt eine schematische Draufsicht auf den Einlaufförderer und den Auslaufförderer der Umreifungsmaschine aus Fig. 1.
• Fig. 7 zeigt eine Vorderansicht eines Bandführungsrahmens der Umreifungsmaschine mit Niederhalter.
• Fig. 8 zeigt eine Vorderansicht eines Bandführungsrahmens der Umreifungsmaschine mit Anschlägen.
• Fig. 9 zeigt eine schematische Darstellung einer ersten Bildschirmanzeige für einen Umreifungseditor.
• Fig. 10 zeigt eine schematische Darstellung einer zweiten Bildschirmanzeige für einen Umreifungseditor.
• Fig. 11 -13 zeigen schematische grafische Darstellungsmöglichkeiten verschiedener Umreifungsbilder.
• Fig. 14 und 15 zeigen Bildschirmdarstellungen sogenannter Umreifungsrezepturen mit Sollwerten für alle Umreifungsparameter.
• Fig. 16 zeigt die Interaktion einer Umreifungsmaschine mit einem Datenspeicher für Umreifungsrezepturen.
• Fig. 17 zeigt eine Vorderansicht eines Verschlussaggregats einer Umreifungsmaschine.
• Fig. 18 zeigt eine dreidimensionale Rückansicht des Verschlussaggregats aus Fig. 17.
• Fig. 19 zeigt eine dreidimensionale Darstellung der Hauptwelle des Verschlussaggregats aus den Fig. 17 und 42 mit Antriebsmotor und Getriebe.
• Fig. 20 zeigt eine Seitenansicht der Hauptwelle mit Antriebsmotor und Getriebe aus Fig. 19.

Embodiments of the developments explained above are described below with reference to the accompanying drawings.

• Fig. 1 shows a schematic sectional front view of a strapping machine.
• Figures 2-5 show top views of a strapping machine and upstream and downstream accumulation cycle conveyors.
• Fig. 6 FIG. 13 shows a schematic plan view of the infeed conveyor and the outfeed conveyor of the strapping machine from FIG Fig. 1 .
• Fig. 7 shows a front view of a tape guide frame of the strapping machine with hold-down device.
• Fig. 8 shows a front view of a tape guide frame of the strapping machine with stops.
• Fig. 9 shows a schematic representation of a first screen display for a strapping editor.
• Fig. 10 Figure 12 shows a schematic representation of a second screen display for a strapping editor.
• Figures 11-13 show schematic graphic representations of various strapping images.
• Fig. 14 and 15th show screen displays of so-called strapping recipes with target values for all strapping parameters.
• Fig. 16 shows the interaction of a strapping machine with a data memory for strapping recipes.
• Fig. 17 shows a front view of a closing unit of a strapping machine.
• Fig. 18 FIG. 4 shows a three-dimensional rear view of the closure assembly from FIG Fig. 17 .
• Fig. 19 FIG. 4 shows a three-dimensional representation of the main shaft of the closure assembly from FIG Fig. 17 and 42 with drive motor and gearbox.
• Fig. 20 shows a side view of the main shaft with drive motor and gear from Fig. 19 .

The one in the Fig. 1 The strapping machine 1 shown is used for strapping objects 7 with a strapping tape 2, which is drawn off a supply roll (not shown) by a pull-in device 4 and fed to a tape magazine 5. From there, the strapping tape 2 is fed by means of a tape conveyor device 6 through a tensioning device 8 to a tape guide channel in a tape guide frame 9, so that the tape forms a loop. The tape guide frame 9 has the shape of a U with the opening at the bottom, so that the strapping tape 2 is guided from the first side of the support for the article 7 by means of the tape guide frame 9 in a U-shape around the article 7 to the other side of the support. As mentioned at the beginning, other forms of the tape guide frame and also other types of strapping are known, for example guiding the strapping around by means of grippers and lances. In the context of this development, it is essential that the strapping machine 1 creates a strap loop at a certain position. The belt is then withdrawn by the drive of the belt conveyor device 6 so that the belt loop lies tightly against the object 7. The tensioning device 8 is now activated, so that the tape loop c is pulled around the object 7 with a predetermined high tensioning force. The beginning of the loop is then connected to the end of the loop by means of a fastening unit 10. In practice, the closure unit 10 consists of a welding device, for example an ultrasonic welding device, which welds the two ends of the packaging tape loop formed to one another. Such a closure unit is, for example, in the publication EP 1 479 611 A2 described. The closure unit 10 welds the film-like plastic material from which the strapping 2 is made.

The conveyor for item 7 is shown in FIG Fig. 1 not shown. A control unit 11 for the strapping machine 1 is shown in FIG Fig. 1 shown on the right side of the strapping machine 1. The control unit 11 has a circuit board 3 with a microcontroller which controls or regulates the functions of all functional elements of the strapping machine 1. A part 12 of a plug connection, which in the present case is designed as a socket part 12 of the plug connection, is arranged on the control unit 11.

The control unit 11 also controls the drives for strapping aids, in particular additional units of the strapping machine 1. In Fig. 1 a hold-down device 22 can be seen as the first additional unit, which presses on the object 7 to be strapped from above. Furthermore, a left stop 25 and a right stop 26 can be seen as additional units, which align the object 7 to be strapped before the strapping process. The two stops are attached to the tape guide frame 9 and driven in opposite synchronism, that is, they are at the same distance from the center of the strapping machine 1 at all times. The function of the stops 25, 26 is also described in more detail below.

The Figures 2-5 show schematic top views of a strapping machine 1 with upstream and downstream accumulation cycle conveyors 15, 16 and with the packages 7, 7 'to be strapped. The strapping machine 1 itself has two conveying devices. An infeed conveyor 13, which is in the Figures 2-5 to the left of the tape guide frame 9, and an outfeed conveyor 14, which is in the Figures 2-5 to the right of the tape guide frame 9. The infeed conveyor 13 and the outfeed conveyor 14 each consist of a pair of synchronously driven conveyor belts. The upstream accumulation cycle conveyor 15 and the downstream accumulation cycle conveyor 16 can be any desired conveying means, for example belt conveyors or roller conveyors.

The conveying direction for the object 7 to be strapped, usually a package, is shown as an arrow above the accumulation cycle conveyor 15 on the input side. Of course, the conveying direction of all conveying devices can also be reversed.

All representations show a first position detection device 17 near the end of the infeed conveyor 13 furthest away from the tape guide frame 9. The tape guide frame 9 defines the strapping position. A strap loop is formed by the strapping machine in the center plane of the strap guide frame 9. The embodiment of the strapping machine in Fig. 4 and 5 has a further position detection device 18 close to the tape guide frame 9. In this embodiment, a third position detection device 19 is arranged in the area of the end of the outfeed conveyor 14 remote from the tape guide frame 9. The position detection devices 17, 18, 19 usually consist of light barriers. Each light barrier 17, 18, 19 has a light source and a light sensor. The light sensor receives the light from the light source a short distance above the infeed conveyor 13 or the outfeed conveyor 14. This ensures that the position detection means 17-19 detect both flat and tall objects.

The position detection means 17 located near the entry-side accumulation cycle conveyor 15 transmits a signal to the control unit 11 of the strapping machine 1 as soon as an object 7 is transported from the entry-side accumulation cycle conveyor 15 onto the infeed conveyor 13. The infeed conveyor 15 is driven by a drive motor 57 ( Fig. 6 ) driven, which has a rotary encoder. When the drive shaft of the drive motor 57 rotates, the rotary encoder generates signals at fixed angular intervals, which signals are sent to the control unit 11. The signals are schematically in Fig. 6 shown as a square wave. It can be seen that two signals with the same frequency but a phase offset are emitted by the drive motor 57 of the infeed conveyor 13. Due to the phase shift, the different directions of rotation can be identified by the control unit. As explained above, the distance between two signals of the drive motor 57 of a conveying path of the infeed conveyor 13 can correspond to the order of magnitude of 0.3 to 0.6 mm. The discharge conveyor 14 is driven by a corresponding drive motor 58. This drive motor 58 also emits signals to the control unit 11 which correspond to the conveying path of an object on the outfeed conveyor 14 and allow the conveying direction to be recognized.

Because the conveying direction and conveying path of the infeed conveyor 13 and the outfeed conveyor 15 are recorded, it is possible at any time from the first detection of the position of the object when passing the input-side light barrier 17 to find out the position of an object on the conveyor devices 13, 14 of the strapping machine 1 7, 7 'to be determined. This position determination can be made more precise by the second position detection means 18 and the third position detection means 19. Depending on the application, the upstream accumulation cycle conveyor 15 can have a different conveying speed than the infeed conveyor 13 of the strapping machine. This can cause a slip between the conveyor belt of the infeed conveyor 13 and the object 7, 7 'to be strapped. If the upstream accumulation cycle conveyor 15 runs faster, the object 7, 7 'to be strapped is moved ahead faster than the conveyor belts of the infeed conveyor 13. If the accumulation cycle conveyor 15 runs slower, the object 7 moves more slowly than the infeed conveyor 13 until its weight is essentially only is carried by the conveyor belts of the infeed conveyor 13. If a second position detection means 18 is present near the tape guide frame 9, this can detect the actual position of the front edge of the object 7, 7 ′ to be strapped near the strapping plane of the tape guide frame 9. In this way, any slippage that may be present between the object 7, 7 ′ to be strapped and the infeed conveyor 13 can be compensated for. A position detection means 19 can also be provided at the opposite end of the strapping machine 1, ie at the edge of the outfeed conveyor 14 remote from the tape guide frame 9 (see FIG Fig. 4 and 5 ). This then enables the strapping machine 1 to be operated in both directions. In addition, the position detection means 19 detects the rear edge of the object 7 to be strapped in the conveying direction shown during removal and indicates when the strapping machine 1 is completely free for another object to be strapped.

The position of the object 7, 7 'to be strapped is controlled using the position detection means 17, 18, 19 and the detection device for the conveying direction and conveying path of the infeed conveyor 13. After the front edge of the object 7, 7' to be strapped, its position is continuously known because it can be calculated from the conveying route and conveying direction of the conveying device, ie the infeed conveyor 13. This position value can be corrected again near the tape guide frame 9 if the second position detection means 18 is provided here. The position can be controlled with an accuracy of less than 1 mm on the basis of the incremental signals that the detection device emits to detect the conveying direction and conveying path. During the further transport of the object 7, 7 'to be strapped, the rear edge of the object 7, 7' to be strapped is also detected on the position detection means 17. Since the conveying path is known, the length of the object 7, 7 'to be strapped can be derived from this. This also makes it possible to avoid disturbances due to accumulations. With earlier strapping devices, the strapping positions were fixed by means of fixed time cycles of the strapping machine. If, for any reason, the item being strapped was too short, a tape loop was still formed. Such empty strapping can lead to malfunctions in the strapping machine. With the present development, such disturbances can be avoided. If it is determined that a strapping position would create a loop outside the contours of the object 7, 7 'to be strapped, the strapping at this position can either be avoided or the object 7, 7' to be strapped can be shifted in this way by the control unit 11 of the strapping machine 1 that the position of the strapping is safely within the contours of the object 7, 7 'to be strapped. Such a shift can also take place if it is determined that a loop is to be created with too little distance from the front edge or from the rear edge of the object to be strapped.

By determining the length of the object to be strapped, it is also possible to precisely approach the center of the object 7, 7 'to be strapped. In the Figs. 2 and 3 a first object 7 to be strapped is shown, the length of which is already recorded when the first strapping is applied. The one to be strapped Item 7 'in Fig. 5 is longer. Its total length can only be recorded when its center has already been transported past the strapping plane of the tape guide frame 9. In this case, to determine the precise length of the object 7 'to be strapped, it can be moved into a position in which its length is known by the signal from the position detection means (light barrier) 17 because the rear edge of the object 7' to be strapped is on the position detection means 17 runs past. The object 7 'to be strapped can then be transported back in order to produce a central strapping exactly in its center.

If the transport of the object 7 'to be strapped is too complex in two directions, the machine control can also simply enable further transport and omit the central strapping. As described elsewhere, however, the length of the object 7 'can also be determined in advance and transmitted to the control unit. In this case, central strapping is possible without the rear edge of the object having passed through the light barrier 17.

The strapping patterns that can be formed with this strapping machine can have any structure. Exemplary structures of the strapping patterns are described below.

In the Fig. 5 a detection device 20 is also shown schematically on the tape guide frame 9 approximately in the middle above the strapping zone. The recognition device 20 can be a scanner for printed codes (barcode or QR code). It can also be a camera which records an image of the strapping zone below the tape guide frame 9. The camera can also identify and read codes printed on the recorded image. Furthermore, a reading antenna for RFID transponders can be used as the detection device 20, which can be attached to the objects 7, 7 'to be strapped. The detection device 20 can of course also have several components (camera and RFID reading antenna). The recognition device 20 makes it possible to recognize properties of the object to be strapped, on the basis of which the strapping position can be varied.

For example, a camera as a detection device 20 can detect dimensions or other properties of the object to be strapped, which have an influence on the loop position. Using certain identifiers of the object, such as the color of the packaging or a machine-readable code printed on the object, further properties of the object can be identified. For example, the strength of the object or the weight can be coded so that the correct strap tension or the required number of straps can be determined for the object with the corresponding properties. Particularly when a camera is used as the detection device 20, areas on the object can also be identified in which no tape loop should be arranged.

In Fig. 5 it can be seen that the object 7 to be strapped has an address field 21. In the address field 21, for example, a barcode with information about the object 7 to be strapped or with address information can be arranged. The address information can also be printed on the address field 21 as readable alphanumeric information. The dash-dotted lines in Fig. 5 show the area captured by the camera as the recognition device 20. If an address field 21 is identified by the camera 20, the control unit 11 of the strapping machine 1 can control the conveying devices 13, 14 of the strapping machine 1 in such a way that the tape loops are not generated on the address field 21.

The Fig. 7 shows the front view of the tape guide frame 9 and the hold-down device 22 arranged on the tape guide frame 9. The hold-down device 22 is used, for example, when strapping objects 7 such as stacks of newspapers. Before the tape loop is applied, the hold-down device 22 is pressed from above onto the object 7 to be strapped, so that individual elements of the object 7 rest firmly against one another. In the case of larger objects 7, in particular packed pallets, instead of a hold-down device 22, a packing press can also press on the object 7 from above in order to compress it.

Fig. 7 also shows schematically the drive motor 23 for the hold-down device 22. This drive motor 23 is also equipped with a rotary encoder which emits signals at regular intervals when the motor shaft of the drive motor 23 rotates. The hold-down device 22 forms a first strapping aid of the strapping machine 1. Using the signals from the drive motor 23 for the hold-down device 22, its movement data are continuously recorded and transmitted to the control unit 11 of the strapping machine. The control unit 11 of the strapping machine 1 controls the hold-down device 22 on the basis of this movement data to numerically predetermined setpoint values.

The movement path of the hold-down device 22 has at least one stop position. Two positions of the hold-down are in Fig. 7 shown. The upper position P ₀ is the upper stop position of the hold-down device 22. At the beginning of the operation of the strapping machine 1, the hold-down device 22 is moved to the topmost position P ₀ . Subsequently, during the operation of the strapping machine, the current position of the hold-down device 22 is known in each case on the basis of the movement data, namely the signals of the drive motor 23. In this case, the position P ₀ is the reference position, in relation to which the current position of the hold-down device 22 is determined by means of the movement data.

As described above, the strapping machine 1 can be coupled to detection devices that detect at least one property of the objects transported by means of the conveyor device; the detection device can be a camera that allows the height of the object or the length of the object to be determined via image analysis. A height measuring device can be provided which works with optical or acoustic signals. Such a height measuring device is known in various embodiments. In particular, the height of the object 7 to be strapped is significant for the operation of the strapping machine 1 with hold-down device 22.

In the prior art, the hold-down device 22 assumed the uppermost stop position P ₀ after each strapping operation. By recognizing the height of the object 7 to be strapped, it is possible to dispense with moving the hold-down device 22 in each case to the uppermost position P ₀ . The hold-down device 22 is only to be arranged a certain distance above the object 7 to be strapped. This safety distance 24 is in Fig. 7 Drawn in hatched lines and provided with the reference number 24. In the position P ₁ , the hold-down device 22 is located by the safety distance 24 above the object 7 to be strapped. To feed the object 7, it is sufficient to raise the hold-down device 22 to this position P ₁ . Since it is not necessary to wait for the further transport of the object to be strapped until the hold-down device 22 has been moved to the position P ₀ , the strapping process and in particular the transport process for the object 7 to be strapped can be considerably accelerated. In the active position (not shown), the hold-down device 22 rests on the upper side of the object to be strapped and exerts a compressive force on it.

The Fig. 8 shows the tape guide frame 9 to the other, in FIG Fig. 1 Strapping aids shown, namely two synchronously driven stops 25, 26. The stops 25, 26 are driven by a drive motor 28 and are coupled in such a way that they are the same distance from the center of the at all times Have tape guide frame 9. At the maximum distance D ₀ , the two stops 25, 26 rest against outer movement stops. The drive motor 28 in turn emits rotational angle signals when turning.

At the beginning of the operation of the strapping machine 1, the stops 25, 26 are moved to a maximum distance D ₀ from one another. This position is the reference position of these strapping tools. Alternatively, the abutment against a central stop can be used as a reference position against which the stops 25, 26 rest at a minimal distance. Based on the reference position, the current position of the stops 25, 26 can be determined at any time by the control unit 11 of the strapping machine 1 through the rotation angle signals of the drive motor 28.

When controlling the stops 25, 26, the control unit 11 again takes into account at least one property of the object to be strapped, in particular its width. This is detected with one of the detection devices already described above. The stops 25, 26 are spaced apart from one another such that they are located within the contour of the object 7 to be strapped as close as possible to its outer edges. This is in Fig. 8 the distance D ₁ between the two stops 25, 26. The conveyor device of the strapping machine 1, in particular the infeed conveyor 13, conveys the object 7 to be strapped in relation to FIG Fig. 8 towards the viewer. The object 7 to be strapped consequently hits with its in Fig. 8 visible front against the two stops 25, 26. By means of the control unit 11, the stops 25, 26 are set to the greatest possible distance from the center of the strapping machine 1, so that they still lie securely within the contours of the object 7 to be strapped. This ensures that an object 7 to be strapped, which is moved by the infeed conveyor against the stops 25, 26, aligns itself with the plane of the stops 25, 26 if it is slightly inclined. Even if the object 7 to be strapped consists of individual objects, magazines or the like, the entire front surface of the object 7 to be strapped is aligned with the plane which is formed by the two stops 25, 26.

The stops 25, 26 are moved apart when the object 7 to be strapped is transported further. So far, the stops 25, 26 have been moved apart _{in their starting position with the distance D 0.} In the present development, it is sufficient to move the stops 25, 26 into a position in which the object 7 to be strapped can easily pass through the stops 25, 26. In Fig. 8 this position is reached when the stops 25, 26 have a slightly smaller distance than D _{0 from} one another. This distance can be redefined for each package width (width of the object 7 to be strapped). In this way it is ensured on the one hand that the object 7 to be strapped is safely moved through between the stops 25, on the other hand it is avoided that the stops 25, 26 have to cover unnecessary travels, which takes unnecessary time.

In the case of the strapping aids, ie the stops 25, 26 and the hold-down device 22, the control unit 11 can monitor the movement data and compare it with setpoint values. If the acceleration or speed of this strapping aid deviates impermissibly from a predetermined target value at any point in time, the movement of the strapping aid can be stopped or the strapping aid 22, 25, 26 can be driven a certain distance in the opposite direction. The deviation from the movement data can indicate that the strapping aid encounters resistance and a further drive in the predetermined direction could result in damage to either the object or the strapping aid. When the strapping aid is stopped or withdrawn, a warning signal can be sent to a service technician at the same time.

The Fig. 9 shows a first screen display for programming a strapping machine according to the present development. The screen itself can either be arranged directly on the strapping machine 1. Alternatively, it can be connected to a control computer which is connected to the strapping machine 1 via a local network or a wide area network (WAN) such as the Internet. Several icons can be seen on the screen that designate different strapping recipes. The icon 101 on the left indicates the pass in which no strapping takes place. The icons 102 to 107 designate six different strapping recipes. The icon 108 activates the programming screens on which the strapping by the strapping machine 1 can be defined.

Fig. 10 shows a programming screen on which the strapping positions can be defined numerically. A screen display 109 with a package on a conveyor belt can be seen in the upper center. This screen display shows the overall picture with all strapping. Below that, three strapping positions are defined in three representations 110-112 arranged one below the other. The strapping position shown above is determined by a distance of 100 mm from the front edge of the package. The middle strapping position is defined by a distance from the center of the package. No value is given here, so this distance is zero. The strapping position shown below is defined by a distance from the rear edge of the package, here again 100 mm. Any number of strapping positions can be added. If necessary, the positions must be divided over several screen displays. The positions can be entered numerically, for example using a keyboard.

The illustrations to the right of the strapping positions relate to the strap tension. This is shown here graphically with a symbol for the standard belt tension. However, it can also be specified numerically as a percentage of a predefined standard belt tension.

Possible resulting strapping patterns are in the Figures 11 to 13 shown. Fig. 11 shows a first individual strapping at a distance from the front edge, a second individual strapping in the middle and a third individual strapping at a distance from the rear edge. This variant corresponds to the one shown on the screen in Fig. 10 defined strapping. The Fig. 12 shows a multiple strapping, here a quadruple strapping, with a predetermined distance from the front edge and a corresponding multiple strapping with a predetermined distance from the rear edge. A single strapping is provided here as central strapping. The Fig. 13 shows a front strapping a predetermined distance from the front edge and a rear strapping a predetermined distance from the rear edge. In between there is a plurality of equidistant straps. In this way, depending on the length of the package to be strapped, multiple strapping can be produced with uniform distances between two individual straps. The distances between the equidistant strapping can be entered on the input screen or automatically calculated by the control unit 11 with an optimal value on the basis of the measured package length.

The representations of the Figures 11 to 13 can be used to display the object and the strapping to be applied on a screen of a strapping editor. Instead of entering the distances numerically, the distance is defined here simply by marking one of the strapping representations with a mouse and by clicking and moving it (drag & drop) on the object to be strapped.

The strapping positions defined on the screen are converted into numerical data to determine the loop position on the object and set by the control unit of the strapping machine 1.

The control unit 11 controls the conveying device 13, 14 for the object 7 to be strapped in such a way that in each case a loop is generated at a position predetermined by means of the strapping editor on the screen. Data records programmed in this way with setpoint values for the strapping parameters are preferably stored in a data memory which is connected to the control unit 11. This is schematically shown in Fig. 16 shown. The data memory 29 can be a data memory integrated in the control unit 11. Known writable data memories such as hard disks, SSD memories are suitable for integration in the control unit 11 of the strapping machine 1. However, ROM data memories such as CDs can also be provided with the data records of the setpoint values. For example, when the manufacturer optimizes the machine control, a CD or DVD can be used to change the stored data. In this case, the strapping machine 1 or a computer networked with it is provided with a reading unit for such data carriers.

The strapping machine 1 can also be connected to the Internet or a closed computer network. In this case, the manufacturer of the strapping machine 1 can overwrite a writable data memory of the control unit 11 with updated data. Alternatively, the control unit 11 of the strapping machine 1 can access a data memory 29 during operation via the Internet or another data network, on which the strapping parameters specified by the manufacturer or user of the strapping machine 1 are stored. Any combination of internal and external data storage is possible. For each object to be strapped, a data record with setpoint values for the strapping parameters can be selected, which are set by the control unit on the strapping machine 1. The data record not only includes the strapping positions and the strap tensions, it can also contain the position of the hold-down device 22, the stops 25, 26 of a packing press or other additional units or strapping aids, which are controlled by the control unit 11 of the strapping machine 1.

The data record can also be fed to the strapping machine 1 in the form of package accompanying data. These package-accompanying data can be stored, for example, in an RFID transponder which is attached to the object 7 to be strapped. Alternatively, they can be entered in a printed machine-readable code. This code can be read out by a reading device of the strapping machine 1 (e.g. camera, code scanner, receiving antenna for reading out RFID transponders).

Simple identifiers can also be attached to the package (e.g. via RFID transponders or printed codes), which are each assigned to the data records. After the identifier has been read out, these data records are read out from a local data memory of the strapping machine 1 or from a remote data memory 29 via a network.

Alternatively, the data set with the strapping parameters can be selected by recognizing at least one property of the object. Strapping machines are often located in logistics centers in which only a limited number of objects are strapped. A certain strapping program can be assigned to each item. The objects are then either identified using specific identifiers that are read out, or simply using their height, width, length, weight or contour. The contour detection can in turn be ensured with a camera 20 which is attached to the strapping machine 1.

However, the light barriers or light barrier strips described above can also be used to detect at least one property of the object to be strapped.

The Fig. 14 and 15th show an example of a structure of the data records for nominal values of the strapping process. First of all, in Fig. 14 the strapping pattern listed, which can include a variety of strapping positions. Second, the belt tension is in Fig. 14 listed. This can either correspond to the standard strap tension of the strapping machine or be selected depending on the height. Any other selection method for belt tension, including manual entry, is possible.

For the conveying devices, that is to say the infeed conveyor 13 and outfeed conveyor 14 of the strapping machine 1, setpoint values can also be specified in the "Transport" section. These can include the maximum transport speed, the start and stop ramp, i.e. the acceleration during the acceleration process and the deceleration during the braking process, a strapping trigger over a distance of the conveyed distance to the interval strapping and other values. The "Machine options" section contains the setpoints for additional units and strapping aids. The setpoints for the hold-down device and the stops are in Fig. 15 specified more precisely.

The Fig. 17 FIG. 11 shows a front view and FIG Fig. 18 a perspective rear view of a closure unit of a strapping machine according to the development described here. The details are particularly in the perspective rear view of the Fig. 18 to recognize. A belt drive 30 and a tensioning drive 31 can be seen here. The belt drive 30 is continuously coupled to a drive roller 32 which is coupled to the strapping band 2 (not shown in FIGS. 41-44). The tensioning drive 31, on the other hand, is pivotably attached to a rocker 34 so that, depending on the operating state of the machine, it can be pressed against a second tensioning roller 35 with the tensioning roller 33 driven by it.

Furthermore, a welding device 36 is provided which welds the ends of a band loop formed. To the right and left of the welding device 36, clamps are provided, which are formed by clamping punches 37, 38 which are pressed against an abutment plate and clamp the beginning and the end of a band loop formed. The welding device 36 welds the band areas lying between the clamps 37, 38 to one another.

At least the two clamping punches 37, 38 and the welding device 36, but preferably all of the movable components of the closure unit 39, are driven by a main shaft 40, also called a vertical shaft. For this purpose, several cam disks 41 to 46 are arranged on the main shaft 40. The cam 41 controls the first Klcmmstcmpcl 37. The cam 42 controls the second clamping ram 38. The cam 43 controls the welding device 36. The cam 44 controls an upper slide 47, which is moved to an abutment for the clamping rams 37 and 38 during welding and to form the welder 36. In the second sliding position, it clears a gap in the strapping machine so that the band loop that is formed can emerge from the closure assembly 39.

Another cam 45 actuates the rocker 34 with the tensioning drive 31 and engages or disengages it. A cam 46 opens and closes the tape guide frame. While the tape is being shot into the tape guide frame, the latter is closed. To pull out the loop formed in the tape guide frame, the latter is opened.

The main shaft 40 is controlled in precise angular positions according to the present development. This is done by means of signals from the drive motor 48 for the main shaft 40. This is shown in FIG Fig. 19 to recognize in Fig. 18 but not shown for the sake of clarity. As already mentioned above, the drive motor 48 a rotary encoder which emits at least one signal pulse per degree of rotation angle of the main shaft 41. Two signal pulses are preferably emitted per degree of rotation angle. As in particular in the Figures 19 and 20 As can be seen, the drive motor 48 is coupled to the main shaft 40 via a reduction gear 49. Several revolutions of the drive motor 48 are consequently required in order to cause a single revolution of the main shaft 40.

Especially in the Fig. 20 it can be seen that a cam disk 50 is attached to the free end of the motor shaft on the other side of the reduction gear 49, which works together with a proximity switch 51. Along the circumference of the cam disk 50, five positions are marked with the numbers 0, 1, 2, 3, 4, which are each assigned to a cam 52-55 on the circumference of the cam disk 50. The proximity switch 51 outputs a signal to the control unit 11 of the strapping machine 1 when the cam disk 50 is in a position in which one of the cams 52-55 is located near the proximity switch 51. The five positions marked on the cam disk 50 still correspond to the position control for the main shaft according to the prior art. Each of the five positions to which a cam 52-55 is assigned corresponds to a setpoint value for the angular position with the main shaft 40. The different angular positions into which the main shaft 40 can be rotated during each strapping cycle are described above. The cam disks 41 - 46 move each component controlled by the main shaft 40 in the angular positions marked by one of the cams 52 - 55 in each case into a position which is assigned to the corresponding operating state of the strapping machine 1. For this reason, the marked angular position should be controlled as precisely as possible.

The control unit 11 of the strapping machine 1 also receives the signals from the drive motor 48 for the main shaft 40 via a signal line 56, which signals each correspond to a specific angle of rotation of the main shaft 40. Consequently, the cams 52-55 on the circumference of the cam disk 50 are no longer required for recognizing the actual value of the angle of rotation of the main shaft 40. One of the cams 52-55 is sufficient for the control unit 11 of the strapping machine 1 to be able to detect the signal from this cam as a reference for the absolute angular position of the main shaft 40. The other cams on the cam disk 50 can be removed.

Due to the reduction of the reduction gear 49, the drive motor 48 sends over 700 signal pulses to the control unit 11 on the strapping machine 1 with each revolution of the main shaft 40, which represent a rotation of the main shaft 40 by a certain angular segment of the strapping machine 1 can resolve the rotational position of the Hauptwcllc 40 with an accuracy of 0.5 °.

Of course, the in Fig. 20 The five cams 52 - 55 shown may be arranged on the circumference of the cam disk 50. For the reliable operation of the strapping machine 1 with a rotation angle detection of the main shaft 40, a single cam 52-55 or a similar marking is sufficient, which is clearly assigned to a specific rotational position of the main shaft 40 and is automatically recognizable. The control unit 11 of the strapping machine 1 can consequently set the optimum angle of rotation of the main shaft 40 in each case. If, on the basis of the signals from the drive motor 48, deviations in the actually reached rotational position of the main shaft 40 are detected, these can be corrected immediately during the next drive process, so that, for example, the braking of the main shaft 40 can be initiated earlier or later by deactivating the drive motor 48 so that the next approached angular position of the main shaft 40 corresponds exactly to the target value. The actual value achieved in the previous strapping cycle can also be taken into account from a first angular position, for example for the welding process, to the next, identical angular position in the subsequent strapping cycle in order to control the Drive motor 48 to vary by the control unit 11. If, for example, the actual value is greater than the setpoint in the locking position, braking can be initiated earlier the next time this position is approached. If the setpoint is lower, braking can be initiated later.

List of reference symbols

1

Strapping machine

2

tape

3

circuit board

4th

Pull-in device

5

Tape magazine

6th

Belt conveyor

7.7 '

object

8th

Jig

9

Tape guide frame

10

Locking unit

11

Control unit

12th

Socket part

13th

Infeed conveyor, first conveyor device

14th

Outfeed conveyor, second conveyor device

15th

Accumulation cycle conveyor on the entrance side

16

accumulation cycle conveyor on the output side

17th

Position detection device, light barrier

18th

Position detection device, light barrier

19th

Position detection device, light barrier

20th

Camera, detection device

21

Address field

22nd

Hold-down devices, strapping tools

23

Drive motor for the hold-down device

24

Safety distance

25th

left stop, strapping aid

26th

right stop, strapping aid

28

Drive motor for the stops

29

Data storage

30th

Belt drive

31

Tension drive

32

Drive roller

33

Tension pulley

34

Seesaw

35

Tension pulley

36

Welding device

37

Clamp, clamp stamp

38

Clamp, clamp stamp

39

Locking unit

40

Main shaft, bevel shaft

41

Cam for the first clamping punch

42

Cam for second clamping stamp

43

Cam for welding device

44

Cam for top slide

45

Cam for clamping drive

46

Cam for tape guide frame

47

Top slide

48

Drive motor for the main shaft

49

Reduction gear

50

Cam disc

51

proximity switch

52-55

cam

56

Signal line

57

Drive motor for infeed conveyor

58

Drive motor for outfeed conveyor

101

Pass icon

102

Strapping recipe

103

Strapping recipe

104

Strapping recipe

105

Strapping recipe

106

Strapping recipe

107

Strapping recipe

108

Activation icon

109

Screen display

110

Representation of the strapping position

111

Representation of the strapping position

112

Representation of the strapping position

Claims (14)

1. Method for strapping objects, the method comprising the following steps:

   • conveying an object (7, 7') to a strapping station using a conveying device (13, 14),

   • forming at least one loop of strapping tape (2) around the object (7, 7') using a strapping device,

   • connecting the ends of the loop with one another,

   • controlling strapping parameters which comprise at least the strapping position using a control unit (11),

   characterized by the following steps:

   • detecting the optical properties of the object (7, 7') using a camera (20);

   • evaluating of the image of the camera (20) for determining areas which are not to be covered by strapping;

   • controlling the strapping position so that the strapping position is outside the areas not to be strapped.
2. Method according to claim 1, characterized in that the areas not to be strapped include address fields.
3. Method according to claim 2, characterized in that the package length is determined by analysing the image recorded by the camera.
4. Method according to claim 3, characterized in that reference values for the loop position are calculated depending on the package length.
5. Method according to claim 3, characterized in that the reference values for the loop position are retrieved from a data memory in which different loop positions for different package lengths are stored.
6. Method according to any one of the preceding claims, characterized in that a machine-readable code on the article (7,7') is identified and read in the image recorded by the camera (20).
7. Method according to claim 6, characterized in that in the machine-readable code at least one of the following information is encoded:

   • an identifier for the object (7, 7'), for which properties of the object or directly reference values for the loop position are stored in a data memory, the reference values for the loop position being determined by reading from the data memory or by evaluating the property or properties and assigning or calculating corresponding reference values;

   • reference values for the loop positions.
8. Method according to any one of the preceding claims, characterized by the following steps:

   • detecting at least one property of the object (7, 7') by the camera (20) and transmitting the data specifying the property of the object (7, 7') to the control unit (11);

   • selecting, by means of the control unit (11), a data set with reference values for the strapping parameters on the basis of the data specifying the at least one property of the object (7, 7').
9. Method according to claim 4, characterized in that at least one of the following properties is identified:

   • height of the object (7, 7');

   • width of the object (7, 7');

   • length of the object (7, 7');

   • strength of the object (7, 7');

   • contour of the object (7, 7');

   • colour of the object (7, 7').
10. Method according to one of claims 8 and 9, characterized in that the data set comprises reference values for at least one of the following strapping parameters:

    • distance of the strapping position from the front edge of the object (7, 7');

    • distance of the strapping position from the rear edge of the object (7, 7');

    • number of strappings;

    • tape tension of the strapping tape (2);

    • position of a stop during the strapping operation;

    • position of the stop during the conveyance of the object (7, 7');

    • position of a hold-down device or a packing press during the conveyance of the object (7, 7');

    • pressing force of the hold-down device or the packing press during the strapping operation.
11. Strapping system for strapping objects according to the method of one of the preceding claims, the system comprising the following features:

    • at least one conveying device (13, 14) for conveying an object (7, 7') to a strapping station,

    • at least one strapping device for forming a loop of strapping tape (2) around the object (7, 7'),

    • at least one connecting device for connecting the ends of the loop with one another,

    • a control unit (11) for controlling several strapping parameters, including the strapping position of the strapping tape (2) arranged around the object (7, 7'),

    • an identification device (20) for identifying at least one property of the object (7, 7') and for transmitting the data specifying the property of the object (7, 7') to the control unit (11), wherein the identification device is a camera (20) for detecting the optical properties of the object (7, 7').
12. Strapping system according to claim 11, characterized in that at least one property of the object (7, 7') is identifyable by means of the camera and that means for transmitting the data specifying the property the object (7, 7') to the control unit (11) are provided, wherein the data are used for the selection of a data set comprising reference values for the strapping parameters based on the at least one property of the object (7, 7').
13. Strapping system according to claim 12, characterized in that the camera (20) is adapted to identify at least one of the following properties:

    • height of the object (7, 7');

    • width of the object (7, 7');

    • length of the object (7, 7');

    • strength of the object (7, 7');

    • contour of the object (7, 7');

    • colour of the object (7, 7').
14. Strapping system according to one of claims 11 to 13, characterized in that the control unit (11) is adapted to control at least one of the following strapping parameters:

    • distance of the strapping position from the front edge of the object (7, 7');

    • distance of the strapping position from the rear edge of the object (7, 7');

    • number of strappings;

    • tape tension of the strapping tape (2);

    • deceleration and acceleration of the conveying device (13, 14);

    • position of a stop during the strapping operation;

    • position of the stop during the conveyance of the object (7, 7');

    • position of a hold-down device or a packing press during the conveyance of the object (7, 7');

    • pressing force of the hold-down device or the packing press during the strapping operation.

Images