Control device and method for a strapping machine

Abstract

Method for strapping objects, comprising the following steps: • Transporting an object (7, 7') by means of at least one conveyor device (13, 14) to a strapping station, • Forming at least one loop of a strapping band (2) around the object (7, 7') by means of a strapping device, • Connecting the ends of the loop together, • Detecting the position of the object (7, 7') by at least one position detecting means (17, 18, 19), • a detection device detects the conveying direction and conveying distance of the conveying device (13,14), • the signals of the detection device and the position detection means (17, 18, 19) are transmitted to a control unit (11), • the control unit (11) controls the conveyor device (13, 14) on the basis of the transmitted signals in such a way that the object (7, 7') is transported into at least one strapping position in which the loop of strapping band (2) is formed on the object (7, 7') at a predetermined loop position, • at least one property of the object (7, 7') is recognized by a recognition device (20), • Data specifying the property of the object (7, 7') are forwarded to the control unit (11) and • the control unit (11) determines at least one target value for the loop position from the data specifying the property of the object (7, 7'), characterized by the following steps: • Storing data sets with target values ​​for the strapping parameters in a data memory (29) which is connected to the control unit (11); • Selection of a data set with target values ​​for the strapping parameters by the control unit (11) for each strapping process, wherein the data set is selected by the control unit (11) on the basis of the data specifying the at least one property of the object (7, 7').

Description

TECHNICAL FIELD

[0001] The invention relates to a method and a device or system for strapping objects. It particularly relates to a strapping method according to the preamble of claim 1. STATE OF THE ART

[0002] Strapping machines have been proven for decades as devices for applying tensioned loops, usually made of plastic strapping, around objects such as packages, stacks of magazines, filled transport crates, etc. The objects are usually transported on a conveyor into a strap guide frame. A flat strapping band is fed into the strap guide channel in the strap guide frame by a belt drive. The thus formed strap loop is then pulled out of the strap guide channel and tensioned around the object to be strapped. In this state, the formed strap loop is severed from the strap feed wheel, and the two ends of the strap loop are pressed against each other and joined. The loop ends are usually joined by welding.For this purpose, sealing units are used that heat the strap material using a heating element (heating plate or heating wedge) or an ultrasonic sonotrode and press molten strap sections against each other. WO 2008 / 019991, owned by the applicant, describes such a strapping machine.

[0003] The strapping station is located in the area of ​​the strap guide frame, so that the loop formed by the strap guide frame is secured at a specific position around the object in the strapping position. However, strapping machines without a rigid strap guide frame are also known. To form the strap loop, the strapping can be moved along the object to be strapped, for example, using lances or guided through extendable strap guide channels.

[0004] The conveyor device for the object usually comprises several components. For example, the strapping machine can have an infeed conveyor that transports unstrapped objects to the strapping station for strapping. The strapping machine can also have an outfeed conveyor that transports the object away from the strapping station after strapping. Additional conveyor components are often arranged upstream of the infeed conveyor and / or downstream of the outfeed conveyor. These additional conveyor components can, for example, be 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, a buffer conveyor is often used in front of the strapping machine, which transports individual items to the infeed conveyor of the strapping machine at predetermined times.

[0005] In practice, strapping machines are usually equipped 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. Two stops are often used, which are arranged at a distance from each other in a plane running transversely to the transport direction. When the object is transported by the conveyor device against the stop, its front edge is aligned parallel to the plane defined by the stops. For strapping objects such as stacks of newspapers, a hold-down device can be used. This ensures that the objects lie directly on top of one another during strapping.For 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.

[0006] Such strapping machines are equipped with a control unit to control the strapping process, the strapping aids, and the conveyor system. The control unit is usually a PLC (Programmable Logic Controller). A PLC enables programmable control on a digital basis and, for several years now, has replaced hard-wired controllers programmed through their connections and electronic components. A PLC typically has inputs for input signals, outputs for output signals, an operating system, and an interface via which programs can be loaded onto the PLC. In the manufacturing company, the PLC is then programmed to implement a basic machine setting.

[0007] A service technician from the manufacturer can modify the PLC programming to adapt its controls to the needs of the respective user and the individual requirements of the location where the machine is installed.

[0008] Document DE 2 325 087 B1 discloses a time-controlled positioning method in which the position of the object is determined by a pre-programmed actuation time of the conveyor drive. Document DE 693 26 086 T2 discloses a strapping device with an encoder that counts a predetermined number of revolutions of a conveyor belt shaft required to move a package into the strapping position. Here, too, a change in the strapping position can only be achieved through complex reprogramming of the PLC. The same applies to document DE 60 2004 002 024 T2. A strapping method according to the preamble of claim 1 is disclosed in document DE 10 2008 031 236 A1.

[0009] It is desirable to optimise 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

[0010] It is generally suggested to replace the PLC of a strapping machine with a microcontroller. Microcontrollers are semiconductor chips that contain a processor and additional components that perform additional peripheral functions. A microcontroller typically contains RAM and program memory. It is often referred to as a single-chip system or "system-on-a-chip."

[0011] In combination with the existing but also new drive systems, measuring sensors and other elements of the strapping machine, the use of a microcontroller enables completely new methods for carrying out the strapping or for the flexible modification of the strapping parameters. First aspect: Recording the strapping position

[0012] According to a first aspect of the development described here, a method for strapping objects is provided, which comprises the following steps: • Transporting an object by means of at least one conveyor device to a strapping station, • Formation of at least one loop of strapping band around the object by means of a strapping device, • Connecting the ends of the loop together, wherein at least one position detecting means detects the position of the object.

[0013] To optimize the strapping position, the process also includes the following steps: • a detection device detects the conveying direction and conveying distance of the conveying device, • the signals of the detection device and the position detection means are transmitted to a control unit, • the control unit controls the conveyor device on the basis of the transmitted signals in such a way that the object is transported to at least one strapping position in which the loop of strapping band is formed on the object at a predetermined loop position.

[0014] In other words, based on the position of the object detected by the position detection device, the precise position of the object can be calculated at any time by detecting and monitoring the conveying path and conveying direction of the conveyor device. The signals from the detection device are transmitted to a control unit, which, based on this movement data, controls the conveyor device so that the object is transported to one or more predetermined strapping positions. In the strapping position, the control unit activates the strapping process so that the loop is applied precisely at the specified position.

[0015] Previous PLC-controlled strapping machines from the applicant were controlled exclusively via time programming. The programmed time could be reprogrammed if incorrect strapping positions on the objects were detected. However, it was not possible to select the optimal strapping position for different objects at any time, depending on the dimensions of the object or other conditions, or to correct the positioning based on the signals from the position detection device or the drives for the object.

[0016] In practice, the position detection means can detect the position of the leading edge of the object and the loop position can be stored in the control unit as a predetermined distance from the leading edge. In many practical cases, a first strapping is defined at a fixed distance, e.g. 10 cm, from the leading edge of an object to be strapped, such as a parcel. Furthermore, the leading edge of a parcel during transport to the strapping station is the first parcel section to be detected by a position detection means at a fixed distance from the strapping station. Using the detected leading edge provides the control unit with information about the next arriving object to be strapped at the earliest possible time. The necessary precautions can therefore be taken to initiate the optimal strapping process.

[0017] It is important to note that the conveyor system should not be stopped abruptly once the object to be strapped has reached the specified position in the strapping station. If the conveyor system were to stop abruptly, the object to be strapped would continue to slide forward on the conveyor system due to its inertia. This sliding action would disrupt the exact position of the object to be strapped in the strapping station and make it unpredictable. Furthermore, excessive braking, particularly with an object consisting of stacked elements, poses the risk of tipping over.

[0018] The conveyor device must therefore be stopped smoothly. For this purpose, so-called speed ramps are specified, which achieve a steady decrease in the conveyor speed with, preferably, a constant deceleration. The specified ramp, which defines the degree of the speed reduction (deceleration), prevents excessively high negative accelerations. Ramps can also be defined for the acceleration of the object to be strapped to prevent excessively high positive acceleration values.

[0019] Controlling the movement of the conveyor device based on the signal for the leading edge arriving first at the strapping machine makes it possible to target any position in the conveying direction of the object after this signal has been detected. It is desirable to detect the leading edge signal as early as possible in order to have a certain period of time for calculating the control and regulation parameters. In order to make this period as long as possible, in practice a first position detection means can be arranged at a great distance from the strapping station on the strapping machine and can detect the position of the leading edge of the object there. If the strapping machine has an infeed conveyor and an outfeed conveyor, the first position detection means can, for example, be arranged at the beginning of the infeed conveyor, i.e. at the end of the infeed conveyor which is the greatest distance from the strapping station.

[0020] However, with such a large distance between the position detection means and the strapping station, deviations can arise between the conveying path of the conveying device, in this case the infeed conveyor, and the movement path of the object to be strapped. The object to be strapped can, for example, be transported from an upstream conveying unit, e.g. from an accumulation conveyor, to the conveying device of the strapping machine. The upstream conveying unit can have a different conveying speed than the conveying device of the strapping machine. In this case, it depends on the size of the friction coefficient between the underside of the object to be strapped and the conveying device of the strapping machine on the one hand and the upstream conveying unit on the other hand whether the object moves at the speed of the upstream conveying unit or the speed of the conveying device of the strapping machine.

[0021] It is to be expected that a certain amount of slippage between the conveyor device and the object to be strapped cannot be ruled out. Consequently, the movement of the object's leading edge will not exactly correspond to the movement of the conveyor device. A second position detection device can be arranged near the strapping station and detect the position of the object's leading edge. Using the value of the object's leading edge detected by the second position detection device, the value of the detected conveyor distance can be checked and, if necessary, corrected. In general, the control unit can also perform control tasks depending on the measured values.

[0022] In other words, a rough control of the conveyor's conveying process is performed by detecting the position of the item's leading edge, which is detected at a considerable distance from the strapping station. The item is transported to the strapping station and guided a certain distance through the strap guide frame in the strapping station so that it can be strapped at the specified position. When the leading edge arrives in the area of ​​the strapping station, it is detected again, and the value of the conveying distance can be corrected using the value of the actual leading edge position. The slippage, which would change the exact position of the strap, is calculated out.At the time the leading edge is detected near the strapping station, the object to be strapped will be carried largely exclusively by the conveyor device of the strapping machine, so that from this point onwards the speed of the object essentially corresponds exactly to the speed of the conveyor device of the strapping machine.

[0023] Alternatively or additionally, the position detection means can detect the position of the trailing edge of the object, and the loop position can be stored in the control unit as a predetermined distance from the trailing edge. Again, multiple position detection means can be provided to measure the trailing edge in order to, if necessary, compare the distance traveled by the object with the movement of the conveyor. Position detection means, such as light barriers, can also be arranged in upstream conveyor units so that the length of the object to be strapped is determined well before it arrives at the strapping station. The length of the object and thus the position of the trailing edge can be sent to the control unit as part of the package accompanying data.

[0024] Furthermore, containers or packaging with predetermined dimensions, in particular predetermined lengths, can be used, with machine-readable markings such as printed codes or RFID transponders attached to the items. Either the length value is encoded in the information of the RFID transponder or the machine-readable code (barcode or QR code) and can be read by a reading device at or near the strapping station. Alternatively, an identifier assigned to the item, which is associated with specific dimensions and, in particular, length values, is stored in the RFID transponder or the printed code.

[0025] Additionally, detecting the position of the trailing edge is also helpful for determining the exact positioning of the object to be strapped and for correcting the position values ​​determined from the conveyor's movement data. Especially if the position detection device detects the position of the leading edge and the trailing edge of the object, the loop position can be specified in the control unit as the center between the leading edge and the trailing edge. Common strapping arrangements for longer objects often include center strapping.

[0026] Furthermore, in practice, the object can first be transported by the conveyor device to the position detection device until the front edge is detected, then transported further until the rear edge is detected, whereby the length of the object is determined from the conveyor path and the object is then transported to the strapping position. If necessary, the object can be transported back if the length of the object is greater than the distance between the strapping station and the furthest position detection device. Even with this type of measurement of the object, if several position detection devices are present at different locations on the strapping machine, the measured value of additional position detection devices can be used to correct the length data determined by the conveyor path.

[0027] When strapping longer objects, the object can be transported to several strapping positions, each of which forms a loop on the object. For example, a typical strapping of a longer object has a loop near the leading edge, e.g., at a distance of 10 cm, and a loop at the same or a similar distance from the trailing edge. For even longer objects, a loop is added in the middle of the object. Finally, it is common to apply multiple strapping near the leading edge, near the trailing edge, or in the middle of the object, in which, for example, two, three, or four loops are arranged at close intervals of the order of 10 mm.The object can also be transported to a first strapping position and provided with a loop at a specified distance from the front edge. It can then be transported further by specified distances to the next strapping position and provided with a loop. This process is repeated until the distance between the strapping station and thus the resulting distance of a loop from the rear edge of the object to be strapped falls below a certain limit, i.e., becomes too small.

[0028] If the package length is measured in the strapping machine or in the upstream conveyor units, or if the package length is transferred to the strapping machine as a data set with package accompanying data, an optimal strapping pattern can be calculated individually for the package. For this purpose, a first loop position with a specified distance from the front edge (e.g. 10 cm) and a second loop position with a specified distance from the rear edge can be specified. This determines the distance between the front and rearmost loop. This distance can be divided by a target distance between two consecutive loops. The resulting value can be truncated or rounded and forms the number of loops to be attached. The distance between the front and rearmost loop is divided by the resulting whole number, and the resulting value defines the distance between two consecutive loops.After each strapping, the object is conveyed forward by this distance.

[0029] In practice, a detection device can detect at least one property of the object. Data specifying the property of the object can be forwarded to the control unit, and the control unit can determine at least one target value for the loop position from the data specifying the property of the object. In its simplest form, the detection device can be formed by the position detection means, usually a light barrier consisting of a light source and a light sensor. In this case, the detection device enables the detection of the length as a property of the object as it is transported through. However, the detection device can alternatively or additionally be selected from • a barcode scanner for scanning a barcode attached to the object; • a reading antenna for reading an RFID transponder attached to the object; • a camera to capture the optical characteristics of the object.

[0030] If a unique, machine-readable identifier, such as a barcode, a QR code, or an identifier stored in an RFID transponder, is attached to the object, this can be read at the beginning of the strapping process or shortly beforehand. The characteristics assigned to the object that are significant for the strapping process (length of the object, height of the object, tension force for the strapping band, sensitivity to acceleration and maximum acceleration values, etc.) can be stored and retrieved in a central data storage unit. Based on the length of the object, for example, the control unit can calculate optimal target values ​​for the loop positions. Alternatively, the target values ​​for the loop positions can also be stored and assigned to the identifier and read out simply by retrieving the data assigned to the identifier.

[0031] A camera for capturing the optical characteristics of an object can be used in a variety of ways to control the strapping process and, in particular, to determine the loop position. The camera can be mounted on the strap guide frame, for example. By analyzing the image captured by the camera, the package length can be determined, for example. The target values ​​for the loop position are determined either by calculating them based on the package length or by retrieving them from a data storage device in which various loop positions for different package lengths are stored. Alternatively or additionally, a machine-readable code on the object can be identified and read in the image captured by the camera.The machine-readable code can either contain an identifier for the object, to which properties of the object or direct target values ​​for the loop position are stored in a data memory. The target values ​​for the loop position are then determined either by reading them from the data memory or by evaluating the property or properties and assigning or calculating corresponding target values. Alternatively or additionally, the target values ​​for the loop positions can be directly encoded in the machine-readable codes. Machine-readable codes such as barcodes or QR codes are coded alphanumeric character strings that are printed on a surface in machine-readable form. These character strings can contain the distances of the loop positions, for example from the front edge, the rear edge or the center of the package, in particular as metric values, e.g. as a numerical value that represents the distance in millimeters.

[0032] When a camera is used as a recognition device, many other properties of the object can be recognized. For example, an address field or a machine-readable code on the object can be recognized. For example, newspaper packages are often provided with a cover sheet on which the recipient's address information is printed alphanumerically and / or in machine-readable form (barcode, QR code). If a strapping band is placed over these address fields, the automatic reading of the address can be hindered. By evaluating the camera image, the position of areas that should not be covered can be determined. If target values ​​for the loop position lie within these areas, they can be changed so that strapping positions lie outside the address fields or other areas not to be strapped.

[0033] As mentioned, there are limits to the positive and / or negative acceleration by the conveyor device for certain objects to be strapped. For example, stacks of newspapers must not be accelerated to such an extent, at least before strapping, that the stacked newspapers slip relative to one another. In practice, the positive and / or negative acceleration of the conveyor device can be numerically set by the control unit to a value permissible for the respective strapping process. Simultaneously with the control of the strapping position, the control system therefore determines the timely start of deceleration of the object so that the permissible amount of acceleration is not exceeded. The permissible value of the acceleration can also be readjusted for each strapping process depending on the detected properties of the object to be strapped.

[0034] According to this first aspect, the present development also relates to a strapping system for strapping objects with the following features: • at least one conveyor device for transporting an object to a strapping station, • at least one strapping device for forming a loop of strapping band around the object, • at least one connecting device for connecting the ends of the loop to one another, wherein at least one position detecting means detects the position of the object.

[0035] In order to implement the method described above, the strapping system further comprises: • a detection device for detecting the conveying direction and conveying distance of the conveying device, • a control unit to which the signals of the detection device and the position detection means are transmitted, wherein the control unit is configured to control the conveyor device on the basis of the transmitted signals in such a way that the object is transported into at least one strapping position in which the loop of strapping band is formed at a predetermined loop position on the object.

[0036] The strapping system may comprise a first position detecting means at a great distance from the strapping station and a second position detecting means close to the strapping station, wherein the value of the detected conveying distance of the conveyor device is checked and, if necessary, corrected by the value of the position of the front edge of the article detected by the second position detecting means.

[0037] The position detection means can be selected from the following devices: • a light barrier arranged above the conveyor device, consisting of a light source and a light sensor; • a light barrier strip arranged above the conveyor device, consisting of several spaced-apart light sources on a first side of the conveyor and several correspondingly spaced-apart light sensors on a second side of the conveyor opposite the first side; • a camera that records the area above the conveyor device.

[0038] A single light barrier is typically positioned a short distance above the conveyor or an upstream conveyor unit to also detect the leading edge of flat objects passing through. A light barrier strip has the advantage over a standard light barrier in that it can also detect the height of objects if the light sources are distributed across the possible height range. If the light sources are arranged horizontally next to one another, the length can be detected. The combination of a horizontal and a vertical light barrier strip allows both length and height to be detected.

[0039] A camera is now a cost-effective means of position detection. If the camera is arranged to the side of the conveyor, a marking can be attached to the opposite side of the conveyor so that the camera can determine the exact position of the front edge of an object when the marking is covered by the front edge. The rear edge can also be determined when the marking is visible again. Height markings above the conveyor allow the height of the transported object to be recorded with a camera. With a stationary camera on the strapping machine, an absolute position value can be assigned to each pixel recorded by the camera. In this case, the markings can be omitted because the extent of the object up to a specific pixel can be directly assigned to a position value.

[0040] In practice, the detection device for detecting the conveying direction and conveying distance of the conveyor device can be selected from • at least one rotary encoder which emits electrical signals when a shaft of a drive motor of the conveyor device rotates; • an increment disk, the rotary movement of which is coupled to the rotary movement of a shaft of a drive motor of the conveyor device and an increment sensor which generates signals generated by the movement of the increment disk, wherein preferably the increment disk has alternating transparent and opaque sectors and the increment sensor is a light barrier.

[0041] Modern drive motors are already equipped with rotary encoders that emit signals associated with the motor's rotational movements. These signals are, in particular, electrical pulses that are generated after the shaft rotates by a predetermined angular amount. The signal emitting devices can, for example, be Hall sensors that detect the positions of drive motor elements coupled to the motor shaft (e.g., the rotor poles). Commercially available drive motors, for example, generate 15 signals per revolution of the motor shaft. A reduction gear is interposed to drive a drive roller of the conveyor device. This reduction gear has a reduction ratio of 36 / 1, for example, resulting in 540 signals per revolution of the drive roller, or 3 signals per 2 degrees of rotation of the drive roller.With a drive roller diameter in the range of 5-10 cm, the distance between two signals corresponds to the conveying distance of the object, between 0.3 and 0.6 mm. This allows for sufficiently precise positioning of the object. The accuracy of position control can be further increased by using incremental discs made of transparent glass or plastic with closely spaced opaque increments that can be detected by at least one light barrier.

[0042] As mentioned above, a strapping system according to the development described here can comprise a recognition device for recognizing at least one property of the object, which forwards data specifying the property to the control unit, which uses this data to determine at least one target value for the loop position. The recognition device can be a scanner for reading a printed machine-readable code or a reading antenna for reading an RFID transponder. Alternatively or additionally, the recognition device can be a camera that captures optical features of the object, including identifying and reading printed codes. Second aspect: Motion detection for strapping aids

[0043] According to a second aspect of the present development, a method for strapping objects is proposed, comprising the following steps: • Transporting an object using a conveyor device to a strapping station, • Formation of at least one loop of strapping band around the object by means of a strapping device, • Connecting the ends of the loop together, • Actuating at least one drive device for at least one strapping aid before or during the strapping process.

[0044] To optimize the control of the strapping aid, the method may further comprise the following steps: • a movement detection unit continuously records the movement data of the strapping aid, • the movement data is transmitted to a control unit, • the control unit controls the drive device for the strapping aid using the movement data based on numerically specified target values.

[0045] Similar to controlling the movement of the object to be strapped on the conveyor, angle encoders on the drive motors for the strapping tool can be used to record the distance and direction of movement. In other words, the control unit has information about the location of the strapping tool at all times. As described in detail below, the control unit can control the movement of the strapping tool so that the strapping process can be completed in the shortest possible time and an optimal strapping result can be achieved.

[0046] Powered strapping aids on strapping machines that optimize the alignment and position of the object to be strapped during the process include stops, hold-down devices, and / or packing presses. A stop is an object that can be moved into the path of travel of the conveyor. The conveyor transports the object until it rests against the stop. Typically, the conveyor continues to convey, slipping under the underside of the object. The frictional forces between the conveyor and the underside of the object press the object against the stop and thus align it. Usually, two stops are provided on either side of the centerline of the conveyor so that the object is aligned along a line perpendicular to the conveying direction. A hold-down device is a movable bar that is moved onto the top side of the object to be strapped.For example, if the item to be strapped is a stack of magazines, this ensures that the top pages of the magazine stack lie flat against each other and are not damaged by the strap loop. A packing press works on a similar principle, but exerts greater force on the item to be strapped, compressing it. After strapping, the item cannot rebound due to the attached loops of strong strapping tape.

[0047] In practice, the strapping aid can be moved by the drive device to a reference position, and the motion detection unit can record the movement data of the strapping aid in relation to this reference position. The signals emitted by the drive motors of the drive devices, which are dependent on the angle of rotation, make it possible to determine the direction and, in predetermined incremental steps, the amount of rotation of the motor shaft. From this, a value for the direction and amount of displacement of the driven strapping aid can be directly calculated, taking into account the gear ratios of the motion transmission means. An absolute position cannot be derived from the signals from the drive motors. At the latest when the strapping machine is switched off and then switched on again, the control unit no longer has information about the absolute position of the strapping aid(s).For this reason, the strapping aid is moved to a reference position, for example, against an end stop. The end stop can be equipped with a switch that sends a signal to the control unit. When the control unit receives this signal, the position of the strapping aid is known. However, one or more sensors can also be arranged along the strapping aid's path of movement, each of which sends a signal as the strapping aid moves past. The signal from each sensor indicates that its assigned reference position has been reached.

[0048] According to the state of the art, the strapping aids were moved against the end stop after each strapping process. With this development, the absolute position of the strapping aids is known during operation, so that the strapping aids can be controlled to the most favorable target values ​​based on their positions determined from the movement data, and do not have to be moved against the end stop at the end of each strapping process.

[0049] In practice, a detection device can detect at least one property of the object transported by means of the conveyor device and the drive device of the strapping aid can control the setpoints for controlling the drive device depending on the detected property.

[0050] In other words, properties such as the width or height of the object to be strapped can be recorded. Depending on the height of the object, the target height is determined to which the hold-down device or the packing press must be moved to enable the feeding or removal of the object to be strapped. The target height can be selected a few millimeters or centimeters above the top edge of the object to be strapped. The same applies to a packing press.

[0051] In the case of a stop, the width of the objects to be strapped can be recorded as a property. The stops on the applicant's strapping machines are moved laterally into the conveyor line. Depending on the width of the object, the target values ​​for the stop positions can be a few millimeters or centimeters outside the width of the object to enable trouble-free transport of the object to be strapped through the stops.

[0052] Because the strapping aids are moved only slightly out of the path of travel and out of the contour of the object to be strapped, the distance the strapping aids must travel between two consecutive strapping operations is significantly reduced, and thus the time required for the strapping aids' movement is also reduced. Since the mechanical strapping of objects in automated production systems is extremely time-critical, this reduction in the time required for secure strapping can reduce the overall time required to produce a given quantity, increase productivity, and consequently lower production costs.

[0053] As already mentioned, the stops fed into the conveyor belt from the side also serve to align the object to be strapped. The object is moved against the stops by the conveyor device. The conveyor device is also moved further when the object rests against at least one of the stops, so that the friction on the underside of the object creates a force that pushes the object towards the stops. If the object is aligned at an angle to the stops, its front edge will only rest against one of the two stops. Due to a lever arm between the resultant of the friction forces of the conveyor belt, which usually runs through its center, and the counterforce exerted by one of the stops, a torque is generated which rotates the object into the intended position so that it also rests against the second stop.This torque is greater the greater the distance between the two stops and the center line of the conveyor belt.

[0054] By detecting the width of the object, the stops can be controlled to a target distance between the stops that is only slightly smaller than the width of the object. This ensures that the two stops are positioned as far outward as possible against the leading edge. This results in the highest possible torque and the most reliable alignment of the object on the conveyor.

[0055] In practice, the control unit can shut down the drive device if the recorded movement data deviates from a target value by an unacceptable amount, or actuate it in the opposite direction. As explained above, the movement detection unit detects the movement of the strapping aids by evaluating the motor signals, which represent the degree of rotation of the drive motor's motor shaft. Since the microcontroller also has a processor clock, the movement data can be related to time and converted into the current speed or acceleration. For the driven strapping aids, in particular the hold-down devices and packing presses pressed from top to bottom against the objects to be strapped, the speed profiles are known during trouble-free operation or can be determined through test runs. These target speed profiles can be saved.In addition, it is known in which position a strapping aid comes into contact with the object to be strapped if, as described above, properties such as the width and height of the object have been detected by a detection device.

[0056] If the speed or acceleration of the strapping tool deviates from a target value before contacting the object to be strapped, especially if the speed is noticeably below the target speed, this may be a sign that an object or person is obstructing the movement of the strapping tool. To avoid damage or injury and increase safety, the drive of the strapping tool can be switched off immediately or even moved back a certain distance. An excessively high speed value can also indicate problems, such as damage to the coupling between the drive motor and the strapping tool or the absence of an object to be strapped. In this case, too, stopping the strapping tool, ideally coupled with a signal to alert personnel, is helpful.

[0057] According to this second aspect of development, a strapping system for strapping objects can have the following features: • at least one conveyor device for transporting an object to a strapping station, • at least one strapping device for forming a loop of strapping band around the object, • at least one connecting device for connecting the ends of the loop to each other, • at least one drive device for driving at least one strapping aid before or during the strapping process.

[0058] To optimize the function of this strapping system with strapping aid, the system can be characterized in that a movement detection unit continuously records the movement data of the strapping aid and transmits these to a control unit, wherein the control unit controls the drive device on the basis of numerical target values ​​by means of the movement data.

[0059] The strapping aids mentioned may comprise one or more of the motor-driven additional units of the strapping machine, in particular a stop, a hold-down device or a packing press.

[0060] As explained above, a detection device can be provided that detects at least one property of the transported object, with target values ​​for controlling the drive device of the strapping aid being determined depending on the detected property (e.g., height or width of the object to be strapped). However, additional target values, such as the contact force, can also be determined depending on other properties, such as the strength of the object.

[0061] In particular, the control unit can control the drive device for the strapping aid such that, depending on the detected property, in particular the height or width of the object to be strapped, the strapping aid is only moved out of the object's transport path after the strapping process to such an extent that free further transport of the object is possible. As mentioned above, the strapping aids (stops moved laterally into the transport path or packing presses and hold-down devices moved from top to bottom) only need to be moved back to such an extent that the fully strapped object and the next object to be strapped can be transported freely past the strapping aids. Moving the strapping aids back to their stop positions at the maximum distance from the transport path is not necessary.

[0062] In practice, the control unit can be designed to switch off the drive device or to operate it in the opposite direction in the event of an inadmissible deviation from a target value for the movement data, in particular the speed and acceleration of the strapping aid. Third aspect: Strapping position editor

[0063] According to a third aspect of the development described here, a method for strapping objects is proposed, comprising the following steps: • Transporting an object using a conveyor device to a strapping station, • Formation of at least one loop of strapping band around the object by means of a strapping device, • Connect the ends of the loop together.

[0064] To enable the correct setup of the strapping machine even for less experienced users, the procedure is characterized by the following steps: • Displaying a representation of the object on a display device; • Marking of at least one desired strapping position on the representation of the object by manual input; • Conversion of the marked strapping position into numerical data to determine the loop position on the object, • Transmission of the numerical data of the loop position to a control unit for positioning the object; • the control unit controls the conveyor device on the basis of the transmitted data in such a way that the object is transported to at least one strapping position in which the loop of strapping band is formed at a predetermined loop position on the object.

[0065] In other words, a graphical editor is provided with which the strapping position is determined by manually entering a marker on the representation of the object to be strapped and converted into strapping positions that can be reached by the strapping machine. Such a procedure was unthinkable for previous strapping machines with PLCs. The PLC could only be reprogrammed by experienced personnel to enable time-controlled approach to different strapping positions.Since, according to the development described here, it is possible to approach strapping positions with millimeter precision due to the monitoring of the movement data of the drive motor for the conveyor device, and since the microcontroller can variably implement different strapping sequences based on new setpoints, a simple editing tool can be created here with which the user can define the strapping positions to be approached by the machine by simply marking positions in the displays on the screen.

[0066] In practice, at least one strapping aid can also be displayed on the display device, and a position of the strapping aid can be marked in the displayed representation by means of a manual input. The marked position is converted into position data for the control unit and transmitted to it. Thus, the user can define target positions for the strapping aids in addition to the strapping positions.

[0067] Manual input is performed using a standard computer input device, such as a mouse, touchpad, or trackball, or by touching the surface of a touch-sensitive display. The target values ​​for the strapping can also be entered numerically via a keyboard and then displayed on the display in the representation of the object. Fourth aspect: Data sets with target values ​​for strapping parameters

[0068] According to a fourth aspect of the development described here, a method for strapping objects comprises the following steps: • Transporting an object using a conveyor device to a strapping station, • Formation of at least one loop of strapping band around the object by means of a strapping device, • Connecting the ends of the loop together, • Control of the strapping parameters, which include at least the strapping position, by means of a control unit.

[0069] To individually adapt and optimize the strapping process to the respective object to be strapped, the procedure can be characterized by the following steps: • Saving data sets with target values ​​for the strapping parameters in a data storage device connected to the control unit; • Selection of a data set with target values ​​for the strapping parameters for each strapping process by the control unit.

[0070] In other words, entire strapping recipes are stored in a data storage device connected to the control unit, i.e. data records in which the strapping positions but also other target values ​​relevant for strapping, such as the maximum acceleration of the object to be strapped and the tensioning force of the strapping band, are stored.

[0071] For each strapping process, a data set containing target values ​​for the strapping parameters can be selected and applied to the strapping process by the strapping machine's control unit. Of course, a data set can be used for multiple consecutive strapping processes. The key point is that whenever the properties of the object to be strapped change, different strapping parameters can be used.

[0072] Such a procedure is difficult to imagine with PLC-controlled machines. In this case, the strapping machine would have to be shut down and the control system programming would have to be changed by experienced service personnel. On strapping machines with a microcontroller, the strapping parameters can be flexibly changed for each strapping process. Of course, the data sets containing the target values ​​for the strapping parameters can also be calculated during the feeding of the object to be strapped based on detected properties (length, height, width, weight, etc.) of the object to be strapped and stored in the control unit's RAM. This also represents a form of flexible adjustment of the strapping parameters for each strapping process in which the properties of the object to be strapped change.

[0073] It is also possible for a data set containing target values ​​for the strapping parameters to be transmitted to the control unit as package accompanying data and used during the strapping process to select a data set containing target values ​​for the strapping parameters. In other words, the data sets containing the optimal strapping parameters can be defined well in advance of the strapping machine or the actual strapping process, for example, in conjunction with standard properties of standard packaging. These target values ​​can then be transmitted to the control unit either as a data set together with the corresponding item or from a central control computer via data lines to an interface of the control unit for each package to be strapped.Alternatively, a plurality of data records can be stored in a central data storage device associated with an identifier, with the identifier being attached to the object to be strapped. A printed machine-readable code (barcode, QR code, etc.) or an RFID transponder is particularly suitable as an identifier. The identifier is read by a reading device on the strapping machine, and the data record to be used is retrieved from the central data storage device using the identifier.

[0074] The strapping parameters can also be stored directly in the machine-readable code or in the transponder's data memory. A suitable reading device, such as a reading antenna for the RFID transponder or a camera or scanner for reading the printed machine-readable code, is then attached to the control unit.

[0075] However, the method according to the above-mentioned fourth aspect of the invention can also be implemented by the following steps: • Recognizing at least one property of the object by a recognition device and transmitting the data specifying the property of the object to the control unit; • Selection of a data set with target values ​​based on the data specifying at least one property of the object by the control unit.

[0076] In other words, the length, height, width, etc. of the package can be detected, and a data set defined for specific value ranges of length, height, and width can be retrieved from the machine's data memory. However, the data set with target values ​​can also be selected by calculating the target values, taking into account at least one of the detected properties (length, height, width, weight, etc.).

[0077] In practice, the data set may include target values ​​for at least one of the following strapping parameters: • Distance of the strapping position from the front edge of the object; • Distance from the strapping position to the rear edge of the object; • Number of strappings; • Strap tension; • Position of a stop during the strapping process; • Position of the stop during transport of the object; • Position of a hold-down device or packing press during transport of the object; • Pressure force of the hold-down device or the packing press during the strapping process.

[0078] The at least one property of the object can be recognized by at least one of the following recognition devices: • Light barrier; • Light barrier strip, consisting of spaced-apart light sources on a first side of the conveyor and a plurality of correspondingly spaced-apart light sensors on a second side of the conveyor opposite the first side; • Reading device for printed code; • Reading antenna for RFID transponders; • Camera.

[0079] The use of a camera as a recognition device allows the recognition of several properties, in particular the recognition of address fields, printed barcodes and other areas on the surface of the object to be strapped, which must not be covered by a strapping band.

[0080] According to the fourth aspect of the invention, a strapping system for strapping objects is also proposed, which has the following features: • at least one conveyor device for transporting an object to a strapping station, • at least one strapping device for forming a loop of strapping band around the object, • at least one connecting device for connecting the ends of the loop to each other, • a control unit for controlling several strapping parameters, including strapping position and tension of the strapping band applied around the object.

[0081] For individual adaptation and optimization of the strapping process to the respective object to be strapped, this strapping system can be characterized in that a data memory is provided which is connected to the control unit and supplies the control unit with data sets with target values ​​for the strapping parameters.

[0082] The strapping system can comprise the above-described detection device for detecting at least one property of the object and for transmitting the data specifying the property of the object to the control unit, wherein the data is used to select a data set with target values ​​for the strapping parameters based on the at least one property of the object. The properties that can be detected, for example, with the detection device, as well as the strapping parameters that can be controlled, for example, with the control unit, have already been mentioned above. The same applies to the technical devices that can be used as detection devices. Fifth aspect: Control of the main shaft of the closure unit

[0083] According to a fifth aspect of the present development, a method is proposed for strapping at least one object with a strap loop on a strapping machine with a closing unit, wherein the closing unit has at least a first clamp for the front end of the strap loop, a second clamp for the rear end of the strap loop and a welding device, wherein at least one strap loop is formed from a strapping band around the object, tensioned and closed by the closing unit, wherein a main shaft moves at least the clamps and the welding device via cam disks and is rotated into at least one predetermined angular position by a drive motor during the closing process.

[0084] Controlling the sealing unit via such a main shaft, often also called a king shaft, has proven to be very robust and reliable. The cams on the main shaft control the movement of the sealing unit's components very reliably. The clamps usually have a clamping punch moved by a cam on the main shaft, which is pressed against a counterbearing plate so that one end of the formed strap loop is clamped to the counterbearing plate. They also move the welding device of the strapping machine against the areas of the strapping band to be welded between the clamps. The welding device often consists of a fusion welding device with a heating element that locally melts the plastic material of the strapping band.Alternatively, ultrasonic welding devices are used, which introduce energy into the strip material via sonotrodes, thereby melting it in the contact area between the strip sections to be welded. Both welding devices must be brought into reliable contact with the strip sections to be welded.

[0085] Current main shafts are controlled by control cams. The control cams mark the achievement of a predetermined angular position. When the drive motor for the main shaft is switched off, the shaft remains in the predetermined angular position. However, it has been shown that the control cams lead to a certain dispersion of the angular positions actually reached by the main shaft. The torque required to drive the main shaft varies. This torque changes significantly due to the cam disks on the main shaft. If the cam disk moves a plunger against a return spring or even compresses it elastically to generate sufficient contact pressure, the required drive torque is high. If the cam disk guides the plunger in the direction of the return spring force, the torque becomes small or negative. The same applies to the actuation of other components of the locking unit.

[0086] With a low torque, which counteracts the drive torque of the drive motor, the stopping distances for the drive motor are relatively long. With a high torque, the stopping distances are shorter.

[0087] The static factors that influence the stopping distance of the main shaft can be compensated by adjusting the static positioning of the control cams.

[0088] However, the resistance to rotation of the main shaft is also influenced by variable factors such as temperature, humidity, lubrication of the strapping machine components, lubricant age, contamination, and wear. All of these factors affect the stopping distances. They can change rapidly. The temperature and humidity in the environment of a strapping machine can change significantly within a few minutes, resulting in the aforementioned variation in the actual angular position of the main shaft, which is achieved by means of the cam control, during operation of the strapping machine.

[0089] It is desirable to improve the control of the main shaft and, in particular, to be able to compensate for the influence of variable factors.

[0090] This is achieved through the following steps: • a detection device detects the angle of rotation of the main shaft, • the signals from the detection device are transmitted to a control unit, • the control unit compares a setpoint for the angular position with the actual value of the angular position determined from the transmitted signals, • the control unit changes the control of the drive motor if there are deviations between the setpoint and the angle of rotation detected by the detection device.

[0091] In other words, while the main shaft is rotating, a signal is continuously transmitted from the detection device to the control unit, representing the angle of rotation of the main shaft. The direction of rotation can also be determined from the signal, since the main shaft can be rotated in the opposite direction if necessary, e.g. in the event of a malfunction. As soon as the drive motor has rotated the main shaft to the specified angular position, the control unit compares a stored target value for the angular position with the actual value of the angular position determined from the transmitted data. If the actual value deviates from the target value, the control of the drive motor is changed. This can already occur when approaching the next angular position.Generally, during each closing process of a strap loop, the main shaft moves to a plurality of angular positions. These angular positions are assigned to different processing steps in the creation and tensioning of the strap loop around the object to be strapped and in the welding of the loop ends. If the first angular position reached deviates by a certain amount from the target value, the stop process for the main shaft drive motor can be initiated earlier or later accordingly in order to precisely achieve the target value for the second angular position. Alternatively or additionally, the control device can modify the drive motor control for the next approach to the same angular position.

[0092] The proposed adaptive control of the drive motor, which depends on measured deviations between the target position and the actual position, allows for maximum precision in controlling the specified angular positions, resulting in optimal control of the target values ​​of the angular positions at all times, even under changing conditions. Optimally achieving the target values ​​of the angular positions also ensures optimal function of the components actuated by the main shaft.

[0093] In practice, the cam discs of the main shaft can move a large number of components involved in the strapping process, the most common of which are listed below.

[0094] The closing unit has clamps, each with a clamping punch that can be pressed against an abutment plate to secure each end of the strap loop. A first clamp secures the front end of the strap loop after the strap loop has been formed. A second clamp secures the rear end of the strap loop after the strap loop has been tightened around the object. The welding device is located between the two clamps. The clamps of the closing unit can be moved by the cam disk on the main shaft from an open position, in which the clamping punches are at a distance from the abutment plate, to a clamping position in which the clamping punches are pressed against the abutment plate, and back again.

[0095] The sealing unit's welding device can be moved from an inactive position to a welding position by the cam. If the welding device is a fusion welding device with a heating element, the heating element, e.g., a heating tongue or a heating wedge, is moved against the two strapping sections to be welded. After heating, the heating element is retracted, and another die presses the strap sections to be welded together until they have cooled down and the weld is solid.

[0096] In an ultrasonic welding device, a sonotrode is moved against two superimposed strap sections, which are supported against a counterplate. The sonotrode is set into high-frequency vibrations, thus transferring energy to the weld. To cool the weld, the sonotrode's vibration is stopped, and the weld is cooled without further energy input. The sonotrode is then moved away from the strapping. Other welding devices are friction welding devices, which generate heat through friction caused by mechanical movement between the two strap sections to be welded.

[0097] At least one belt drive can be moved from an engaged position, by being coupled to transport rollers for the strapping, to a disengaged position in which there is no movement coupling between the belt drive and the transport rollers. Often two belt drives are present: a first drive that feeds the strap into the strap guide frame at high speed and retracts it, and a second belt drive, also called a tensioning drive, which tensions the retracted strap at low speed and high torque. The first belt drive with the low torque can be permanently coupled to the transport rollers for the strapping. The tensioning drive should be disengaged while the strap is being fed in and retracted at high speed. The engagement and disengagement of the tensioning drive is controlled by one of the cam discs.

[0098] Furthermore, an upper carriage of the sealing unit, which forms the abutment plate or abutment plates, can be moved from a closed position to an open position and back. In the closed position, it closes a gap in a support table of the strapping machine. The formed strap loop is welded in the area of ​​this gap by the sealing unit. In the open position, the upper carriage releases the gap, allowing the formed and closed strap loop to pass through the gap and rest against the strapped object.

[0099] If additional components are used in strapping an object, these can also be driven by the main shaft. However, it is also possible to drive additional components of the strapping machine, such as the closing elements for the strap guide frame, the stops, packing presses, and hold-down devices, with separate drives.

[0100] In practice, the main shaft can move to several angular positions during each strapping process. The first angular position is a reference position or synchronization position. In this reference position, a reference position marker is attached to the main shaft or connected to the main shaft, which interacts with a sensor whose signal is sent to the control unit. The sensor therefore detects a physical structure, e.g. a cam attached to the main shaft. The reference position can be passed through during each strapping process so that the actual values ​​of the rotation angles can be precisely recorded based on the signals from the detection device. However, the target value / actual value comparison does not take place in the reference position, since only one actual value is recorded here in order to rule out errors in the actual value calculation for subsequent angular positions.

[0101] A first angular position of the main shaft, which can be moved during the strapping process, is assigned to the retraction of the excess strap material. This angular position is controlled after the strapping band has been inserted into the band guide frame, after the free end of the band moves against and activates a sensor. In this position, the first clamp clamps the free end of the band. Furthermore, the drive direction of the first band drive is reversed to retract excess strap material.

[0102] Once the belt loop is slightly tensioned and the first belt drive stops with the low torque, another angular position is controlled, which corresponds to the tension of the belt material. For this purpose, the tension drive is pushed in by the main shaft.

[0103] The next angular position of the main shaft is assigned to the welding position. In this angular position, the second clamp is closed by pressing the second clamping die against the abutment plate to secure the second end of the tensioned strip loop, and a cutting edge cuts the strip loop from the strip supply. The second clamping die and the cutting edge are also actuated by cam discs on the main shafts. Furthermore, in this welding position, the welding device is moved into the welding position. In other words, the heating element is moved against the two strip sections to be welded. Alternatively, a sonotrode of an ultrasonic wave welding device is moved against the strip sections to be welded.

[0104] The next angular position of the main shaft is assigned to the cooling of the weld. In the ultrasonic welding device, this angular position can be identical to the welding position. To cool the weld, simply turn off the supply of ultrasonic energy through the sonotrode. In a fusion welding device with a heating element, the heating element is moved out of the weld in the cooling position, and the heated strip sections are pressed against each other by a punch. This punch can also be moved by the main shaft.

[0105] The next angular position is the opening position. In this opening position, all clamps are open and the welding unit moves away from the formed strap loop. The upper carriage, which carries the abutment plate, is moved out of the gap in the support table of the welding machine. The formed strap loop can now pass through the gap and move against the underside of the strapped object. In the opening position, the cover elements of the strap guide frame are usually also open. The opening position is therefore usually also approached as a fault position if problems arise during a strapping process. In this opening position, the strapping can be moved out of the strap guide frame and also pulled out of the sealing unit. Finally, a zero position is approached, in which all components of the strapping machine remain until the next loop is formed.In the zero position, the object to be strapped continues to be transported until a new loop is formed. Furthermore, in the zero position, the strapping band is inserted into the band guide frame. If the closing elements of the band guide frame are also actuated by the main shaft, they are in the closed position when the main shaft is in the zero position.

[0106] The reference position or synchronization position is preferably located between the zero position and the retraction position, so that it is passed through at the beginning of each new loop formation process and the position determination is adjusted.

[0107] In practice, the detection device for the angular position of the main shaft can be formed by a rotary encoder of the drive motor, which emits electrical signals, in particular pulses, when the motor shaft of the drive motor rotates. Sensors such as Hall sensors are arranged in the drive motors in a known manner and generate pulse signals as the motor shaft rotates. To generate the required torque, the drive motor can be connected to the main shaft via a reduction gear. In a practical embodiment, the rotary encoders of the drive motor emit on the order of 700 pulses for one revolution of the main shaft. The rotation of the main shaft can therefore be resolved with a precision of approximately 0.5 degrees. In this embodiment, as mentioned, the reference position, also called the synchronization position, is defined by a cam on the drive shaft, which is controlled by a dedicated sensor (e.g.Hall sensor). Synchronization or reference detection compensates for rounding errors or other errors in position determination, since the absolute angular position of the main shaft is known after each full revolution in the reference position.

[0108] Alternatively or additionally, the detection device can be an additional device, for example, one or more light barriers that interact with incremental disks mounted on the main shaft. Such incremental disks have alternating transparent and opaque sections and allow high-resolution rotation angle detection. Such an incremental disk can also contain a reference marking, so that in this case the reference position is applied to the incremental disk of the detection device.

[0109] The invention further relates to a strapping machine with a closing unit which has at least one clamp for the front end of the strap loop, a second clamp for the rear end of the strap loop and a welding device, wherein a main shaft moves at least the clamps and the welding device via cam discs and is rotated into at least one predetermined angular position by a drive motor during the closing process.

[0110] To optimize the control of the specified angular position, the strapping machine can have the following features: • a detection device that detects the angle of rotation of the main shaft, • a signal line via which the signals from the detection device are transmitted to a control unit for the drive motor, • a data memory assigned to the control unit, in which at least one target value for the angular position is stored, wherein the control unit changes the control of the drive motor in the event of deviations between the target value and the angle of rotation detected by the detection device.

[0111] The main shaft may have cams for moving at least one of the following components: • the clamp of the locking unit from an open position to a clamped position; • the welding device from an inactive position to a welding position; • at least one drive for the belt from an engaged position to a disengaged position, • an upper slide of the locking unit from a closed position to an open position.

[0112] The detection device can be a rotary encoder that emits electrical signals when a motor shaft of the drive motor rotates. A reference position marker can be connected to the main shaft, which interacts with a sensor whose signal is transmitted to the control unit. The welding device can be selected from: • a fusion welding device with heating element; • an ultrasonic welding device; • a friction welding device.

[0113] The features disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for implementing the invention in various embodiments. The invention is not limited to the described embodiments. It may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

[0114] 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. Fig. 2 - 5 show top views of a strapping machine and upstream and downstream accumulation conveyors. Fig. 6 shows a schematic plan view of the infeed conveyor and the outfeed conveyor of the strapping machine from Fig. 1. Fig. 7 shows a front view of a strap guide frame of the strapping machine with hold-down device. Fig. 8 shows a front view of a strap 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 shows a schematic representation of a second screen display for a strapping editor. Fig. 11 -13 show schematic graphic representation options for various strapping patterns. Fig. 14 and Fig. 15 show screen representations of so-called strapping recipes with target values ​​for all strapping parameters. Fig. Figure 16 shows the interaction of a strapping machine with a data storage for strapping recipes. Fig. 17 shows a front view of a sealing unit of a strapping machine. Fig. 18 shows a three-dimensional rear view of the closure unit from Fig. 17. Fig. 19 shows a three-dimensional representation of the main shaft of the closure unit from the Fig. 17 and Fig. 42 with drive motor and gearbox. Fig. 20 shows a side view of the main shaft with drive motor and gearbox from Fig. 19.

[0115] The Fig. The strapping machine 1 shown in Figure 1 is used to strap objects 7 with a strapping band 2, which is pulled from a supply roll (not shown) by a pull-in device 4 and fed to a band magazine 5. From there, the strapping band 2 is fed by means of a band conveyor device 6 through a tensioning device 8 into a band guide channel in a band guide frame 9, so that the band forms a loop. The band guide frame 9 is U-shaped with the opening at the bottom, so that the strapping band 2 is guided from the first side of the support for the object 7 by means of the band guide frame 9 in a U-shape around the object 7 to the other side of the support. As mentioned at the beginning, other shapes of the band guide frame and also other types of strapping are known, for example guiding the strapping band around using grippers and lances.What is essential in this development is that the strapping machine 1 creates a strap loop at a specific position. The strap is then retracted by the drive of the strap conveyor device 6 so that the strap loop lies tightly against the object 7. The tensioning device 8 is now activated so that the strap loop is pulled around the object 7 with a predetermined high tension force. The beginning of the loop is then connected to the end of the loop by means of a sealing unit 10. In practice, the sealing unit 10 consists of a welding device, e.g. an ultrasonic welding device, which welds the two ends of the formed packing strap loop together. Such a sealing unit is described, for example, in the document EP 1 479 611 A2. The sealing unit 10 welds the film-like plastic material from which the strapping band 2 is made.

[0116] The conveyor device for the object 7 is in Fig. 1 is not shown. A control unit 11 for the strapping machine 1 is shown in Fig. 1 on the right side of the strapping machine 1. The control unit 11 has a circuit board 3 with a microcontroller that controls or regulates the functions of all functional elements of the strapping machine 1. A part 12 of a plug connection is arranged on the control unit 11, which in this case is designed as a socket part 12 of the plug connection.

[0117] The control unit 11 also controls the drives for strapping aids, in particular additional units of the strapping machine 1. In Fig. 1, the first additional unit is a hold-down device 22, which presses down on the object 7 to be strapped from above. Further additional units are a left stop 25 and a right stop 26, which align the object 7 to be strapped before the strapping process. The two stops are attached to the strap guide frame 9 and driven in a counter-synchronous manner, meaning they are always at the same distance from the center of the strapping machine 1. The function of the stops 25, 26 is also described in more detail below.

[0118] The Fig. 2 - 5 show schematic top views of a strapping machine 1 with upstream and downstream accumulating conveyors 15, 16 and with the packages 7, 7' to be strapped. The strapping machine 1 itself has two conveyor devices. An infeed conveyor 13, which is Fig. 2 - 5 to the left of the belt guide frame 9, and an outlet conveyor 14, which is in the Fig. 2 - 5 is located to the right of the belt guide frame 9. The infeed conveyor 13 and the outfeed conveyor 14 each consist of a pair of synchronously driven conveyor belts. The upstream accumulating conveyors 15 and the downstream accumulating conveyors 16 can be any conveyor means, for example, belt conveyors or roller conveyors.

[0119] The conveying direction for the object 7 to be strapped, usually a package, is shown as an arrow above the input-side accumulating conveyor 15. Of course, the conveying direction of all conveyor devices can also be reversed.

[0120] All illustrations show a first position detection device 17 near the end of the infeed conveyor 13 furthest from the strap guide frame 9. The strap 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 Fig. 5 has a further position detection device 18 near the belt guide frame 9. A third position detection device 19 is arranged in this embodiment in the region of the end of the outfeed conveyor 14 remote from the belt guide frame 9. The position detection devices 17, 18, 19 typically 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 at 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.

[0121] The position detection means 17 located near the input-side accumulation conveyor 15 transmits a signal to the control unit 11 of the strapping machine 1 as soon as an article 7 is transported from the input-side accumulation conveyor 15 to the infeed conveyor 13. The infeed conveyor 15 is driven by a drive motor 57 ( Fig. 6) which has a rotary encoder. The rotary encoder generates signals at fixed angular intervals when the drive shaft of the drive motor 57 rotates, which are passed to the control unit 11. The signals are shown schematically in Fig. 6 is 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. Based on the phase offset, the different directions of rotation can be identified by the control unit. As explained above, the distance between two signals from the drive motor 57 can correspond to a conveying distance of the infeed conveyor 13 in the order of 0.3 to 0.6 mm. The outfeed 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 distance of an object on the outfeed conveyor 14 and allow the conveying direction to be identified.

[0122] Because the conveying direction and conveying distance of the infeed conveyor 13 and the outfeed conveyor 15 are detected, it is possible to determine the position of an object 7, 7' located on the conveyor devices 13, 14 of the strapping machine 1 at any time, starting from the first detection of the object's position as it passes the input-side light barrier 17. This position determination can be further refined by the second position detection means 18 and the third position detection means 19. Depending on the application, the upstream accumulation conveyor 15 can have a different conveying speed than the infeed conveyor 13 of the strapping machine. This can cause slippage between the conveyor belt of the infeed conveyor 13 and the object 7, 7' to be strapped. If the upstream accumulation conveyor 15 runs faster, the object 7, 7' to be strapped is moved forward faster than the conveyor belts of the infeed conveyor 13.If the accumulation conveyor 15 runs slower, the object 7 moves slower than the infeed conveyor 13 until its weight is essentially only borne by the conveyor belts of the infeed conveyor 13. If a second position detection means 18 is present near the belt 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 belt guide frame 9. This can compensate for any slippage that may exist between the object 7, 7' to be strapped and the infeed conveyor 13. A position detection means 19 can also be provided at the opposite end of the strapping machine 1, i.e. at the edge of the outfeed conveyor 14 remote from the belt guide frame 9 (see . Fig. 4 and Fig. 5). This then enables the strapping machine 1 to be operated in both directions. Furthermore, the position detection means 19 detects the trailing edge of the object 7 to be strapped during removal in the conveying direction shown and indicates when the strapping machine 1 is completely free for another object to be strapped.

[0123] 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 distance of the infeed conveyor 13. After the front edge of the object 7, 7' to be strapped has been detected, its position is continuously known because it can be calculated from the conveying distance and conveying direction of the conveyor device, i.e., the infeed conveyor 13. Near the strap guide frame 9, this position value can be corrected again if the second position detection means 18 is provided here. Due to the incremental signals emitted by the detection device for detecting the conveying direction and conveying distance, the position can be controlled with an accuracy of less than 1 mm. During further transport of the object 7, 7' to be strapped, the rear edge of the object 7, 7' to be strapped is also detected by the position detection means 17.Since the conveyor 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 disruptions caused by empty strapping. In previous strapping devices, the strapping positions were predetermined by the fixed timing of the strapping machine. If, for any reason, the object to be strapped was too short, a strap loop would still be formed. Such empty strapping can lead to malfunctions of the strapping machine. With this development, such disruptions 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, strapping can either be avoided at this position or the object 7, 7' to be strapped can be shifted by the control unit 11 of the strapping machine 1 such that the strapping position lies securely within the contours of the object 7, 7' to be strapped. Such a shifting can also occur if it is determined that a loop is to be created with too small a distance from the front edge or the rear edge of the object to be strapped.

[0124] By determining the length of the object to be strapped, it is also possible to precisely move to the center of the object 7, 7' to be strapped. Fig. 2 and Fig. 3 shows a first object 7 to be strapped, the length of which is already recorded when the first strapping is applied. The object 7' to be strapped in Fig. 5 is longer. Its total length can only be measured once its center has already been transported past the strapping plane of the strap guide frame 9. In this case, to determine the precise length of the object 7' to be strapped, the object can be moved to a position in which its length is known from the signal of the position detection device (light barrier) 17, because the rear edge of the object 7' to be strapped moves past the position detection device 17. The object 7' to be strapped can then be transported back to create a center strap exactly in its center.

[0125] If transporting the object 7' to be strapped in two directions requires two people, the machine control system can simply enable further transport and skip the center strapping. As described elsewhere, the length of the object 7' can also be determined in advance and transmitted to the control unit. In this case, center strapping is possible without the trailing edge of the object having passed through the light barrier 17.

[0126] The strapping patterns that can be created with this strapping machine can have any structure. Sample strapping patterns are described below.

[0127] In the Fig. 5 also schematically shows a recognition device 20 on the strap 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 that captures an image of the strapping zone below the strap guide frame 9. The camera can also identify and read printed codes in the captured image. Furthermore, a reading antenna for RFID transponders, which can be attached to the objects 7, 7' to be strapped, can be used as the recognition device 20. The reading antenna can of course also comprise multiple components (camera and RFID reading antenna). The recognition device 20 can detect properties of the object to be strapped, based on which the strapping position can be varied.

[0128] For example, a camera as a detection device 20 can detect dimensions or other properties of the object to be strapped that influence 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 strappings can be determined for the object with the corresponding properties. In particular, when using a camera as a detection device 20, areas on the object can also be identified in which no strap loop should be arranged.

[0129] In Fig. 5 shows that the object 7 to be strapped has an address field 21. For example, a barcode containing information about the object 7 to be strapped or containing address information can be arranged in the address field 21. The address information can also be printed as a readable alphanumeric code on the address field 21. The dotted lines in Fig. 5 show the area captured by the camera as the detection 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 conveyor devices 13, 14 of the strapping machine 1 such that the strap loops are not generated on the address field 21.

[0130] The Fig. Figure 7 shows the front view of the strap guide frame 9 and the hold-down device 22 arranged on the strap guide frame 9. The hold-down device 22 is used, for example, when strapping objects 7 such as stacks of newspapers. Before the strap 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. For larger objects 7, particularly packed pallets, a packing press can also be used instead of a hold-down device 22 to press down on the object 7 from above to compress it.

[0131] Fig. Figure 7 also schematically shows the drive motor 23 for the hold-down device 22. This drive motor 23 is also equipped with an angle encoder that 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. Based on the signals from the drive motor 23 for the hold-down device 22, its movement data is 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 to numerically specified target values ​​based on these movement data.

[0132] The movement path of the hold-down device 22 has at least one stop position. Two positions of the hold-down device are Fig. 7. The upper position P0 is the upper stop position of the hold-down device 22. At the start of operation of the strapping machine 1, the hold-down device 22 is moved to the uppermost position P0. Subsequently, during operation of the strapping machine, the current position of the hold-down device 22 is known based on the movement data, namely the signals from the drive motor 23. In this case, the position P0 is the reference position, with reference to which the current position of the hold-down device 22 is determined using the movement data.

[0133] As previously described, the strapping machine 1 can be coupled to detection devices that detect at least one property of the objects transported by 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 that operates with optical or acoustic signals can be provided. Various embodiments of such a height measuring device are known. In particular, the height of the object 7 to be strapped is important for the operation of the strapping machine 1 with the hold-down device 22.

[0134] In the prior art, the hold-down device 22 assumed the uppermost stop position P0 after each strapping process. By detecting the height of the object 7 to be strapped, it is no longer necessary to move the hold-down device 22 to the uppermost position P0. The hold-down device 22 only needs to be arranged a certain distance above the object 7 to be strapped. This safety distance 24 is Fig. 7 is shown hatched and provided with the reference number 24. In position P1, 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 P1. Since it is not necessary to wait until the hold-down device 22 has been moved to position P0 for the object to be strapped to be transported further, the strapping process and in particular the transport process for the object 7 to be strapped can be accelerated considerably. 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.

[0135] The Fig. 8 shows the tape guide frame 9 the other, in Fig. 1, namely two synchronously driven stops 25, 26. The stops 25, 26 are driven by a drive motor 28 and are coupled such that they are at the same distance from the center of the strap guide frame 9 at all times. At the maximum distance D0, the two stops 25, 26 rest against external movement stops. The drive motor 28, in turn, emits rotation angle signals during rotation.

[0136] At the start of operation of the strapping machine 1, the stops 25, 26 are moved to the maximum distance D0 from each other. This position is the reference position of these strapping aids. Alternatively, the contact against a center stop can be used as the reference position, against which the stops 25, 26 rest at a minimum distance. Using the rotation angle signals of the drive motor 28, the control unit 11 of the strapping machine 1 can determine the current position of the stops 25, 26 at any time, starting from the reference position.

[0137] 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 using one of the detection devices already described above. The stops 25, 26 are spaced apart 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 Fig. 8 the distance D1 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 with respect to Fig. 8 towards the viewer. The object 7 to be strapped consequently hits with its Fig. 8 visible front side against the two stops 25, 26. The control unit 11 sets the stops 25, 26 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 to the plane of the stops 25, 26, even if it is slightly tilted. Even if the object 7 to be strapped consists of individual objects such as magazines or the like, the entire front surface of the object 7 to be strapped is aligned to the plane formed by the two stops 25, 26.

[0138] The stops 25, 26 are moved apart when the object 7 to be strapped is transported further. Previously, the stops 25, 26 were moved apart in their initial position by the distance D0. With the present development, it is sufficient to move the stops 25, 26 to a position in which the object 7 to be strapped can easily pass through the stops 25, 26. Fig. 8, this position is reached when the stops 25, 26 are spaced slightly closer than D0. This distance can be redetermined for each package width (width of the object 7 to be strapped). This ensures, on the one hand, that the object 7 to be strapped is safely moved between the stops 25, and, on the other hand, prevents the stops 25, 26 from having to travel unnecessary distances, which consumes unnecessary time.

[0139] For the strapping aids, i.e., the stops 25, 26 and the hold-down device 22, the control unit 11 can monitor the movement data and compare it with target values. If the acceleration or speed of these strapping aids deviates unacceptably from a predetermined target value at any 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 is encountering resistance and that 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 retracted, a warning signal can be sent to a service technician at the same time.

[0140] The Fig. Figure 9 shows a first screen representation 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 that is connected to the strapping machine 1 via a local area network or a wide area network (WAN) such as the Internet. Several icons can be seen on the screen, which indicate various strapping recipes. Icon 101 on the left indicates the run in which no strapping takes place. Icons 102 to 107 indicate six different strapping recipes. Icon 108 activates the programming screens on which the strapping operations can be defined by the strapping machine 1.

[0141] Fig. Figure 10 shows a programming screen on which the strapping positions can be defined numerically. In the top center, a screen display 109 with a package on a conveyor belt can be seen. This screen display shows the overall image with all strapping. Below, three strapping positions are defined in three displays 110 - 112 arranged one below the other. The strapping position shown above is defined 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 specified here, so this distance is zero. The strapping position shown below is defined by a distance from the rear edge of the package, again 100 mm here. Any number of strapping positions can be added. If necessary, the positions must be divided across multiple screen displays.The positions can be entered numerically, e.g. via a keyboard.

[0142] The illustrations to the right of the strapping positions refer to the strap tension. This is represented graphically with a symbol for the standard strap tension. However, it can also be set numerically as a percentage of a predefined standard strap tension.

[0143] Possible resulting strapping patterns are shown in the Fig. 11 to 13. Fig. Figure 11 shows a first single strapping at a distance from the front edge, a second single strapping in the middle, and a third single 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. Figure 12 shows a multiple strapping, here a quadruple strapping, with a specified distance from the front edge and a corresponding multiple strapping with a specified distance from the rear edge. A single strapping is provided as the center strapping. Fig. 13 shows a front strapping with a specified distance from the front edge and a rear strapping with a specified distance from the rear edge. A plurality of equidistant straps are located between them. In this way, depending on the length of the package to be strapped, a multiple strapping can be created with uniform spacing between each two individual straps. The spacing between the equidistant straps can be entered on the input screen or automatically calculated with an optimal value by the control unit 11 based on the measured package length.

[0144] The depictions of the Fig. 11 to 13 can be used to display the object and the strapping to be applied to it on a strapping editor screen. Instead of entering the spacing numerically, the spacing is simply defined by selecting one of the strapping representations with a mouse and then clicking and dragging it onto the object to be strapped.

[0145] The strapping positions defined on the screen are converted into numerical data for determining the loop position on the object and are set by the control unit of the strapping machine 1. The control unit 11 controls the conveyor device 13, 14 for the object 7 to be strapped in such a way that a loop is generated at a position specified on the screen using the strapping editor. Preferably, data sets programmed in this way with target values ​​for the strapping parameters are stored in a data memory connected to the control unit 11. This is shown schematically in Fig. 16. The data storage device 29 can be a data storage device integrated into the control unit 11. Known writable data storage devices such as hard disks and SSDs are suitable for integration into the control unit 11 of the strapping machine 1. However, ROM data storage devices such as CDs can also be provided with the data sets of the target values. For example, if the manufacturer optimizes the machine control system, 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 equipped with a reading unit for such data storage devices.

[0146] 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 strapping parameters specified by the manufacturer or user of the strapping machine 1 are stored. Any combination of internal and external data memories is possible. For each object to be strapped, a data set with target values ​​for the strapping parameters can be selected, which are set by the control unit on the strapping machine 1.The data set includes not only the strapping positions and the strap tensions, it can also include 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.

[0147] The data set can also be fed to the strapping machine 1 in the form of package accompanying data. This package accompanying data can, for example, be stored in an RFID transponder that is attached to the object 7 to be strapped. Alternatively, it can be entered into a printed machine-readable code. This code can be read by a reading device of the strapping machine 1 (e.g., camera, code scanner, receiving antenna for reading RFID transponders).

[0148] Simple identifiers (e.g., via RFID transponders or printed codes) can also be attached to the package, each of which is assigned to the data records. After the identifier has been read, these data records are read from a local data storage device of the strapping machine 1 or via a network from a remote data storage device 29.

[0149] Alternatively, the data set containing the strapping parameters can be selected by recognizing at least one property of the object. Strapping machines are often located in logistics centers where only a limited number of objects are strapped. Each object can be assigned a specific strapping program. The objects are then identified either by specific identifiers that are read out or simply by their height, width, length, weight, or contour. Contour recognition can again be ensured by a camera 20 attached to the strapping machine 1.

[0150] 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.

[0151] The Fig. 14 and Fig. 15 shows an example of the structure of the data records for the target values ​​of the strapping process. First, Fig. 14 shows the strapping pattern, which can include a variety of strapping positions. Secondly, the strap tension is shown in Fig. 14. This can either correspond to the standard strap tension of the strapping machine or be selected based on the height. Any other strap tension selection method, including manual input, is possible.

[0152] For the conveyor devices, i.e., the infeed conveyor 13 and outfeed conveyor 14 of the strapping machine 1, setpoints 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 acceleration and the deceleration during braking), a strapping trigger via a distance of the conveyed distance for 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 more precisely.

[0153] The Fig. 17 shows a front view and the Fig. 18 is a perspective rear view of a sealing unit of a strapping machine according to the development described here. The details are particularly evident in the perspective rear view of the Fig. 18. Here you can see a belt drive 30 and a tensioning drive 31. The belt drive 30 is continuously coupled to a drive roller 32, which is driven by the strapping band 2 (in the Fig. 41-44 not shown). The tensioning drive 31, on the other hand, is pivotally 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.

[0154] Furthermore, a welding device 36 is provided, which welds the ends of a formed band loop. Clamps are provided to the right and left of the welding device 36. These clamps are formed by clamping dies 37, 38 that are pressed against a support plate and clamp the beginning and end of a formed band loop. The welding device 36 welds the band sections located between the clamps 37, 38 together.

[0155] At least the two clamping dies 37, 38 and the welding device 36, but preferably all movable components of the sealing unit 39, are driven by a main shaft 40, also called a king shaft. For this purpose, several cam discs 41 to 46 are arranged on the main shaft 40. The cam disc 41 controls the first clamping die 37. The cam disc 42 controls the second clamping die 38. The cam disc 43 controls the welding device 36. The cam disc 44 controls an upper slide 47, which is displaced to form an abutment for the clamping dies 37 and 38 and the welding device 36 during welding. In the second sliding position, it opens a gap in the strapping machine so that the formed strap loop can exit the sealing unit 39.

[0156] Another cam disc 45 actuates the rocker 34 with the tensioning drive 31, engaging or disengaging it. A cam disc 46 opens and closes the tape guide frame. While the tape is being fed into the tape guide frame, it is closed. To remove the loop formed in the tape guide frame, it is opened.

[0157] According to the present development, the main shaft 40 is controlled to precise angular positions. This is done by means of signals from the drive motor 48 for the main shaft 40. This is Fig. 19 to recognize, in Fig. 18 but not shown for the sake of clarity. As already mentioned above, the drive motor 48 has a rotary encoder that emits at least one signal pulse per degree of rotation of the main shaft 41. Preferably, two signal pulses are emitted per degree of rotation. As particularly shown in the Fig. 19 and Fig. 20, the drive motor 48 is coupled to the main shaft 40 via a reduction gear 49. Consequently, several revolutions of the drive motor 48 are required to cause a single revolution of the main shaft 40.

[0158] Especially in the Fig. 20 shows that a cam disk 50 is mounted on the free end of the motor shaft beyond the reduction gear 49, which interacts with a proximity switch 51. Five positions are marked along the circumference of the cam disk 50 with the numbers 0, 1, 2, 3, and 4, each of which is assigned to a cam 52-55 on the circumference of the cam disk 50. The proximity switch 51 sends a signal to the control unit 11 of the strapping machine 1 when the cam disk 50 is in a position where one of the cams 52-55 is close to 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 for the angular position with the main shaft 40.The different angular positions to which main shaft 40 can be rotated during each strapping cycle are described above. The cam discs 41-46 move each component controlled by main shaft 40 to the angular positions marked by one of the cams 52-55, respectively, into a position that corresponds to the corresponding operating state of strapping machine 1. For this reason, the marked angular position should be controlled as precisely as possible.

[0159] 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, each of which corresponds 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 to detect 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 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.

[0160] Due to the reduction of the reduction gear 49, the drive motor 48 sends over 700 signal pulses, each representing a rotation of the main shaft 40 by a specific angular segment, to the control unit 11 on the strapping machine 1 for each revolution of the main shaft 40. This means that the control unit 11 of the strapping machine 1 can resolve the rotational position of the main shaft 40 with an accuracy of 0.5°.

[0161] Of course, the Fig.20, the five cams 52-55 shown are arranged on the circumference of the cam disk 50. However, for reliable operation of the strapping machine 1 with 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 therefore set the optimal rotational angle of the main shaft 40 in each case. If deviations from the actually achieved rotational position of the main shaft 40 are detected based on the signals from the drive motor 48, these can be corrected immediately during the next drive operation, so that, for example, the braking of the main shaft 40 can be initiated earlier by deactivating the drive motor 48, or can be initiated later so that the next approached angular position of the main shaft 40 corresponds exactly to the target value.From a first angular position, for example, for the welding process, to the next, identical angular position in the subsequent strapping cycle, the actual value achieved in the previous strapping cycle can also be taken into account in order to vary the control of the drive motor 48 by the control unit 11. If, for example, the actual value in the closing position is greater than the target value, braking can be initiated earlier the next time this position is approached. If the target value is lower, braking can be initiated later.

[0162] Key aspects of the development described here are listed again below, sorted by number. Recording the strapping position 1. A method for strapping objects, comprising the following steps: • Transporting an object (7, 7') by means of at least one conveyor device (13, 14) to a strapping station, • Forming at least one loop of a strapping band (2) around the object (7, 7') by means of a strapping device, • Connecting the ends of the loop together, wherein at least one position detecting means (17, 18, 19) detects the position of the object (7, 7'), characterized by the following steps: • a detection device detects the conveying direction and conveying distance of the conveying device (13,14), • the signals of the detection device and the position detection means (17, 18, 19) are transmitted to a control unit (20), • the control unit (20) controls the conveyor device (13, 14) on the basis of the transmitted signals in such a way that the object (7, 7') is transported into at least one strapping position in which the loop of strapping band (2) is formed on the object (7, 7') at a predetermined loop position. 2. Method according to number 1, characterized in that the position detection means (17, 18, 19) detects the position of the front edge of the object (7, 7') and the loop position is stored in the control unit (20) as a predetermined distance from the front edge. 3. Method according to number 2, characterized in that a first position detection means (17) detects the position of the front edge of the object (7, 7') at a great distance from the strapping station and that a second position detection means (18) detects the position of the front edge of the object (7, 7') near the strapping station and that the value of the detected conveying distance is checked and, if necessary, corrected by the value of the position of the front edge of the object (7, 7') detected by the second position detection means (18). 4. Method according to one of the preceding numbers, characterized in that the position detection means (17, 18, 19) detects the position of the rear edge of the object (7, 7') and the loop position is stored in the control unit (20) as a predetermined distance from the rear edge. 5. Method according to one of the preceding numbers, characterized in that the position detection means (17, 18, 19) detects the position of the front edge and the rear edge of the object (7, 7') and the loop position is specified in the control unit (20) as the center between the front edge and the rear edge. 6. Method according to one of the preceding numbers, characterized in that the object (7, 7') is first transported by the conveyor device (13, 14) to the position detection means (17, 18, 19) until the front edge is detected, then transported further until the rear edge is detected and the length of the object (7, 7') is determined from the conveyor path, then transported to the strapping position. 7. Method according to one of the preceding numbers, characterized in that the object (7, 7') is transported into several strapping positions, in each of which a loop is formed on the object. 8. Method according to number 7, characterized in that the object (7, 7') is transported to a first strapping position and provided with a loop which has a predetermined distance from the front edge, and in that the object (7, 7') is transported at least once to a next strapping position and provided with a loop which has a predetermined distance from the preceding loop. 9. Method according to one of the preceding numbers, characterized in that at least one property of the object (7, 7') is recognized by a recognition device (20), that data which specify the property of the object (7, 7') are forwarded to the control unit (20), and that the control unit (20) determines at least one target value for the loop position from the data specifying the property of the object (7, 7'). 10. Method according to one of the preceding numbers, characterized in that the positive and / or negative acceleration of the conveyor device (13, 14) can be numerically adjusted by the control unit (20) to a value which is optimal for the respective strapping process. 11. Strapping system for strapping objects, having the following features: • at least one conveyor device (13, 14) for transporting an object (7, 7') to a strapping station, • at least one strapping device for forming a loop from a strapping band (2) around the object (7, 7'), • at least one connecting device for connecting the ends of the loop to each other, • at least one position detection means (17, 18, 19) for detecting the position of the object (7, 7'), characterized by the following features: • a detection device for detecting the conveying direction and conveying distance of the conveying device (13, 14), • a control unit (20) to which the signals of the detection device and the position detection means (17, 18, 19) are transmitted, wherein the control unit (20) is configured to control the conveying device (13, 14) on the basis of the transmitted signals in such a way that the object (7, 7') is transported into at least one strapping position in which the loop of strapping band (2) is formed at a predetermined loop position on the object (7, 7'). 12. Strapping system according to number 11, characterized in that a first position detection means (17, 18, 19) is arranged at a great distance from the strapping station and that a second position detection means (17, 18, 19) is arranged close to the strapping station, wherein the value of the detected conveying distance is checked and, if necessary, corrected by the value of the position of the front edge of the object (7, 7') detected by the second position detection means (17, 18, 19). 13. Strapping system according to number 11 or 12, characterized in that the position detection means (17, 18, 19) is selected from: • a light barrier arranged above the conveyor device (13, 14), consisting of a light source and a light sensor; • a light barrier strip arranged above the conveyor device (13, 14), consisting of a plurality of spaced-apart light sources on a first side of the conveyor device (13, 14) and a plurality of correspondingly spaced-apart light sensors on a second side of the conveyor device (13, 14) opposite the first side; • a camera (20) recording the area above the conveyor device (13,14). 14. Strapping system according to one of numbers 11 to 13, characterized in that the detection device for detecting the conveying direction and conveying distance of the conveying device (13, 14) is selected from: • at least one rotary angle sensor which emits electrical signals when a motor shaft of a drive motor (57, 58) of the conveyor device (13, 14) rotates; • an increment disk, the rotary movement of which is coupled to the rotary movement of a shaft of a drive motor of the conveyor device (13, 14) and an increment sensor which generates signals generated by the movement of the increment disk, wherein the increment disk preferably has alternating transparent and opaque sectors and the increment sensor is a light barrier. 15. Strapping system according to one of numbers 11 to 14, characterized in that it comprises a recognition device (20) which is designed to recognize at least one property of the object (7, 7') and to forward data which specify the property of the object (7, 7') to the control unit (20), and in that the control unit (20) is designed to determine at least one target value for the loop position from the data which specify the property of the object (7, 7'). 16. Strapping system according to number 15, characterized in that the detection device (20) is selected from: • a scanner for scanning a machine-readable code attached to the object (7,7'); • a reading antenna for reading an RFID transponder attached to the object (7,7'); • a camera (20) for recording the optical features of the object (7,7'). Motion detection for strapping aids (e.g. stop, hold-down device, packing press) 17. A method for strapping objects, comprising the following steps: • Transporting an object (7, 7') by means of a conveyor device (13, 14) to a strapping station, • Forming at least one loop of a strapping band (2) around the object (7, 7') by means of a strapping device, • Connecting the ends of the loop together, • Actuating at least one drive device for at least one strapping aid before or during the strapping process; characterized by the following steps: • a movement detection unit continuously records the movement data of the strapping aid (22, 25, 26), • the movement data are transmitted to a control unit (20), • the control unit (20) controls the drive device for the strapping aid (22, 25, 26) by means of the movement data based on numerically specified target values. 18. Method according to number 17, characterized in that the strapping aid (22, 25, 26) is moved by the drive device into a reference position and the movement detection unit detects the movement data of the strapping aid (22, 25, 26) with respect to this reference position. 19. Method according to number 17 or 18, characterized in that at least one of the following strapping aids (22, 25, 26) is controlled by means of the movement detection unit: • an attack; • a hold-down device; • a packing press. 20. Method according to number 17, 18 or 19, characterized in that a detection device (20) detects at least one property of the object (7, 7') transported by means of the conveyor device (13, 14) and the drive device of the strapping aid (22, 25, 26) controls the setpoint values ​​for controlling the drive device as a function of the detected property. 21. Method according to one of numbers 17 to 20, characterized in that the control unit (20) controls the drive device for the strapping aid (22, 25, 26) in such a way that the strapping aid (22, 25, 26) is moved back to a starting position after the strapping process only so far that a free further transport of the object (7, 7') is possible. 22. Method according to one of numbers 17 to 21, characterized in that the control unit (20) switches off the drive device or actuates it in the opposite direction in the event of an inadmissible deviation of the detected movement data from a target value. 23. Strapping system for strapping objects, having the following features: • at least one conveyor device (13, 14) for transporting an object (7, 7') to a strapping station, • at least one strapping device for forming a loop from a strapping band (2) around the object (7, 7'), • at least one connecting device for connecting the ends of the loop to each other, • at least one drive device for driving at least one strapping aid (22, 25, 26) before or during the strapping process, characterized in that a movement detection unit continuously detects the movement data of the strapping aid (22, 25, 26) and transmits them to a control unit (20), wherein the control unit (20) controls the drive device on the basis of numerical target values ​​by means of the movement data. 24. Strapping system according to point 23, characterized in that the strapping aid is selected from the following: • Stop (25,26); • Hold-down device (22); • Packing press. 25. Strapping system according to number 23 or 24, characterized in that it has a detection device (20) which detects at least one property of the object (7, 7') transported by means of the conveyor device (13, 14), wherein the target values ​​for controlling the drive device of the strapping aid (22, 25, 26) are determined as a function of the detected property. 26. Strapping system according to number 25, characterized in that the control unit (20) controls the drive device for the strapping aid (22, 25, 26) in such a way that the strapping aid (22, 25, 26), depending on the detected property of the object (7, 7') to be strapped, is moved after the strapping process only far enough out of the transport path of the object (7, 7') to be strapped that a free further transport of the object (7, 7') is possible. 27. Strapping system according to one of numbers 23 to 25, characterized in that the control unit (20) is designed to switch off the drive device in the event of an inadmissible deviation of the detected movement data from a target value or to actuate it in the opposite direction. Strapping position editor 28. A method for strapping objects, comprising the following steps: • Transporting an object (7, 7') by means of a conveyor device (13, 14) to a strapping station, • Forming at least one loop of a strapping band (2) around the object (7, 7') by means of a strapping device, • Connecting the ends of the loop together, characterized by the following steps: • Displaying a representation of the object (7,7') on a display device; • Marking at least one desired strapping position on the representation of the object (7,7') by manual input; • Conversion of the marked strapping position into numerical data to determine the loop position on the object (7,7'), • Transmission of the numerical data of the loop position to a control unit (20) for positioning the object (7,7'); • the control unit (20) controls the conveyor device (13, 14) on the basis of the transmitted data in such a way that the object (7, 7') is transported into at least one strapping position in which the loop of strapping band (2) is formed at a predetermined loop position on the object (7, 7'). 29. Method according to number 28, characterized in that at least one strapping aid (22, 25, 26) is further displayed on the display device and that by means of manual input at least one position of the strapping aid (22, 25, 26) is marked in the displayed representation, converted into position data and transmitted to the control unit (20). 30. Method according to point 28 or 29, characterized in that the at least one position marking is applied using one of the following manual input means: • Mouse; • Touch screen; • Trackball. Data sets with target values ​​for strapping parameters 31. A method for strapping objects, comprising the following steps: • Transporting an object (7, 7') by means of a conveyor device (13, 14) to a strapping station, • Forming at least one loop of a strapping band (2) around the object (7, 7') by means of a strapping device, • Connecting the ends of the loop together, • Control of strapping parameters, which include at least the strapping position, by means of a control unit (20), characterized by the following steps: • Storing data sets with target values ​​for the strapping parameters in a data memory (29) which is connected to the control unit (20); • Selection of a data set with target values ​​for the strapping parameters by the control unit (20) for each strapping process. 32. Method according to number 31, characterized in that a data set with target values ​​for the strapping parameters is transmitted to the control unit (20) as package accompanying data and is used during the strapping process to select a data set with target values ​​for the strapping parameters. 33. Method according to number 32, characterized in that the data record is stored in a machine-readable data storage device (29) attached to the package, in particular an RFID transponder, or a printed machine-readable code, and is read out by a reading device connected to the control unit (20) before the start of the strapping process. 34. Procedure according to point 31, characterised by the following steps: • Recognizing at least one property of the object (7,7') by a recognition device (20) and transmitting the data specifying the property of the object (7,7') to the control unit (20); • Selection of a data set with target values ​​based on the data specifying the at least one property of the object (7,7') by the control unit (20). 35. Method according to point 34, characterized in that at least one of the following properties is detected: • Height of the object (7.7'); • Width of the object (7.7'); • Length of the object (7.7'); • Weight of the object (7.7'); • Strength of the object (7.7'); • Contour of the object (7,7'); • Color of the object (7.7'). 36. Method according to one of numbers 31 to 35, characterized in that the data set comprises target 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 from the strapping position to the rear edge of the object (7.7'); • Number of strappings; • Band tension of the strapping band (2); • Position of a stop during the strapping process; • Position of the stop during transport of the object (7,7'); • Position of a hold-down device or a packing press during transport of the object (7,7'); • Pressure force of the hold-down device or the packing press during the strapping process. 37. Method according to one of numbers 34 to 36, characterized in that the at least one property of the object (7, 7') is recognized by at least one of the following recognition devices (20): • Light barrier; • Light barrier strip, consisting of several spaced-apart light sources on a first side of the conveyor and several correspondingly spaced-apart light sensors on a second side of the conveyor opposite the first side; • Reading device for printed code; • Reading antenna for RFID transponders; • Camera (20). 38. Strapping system for strapping objects, having the following features: • at least one conveyor device (13, 14) for transporting an object (7, 7') to a strapping station, • at least one strapping device for forming a loop from a strapping band (2) around the object (7, 7'), • at least one connecting device for connecting the ends of the loop to each other, • a control unit (20) for controlling a plurality of strapping parameters, including strapping position and tension of the strapping band (2) applied around the object (7,7'). characterized by a data memory (29) which is connected to the control unit (20) and supplies the control unit (20) with data sets containing target values ​​for the strapping parameters. 39. Strapping system according to number 38, characterized by at least one recognition device (20) for recognizing 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 (20), wherein the data are used to select a data set with target values ​​for the strapping parameters on the basis of the at least one property of the object (7, 7'). 40. Strapping system according to point 39, characterized in that the at least one detection device (20) is designed to detect 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'); • Weight of the object (7.7'); • Strength of the object (7.7'); • Contour of the object (7,7'); • Color of the object (7.7'). 41. Strapping system according to one of numbers 38 to 40, characterized in that the control unit (20) is designed 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 from the strapping position to the rear edge of the object (7.7'); • Number of strappings; • Band tension of the strapping band (2); • Deceleration and acceleration of the conveyor device (13,14); • Position of a stop during the strapping process; • Position of the stop during transport of the object (7,7'); • Position of a hold-down device or a packing press during transport of the object (7,7'); • Pressure force of the hold-down device or the packing press during the strapping process. 42. Strapping system according to one of the preceding numbers 39 to 41, characterized in that it comprises at least one of the following detection devices (20): • Light barrier; • Light barrier strip, consisting of several spaced-apart light sources on a first side of the conveyor and several correspondingly spaced-apart light sensors on a second side of the conveyor opposite the first side; • Reading device for printed code; • Reading antenna for RFID transponders; • Camera (20). Control of the main shaft of the closure unit 43. A method for strapping at least one object (7, 7') with a strapping loop on a strapping machine (1) with a closing unit which has at least a first clamp (37) for the front end of the strapping loop, a second clamp (38) for the rear end of the strapping loop and a welding device (36), wherein at least one strapping loop is formed from a strapping band (2) around the object (7, 7'), tensioned and closed by the closing unit, wherein a main shaft (40) moves at least the clamps (37, 38) and the welding device (36) via cam discs (41-46) and is rotated into at least one predetermined angular position by a drive motor (48) during the closing process, characterized by the following steps: • a detection device detects the angle of rotation of the main shaft (40), • the signals of the detection device are transmitted to a control unit (20), • the control unit (20) compares a target value for the angular position with the actual value of the angular position determined from the transmitted signals; • the control unit (20) changes the control of the drive motor in the event of deviations between the target value and the angle of rotation detected by the detection device. 44. Method according to point 43, characterized in that the main shaft (40) moves at least one of the following components: • the clamps (37,38) of the closure unit are moved from an open position to a clamped position; • the welding device (36) is moved from an inactive position to a welding position; • at least one drive (31) for the belt is moved from an engaged position to a disengaged position, • an upper slide (47) of the locking unit is moved from a closed position to an open position. 45. Method according to point 43 or 44, characterized in that the main shaft (40) is rotated into at least one of the following angular positions: • Position for retracting the excess tape material; • Position for tensioning the belt material; • Welding position; • Position for cooling the welding point; • Opening position; • Zero position. 46. ​​Method according to one of numbers 43 to 45, characterized in that the detection device is formed by a rotary angle sensor of the drive motor (48), which emits electrical signals when a motor shaft of the drive motor (48) rotates. 47. Method according to one of numbers 43 to 46, characterized in that a reference position marker is connected to the main shaft (40), which cooperates with a sensor, the signal of which is passed to the control unit (20). 48. Strapping machine (1) with a closing unit which has at least a first clamp (37) for the front end of the strap loop, a second clamp (38) for the rear end of the strap loop and a welding device (36), wherein a main shaft (40) moves at least the clamps (37, 38) and the welding device (36) via cam discs (41-46) and is rotated into at least one predetermined angular position by a drive motor (48) during the closing process, characterized by: • a detection device that detects the angle of rotation of the main shaft (40), • a signal line (56) via which the signals of the detection device are transmitted to a control unit (20) for the drive motor (48), • a data memory (29) associated with the control unit (20), in which at least one target value for the angular position is stored, wherein the control unit (20) changes the control of the drive motor in the event of deviations between the target value and the angle of rotation detected by the detection device. 49. Strapping machine (1) according to number 48, characterized in that the clamps (37, 38) of the sealing unit can be moved from an open position to a clamping position and / or the welding device (36) can be moved from an inactive position to a welding position by the main shaft (40). 50. Strapping machine (1) according to one of numbers 48 or 49, characterized in that the detection device is a rotary angle sensor of the drive motor (48) which emits electrical signals when a motor shaft of the drive motor (48) rotates. 51. Strapping machine (1) according to one of numbers 48 to 50, characterized in that a reference position marker is connected to the main shaft (40), which cooperates with a sensor, the signal of which is passed to the control unit (20). 52. Strapping machine (1) according to one of the numbers 48 to 50, characterized in that the welding device is selected from: • a fusion welding device with heating element; • an ultrasonic welding device • a friction welding device. List of reference symbols 1 strapping machine 2 volumes 3 circuit boards 4 retraction device 5 tape magazine 6 Belt conveyor device 7.7' object 8 clamping device 9 Tape guide frame 10 locking unit 11 Control unit 12 socket part 13 Infeed conveyor, first conveyor device 14 Outlet conveyor, second conveyor device 15 input-side accumulation conveyor 16 output-side accumulation conveyors 17 Position detection device, light barrier 18 Position detection device, light barrier 19 Position detection device, light barrier 20 Camera, detection device 21 Address field 22 hold-down clamps, strapping aids 23 Drive motor for the hold-down device 24 Safety distance 25 left stop, strapping aid 26 right stop, strapping aid 28 Drive motor for the stops 29 data storage 30 belt drive 31 Tension drive 32 drive roller 33 Tension pulley 34 Seesaw 35 tension pulley 36 Welding device 37 clamp, clamping stamp 38 clamp, clamping stamp 39 locking unit 40 Main shaft, vertical shaft 41 Cam disc for first clamping punch 42 Cam disc for second clamping stamp 43 Cam disc for welding device 44 Cam disc for top slide 45 Cam disc for tensioning drive 46 Cam disc for belt guide frame 47 upper slide 48 Drive motor for the main shaft 49 reduction gears 50 cam disc 51 proximity switches 52-55 cams 56 Signal line 57 Drive motor for infeed conveyor 58 Drive motor for discharge conveyor 101 Run 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

[1] Method for strapping objects, comprising the following steps: • Transporting an object (7, 7') by means of at least one conveyor device (13, 14) to a strapping station, • Forming at least one loop of a strapping band (2) around the object (7, 7') by means of a strapping device, • Connecting the ends of the loop together, • Detecting the position of the object (7, 7') by at least one position detecting means (17, 18, 19), • a detection device detects the conveying direction and conveying distance of the conveying device (13,14), • the signals of the detection device and the position detection means (17, 18, 19) are transmitted to a control unit (11), • the control unit (11) controls the conveyor device (13, 14) on the basis of the transmitted signals in such a way that the object (7, 7') is transported into at least one strapping position in which the loop of strapping band (2) is formed on the object (7, 7') at a predetermined loop position, • at least one property of the object (7, 7') is recognized by a recognition device (20), • Data specifying the property of the object (7, 7') are forwarded to the control unit (11) and • the control unit (11) determines at least one target value for the loop position from the data specifying the property of the object (7, 7'), characterized by following steps: • Storing data sets with target values ​​for the strapping parameters in a data memory (29) which is connected to the control unit (11); • Selection of a data set with target values ​​for the strapping parameters by the control unit (11) for each strapping process, wherein the data set is selected by the control unit (11) on the basis of the data specifying the at least one property of the object (7, 7'). [2] Method according to claim 1, characterized by that the position detection means (17, 18, 19) detects the position of the front edge of the object (7, 7') and the loop position is stored in the control unit (11) as a predetermined distance from the front edge. [3] Method according to claim 2, characterized bythat a first position detection means (17) detects the position of the front edge of the object (7,7') at a great distance from the strapping station and that a second position detection means (18) detects the position of the front edge of the object (7,7') near the strapping station and that the value of the detected conveying distance is checked and, if necessary, corrected by the value of the position of the front edge of the object (7,7') detected by the second position detection means (18). [4] Method according to one of the preceding claims, characterized by that the position detection means (17, 18, 19) detects the position of the rear edge of the object (7, 7') and the loop position is stored in the control unit (11) as a predetermined distance from the rear edge. [5] Method according to one of the preceding claims, characterized bythat the position detection means (17, 18, 19) detects the position of the front edge and the rear edge of the object (7, 7') and the loop position is specified in the control unit (11) as the center between the front edge and the rear edge. [6] Method according to one of the preceding claims, characterized by that the object (7,7') is first transported by the conveyor device (13,14) to the position detection means (17,18,19) until the front edge is detected, then transported further until the rear edge is detected and the length of the object (7,7') is determined from the conveyor path, then transported to the strapping position. [7] Method according to one of the preceding claims, characterized by that the object (7,7') is transported into several strapping positions, in each of which a loop is formed on the object. [8] Method according to claim 7, characterized bythat the object (7,7') is transported to a first strapping position and provided with a loop which has a predetermined distance from the front edge, and that the object (7,7') is transported at least once to a next strapping position and provided with a loop which has a predetermined distance from the preceding loop. [9] Method according to one of the preceding claims, characterized by that the positive and / or negative acceleration of the conveyor device (13, 14) can be numerically adjusted by the control unit (11) to an optimal value for the respective strapping process. [10] Strapping system for strapping objects according to a method according to one of the preceding claims, having the following features: • at least one conveyor device (13, 14) for transporting an object (7, 7') to a strapping station, • at least one strapping device for forming a loop from a strapping band (2) around the object (7, 7'), • at least one connecting device for connecting the ends of the loop to each other, • at least one position detection means (17, 18, 19) for detecting the position of the object (7, 7'), • a detection device for detecting the conveying direction and conveying distance of the conveying device (13, 14), • a control unit (11) to which the signals of the detection device and the position detection means (17, 18, 19) are transmitted, wherein the control unit (11) is configured to control the conveying device (13, 14) on the basis of the transmitted signals in such a way that the object (7, 7') is transported into at least one strapping position in which the loop of strapping band (2) is formed at a predetermined loop position on the object (7, 7'), wherein it comprises a recognition device (20) which is configured to recognize at least one property of the object (7, 7') and to forward data specifying the property of the object (7, 7') to the control unit (11), and wherein the control unit (11) is configured to determine at least one target value for the loop position from the data specifying the property of the object (7, 7'), and wherein it comprises a data memory (29) which is connected to the control unit (11) and supplies the control unit (11) with data sets containing target values ​​for the strapping parameters. [11] Strapping system according to claim 10, characterized bythat a first position detection means (17, 18, 19) is arranged at a great distance from the strapping station and that a second position detection means (17, 18, 19) is arranged close to the strapping station, wherein the value of the detected conveying distance is checked and, if necessary, corrected by the value of the position of the front edge of the object (7, 7') detected by the second position detection means (17, 18, 19). [12] Strapping system according to claim 10 or 11, characterized by that the position detection means (17,18,19) is selected from: • a light barrier arranged above the conveyor device (13, 14), consisting of a light source and a light sensor; • a light barrier strip arranged above the conveyor device (13, 14), consisting of a plurality of spaced-apart light sources on a first side of the conveyor device (13, 14) and a plurality of correspondingly spaced-apart light sensors on a second side of the conveyor device (13, 14) opposite the first side; • a camera (20) recording the area above the conveyor device (13,14). [13] Strapping system according to one of claims 10 to 12, characterized by that the detection device for detecting the conveying direction and conveying distance of the conveying device (13,14) is selected from: • at least one rotary angle sensor which emits electrical signals when a motor shaft of a drive motor (57, 58) of the conveyor device (13, 14) rotates; • an increment disk, the rotary movement of which is coupled to the rotary movement of a shaft of a drive motor of the conveyor device (13, 14) and an increment sensor which generates signals generated by the movement of the increment disk, wherein the increment disk preferably has alternating transparent and opaque sectors and the increment sensor is a light barrier. [14] Strapping system according to one of claims 10 to 13, characterized by that the detection device (20) is selected from: • a scanner for scanning a machine-readable code attached to the object (7,7'); • a reading antenna for reading an RFID transponder attached to the object (7,7'); • a camera (20) for recording the optical features of the object (7,7').

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