Strapping device

Abstract

A strapping device (100) is described, comprising a tensioning apparatus (1) with a tensioning wheel (11) for tensioning a strap (S) around one or more articles, a joining apparatus (2) with a joining jaw (21) for joining two overlapping portions (Sl, Su) of the strap, a first actuating device (14) comprising a first motor (141) and operatively connected to the tensioning apparatus, a second actuating device (24) comprising a second motor (241) and operatively connected to the joining apparatus, wherein the first actuating device is, driven by the first motor, configured to lower and raise the tensioning wheel between an open position and an active position with respect to a tensioning base (12), and the second actuating device is, driven by the second motor, configured to lower and raise the joining jaw between an open position and an active position with respect to a joining base (22).

Description

Field of the invention

[0001] The present invention relates to a strapping device for strapping one or more articles with a strap.Background of the invention

[0002] Strapping devices are used for packing various articles by placing a strap around the articles such that two portions of the strap overlap each other by forming a loop around the articles. The overlapping portions of the strap are connected to each other by a strapping device which is applied to tension the strap and to join the overlapping portions of the strap. For tensioning the strap, a tensioning apparatus with a tensioning wheel is used which can be lowered onto the strap in order to contact the strap for tensioning and raised from the strap in order to release or to introduce the strap. Various joining techniques can be used for joining the overlapping portion, such as for example welding, crimping, gluing etc., the specific technique depending on the articles to be strapped and / or the material of the strap. For joining the overlapping portions of the strap, a welding crimper can be lowered onto the strap in order to join the overlapping portions of the strap and raised from the strap in order to release or to introduce the strap.

[0003] For example, DE 10 2011 122 157 A1 describes a strapping apparatus for strapping a tensioning strap around a packaged item, said apparatus including a frictional wheel which works against a support for tightening the named tensioning strap, wherein the frictional wheel is operatively connected to a drive and is liftable from the support by means of a pivot lever. The pivot lever arm is provided with an interrupting element in order to interrupt the path of action between the frictional wheel and the drive. A gear unit is provided in the path of action between the frictional wheel and the drive and the interrupting element acts on an element of said gear unit. The gear unit is arranged in or on a bearing block, the bearing block being tiltable by means of the pivot lever. As a result of the tilting of the bearing block, the gear unit can be tilted simultaneously in this case and the frictional wheel which is connected thereto can also be lifted off at the same time. An elastic means, for example a spring or a helical spring, is arranged between the pivot lever and the bearing block. The elastic means has the effect of pivoting the pivot lever back automatically in the case of its non-actuation.Summary of the invention

[0004] While packing articles, it is desired to provide a strapping device where the tensioning apparatus and the joining apparatus can be operated in a precise and an efficient manner.

[0005] It is therefore an object of the invention to provide a strapping device which at least partially improves the prior art and avoids at least part of the disadvantages of the prior art.

[0006] According to the present invention, this object is achieved by the features of the independent claims. In addition, further advantageous embodiments follow from the dependent claims and the description as well as the figures.

[0007] According to an aspect of the invention, this object is particularly achieved by a strapping device for strapping one or more articles with a strap, comprising a tensioning apparatus with a tensioning wheel for tensioning the strap around the one or more articles, a joining apparatus with a joining jaw for joining two overlapping portions of the strap, a first actuating device comprising a first motor and operatively connected to the tensioning apparatus, a second actuating device comprising a second motor and operatively connected to the joining apparatus, wherein the first actuating device is, driven by the first motor, configured to actuate the tensioning apparatus such that the tensioning wheel is lowerable from an open position to an active position towards a tensioning base for contacting the strap and raisable from the active position to the open position away from the tensioning base, and the second actuating device is, driven by the second motor, configured to actuate the joining apparatus such that the joining jaw is lowerable from an open position to an active position towards a joining base for contacting a portion of the strap overlapping another portion of the strap and raisable from the active position to the open position away from the joining base.

[0008] By providing a first actuating device with a first motor and a second actuating device with a second motor, the tensioning apparatus and the joining apparatus can separately and independently be actuated and respectively be controlled. Independent actuation of the tensioning apparatus and the joining apparatus allows to increase the flexibility in operating the strapping device. For example, the tensioning apparatus and the joining apparatus may independently and simultaneously be addressed such that the actuating motions of the tensioning wheel and the joining jaw may at least partially overlap in time. Furthermore, the first actuating device and second actuating device and the respective first motor and second motor may better be adapted to the requirements of the tensioning apparatus and the joining apparatus, respectively.

[0009] Compared to known solutions where a shared actuating device with a single motor is used for actuating the tensioning apparatus and the joining apparatus, the structure of the strapping device can be simplified. In particular, complex gearing and / or coupling and / or freewheel structures for transmitting the motion of the single motor to the tensioning apparatus and the joining apparatus may be dispensed with since the tensioning apparatus and the joining apparatus each have a dedicated actuating device with a separate motor for actuation. Furthermore, the switch-on times for each motor of the first and second actuating devices may be reduced compared to a single motor actuating both the tensioning apparatus and the joining apparatus. By reducing the switch-on time, heating of the motor can be reduced, improving the efficiency and life span of the motor. Besides that, the life span of the first and second motors may be increased due to each of the first and second motor only running half of the cycles compared to a single motor driving the tensioning and the joining apparatus.

[0010] Preferably, the motors are electric motors. The joining apparatus may be a friction welder. The strapping device may be a portable strapping device or a strapping head of a strapping machine. The portable strapping device may be battery-powered.

[0011] In some embodiments, the first actuating device is configured to vary the speed of actuating the tensioning apparatus depending on the position of the tensioning wheel with respect to the tensioning base.

[0012] Therefore, lowering and / or raising the tensioning wheel with respect to the tensioning base can be accelerated and / or decelerated depending on the position of the tensioning wheel. The first actuating device with the first motor therefore provides the possibility of deploying elaborate actuation schemes in a rather simple fashion.

[0013] In particular, raising of the tensioning apparatus can be executed in a controlled fashion due to the continuous operative connection of the first actuating device to the tensioning apparatus. Risk of damage of components involved due to e.g. sudden movement, such as a free stroke, of a component can thereby be reduced.

[0014] In some embodiments, the strapping device comprises an operating drive configured to drive the tensioning wheel for tensioning the strap in the active position of the tensioning apparatus and / or the joining jaw for joining two overlapping portions of the strap in the active position of the joining apparatus.

[0015] The strapping device may comprise a first operating drive for driving the tensioning wheel and a second operating drive for driving the joining jaw. Alternatively, the strapping device may comprise a shared operating drive configured to drive the tensioning wheel and the joining jaw. The operating drive may drive the tensioning wheel and / or the joining jaw not only in its respective active position. For example, the operating drive may start driving the tensioning wheel and / or the joining jaw before reaching its respective active position.

[0016] In some embodiments, the joining jaw is movable between the open position and the active position while the operating drive drives the tensioning wheel.

[0017] In particular, the joining jaw can pretravel a part of the distance between the open position and the active position while the tensioning wheel is being held in its active position by the first actuating device. After tensioning, the joining jaw can travel the remaining distance in order to reach its active position for executing the joining of the overlapping portions of the strap. The possibility of pre-moving the joining jaw between from the open position towards the active position while the tensioning wheel is held in its active position advantageously allows to increase the distance between the joining jaw and the joining base in the open position, since the joining jaw can then reach its active position by travelling the remaining distance after tensioning. Increasing the distance between the joining jaw and the joining base in the open position provides the advantage that the insertion of a strap can be facilitated.

[0018] In some embodiments, the joining jaw is movable between the open position and the active position while the operating drive drives the joining jaw.

[0019] The joining jaw can therefore already be driven before the joining jaw reaches the active position and contacts the strap. By driving the joining jaw before contacting the strap, the mechanical load can be reduced since the joining jaw and the overlapping strap portions do not have to be accelerated simultaneously. For an embodiment of the joining apparatus being a friction welder, for example, detrimental effects such as blocking of the operating drive can be reduced or avoided if the joining jaw is already driven when contacting the strap. In particular, the joining jaw can be driven before the full normal force required for welding is applied onto the overlapping portions of the strap.

[0020] Furthermore, the driving of the operating drive may be controlled to be initiated at a predetermined position of the joining jaw between the open position and the active position. By controlling the position where the driving of the operating drive is initiated, it can be prevented that the joining jaw moves at a too high joining velocity when coming into contact with the strap.

[0021] In some embodiments, the second actuating device is configured to vary the speed of actuating the joining apparatus depending on the position of the joining jaw with respect to the joining base.

[0022] Lowering and / or raising the joining jaw with respect to the joining base can therefore be accelerated and / or decelerated depending on the position of the joining jaw, thereby providing the possibility of deploying elaborate actuation schemes for the joining apparatus in a rather simple fashion.

[0023] In particular, raising of the joining apparatus can be executed in a controlled fashion due to the continuous operative connection of the second actuating device to the joining apparatus. Risk of damage of components involved due to e.g. sudden movement, such as a free stroke, of a component can thereby be reduced.

[0024] In some embodiments, the first actuating device comprises a first transmission configured to convert a rotatory motion of the first motor to a linear motion for raising and / or lowering the tensioning wheel with respect to the tensioning base.

[0025] Since the first actuating device can be dedicated for actuating the tensioning apparatus, the structure of the first transmission can be simplified to the conversion of the motor motion to an actuating motion for the tensioning wheel, without the need of a complex mechanism for diverting the motor motion to the joining apparatus. Furthermore, the rotary motion of the first motor can be reversed for lowering and raising the tensioning wheel, if needed, since the use of freewheels can be avoided.

[0026] In some embodiments, the first transmission comprises a first eccentric shaft drivable by the first motor, wherein the first eccentric shaft is operatively connected to the tensioning apparatus and configured to raise and / or lower the tensioning wheel with respect to the tensioning base.

[0027] Using the first eccentric shaft, the tensioning wheel can therefore be lowered and raised with respect to the tensioning base.

[0028] In some embodiments, the first transmission comprises a first actuation rod which is connected at a first end to the first eccentric shaft and at a second end to a pivotable rocker, wherein the tensioning wheel is rotatably mounted on the rocker.

[0029] The rocker is preferably pivotable about a pivot axis which is oriented parallel to the axis of the first eccentric shaft. Alternatively, the pivot axis may be perpendicularly oriented to the axis of the first eccentric shaft. The first actuation rod may therefore be lowered and raised by the first eccentric shaft being driven by the first motor and thereby lower and raise the rocker due to the connection of the second end of the first actuation rod to the rocker. Preferably, the second end of the first actuation rod is connected to an actuation portion of the rocker which is oppositely arranged to the pivot axis of the rocker with respect to the tensioning wheel.

[0030] In some embodiments, a first compression spring is arranged between the first eccentric shaft and the rocker, wherein the rocker is movable relative to the first actuation rod against the spring force of the first compression spring.

[0031] Preferably, the first actuation rod extends through the first compression spring. By providing the first compression spring, the tensioning apparatus may accommodate different straps with different thicknesses since the rocker can be pushed away from the tensioning base against the spring force of the first compression spring in the active position of the tensioning apparatus. Furthermore, a desired contact force with which the tensioning wheel is to be pressed onto the strap while tensioning may be provided by using a first compression spring with a suitable spring constant.

[0032] In some embodiments, an actuating lever is connected to the rocker, wherein the second end of the first actuation rod is connected to the actuating lever.

[0033] The first actuation rod may therefore raise and lower the rocker by means of the actuating lever. The second end of the first actuation rod may be connected to the actuating lever by a hinge.

[0034] In some embodiments, the actuating lever may comprise an aperture in which the second end of the first actuation rod is slidably received.

[0035] The first compression spring may be arranged between the actuating lever and the first eccentric shaft such that the rocker may be movable with respect to the first eccentric shaft against the spring force of the first compression spring. With the actuating lever, a point of action for actuating the rocker with the first actuating rod can be provided. The actuation rod is preferably received with a tolerance in the aperture of the actuating lever. By providing a tolerance, a curved trajectory of the aperture when pivoting the rocker can be accommodated with the trajectory of the actuation rod.

[0036] In some embodiments, the first transmission comprises a first cam drivable by the first motor and a first follower operatively connected to the tensioning apparatus and configured to raise and / or lower the tensioning wheel with respect to the tensioning base.

[0037] With the first cam and the first follower, a simple mechanism to convert the rotatory motion of the first motor to a linear motion for lowering and / or raising the tensioning wheel can be provided.

[0038] In some embodiments, the strapping device comprises a first position sensor, preferably a first potentiometer or a first Hall sensor, configured to detect an angular position of a rotatory component of the first transmission.

[0039] By detecting the angular position of a rotatory component of the first transmission, the position of the tensioning wheel between the open position and the active position can be determined. The angular position of a rotatory component of the first transmission, for example an eccentric shaft or a cam, may therefore be used to control one or more strapping parameters depending on the position of the tensioning wheel. For example, the speed of lowering and / or raising may be varied depending on the position of the tensioning wheel. Since the operative connection between the first motor and the tensioning apparatus is continuous (and not interrupted by e.g. a coupling and / or a freewheel as in solutions with a shared motor between tensioning apparatus and joining apparatus), the position of the tensioning wheel may continuously be determined by monitoring the angular position of a rotatory component of the first transmission. Control of the tensioning process and therefore, the strapping process, can thereby be improved.

[0040] In some embodiments, the second actuating device comprises a second transmission configured to convert a rotatory motion of the second motor to a linear motion for raising and / or lowering the joining jaw with respect to the joining base.

[0041] Since the second actuating device can be dedicated for actuating the joining apparatus, the structure of the second transmission can be simplified to the conversion of the motor motion to an actuating motion for the joining jaw, without the need of a complex mechanism for diverting the motor motion to the tensioning apparatus. Furthermore, the rotary motion of the second motor can be reversed for lowering and raising the joining jaw, if needed, since the use of freewheels can be avoided.

[0042] In some embodiments, the second transmission comprises a second eccentric shaft drivable by the second motor, wherein the second eccentric shaft is operatively connected to the joining apparatus and configured to raise and / or lower the joining jaw with respect to the joining base.

[0043] Using the second eccentric shaft, the joining jaw can therefore be lowered and raised with respect to the joining base.

[0044] In some embodiments, the second transmission comprises a second actuation rod which is connected at a first end to the second eccentric shaft and at a second end to a pressure block to which the joining jaw is slidably connected.

[0045] The second actuation rod may therefore be lowered and raised by the second eccentric shaft being driven by the second motor and thereby lower and raise the joining jaw due to the connection of the second end of the second actuation rod to the pressure block. The joining jaw may be slidably connected to the pressure block so as to be movable perpendicular to the strap axis and in a plane parallel to the joining base.

[0046] In some embodiments, a second compression spring is arranged between the second eccentric shaft and the pressure block, wherein the joining jaw is movable relative to the second actuation rod against the spring force of the second compression spring.

[0047] Preferably, the second actuation rod extends through the second compression spring. By providing the second compression spring, the joining apparatus may accommodate different straps with different thicknesses since the joining jaw can be pushed away from the joining base against the spring force of the second compression spring in the active position of the joining apparatus. A desired contact force with which the joining jaw is to be pressed onto the strap while joining may be provided by using a second compression spring with a suitable spring constant.

[0048] In some embodiments, the pressure block comprises an aperture in which the second end of the second actuation rod is slidably received.

[0049] The second compression spring may be arranged between the pressure block and the second eccentric shaft such that the pressure block may be movable with respect to the second eccentric shaft against the spring force of the second compression spring. With the pressure block, a point of action for actuating the joining jaw with the second actuating rod can be provided.

[0050] In some embodiments, the second transmission comprises a second cam drivable by the second motor and a second follower operatively connected to the joining apparatus and configured to raise and / or lower the joining jaw with respect to the joining base.

[0051] With the second cam and the second follower, a simple mechanism to convert the rotatory motion of the second motor to a linear motion for lowering and / or raising the joining jaw can be provided.

[0052] In some embodiments, the strapping device comprises a second position sensor, preferably a second potentiometer or a second Hall sensor, configured to detect an angular position of a rotatory component of the second transmission.

[0053] By detecting the angular position of a rotatory component of the second transmission, the position of the joining jaw between the open position and the active position can be determined. The angular position of a rotatory component of the second transmission, for example an eccentric shaft or a cam, may therefore be used to control one or more strapping parameters depending on the position of the joining jaw. For example, the speed of lowering and / or raising may be varied depending on the position of the joining jaw. Since the operative connection between the second motor and the joining apparatus is continuous (and not interrupted by e.g. a coupling and / or a freewheel as in solutions with a shared motor between tensioning apparatus and joining apparatus), the position of the joining jaw may continuously be determined by monitoring the angular position of a rotatory component of the second transmission. Control of the joining process and therefore, the strapping process, can thereby be improved.

[0054] In some embodiments, the strapping device comprises a control unit connected to the first motor and the second motor, wherein the control unit is configured to control the first motor and the second motor such that an actuating motion on the joining apparatus and an actuating motion on the tensioning apparatus are executable at least partially concurrently.

[0055] The control unit can therefore independently control actuation of the tensioning apparatus and actuation of the joining apparatus due to the strapping device having a separate first motor for the tensioning apparatus and a separate second motor for the joining apparatus. The control unit may be configured to control the first motor and / or second motor with a respective actuation scheme that is adapted to the requirements of tensioning and / or joining. For example, it may be desirable to decelerate the tensioning wheel and the joining jaw to different extents and / or that the tensioning wheel and the joining jaw may be spaced at different distances to the tensioning base and the joining base, respectively, in each of the open positions. Due to the independent control of the actuation of the tensioning apparatus and the joining apparatus, the strapping process can be optimized.

[0056] According to a further aspect, a strapping device for strapping one or more articles with a strap is described, comprising a tensioning apparatus with a tensioning wheel for tensioning the strap around the one or more articles, a joining apparatus with a joining jaw for joining two overlapping portions of the strap, an actuating device comprising a motor and operatively connected to the tensioning apparatus, wherein the actuating device is, driven by the motor, configured to actuate the tensioning apparatus such that the tensioning wheel is lowerable from an open position to an active position towards a tensioning base for contacting the strap and raisable from the active position to the open position away from the tensioning base, wherein the actuating device comprises a transmission configured to convert a rotatory motion of the motor to a linear motion for raising and / or lowering the tensioning wheel with respect to the tensioning base, wherein the transmission comprises an eccentric shaft drivable by the motor, wherein the eccentric shaft is operatively connected to the tensioning apparatus and configured to raise and / or lower the tensioning wheel with respect to the tensioning base, wherein the tensioning wheel is rotatably mounted on the rocker, wherein a compression spring is arranged between the eccentric shaft and the rocker, wherein the rocker is movable relative to the eccentric shaft against the spring force of the compression spring.

[0057] By providing the compression spring, the tensioning apparatus may accommodate different straps with different thicknesses since the rocker can be pushed away from the tensioning base against the spring force of the compression spring in the active position of the tensioning apparatus. A desired contact force with which the tensioning wheel is to be pressed onto the strap while tensioning may be provided by using a compression spring with a suitable spring constant.

[0058] Providing the compression spring between the eccentric shaft and the rocker provides the advantage that the rocker is not supported against the housing of the strapping device, but against the movable eccentric shaft. Therefore, the rocker does not have to be raised against a spring force of a compression spring supported at the housing, but instead the compression spring may assist the rocker for the raising motion when the eccentric shaft is moved accordingly.

[0059] In some embodiments, the transmission comprises an actuation rod which is connected at a first end to the eccentric shaft and at a second end to a pivotable rocker.

[0060] Preferably, the actuation rod extends through the compression spring.

[0061] In some embodiments, an actuating lever is connected to the rocker, wherein the second end of the actuation rod is connected to the actuating lever.

[0062] The actuation rod may therefore raise and lower the rocker by means of the actuating lever. The second end of the actuation rod may be connected to the actuating lever by a hinge.

[0063] In some embodiments, the actuating lever may comprise an aperture in which the second end of the actuation rod is slidably received.

[0064] The compression spring may be arranged between the actuating lever and the eccentric shaft such that the rocker may be movable with respect to the eccentric shaft against the spring force of the compression spring. With the actuating lever, a point of action for actuating the rocker with the actuating rod can be provided. The actuation rod is preferably received with a tolerance in the aperture of the actuating lever. By providing a tolerance, a curved trajectory of the aperture when pivoting the rocker can be accommodated with the trajectory of the actuation rod.

[0065] In some embodiments, the transmission comprises a cam drivable by the motor and a follower operatively connected to the tensioning apparatus and configured to raise and / or lower the tensioning wheel with respect to the tensioning base.

[0066] With the cam and the follower, a simple mechanism to convert the rotatory motion of the motor to a linear motion for lowering and / or raising the tensioning wheel can be provided.

[0067] In some embodiments, the strapping device comprises a position sensor, preferably a potentiometer or a Hall sensor, configured to detect an angular position of a rotatory component of the transmission.

[0068] By detecting the angular position of a rotatory component of the transmission, the position of the tensioning wheel between the open position and the active position can be determined. The angular position of a rotatory component of the transmission, for example an eccentric shaft or a cam, may therefore be used to control one or more strapping parameters depending on the position of the tensioning wheel. For example, the speed of lowering and / or raising may be varied depending on the position of the tensioning wheel. The position of the tensioning wheel may therefore continuously be determined by monitoring the angular position of a rotatory component of the transmission.Brief description of the drawings

[0069] The present invention will be explained in more detail, by way of exemplary embodiments, with reference to the schematic drawing, in which: Fig.1shows an illustration of an interior part of an embodiment of a strapping device in a side view; Fig.2shows an illustration of an interior part of an embodiment of a strapping device in a side view; Fig.3shows an illustration of an interior part of an embodiment of a strapping device in a side view. Detailed description of exemplary embodiments

[0070] Figure 1 shows an interior part of an embodiment of a strapping device 100 in a side view. The strapping device 100 comprises a tensioning apparatus 1 and a joining apparatus 2. The tensioning apparatus 1 comprises a tensioning wheel 11 and a tensioning base 12 between which a strap S can be received. The tensioning wheel 11 is rotatably mounted on a rocker 13 and can be rotated around the rotation axis R, as symbolized by the arcuate arrow, for tensioning the strap S. An operating drive (not shown in Figure 1) drives the tensioning wheel 11 for executing the rotation around the rotation axis R. The rocker 13 is pivotably mounted in the housing 10 of the strapping device 100 and can be pivoted around the pivot axis P. The strapping device 100 may be a portable strapping device or a strapping head of a strapping machine.

[0071] The strapping device 100 comprises a first actuating device 14 which is operatively connected to the tensioning apparatus 1. The first actuating device 14 comprises a first motor 141 which is configured to drive the first actuating device 14 to actuate the tensioning apparatus 1 such that the tensioning wheel 11 is lowerable and raisable with respect to the tensioning base 12. The first actuating device 14 comprises a first transmission 14.1 configured to convert the rotatory motion of the first motor 141 to a linear motion for lowering and raising the tensioning wheel 11 with respect to the tensioning base 12. The first transmission 14.1 comprises a first eccentric shaft 142 which is rotatable by the first motor 141. The first actuating device 14 comprises a first actuation rod 143 which is connected at a first end 1431 to the first eccentric shaft 142 and at a second end 1432 to the rocker 13. An actuating lever 131 is connected to the rocker 13 and comprises an aperture in which the second end 1432 is slidably received with a radial tolerance. The second end 1432 has a flange-like termination 1433 by which the first actuation rod 143 can engage with the actuating lever 131 for raising the rocker 13.

[0072] A first compression spring 144 is arranged between the first eccentric shaft 142 and the actuating lever 131 of the rocker 13 such that the rocker 13 is movable relative to the first actuation rod 143 against the spring force of the first compression spring 144. The first actuation rod 143 extends through the compression spring 144. The first compression spring 144 abuts with a lower end at the actuating lever 131 such that the spring force of the compression spring 144 defines the contact force on the strap S when the tensioning wheel 11 is lowered onto the strap S by rotating the first eccentric shaft 142.

[0073] Thus, by rotating the first eccentric shaft 142, the tensioning wheel 11 can be lowered from the open position to the active position and raised from the active position to the open position with respect to the tensioning base 12.

[0074] The joining apparatus 2 is a friction welder comprising a joining jaw 21 and a joining base 22 between which overlapping portions Su and Sl of the strap S can be received. The joining jaw 21 is driven by the same operating drive that drives the tensioning wheel 11 for executing the welding motion. In some embodiments, a separate operating drive may be foreseen for driving the joining jaw 21.

[0075] The strapping device 100 further comprises a second actuating device 24 which is operatively connected to the joining apparatus 2. The second actuating device 24 comprises a second motor 241 which is configured to drive the second actuating device 24 to actuate the joining apparatus 2 such that the joining jaw 23 is lowerable and raisable with respect to the joining base 22. The second actuating device 24 comprises a second transmission 24.1 configured to convert the rotatory motion of the second motor 241 to a linear motion for lowering and raising the joining jaw 21 with respect to the joining base 22. The second transmission 24.1 comprises a second eccentric shaft 242 which is rotatable by the second motor 241. The second actuating device 24 comprises a second actuation rod 243 which is connected at a first end 2431 to the second eccentric shaft 242 and at a second end to a pressure block 23 or the joining jaw, respectively. The pressure block 23 comprises an aperture in which the second end (hidden by the pressure block 23 in Figure 1) of the second actuation rod 243 is slidably received. The joining jaw 21 is slidably connected to the pressure block 23 so as to be movable perpendicular to the strap axis and in a plane parallel to the joining base 22.

[0076] A second compression spring 244 is arranged between the second eccentric shaft 242 and the pressure block 23. The joining jaw 21 is movable relative to the second actuation rod 243 against the spring force of the second compression spring 244. The second actuation rod 243 extends through the compression spring 244. The second compression spring 244 abuts with a lower end at the pressure block 23 such that the spring force of the compression spring 244 defines the contact force on the overlapping portions Su and Sl of the strap S when the joining jaw 21 is lowered onto the overlapping portions Su and Sl of the strap S by rotating the second eccentric shaft 242.

[0077] Similar to the tensioning wheel 11, the joining jaw 21 can be lowered from the open position to the active position and raised from the active position to the open position with respect to the joining base 22 by rotating the second eccentric shaft 242.

[0078] The strapping device 100 comprises a control unit 3 connected to the first motor 141 and the second motor 241 and configured to control the first motor 141 and the second motor 241 such that an actuating motion on the joining apparatus 2 and an actuating motion on the tensioning apparatus 1 are at least partially concurrently executable.

[0079] Due to the first actuating device 14 with the first motor 141 and the second actuating device 24 with the second motor 241 being separate components, the tensioning apparatus 1 and the joining apparatus 2 can individually be controlled. In particular, it is possible to actuate one of the tensioning apparatus 1 or the joining apparatus 2 while actuating the other one without having to wait until one actuation is completed. For example, the joining jaw 21 may be lowered from an open position to an intermediate position simultaneously with the tensioning wheel 11 being lowered from an open position to its active position after introducing the strap S. The possibility of lowering the joining jaw 21 to an intermediate position while lowering the tensioning wheel 11 allows to define the open position of the joining apparatus 2 with a larger spacing between the joining jaw 21 and the joining base 22 since the joining jaw 21 only has to be moved from the intermediate position to the active position after tensioning is completed. By allowing the tensioning wheel 11 and / or the joining jaw 21 to assume different intermediate positions, the efficiency of strapping can be increased since actuation of one of the tensioning apparatus 1 or the joining apparatus 2 can be initiated before the actuation of the other is completed such that the actuating motions can run at least partially concurrently.

[0080] Figure 2 shows an interior part of an embodiment of a strapping device 100' in a side view. The structure of the strapping device 100' corresponds substantially to the structure of the strapping device 100 as shown in Figure 1. In addition, the strapping device 100' comprises a first position sensor 145' arranged at the first eccentric shaft 142' and configured to detect the angular position of a rotatory component of the first transmission 14.1', i.e. of the first eccentric shaft 142'. Similarly, the strapping device 100' comprises a second position sensor 245' arranged at the second eccentric shaft 242' and configured to detect the angular position of a rotatory component of the second transmission 24.1', i.e. the second eccentric shaft 242'. The strapping device 100' comprises a control unit 3' which receives the angular positions as determined by the first position sensor 145' and / or the second position sensor 245' and determines the position of the tensioning wheel 11' and / or the position of the joining jaw 21'. Depending on the determined position of the tensioning wheel 11' and / or the joining jaw 21', the control unit 3' may then control the actuation of the tensioning apparatus 1' and / or the joining apparatus 2'. For example, the control unit 3' may control the first actuating device 14' or the first motor 141' to vary the speed of lowering and / or raising of the tensioning wheel 11' depending on the determined height of the tensioning wheel 11' above the tensioning base 12'. Similarly, the control unit 3' may control the second actuating device 24' or the second motor 241' to vary the speed of lowering and / or raising of the joining jaw 21' depending on the determined height of the joining jaw 21' above the joining base 22'. For example, the tensioning wheel 11' and / or the joining jaw 21' can be decelerated while approaching their respective active positions.

[0081] Figure 3 shows an illustration of an interior part of an embodiment of a strapping device 100" in a side view. In contrast to the embodiments as shown in Figures 1 and 2, the axis of the first eccentric shaft 142" of the first transmission 14.1" is oriented parallel to the pivot axis P of the rocker 13". The eccentric shaft 142" is eccentrically arranged with respect to the motor axis 1411" of the first motor. In addition to the radial tolerance of the aperture of the actuating lever 131" where the first actuation rod 143" is received in, the flange-like termination 1433" of the first actuation rod 143" has a calotte-like profile in order to accommodate the eccentric motion of the eccentric shaft 142".

[0082] The axis of the second eccentric shaft 242" of the second transmission 24.1" arranged eccentrically with respect to the motor axis 2411" of the second motor is oriented parallel to the first eccentric shaft 142". Alternatively, the axes of the first eccentric shaft 142" and the second eccentric shaft 242" may be oriented perpendicular to each other. Similary, the first eccentric shafts 142, 142' and / or the second eccentric shafts 242, 242' of the embodiments as shown in Figures 1 and 2 may be oriented parallel to the pivot axis P of the rocker.

Claims

1. A strapping device (100, 100', 100") for strapping one or more articles with a strap (S), comprising a tensioning apparatus (1, 1') with a tensioning wheel (11, 11') for tensioning the strap around the one or more articles, a joining apparatus (2, 2') with a joining jaw (21, 21') for joining two overlapping portions (Sl, Su) of the strap, a first actuating device (14, 14') comprising a first motor (141, 141') and operatively connected to the tensioning apparatus, a second actuating device (24, 24') comprising a second motor (241, 241') and operatively connected to the joining apparatus, wherein the first actuating device is, driven by the first motor, configured to actuate the tensioning apparatus such that the tensioning wheel is lowerable from an open position to an active position towards a tensioning base (12, 12') for contacting the strap and raisable from the active position to the open position away from the tensioning base, and the second actuating device is, driven by the second motor, configured to actuate the joining apparatus such that the joining jaw is lowerable from an open position to an active position towards a joining base (22, 22') for contacting a portion of the strap overlapping another portion of the strap and raisable from the active position to the open position away from the joining base.

2. The strapping device (100, 100', 100") according to claim 1, wherein the first actuating device (14, 14') is configured to vary the speed of actuating the tensioning apparatus (1, 1') depending on the position of the tensioning wheel (11, 11') with respect to the tensioning base (12, 12').

3. The strapping device (100, 100', 100") according to one of the preceding claims, wherein the strapping device comprises an operating drive configured to drive the tensioning wheel (11, 11') for tensioning the strap (S) in the active position of the tensioning apparatus (1, 1') and / or the joining jaw (21, 21') for joining two overlapping portions (Sl, Su) of the strap in the active position of the joining apparatus (2, 2'), wherein the joining jaw (21, 21') is preferably movable between the open position and the active position while the operating drive drives the joining jaw.

4. The strapping device (100, 100', 100") according to one of the preceding claims, wherein the second actuating device (24, 24') is configured to vary the speed of actuating the joining apparatus (2, 2') depending on the position of the joining jaw (21, 21') with respect to the joining base (22, 22').

5. The strapping device (100, 100', 100") according to one of the preceding claims, wherein the first actuating device (14, 14') comprises a first transmission (14.1, 14.1', 14.1") configured to convert a rotatory motion of the first motor (141, 141') to a linear motion for raising and / or lowering the tensioning wheel (11, 11') with respect to the tensioning base (12, 12').

6. The strapping device (100, 100', 100") according to claim 5, wherein the first transmission (14.1, 14.1', 14.1") comprises a first eccentric shaft (142, 142', 142") drivable by the first motor (141, 141'), wherein the first eccentric shaft is operatively connected to the tensioning apparatus (1, 1') and configured to raise and / or lower the tensioning wheel (11, 11') with respect to the tensioning base (12, 12'), wherein the first transmission (14.1, 14.1', 14.1") preferably comprises a first actuation rod (143, 143") which is connected at a first end (1431) to the first eccentric shaft (142, 142', 142") and at a second end (1432) to a pivotable rocker (13, 13"), wherein the tensioning wheel (11, 11') is rotatably mounted on the rocker (13, 13").

7. The strapping device (100, 100', 100") according to claim 6, wherein a first compression spring (144) is arranged between the first eccentric shaft (142, 142') and the rocker (13, 13"), wherein the rocker is movable relative to the first actuation rod (143, 143") against the spring force of the first compression spring (144), wherein an actuating lever (131, 131") is preferably connected to the rocker (13, 13"), wherein the second end (1432) of the first actuation rod (143, 143") is preferably connected to the actuating lever.

8. The strapping device according to claim 5, wherein the first transmission comprises a first cam drivable by the first motor and a first follower operatively connected to the tensioning apparatus and configured to raise and / or lower the tensioning wheel with respect to the tensioning base.

9. The strapping device (100') according to one of the claims 5 to 8, comprising a first position sensor (145'), preferably a first potentiometer or a first Hall sensor, configured to detect an angular position of a rotatory component (142') of the first transmission (14.1').

10. The strapping device (100, 100', 100") according to one of the preceding claims, wherein the second actuating device (24, 24') comprises a second transmission (24.1, 24.1', 24.1") configured to convert a rotatory motion of the second motor (241, 241') to a linear motion for raising and / or lowering the joining jaw (21, 21') with respect to the joining base (22, 22').

11. The strapping device (100, 100', 100") according to claim 10, wherein the second transmission (24.1, 24.1', 24.1") comprises a second eccentric shaft (242, 242', 242") drivable by the second motor (241, 241'), wherein the second eccentric shaft is operatively connected to the joining apparatus (2, 2') and configured to raise and / or lower the joining jaw (21, 21') with respect to the joining base (22, 22'), wherein the second transmission (24.1, 24.1', 24.1") preferably comprises a second actuation rod (243) which is connected at a first end (2431) to the second eccentric shaft (242, 242', 242") and at a second end to a pressure block (23) to which the joining jaw (21, 21') is slidably connected.

12. The strapping device (100, 100', 100") according to claim 11, wherein a second compression spring (244) is arranged between the second eccentric shaft (242, 242', 242") and the pressure block (23), wherein the joining jaw (21, 21') is movable relative to the second actuation rod (243) against the spring force of the second compression spring (244), wherein the pressure block preferably comprises an aperture in which the second end of the second actuation rod (243) is slidably received.

13. The strapping device according to claim 10, wherein the second transmission comprises a second cam drivable by the second motor and a second follower operatively connected to the joining apparatus and configured to raise and / or lower the joining jaw with respect to the joining base.

14. The strapping device (100') according to one of the claims 10 to 13, comprising a second position sensor (245'), preferably a second potentiometer or a second Hall sensor, configured to detect an angular position of a rotatory component (242') of the second transmission (24.1').

15. The strapping device (100, 100') according to one of the preceding claims, comprising a control unit (3, 3') connected to the first motor (141, 141') and the second motor (241, 241'), wherein the control unit (3, 3') is configured to control the first motor and the second motor such that an actuating motion on the joining apparatus (2, 2') and an actuating motion on the tensioning apparatus (1, 1') are executable at least partially concurrently.

Images