Tensioning device, in particular for a returnable packaging

Abstract

The invention relates to a tensioning device for a tensioning strap. The tensioning device comprises a winding drum (7) which is rotatably arranged on a drum holder. One end of the tensioning strap (5) is fastened to the circumferential surface of the winding drum (7), and the tensioning strap (5) can be wound onto the winding drum (7). The tensioning device comprises a drive shaft (10) which extends along the axis of rotation of the winding drum (7) and which is arranged in the winding drum (7) for conjoint rotation and such that the drive shaft is axially movable, the drive shaft (10) having a coupling profile (12) for connecting to a rotary tool for conjoint rotation. The tensioning device comprises a first toothed ring (15) which is rotationally fixed on the drum holder and which has saw teeth. The tensioning device comprises a second toothed ring (16) which is connected to the drive shaft (10) for conjoint rotation and which has saw teeth which are complementary to and face the saw teeth of the first toothed ring (15). The tensioning device comprises a spring element (20) which presses the second toothed ring (16) against the first toothed ring (15) in a first axial direction. By axial pressure against the coupling profile (12) of the drive shaft (10), the second toothed ring (16) is pressed away from the first toothed ring (15) in a second axial direction against the spring force of the spring element (20). Said tensioning device (4) can be used in a returnable packaging and allows secure tensioning of the tensioning strap (5) and easy handling of the tensioning mechanism, using simple means.

Description

Clamping device, especially for a circular packaging Technical field

[0001] The invention relates to a tensioning device for a tensioning strap. The tensioning device for a tensioning strap is particularly intended for use in a circular packaging system designed to form a stable and damage-protected loading unit for cargo containing reusable elements.

[0002] For environmental reasons and to avoid packaging waste, reusable circular packaging is increasingly being used to form stable loading units for transporting goods, for example, from the manufacturer to the point of sale or processing plant. The loading unit typically consists of a load carrier, such as a pallet, and a cargo cover containing the straps and tensioning devices for the straps. Both the cargo cover and the pallet are reused after the loading unit has been transported to its destination and used to form a new loading unit.

[0003] Such a circulating packaging system is known, for example, from European Patent EP 1 289 850 B1. This patent describes a load securing device for use with a pallet, in which the tensioning straps can be received by linearly displaceable deflection shafts in the cargo cover. In an alternative embodiment shown in Figures 11 to 15, a tensioning rope is wound onto a spool as the tensioning device, which, via a pawl, tensions the rope. Subsequent patents of the same applicant, e.g., WO 2023 / 119211 A1, WO 2024 / 047600 A1, EP 4 054 895 B1, and WO 2022 / 234531 A1, show that the applicant has focused on tensioning straps that can be wound onto a winding drum. The axis of the winding drum lies perpendicular to the substantially horizontal cargo cover, and the tensioning strap is wound onto this winding drum in a perpendicular orientation.After unwinding from the winding drum, the tensioning strap is redirected and guided horizontally out of the cargo cover. The strap is then guided through the slot of a slotted, horizontal tensioning shaft and tensioned by winding it onto the shaft. A pawl locks the tensioning shaft in its tensioned position.

[0004] Similar slotted tensioning shafts are also known from US 8,434,979 B1. Various variations of tensioning devices, especially for cables, are known from WO 2020 / 247636 A1.

[0005] Documents WO 2024 / 012890 A1, GB 2 474 912 A and GB 2 455 290 A describe various drives for a winding drum of a tensioning belt, in which differently designed pawls lock the movement of the winding drum when the tensioning belt is under tension.

[0006] It is desirable to provide a tensioning device for a tensioning strap, especially for use in a circular packaging system, which allows for secure tensioning of the tensioning strap and easy handling of the tensioning mechanism using simple means.

[0007] This problem is solved by the features of the patent claim.

[0008] The tensioning device for a tensioning strap comprises the following: a winding drum rotatably mounted on a drum holder, wherein one end of the tensioning strap is attached to the circumferential surface of the winding drum and the tensioning strap can be wound onto the winding drum; a drive shaft extending along the axis of rotation of the winding drum and arranged in the winding drum in a rotationally fixed and axially displaceable manner, wherein the drive shaft has a coupling profile for a rotationally fixed connection with a rotary tool; a first toothed ring with saw teeth arranged rotationally fixed to the drum holder; a second toothed ring with saw teeth connected rotationally fixed to the drive shaft, the saw teeth being complementary to and opposite the saw teeth of the first toothed ring; a spring element which presses the second toothed ring against the first toothed ring in a first axial direction.wherein, by axial pressure against the coupling profile of the drive shaft, the second toothed ring is pushed away from the first toothed ring in a second axial direction against the spring force of the spring element.

[0009] The tensioning strap is tensioned directly by winding it onto the winding drum, which is achieved by rotating the drive shaft running along the drum's axis of rotation. Two toothed rings with saw teeth form a locking mechanism. The first toothed ring is fixed to the drum's mounting bracket. The second toothed ring is fixed to an axially displaceable drive shaft on the winding drum. The interlocking sawtooth profiles of the two toothed rings prevent the drive shaft, and thus the winding drum, from rotating relative to the drum's mounting bracket in one direction. The winding drum's rotation is locked in the direction in which the tensioning strap is unwound. However, rotation of the drive shaft, and therefore the winding drum, is possible in the direction in which the tensioning strap is wound onto the drum.For tensioning, a suitable turning tool is connected to the coupling profile of the drive shaft and used to apply torque in the winding direction. The angled flanks of the saw teeth slide against each other, allowing the drive shaft and thus the winding drum to rotate. After tensioning, the turning tool can be removed. The straight flanks of the interlocking saw tooth profiles, which run essentially perpendicular to the direction of rotation and are pressed against each other by the spring element, prevent the tension from being released by unwinding the tensioning belt from the winding drum.

[0010] The tensioning strap can also be released using a tool that engages the coupling profile. This tool is used to press in the axially displaceable drive shaft, thereby moving the sawtooth profiles of the two toothed rings apart. This deflects the spring element against its spring force. In this state, the rotary tool can be driven in the direction of the tensioning strap's unwinding. Alternatively, the tool connected to the coupling profile can be held freely rotatable, so that the tension of the tensioning strap itself causes the winding drum to rotate in the unwinding direction. It is also possible to release the tension without a rotationally fixed coupling to the coupling profile. Simply applying axial pressure to the free end of the drive shaft is sufficient to separate the sawtooth profiles.

[0011] The free end of the ratchet strap is usually attached to the pallet via a fastener, such as a hook. When the ratchet strap is slack, the fastener can be released. The winding tool can then be turned again in the winding direction to wind the ratchet strap as far as possible onto the winding drum.

[0012] In practice, the clamping device can include a pressure plate against which the spring element presses, and an axial bearing that transmits the compressive forces from the pressure plate to the second toothed ring. This ensures that the drive shaft remains freely rotatable even when a compressive force is applied to the spring device. The axial bearing transmits the axial compressive forces and enables smooth rotation.

[0013] To ensure a rotationally fixed and axially displaceable connection between the drive shaft and the winding drum and / or the second toothed ring, the drive shaft is preferably positively connected to the winding drum or the second toothed ring. The drive shaft can be designed as a splined shaft and extend through a complementarily shaped hub section that is connected to the winding drum or the second toothed ring. Alternatively, the drive shaft can have a polygonal profile, e.g., a square profile, and extend through a complementarily shaped hub section that is connected to the winding drum or the second toothed ring. Finally, the drive shaft can have at least one recess into which a drive element is inserted, which engages in a corresponding recess of a hub section that is connected to the winding drum or the second toothed ring.Different shaft-hub connections can also be used, for example a drive element for connection with the second pinion and a polygon profile for connection with the winding drum.

[0014] A coupling profile is any profile arranged on the drive shaft that allows a rotary tool to be positively connected to transmit torque to the drive shaft. The coupling profile is typically located at the free, externally accessible end of the drive shaft. However, it can also be positioned further away from the free end. It can be designed in any way necessary to securely connect a rotary tool to the drive shaft. For example, a simple radial through-hole would be suitable for inserting a pin-shaped rotary tool radially into the through-hole to rotate the drive shaft. However, a pin-shaped rotary tool is not well-suited for applying axial compressive forces to the end of the drive shaft.In practice, coupling profiles can be selected that, for example, can be used as screw drives and simultaneously allow the application of torque and axial force. Examples of such coupling profiles are: External hexagon, i.e., the shaft end has a hexagonal head, similar to a screw head. A hexagonal section can also be located at a certain distance from the shaft end. If the hexagonal section has a larger diameter than the adjacent areas of the drive shaft, compressive forces can also be applied to the drive shaft via it. Internal hexagon, also known in Germany under the registered trademark Inbus. The shaft end has a hexagonal recess into which a screwdriver with an axial cross-section is inserted in the axial direction. Internal hexagon, also known under the registered trademark Torx.The shaft end has a star-shaped recess into which a screw tool with a complementary star-shaped cross-section is inserted axially. It is also possible to form the cross-section of the shaft end in a star shape, with the screw tool having a star-shaped recess.

[0015] As mentioned at the beginning, the tensioning drive is intended for a circular packaging which has the following: a cargo carrier; a cargo cover; at least two tensioning straps which connect the cargo carrier to the cargo cover.

[0016] To ensure easy and reliable handling of the tensioning strap, one end of each tensioning strap is attached to the winding drum of a tensioning device according to one of the preceding claims, with a fastening means arranged at the other end of the tensioning strap. For storage, the tensioning strap can be completely wound onto the winding drum. When cargo carriers and cargo covers are used to form a load unit with cargo placed between them, the tensioning straps are unwound from the winding drum and tensioned so that they stabilize the load unit. Two or more tensioning straps can also be attached to the circumference of a winding drum. These tensioning straps are then unwound and wound up simultaneously.

[0017] In practice, the drum bracket can be mounted on the load carrier and / or the load cover. The drum brackets are most often mounted on the load cover. Standard pallets, such as Euro pallets, are typically used as load carriers. The load covers serve as lids for the loading unit and feature the winding drums with the tensioning straps wound onto them. The tensioning devices are operated from above. Alternatively, the tensioning devices can also be integrated into drum brackets on the load carrier. If this option is chosen, the coupling profile of the drive shaft on the load carrier should be freely accessible.

[0018] In practice, the circular packaging can have four tensioning devices for four tensioning straps, with the cargo cover having four receptacles, each forming a drum holder for a winding drum. In other words, each tensioning strap is wound onto a separate winding drum. The tensioning straps can thus be individually unwound, attached to the cargo carrier with the fastening devices, and tensioned.

[0019] In practice, the axis of the winding drum can extend essentially perpendicular to the plane of the load carrier and / or the load cover. Particularly when the drum mount is located on the load cover, a winding drum with a vertical winding shaft can be positioned such that the coupling profile at the end of the winding shaft is located at the top and accessible from above. Furthermore, a deflecting element with a guide channel for the tensioning strap can be arranged between the winding drum and the edge of the load cover. This guide guides the tensioning strap from the plane parallel to the axis of the winding drum to the plane parallel to the plane of the load carrier and / or the load cover. The tensioning strap is wound onto the winding drum with an orientation parallel to the axis of the winding drum. To tension the load cover and the load carrier together, the tensioning straps should be parallel to the plane of the load cover or load cover.The tensioning straps must be aligned with the load carrier. If the loading unit has a cuboid shape, the tensioning straps can lie flat against each side wall of the loading unit in this orientation. For this purpose, the tensioning straps can rest on a support element, such as a guide roller or deflection edge, which extends in the plane of the load cover or load carrier. A deflection element that guides the tensioning straps and rotates them into the plane of the load cover or load carrier ensures that the tensioning straps are guided cleanly when being pulled off or wound onto the winding drum and are wound onto the drum in smooth, overlapping layers.

[0020] Handling the tensioning devices and the resulting circular packaging is very simple and easily automated. In one method for handling circular packaging, the cargo is placed on the cargo carrier, and the cargo cover is placed on top. The tensioning straps are pulled off the winding drum, which is usually located on the cargo cover, and attached to the cargo carrier using the fasteners. If the winding drums are integrated into the cargo carrier, the ends of the tensioning straps are hooked onto the cargo cover. Winding the straps onto the winding drum tightens them.

[0021] To tension a ratchet strap, a rotary tool can be connected to the coupling profile of the drive shaft. Using this tool, a torque is applied to the drive shaft in the winding direction without any axial force. When the drive shaft is not being pushed axially by the rotary tool, the spring element presses the sawtooth profiles of the toothed rings against each other. As the tool rotates in the winding direction, the angled flanks of the sawtooth profiles slide against each other. The vertical flanks of the sawtooth profiles, however, prevent rotation in the opposite direction, thus maintaining the applied tension.

[0022] To release the tensioned tensioning strap, a rotary tool can be connected to the coupling profile. An axial force is applied to the drive shaft using the rotary tool, which can rotate freely, or a torque can be applied to the drive shaft in the unwinding direction. The rotary tool pushes the drive shaft axially, causing the second toothed ring to move away from the first. When the perpendicular flanks of the sawtooth profiles no longer overlap axially, the winding drum can rotate in the unwinding direction. If the rotary tool is free to rotate, the tensile force of the tensioned tensioning strap causes the winding drum to rotate in the unwinding direction. Alternatively, the rotary tool can be driven in the unwinding direction. The tensioning strap can also be released without a rotary tool.It is sufficient to apply an axial pressure force to the free end of the drive shaft manually or with a hard object to cause the clamping device to release.

[0023] Cargo covers or cargo carriers with tensioning devices are typically stored with all tensioning straps fully wound onto the winding drums. To assemble a load unit, a significant length of tensioning strap must be unwound from the winding drum to connect the cargo cover and the cargo carrier. The tensioning strap can be removed from the winding drum as follows: a rotary tool is connected to the coupling profile, and an axial force is applied to the drive shaft using this tool. Simultaneously, the fastening device is pulled. The rotary tool can either rotate freely or apply a torque to the drive shaft in the unwinding direction.Once the required length of tensioning strap has been pulled from the winding drum, axial pressure is no longer applied to the drive shaft, so the two opposing toothed rings prevent further pulling of the tensioning strap. Here, too, it is possible to apply axial pressure to the drive shaft manually, for example, without a rotary tool. The use of rotary tools is preferred when the handling of the loading units is to be automated. In this case, robot arms or other manipulation devices can automatically move the rotary tools to the coupling profiles and drive them as described to assemble or disassemble the loading unit.

[0024] After the loading unit is unwound, it may be necessary to rewind the entire length of the tensioning strap that was pulled off the winding drum. To wind the tensioning strap onto the winding drum, a rotary tool can be connected to the coupling profile, and an axial force can be applied to the drive shaft using the rotary tool. This rotary tool then applies a torque in the winding direction to the drive shaft. By axially pressing the drive shaft, the tooth profiles of the toothed rings are separated and no longer make contact. The tensioning strap is then wound up with minimal effort and without noise.

[0025] Practical embodiments and advantages of the invention are described below in connection with the drawings.

[0026] shows a perspective view of a loading unit with four tension straps

[0027] shows a front view of the charging unit.

[0028] shows a perspective view of a longitudinal section of the loading unit from the inside.

[0029] shows an enlarged view of the clamping device of the loading unit in a perspective longitudinal section.

[0030] shows a side view of the largely isolated clamping device.

[0031] shows a corresponding view with the drive shaft pressed in axially.

[0032] The recognizable loading unit consists of a load carrier 1, a load cover 2, and the load 3 arranged between them. In this case, the load carrier 1 is a Euro pallet. However, a different design of load carrier 1 can also be used, for example, a special pallet adapted to the load 3 arranged on it. It is also possible to integrate the clamping device described below into the load carrier 1 if the coupling profiles of the drive shaft of this clamping device are accessible from the outside. This is the case if the surface of the load carrier 1 is not completely covered with load 3 or has outwardly protruding sections.

[0033] In this case, the cargo 3 is essentially depicted as a closed cube. It could be a container holding individual products. However, the cargo 3 could also consist of several boxes, for example, made of corrugated cardboard. The height of the cargo 3 can vary. The cargo cover 2 is placed on top of the cargo 3. Several recesses are formed in the cargo cover 2, which, on the one hand, accommodate tensioning devices 4 for tensioning straps 5 and, on the other hand, ensure the dimensional stability of the cargo cover 2. The cargo cover 2 can be made of thermoformed plastic, for example. However, it can also be made of deep-drawn sheet metal, particularly aluminum or steel sheets. There are few restrictions regarding the choice of material. It is only necessary to ensure that the cargo cover 2 is sufficiently stable.A cargo cover made of thermoformed plastic or deep-drawn aluminum is also lightweight and reduces transport weight. The cargo cover can also be formed from a grid structure, either open or covered only by a thin layer of plastic or metal. A wooden structure, such as a Euro pallet, can also be used as a cargo cover, with the deck boards resting on the cargo.

[0034] The tensioning straps 5 have fastening elements at their free ends, which are designed as hooks 6 and can be hooked onto the load carrier 1, namely the pallet 1, to stabilize the load unit. After the hooks 6 are engaged, the tensioning straps 5 are tensioned by the tensioning devices 4. The fastening elements can also differ from the hooks 6 shown. For example, fastening elements can be used that engage in complementary shaped receptacles on the load carrier.

[0035] The tensioning devices 4 are preferably integrated within the cargo cover 2, i.e., they have no protruding parts. Because no components of the tensioning devices 4 protrude from the contour of the cargo cover 2, damage during transport is avoided. The tensioning straps 5 are typically made of textile webbing of synthetic yarns. However, natural yarns, such as cotton or hemp fibers, can also be used.

[0036] The tensioning device 4 for the tensioning strap 5 is shown in the figure. For the sake of clarity, the tensioning strap 5 itself is not shown.

[0037] The tensioning device 4 essentially consists of a winding drum 7. The tensioning strap 5 (not shown) can be attached to the circumference of the winding drum 7 by means of a clamping strip 8 and two fastening screws 9 (only the lower one is marked with a reference numeral). The winding drum 7 is arranged on a drive shaft 10. The drive shaft 10 is axially displaceable relative to the winding drum 7, but is rotationally fixed to the winding drum 7. In the illustrated embodiment, the drive shaft 10 and the winding drum 7 have longitudinal grooves of the same width in which a key 11 engages to connect the two components rotationally fixedly. The key 11 forms the drive element that transmits the rotational movement from the drive shaft 10 to the winding drum 7.Alternative positive-locking connections can be achieved through non-circular profiles of the drive shaft 10 and the corresponding recesses in the winding drum 7. For example, the drive shaft 10 can have a square profile and the shaft receptacle of the winding drum 7 a corresponding cross-section. Alternatively, a splined shaft can be used as the drive shaft 10 with a corresponding cross-section for the receptacle bore of the winding drum 7.

[0038] The upper end of the drive shaft 10 has a coupling profile 12. In this case, the coupling profile 12 is designed as an internal hexagonal recess. However, as mentioned, any profile can be used that allows a positive-locking and rotationally fixed engagement of a turning tool.

[0039] The winding drum 7 is rotatably mounted in two aligned recesses in an upper wall section 13 and a lower wall section 14 of the cargo cover 2. The upper wall section 13 and the lower wall section 14 together form the drum support for the winding drum 7. A fixed first toothed ring 15 is mounted on the underside of the lower wall section 14. The first toothed ring 15 is preferably made of steel. If the lower wall section 14 is also made of steel, the first toothed ring 15 can be welded to the lower wall section 14. Alternatively, a screw connection, rivet connection, or other positive-locking connecting elements can be provided to non-rotatably connect the first toothed ring 15 to the lower wall section 14.

[0040] A second toothed ring 16 is mounted in the area of ​​the drive shaft 10 located below the first toothed ring 15. The second toothed ring 16 has a hub section 17 in its center, through which the drive shaft 10 extends. A key 18 is again provided, which engages in aligned grooves in the drive shaft 10 and the hub section 17 of the second toothed ring 16. The key 18 forms the driving element, which connects the drive shaft 10 to the second toothed ring 16 in a rotationally fixed manner.

[0041] A cup-shaped section 19 of the cargo cover 2 surrounds the lower end of the drive shaft 10. A spring element 20, designed as a helical compression spring, rests on this cup-shaped section 19 and presses against a shoulder 21 of a pressure plate 22. The pressure plate 22 rests against a lower bearing shell of a thrust bearing 23. The upper bearing shell of the thrust bearing 23 rests against the second toothed ring 16. In this way, the spring element 20 presses the toothed surface of the second toothed ring 16 against the toothed lower surface of the first toothed ring 15. The thrust bearing 23 ensures that, despite the spring force, the second toothed ring 16 can rotate freely relative to the pressure plate.

[0042] For better clarity, only the parts of the tensioning device are shown, in particular the toothed rings 15 and 16 attached to the drive shaft 10, as well as the upper wall section 13 and the lower wall section 14 of the cargo cover 2. The tensioning strap 5 wound onto the winding drum 7 and the deflecting element 26 for the tensioning strap 5 are also visible. It can be seen that the tensioning strap 5 is wound vertically onto the winding drum 7 and enters a guide channel 27 (cf.) of the deflecting element 26. On the left side, it exits the guide channel 27 of the deflecting element 26 in a horizontal orientation.

[0043] As can be seen in Figure 6, the toothed surfaces of the first toothed ring 15 and the second toothed ring 16 are provided with complementary sawtooth profiles. Each sawtooth profile has a sequence of long, inclined flanks 24 followed by short, axially extending flanks 25. It can be seen that the axially extending flank 25 prevents the two axially pressed toothed rings 15 and 16 from rotating, whereas the inclined flanks 24 allow them to slide against each other, so that the two toothed rings 15 and 16 can only be rotated relative to each other in one direction. The direction of rotation that is free when the toothed rings 15 and 16 are axially pressed against each other is the winding direction for the tensioning strap 5. In this way, a torque can be introduced into the drive shaft 10 via the coupling profile 12, tensioning the tensioning strap 5 by winding it onto the winding drum 7. Relaxation is blocked when tooth rings 15, 16 are pressed axially against each other.

[0044] By axially pressing the drive shaft 10, the toothed rings 15 and 16 can be disengaged. This state is shown. It can be seen that the drive shaft 10 is displaced downwards by a few millimeters and carries the lower, second toothed ring 16 with it. The tooth profiles of the lower, second toothed ring 16 and the upper, first toothed ring 15 no longer mesh, so that the toothed rings 15 and 16 can be rotated freely in both directions.

[0045] In the illustrated embodiment, the axial compressive force on the drive shaft 10 is simply introduced via the coupling profile 12, namely the internal hexagon. The turning tool is simply pressed in the axial direction to compress the spring element 20 and disengage the tooth profiles of the toothed rings 15, 16. The axial bearing 23 ensures that, despite the axial force exerted on the pressure plate 22 by the spring element 20, relatively smooth rotation of the drive shaft 10 is possible.

[0046] The concealed deflection element 26 prevents the tensioning strap 5 from wrinkling, twisting, or being wound onto the winding drum 7 in any other uncontrolled manner. It ensures that the tensioning strap 5 is always wound smoothly onto the winding drum 7 in successive layers.

[0047] To tension the tensioning strap 5, a torque is applied to the drive shaft 10 using a rotary tool that engages the coupling profile 12 of the drive shaft 10, without introducing an axial force into the drive shaft 10. The spring element 20 presses the toothed rings 15, 16 axially against each other so that their tooth profiles abut each other. During this tensioning process, the toothed rings 15, 16 can only be rotated relative to each other in one direction. This state is shown in the figure.

[0048] To release a tensioned tensioning strap 5, an axial compressive force is simply applied to the coupling profile 12, which displaces the lower, second toothed ring 16, coupled to the drive shaft 10, into the position shown and moves it away from the upper, first toothed ring 15. This disengages the tooth profiles of the toothed rings 15 and 16, and the inherent tension of the tensioning strap 5 pulls the strap 5 away from the winding drum 7 in the unwinding direction. For this to occur, it is sufficient that the winding drum is freely rotatable. If the axial force is applied by the rotary tool engaging the coupling profile 12, the rotary tool can be freely rotatable for releasing the tensioning strap 5. For example, the rotary tool can be motor-driven and mounted on a machine manipulator, such as a robot arm. In this case, it is sufficient to disengage the drive motor of the rotary tool.Alternatively, an axial compressive force can simply be applied manually to the coupling profile 12 by pressing a manually grasped hexagonal key into the coupling profile 12. With the drive shaft 10 axially pressed in, a rotary movement can also be initiated in the axial direction via the coupling profile 12 into the drive shaft 10 to release the tension strap 5.

[0049] To quickly pull the tensioning strap 5 off the winding drum 7, axial pressure can also be applied to the drive shaft 10 using a rotary tool, while simultaneously pulling on the hook (fastening element 6). Again, the rotary tool can be freely rotatable or it can apply a torque in the unwinding direction to the drive shaft 10. This pulling action occurs, for example, when the cargo cover 2 is placed on the cargo 3 and the tensioning straps 5 are pulled off to attach the fastening elements 6 to the cargo carrier 1.

[0050] Similarly, an axial force can be applied to the drive shaft 10 for the rapid winding of the tensioning strap 5. The rotary tool then rotates the drive shaft 10 in the winding direction, so that the tensioning strap 5 is wound onto the winding drum 7. Unlike when tensioning the tensioning strap 5, the axial pressure on the drive shaft 10 disengages the tooth profiles of the toothed rings 15, 16.

[0051] The clamping device described here enables both the automatic assembly of a loading unit in an automated packing station using motor-driven rotary tools repositioned by numerically controlled manipulators (robot arms), and the manual assembly of loading units using the corresponding manually operated rotary tools. The removal of the cargo from the loading unit can also be performed manually or automatically, enabling fully automated bidirectional input and output flows of cargo in logistics centers.

[0052] The features of the invention disclosed in this description, in the drawings, and in the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention is not limited to the described embodiments. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

[0053] 1 Cargo carrier, pallet 2 Cargo cover 3 Cargo 4 Tensioning device 5 Tensioning strap 6 Fastening device, hook 7 Winding drum 8 Clamping strip 9 Mounting screw 10 Drive shaft 11 Key, drive element 12 Coupling profile, internal hexagon 13 Upper wall section 14 Lower wall section 15 First toothed ring 16 Second toothed ring 17 Hub section 18 Key, drive element 19 Cup-shaped section 20 Spring element 21 Shoulder 22 Pressure plate 23 Thrust bearing 24 Long inclined flank 25 Short axial flank 26 Deflection element 27 Guide channel

Claims

Tensioning device (4) for a tensioning strap (5), comprising a winding drum (7) rotatably mounted on a drum holder, wherein one end of the tensioning strap (5) is attached to the circumferential surface of the winding drum (7) and the tensioning strap (5) can be wound onto the winding drum (7), a drive shaft (10) extending along the axis of rotation of the winding drum (7) and arranged in the winding drum (7) in a rotationally fixed and axially displaceable manner, wherein the drive shaft (10) has a coupling profile (12) for a rotationally fixed connection with a rotary tool, a first toothed ring (15) with saw teeth arranged rotationally fixed on the drum holder, a second toothed ring (16) with saw teeth connected rotationally fixed to the drive shaft (10), the saw teeth being complementary to and opposite the saw teeth of the first toothed ring (15), and a spring element (20) which presses the second toothed ring (16) against the first toothed ring (15) in a first axial direction.wherein, by axial pressure against the coupling profile (12) of the drive shaft (10), the second toothed ring (16) is pushed away from the first toothed ring (15) in a second axial direction against the spring force of the spring element (20). Clamping device (4) according to the preceding claim, further comprising a pressure plate (22) against which the spring element (20) presses, and an axial bearing (23) which transmits the pressure forces from the pressure plate (22) to the second toothed ring (16). Clamping device (4) according to one of the preceding claims, characterized in that the rotationally fixed and axially displaceable connection of the drive shaft (10) with the winding drum (7) and / or the second toothed ring (16) has at least one of the following features: the drive shaft (10) is designed as a splined shaft and extends through a complementarily shaped hub section which is connected to the winding drum (7) or to the second toothed ring (16); the drive shaft (10) has a polygonal profile and extends through a complementarily shaped hub section which is connected to the winding drum (7) or to the second toothed ring (16); the drive shaft (10) has at least one recess into which a drive element (11, 18) is inserted, which engages in a corresponding recess of a hub section (17) which is connected to the winding drum (7) or to the second toothed ring (16). Clamping device (4) according to one of the preceding claims, characterized in that the coupling profile (12) of the drive shaft (10) is selected from the following: external hexagon, internal hexagon (12), internal hexagon, external hexagon. Circulating packaging comprising a cargo carrier (1); a cargo cover (2); at least two tensioning straps (5) which connect the cargo carrier (1) to the cargo cover (2), characterized in that one end of each tensioning strap (5) is attached to the winding drum (7) of a tensioning device (4) according to one of the preceding claims, wherein a fastening means (6) is arranged at the other end of the tensioning strap (5). Circulating packaging according to claim 5, characterized in that the drum holder is arranged on the cargo carrier (1) and / or on the cargo cover (2). Circulating packaging according to claim 5 or 6, characterized in that the cargo cover (2) has a receptacle for each tensioning device (4), each of which forms a drum holder for a winding drum (7). Circulating packaging according to one of claims 5 to 7, characterized in that the axis of the winding drum (7) extends substantially perpendicular to the plane of the cargo carrier (1) and / or the cargo cover (2) and that a deflecting element (26) with a guide channel (27) for the tensioning belt (5) is arranged between the winding drum (7) and the edge of the cargo cover (2), which guides the tensioning belt (5) from the plane parallel to the axis of the winding drum (7) to the plane parallel to the plane of the cargo carrier (1) and / or the cargo cover (2). A method for handling a circulating packaging according to one of claims 5 to 8, wherein cargo is placed on the cargo carrier (1) and the cargo cover (2) is placed on the cargo, and the tensioning straps (5) are pulled from the winding drum (7) on the cargo carrier (1) and / or the cargo cover (2) and attached to the cargo cover (2) or the cargo carrier (1) with the fastening means (6) and tensioned by winding onto the winding drum (7), characterized by at least one of the following steps: to tension a tensioning strap (5), a rotary tool is connected to the coupling profile (12) of the drive shaft (10) and a torque in the winding direction is introduced into the drive shaft (10) with the rotary tool without axial force;To release the tensioned tensioning strap (5), a rotary tool is connected to the coupling profile (12), and an axial force is applied to the drive shaft (10) by means of the rotary tool, wherein the rotary tool is freely rotatable or applies a torque in the unwinding direction to the drive shaft (10); to pull the tensioning strap (5) off the winding drum (7), a rotary tool is connected to the coupling profile (12), and an axial force is applied to the drive shaft (10) by means of the rotary tool, whereby the fastening means (6) is pulled and wherein either the rotary tool is freely rotatable or applies a torque in the unwinding direction to the drive shaft (10); to wind the tensioning strap (5) onto the winding drum (7), a rotary tool is connected to the coupling profile (12), and an axial force is applied to the drive shaft (10) by means of the rotary tool, wherein the rotary tool applies a torque in the winding direction to the drive shaft (10).

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