DE29503083U1 - Tensioner - Google Patents

Description

Utility model application
of Mr Udo Dolezych

Tensioning device

The invention relates to a tensioning device for tensioning the ends of a tensioning strap for packages that are looped into a two-sided self-clamping buckle, with a tensioning ratchet designed to wind up a strap end to be tensioned with a slotted shaft and with an automatic clamping device that counteracts the tensioning force to hold the strap in place, and with a double-function lever as an actuating element that is operatively connected to means for driving the slotted shaft when pivoted in the direction of the buckle, and to means for opening the clamping device and for cutting off the strap end emerging from the buckle when pivoted in the opposite direction, the lever having a base body mounted on the slotted shaft and interacting with a rotary lock, and an extension piece designed with a handle.

Tensioning devices of the type mentioned above have long been in use in many areas of the economy and are used to tension straps on packages. A strap end that can be wound up using the slotted shaft for tensioning using the hand lever can, in extreme cases, apply a tensioning force of between 600 and 1000 daN due to a lever transmission ratio with a slotted shaft radius of approx. 15 mm and an operating lever length of approx. 300 mm, i.e. 1:20. In a considerable number of cases, this would lead to damage to packages and packaged goods due to inadmissible pressure if the packaging staff were careless.

Based on this, the invention is based on the object of providing a clamping device as in the preamble of claim

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1 mentioned type in order to prevent the specified clamping forces from being exceeded within the limits of easy adjustability using uncomplicated, preferably retrofittable means, and this regardless of the changing "day's form" and/or physical constitution of the packers that are coming off.

The solution to the stated problem is achieved with the invention in a clamping device of the type mentioned at the beginning in that a joint is arranged between the base body and the extension piece and this has an overload protection device or is designed as such.

By arranging a joint designed as an overload protection device, an effective protection against exceeding specified tension values on the tensioning strap when strapping or binding packages with the tensioning device is implemented in an uncomplicated manner, in particular also retrofittable to existing devices. One design provides that the overload protection device is designed with means for limiting the permissible lever force that can be applied.

For this purpose, the invention advantageously further provides that the joint is designed to be bendable when the permissible leverage is reached or exceeded and has means for producing a clearly audible cracking sound.

Further embodiments are provided in accordance with the subclaims.

The invention is shown in drawings in an exemplary embodiment, from which further advantages and features of the invention can be seen.

— 3 The drawings show in detail:

Figure 1 is a side view of the device when tightening a tensioning strap;

Figure 2 is a perspective view of the device; Figure 3 is a section through the joint arrangement in a plane intersecting the axis of the operating lever.

The tensioning device shown in Figure 1 is shown tensioning a tensioning strap (4) over any package (5). The two ends (2, 3) of the tensioning strap (4) are looped into a two-sided self-clamping buckle (1). The function of the commercially available buckle (1) is assumed to be known to the expert and is not explained further here. The end of the tensioning strap (3) is threaded into the driveable slotted shaft (20) of a tensioning ratchet arranged inside the device and is tensioned with a predetermined force when the double-function lever (22) is moved in the direction of arrow (A), increasing until the overload protection device responds, bends slightly and at the same time produces a clearly audible cracking sound. This is an unmistakable and unmistakable sign for the operator that the permissible tensioning force has been reached and that he must stop tensioning.

From the illustration in Figure 1 it can be seen that the tension at the end of the strap (3) with an estimated lever transmission ratio to the operating lever (22) of 1:20 and a correspondingly large force (A) can reach very high values, which can even lead to damage to the package (5).

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With appropriate ergonomic handling, uncontrolled force could result in strap forces of up to 1000 daN. This risk to people, package (5) and contents is eliminated with the invention by specifying a limit on the tension force.

The device pulling on the tape (4) at the end of the tape (3) in the direction of the arrow (31) grips the automatic clamping device (21) with counter-holding by the base plate (19). This clamping device (21) works according to a proven principle, whereby the clamping force increases the more pulling force the tape (4) exerts on the device.

The double-function lever (22) is arranged and designed in the device in such a way that when pivoted in direction (A) towards the buckle (1) it is operatively connected to means for driving the slotted shaft (20), and when pivoted in the opposite direction (B) it is operatively connected to means (28) for opening the clamping device (21) and for cutting off the end of the strap (3) with the aid of the rotary shears (32).

The lever (22) has a base body (23) mounted on the slotted shaft (20) and interacting with a rotary lock, and an extension piece (24) designed with a handle (25). In this known design concept of the tensioning device, the improvement by the invention consists in the fact that a joint (26) is arranged between the base body (23) and the extension piece (24) and that this has an overload protection device (30) or is designed as such.

The pivot pin (10) of the joint (26) is clearly visible in Figure 1. Its function as an overload protection device will be explained in more detail below using Figure 2.

Figure 2 shows the device in perspective, from which the individual functional elements are clearly visible. The tensioning device has a base plate (19) which serves on the one hand as a base plate and to guide the tape (4) and on the other hand as a clamping foot in conjunction with the clamping device. The slotted shaft (20) which can be driven with the lever (22) can also be seen, which from the given viewing direction can only be driven in an anti-clockwise direction and can rotate freely in the opposite direction. On the front there is also the rotary shear (32), which cuts off the excess tape end when the lever (22) is moved in the direction (B) towards the end of the tensioning process.

You can also see the double-function lever (22), which is made up of the base body (23) and an extension piece (24), between which the joint (26) with the overload protection device (30) is arranged. When the base body (23) is pivoted in direction (B) until the end of the stroke, the lever (28) with a small roller is pressed down and lifts the clamping device (21) from the base plate (19). The operating lever also has the handle (25). Figure 3 shows the joint (26) with the overload protection device (30) in an exemplary design. This includes the means (10 to 14) for limiting a permissible lever force (A) · These are designed to interact in such a way that the joint (26) which can be pivoted around the pivot pin (10) at a slight bending angle in the direction (A) is guided with the beveled sliding piece (12) to the counterpart (11) which is under axial pressure of the disc springs (13) against a high restoring force dependent on the spring pressure, namely when the permissible maximum load is reached

by applying force to the extension piece (24), the thrust of the springs (13) is overcome and the counterpart (11) is pushed back against the springs (13). The joint (26) is thus designed to be bendable when the permissible lever force (A) is reached or exceeded and, in a manner essential to the invention, has means for producing a clearly audible cracking sound. This can be produced, for example, in such a way that at the end of the bending movement the sliding piece (12) suddenly strikes the conically beveled end of the tubular intermediate piece (16) connected to the screw socket (15) of the base body (23), thereby producing the cracking sound.

The number (17) designates a soft elastic sealing ring in the area of the joint (26) which protects the joint (26) against environmental influences such as moisture and/or dirt.

For the load-dependent adjustment of the spring (13), an adjusting screw (14) with a hexagon socket is provided inside the intermediate piece (16), which can be screwed more or less deeply into an internal thread of the intermediate piece (16) and forms the counter bearing of the spring set (13). The intermediate piece (16) is screwed onto a screw socket (15) that is firmly and preferably integrally connected to the base body (23). In addition to the problem-free adjustment of the spring set (13), this has the further advantage that after adjustment with the adjusting element (14), the set load can no longer be manipulated without special effort.

The shown and explained design of the moment-dependent joint (26) for overload protection is only one of the possible structural solutions. Other designs

forms should also fall under the invention, provided they make use of its basic features.

For example, the overload protection (30) can be arranged between the base body and the hand lever of a ratchet for tightening lashing straps. However, the measure can also be used that the tensioning device is a ratchet for tightening lashing straps.

With the design according to the invention, the clamping device optimally fulfills the task set out at the beginning.

buckle 25. Handle End of tape 26. Joint List of reference symbols End of tape 27. 1. tape 28. Lever 2. Package 29. 3. 30. Overload protection 4. 31. Arrow 5. 32. Rotary shears 6. 7. Pivot pin 8th. Counterpart 9. Sliding piece 10. Disc springs 11. Actuator 12. Screw socket 13. Intermediate piece 14. Sealing ring 15. 16. Base plate 17. Slotted shaft 18. Clamping device 19. Dual function lever 20. Base body 21. Extension piece 22. 23. 24.

Claims (10)

• · Tensioning device REQUIREMENTS 1. Tensioning device for tensioning a tensioning strap (4), in particular for packages, with a tensioning ratchet designed to wind up a strap end (3) to be tensioned with a driveable slotted shaft (20) and an automatic clamping device (21) that counteracts the tensioning force to hold the strap (4) in place, and with a double-function lever (22) as an actuating element, which, when pivoted in the direction of the buckle (1), is operatively connected to means for driving the slotted shaft (20), and when pivoted in the opposite direction to means for opening the clamping device (21) and for cutting off the strap end (3) emerging from the buckle (1), the lever (22) having a base body (23) mounted on the slotted shaft (20) and interacting with a rotary lock, and an extension piece (24) designed with a handle (25), characterized in that a joint (26) is arranged between the base body (23) and the extension piece (24) and this has an overload protection device (30) or is designed as such. 2. Tensioning device according to claim 1, characterized in that the overload protection device (30) is designed with means (10 to 14) for limiting a permissible lever force (A) that can be applied. 2 - 3. Tensioning device according to claim 1 or 2, characterized in that the joint (26) is designed to be bendable when a permissible lever force (A) is reached or exceeded and has means for producing a clearly audible cracking sound. 4. Tensioning device according to one of claims 1 to 3, characterized in that the joint (26) is equipped with a load limiting spring (13) which supports it flexibly and is designed with an adjustable restoring force. 5. Clamping device according to claim 4, characterized in that an adjusting screw (14) designed with a hexagon socket is provided for adjusting the force of the spring (13). 6. Tensioning device according to one or more of claims 1 to 5, characterized in that the overload protection (30) is designed to be activated during a pivoting movement of the lever (22) or the handle (25) on the extension (24) in the direction (A) against the buckle (1). 7. Clamping device according to one or more of claims 1 to 6, characterized in that the overload protection (30) is designed to be flexible when a force is applied to the handle (25) and generates a predetermined torque with the extension piece (24) on the joint (26). 8. Clamping device according to one or more of claims 1 to 7, characterized in that the joint (26) is designed to be sealable to the outside with a soft elastic sealing ring (17). 9. Tensioning device according to one of the preceding claims, characterized in that the overload protection (30) is arranged between the base body and the hand lever of a ratchet for lashing lashing straps. 10. Tensioning device according to one of claims 1 to 8, characterized in that it is a ratchet for tensioning lashing straps.