Dynamic tensioning system for circulating traction device

Abstract

The invention relates to a tensioning system for an endless traction device, comprising an actuator and a first deflection element, the actuator interacting with the first deflection element, and the actuator enabling the first deflection element to be arranged relative to the endless traction device in order to vary the pretension of the endless traction device. According to the invention, the tensioning system has a second deflection element, the second deflection element is engaged with the circulating traction device, and the second deflection element interacts with the first deflection element and the circulating traction device in the manner of a pulley block.

Description

Technical Field

[0001] The invention relates to a dynamic tensioning system for an endless (endless) traction device according to the preamble of independent claim 1 . Background Art

[0002] Such a dynamic tensioning system for an endless traction device comprises an actuator and a first steering element, wherein the actuator cooperates with the first steering element and wherein the actuator enables the first steering element to be set (adjusted) relative to the endless traction device in order to change the pretensioning of the endless traction device.

[0003] Endless traction systems are used to transmit rotational drive forces, in particular when a certain distance needs to be overcome between a drive element and an output element. Various types of cables, chains and belts can be used as endless traction devices and thus for force transmission. Depending on the application scenario and the scope of use, endless traction systems require tensioning devices in order to keep the pulling force required for force transmission between the endless traction device and the drive disc (traction sheave) within the relevant (determinative / standard) operating range or to set it to a predefined value.

[0004] In particular, in the case of high loads and high precision requirements, the required preload needs to be dynamically maintained throughout the traction system to prevent the endless traction device from slipping or jumping out of the drive disc. As the length of the endless traction system increases, the requirements on the tensioning system also increase. In order to ensure the required preload, the actuator for tensioning is often required to have a longer travel distance or often needs to use multiple actuators, which increases the complexity of the tensioning system.

[0005] DE 100 13 340 A1 already discloses a dynamic tensioning system according to the preamble of independent claim 1. A belt grinder is described, the grinding belt of which is designed as an endless traction device, wherein the belt tension is regulated and adjusted by means of an actuator so that a predefined contact force is applied as constantly as possible to the contact roller.

[0006] However, the tensioning system described is not optimally suited for the use of long, endless traction devices, the pretensioning of which requires dynamic adjustment. On the one hand, when using long, endless traction devices, the travel distance of the tensioning system required to maintain the required pretensioning is increased, which in turn hinders dynamic adjustment. On the other hand, the longer travel distance leads to a greater installation space requirement for the actuator. Summary of the invention

[0007] In order to overcome the above-mentioned drawbacks, the object of the present invention is to provide a dynamic tensioning system for an endless traction device, which improves the dynamics of the clamping force adjustment while the actuator size remains unchanged.

[0008] This object is achieved by the features of independent claim 1 .

[0009] Accordingly, the object is achieved according to the invention in that the tensioning system has a second deflection element, wherein the second deflection element engages with the endless traction device and wherein the second deflection element is arranged to interact with the first deflection element and with the endless traction device in the manner of a pulley block.

[0010] Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0011] According to an advantageous embodiment of the invention, the first deflection element comprises a first roller and a second roller, wherein the first roller and the second roller are arranged such that the endless traction device is deflected successively by the two rollers. A particularly simple and compact construction can be achieved if the two rollers are arranged substantially parallel to one another, i.e. planes lying in the normal direction of the respective rotational axis extend substantially parallel to one another. In the case of this arrangement, substantially parallel means that the value of the angle between the two planes does not exceed 10°, advantageously does not exceed 5°, and particularly advantageously within the usual position tolerances when the two rollers are aligned with one another.

[0012] A simple and compact design can also be achieved if the rotation axes of the two rollers are oriented substantially coaxially to one another. In this embodiment, substantially coaxial means that the planes extend substantially parallel to one another in the normal direction of the rotation axes and that the rotation axes are embodied at a distance from one another that is not greater than the width of one roller, preferably not greater than half the width of one roller, and particularly preferably the distance of the axes of the two rollers from one another does not exceed the usual tolerances when mounting the rollers.

[0013] In view of the simple and compact construction of the first deflection element, it is advantageous if the first roller and the second roller have the same dimensions. However, it is also conceivable that the two rollers have different diameters despite the same width, or that the two rollers have equal diameters despite different widths. However, preferably, the two rollers have the same technical dimensions and differ only in production-related deviations.

[0014] However, in some applications, it is also conceivable that the two rollers are at an angle relative to each other, that is, their axes of rotation are implemented as non-coaxial. In the case of poor installation space ratios, or in order to achieve better guidance of the circulating traction device, this can be arranged.

[0015] According to a further advantageous embodiment of the invention, the second deflecting element comprises a third roller.

[0016] According to a particularly advantageous embodiment of the invention, the second deflection element is arranged so that the endless traction device is deflected by the second deflection element between the deflection by the first roller and the second roller. Accordingly, the first deflection element and the second deflection element act together in the manner of a pulley block, wherein one of the two deflection elements forms the movable roller (non-fixed roller) required for the pulley block, while the corresponding other deflection element forms the fixed roller. The third roller can be arranged essentially parallel to the first roller and the second roller, but in order to ensure the pulley block principle, the third roller or the axis of rotation of the third roller is in any case arranged at a distance from the axis of rotation of the roller(s) of the first deflection element. It is conceivable that the third roller is oriented non-parallel to the first two rollers. However, preferably, a plane in the normal direction of the axis of rotation of the third roller and extending through the center of the third roller is located between the first roller and the second roller, or intersects one of the two rollers.

[0017] According to another advantageous embodiment of the invention, the first roller has a first guide and the second roller has a second guide to prevent the endless traction device from coming into contact with itself. Of course, the third roller can also have a guide. The guide can be, for example, in the form of a circumferential depression or groove in the circumferential direction of the rollers, in order to prevent the endless traction device from sliding off one roller on the one hand and to prevent the endless traction device from coming into contact with itself on the other hand. However, in principle, any other conceivable configuration of the guide known from the prior art can also be used. Preferably, the two rollers can rotate independently of each other.

[0018] According to a particularly advantageous embodiment of the invention, the actuator comprises a (pneumatic) cylinder and a piston rod. However, in principle, any type of actuator can be used which is suitable for applying the necessary travel distance and the necessary force in order to move the first deflection element relative to the endless traction device and thereby pretension the endless traction device.

[0019] According to another particularly advantageous embodiment of the invention, the actuator comprises an adjustable hydraulic cylinder. The piston rod can engage directly with the first steering element, thereby transmitting the movement of the piston rod directly to the steering element. Of course, it is also conceivable that the piston rod and the first steering element act together kinematically and convert the force and movement of the piston rod. For example, the travel distance and the force exerted by the piston rod on the first steering element and thus on the endless traction device can be adjusted by a hydraulic system. It is clear that the actuator can also comprise a pneumatic cylinder, and then a pneumatic system is required to adjust the force and travel distance.

[0020] According to another advantageous embodiment of the invention, the first deflection element cooperates with the actuator so that the first deflection element moves in the working direction of the actuator in order to change the pretensioning (force) of the circulating traction device. In other words, the first deflection element preferably moves along the movement of the piston rod in the direction toward the circulating traction device or moves away from the circulating traction device in order to change the pretensioning (force) of the circulating traction device. By aligning the deflection element used as a pulley block and coordinating with the circulating traction device, although an increased force is required to pretension the actuator due to the actuator compared to the tensioning device described in the prior art, the travel distance required for this is shortened, which is a subversion of the pulley block principle to a certain extent. This has the advantage that the dynamics of the pretensioning system are improved, especially when long circulating traction devices are used. At the same time, a shorter travel distance also means that less installation space is required for the design and construction of the pretensioning system.

[0021] According to the essence of the invention, the pulley principle can be arbitrarily modified or extended to shorten the travel distance of the actuator. Therefore, in order to further reduce the travel distance required for the pretensioning endless traction device, it is conceivable that the first deflection element also includes another roller and the second deflection element also includes another roller, so that another pair of fixed rollers and moving rollers (non-fixed rollers / floating rollers) is generated by means of another loop of the endless traction device.

[0022] Apart from the rotational freedom, the second deflection element can be designed to be fixed. However, it is also conceivable that the actuator is designed and the second deflection element cooperates with the actuator in such a way that the second deflection element is moved in the opposite direction to the first deflection element and thus also contributes to the pretensioning of the endless traction device. It is also conceivable that the first deflection element is designed to be fixed, i.e. represents a fixed roller (pulley) of a pulley block, while the second deflection element can be set (adjusted) relative to the endless traction device by the actuator in order to change the pretensioning of the endless traction device. In other words, the pretensioning (force) of the endless traction device will always change if the two deflection elements do not move in the same direction over the same displacement distance.

[0023] According to another advantageous embodiment of the invention, the second steering element is arranged in a line with the working direction of the actuator. In the sense of the construction of a pretensioning system that is as compact as possible, it is advantageous that the second steering element is arranged as close to the actuator as possible. The second steering element can be arranged fixedly and non-movably at the actuator, but the second steering element can also be fastened in other ways. As mentioned above, the second steering element can also be implemented so that it is moved by the actuator relative to the circulating traction device in order to change the pretensioning (force) of the circulating traction device. Preferably, in any case, the second steering element is aligned in a line with the working (operating) direction. This means that this line of the working direction intersects with the second steering element. However, for reasons of installation space, it may also be necessary to arrange the second steering element at a certain distance from this line of the working (operating) direction of the actuator.

[0024] According to an advantageous embodiment of the invention, the tensioning system is designed for an endless traction device implemented as a steel cable. However, the dynamic tensioning system according to the invention can also be used without problems for belts, chains, bands or other endless traction devices known from the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] An embodiment according to the present invention is further explained below with reference to the accompanying drawings.

[0026] For the following embodiments, the same components are denoted by the same reference numerals. As long as a figure contains a reference numeral without a more detailed explanation of this reference numeral in the corresponding figure description, reference is made to the preceding or following figure description.

[0027] Figure 1a A schematic diagram showing the interaction between the dynamic tensioning system and the cyclic traction device according to the present invention is shown,

[0028] Figure 1b Show Figure 1a A side view of

[0029] Figure 2 An embodiment of the dynamic tensioning system according to the invention is shown. DETAILED DESCRIPTION

[0030] Figure 1aThe interaction of a dynamic tensioning system 1 according to the invention with an endless traction device 2 is schematically shown. The endless traction device 2 is guided and held in position by two lower tensioning rollers shown in the figure and a first deflection element 4 assigned to the dynamic tensioning system 1, one of which is implemented as a drive roller. The dynamic tensioning system 1 comprises an actuator 3, which in the present embodiment has a cylinder 11 and a piston rod 12, wherein the cylinder 11 is implemented as a hydraulic cylinder 13. The actuator 3 can be adjusted by a hydraulic adjustment system (not shown). The first deflection element 4 is arranged at the piston 12 of the actuator 3 and can thus be moved directly by the actuator 3. The working direction 14 is indicated by an arrow. The first deflection element 4 can also be set (adjusted) relative to the endless traction device 2 in this direction, thereby increasing or reducing the pretensioning (force) of the endless traction device 2. It can be seen that the second deflection element 5 is fastened to the actuator and, like the first deflection element 4, is aligned (in a straight line) with the working direction 14 of the actuator.

[0031] Overview Figure 1a and Figure 1b as well as Figure 2 , which show an embodiment of a dynamic tensioning system 1 designed according to the invention, it can also be seen that in the embodiment shown, the first deflection element 4 comprises two rollers (rollers) 6, 7, which are designed to be of equal size and whose rotation axes 15, 16 are oriented coaxially with respect to each other. In addition, the first roller 6 and the second roller 7 can rotate independently of each other. The third roller 8 is arranged so that its rotation axis 17 is designed to be parallel to and at a certain distance from the rotation axes 15, 16 of the first roller 6 and the second roller 7. In addition, the center plane of the third roller 8, which is oriented in the normal direction of the rotation axis 17, extends between the first two rollers 6, 7. Figure 1b It is easy to see the guides 9 , 10 of the first roller 6 and the second roller 7 , which are also designed as circumferential grooves, wherein the guide of the third roller 8 is also designed in the same way.

[0032] exist Figure 1b In the figure, the endless traction device 2 can be a steel cable, which is indicated by a dotted line, wherein the arrows indicate the movement direction of the corresponding trunnion of the endless traction device 2. It should be noted that the endless traction device 2 can also be moved in the other direction in principle, wherein all arrows point in the opposite direction. The endless traction device 2 consists of Figure 1aThe tensioning roller at the bottom right is diverted to the dynamic tensioning system 1. Within the dynamic tensioning system 1, the endless traction device 2 is diverted from the first roller 6 to the third roller 8 and from the third roller 8 to the second roller 7. Due to this special arrangement, the three rollers 6, 7, 8 act together as a pulley block, wherein the first deflection element 4, which includes the first roller 6 and the second roller 7, forms a so-called "moving roller" (unfixed roller / roller), and wherein the second deflection element 5, which includes the third roller 8, forms a fixed roller (fixed wheel). If the endless traction device 2 is now to be pre-tensioned more strongly by means of the actuator 3, the piston rod 12 and the first deflection element 4 with its aid in Figure 1a Compared to conventional tensioning systems without the second deflection element 5, which cooperates with the first deflection element 4 in the form of a pulley block, only half the travel distance of the piston rod 12 is required for the same change in pretension (force), wherein, of course, the actuator must exert a correspondingly greater force.

[0033] Figure 1a It is also shown that the enveloping angle α of the second roller 7 is less than 90°. However, it is also possible that the angle is exactly 90° and the enveloping angles of the first roller 6 and the second roller 7 are each 90°, so that the individual strands are oriented aligned relative to each other during feeding (infeeding) and when guided away from the tensioning system 1.

[0034] List of reference numerals:

[0035] 1 Tensioning system

[0036] 2 Circulation traction device

[0037] 3 Actuator

[0038] 4 First steering element

[0039] 5 Second steering element

[0040] 6 First Roll

[0041] 7 Second Roller

[0042] 8 Third Roller

[0043] 9 First guide part

[0044] 10 Second guide section

[0045] 11 cylinders

[0046] 12 Piston rod

[0047] 13 Hydraulic cylinder

[0048] 14 Work Direction

[0049] 15 Axis of rotation of first roller

[0050] 16 Rotation axis of the second roller

[0051] 17 Axis of rotation of the third roller

[0052] α The enclosing angle.

Claims

1. A tensioning system (1) for a circulating traction device (2), comprising an actuator (3) and a first steering element (4), wherein: The actuator (3) acts together with the first steering element (4), and wherein the actuator (3) enables the first steering element (4) to be arranged relative to the endless traction device (2) so as to change the pretensioning of the endless traction device (2), characterized in that the tensioning system (1) has a second steering element (5), wherein the second steering element (5) is engaged with the endless traction device (2), and wherein the second steering element (5) is arranged to act together with the first steering element (4) and the endless traction device (2) in the manner of a pulley set.

2. The tensioning system (1) according to claim 1, characterized in that The first deflection element (4) comprises a first roller (6) and a second roller (7), wherein the first roller (6) and the second roller (7) are arranged such that the endless traction device (2) is deflected successively by the two rollers (6, 7).

3. The tensioning system (1) according to claim 1 or 2, characterized in that The second deflecting element (5) comprises a third roller (8).

4. The tensioning system (1) according to claim 2 or 3, characterized in that The second deflection element (5) is arranged in such a way that the endless traction device (2) is deflected by the second deflection element (5) between deflection by the first roller (6) and the second roller (7).

5. The tensioning system (1) according to any one of claims 1 to 4, characterized in that The first roller (6) has a first guide (9) and the second roller (7) has a second guide (10) to prevent the endless traction device (2) from contacting itself.

6. The tensioning system (1) according to any one of claims 1 to 5, characterized in that The actuator (3) comprises a cylinder (11) and a piston rod (12).

7. The tensioning system (1) according to claim 6, characterized in that The actuator (3) comprises an adjustable hydraulic cylinder (13).

8. The tensioning system (1) according to any one of claims 1 to 7, characterized in that The first steering element (4) cooperates with the actuator (3) to move the first steering element (4) along the working direction of the actuator (3) so as to change the pretensioning of the endless traction device (2).

9. The tensioning system (1) according to any one of claims 1 to 8, characterized in that The second steering element (5) is arranged in a line with the working direction (14) of the actuator (3).

10. The tensioning system (1) according to any one of claims 2 to 9, characterized in that The first roller (6) and the second roller (7) each have an axis of rotation, wherein the axes of rotation are oriented substantially coaxially with respect to one another.

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