ELASTIC TRAINING MEANS AND METHOD FOR PRODUCING THE SAME

Description

[0001] The invention relates to an elastic traction means comprising at least one belt body and at least one tension carrier embedded in the belt body, in which the at least one tension carrier is arranged in the belt body running in the longitudinal direction of the traction means, and in which the belt body has at least one recess.

[0002] Such traction devices are usually made of polymeric compounds or rubber-based material blends with elastic properties. They are typically used to transmit drive forces along non-linear paths or to perform transport or conveying tasks. Power transmission in such a traction device is primarily achieved by means of embedded tension members, such as cords made of steel, aramid, polyamide, polyester, or carbon. These tension members extend longitudinally within the belt body of the traction device.

[0003] DE 10 2013 104 764 A1 discloses a method for manufacturing an elastic tension member configured as a belt with tension members embedded in a belt body. This document lists various polymer materials from which such tension members can be constructed, as well as various material designs for tension members that can be embedded therein.

[0004] The production of such traction elements is usually carried out in a rotary vulcanization device. Such rotary vulcanization devices are described, for example, in DE 1 931 972 A, DE 26 55 025 C2, and DE 10 2013 102 148 A1. Accordingly, to produce an elastic traction element, a base material is first extruded. During extrusion, the tension members flow into the extruded, still warm and relatively viscous material in an outlet nozzle. The resulting, still viscous material with the tension members is formed into the finished traction element between a belt and a cylindrical forming wheel, with heat being removed, with the belt wrapping around the forming wheel under pressure at a certain wrap angle. In the case of a toothed belt, the forming wheel has a corresponding toothing that is embossed into the belt body.If necessary, a fabric can be placed on the forming wheel in an intermediate step to further reinforce the traction element, for example in the tooth area.

[0005] For elastic traction devices intended for conveying tasks, it is often necessary to attach carriers, such as carrier lugs or carrier cleats, to the belt body of the traction device to carry a product. The carriers are often mechanically attached to the belt body, and they must not be wider than the belt body itself. This makes it necessary to reduce the width and / or thickness of the belt body at the appropriate points by creating cutouts. The cutouts are usually created by subsequent mechanical processing of the traction device, for example, by punching.

[0006] However, when a traction element is subsequently machined to create the aforementioned recesses, it frequently happens that the tension members running in the belt body in the area of the recesses to be created are severed. As a result, the tension members in question lose their functionality. As has been shown, this can lead to a significant reduction in the overall tensile strength and thus to a reduction in the tensile load capacity of the traction element. A subsequent machining step to create recesses after the actual completion of the traction element in a rotational vulcanization device also results in increased manufacturing costs.

[0007] DE 10 2012 009 980 A1 discloses an elastic traction device constructed as a cam belt made of a fabric-reinforced polymer, to whose outer surface functional elements for conveying tasks are riveted. The riveted joints each have a large-area support element on the inside of the belt, which is embedded in the cam belt through mechanical material removal or during vulcanization. The rivets are inserted through aligned through holes in the belt, support element, and functional element.

[0008] DE 10 2013 112 274 B4 shows an elastic traction element designed as a conveyor belt with a fabric insert and several cleats. The cleats are connected to the fabric insert via U-shaped connecting elements, with legs of the connecting elements penetrating the conveyor belt.

[0009] DE 10 2006 022011 B3 shows a traction device and a method for producing a traction device according to the preamble of claims 1 and 12, respectively.

[0010] Against this background, the invention is based on the object of presenting an elastic tension member with embedded tension members and recesses formed in the tension member, which has improved tensile strength and can be manufactured more cost-effectively than known technical solutions. Furthermore, a method for producing such a tension member is to be described.

[0011] The solution to this problem results from the features of the independent claims, while advantageous embodiments and further developments of the invention can be found in the respective associated subclaims.

[0012] The invention is based on the finding that in an elastic traction device, its tension members, which are embedded as strength members in the longitudinal direction of the traction device, are crucial for the level of tensile forces that can be transmitted. Furthermore, it is evident that recesses in the traction device, which are introduced into the previously vulcanized traction device, can locally damage or even destroy individual tension members in the belt body. Furthermore, it is easy to understand that additional processing steps on a traction device already manufactured in an extrusion process result in additional manufacturing costs. Tensile members that are damaged by the introduction of recesses in the belt body lose their functionality as force transmitters in the traction device. Tensile devices whose tension members all remain intact during production and processing of the traction device, on the other hand, have a higher load-bearing capacity.In particular, an improved traction device, the tension members of which are all intact, can transport goods which may exert high tensile forces on the traction device reliably and without the risk of tearing or permanent overloading of the traction device.

[0013] The invention is therefore initially based on a traction device comprising at least one belt body and at least one tension carrier embedded in the belt body, in which the at least one tension carrier is arranged in the belt body running in the longitudinal direction of the traction device, and in which the belt body has at least one recess. To achieve the stated object with regard to the creation of a traction device, the invention provides that the at least one tension carrier is arranged in the belt body in such a way that none of the tension carriers is severed by the at least one recess.

[0014] To clarify the term, it should be noted that a tensile member is a flexible fiber or thread product that is elongated in relation to its diameter and is used to absorb tensile forces.

[0015] Accordingly, the invention proposes an elastic traction device with tension members embedded in a belt body in the longitudinal direction of the traction device, which has recesses that, however, do not sever the tension members. This imparts improved tensile strength to the traction device compared to known generic traction devices, so that it is more resilient overall and, above all, can transmit higher tensile forces. The intactness of the tension members can also extend the service life of the traction device, thereby extending replacement intervals for these traction devices in machines and reducing service costs. The traction device according to the invention can be made of materials that have already proven themselves in conventional traction device production.

[0016] According to a preferred embodiment of the invention, it is provided that the tension members are designed as cords which, in the region of the at least one recess, are guided around the recess in a curved line such that they run at least predominantly at a distance from one another and from the edge of the recess.

[0017] A cord consists of several tensile strands, usually twisted together in a helix, each of which in turn consists of a multitude of individual fibers. Such tensile members have already proven themselves in numerous traction devices. They can consist of, for example, a glass cord, a polyethylene cord, a polyurethane cord, a carbon cord, and / or an aramid cord. The expert may specifically use suitable materials or combinations thereof to prioritize certain desired properties such as tensile strength, flexibility, aging resistance, acid resistance, and price-performance ratio, depending on the application and requirements.

[0018] Such tension members or cords can be guided gently, i.e. without kinks, around the recesses in the belt body of the traction device, whereby their course in the longitudinal direction of the traction device is largely maintained. This ensures that the cords in the traction device remain fully functional. The distances between all existing cords are largely maintained or at least reduced as little as possible, so that the elastic base material of the traction device completely surrounds the individual cords and occupies the space between adjacent cords. A local constriction of individual tension members in the area surrounding the recesses may result in a slight inhomogeneity in the density ratio of tension member material to base material in the affected areas of the belt body compared to the adjacent areas.However, this is considered to be of secondary importance compared to the considerable advantage of fully maintaining the capacity to absorb tensile forces in the areas concerned.

[0019] The invention allows for the formation of various recesses in the belt body. This allows the skilled person to adapt the proposed traction device to a wide variety of applications. According to the invention, the at least one recess is formed on a longitudinal end face of the belt body, so that the width of the traction device in the region of the recess is reduced accordingly to the geometry of the recess.

[0020] According to another embodiment of the invention, the thickness of the traction element in the region of the recess can be reduced by the depth of the recess. Of course, several recesses of the same or different configurations can also be combined on the belt body.

[0021] A broad area of application for the proposed traction device is in conveying tasks using the carrier devices already described above. According to the invention, the traction device has at least one carrier, which is inserted into the at least one recess and is non-positively connected to the belt body.

[0022] Accordingly, the traction device can be designed, for example, as a conveyor belt or conveyor belt for transporting goods. The required flights can be attached to the belt body in the designated recesses using proven connection techniques. For example, such flights can be press-fitted into corresponding recesses in the belt body. Likewise, clip connections of flights in the recesses of the belt body are possible. Material-to-material connections, such as adhesive or vulcanization techniques, are also possible. In the case of riveted or screwed connections for attaching flights in the recesses, it is advisable for the respective tension members to be routed further around the recesses to avoid damage.

[0023] Alternatively, the at least one recess can be designed for direct engagement and direct entrainment of a load. Accordingly, recesses on the belt body can also be provided without a driver for direct engagement and entrainment of a load. In this case, too, the traction device's capacity to absorb tensile forces is not limited by the recesses.

[0024] According to a special embodiment of the invention, it can be provided that the traction means has a plurality of belt bodies which are arranged parallel to one another, wherein at least one first pair of opposing recesses is formed on one of the belt bodies on its two longitudinal end faces, wherein at least one second pair of opposite end-face recesses is formed on the other of the two belt bodies on its two longitudinal end faces, and wherein the two belt bodies are connected to one another by at least one rod-shaped driver which is in positive engagement with the two opposite pairs of recesses.

[0025] Accordingly, in this embodiment of the traction device, at least two belt bodies are arranged parallel to one another. These belt bodies are connected to one another by a rod-shaped driver. For this purpose, the driver is firmly clamped into associated recesses in the belt body. Such a traction device can be provided, for example, in an opening and closing mechanism for a roller blind. The driver is moved along with the belt bodies of the traction device, depending on the application, possibly only linearly without deflection via a roller. The traction device is subjected to a tensile load, which is transmitted by tension carriers designed as cords. Because the tension carriers that run along the edges of the belt bodies in the longitudinal direction of the traction device are guided in an intact state around the recesses into which the driver is inserted, the traction device can absorb high tensile forces.

[0026] Furthermore, it can be provided that the at least one recess is formed at a free end of the belt body, wherein the recess is designed as a receptacle for a driver designed as a fastening means for securing the end of the traction means. Accordingly, recesses can also be provided for an end fastening of a traction means. Intact tension members at one end of the traction means help minimize the risk of a belt body secured at the end tearing off under high tensile load.

[0027] Furthermore, the traction means can be designed as a V-belt, a toothed belt, or a flat belt. These belts can be ring-shaped or have two free ends.

[0028] A special manufacturing process is necessary to produce a traction means according to the invention. The invention therefore also relates to a process for producing an elastic traction means having the features of at least one of the device claims, in which the belt body is produced from a rubber-elastic material in an extrusion process, in which at least one tension member is embedded in the belt body running in the longitudinal direction of the traction means, in which the belt body is given a desired geometry subsequently or simultaneously with the embedding, and in which at least one recess is created in the belt body on at least one longitudinal end face of the belt body. In this case, the at least one recess is created on the belt body during the geometry creation of the belt body, wherein none of the tension members in the belt body is severed.

[0029] When manufacturing the traction device according to the aforementioned method, the required recesses are created during the geometry design of the belt body. Depending on the arrangement and geometric configuration, the recesses are created using a suitable tool in a suitable machine. This eliminates a subsequent processing step, thus reducing the manufacturing costs of the traction device compared to known conventional manufacturing processes.

[0030] During the creation of the recesses, advantageously none of the tension members in the belt body are severed. This can be achieved and ensured by guiding those tension members whose path is directed toward the region of the recess during the creation of the at least one recess past the recess and embedding them in an intact state in the belt body outside the recess. 9 According to the invention, an associated driver is subsequently inserted into the at least one created recess in the belt body and is non-positively connected to the belt body.

[0031] This allows the traction device to be designed for a specific conveying task. Attaching the flight bars to the belt body prevents damage to the tension members, as the flight bars are inserted into the designated recesses, and the tension members were previously guided past these recesses during the manufacture of the traction device.

[0032] The invention will be explained in more detail below with reference to two embodiments shown in the accompanying drawing. Fig. 1 a plan view of a longitudinally cut section of a traction means with the features of the invention according to a first embodiment, Fig. 2 the traction device according to Fig. 1 in a perspective side view, and Fig. 3 a perspective view of a traction means according to a second embodiment of the invention.

[0033] Fig. 1shows a longitudinally sectioned section of a vulcanized elastic traction means 1 in the form of a V-belt. Due to the selected cutting plane, the wedge shape is not visible. The traction means 1 has a belt body 2 with a first recess 3 and a second recess 4, which are formed on a first longitudinal end face 5 and a second longitudinal end face 6 of the belt body 2, respectively, and are arranged opposite one another. The two recesses 3, 4 each have a trapezoidal geometry. Embedded in the belt body 2 are a first tension member 7a, a second tension member 7b, a third tension member 7c, and a fourth tension member 7d. The four tension members 7a, 7b, 7c, 7d are designed as cords that run in the longitudinal direction 30 of the traction means 1 and essentially parallel to one another, wherein they are spaced apart from one another.As a result, each tension member 7a, 7b, 7c, 7d is surrounded by an elastic base material of the tension means 1.

[0034] In area 8 of the recesses 3, 4, the arrangement of the four tension members 7a, 7b, 7c, 7d is somewhat narrowed towards the center of the belt body. The first tension member 7a, which is located on the outside towards the first longitudinal end face 5 and thus close to the recess, is guided in a curved line past the first recess 3. The fourth tension member 7d, which is located on the outside towards the second longitudinal end face 6 and thus close to the recess, is guided in a curved line past the second recess 4. The two second and third tension members 7b, 7c, which are located on the inside with respect to the recesses 3, 4, are guided in a less curved line, but are continuously spaced from each other and from their respective outer neighboring tension members 7a, 7d. All four tension members 7a, 7b, 7c, 7d are intact.In particular, the first tension member 7a is not severed by the first recess 3 adjacent to it and the fourth tension member 7d is not severed by the second recess 4 adjacent to it, whereby the tension means 1 has an exceptionally high tensile strength despite the recesses 3, 4.

[0035] The perspective representation in Fig. 2 shows a traction device 1' designed as a toothed belt, which, except for its teeth, has the same structure as the traction device 1 according to Fig. 1 . This traction element 1' clearly has a radially outer cover layer 9, which can be referred to as the belt back. Four tension members 7a, 7b, 7c, 7d embedded in the belt body 2 can be seen, as well as a substructure 10 of the traction element 1', which is formed radially inward relative to the cover layer 9.

[0036] The base 10 is provided with a tooth-shaped profile. Several teeth 11a, 11b, 11c, 11d, 11e, 11f and tooth bases 12a, 12b, 12c, 12d, 12e formed between these teeth can be seen. Fig. 2 In the exemplary section of the traction means 1' shown, a first tooth 11a, a first tooth base 12a, a second tooth 11b, a second tooth base 12b, a third tooth 11c, a third tooth base 12c, a fourth tooth 11d, a fourth tooth base 12d, a fifth tooth 11e, a fifth tooth base 12e and a sixth tooth 11f are shown alternately.

[0037] How Fig. 2further shows, the width 32 of the belt body 2 in the area 8 of the two recesses 3, 4 is correspondingly reduced in depth in the transverse direction 31 of the traction means 1'. The third and fourth tooth bases 12c, 12d, each partially arranged in this area 8, as well as the fourth tooth 11d, which is arranged entirely in this area 8, are correspondingly shortened in their contour by the two recesses 3, 4. To be precise, the fourth tooth 11d is narrower in width than the other teeth 11a, 11b, 11c, 11e, 11f shown. The depth of the recesses 3, 4 determines the remaining thickness 33 of the belt body 2. Thus, the recesses 3, 4 can penetrate the belt body 2 completely, as shown, or can each be designed as a depression.

[0038] Fig. 3 shows an embodiment with a traction means 1", which differs from the traction means 1, 1' according to Fig. 1 and Fig. 2is not formed with just one belt body 2 but with two belt bodies 13, 14. These belt bodies 13, 14 have a rectangular cross-sectional geometry. Embodiments with three or more belt bodies 13, 14 would also be possible. Accordingly, in the embodiment according to Fig. 3a first belt body 13 and a second belt body 14 with their longitudinal end faces 17, 18; 21, 22 arranged parallel to one another. The first belt body 13 has a third recess 15 and a fourth recess 16, which are formed on a third end face 17 and a fourth end face 18, respectively, and are arranged opposite one another. The third and fourth recesses 15, 16 each have a rectangular geometry. The second belt body 14 is constructed identically. It has a fifth recess 19 and a sixth recess 20, which are formed on a fifth end face 21 and a sixth end face 22 of the second belt body 14 and are arranged opposite one another. The fifth and sixth recesses 19, 20 also each have a rectangular geometry.

[0039] The third and fourth recesses 15, 16 of the first belt body 13 and the fifth and sixth recesses 19, 20 of the second belt body 14 are provided for receiving a common driver 23.

[0040] Fig. 3 shows the driver 23 in a state prepared for this purpose, but not yet inserted into the first and second belt bodies 13, 14. The driver 23 is designed as a rod by means of which the two belt bodies 13, 14 can be connected to one another. For this purpose, the driver 23 has at its first end 24 a first projection 25 and a second projection 26 for positively engaging in the associated third and fourth recesses 15, 16 of the first belt body 13, and at its second end 27 a third projection 28 and a fourth projection 29 for positively engaging in the associated fifth and sixth recesses 19, 20 of the second belt body 14.

[0041] The positive connection between the driver 23 and the two belt bodies 13, 14 can be achieved, for example, by means of a press fit, so that the driver 23 is firmly clamped in the assembled state and couples the two belt bodies 13, 14 to each other both in the longitudinal direction and in the transverse direction of the traction means 1''. The driver 23 can be provided for carrying a material not shown.

[0042] The belt bodies 2, 13, 14 according to the Figures 1 to 3are advantageously produced in an extrusion process. In this process, the four tension members 7a, 7b, 7c, 7d are embedded in the belt body 2, 13, 14 in the longitudinal direction 30 of the traction means 1, 1', 1". Subsequently or simultaneously, the first belt body 2, 13, 14 is given its profiling as a flat belt, V-belt or toothed belt. In this process, the two recesses 3, 4, 15, 16, 19, 20 of the respective belt body 2, 13, 14 are advantageously produced simultaneously. None of the four tension members 7a, 7b, 7c, 7d in the respective belt body 2, 13, 14 is severed in the process. The recesses 3, 4, 15, 16, 19, 20 are formed according to the Figures 1 to 3 shown exemplary arrangement and geometric design with a tool not described in detail here but suitable for this purpose in a machine suitable for this purpose. List of reference symbols

[0043] 1 Tension element, V-belt 1' Tension element, timing belt 1" Tension element, with two flat belts 2 Belt body 3 First recess 4 Second recess 5 First end face 6 Second end face 7a First tension member 7b Second tension member 7c Third tension member 7d Fourth tension member 8 Recess area 9 Cover layer 10 Substructure 11a First tooth 11b Second tooth 11c Third tooth 11d Fourth tooth 11e Fifth tooth 11f Sixth tooth 12a First tooth base 12b Second tooth base 12c Third tooth base 12d Fourth tooth base 12e Fifth tooth base 13 First belt body 14 Second belt body 15 Third recess 16 Fourth recess 17 Third end face 18 Fourth end face 19Fifth recess 20Sixth recess 21Fifth end face 22Sixth end face 23Carrier 24First end of the carrier 25First projection on the carrier 26Second projection on the carrier 27Second end of the carrier 28Third projection on the carrier 29Fourth projection on the carrier 30Longitudinal direction of the traction device 31Transverse direction of the traction device 32Width of the traction device orBelt body 33Thickness of the belt body.

Claims

1. Elastic traction means (1, 1', 1"), comprising at least one belt body (2, 13, 14), and at least one tension member (7a, 7b, 7c, 7d) embedded in the belt body (2, 13, 14), in which the at least one tension member (7a, 7b, 7c, 7d) is disposed in the belt body (2, 13, 14) so as to extend in the longitudinal direction (30) of the traction means (1, 1', 1"), and in which the belt body (2, 13, 14) has at least one recess (3, 4, 15, 16, 19, 20), wherein the at least one tension member (7a, 7b, 7c, 7d) is disposed in the belt body (2, 13, 14) in such a manner that none of the tension members (7a, 7b, 7c, 7d) is severed by the at least one recess (3, 4, 15, 16, 19, 20), wherein the traction means (1, 1', 1") for entraining a material has at least one driver (23) which is inserted into the at least one recess (3, 4, 15, 16, 19, 20) and connected in a force-fitting manner to the belt body (2, 13, 14), characterized in that the at least one recess (3, 4, 15, 16, 19, 20) on at least one longitudinally oriented end side (5, 6, 17, 18, 21, 22) of the belt body (2, 13, 14) reduces the width (32), or the width (32) and the thickness (33), of the belt body (2, 13, 14) in the transverse direction (31) perpendicular to the longitudinal direction (30) and perpendicular to the thickness (33).

2. Traction means according to Claim 1, characterized in that the tension members (7a, 7b, 7c, 7d) are formed as cords which in the region of the at least one recess (3, 4, 15, 16, 19, 20) are guided in curved lines about the recess (3, 4, 15, 16, 19, 20) in such a way that they extend at least largely at a mutual spacing and at a spacing from the periphery of the recess (3, 4, 15, 16, 19, 20).

3. Traction means according to Claim 1 or 2, characterized in that the at least one recess (3, 4, 15, 16, 19, 20) on a longitudinally oriented end side (5, 6, 17, 18, 21, 22) of the belt body (2, 13, 14) is formed in such a way that the width (32) of the traction means (1, 1', 1") in the region of the recess (3, 4, 15, 16, 19, 20) is reduced so as to correspond to the geometry of the recess (3, 4, 15, 16, 19, 20).

4. Traction means according to one of Claims 1 to 3, characterized in that the thickness (33) of the traction means (1, 1', 1") in the region of the recess (3, 4, 15, 16, 19, 20) is reduced so as to correspond to the depth of the recess (3, 4, 15, 16, 19, 20).

5. Traction means according to one of Claims 1 to 4, characterized in that the traction means (1") has a plurality of belt bodies (13, 14) which are disposed so as to be mutually parallel, wherein at least one first pair of mutually opposite recesses (15, 16) is formed on one of the belt bodies (13, 14) on its two longitudinally oriented end sides (17, 18), wherein at least a second pair of recesses (19, 20), whose end faces are mutually opposite, is formed on the other of the two belt bodies (13, 14) on its two longitudinally oriented end sides (21, 22), and wherein the two belt bodies (13, 14) are connected to one another by at least one rod-shaped driver (23) which engages in a form-fitting manner with the two mutually opposite pairs of recesses (15, 16; 19, 20).

6. Traction means according to one of Claims 1 to 5, characterized in that the at least one recess (3, 4, 15, 16, 19, 20) is formed on a free end of the belt body (2, 13, 14), wherein the recess (3, 4, 15, 16, 19, 20) is designed as a receptacle for a driver (23) formed as a fastening means for fastening the end of the traction means.

7. Traction means according to one of Claims 1 to 5, characterized in that the traction means (1) is formed as a V-belt.

8. Traction means according to one of Claims 1 to 5, characterized in that the traction means (1') is formed as a timing belt.

9. Traction means according to one of Claims 1 to 5, characterized in that the traction means (1") is formed as a flat belt.

10. Traction means according to one of Claims 7 or 9, characterized in that the traction means (1, 1', 1") formed as a flat belt, a V-belt, or as a timing belt is of annular shape.

11. Traction means according to one of Claims 7 or 10, characterized in that the traction means (1, 1', 1") formed as a flat belt, a V-belt, or as a timing belt has two free ends.

12. Method for producing an elastic traction means (1, 1', 1") having the features of at least one of Claims 1 to 11, wherein the belt body (2, 13, 14) is produced from a rubber-elastic material by an extrusion method in which at least one tension member (7a, 7b, 7c, 7d) is embedded in the belt body (2, 13, 14) so as to extend in the longitudinal direction (30) of the traction means (1, 1', 1"), in which a desired geometry is imparted to the belt body (2, 13, 14) subsequently to or simultaneously with the embedding, and in which the at least one recess (3, 4, 15, 16, 19, 20) is already generated while imparting the geometry of the belt body (2, 13, 14), wherein none of the tension members (7a, 7b, 7c, 7d) is severed in the belt body (2, 13, 14), characterized in that at least one recess (3, 4, 15, 16, 19, 20) which reduces the width (32), or the width (32) and the thickness (33), of the belt body (2, 13, 14) in the transverse direction (31) perpendicular to the longitudinal direction (30) and perpendicular to the thickness (33) is generated in the belt body (2, 13, 14) on at least one longitudinally oriented end side (5, 6, 17, 18, 21, 22) of the belt body (2, 13, 14).

13. Method according to Claim 12, characterized in that, when generating the at least one recess (3, 4, 15, 16, 19, 20), those of the tension members (7a, 7b, 7c, 7d) whose profile is oriented towards the region (8) of the recess (3, 4, 15, 16, 19, 20) are guided past the recess (3, 4, 15, 16, 19, 20) and embedded into the belt body (2, 13, 14) in an intact state outside the recess (3, 4, 15, 16, 19, 20).

14. Method according to Claim 12 or 13, characterized in that subsequently an assigned driver (23) is inserted into the at least one recess (3, 4, 15, 16, 19, 20) generated in the belt body (2, 13, 14) and is connected to the belt body (2, 13, 14) in a force-fitting manner.