Roller guide shoe for an elevator car of an elevator installation
The roller guide shoe addresses the issue of unstable elevator car guidance by employing a retaining bracket and roller assembly with perpendicular rollers to stabilize elevator cars, ensuring smooth and comfortable operation with an emergency guide feature.
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- INVENTIO AG
- Filing Date
- 2024-11-29
- Publication Date
- 2026-06-03
AI Technical Summary
Existing elevator guide shoes fail to provide safe, reliable, and comfortable guidance for elevator cars, particularly in managing up and down movements, leading to potential sideways oscillations and inadequate passenger comfort.
A roller guide shoe with a retaining bracket and roller assembly is designed to securely mount on the elevator car, featuring free-rotating rollers that engage with a U-shaped guide channel, preventing sideways oscillations and ensuring smooth movement by using a combination of ride rollers and a larger guide roller, with perpendicular axes to stabilize the elevator car.
The roller guide shoe effectively guides the elevator car, reducing sideways oscillations and enhancing passenger comfort by providing stable, smooth, and reliable movement along guide rails, even in the event of roller damage, through an integrated emergency guide feature.
Smart Images
Figure IMGAF001_ABST
Abstract
Description
[0001] The invention relates to a roller guide shoe according to the preamble of claim 1. Furthermore, the invention relates to an elevator whose elevator car is equipped with such roller guide shoes.
[0002] Modern multi-floor buildings often require an elevator installation to transport people and goods between the different floors of the building. The elevator installation has an elevator car moving vertically up and down in an elevator shaft. The elevator car can be connected by means of carrying equipment, for example in the form of suspension cables or carrying straps, by means of an attachment drive unit in the vertical elevator shaft. In addition to the elevator car, the elevator system usually includes at least one counterweight, which is moved in opposite directions in the elevator shaft. To ensure that the elevator car is guided in a sufficiently precise linear manner, guide rails are used that are fixed in the elevator shaft. The elevator car and the counterweight run along the guide rails running longitudinally through the elevator shaft. A sliding or roller type guide shoes are usually used to guide elevator cars and counterweights. Usually, the guide shoes are locked to at least one surface of the guide rails. In addition to the guiding function, the guide surfaces of the guide rail also serve as engagement surfaces for safety devices, which are used to stop the elevator car.
[0003] The guide rail with a T-profile design has proven itself to a reliable and durable component for many years. However, guide rails are also known for guiding elevator car, which provide a U-shaped guide channel. Such a guide rail has become known, for example, from the WO 2020 / 127787 A1. Such guide rails contain a guided contours for both the elevator car and the counterweight in a single component. The guide contour for the elevator car is designed as a U-shaped guide channel. The elevator car may utilize multi-rollers guide shoes that are installed to match with groove-like guide channel of the elevator rail.
[0004] It is an objective of the present invention to avoid the disadvantages of the existing guide shoe and, in particular, to create a roller guide shoe that can safely and reliably manage up and down movement of an elevator car and deliver high degree of comfort to the passengers.
[0005] According to the invention, these and other problems are solved by means of a roller guide shoe according to the features of claim 1. The roller guide shoe is adapted to guide an elevator car used for moving passengers or goods along a guide rail extending in the direction of travel that may be a longitudinal direction. The guide rail has a U-shaped guide channel to accommodate the roller guide shoe rollers. The U-shaped guide channel can be used to form two lateral guide surfaces facing each other and a frontal guide surface connecting them wherein the lateral guide surfaces and the frontal guide surface define a "U" in the cross-section. The lateral guide surfaces are preferably connected at right angles to the frontal guide surface. The two opposite lateral guide surfaces can extend along a first direction to provide sufficient engagement surface to at least one of the rollers of the roller guide shoe. The two opposite lateral guide surfaces also lock the guide shoe rollers inside the U-shaped guide channel and prevent sideways oscillations of the elevator car. The cross-section of the frontal guide surface can be extended in a second direction and adapted to roughly fit a diameter of one of the rollers. The two directions, i.e., the first direction on one side and the second direction on the other, can be perpendicular to each other thus forming a rectangular "U".
[0006] The roller guide shoe of the invention comprises of two main modules namely, a retaining bracket and a roller assembly. The retaining bracket module is adapted to be securely mounted on a side structure of the elevator car. Thereafter, the roller assembly module is coupled to the retaining bracket such that the roller assembly is secured inserted between the retaining bracket and the U-shaped channel of the guide rail.
[0007] The retaining bracket of the roller guide shoe can be mounted on the elevator car structure using any of the known means of mechanical joint such as bolting, wielding, or riveting. By using a bolting means to couple retaining bracket and the elevator car, the retaining bracket can be installed or repaired or replaced after installation of elevator system. Furthermore, the retaining bracket comprises of a longitudinally elongated slot designed such that the roller assembly can be firmly inserted in the elongated slot during the assembly of roller guide shoe. The elongated slot of the retaining bracket can have a wider open end to allow easy insertion of the roller assembly into the elongated slot. The retaining bracket further comprise at least one outwards projected surface that can function as an emergency guide shoe. The integration of the emergency guide in the retaining bracket ensures that even if one or more rollers are omitted, for example as a result of bearing damage, a guiding function is maintained.
[0008] The roller assembly of the roller guide shoe comprises of a pair of free-rotating rollers mounted on a common axle, preferably spaced from each other along the axle. The pair of rollers are adapted to substantially cover the cross-sectional width of the frontal guide surface and ensure optimal front-facing guidance of the elevator car. The pair of rollers are adapted to guide the elevator car while running on the frontal guide surface of the U-shaped guide channel of the guide rail during elevator operation. For lateral guidance, the roller assembly comprises of a guide roller that is adapted to engage with either of the opposite lateral guide surfaces of the U-shaped guide channel. Preferably, the guide roller is oscillated between the lateral guide surfaces during the elevator car movement. This means that the guide roller does not contact both lateral guide surfaces at the same time. The rotational axis of the pair of rollers and the guide roller are perpendicular each other. The axis of rotation of the rollers can be in the first direction mentioned above and the roller axis of the guide roller can run in the second direction mentioned above. For optimal guidance, it can be advantageous if outer diameter of the guide roller is at least 50% larger than outer diameter of each roller of the pair of rollers and preferably at least twice as large. It can also be advantageous if each roller of the pair of rollers are spaced so far apart from each other that they reach close to the outer diameter of the guide roller when seen in a vertical projection or projection given by the longitudinal direction.
[0009] According to an embodiment, the roller guide shoe is adapted for guiding an elevator car of an elevator installation along a longitudinally extending guide rail comprising a guide channel. The roller guide shoe comprises of a retaining bracket having a longitudinally elongated slot wherein the elongated slot has an opening at one edge of the retaining bracket. Further, the roller guide shoe comprises a roller assembly having at least two ride rollers and a guide roller mounted on a supporting body wherein the ride rollers and the guide roller guide along the guide channel of the guide rails. Further, the supporting body of the roller assembly is adapted to be insertable or inserted in the elongated slot of the retaining bracket.
[0010] According to an embodiment, the roller guide shoe has the retaining bracket that is such that it is or can be removably coupled to a side structure of the elevator car and a first end of the supporting body is securely inserted in the elongated slot of the retaining bracket. A second end of the supporting body is securely coupled to the elevator car structure. In an embodiment, the second end of the supporting body is bolted to a side structure or roof structure of the elevator car. In another embodiment, the second end of the supporting body is securely coupled to the elevator car structure through a sheet metal spring clamp such that the sheet metal spring clamp exerts a force on the supporting body in the longitudinal direction of the elongated slot. After inserting the supporting body inside the elongated slot of the retaining bracket, the sheet metal spring provide enough force to firmly lock the supporting body withing elongated slot of the retaining bracket.
[0011] According to an embodiment, the elongated slot of the retaining bracket is wider at the opening end than at a closing end so as to allow easy insertion of the supporting body into the elongated slot.
[0012] According to an embodiment, the guide rail of the elevator installation has a U-shape guide channel. Further, the guide rail can have a smooth guide channel or a racked guide channel or a toothed guide channel.
[0013] According to an embodiment, roller assembly of the roller guide shoe comprises two ride rollers that are mounted on a common axis so as to be freely rotatable about a first axis of rotation for guiding along a frontal guide surface of the guide channel and the guide roller is mounted so as to be freely rotatable about a second axis of rotation for guiding along a lateral guide surface of the guide channel such that the second axis of rotation is perpendicular to the first axis of rotation.
[0014] According to an embodiment, the ride rollers and guide roller of the supporting body are mounted at a set distance apart where in the distance between mounting point of the two ride rollers and the mounting point of the guide roller is greater than a width of the supporting body.
[0015] According to an embodiment, the two ride rollers are mounted on the supporting body through a leaf spring wherein the leaf spring is adapted to isolate transfer of vibrations from the two ride rollers to the supporting body.
[0016] According to an embodiment, the retaining bracket has at least one rib extending into the guide channel to form an emergency guide shoe.
[0017] According to an embodiment, the roller assembly further comprises a combination of one or more shim plates and the supporting body that are inserted in the elongated slot to adjust the engagement between the two ride rollers and / or the guide roller with the guide channel.
[0018] According to an embodiment, the retaining bracket and / or the supporting body have a plate like structure.
[0019] According to an embodiment, the diameter of the guide roller is greater than width of the supporting body. Figure 1 is a highly simplified representation of a plan view of an elevator installation according to the invention with an elevator car equipped with roller guide shoes for guiding the elevator car along longitudinal guide rails, Figure 2 is a perspective representation of the elevator car with roller guide shoes installed, Figure 3 shows a top view of the roller guide shoe along with the guide rail having a U-shaped guide channel, Figure 4 shows perspective view of a roller guide shoe as per an embodiment of the invention, Figure 5 shows a perspective view of a roller guide shoe as per a second embodiment of the invention, Figure 6 shows an exploded view of the retaining bracket of the roller guide shoe from Figure 4, Figure 7 shows an exploded view of the roller assembly of the roller guide shoe from Figure 4,
[0020] Figure 1 illustrates a simplified plan view of an elevator installation 10, for a multi-storey building. The building has an elevator shaft 22 in which an elevator car 2 can move vertically up and down to individual floors to transport people or goods. The elevator installation of Figure 1 is designed as a traction elevator installation with at least one counterweight 23 that can be moved in the opposite direction to the elevator car 2. The elevator installation 10 shown here has two counterweights 23 as well as lifting equipment and drives (not shown). The two drives (e.g., traction sheave drives) drive the respective load-bearing devices (e.g., belts, steel cables) and thus move the elevator car 2 and the two opposing counterweights 23 in opposite directions. Each drive is assigned to one of the counterweights 23. To guide the vertical movement of the elevator car 2 and the counterweights 23 inside elevator shaft 22, two longitudinal extending guide rails 3 are provided on either side of elevator car 2. The elevator installation 10 shown in the present exemplary embodiment is characterized by special guide rails 3, which serve as a common guide for both elevator car 2 and the respective counterweights 23. Guide rails 3 can be manufactured as one-piece rolling profiles.
[0021] As per the Figure 1, the elevator car 2 has a front side 24 with a car door 27, a rear side 26 opposite to the front side and two side structures 25 connecting the front and rear to one another. The guide rails 3 are located on opposite sides of the elevator shaft 22 adjacent to the side structure 25. The guide rails 3 are fixed to the elevator shaft 22 by horizontal support structures fastened to the floor region at the front side of the elevator shaft. Each of the guide rail 3 comprises a U-shaped guide channel 11, in which a roller guide shoe 1 is used to guide the elevator car 2. The roller guide shoe 1 has two ride rollers 4, 5 for a frontal guide surface and a guide roller 6 for two lateral guide surfaces. The respective axes of rotation of ride rollers 4, 5 and guide roller 6 are designated R1 and R2. Details on the structure and functionality of roller guide shoe 1 can be found in Figures 4 to 7 below.
[0022] In Figure 1 it can also be seen that the respective counterweight 23 is guided along the guide rail 3 by means of guide arrangements. A safety device 20 is coupled to the elevator car 2 to restrict the car movement in case of emergency. However, safety device 20 could be an elevator car brake that can be secured during a car stop at a floor level. To brake elevator car 2, safety device 20 interacts with a rib-like protrusion 21 of guide rail 3.
[0023] Further details for elevator installation 10 and the guidance of elevator car 2 and counterweights 23 with common guide rails 3 can be found in WO 2020 / 127303 A1 and WO 2020 / 127787 A1.
[0024] Figure 2 illustrates a perspective view of the elevator car 2 of the elevator installation 10. The elevator car 2 is constructed like a cabin with two side structure 25 connecting a front entry point and a rear wall 26. In other installations, the elevator car 2 may also have a rear entry in addition to the front entry. Further, a sturdy flooring structure (not shown) provide a base to the cabin while being connected to both the side structures. The elevator car 2 is provided with a roof structure 16 that forms a canopy over the cabin. In the Figure 2, a side structure 25 of the elevator car 2 is shown to have two roller guide shoes A, B mounted at the top and bottom region respectively. The guide shoes A, B are shown to be mounted closure to the rear end of the car, however, they may be mounted in other sections of the side structure 25 based on the designed requirements of the elevator installation 10.
[0025] Figure 3 illustrates a top view of one of the guide rails 3 together with the roller guide shoe 1 installed according to an exemplary embodiment of the invention. The guide rail 3 has a special profile with a U-shaped guide channel 11 in which free rotating rollers of the roller guide shoe 1 are accommodated. The roller guide shoe 1 is fixed to side structure 25 of the elevator car 2. The roller guide shoe 1 has two ride rollers 4, 5 to engage with the frontal guide surface 28 of the U-shaped guide channel 11. The two ride rollers 4, 5 are mounted on a common axis to freely rotate while being engaged with the guide rail 3. The ride rollers guide the elevator car 2 during its vertical movement and essentially prevent lateral oscillations of the elevator car 2. The roller guide shoe 1 further includes a relatively larger guide roller 6 to engage with one of the lateral guide surfaces 18-1, 18-2 of the U-shaped guide channel 11. During the vertical movement of elevator car 2, the large guide roller 6 restricts the sidewise oscillations of the elevator car. After installation of the roller guide shoe, the guide roller 6 is positioned such that there are a few millimetres gap between the guide roller 6 and of the lateral guide surface 18-1, 18-2 of the guide channel 11. During a normal operations of elevator car, the guide roller 6 is adapted to oscillate between the two lateral guide surfaces 18-1, 18-2 such that guide roller 6 body does not contact both lateral guide surfaces at the same time.
[0026] Figure 4 represents a perspective view of an embodiment of a fully assembled roller guide shoe 1. The roller guide shoe 1 of the invention is construct from two main modules, a retaining bracket 7 and a roller assembly 9. The two modules are coupled together to form the roller guide shoe that can be mounted on the side structure of the elevator car 2. The retaining bracket 7 of the assembled roller guide shoe 1 is fabricated from sheet metal plate two nut-bolt fixtures 39 for mounting it to a side structure of the elevator car 2 and provide a firm mechanical joint with the car body. For other elevator cars, the retaining bracket 7 may be wielded or riveted to the elevator car structure. The mounting points 39 provides a secure and stiff mechanical coupled between retaining bracket 7 and the side structure 25 of the elevator car 2. The retaining bracket 7 further includes a longitudinally elongated slot 8 located at a first edge such that the elongated slot 8 has an open end 13 and a closed end. The shape and size of the elongated slot 8 is relative to a shape and size of the other module, a roller assembly 9. As described elsewhere, primary function of the roller guide shoe is to restrict car oscillation and provide a smooth ride to the passengers. The function can be achieved by fixing the retaining bracket 7 strongly with the elevator body ensuring the elevator car 2 and the roller guide shoe 1 travels in the same trajectory along the guide rails. The opposite edge to the first edge of the retaining bracket 7 comprises a lateral projection forming a rib that is wielded to the retaining bracket 7. The rib structure function an emergency guide shoe in a situation where a roller of the roller guide shoe 1 is damaged.
[0027] The other module of the roller guide shoe 1 is a roller assembly 9 comprising multiple free rotating rollers. After installation of the retaining bracket 7, the roller assembly 9 is inserted in the elongated slot 8 and can be easily removed for repair or replacement where required. A first end 32 of the roller assembly 8 is inserted in a gap between the guide channel 11 of the guide rail 3 and the elongated slot 8 of the retaining bracket 7. After the insertion, a second end 33 of the roller assembly 9 is fixed to the elevator car 2 using a bolt joint 21 thus preventing it from moving out of the elongated slot 8. The roller assembly 9 comprises two ride rollers 4, 5 mounted on a common axle and a single guide roller 6 mount on a separate axle. All the rollers are free rotating wheels capable of running at a similar speed as that of the elevator car 2. The ride roller 4, 5 rotate alone a first axis to engage with the frontal guide surface 28 of the U-shaped guide channel 11 of the guide rail 3. On the other hand, the guide roller 6 rotates alone a second axis to engage with the lateral guide surface 18-1, 18-2 for the guide channel 11. To get the best performance from the roller guide shoe 1, the first axis and second axis are perpendicular to each other. Lastly, the roller assembly can also have a few shim plates 19 inserted to adjust the engagement of the ride rollers 4, 5 and guide roller 6 with the U-shaped guide channel 11.
[0028] Figure 5 illustrate another embodiment of a roller guide shoe 1 comprising two major modules, a retaining bracket 7 and a roller assembly 9. In the figure 5, both the modules are combined to form the roller guide shoe 1. The roller guide shoe 1 comprises a retaining bracket 7 fabricated from a sheet metal plate securely fixed to the elevator car 2 body structure. In the figure 5, the retaining bracket 7 has multiple nut-bolt joints to strongly coupled it to the elevator car 2. On a first edge of the retaining bracket 7, there is an elongated slot 8 running to more than half the length of the retaining bracket 7. An edge opposite to the first edge comprises a projection rib that is formed by bending the lower edge of the retaining bracket 7. The projection is shaped like ribs 34 that forms an emergency guide shoe designed to guide the elevator car 2 in a situation where one of the guide shoe rollers is damaged or is completed lost from the roller assembly.
[0029] The other module of the roller guide shoe 1 is a roller assembly 9 comprising a pair of ride rollers 4, 5 and one relatively larger diameter guide roller 6. All the rollers are securely fixed firmly to a supporting body. The ride rollers are mounted on a common axle and are free to rotate. In the embodiment, the ride rollers 4, 5 axle is coupled to the roller assembly 9 using a leaf spring 35. The leaf spring isolates the vibrations happening at the rider roller 4,5 from reaching the elevator car body during normal operations. Further, the guide channel 11 of the guide rail 3 may have some undulation on its surface, in such situations the leaf spring 35 of the rider rollers, 4, 5 is adapted to provide continuous engagement with the frontal guide surface 28 of the guide channel 11. Thus, the leaf spring enhances the rider comfortable for the passengers. The roller assembly 9 further includes a larger diameter guide roller 6 mount below the rider rollers 4, 5. The guide roller 6 is free rotating wheel adapted to engage with one of the lateral guide surfaces 18-1, 18-2 of the U-shaped guide channel 11 of the guide rail 3.
[0030] To assemble the roller guide shoe 1, a first end 32 of the roller assembly 9 is inserted in open end 13 of the elongated slot 8 such that the ride rollers 4, 5 and guide roller 6 perfectly aligns with the U-shaped guide channel 11 of the guide rail 3. After inserting, a second end 33 of the roller assembly 9 is bolted to the roof structure of the elevator car 2 through a sheet metal spring clamp 17. Further, the second end 33 of the roller assembly 9 includes a small hoop 40 like structure on its first edge. The hook 40 provide a holding point for easy insertion and removal of the roller assemble during field installation.
[0031] Figure 6 represents an exploded view of the retaining bracket 7 of the roller guide shoe 1 in Figure 4. The retaining bracket 7 is shown as a sheet metal plate with two mounting points 39. The retaining bracket 7 can be fixed to the elevator car structure using two nut-bolt joints passing through the mounting points 39. Further, the retaining bracket 7 comprises an elongated slot 8 located in the middle section of the metal plate like structure. The elongated slot has an open end 13 located at the first edge of the retaining bracket 7 and close end on the opposite side. The edge opposite to the first edge comprises a rib like structure 34 that projects outwards. The rib structure 34 is made to be equivalent to the diameter of the guide roller 6. The rib structure 34 is adapted to function as an emergency guide shoes if the guide roller 6 is damaged. Further, the elongated slot 8 has a wider opening at its open end 13. During the installation of the roller guide shoe, the wider opening of the elongated slot 8 provides an easy insertion of roller assembly 9 and the taper closing section secures the roller assembly 9 perfectly in place.
[0032] Figure 7 represents an exploded view of the roller assembly 9 of the roller guide shoe 1 of Figure 4. The roller assembly 9 comprises of two ride rollers 4, 5 and a guide roller 9 mounted on a supporting body 12. As shown in the figure, the supporting body 12 is constructed using a sheet metal plate having mounting points 29 to fix the rider rollers 4, 5 and another mounting point 30 to fix the guide roller 6. The supporting body 12 further comprises a keyhole 21 that is utilized to securely bolt the roller assembly 9 with the elevator car structure. Further, the ride rollers 4, 5 are mounted on a common axis R1 and are adapted to freely rotate along their axis. The guide roller 6 is mount on a different axis R2 that is perpendicular to the rider rollers 4, 5 axis R1. Since the rotational axes of rider rollers and the guide roller are perpendicular to each other, therefore, the roller guide shoe 1 provides smooth guidance in a two-dimensional horizontal plane of the elevator car 2.
Claims
1. A roller guide shoe (1) for guiding an elevator car (2) of an elevator installation (10) along a longitudinally (z) extending guide rail (3) comprising a guide channel (11), the roller guide shoe (1) comprising: - a retaining bracket (7) having a longitudinally elongated slot (8), the elongated slot (8) having an open end (13) at one edge of the retaining bracket (7); and - a roller assembly (9) having at least two ride rollers (4, 5) and a guide roller (6) mounted on a supporting body (12) for guiding along the guide channel (11), wherein the supporting body (12) is insertable or inserted in the elongated slot (8) of the retaining bracket (7).
2. The roller guide shoe (1) according to claim 1, characterized in that the retaining bracket (7) is such that it can be removably coupled to a side wall (25) of the elevator car (2), a first end (32) of the supporting body (12) is securely inserted in the elongated slot (8) of the retaining bracket (7), and a second end (33) of the supporting body (12) is securely coupled to the elevator car (2).
3. The roller guide shoe (1) according to any of the preceding claims, characterized in that the second end (33) of the supporting body (12) is such that it can be securely coupled to the elevator car (2) through a sheet metal spring clamp (17) such that the sheet metal spring clamp (17) exerts a force on the supporting body (12) in the longitudinal direction of the elongated slot (8).
4. The roller guide shoe (1) according to any of the preceding claims, characterized in that the elongated slot (8) of the retaining bracket (7) is wider at the open end (13) than at a close end so as to allow easy insertion of the supporting body (12) into the elongated slot (8).
5. The roller guide shoe (1) according to any of the preceding claims, characterized in that the guide rail (3) has a U-shape guide channel (11).
6. The roller guide shoe (1) according to any of the preceding claims, characterized in that the guide rail (3) has a smooth guide channel or a racked guide channel or a toothed guide channel.
7. The roller guide shoe (1) according to any of the preceding claims, characterized in that the two ride rollers (4, 5) are mounted on a common axis so as to be freely rotatable about an axis of rotation (R1) for guiding along a frontal guide surface (28) of the guide channel (11), and the guide roller (6) is mounted so as to be freely rotatable about an axis of rotation (R2) for guiding along a side guide surface (18) of the guide channel (11), and the axis of rotation (R2) is perpendicular to the axis of rotation (R1).
8. The roller guide shoe (1) according to any of the preceding claims, characterized in that a distance between mounting point (29) of the two ride rollers (4, 5) and the mounting point (30) of the guide roller (6) is greater than a width of the supporting body (12).
9. The roller guide shoe (1) according to any of the preceding claims, characterized in that the two ride rollers (4, 5) are mounted on the supporting body (12) through a leaf spring (35) wherein the leaf spring (35) is adapted to isolate transfer of vibrations from the two ride rollers (4, 5) to the supporting body (12).
10. The roller guide shoe (1) according to any of the preceding claims, characterized in that the retaining bracket (7) has at least one rib structure (34) extending into the guide channel (11) to form an emergency guide shoe.
11. The roller guide shoe (1) according to any preceding claim, characterized that a combination of one or more shim plates (19) and the supporting body (12) are inserted in the elongated slot (8) to adjust the engagement between the two ride rollers (4, 5) and / or the guide roller (6) with the guide channel (11).
12. The roller guide shoe (1) according to any of the preceding claims, characterized in that the retaining bracket (7) and / or the supporting body (12) have a plate like structure.
13. The roller guide shoe (1) according to any of the preceding claims, characterized in that a diameter of the guide roller (6) is greater than width of the supporting body (12).