Strip material conveying device

Abstract

The utility model relates to product packaging technical field especially relates to a kind of belt material conveying devices.The belt material conveying device includes frame, intermediate roll, two compression roller assemblies and two unwinding rollers;Intermediate roll is rotatably arranged on frame;Two compression roller assemblies are located at the two sides of intermediate roll respectively, and each compression roller assembly includes moving frame, compression driving part and compression roller, and compression roller is rotatably arranged on moving frame, and compression driving part is arranged on frame, and the output end of compression driving part is connected with moving frame, to drive compression roller to move towards the direction close to or away from intermediate roll by moving frame;Two unwinding rollers are set up one by one with two compression roller assemblies, and are rotatably arranged on frame, and the belt material to be conveyed wound on unwinding roller can be transported between intermediate roll and corresponding compression roller.The belt material conveying device can replace the effect of material roll on unwinding roller without stopping production line, to greatly improve production line efficiency and production line benefit.

Description

Technical Field

[0001] This utility model relates to the field of product packaging technology, and in particular to a material conveying device. Background Technology

[0002] A bagging machine for household appliances refers to an automated device that wraps household appliances in packaging bags. By wrapping household appliances in packaging bags, it can provide moisture-proof, waterproof, dust-proof, and pollution-proof effects. On the other hand, it can also absorb minor vibrations and impacts during logistics and transportation, reducing the impact of external forces on the internal components of the household appliances, and reducing the risk of internal structural loosening or failure due to bumps.

[0003] Bag-making machines in related technologies typically include a feeding device for conveying packaging bags to a preset position. This feeding device includes a frame and unwinding rollers, intermediate rollers, and pressure rollers, all rotatably mounted on the frame. Packaging bag rolls are wound on the unwinding rollers and pass between the intermediate and pressure rollers. The rotation of the intermediate and pressure rollers facilitates the conveying of the packaging bag rolls. However, when the packaging bag rolls on the unwinding rollers are exhausted, the entire packaging production line needs to be shut down to allow operators to replace them with new rolls. This process results in intermittent shutdowns, severely impacting production line efficiency and profitability.

[0004] Therefore, there is an urgent need for a material conveying device to solve the above problems. Utility Model Content

[0005] The purpose of this invention is to provide a material conveying device that enables the replacement of packaging bag rolls during production line operation, thereby significantly improving production line efficiency and effectiveness.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A conveyor belt device, comprising:

[0008] frame;

[0009] An intermediate roller is rotatably mounted on the frame;

[0010] Two pressure roller assemblies are located on both sides of the intermediate roller, and each pressure roller assembly includes a movable frame, a pressure drive, and a pressure roller. The pressure roller is rotatably mounted on the movable frame, and the pressure drive is mounted on the frame. The output end of the pressure drive is connected to the movable frame so as to drive the pressure roller to move towards or away from the intermediate roller through the movable frame.

[0011] Two unwinding rollers are arranged in a one-to-one correspondence with the two clamping roller assemblies, and both are rotatably mounted on the frame. The strip material to be conveyed wound on the unwinding rollers can be conveyed between the intermediate roller and the corresponding clamping roller.

[0012] As a preferred embodiment of the conveyor belt device provided by this utility model, the conveyor belt device further includes a position adjustment component. The frame includes a frame body and a mounting frame slidably disposed on the frame body. The intermediate roller and the pressure roller assembly are both mounted on the mounting frame. The position adjustment component is configured to drive the mounting frame to move along a first direction.

[0013] As a preferred embodiment of the conveyor belt device provided by this utility model, the position adjustment component includes:

[0014] Adjustment drive components are mounted on the frame.

[0015] A connector, the two ends of which are respectively connected to the output end of the adjustment drive and the mounting bracket, the adjustment drive driving the mounting bracket to move along a first direction through the connector.

[0016] As a preferred embodiment of the conveyor belt device provided by this utility model, the position adjustment component further includes a limiting member disposed on the frame, the limiting member being used to limit the maximum displacement of the connecting member.

[0017] As a preferred embodiment of the conveying device provided by this utility model, a first guide assembly is further provided between the frame and the mounting frame. The first guide assembly includes a first slider and a first slide rail that are slidably engaged. One of the first slider and the first slide rail is disposed on the frame, and the other is disposed on the mounting frame.

[0018] As a preferred embodiment of the conveyor belt device provided by this utility model, the number of the first sliders is at least two, and the at least two first sliders are distributed along the extension direction of the first slide rail, and both slide in contact with the first slide rail.

[0019] As a preferred embodiment of the conveying device provided by this utility model, each of the pressing roller assemblies includes two movable frames, and the two ends of each pressing roller are respectively rotatably connected to the two movable frames, and each movable frame corresponds to one pressing drive component.

[0020] As a preferred embodiment of the conveyor belt device provided by this utility model, the conveyor belt device further includes a second guide component corresponding to the movable frame. The second guide component includes a second slider and a second slide rail that are slidably engaged. One of the second slider and the second slide rail is disposed on the movable frame, and the other is disposed on the frame.

[0021] As a preferred embodiment of the conveyor belt device provided by this utility model, the conveyor belt device further includes a rotary drive assembly, which is disposed on the frame and its output end is connected to the intermediate roller to drive the intermediate roller to rotate.

[0022] Alternatively, the conveyor belt may further include a rotary drive assembly corresponding to each of the pressing rollers. The rotary drive assembly is mounted on the movable frame and its output end is connected to the corresponding pressing roller to drive the pressing roller to rotate.

[0023] As a preferred embodiment of the conveying device provided by this utility model, at least one tensioning roller is rotatably arranged between each of the pressing rollers and the intermediate rollers, and the conveying belt is sequentially wound around each of the tensioning rollers.

[0024] The beneficial effects of this utility model are:

[0025] The material conveying device provided by this utility model has two unwinding rollers and corresponding clamping roller assemblies. The clamping rollers of the two clamping roller assemblies can alternately cooperate with the intermediate roller to realize the conveying of the material to be conveyed on the corresponding unwinding roller. When the material to be conveyed on one of the unwinding rollers is conveyed, the operator can replace the material roll on the other unwinding roller, thereby realizing the function of changing the material roll on the unwinding roller without stopping the production line, so as to greatly improve the production line efficiency and production line benefits. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the conveyor belt device provided in this embodiment of the present invention from one perspective;

[0027] Figure 2 This is a schematic diagram of the material conveying device provided in this embodiment of the present invention from another perspective;

[0028] Figure 3 yes Figure 1 A magnified view of a portion at point A;

[0029] Figure 4 yes Figure 2 A magnified view of a section at point B.

[0030] In the picture:

[0031] 10. Frame; 11. Frame body; 12. Mounting bracket; 13. First guide assembly; 131. First slider; 132. First slide rail;

[0032] 20. Intermediate roller;

[0033] 30. Pressure roller assembly; 301. First pressure roller assembly; 302. Second pressure roller assembly; 31. Movable frame; 32. Pressure drive component; 33. Pressure roller;

[0034] 40. Position adjustment assembly; 41. Adjustment drive component; 42. Connecting component; 43. Limiting component;

[0035] 50. Unwinding roller; 51. First unwinding roller; 52. Second unwinding roller; 501. Belt material to be conveyed; 5011. First belt material; 5012. Second belt material;

[0036] 60. Second guide assembly; 61. Second slider; 62. Second slide rail;

[0037] 70. Rotary drive assembly;

[0038] 80. Tensioning roller. Detailed Implementation

[0039] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar parts or parts having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0040] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0041] In the description of this utility model, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] like Figures 1-4 As shown, this embodiment provides a conveying device for conveying materials, which includes a frame 10, an intermediate roller 20, two pressing roller assemblies 30, and two unwinding rollers 50. The intermediate roller 20 is rotatably mounted on the frame 10. The two pressing roller assemblies 30 are located on both sides of the intermediate roller 20. Each pressing roller assembly 30 includes a movable frame 31, a pressing drive 32, and a pressing roller 33. The pressing roller 33 is rotatably mounted on the movable frame 31. The pressing drive 32 is mounted on the frame 10, and its output end is connected to the movable frame 31 to drive the pressing roller 33 to move towards or away from the intermediate roller 20 via the movable frame 31. The two unwinding rollers 50 are arranged one-to-one with the two pressing roller assemblies 30 and are rotatably mounted on the frame 10. The conveying material 501 wound on the unwinding rollers 50 can be conveyed between the intermediate roller 20 and the corresponding pressing roller 33.

[0043] It should be noted that the conveyor belt in this embodiment is mainly used in a bagging machine to transport packaging bags to a preset station, thereby facilitating the bagging mechanism to wrap the packaging bags onto the products to be packaged. Specifically, the conveyor belt 501 in this embodiment refers to the packaging bag roll material. Of course, in other embodiments, this conveyor belt can also be applied to other production lines that require conveying conveyor belts to preset positions, and this embodiment does not limit this application.

[0044] To facilitate understanding of the working principle of this conveyor belt device, the following will be explained: Figure 1 The unwinding roller 50 located on the left side is defined as the first unwinding roller 51, and the conveyor belt 501 wound on the first unwinding roller 51 is the first conveyor belt 5011. Figure 1 The unwinding roller 50 located on the right side is defined as the second unwinding roller 52, and the conveying strip 501 wound on the second unwinding roller 52 is defined as the second material strip 5012; the pressure roller assembly 30 corresponding to the first unwinding roller 51 is defined as the first pressure roller assembly 301, and the pressure roller assembly 30 corresponding to the second unwinding roller 52 is defined as the second pressure roller assembly 302. Figure 1 , Figure 3 as well as Figure 4 As shown, the working principle of this conveyor belt device is as follows:

[0045] 1) The pressing drive 32 of the first pressing roller assembly 301 drives the pressing roller 33 to move away from the intermediate roller 20, and passes the end of the first material strip 5011 between the intermediate roller 20 and the corresponding pressing roller 33; the pressing drive 32 of the second pressing roller assembly 302 drives the pressing roller 33 to move away from the intermediate roller 20, and passes the end of the second material strip 5012 between the intermediate roller 20 and the corresponding pressing roller 33.

[0046] 2) The pressing drive 32 of the first pressing roller assembly 301 drives the pressing roller 33 to move closer to the intermediate roller 20 to press the first material strip 5011. The intermediate roller 20 and the pressing roller 33 rotate relative to each other, thereby realizing the conveying of the first material strip 5011 to the preset station.

[0047] 3) When the first strip 5011 wound on the first unwinding roller 51 is consumed, the pressing drive 32 of the first pressing roller assembly 301 drives the pressing roller 33 to move away from the intermediate roller 20. At the same time, the pressing drive 32 of the second pressing roller assembly 302 drives the pressing roller 33 to move closer to the intermediate roller 20. At this time, the intermediate roller 20 and the pressing roller 33 of the second pressing roller assembly 302 rotate relative to each other, which can realize the conveying of the second strip 5012, and the operator can replace the strip on the first unwinding roller 51.

[0048] 4) When the second strip 5012 wound on the second unwinding roller 52 is consumed, the pressing drive 32 of the second pressing roller assembly 302 drives the pressing roller 33 to move away from the intermediate roller 20. At the same time, the pressing drive 32 of the first pressing roller assembly 301 drives the pressing roller 33 to move closer to the intermediate roller 20. At this time, the intermediate roller 20 and the pressing roller 33 of the first pressing roller assembly 301 rotate relative to each other, which can realize the conveying of the first strip 5011, and the operator can replace the roll on the second unwinding roller 52.

[0049] 5) Repeat steps 3) to 4) above until the product packaging is complete.

[0050] The conveying device provided in this embodiment, by setting two unwinding rollers 50 and a pressure roller assembly 30 corresponding to each of the two unwinding rollers 50, allows the pressure rollers 33 of the two pressure roller assemblies 30 to alternately cooperate with the intermediate roller 20 to realize the conveying of the conveyed strip 501 on the corresponding unwinding roller 50. When the conveyed strip 501 on one of the unwinding rollers 50 is conveyed, the operator can replace the material roll on the other unwinding roller 50, thereby realizing the function of replacing the material roll on the unwinding roller 50 without stopping the production line, so as to greatly improve the production line efficiency and production line benefits.

[0051] In some embodiments, the clamping drive 32 is a clamping cylinder, which has advantages such as fast response speed, low maintenance cost, and high reliability. Of course, in other embodiments, the clamping drive 32 can also be other drive devices with linear drive function.

[0052] In some embodiments, at least one tensioning roller 80 is rotatably disposed between each pressing roller 33 and the intermediate roller 20, and the conveying belt 501 is sequentially wound around each tensioning roller 80. By setting the tensioning rollers 80, the tension of the conveying belt 501 can be stabilized so that it remains taut throughout the conveying process, avoiding deviation during the conveying process.

[0053] like Figure 3 and Figure 4 As shown, each pressing roller assembly 30 includes two movable frames 31, and the two ends of each pressing roller 33 are rotatably connected to the two movable frames 31 respectively, and each movable frame 31 corresponds to a pressing drive component 32. With this arrangement, it can be ensured that when the pressing roller 33 moves towards or away from the intermediate roller 20, the two ends of the pressing roller 33 can move synchronously, and when cooperating with the intermediate roller 20 to convey the conveyor belt 501, the pressing roller 33 can apply a uniform pressing force to the intermediate roller 20, thereby achieving smooth conveying of the conveyor belt 501.

[0054] Optionally, both ends of each pressing roller 33 are rotatably connected to the corresponding movable frame 31 via a first bearing to ensure the smoothness of the rotation process of the pressing roller 33.

[0055] In some embodiments, the conveyor belt further includes a second guide assembly 60 corresponding to the movable frame 31. The second guide assembly 60 is located between the frame 10 and the corresponding movable frame 31 to guide the movement of the movable frame 31 relative to the frame 10, thereby ensuring the stability and smoothness of the movement of the movable frame 31 relative to the frame 10, and reducing friction between the movable frame 31 and the frame 10 during relative movement, reducing wear, and thus extending the service life of the conveyor belt.

[0056] For example, the second guide assembly 60 includes a second slider 61 and a second slide rail 62 that slide in a sliding engagement. The second slider 61 is disposed on the movable frame 31, and the second slide rail 62 is disposed on the frame 10. The structure is simple and easy to process and assemble. Of course, in other embodiments, the second slider 61 can also be disposed on the frame 10, and the second slide rail 62 can be disposed on the movable frame 31, which can achieve the same effect.

[0057] like Figure 2 and Figure 4 As shown, the conveyor belt also includes a rotary drive assembly 70, which is mounted on the frame 10 and its output end is connected to the intermediate roller 20 to drive the intermediate roller 20 to rotate. When the intermediate roller 20 rotates, the clamping roller 33, which is pressed against the intermediate roller 20, can rotate synchronously, thereby realizing the conveying of the conveyor belt 501. At this time, the intermediate roller 20 acts as the drive roller, and the clamping roller 33 acts as the driven roller.

[0058] Of course, in other embodiments, the number of rotary drive components 70 can also be set to two, corresponding one-to-one with the pressure rollers 33. The rotary drive components 70 are mounted on the movable frame 31, and their output ends are connected to the corresponding pressure rollers 33 to drive the pressure rollers 33 to rotate. This design can also achieve the above-mentioned effect. In this case, the pressure rollers 33 act as drive rollers, and the intermediate rollers 20 act as driven rollers. It can be understood that when the intermediate rollers 20 act as drive rollers, one rotary drive component 70 can be omitted to simplify the structure of the conveyor belt and reduce processing costs.

[0059] In some embodiments, the rotary drive assembly 70 is a rotary motor, which has the advantages of simple and reliable structure, low maintenance cost, and fast start-stop response.

[0060] like Figure 1 and Figure 3 As shown, the conveyor belt also includes a position adjustment component 40. The frame 10 includes a frame body 11 and a mounting frame 12 slidably mounted on the frame body 11. The intermediate roller 20 and the pressure roller assembly 30 are both mounted on the mounting frame 12. The position adjustment component 40 is configured to drive the mounting frame 12 to move along a first direction. Specifically, the first direction refers to the arrangement direction of the intermediate roller 20 and the two pressure rollers 33. When the roll of material on one of the unwinding rollers 50 is consumed and before the other unwinding roller 50 begins to be conveyed, the position adjustment component 40 can drive the intermediate roller 20 and the two pressure roller assemblies 30 to move synchronously along the first direction by a preset distance through the mounting frame 12, so that the conveyor belt 501 is always conveyed at the same position, thereby ensuring the stability of the conveying process of the conveyor belt 501.

[0061] Specifically, the position adjustment assembly 40 includes an adjustment drive 41 and a connector 42. The adjustment drive 41 is mounted on the frame 11. The two ends of the connector 42 are respectively connected to the output end of the adjustment drive 41 and the mounting frame 12. The adjustment drive 41 drives the mounting frame 12 to move along a first direction through the connector 42. This arrangement facilitates the installation of the position adjustment assembly 40 and ensures a stable connection between the position adjustment assembly 40 and the mounting frame 12.

[0062] In some embodiments, the adjusting drive 41 is a clamping cylinder, which has advantages such as fast response speed, low maintenance cost, and high reliability. Of course, in other embodiments, the adjusting drive 41 can also be other drive devices with linear drive function.

[0063] In some embodiments, the position adjustment assembly 40 further includes a limiting member 43 disposed on the frame 11, which limits the maximum displacement of the connecting member 42. Specifically, when the position adjustment assembly 40 drives the mounting frame 12 to move to the left until the connecting member 42 abuts against the limiting member 43, the unwinding roller 50 (second unwinding roller 52) on the right is in a preset transmission position, that is, the second strip 5012 begins to be conveyed; when the position adjustment assembly 40 drives the mounting frame 12 to move to the right to the initial position of the output end of the adjustment drive member 41, the unwinding roller 50 (first unwinding roller 51) on the left is in a preset transmission position, that is, the first strip 5011 begins to be conveyed. Exemplarily, the limiting member 43 is a rubber block, which has a good buffering effect and avoids hard collision between the connecting member 42 and the limiting member 43, which could cause damage to one of them.

[0064] In some embodiments, a first guide component 13 is also provided between the frame 11 and the mounting frame 12. The first guide component 13 is used to guide the movement of the mounting frame 12 relative to the frame 11, thereby ensuring the stability and smoothness of the movement of the mounting frame 12 relative to the frame 11, and reducing friction between the frame 11 and the mounting frame 12 during relative movement, reducing wear, and thus extending the service life of the conveyor belt.

[0065] For example, the first guide assembly 13 includes a first slider 131 and a first slide rail 132 that slide in a sliding fit. The first slider 131 is disposed on the mounting bracket 12, and the first slide rail 132 is disposed on the frame 11. The structure is simple and easy to process and assemble. Of course, in other embodiments, the first slider 131 can also be disposed on the frame 11, and the first slide rail 132 can be disposed on the mounting bracket 12, which can achieve the same effect.

[0066] Optionally, the number of first sliders 131 is at least two. At least two first sliders 131 are arranged sequentially along the extension direction of the first slide rail 132 and are slidably engaged with the first slide rail 132. This reduces the material used in the first sliders 131 while ensuring the stability of the relative sliding between the two, thereby reducing material costs.

[0067] In some embodiments, there are two mounting brackets 12, which are located at both ends of the intermediate roller 20 in the axial direction. The two ends of the intermediate roller 20 are rotatably connected to the mounting brackets 12 on the corresponding sides through second bearings to ensure the smoothness of the rotation process of the intermediate roller 20.

[0068] In some embodiments, such as Figure 3 and Figure 4 As shown, the position adjustment component 40 and the rotary drive component 70 are located at both ends of the axial direction of the intermediate roller 20 to improve space utilization and ensure the structural compactness of the entire conveyor belt.

[0069] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A conveyor belt system, characterized in that, include: Rack (10); An intermediate roller (20) is rotatably mounted on the frame (10); Two pressure roller assemblies (30) are located on both sides of the intermediate roller (20). Each pressure roller assembly (30) includes a movable frame (31), a pressure drive (32), and a pressure roller (33). The pressure roller (33) is rotatably mounted on the movable frame (31). The pressure drive (32) is mounted on the frame (10), and the output end of the pressure drive (32) is connected to the movable frame (31) so as to drive the pressure roller (33) to move closer to or further away from the intermediate roller (20) through the movable frame (31). Two unwinding rollers (50) are arranged in a one-to-one correspondence with the two pressing roller assemblies (30), and both are rotatably mounted on the frame (10). The strip material (501) to be conveyed wound on the unwinding rollers (50) can be conveyed between the intermediate roller (20) and the corresponding pressing roller (33).

2. The conveyor belt device according to claim 1, characterized in that, The conveyor belt also includes a position adjustment component (40). The frame (10) includes a frame (11) and a mounting frame (12) slidably disposed on the frame (11). The intermediate roller (20) and the pressure roller assembly (30) are both mounted on the mounting frame (12). The position adjustment component (40) is configured to drive the mounting frame (12) to move along a first direction.

3. The conveyor belt device according to claim 2, characterized in that, The position adjustment component (40) includes: Adjustment drive (41) is provided on the frame (11); The connector (42) has two ends connected to the output end of the adjustment drive (41) and the mounting bracket (12), respectively. The adjustment drive (41) drives the mounting bracket (12) to move along the first direction through the connector (42).

4. The conveyor belt device according to claim 3, characterized in that, The position adjustment assembly (40) also includes a limiting member (43) disposed on the frame (11), the limiting member (43) being used to limit the maximum displacement of the connector (42).

5. The conveyor belt device according to claim 2, characterized in that, A first guide assembly (13) is also provided between the frame (11) and the mounting bracket (12). The first guide assembly (13) includes a first slider (131) and a first slide rail (132) that slide in a sliding fit. One of the first slider (131) and the first slide rail (132) is provided on the frame (11), and the other is provided on the mounting bracket (12).

6. The conveyor belt device according to claim 5, characterized in that, The number of the first slider (131) is at least two, and the at least two first sliders (131) are distributed along the extension direction of the first slide rail (132) and are slidably engaged with the first slide rail (132).

7. The conveyor belt device according to claim 1, characterized in that, Each of the pressing roller assemblies (30) includes two moving frames (31), with each pressing roller (33) having its two ends rotatably connected to the two moving frames (31), and each moving frame (31) corresponding to one pressing drive (32).

8. The conveyor belt device according to claim 1, characterized in that, The conveying device further includes a second guide component (60) corresponding to the moving frame (31). The second guide component (60) includes a second slider (61) and a second slide rail (62) that are slidably engaged. One of the second slider (61) and the second slide rail (62) is disposed on the moving frame (31), and the other is disposed on the frame (10).

9. The conveyor belt device according to claim 1, characterized in that, The conveyor belt also includes a rotary drive assembly (70), which is mounted on the frame (10) and its output end is connected to the intermediate roller (20) to drive the intermediate roller (20) to rotate. Alternatively, the conveying device may further include a rotary drive assembly (70) corresponding to each of the pressing rollers (33). The rotary drive assembly (70) is mounted on the movable frame (31) and its output end is connected to the corresponding pressing roller (33) to drive the pressing roller (33) to rotate.

10. The belt conveyor according to any one of claims 1 to 9, characterized in that, At least one tensioning roller (80) is rotatably disposed between each of the pressing rollers (33) and the intermediate roller (20), and the conveying strip (501) is sequentially wound around each of the tensioning rollers (80).

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