Double-steel-belt pressing machine

Abstract

The utility model discloses a double-steel-belt pressing machine, which relates to the technical field of processing equipment and comprises a rack, an upper steel belt, a lower steel belt and a fixed roller pressing mechanism, the upper steel belt is located above the lower steel belt, the upper steel belt and the lower steel belt are rotationally arranged on the rack, a plate gap is formed between the outer bottom face of the lower portion of the upper steel belt and the outer top face of the upper portion of the lower steel belt, and the advancing direction of a plate in the plate gap is the first direction; the fixed roller pressure applying mechanism comprises two roller groups which are symmetrically arranged; one roller group is arranged in a space enclosed by the upper steel belt, and the other roller group is arranged in a space enclosed by the lower steel belt; the roller set is provided with a plurality of rotating fixed rollers, the rotating axis of each fixed roller is perpendicular to the first direction, and each fixed roller is in rolling contact with the inner wall of the lower portion of the upper steel belt or the inner wall of the upper portion of the upper steel belt. And a far infrared lamp tube capable of radiating far infrared waves is fixedly arranged between every two adjacent fixed rollers. The plate temperature requirement can be rapidly met, and the plate machining effect is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of processing equipment, in particular to a double steel belt press. Background Art

[0002] The double steel belt press is a continuous press that uses two steel belts to work alternately and is used to press various plates and sheets. This press can provide greater pressure and faster speed, and the pressing time and pressure can be adjusted to meet different pressing needs. The double steel belt press has a wide range of uses. In addition to the man-made board industry, it can also be used to produce composite materials (fiber, metal, wood, plastic, etc.), flooring, melamine veneer, printed circuit boards, etc. As long as it is an industry that can be done by traditional flat presses, it can replace it.

[0003] At present, the temperature control of the pressed sheet in the common double steel belt press is mostly achieved by setting up a heat transfer oil channel and circulating heat transfer oil in the heat transfer oil channel. However, the preheating time of the heat transfer oil is relatively long, which has a certain impact on the pressing of the sheet, resulting in poor sheet processing effect. Utility Model Content

[0004] The purpose of the utility model is to provide a double steel belt press to solve the problems existing in the above-mentioned prior art, which can quickly meet the temperature requirements of the plate and improve the plate processing effect.

[0005] To achieve the above purpose, the utility model provides the following solutions:

[0006] The utility model provides a double steel belt press, comprising a frame, an upper steel belt, a lower steel belt and a fixed roller pressure mechanism; the upper steel belt is located above the lower steel belt, the upper steel belt and the lower steel belt are respectively rotatably arranged on the frame, a plate gap is formed between the lower outer bottom surface of the upper steel belt and the upper outer top surface of the lower steel belt, and the forward direction of the plate in the plate gap is a first direction; the fixed roller pressure mechanism comprises two symmetrically arranged roller groups; one roller group is arranged in the space enclosed by the upper steel belt, and the other roller group is arranged in the space enclosed by the lower steel belt; the roller group has a plurality of rotating fixed rollers, the rotation axis of each fixed roller is perpendicular to the first direction, and each fixed roller is respectively in rolling contact with the lower inner wall of the upper steel belt or the upper inner wall of the upper steel belt; a far-infrared lamp tube capable of radiating far-infrared waves is fixedly arranged between two adjacent fixed rollers.

[0007] Preferably, it also includes a chain blanket pressure mechanism, which includes two chain blanket rolling mechanisms that are symmetrical in upper and lower directions, one of the chain blanket rolling mechanisms is arranged in the space enclosed by the upper steel belt, and the other of the chain blanket rolling mechanisms is arranged in the space enclosed by the lower steel belt; in the first direction, each of the chain blanket rolling mechanisms is located at the rear side of the roller group; the chain blanket rolling mechanism has a rotating needle roller chain blanket and a pressure plate for pushing part of the needle roller chain blanket to press against the corresponding upper steel belt or the lower steel belt, and a first electric heating tube is buried in the pressure plate.

[0008] Preferably, it also includes a pressure plate pressing mechanism, which includes two pressure plate crimping mechanisms that are symmetrical in upper and lower directions, one of which is arranged in the space enclosed by the upper steel belt, and the other of which is arranged in the space enclosed by the lower steel belt; in the first direction, each of the pressure plate crimping mechanisms is located on the rear side of the roller group; the pressure plate crimping mechanism has a crimping plate that can move up and down, and a sliding pressure plate is fixedly provided on the side of the crimping plate away from the upper steel belt or the lower steel belt that is in pressure contact, and a second electric heating tube is buried in the sliding pressure plate.

[0009] Preferably, in the first direction, a rotating front steel belt traction roller is provided at the upper and lower positions of the front end of the frame, and a rotating rear steel belt traction roller is provided at the upper and lower positions of the rear end of the frame, the upper steel belt is sleeved on the upper front steel belt traction roller and the rear steel belt traction roller, and the lower steel belt is sleeved on the lower front steel belt traction roller and the rear steel belt traction roller; at least one of the front steel belt traction roller and the corresponding rear steel belt traction roller is transmission-connected with a driving mechanism.

[0010] Preferably, each of the fixed rollers has a circulation channel, and the circulation channel is used for circulating heat transfer oil.

[0011] Preferably, the roller group includes a first fixed frame, a plurality of first lifting mechanisms and a connecting plate, the first fixed frame is used to be fixedly connected to the frame, the fixed end of each of the first lifting mechanisms is used to be fixedly connected to the first fixed frame, and the telescopic end of each of the first lifting mechanisms is used to be fixedly connected to the connecting plate, the telescopic end of each of the first lifting mechanisms can drive the connecting plate to move toward or away from the corresponding upper steel belt or the lower steel belt, and a plurality of the fixed rollers are rotatably provided on a side of the connecting plate away from the first lifting mechanism, and the axis of the fixed roller coincides with the rotation axis of the fixed roller.

[0012] Compared with the prior art, the utility model has achieved the following technical effects:

[0013] The double steel belt press provided by the utility model adopts a far-infrared lamp tube arranged between two adjacent fixed rollers, and utilizes the far-infrared waves radiated by the far-infrared lamp tube to heat the two adjacent fixed rollers. It is electrically started and has a good heating effect. The radiation area can also cover the corresponding upper steel belt and lower steel belt to heat the covered area, and finally quickly meet the temperature requirements of the plate and improve the plate processing effect.

[0014] Furthermore, a first electric heating tube is buried inside the pressing plate in the chain blanket rolling mechanism to achieve the heating needs of the corresponding position, and the heating speed is fast, and the required temperature of the plate can be quickly reached.

[0015] Furthermore, a second electric heating tube is buried in the sliding pressing plate in the pressing plate pressure mechanism, and rapid heating is achieved by electric heating, which can quickly reach the temperature required for plate processing and ensure the heating temperature.

[0016] Furthermore, the entire press is formed by a frame and two front steel belt traction rollers and two rear steel belt traction rollers. The structure is simple, and the installation and fixation of each pressing mechanism is convenient, thereby ensuring the pressing effect.

[0017] Furthermore, a circulation channel is provided in the fixed roller, and the heating method of the heat transfer oil and the heating method of the radiant far-infrared wave are combined to complement each other, thereby achieving a rapid and stable heating effect on the plate at the fixed roller.

[0018] Furthermore, the first lifting mechanism is used to drive the fixed rollers on the connecting plate to squeeze the upper steel belt or the lower steel belt in the corresponding area, thereby adjusting the size of the gap between the plates. The structure is simple, stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 The overall structural diagram of the double steel belt press provided by the utility model;

[0021] Figure 2 A front view of the double steel belt press provided by the utility model;

[0022] Figure 3 This is a structural schematic diagram of a fixed roller pressure mechanism in a double steel belt press provided by the utility model;

[0023] Figure 4The utility model provides a schematic structural diagram of the pressure mechanism of the pressure plate in the double steel belt press.

[0024] In the picture: 100-Double steel belt press;

[0025] 10-frame; 11-upper steel belt; 12-lower steel belt; 13-plate gap; 14-front steel belt traction roller; 15-rear steel belt traction roller;

[0026] 20-fixed roller pressure mechanism; 21-first fixed frame; 22-first lifting mechanism; 23-connecting plate; 24-fixed roller; 25-far-infrared lamp;

[0027] 30-chain blanket pressure mechanism; 31-second fixed frame; 32-second lifting mechanism; 33-pressing plate; 34-needle chain blanket;

[0028] 40-pressing plate pressure mechanism; 41-third fixing frame; 42-third lifting mechanism; 43-sliding pressing plate; 431-heating plate; 432-wear-resistant plate; 44-second electric heating tube;

[0029] 50 - tensioning adjustment mechanism; 51 - first bracket; 52 - slider; 53 - telescopic cylinder. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] The utility model aims to provide a double steel belt press to solve the problems existing in the prior art, to quickly meet the temperature requirements of the plate and to improve the plate processing effect.

[0032] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0033] Embodiment 1

[0034] This embodiment provides a double steel belt press 100, such as Figure 1 to Figure 4As shown, it includes a frame 10, an upper steel belt 11, a lower steel belt 12 and a fixed roller pressure mechanism 20; the upper steel belt 11 is located above the lower steel belt 12, and the upper steel belt 11 and the lower steel belt 12 are respectively rotatably arranged on the frame 10, and a plate gap 13 is formed between the lower outer bottom surface of the upper steel belt 11 and the upper outer top surface of the lower steel belt 12, and the forward direction of the plate in the plate gap 13 is a first direction; the fixed roller pressure mechanism 20 includes two symmetrically arranged roller groups; one roller group is arranged in the space enclosed by the upper steel belt 11, and the other roller group is arranged in the space enclosed by the lower steel belt 12; the roller group has a plurality of rotating fixed rollers 24, and the rotation axis of each fixed roller 24 is perpendicular to the first direction, and each fixed roller 24 is in rolling contact with the lower inner wall of the upper steel belt 11 or the upper inner wall of the upper steel belt 11; a far-infrared lamp 25 capable of radiating far-infrared waves is fixedly provided between two adjacent fixed rollers 24.

[0035] A far-infrared lamp 25 is arranged between two adjacent fixed rollers 24, and the far-infrared waves radiated by the far-infrared lamp 25 are used to heat the two adjacent fixed rollers 24. The far-infrared lamp 25 is electrically started, and has a good heating effect. The radiation area can also cover the corresponding upper steel belt 11 and lower steel belt 12, thereby heating the covered area, and finally quickly meeting the temperature requirements of the plate and improving the plate processing effect.

[0036] The structure of the fixed roller pressure mechanism 20 is as follows:

[0037] Among the optional solutions of this embodiment, it is more preferred that Figure 1 to Figure 3 As shown, the roller group includes a first fixed frame 21, a plurality of first lifting mechanisms 22 and a connecting plate 23. The first fixed frame 21 is used to be fixedly connected to the frame 10. The fixed end of each first lifting mechanism 22 is used to be fixedly connected to the first fixed frame 21, and the telescopic end of each first lifting mechanism 22 is used to be fixedly connected to the connecting plate 23. The telescopic end of each first lifting mechanism 22 can drive the connecting plate 23 to move toward or away from the corresponding upper steel belt 11 or lower steel belt 12. A plurality of fixed rollers 24 are rotatably arranged on the side of the connecting plate 23 away from the first lifting mechanism 22, and the axis of the fixed roller 24 coincides with the rotation axis of the fixed roller 24. The first lifting mechanism 22 drives each fixed roller 24 on the connecting plate 23 to squeeze the upper steel belt 11 or lower steel belt 12 in the corresponding area, thereby adjusting the size of the plate gap 13. The structure is simple, stable and reliable.

[0038] In the optional scheme of this embodiment, it is more preferred that each fixed roller 24 has a circulation channel, and the circulation channel is used to circulate the heat transfer oil. The circulation channel is set in the fixed roller 24, and the heating method of the heat transfer oil and the heating method of the radiated far infrared wave complement each other to achieve a fast and stable heating effect on the plate at the fixed roller 24.

[0039] The structure of the chain carpet pressure mechanism 30 is as follows:

[0040] Among the optional solutions of this embodiment, it is more preferred that Figure 1 and Figure 2 As shown, the double steel belt press 100 also includes a chain blanket pressing mechanism 30, which includes two chain blanket rolling mechanisms symmetrical in the upper and lower directions, one of which is arranged in the space enclosed by the upper steel belt 11, and the other is arranged in the space enclosed by the lower steel belt 12; in the first direction, each chain blanket rolling mechanism is located at the rear side of the roller group; the chain blanket rolling mechanism has a rotating needle chain blanket 34 and a pressing plate 33 for pushing part of the needle chain blanket 34 to press against the corresponding upper steel belt 11 or lower steel belt 12, and a first electric heating tube is buried in the pressing plate 33. The pressing plate 33 in the chain blanket rolling mechanism adopts the method of burying the first electric heating tube to achieve the heating needs of the corresponding position, and its heating speed is fast, and the required temperature of the plate can be quickly reached.

[0041] Specifically, the chain blanket rolling mechanism includes a second fixed frame 31, a pressure plate 33, multiple second lifting mechanisms 32 and a needle chain blanket 34. The second fixed frame 31 is used to be fixedly connected to the frame 10. The pressure plate 33 is located below the second fixed frame 31. One end of each second lifting mechanism 32 is fixedly connected to the second fixed frame 31, and the telescopic end of each second lifting mechanism 32 is fixedly connected to the pressure plate 33. A driving sprocket is provided on both sides of the upper end of the second fixed frame 31 for rotation along the first direction, and a driven sprocket is provided at both ends of the pressure plate 33 for rotation along the second direction. The needle chain blanket 34 is sleeved on the outside of the two sets of driving sprockets and the two sets of driven sprockets.

[0042] Specifically, the driving sprocket is transmission-connected with a driver.

[0043] Specifically, the structure of the needle chain blanket 34 may be the same as the existing structure of the same type, and will not be described in detail here.

[0044] Specifically, a retractor may be provided on each set of driving sprockets on the second fixing frame 31 , and the retractor drives the driving sprockets to adjust the tension of the needle chain blanket 34 .

[0045] The structure of the pressing plate pressing mechanism 40 is as follows:

[0046] Among the optional solutions of this embodiment, it is more preferred that Figure 1 and Figure 2 and Figure 4As shown, the double steel belt press 100 also includes a platen pressing mechanism 40, which includes two platen crimping mechanisms that are symmetrical up and down, one platen crimping mechanism is arranged in the space enclosed by the upper steel belt 11, and the other platen crimping mechanism is arranged in the space enclosed by the lower steel belt 12; in the first direction, each platen crimping mechanism is located at the rear side of the roller group; the platen crimping mechanism has a crimping plate that can move up and down, and a sliding platen 43 is fixed on the side of the crimping plate that is away from the upper steel belt 11 or the lower steel belt 12, and a second electric heating tube 44 is buried in the sliding platen 43. The second electric heating tube 44 is buried in the sliding platen 43 in the platen pressing mechanism 40, and rapid heating is achieved by electric heating, which can quickly reach the temperature required for plate processing and ensure the heating temperature.

[0047] Specifically, the pressing plate crimping mechanism includes a third fixing frame 41, a third lifting mechanism 42 and a sliding pressing plate 43. The third fixing frame 41 is used to be fixedly connected to the frame 10. The third lifting mechanism 42 is fixedly arranged on the third fixing frame 41. The output end of the third lifting mechanism 42 is fixedly connected to the sliding pressing plate 43. The side of the sliding pressing plate 43 away from the third lifting mechanism 42 is used to be pressed against the inner wall of the upper steel strip 11 or the inner wall of the lower steel strip 12. The sliding pressing plate 43 directly contacts and extrude the corresponding inner wall of the upper steel strip 11 or the inner wall of the lower steel strip 12 by sliding friction, so as to adjust the degree of extrusion of the upper steel strip 11 and the lower steel strip 12. The structure is simple, stable and reliable.

[0048] Specifically, the sliding plate 43 includes a heating plate 431 and a wear-resistant plate 432 . A second electric heating tube 44 is embedded in the heating plate 431 . One side of the wear-resistant plate 432 is used for sliding friction with the inner wall of the upper steel belt 11 or the inner wall of the lower steel belt 12 .

[0049] Specifically, the second electric heating tube 44 can be a plurality of single straight tubes uniformly buried in the heating plate 431, or a curved tube uniformly coiled in the heating plate 431, or other existing arrangements that can achieve better heating effects.

[0050] The upper steel belt 11 and the lower steel belt 12 are installed on the frame 10:

[0051] Among the optional solutions of this embodiment, it is more preferred that Figure 1 and Figure 2As shown, in the first direction, a rotating front steel belt traction roller 14 is provided at the upper and lower positions of the front end of the frame 10, and a rotating rear steel belt traction roller 15 is provided at the upper and lower positions of the rear end of the frame 10. The upper steel belt 11 is sleeved on the upper front steel belt traction roller 14 and the rear steel belt traction roller 15, and the lower steel belt 12 is sleeved on the lower front steel belt traction roller 14 and the rear steel belt traction roller 15; at least one of the front steel belt traction roller 14 and the corresponding rear steel belt traction roller 15 is connected to a driving mechanism. The entire press is formed by the frame 10 and the two front steel belt traction rollers 14 and the two rear steel belt traction rollers 15, and its structure is simple, which is convenient for the installation and fixation of each pressing mechanism and ensures the pressing effect.

[0052] Specifically, the driving mechanism can drive the front steel belt traction roller 14 and the rear steel belt traction roller 15 to rotate, thereby driving the upper steel belt 11 or the lower steel belt 12 to rotate.

[0053] Specifically, when the front steel belt traction roller 14 and the corresponding rear steel belt traction roller 15 are both connected to the driving mechanism, dual drive is realized to drive the rotation of the upper steel belt 11 and the lower steel belt 12, and the rotation is more stable and reliable.

[0054] Specifically, a tensioning adjustment mechanism 50 may be further provided at the connection between the front steel belt traction roller 14 and the rear steel belt traction roller 15 and the frame 10 , so as to enable the front steel belt traction roller 14 and the corresponding rear steel belt traction roller 15 to adjust the tensioning degree of the upper steel belt 11 or the lower steel belt 12 .

[0055] Specifically, the tension adjustment mechanism 50 can be any structure that can achieve tension adjustment. Here, a specific method is used as an example to illustrate: Take the tension adjustment mechanism 50 of a front steel belt traction roller 14 as an example. Figure 1 As shown, the tensioning adjustment mechanism 50 includes a first bracket 51 and a second bracket, the first bracket 51 and the second bracket are respectively located at the two ends of the front steel belt traction roller 14, and the first bracket 51 and the second bracket are fixedly connected to the frame 10, the first bracket 51 and the second bracket are both provided with a slide groove, a slider 52 is slidably provided in the slide groove, the slider 52 can slide in the slide groove along the first direction, the two ends of the front steel belt traction roller 14 are respectively rotatably connected to the corresponding slider 52, and a telescopic cylinder 53 is fixedly provided at the position corresponding to the slider 52 on the frame 10, the telescopic end of the telescopic cylinder 53 is fixedly connected to the slider 52, and the telescopic end of the telescopic cylinder 53 can drive the slider 52 to move along the first direction.

[0056] The combination of the pressing mechanisms included in the double steel belt press 100:

[0057] Specifically, the pressure mechanism in the double steel belt press 100 may include a combination of a fixed roller pressure mechanism 20 and a chain blanket pressure mechanism 30, or a combination of a fixed roller pressure mechanism 20 and a pressure plate pressure mechanism 40, or a combination of a fixed roller pressure mechanism 20, a chain blanket pressure mechanism 30 and a pressure plate pressure mechanism 40 arranged in sequence, etc. It can also be a combination of the fixed roller pressure mechanism 20 and other existing pressure mechanisms.

[0058] Specifically, when the double steel belt press 100 includes three pressing mechanisms, the first pressing mechanism realizes pre-pressing and preheating, the second pressing mechanism realizes pressurization and heating, and the third pressing mechanism realizes pressure-maintaining and cooling.

[0059] Specifically, all the first lifting mechanisms 22, second lifting mechanisms 32, etc. having lifting functions can adopt lifting hydraulic cylinders.

[0060] The present invention uses specific examples to illustrate the principle and implementation of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A double steel belt press, characterized in that: It includes a frame, an upper steel belt, a lower steel belt and a fixed roller pressure mechanism; The upper steel belt is located above the lower steel belt, and the upper steel belt and the lower steel belt are rotatably arranged on the frame respectively, a plate gap is formed between the lower outer bottom surface of the upper steel belt and the upper outer top surface of the lower steel belt, and the advancing direction of the plate in the plate gap is a first direction; The fixed roller pressure mechanism comprises two symmetrically arranged roller groups; one roller group is arranged in the space enclosed by the upper steel belt, and the other roller group is arranged in the space enclosed by the lower steel belt; the roller group comprises a plurality of rotating fixed rollers, the rotation axis of each fixed roller is perpendicular to the first direction, and each fixed roller is in rolling contact with the lower inner wall of the upper steel belt or the upper inner wall of the upper steel belt respectively; A far-infrared lamp tube capable of radiating far-infrared waves is fixedly arranged between two adjacent fixed rollers.

2. The double steel belt press according to claim 1, characterized in that: It also includes a chain blanket pressing mechanism, which includes two chain blanket rolling mechanisms that are symmetrical in upper and lower directions, one of which is arranged in the space enclosed by the upper steel belt, and the other is arranged in the space enclosed by the lower steel belt; in the first direction, each of the chain blanket rolling mechanisms is located at the rear side of the roller group; The chain blanket rolling mechanism comprises a rotating needle roller chain blanket and a pressing plate for pushing a part of the needle roller chain blanket to press against the corresponding upper steel belt or the lower steel belt, and a first electric heating tube is embedded in the pressing plate.

3. The double steel belt press according to claim 1, characterized in that: It also includes a pressing plate pressing mechanism, the pressing plate pressing mechanism includes two pressing plate crimping mechanisms that are symmetrical in upper and lower directions, one of the pressing plate crimping mechanisms is arranged in the space enclosed by the upper steel belt, and the other of the pressing plate crimping mechanisms is arranged in the space enclosed by the lower steel belt; in the first direction, each of the pressing plate crimping mechanisms is located at the rear side of the roller group; The pressing plate crimping mechanism comprises a crimping plate which can move up and down, a sliding pressing plate is fixedly arranged on the side of the crimping plate away from the upper steel belt or the lower steel belt which is in press contact with the sliding pressing plate, and a second electric heating tube is embedded in the sliding pressing plate.

4. The double steel belt press according to claim 1, characterized in that: In the first direction, a rotating front steel belt traction roller is respectively provided at the upper and lower positions of the front end of the frame, and a rotating rear steel belt traction roller is respectively provided at the upper and lower positions of the rear end of the frame, the upper steel belt is sleeved on the upper front steel belt traction roller and the rear steel belt traction roller, and the lower steel belt is sleeved on the lower front steel belt traction roller and the rear steel belt traction roller; at least one of the front steel belt traction roller and the corresponding rear steel belt traction roller is transmission-connected with a driving mechanism.

5. The double steel belt press according to claim 1, characterized in that: Each of the fixed rollers has a circulation channel, and the circulation channel is used for circulating heat transfer oil.

6. The double steel belt press according to claim 1, characterized in that: The roller group includes a first fixed frame, a plurality of first lifting mechanisms and a connecting plate, the first fixed frame is used to be fixedly connected to the frame, the fixed end of each of the first lifting mechanisms is used to be fixedly connected to the first fixed frame, and the telescopic end of each of the first lifting mechanisms is used to be fixedly connected to the connecting plate, the telescopic end of each of the first lifting mechanisms can drive the connecting plate to move toward or away from the corresponding upper steel belt or the lower steel belt, and a plurality of the fixed rollers are rotatably provided on a side of the connecting plate away from the first lifting mechanism, and the axis of the fixed roller coincides with the rotation axis of the fixed roller.

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