Rotary folding board device for gauze folding
By designing a rotary folding plate device for folding gauze, and utilizing a combination of a support plate, a folding plate main shaft, and a rotating arm, automated folding of gauze is achieved, solving the problems of complex structure and high maintenance costs of existing equipment, and improving production efficiency and product quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XINGTU INTELLIGENT EQUIPMENT (JIANGSU) CO LTD
- Filing Date
- 2025-09-02
- Publication Date
- 2026-07-07
AI Technical Summary
Existing gauze folding equipment has a complex structure and many parts, resulting in high assembly and maintenance costs and a tendency to malfunction, which affects production efficiency and product quality.
A rotary folding plate device for folding gauze was designed, including a support plate, a folding plate main shaft, a rotating arm, and a toothed belt. The rotating arm and folding plate are driven by an external motor to realize the automated folding of gauze, reducing the number of parts and realizing the compression folding of gauze by reverse rotation.
It simplifies the equipment structure, reduces assembly and maintenance costs, improves production efficiency and folding quality, achieves automated production, and reduces labor costs.
Smart Images
Figure CN224467198U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a rotary folding plate device for folding gauze, belonging to the field of gauze folding device design technology. Background Technology
[0002] In the field of medical supplies manufacturing, gauze is a common medical dressing. Currently, the production of medical gauze sheets can be carried out by manual cutting and folding or by using automatic gauze folding machines. With the rise in labor costs and the difficulty in recruiting workers, various companies hope to improve production efficiency and reduce production costs by investing in machines. At the same time, they hope to solve the problem of labor shortage and the problem of uneven folds that are easy to occur by manual folding.
[0003] Currently, some gauze folding machines on the market fold gauze on conveyor lines. However, these machines still have some shortcomings in the folding process. The main issues are the complex structure and numerous parts of their core folding components, leading to high assembly and maintenance costs. Furthermore, they are prone to malfunctions after prolonged operation, affecting production schedules. Therefore, developing a rotary folding plate device for gauze folding machines that is simple in structure, stable in operation, provides good folding results, and enables automated production is of significant practical importance for improving gauze production efficiency, reducing production costs, and enhancing product quality. Utility Model Content
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a rotating folding plate device for folding gauze.
[0005] To achieve the above-mentioned utility model objectives, the technical solution adopted by this utility model is as follows: A rotating folding plate device for folding gauze, characterized in that: it includes a support plate, a folding plate main shaft, and a rotating arm; the support plate has a rotating hole, a fixed gear is fixed on the front side of the support plate, the fixed gear has a fixed gear through hole, and a bearing is fixed on the back side of the support plate; the folding plate main shaft passes through the fixed gear through hole, the rotating hole, and the bearing in sequence and is fixed to the inner ring of the bearing, and the front end of the folding plate main shaft extends out of the fixed gear through hole, and the rear end extends out of the bearing; the front end of the folding plate main shaft is fixedly connected to the rotating arm, and the rear end serves as the power transmission end connected to an external motor drive, and the rotating arm rotates with the rotation of the folding plate main shaft;
[0006] The rotating arm has a shaft seat and a bearing seat on each of its two sides facing the support plate. A tensioning shaft is rotatably connected to the shaft seat, and a tensioning gear is installed on the tensioning shaft. A folding insert shaft through hole is opened on the side of the rotating arm where the bearing seat is installed. A folding insert shaft bearing is installed in the folding insert shaft through hole and is installed on the bearing seat and fixed to the bearing seat. A folding insert shaft is also provided, which passes through and is fixed to the inner ring of the folding insert shaft bearing. The front end and rear end of the folding insert shaft extend out of the folding insert shaft bearing. The rear end of the folding insert shaft faces the support plate, and a driven gear is fixedly installed at the rear end of the folding insert shaft. A folding insert is installed at the front end of the folding insert shaft, and the folding insert is arranged along the length direction of the front end of the folding insert shaft.
[0007] The tensioning gear, the fixed gear, and the driven gear are all wrapped with toothed belts.
[0008] When in use, an external motor drives the folding plate spindle to rotate, and the rotation of the folding plate spindle causes the rotating arm, which is fixed to the folding plate spindle, to rotate.
[0009] Since the fixed gear is fixed to the support plate, it remains in a fixed state when the rotating arm rotates. Thus, the rotation of the rotating arm transmits power to the driven gear through the toothed belt, causing the driven gear to rotate in the opposite direction to the rotating arm, which in turn causes the folding insert to rotate in the opposite direction to the rotating arm.
[0010] When the rotating arm rotates to the point where the end with the folding insert faces the gauze to be folded, the folding insert and the rotating arm rotate in opposite directions to contact the gauze to be folded and squeeze the gauze to achieve folding; after folding, the rotating arm continues to rotate and the folding insert leaves the gauze until the rotating arm and the folding insert continue to rotate in opposite directions to squeeze and fold the next piece of gauze to be folded.
[0011] The fixed gear perforation and the inner ring of the bearing are both concentric with the rotating hole on the support plate.
[0012] The folding insert shaft is provided with a mounting groove, which is arranged along the length of the front end of the folding insert shaft. The folding insert is fixed to the mounting groove by bolts.
[0013] The mounting groove is provided with several threaded holes, and the folding insert plate is provided with several elliptical through holes corresponding to the threaded holes. The screws of several bolts are screwed into the corresponding elliptical through holes on the folding insert plate and the threaded holes on the mounting groove in sequence, and the folding insert plate is clamped and fixed on the folding insert plate shaft by the bolt nuts. Loosen the bolts, and the folding insert plate can move to a position in the mounting groove through the elliptical through holes. After moving to a suitable position, tighten the bolts, and clamp the folding insert plate and the folding insert plate shaft by the bolt nuts, so that the folding insert plate is fixed to the front end of the folding insert plate shaft.
[0014] The rotating arm is provided with at least two moving slots that pass through both sides of the rotating arm, and also with an adjusting slider. The adjusting slider is provided with moving posts equal in number to the moving slots. Each moving post passes through the corresponding moving slot and is fixed to the shaft seat.
[0015] The rotating arm is fixed with an adjusting block, which has a threaded through hole. It also has a threaded rod that is screwed onto and passes through the threaded through hole on the adjusting block. By rotating the threaded rod, the adjusting slider is pushed, causing the adjusting slider to move along the moving groove. When the position of the adjusting slider is adjusted, the belt has a pull-back force, which also causes the adjusting slider to move, thereby achieving the tensioning of the belt by the tensioning gear.
[0016] The end of the rotating threaded rod facing the adjusting slider is provided with a push seat for conveniently pushing the adjusting slider, and the outer diameter of the push seat is larger than the outer diameter of the rotating threaded rod.
[0017] A support plate bearing seat is fixed to the back of the support plate, and the bearing is fixedly installed on the support plate bearing seat.
[0018] The rotating arm has a through hole in the middle. The front end of the folding plate main shaft passes through the through hole and is fixed with a rotating arm fixing ring. One side of the rotating arm fixing ring has a slit. Both the upper and lower parts of the rotating arm fixing ring have threaded through holes. Fastening bolts are also provided. After the rotating arm fixing ring is fitted onto the folding plate main shaft, the fastening bolts are screwed into the threaded through holes on the upper and lower parts of the slit in sequence, so that the rotating arm fixing ring is clamped and fixed to the folding plate main shaft. The rotating arm fixing ring is then tightened and fixed to the rotating arm by at least two bolts, so that the folding plate main shaft and the rotating arm are fixedly connected.
[0019] This utility model has a reasonable and simple structure and is easy to use. Structurally, it includes a support plate, a folding plate main shaft, a rotating arm, and a toothed belt. The support plate has a rotating hole, a fixed gear is fixed on the front, and a bearing is fixed on the back. The folding plate main shaft passes sequentially through the fixed gear hole, the rotating hole, and the bearing, and is fixed to the inner ring of the bearing. The front end extends out of the fixed gear hole, and the rear end extends out of the bearing. The front end is fixedly connected to the rotating arm, and the rear end serves as the power transmission end. The rotating arm has a shaft seat and a bearing seat on each side facing the support plate. A tensioning shaft is rotatably connected to the shaft seat, and a tensioning gear is installed on the tensioning shaft. A folding plate shaft bearing is installed on the bearing seat, and the folding plate shaft passes through and is fixed to the inner ring of the bearing. A folding plate is installed at the front end of the folding plate shaft, and a driven gear is fixedly installed at the rear end. The toothed belt is wound around the tensioning gear, the fixed gear, and the driven gear.
[0020] In use, an external motor drives the folding plate's main shaft to rotate, which in turn rotates the rotating arm. A fixed gear is mounted on a support plate. As the rotating arm rotates, power is transmitted to the driven gear via a toothed belt, causing the driven gear to rotate in the opposite direction to the rotating arm, which in turn drives the folding insert to rotate in the opposite direction to the rotating arm. When the rotating arm rotates to the point where the folding insert faces the gauze to be folded, the folding insert rotates in the opposite direction to the rotating arm and comes into contact with the gauze, compressing it to achieve folding. After folding, the rotating arm continues to rotate, the folding insert leaves the gauze, and the process continues to fold the next piece of gauze.
[0021] Preferably, in this invention, the fixed gear through hole, the bearing inner ring, and the rotating hole on the support plate are concentric.
[0022] In this invention, a mounting groove is provided on the folding insert shaft. The folding insert is fixed to the mounting groove by bolts, and the nuts of the bolts clamp the folding insert and the folding insert shaft. The mounting groove has threaded holes, and the folding insert has corresponding elliptical through holes. Bolts pass through the through holes and threaded holes to fix the folding insert. Loosening the bolts can adjust the position of the folding insert.
[0023] In this invention, the rotating arm is provided with at least two movable slots and an adjusting slider. A movable column on the adjusting slider passes through the movable slot and is fixed to the shaft seat. An adjusting block is fixed to the rotating arm, and the adjusting block has a threaded through hole. A threaded rod is screwed into the threaded through hole on the adjusting block. By rotating the threaded rod, the adjusting slider is pushed, causing the adjusting slider to move along the movable slot. When the position of the adjusting slider is adjusted, the belt has a pull-back force, which also causes the adjusting slider to move, thereby achieving the tensioning of the belt by the tensioning gear.
[0024] In practical use, the support plate can be installed and fixed on the support frame and other components as needed. This invention reduces the number of parts, lowering assembly and maintenance costs. The reverse rotation of the rotating arm and folding insert achieves the compression and folding of the gauze, improving folding quality. In use, it can be connected to an external motor drive for automated folding, increasing production efficiency, reducing labor costs, and possessing significant market application and promotion value. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the structure of this utility model;
[0026] Figure 2 This is a schematic diagram of the structure of this utility model from another angle;
[0027] Figure 3 This is a schematic diagram of the structure after removing the bearing housing in this utility model;
[0028] Figure 4 This is a structural schematic diagram of the present invention from the rear view.
[0029] In the diagram: 1. Support plate, 2. Folding plate main shaft, 3. Rotating arm, 4. Fixed gear, 5. Fixed gear through hole, 6. Bearing, 7. Shaft seat, 8. Bearing seat, 9. Tensioning shaft, 10. Tensioning gear, 11. Folding insert plate shaft bearing, 12. Folding insert plate shaft, 13. Driven gear, 14. Folding insert plate, 15. Belt, 16. Mounting groove, 17. Bolt, 18. Elliptical through hole, 19. Adjusting slider, 20. Moving column, 21. Adjusting block, 22. Threaded through hole, 23. Threaded rod, 24. Moving groove, 25. Rotating arm fixing ring, 26. Fastening bolt, 27. Push seat, 28. Support plate bearing seat. Detailed Implementation
[0030] The present invention will be further described below with reference to the accompanying drawings and descriptions.
[0031] A rotating folding plate device for folding gauze includes a support plate 1, a folding plate main shaft 2, and a rotating arm 3. A rotating hole is opened on the support plate 1, a fixed gear 4 is fixed on the front side of the support plate 1, and a fixed gear through hole 5 is provided on the fixed gear 4. A bearing 6 is fixed on the back side of the support plate 1. The folding plate main shaft 2 passes through the fixed gear through hole 5, the rotating hole, and the bearing 6 in sequence and is fixed to the inner ring of the bearing 6. The front end of the folding plate main shaft 2 extends out of the fixed gear through hole 5, and the rear end extends out of the bearing 6. The front end of the folding plate main shaft 2 is fixedly connected to the rotating arm 3, and the rear end serves as the power transmission end connected to an external motor drive. The rotating arm 3 rotates as the folding plate main shaft 2 rotates.
[0032] A shaft seat 7 and a bearing seat 8 are respectively provided on both sides of the rotating arm 3 facing the support plate 1. A tensioning shaft 9 is rotatably connected to the shaft seat 7, and a tensioning gear 10 is installed on the tensioning shaft 9. A folding insert shaft through hole is opened on one side of the rotating arm 3 where the bearing seat 8 is installed. A folding insert shaft bearing 11 is installed in the folding insert shaft through hole and is installed on the bearing seat 8 and fixed to the bearing seat 8. A folding insert shaft 12 is also provided. The folding insert shaft 12 passes through and is fixed to the inner ring of the folding insert shaft bearing 11, and the front end and rear end of the folding insert shaft 12 extend out of the folding insert shaft bearing 11 respectively. The rear end of the folding insert shaft 12 faces the support plate 1, and a driven gear 13 is fixedly installed at the rear end of the folding insert shaft 12. A folding insert 14 is installed at the front end of the folding insert shaft 12 and is arranged along the length direction of the front end of the folding insert shaft 12. A toothed belt 15 is wound around the tensioning gear 10, the fixed gear 4, and the driven gear 13.
[0033] In use, an external motor drives the folding plate main shaft 2 to rotate, and the rotation of the folding plate main shaft 2 drives the rotating arm 3, which is fixed to the folding plate main shaft 2, to rotate. Since the fixed gear 4 is fixed on the support plate 1, the fixed gear 4 remains fixed when the rotating arm 3 rotates. Thus, the rotation of the rotating arm 3 transmits power to the driven gear 13 through the toothed belt 15, causing the driven gear 13 to rotate in the opposite direction to the rotating arm 3, and then causing the folding insert 14 to rotate in the opposite direction to the rotating arm 3. When the rotating arm 3 rotates to the point where the end with the folding insert 14 is installed faces the gauze to be folded, the folding insert 14 and the rotating arm 3 rotate in opposite directions to contact the gauze to be folded and squeeze the gauze to be folded, thereby folding the gauze. After folding, the rotating arm 3 continues to rotate, and the folding insert 14 leaves the gauze, until the rotating arm 3 and the folding insert 14 continue to rotate in opposite directions to squeeze and fold the next piece of gauze to be folded.
[0034] Furthermore, the inner rings of the fixed gear through hole 5 and the bearing 6 are concentric with the rotating hole on the support plate 1.
[0035] A mounting groove 16 is provided on the folding insert shaft 12. The mounting groove 16 is arranged along the length direction of the front end of the folding insert shaft 12. The folding insert 14 is tightened and fixed to the mounting groove 16 by bolts 17.
[0036] Furthermore, several threaded holes are provided on the mounting groove 16, and several elliptical through holes 18 are provided on the folding insert plate 14 corresponding to the several threaded holes. The screws of several bolts 17 are screwed into the corresponding elliptical through holes 18 on the folding insert plate 14 and the threaded holes on the mounting groove 16 in sequence, and the folding insert plate 14 is clamped and fixed on the folding insert plate shaft 12 by the nuts of the bolts 17. Loosen the bolts 17, and the folding insert plate 14 can move to a position in the mounting groove 16 through the elliptical through holes 18. After moving to a suitable position, tighten the bolts 17, and clamp the folding insert plate 14 and the folding insert plate shaft 12 by the nuts of the bolts 17, so that the folding insert plate 14 is fixed to the front end of the folding insert plate shaft 12.
[0037] Furthermore, at least two moving slots 24 penetrating both sides of the rotating arm 3 are provided on the rotating arm 3, and an adjusting slider 19 is also provided. The adjusting slider 19 is provided with a number of moving columns 20 equal to the number of moving slots 24. Each moving column 20 passes through the corresponding moving slot 24 and is fixed to the bearing seat 7.
[0038] An adjusting block 21 is fixed on the rotating arm 3. The adjusting block 21 is provided with a threaded through hole 22. A threaded rod 23 is also provided. The threaded rod 23 is screwed into and passes through the threaded through hole 22 on the adjusting block 21. By rotating the threaded rod 23, the adjusting slider 19 is pushed, causing the adjusting slider 19 to move along the moving groove 24. When the position of the adjusting slider 19 is adjusted, the belt 15 has a pull-back force, which also causes the adjusting slider 19 to move, thereby achieving the tensioning of the belt 15 by the tensioning gear 10.
[0039] Furthermore, a pusher seat 27 is provided at the end of the rotating threaded rod facing the adjusting slider 19 to facilitate pushing the adjusting slider 19. The outer diameter of the pusher seat 27 is larger than the outer diameter of the rotating threaded rod.
[0040] Furthermore, a support plate bearing seat 28 is fixed on the back of the support plate 1, and the bearing 6 is fixedly installed on the support plate bearing seat 28.
[0041] To ensure a secure connection between the folding plate main shaft 2 and the rotating arm 3, the following method is employed: a rotating arm through hole is provided in the middle of the rotating arm 3, and a rotating arm fixing ring 25 is fixed after the front end of the folding plate main shaft 2 passes through the rotating arm through hole; a slit is left on one side of the rotating arm fixing ring 25, and threaded through holes are opened on both the upper and lower parts of the rotating arm fixing ring 25; fastening bolts 26 are also provided. After the rotating arm fixing ring 25 is fitted onto the folding plate main shaft 2, the fastening bolts 26 are screwed sequentially into the threaded through holes on the upper and lower parts of the slit, so that the rotating arm fixing ring 25 is clamped and fixed on the folding plate main shaft 2; the rotating arm fixing ring 25 is then tightened and fixed on the rotating arm 3 by at least two bolts.
[0042] The above description is merely a specific embodiment of this utility model and is not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A rotary folding plate device for folding gauze, characterized in that: The system includes a support plate (1), a folding plate main shaft (2), and a rotating arm (3). The support plate (1) has a rotating hole, and a fixed gear (4) is fixed on the front side of the support plate (1). The fixed gear (4) has a fixed gear through hole (5), and a bearing (6) is fixed on the back side of the support plate (1). The folding plate main shaft (2) passes through the fixed gear through hole (5), the rotating hole, and the bearing (6) in sequence and is fixed to the inner ring of the bearing (6). The front end of the folding plate main shaft (2) extends out of the fixed gear through hole (5), and the rear end extends out of the bearing (6). The front end of the folding plate main shaft (2) is fixedly connected to the rotating arm (3), and the rear end serves as the power transmission end connected to an external motor drive. The rotating arm (3) rotates with the rotation of the folding plate main shaft (2). The rotating arm (3) has a bearing seat (7) and a bearing seat (8) on its two sides facing the support plate (1). A tensioning shaft (9) is rotatably connected to the bearing seat (7), and a tensioning gear (10) is installed on the tensioning shaft (9). A folding insert shaft through hole is opened on one side of the rotating arm (3) where the bearing seat (8) is installed. A folding insert shaft bearing (11) is installed on the folding insert shaft through hole, and the folding insert shaft bearing (11) is installed on the bearing seat (8) and fixed to the bearing seat (8). The folding insert shaft (12) passes through and is fixed to the inner ring of the folding insert shaft bearing (11), and the front end and rear end of the folding insert shaft (12) extend out of the folding insert shaft bearing (11) respectively; the rear end of the folding insert shaft (12) faces the support plate (1), and a driven gear (13) is fixedly installed at the rear end of the folding insert shaft (12); a folding insert (14) is installed at the front end of the folding insert shaft (12), and the folding insert (14) is arranged along the length direction of the front end of the folding insert shaft (12); A toothed belt (15) is wound around the tension gear (10), the fixed gear (4), and the driven gear (13).
2. The rotary folding plate device for folding gauze according to claim 1, characterized in that: When in use, an external motor drives the folding plate main shaft (2) to rotate, and the rotation of the folding plate main shaft (2) drives the rotating arm (3) fixed to the folding plate main shaft (2) to rotate. Since the fixed gear (4) is fixed on the support plate (1), the fixed gear (4) is always in a fixed state when the rotating arm (3) rotates. Thus, the rotation of the rotating arm (3) transmits power to the driven gear (13) through the toothed belt (15), causing the driven gear (13) to rotate in the opposite direction to the rotating arm (3), and then causing the folding insert plate (14) to rotate in the opposite direction to the rotating arm (3). When the rotating arm (3) rotates to face the gauze to be folded at the end where the folding insert (14) is installed, the folding insert (14) and the rotating arm (3) rotate in opposite directions to contact the gauze to be folded and squeeze the gauze to be folded to achieve the folding of the gauze; after folding, the rotating arm (3) continues to rotate and the folding insert (14) leaves the gauze until the rotating arm (3) and the folding insert (14) continue to rotate in different directions to squeeze and fold the next gauze to be folded.
3. The rotary folding plate device for folding gauze according to claim 1, characterized in that: The inner rings of the fixed gear through hole (5) and the bearing (6) are concentric with the rotating hole on the support plate (1).
4. The rotary folding plate device for folding gauze according to claim 1, characterized in that: The folding insert shaft (12) is provided with an installation groove (16), which is arranged along the length direction of the front end of the folding insert shaft (12). The folding insert (14) is tightened and fixed on the installation groove (16) by bolts (17).
5. The rotary folding plate device for folding gauze according to claim 4, characterized in that: The mounting groove (16) is provided with several threaded holes, and the folding insert plate (14) is provided with several elliptical through holes (18) corresponding to the several threaded holes. The screws of several bolts (17) are screwed into the elliptical through holes (18) on the corresponding folding insert plate (14) and the threaded holes on the mounting groove (16) in sequence, and the folding insert plate (14) is clamped and fixed on the folding insert plate shaft (12) by the nuts of the bolts (17). The bolts (17) are loosened, and the folding insert plate (14) can move to the mounting groove (16) through the elliptical through holes (18). After moving to the appropriate position, the bolts (17) are tightened, and the folding insert plate (14) and the folding insert plate shaft (12) are clamped by the nuts of the bolts (17), so that the folding insert plate (14) is fixed to the front end of the folding insert plate shaft (12).
6. The rotary folding plate device for folding gauze according to claim 1, characterized in that: The rotating arm (3) is provided with at least two moving slots (24) that pass through both sides of the rotating arm (3), and is also provided with an adjusting slider (19). The adjusting slider (19) is provided with a number of moving columns (20) equal to the number of moving slots (24). Each moving column (20) passes through the corresponding moving slot (24) and is fixed to the bearing seat (7). The rotating arm (3) is fixed with an adjusting block (21), and the adjusting block (21) is provided with a threaded through hole (22); it is also provided with a threaded rod (23), which is screwed onto and passes through the threaded through hole (22) on the adjusting block (21). By rotating the threaded rod (23), the adjusting slider (19) is pushed, causing the adjusting slider (19) to move along the moving groove (24). When the position of the adjusting slider (19) is adjusted, the belt (15) has a pull-back force, which also causes the adjusting slider (19) to move, thereby realizing the tensioning of the belt (15) by the tensioning gear (10).
7. The rotary folding plate device for folding gauze according to claim 6, characterized in that: The threaded rod (23) has a push seat (27) at the end facing the adjusting slider (19) to facilitate pushing the adjusting slider (19). The outer diameter of the push seat (27) is larger than the outer diameter of the threaded rod (23).
8. The rotary folding plate device for folding gauze according to claim 1, characterized in that: The back of the support plate (1) is fixed with a support plate bearing seat (28), and the bearing (6) is fixedly installed on the support plate bearing seat (28).
9. The rotary folding plate device for folding gauze according to claim 1, characterized in that: The rotating arm (3) has a rotating arm through hole in the middle. The front end of the folding plate main shaft (2) passes through the rotating arm through hole and is fixed with a rotating arm fixing ring (25). One side of the rotating arm fixing ring (25) has a slit. The rotating arm fixing ring (25) above the slit and the rotating arm fixing ring (25) below the slit both have threaded through holes. Fastening bolts (26) are also provided. After the rotating arm fixing ring (25) is fitted onto the folding plate main shaft (2), the fastening bolts (26) are screwed into the threaded through holes above the slit and the threaded through holes below the slit in sequence, so that the rotating arm fixing ring (25) is clamped and fixed on the folding plate main shaft (2). The rotating arm fixing ring (25) is then tightened and fixed on the rotating arm (3) by at least 2 bolts, so that the folding plate main shaft (2) and the rotating arm (3) are fixedly connected.