Assembling device for interference sleeving pressing piece

Abstract

The assembling device comprises an interference sleeve piece to be assembled and an inner core rod, the interference sleeve piece is provided with a sleeve opening in the axis direction, and after the interference sleeve piece and the inner core rod are assembled, one section of the inner core rod is in interference sleeve connection with the sleeve opening in the axis direction; the assembling device comprises a suite clamp, a lifting platform, a downward pressing rod and a downward pressing driving device. The interference suite is fixedly mounted on the suite clamp in a vertical posture, and a sleeve opening faces upwards; the lower pressing rod is arranged above the external member clamp, in the working state, the lower end of the lower pressing rod abuts against the upper end of the inner core rod, and the lower end of the inner core rod is aligned with a sleeve opening in the interference external member; and the problem that after leaving a factory, the interference kit is very easy to crack and damage under the conditions of impact, temperature change and the like in the later use process can be avoided.

Description

Technical Field

[0001] The invention belongs to the field of interference set assembly. Background Art

[0002] In order to enhance the strength of the long plastic parts, a metal inner core rod can be inserted into the plastic set in the form of interference fit, such as Figure 1 As shown, a high-strength structure is formed. This structure of a metal inner core rod in a plastic set is widely used in fitness equipment and other fields;

[0003] In the existing assembly process of the interference sleeve 17 and the inner core rod 19, an impact device is generally used to impact the inner core rod 19 along the axial direction, so that the inner core rod 19 is inserted into the sleeve 18 of the interference sleeve 17 under the action of axial impact. This process is characterized by high efficiency and speed.

[0004] However, in practice, due to defects in the mold process of the interference fit kit 17, there are a small number of interference fit kits 17 whose sleeve openings 18 are narrow as a whole or in part. If the inner core rod 19 is forcibly inserted into the too narrow sleeve opening 18 of the interference fit kit 17, the inner core rod 19 will form an excessively large expansion force on the inner wall of the interference fit kit 17 after being inserted into the too narrow sleeve opening 18. Since the interference fit kit 17 itself is a plastic part, expansion cracks may not occur immediately. However, after this interference fit kit 17 leaves the factory, it is very easy to crack and damage under conditions such as impact and temperature changes during later use, which in turn affects the after-sales and reputation of the product. Summary of the invention

[0005] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides an assembly device for an interference fit sleeve compression piece to avoid the problem of cracking and damage of the interference fit sleeve piece during subsequent use after leaving the factory due to impact and temperature changes.

[0006] Technical solution: To achieve the above-mentioned purpose, an assembly device for an interference fit compression piece of the present invention comprises an interference fit sleeve and an inner core rod to be assembled, the interference fit sleeve is provided with a sleeve opening along the axial direction, after the interference fit sleeve and the inner core rod are assembled, a section of the inner core rod is interference fit in the sleeve opening along the axial direction.

[0007] The assembly device includes a kit fixture, a lifting platform, a pressing rod and a pressing driving device; the interference kit is fixedly installed on the kit fixture in a vertical posture, with the sleeve opening facing upward;

[0008] The lower pressure rod is above the set fixture. In the working state, the lower end of the lower pressure rod presses the upper end of the inner core rod, and the lower end of the inner core rod is aligned with the sleeve opening on the interference set;

[0009] The pressing rod is synchronized with the lifting platform; the pressing driving device drives the lifting platform.

[0010] Furthermore, it comprises a fixed bracket, a vertical wall is fixedly arranged on one side of the fixed bracket, and the downward pressing driving device is installed on the upper part of the vertical wall.

[0011] Furthermore, the downward pressing driving device includes a hinge seat fixed to one side of the upper end of the vertical wall, a lifting rod guide sleeve, a lifting rod, a connecting rod, a rocker arm, a driving arm and a handle.

[0012] Furthermore, the lifting rod guide sleeve is fixed at the lower end of the articulated seat, the lifting rod moves through the vertical guide channel on the lifting rod guide sleeve, the lower end of the lifting rod is fixedly connected to the lifting platform, the upper end of the lifting rod is hingedly connected to one end of the connecting rod through an a hinge, one end of the rocker arm is cross-connected to the articulated seat through a second hinge, and the other end of the connecting rod is hinged to the other end of the rocker arm through a c hinge; one end of the driving arm is fixedly connected to one end of the rocker arm close to the c hinge, and the other end of the driving arm is fixedly connected to the handle.

[0013] Furthermore, the upper end of the lower pressure rod is fixedly connected to the lifting platform.

[0014] Furthermore, a linear bearing guide is fixedly provided at one end of the lifting platform away from the vertical wall, and the lower pressure rod passes vertically coaxially and guides the matching linear bearing guide; the lower pressure rod moves up and down under the guidance of the linear bearing guide.

[0015] Furthermore, the surface of the vertical wall close to the lifting platform is the friction surface a, a vertical seat is fixedly installed in the middle of the lower side of the lifting platform, a semicircular eccentric self-locking wheel is arranged on the side of the vertical seat away from the lower pressure rod, and a horizontal roller bracket is fixedly arranged on the side of the middle part of the vertical seat close to the semicircular eccentric self-locking wheel;

[0016] The outer peripheral surface of the semicircular eccentric self-locking wheel is a closed loop outer peripheral surface formed by connecting the arc surface a and the vertical surface b end to end; the arc surface a and the vertical surface b face the vertical wall and the vertical seat side respectively; in the initial state, there is a gap between the arc surface a and the friction surface a;

[0017] The bearing hole at the eccentric position of the semicircular eccentric self-locking wheel rotates with the roller bracket through a sliding bearing. The axis of the bearing hole at the eccentric position of the semicircular eccentric self-locking wheel is assumed to be the first axis a, and the axis of the arc surface a is assumed to be the second axis b; the first axis a and the second axis b are on the same horizontal line, and the first axis a is closer to the friction surface a than the second axis b; when the semicircular eccentric self-locking wheel rotates clockwise around the first axis a, the gap gradually narrows, and the arc surface a is pressed tangent to the friction surface a.

[0018] Furthermore, a pair of transverse guide holes are provided in the lower section of the vertical seat, a pair of transverse guide rods are movably passed through the pair of transverse guide holes, one end of the pair of transverse guide rods close to the semicircular eccentric self-locking wheel is jointly fixedly connected to the push block, and one end of the pair of transverse guide rods away from the semicircular eccentric self-locking wheel is jointly fixedly connected to the roller support, and a pressure control roller is rotatably installed on the roller support through a bearing; an arc-shaped pressure control bayonet is provided on the side of the lower pressure rod close to the pressure control roller, the inner contour of the arc-shaped pressure control bayonet is adapted to the outer contour of the pressure control roller, and the pressure control roller is rolled and clamped in the arc-shaped pressure control bayonet, and the outer contour of the pressure control roller is closely attached to the inner contour of the arc-shaped pressure control bayonet. The upper end of the vertical seat is fixed with a thrust spring seat on one side close to the semicircular eccentric self-locking wheel, and the thrust spring seat is coaxially connected with a thrust spring on one side close to the semicircular eccentric self-locking wheel. The other end of the thrust spring is fixedly connected to the upper end of the vertical surface b and applies a thrust, which makes the semicircular eccentric self-locking wheel tend to rotate counterclockwise around the first axis a; the lower end of the vertical surface b is limited by the top pressure contact push block; under the thrust of the thrust spring and the force transmission of the semicircular eccentric self-locking wheel, the push block, the transverse guide rod and the roller support, the outer contour of the pressure control roller is tightly pressed and fitted with the inner contour of the arc-shaped pressure control bayonet, so as to realize the positioning of the lower pressure rod and make the lower pressure rod rise and fall synchronously with the lifting platform.

[0019] Beneficial effect: The present invention realizes the downward force control of the downward pressure rod without using any electrical components and sensors, avoids forcibly inserting the inner core rod downward into the overly narrow sleeve opening of the interference set with interference fit, which will later expand and damage the interference set, and avoids the problem that the interference set is very likely to crack and be damaged during later use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a disassembly diagram of the interference kit and the inner core rod;

[0021] Figure 2 is an overall diagram of the first embodiment;

[0022] Figure 3 is an overall diagram of the second embodiment;

[0023] Figure 4 for Figure 3 An enlarged schematic diagram of the area marked 23 in FIG. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] As attached Figures 1 to 4 An assembly device for an interference sleeve pressure piece is shown, such as Figure 1 It comprises an interference sleeve 17 and an inner core rod 19 to be assembled. The interference sleeve 17 is provided with a sleeve opening 18 along the axial direction. After the interference sleeve 17 and the inner core rod 19 are assembled, a section of the inner core rod 19 is interference sleeved in the sleeve opening 18 along the axial direction.

[0026] like Figure 2 The assembly device includes a kit fixture 22, a lifting platform 14, a pressing rod 13 and a pressing drive device 41; the interference kit 17 is fixedly installed on the kit fixture 22 in a vertical posture, and the sleeve 18 faces upward; the pressing rod 13 is above the kit fixture 22, and in the working state, the lower end of the pressing rod 13 presses the upper end of the inner core rod 19, and the lower end of the inner core rod 19 is aligned with the sleeve 18 on the interference kit 17; the pressing rod 13 is synchronized with the lifting platform 14; the pressing drive device 41 drives the lifting platform 14.

[0027] It also includes a base 21 and a fixed bracket 20 , the kit clamp 22 is installed on the base 21 , a vertical wall 3 is fixedly provided on one side of the fixed bracket 20 , and a downward pressing drive device 41 is installed on the upper part of the vertical wall 3 .

[0028] like Figure 2 The downward pressing driving device 41 includes a hinge seat 30 fixed to one side of the upper end of the vertical wall 3, a lifting rod guide sleeve 32, a lifting rod 15, a connecting rod 26, a rocker arm 28, a driving arm 27 and a handle 24;

[0029] The lifting rod guide sleeve 32 is fixed to the lower end of the articulated seat 30, and the lifting rod 15 moves through the vertical guide channel 43 on the lifting rod guide sleeve 32. The lower end of the lifting rod 15 is fixedly connected to the lifting platform 14, and the upper end of the lifting rod 15 is hingedly connected to one end of the connecting rod 26 through the a hinge 25. One end of the rocker arm 28 is connected to the articulated seat 30 through the second hinge 29, and the other end of the connecting rod 26 is hinged to the other end of the rocker arm 28 through the c hinge 31; one end of the driving arm 27 is fixedly connected to one end of the rocker arm 28 close to the c hinge 31, and the other end of the driving arm 27 is fixedly connected to the handle 24; the downward driving device 41 constitutes a labor-saving structure, and the lifting platform 14 can be lifted up and down by manually pulling the handle 24.

[0030] Based on the above structure, this solution provides the following two embodiments:

[0031] First embodiment:

[0032] like Figure 2 As shown, the upper end of the push rod 13 is fixedly connected to the lifting platform 14. In the case of this embodiment, although the resistance of the push rod 13 can be known through the force feedback of the staff, the downward pressure applied by the push rod 13 cannot be fully controlled because each person's perception of the force is different.

[0033] Second embodiment:

[0034] like Figure 3 and 4As shown, a linear bearing guide 12 is fixedly provided at one end of the lifting platform 14 away from the vertical wall 3, and a lower pressure rod 13 passes through and guides the matching linear bearing guide 12 coaxially vertically; the lower pressure rod 13 moves up and down under the guidance of the linear bearing guide 12; the surface of the vertical wall 3 close to the lifting platform 14 is a friction surface 3a, and a vertical seat 8 is fixedly installed in the middle of the lower side of the lifting platform 14, and a semicircular eccentric self-locking wheel 1 is provided on the side of the vertical seat 8 away from the lower pressure rod 13, and a horizontal roller bracket 6 is fixedly provided on the side of the middle of the vertical seat 8 close to the semicircular eccentric self-locking wheel 1; the outer peripheral surface of the semicircular eccentric self-locking wheel 1 is a closed-loop outer peripheral surface formed by connecting the arc surface 1a and the vertical surface 1b end to end; the arc surface 1a and the vertical surface 1b face the vertical wall 3 and the vertical seat 8 side respectively; in the initial state, there is a gap 91 between the arc surface 1a and the friction surface 3a; the bearing hole 80 at the eccentric position of the semicircular eccentric self-locking wheel 1 rotates with the roller bracket 6 through the sliding bearing 4, and the axis of the bearing hole 80 at the eccentric position of the semicircular eccentric self-locking wheel 1 is set as the first axis 2a, and the axis of the arc surface 1a is set as the second axis 2b; the first axis 2a and the second axis 2b are on the same horizontal line, and the first axis 2a is closer to the friction surface 3a than the second axis 2b; when the semicircular eccentric self-locking wheel 1 rotates clockwise around the first axis 2a, the gap 91 gradually narrows, and the friction surface 3a is pressed tangentially to the arc surface 1a;

[0035] The lower section of the vertical seat 8 is provided with a pair of transverse guide holes 72 which are transversely penetrated, and a pair of transverse guide rods 7 are transversely movable through the pair of transverse guide holes 72, and one end of the pair of transverse guide rods 7 close to the semicircular eccentric self-locking wheel 1 is fixedly connected to the push block 5, and one end of the pair of transverse guide rods 7 away from the semicircular eccentric self-locking wheel 1 is fixedly connected to the roller support 100, and a pressure control roller 10 is rotatably installed on the roller support 100 through a bearing; a circular arc-shaped pressure control bayonet 9 is provided on the side of the lower pressure rod 13 close to the pressure control roller 10, and the inner contour of the circular arc-shaped pressure control bayonet 9 is adapted to the outer contour of the pressure control roller 10, and the pressure control roller 10 is rolled and clamped in the circular arc-shaped pressure control bayonet 9, and the outer contour of the pressure control roller 10 is in line with the inner contour of the circular arc-shaped pressure control bayonet 9; the vertical seat 8 is provided with a pair of transverse guide holes 72 which are transversely penetrated, and the pair of transverse guide rods 7 are fixedly connected to the push block 5 at one end of the pair of transverse guide rods 7 close to the semicircular eccentric self-locking wheel 1 A thrust spring seat 11 is fixed to one side of the upper end of the seat 8 close to the semicircular eccentric self-locking wheel 1, and a thrust spring 16 is coaxially connected to one side of the thrust spring seat 11 close to the semicircular eccentric self-locking wheel 1. The other end of the thrust spring 16 is fixedly connected to the upper end of the vertical surface 1b and applies a thrust, which makes the semicircular eccentric self-locking wheel 1 tend to rotate counterclockwise around the first axis 2a; the lower end of the vertical surface 1b is limited and pressed into contact with the push block 5; under the thrust of the thrust spring 16 and the force transmission of the semicircular eccentric self-locking wheel 1, the push block 5, the transverse guide rod 7 and the roller support 100, the outer contour of the pressure control roller 10 is tightly pressed and fitted with the inner contour of the arc-shaped pressure control bayonet 9, so as to realize the positioning of the lower pressure rod 13 and make the lower pressure rod 13 rise and fall synchronously with the lifting platform 14.

[0036] Working principle of the second embodiment: Step 1, the interference sleeve 17 is fixedly mounted on the sleeve fixture 22 in a vertical posture, with the sleeve opening 18 facing upward; then the vertical inner core rod 19 is held, and the lower end of the inner core rod 19 is aligned with the sleeve opening 18 on the interference sleeve 17;

[0037] Step 2, set a critical pressure value F, pull the handle 24 by hand, and drive the lifting platform 14 to descend under the transmission of the labor-saving transmission structure of the downward pressure driving device 41, so that the downward pressure rod 13 follows the lifting platform 14 to descend synchronously; then the downward pressure rod 13 follows the lifting platform 14 to descend to the lower end to press the inner core rod 19, and the inner core rod 19 is inserted into the sleeve 18 of the interference set 17 with downward interference fit under the downward pressure of the downward pressure rod 13, until a section of the inner core rod 19 is interference-fitted in the sleeve 18 along the axial direction, and the interference fit set assembly is completed;

[0038] During the process of inserting the inner core rod 19 into the sleeve 18 of the interference set 17 with downward interference fit in the above step 2, if the downward thrust of the inner core rod 19 by the lower pressure rod 13 does not exceed the critical pressure value F, the lateral component force exerted by the inner wall surface of the arc-shaped pressure control bayonet 9 on the pressure control roller 10 is insufficient to overcome the thrust of the thrust spring 16, so that the outer contour of the pressure control roller 10 and the inner contour of the arc-shaped pressure control bayonet 9 are always in a state of close pressing and fitting, so that during the step 2, the lower pressure rod 13 and the lifting platform 14 are always synchronized, the semicircular eccentric self-locking wheel 1 does not rotate, there is a gap 91 between the arc surface 1a and the friction surface 3a, and the friction surface 3a does not form a resistance to the descent of the lifting platform 14;

[0039] In the above process, if the downward thrust of the pressing rod 13 on the inner core rod 19 exceeds the critical pressure value F, it means that the sleeve 18 is overall or partially narrow, resulting in excessive downward resistance. It is necessary to trim the sleeve 18 before pressing down and then insert it. If the inner core rod 19 is forced to be inserted downward into the too narrow sleeve 18 of the interference sleeve 17 with an interference fit, the inner core rod 19 will expand and damage the interference sleeve 17 after being inserted into the too narrow sleeve 18, making the interference sleeve 17 very likely to crack and be damaged during later use.

[0040] In the process of inserting the inner core rod 19 into the sleeve 18 of the interference fit set 17 in the above step 2, if the downward thrust of the pressing rod 13 on the inner core rod 19 exceeds the critical pressure value F, the lateral force applied by the inner wall of the arc-shaped pressure control bayonet 9 to the pressure control roller 10 is just enough to overcome the thrust of the thrust spring 16, so that the pressure control roller 10 will roll out of the arc-shaped pressure control bayonet 9 (it will not roll out completely), and the pressure control roller 10 will roll out of the arc-shaped pressure control bayonet 9. At the initial stage of the inner rolling-out action, the pressure roller 10 is laterally offset under the guidance of the transverse guide hole 72, and then the push block 5 pushes the lower end of the vertical surface 1b laterally under the linkage of the transverse guide rod 7, so that the semicircular eccentric self-locking wheel 1 rotates clockwise around the first axis 2a, so that the gap 91 is gradually narrowed until the arc surface 1a of the semicircular eccentric self-locking wheel 1 rolls tangent to the friction surface 3a; at the same time, the lifting platform 14 continues to descend under the drive of the downward pressure driving device 41, so that the roller The bracket 6 drives the semicircular eccentric self-locking wheel 1 to descend. Since the arc surface 1a of the semicircular eccentric self-locking wheel 1 has been rolling tangent to the friction surface 3a, the descending movement of the semicircular eccentric self-locking wheel 1 will drive itself to further rotate clockwise around the first axis 2a under the drive of the rolling friction force. Since the first axis 2a is closer to the friction surface 3a than the second axis 2b, during the further clockwise rotation of the semicircular eccentric self-locking wheel 1 around the first axis 2a, the contact position of the friction surface 3a and the arc surface 1a will have motion interference, so that the interaction pressure between the friction surface 3a and the arc surface 1a will increase instantly with the descent of the lifting platform 14, thereby instantly increasing the friction force between the friction surface 3a and the arc surface 1a, thereby preventing the lifting platform 14 and the down-pressing rod 13 from further descending under the drive of the down-pressing driving device 41, and preventing the inner core rod 19 from being inserted into the too narrow sleeve 18 and damaging the interference fit kit 17; at this time, the too narrow sleeve 18 needs to be trimmed and reassembled.

[0041] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An assembly device for an interference sleeve compression piece, comprising an interference sleeve (17) and an inner core rod (19) to be assembled, the interference sleeve (17) being provided with a sleeve opening (18) along the axial direction, and after the interference sleeve (17) and the inner core rod (19) are assembled, a section of the inner core rod (19) is interference sleeved in the sleeve opening (18) along the axial direction; Features: The assembly device comprises a set clamp (22), a lifting platform (14), a pressing rod (13) and a pressing driving device (41); the interference set (17) is fixedly mounted on the set clamp (22) in a vertical posture, with the sleeve opening (18) facing upwards; The lower pressing rod (13) is located above the sleeve clamp (22). In the working state, the lower end of the lower pressing rod (13) presses the upper end of the inner core rod (19), and the lower end of the inner core rod (19) is aligned with the sleeve opening (18) on the interference sleeve (17); The pressing rod (13) is synchronized with the lifting platform (14); the pressing drive device (41) drives and connects the lifting platform (14).

2. The assembly device of the interference sleeve pressure piece according to claim 1, characterized in that: It comprises a fixed bracket (20), a vertical wall (3) is fixedly arranged on one side of the fixed bracket (20), and the downward pressing driving device (41) is installed on the upper part of the vertical wall (3).

3. The assembly device of the interference sleeve pressure piece according to claim 2, characterized in that: The downward pressing driving device (41) comprises a hinge seat (30) fixed to one side of the upper end of the vertical wall (3), a lifting rod guide sleeve (32), a lifting rod (15), a connecting rod (26), a rocker arm (28), a driving arm (27) and a handle (24).

4. The assembly device of the interference sleeve pressure piece according to claim 3, characterized in that: The lifting rod guide sleeve (32) is fixed to the lower end of the articulated seat (30); the lifting rod (15) moves through the vertical guide channel (43) on the lifting rod guide sleeve (32); the lower end of the lifting rod (15) is fixedly connected to the lifting platform (14); the upper end of the lifting rod (15) is hingedly connected to one end of the connecting rod (26) through an a hinge (25); one end of the rocker arm (28) is cross-connected to the articulated seat (30) through a second hinge (29); the other end of the connecting rod (26) is hingedly connected to the other end of the rocker arm (28) through a c hinge (31); one end of the driving arm (27) is fixedly connected to one end of the rocker arm (28) close to the c hinge (31); the other end of the driving arm (27) is fixedly connected to the handle (24).

5. The assembly device of the interference sleeve press piece according to claim 1, characterized in that: The upper end of the lower pressure rod (13) is fixedly connected to the lifting platform (14).

6. The assembly device of the interference sleeve press piece according to claim 1, characterized in that: A linear bearing guide (12) is fixedly provided at one end of the lifting platform (14) away from the vertical wall (3), and a lower pressure rod (13) passes through the linear bearing guide (12) coaxially and vertically and guides to cooperate with the linear bearing guide (12); the lower pressure rod (13) moves up and down under the guidance of the linear bearing guide (12).

7. The assembly device of the interference sleeve press piece according to claim 6, characterized in that: The surface of the vertical wall (3) close to the lifting platform (14) is a friction surface (3a); a vertical seat (8) is fixedly installed in the middle of the lower side of the lifting platform (14); a semicircular eccentric self-locking wheel (1) is arranged on the side of the vertical seat (8) away from the lower pressure rod (13); and a transverse roller bracket (6) is fixedly arranged on the side of the middle of the vertical seat (8) close to the semicircular eccentric self-locking wheel (1); The outer peripheral surface of the semicircular eccentric self-locking wheel (1) is a closed loop outer peripheral surface formed by connecting the arc surface (1a) and the vertical surface (1b) end to end; the arc surface (1a) and the vertical surface (1b) are respectively oriented toward the vertical wall (3) and the vertical seat (8); in the initial state, there is a gap (91) between the arc surface (1a) and the friction surface (3a); The bearing hole (80) at the eccentric position of the semicircular eccentric self-locking wheel (1) rotates with the roller bracket (6) through the sliding bearing (4), and the axis of the bearing hole (80) at the eccentric position of the semicircular eccentric self-locking wheel (1) is set as the first axis (2a), and the axis of the arc surface (1a) is set as the second axis (2b); the first axis (2a) and the second axis (2b) are on the same horizontal line, and the first axis (2a) is closer to the friction surface (3a) than the second axis (2b); when the semicircular eccentric self-locking wheel (1) rotates clockwise around the first axis (2a), the gap (91) gradually narrows, and the arc surface (1a) and the friction surface (3a) are tangentially pressed.

8. The assembly device of the interference sleeve pressure piece according to claim 7, characterized in that: The lower section of the vertical seat (8) is provided with a pair of transverse guide holes (72) that pass through the pair of transverse guide holes (72) in a transversely movable manner. The ends of the pair of transverse guide rods (7) close to the semicircular eccentric self-locking wheel (1) are fixedly connected to the push block (5) together, and the ends of the pair of transverse guide rods (7) away from the semicircular eccentric self-locking wheel (1) are fixedly connected to the roller support (100) together, and a pressure control roller (10) is rotatably mounted on the roller support (100) through a bearing; the lower pressure rod (13) is provided with an arc-shaped pressure control bayonet (9) on one side close to the pressure control roller (10), the inner contour of the arc-shaped pressure control bayonet (9) is adapted to the outer contour of the pressure control roller (10), and the pressure control roller (10) is rolled and clamped in the arc-shaped pressure control bayonet (9), and the outer contour of the pressure control roller (10) is fitted with the inner contour of the arc-shaped pressure control bayonet (9). A thrust spring seat (11) is fixed to the upper end of the vertical seat (8) on one side close to the semicircular eccentric self-locking wheel (1); a thrust spring (16) is coaxially connected to the thrust spring seat (11) on one side close to the semicircular eccentric self-locking wheel (1); the other end of the thrust spring (16) is fixedly connected to the upper end of the vertical surface (1b) and applies a thrust force, which makes the semicircular eccentric self-locking wheel (1) tend to rotate counterclockwise around the first axis (2a); The lower end of the vertical surface (1b) is limited in position and pressed against the push block (5); under the thrust of the thrust spring (16) and the force transmission of the semicircular eccentric self-locking wheel (1), the push block (5), the transverse guide rod (7) and the roller support (100), the outer contour of the pressure control roller (10) and the inner contour of the arc-shaped pressure control bayonet (9) are tightly pressed and fitted, thereby achieving the positioning of the lower pressure rod (13) and making the lower pressure rod (13) and the lifting platform (14) rise and fall synchronously.

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