Dual lift safety tongs

Abstract

The present application relates to a kind of double pulling safety tongs, and it is related to elevator component technical field, it includes tong body and the pair of clamping blocks being slidably arranged in tong body, the tong body is provided with tong mouth for guide rail to pass through, the clamping block can be against clamping guide rail, the tong body is provided with wedge block capable of being against clamping block, the clamping block is arranged between guide rail and wedge block, each described clamping block is provided with pulling rod connected with elevator speed limiter, the pulling rod is used to drive clamping block to move when elevator loses speed, the tong body is provided with reset component, and the reset component is used to drive clamping block to move reset.This application has the effect of reducing the probability of safety tongs misoperation, reduces safety risk.

Description

Technical Field

[0001] This invention relates to the field of elevator component technology, and in particular to a double-lifting safety clamp. Background Technology

[0002] The safety clamp is a safety protection device for elevators. Under the control of the speed governor, when the elevator speed exceeds the limit (or rated speed) set by the speed governor, or in the event of a breakage or slack in the suspension rope, the elevator safety clamp device will stop the car in an emergency and clamp it on the guide rail. It provides effective protection for the safe operation of the elevator and is generally installed on the car frame or counterweight frame.

[0003] A common safety clamp design consists of a clamp body structure fixed to the elevator car and slidably mounted on the elevator guide rail. A pair of clamping blocks are slidably mounted inside the clamp body, and wedge-shaped blocks within the clamp body abut against these blocks, causing the clamping blocks to slide at an angle. The safety clamp connects the clamping blocks to the elevator speed governor via a guide rod. The speed governor is connected to the guide rod via a steel cable. Under normal circumstances, the speed governor allows the steel cable to move with the elevator car and safety clamp. When the elevator stalls during ascent or descent, the speed governor activates to stop the steel cable and, through the guide rod, causes the clamping blocks inside the safety clamp to slide, clamping them against the guide rail. This results in the elevator car being stopped in an emergency and clamped onto the guide rail.

[0004] The most common guide rod is the lifting rod, and the most common safety gear uses a single lifting structure, that is, two sliders use the same lifting rod. The lower ends of the lifting rod are connected to the two sliders respectively. When the elevator car tilts severely due to severe uneven loading or other abnormal conditions, after one slider contacts the guide rail, because there is friction between the slider and the guide rail, the slider will drive the other slider to contact the guide rail through the lifting rod. When both sliders are in contact with the guide rail, it will cause the safety gear to malfunction, which poses a safety risk. Summary of the Invention

[0005] To reduce the probability of safety clamp malfunction and lower safety risks, this application provides a double-lifting safety clamp.

[0006] The double-lifting safety clamp provided in this application adopts the following technical solution: A double-lifting safety clamp includes a clamp body and a pair of clamping blocks slidably disposed within the clamp body. The clamp body has jaws through which a guide rail passes. The clamping blocks are capable of abutting against the guide rail. A wedge-shaped block is disposed within the clamp body to abut against the clamping blocks. The clamping blocks are disposed between the guide rail and the wedge blocks. Each clamping block is provided with a lifting rod connected to an elevator speed limiting device. The lifting rod is used to move the clamping block when the elevator stalls. A reset component is disposed within the clamp body. The reset component is used to move the clamping blocks to reset.

[0007] By adopting the above technical solution, when the elevator stalls, the elevator speed limiting device drives the clamping block to move through the lifting rod. The clamping block moves under the abutment of the wedge block until it clamps and presses against the guide rail, thereby stopping the elevator. Each clamping block is pulled by the lifting rod to move, which reduces the probability of the safety gear malfunctioning when one side of the clamping block moves due to the car's uneven load, thereby reducing safety risks.

[0008] Preferably, the clamping block, wedge block and lifting rod are provided in two sets, the two sets of wedge blocks are inclined in opposite directions, and the two sets of lifting rods are provided on both sides of the clamp body.

[0009] By adopting the above technical solution, the existing one-way safety clamp structure can only be used for emergency stopping of the elevator in one direction. This application has two sets of clamping structures, thereby realizing bidirectional braking and improving applicability.

[0010] Preferably, the reset assembly includes a reset drive, an auxiliary reset block, an upper reset rod, and a lower reset rod. Two sets of the auxiliary reset block, upper reset rod, and lower reset rod are arranged on both sides of the guide rail. Two auxiliary reset grooves are provided on the inner wall of the clamp body. These grooves are located between two clamping blocks on the same side of the guide rail. The auxiliary reset block is slidably disposed within the auxiliary reset grooves. One end of the upper reset rod is rotatably connected to the auxiliary reset block, and the other end is rotatably connected to a clamping block located directly above the auxiliary reset block. One end of the lower reset rod is rotatably connected to the auxiliary reset block, and the other end is rotatably connected to a clamping block located directly below the auxiliary reset block. The reset drive is disposed within the clamp body and connected to the auxiliary reset block, and is used to drive the auxiliary reset block to move.

[0011] By adopting the above technical solution, when the safety clamp stops the elevator by clamping the guide rail, the reset drive component drives the two auxiliary reset blocks on the left and right to slide in the auxiliary reset slot. When the auxiliary reset blocks slide, the upper reset rod and the lower reset rod pull the clamping block on the same side of the guide rail to move and reset, thereby driving the four clamping blocks on both sides to move and reset. The operation is simple and convenient and easy to use.

[0012] Preferably, the reset assembly further includes a main reset block and a main reset rod. A main reset groove is provided vertically within the clamp body, and the main reset groove is located between two auxiliary reset grooves. The main reset block is slidably disposed in the main reset groove. One end of the main reset rod is rotatably connected to the main reset block, and the other end of the main reset rod is rotatably connected to the auxiliary reset block. The reset drive is a reset cylinder, which is disposed within the clamp body and located above the main reset block. The piston rod of the reset cylinder can abut against and push the main reset block to move.

[0013] By adopting the above technical solution, when a reset is required, the clamping block clamps the guide rail and drives the auxiliary reset block to slide close to the main reset block via the connecting rod. At the same time, the main reset block moves close to the reset cylinder. At this time, the reset cylinder is activated, and the piston rod of the reset cylinder pushes the main reset block to move. The movement of the main reset block drives the auxiliary reset block to move away from the main reset block via the main reset rod. During this process, the clamping block moves and resets via the upper and lower reset rods. The operation is simple and convenient. The reset is achieved by driving four clamping blocks through one reset cylinder, saving equipment costs.

[0014] Preferably, the clamp body has a bearing bracket between the wedge block and the clamping block, and multiple bearing rollers are rotatably mounted on the bearing bracket. The bearing rollers abut against the wedge block and the clamping block. The clamp body is provided with an assembly assembly, which assembles the bearing bracket onto the wedge block.

[0015] By adopting the above technical solution, the bearing roller reduces the friction force when the clamping block slides, which facilitates the sliding of the clamping block and improves the stability of the sliding of the clamping block.

[0016] Preferably, the assembly assembly includes an assembly plate and an assembly folding plate. The assembly plate is disposed on both sides of the wedge block and abuts against the bearing bracket from both sides. The assembly folding plate is disposed on the side of the assembly plate away from the wedge block and abuts against the side of the bearing bracket away from the wedge block. The side wall of the assembly folding plate away from the wedge block can slide against the clamping block.

[0017] By adopting the above technical solution, the bearing bracket is inserted into the area enclosed by the assembly plate, assembly folding plate and wedge block during assembly, which facilitates the overall disassembly and installation of the bearing, thereby facilitating maintenance and replacement.

[0018] Preferably, the assembly plate is provided with a T-shaped sliding block on the side away from the wedge block, and the side wall of the clamping block near the wedge block is inclined and provided with a T-shaped sliding groove, and the T-shaped sliding block is slidably inserted into the T-shaped sliding groove.

[0019] By adopting the above technical solution, the T-shaped sliding block is slidably inserted into the T-shaped sliding groove, and the clamping block and the assembly folding plate are slidably connected, thereby slidably connecting the clamping block to the wedge block, further improving the stability of the clamping block sliding.

[0020] Preferably, the clamp body is rotatably provided with two sets of swing arms, the swing arms are located on the side of the wedge block away from the clamping block, the wedge block is located on the swing arms, and a helical spring is provided between the swing arms.

[0021] By adopting the above technical solution, the helical spring pushes the swing arm to rotate, causing the swing arm to clamp the clamping block. When the clamping block slides to clamp the guide rail, the helical spring pushes the swing arm to clamp the clamping block, increasing the pressure of the clamping block against the guide rail. By increasing the friction, the stability of the safety clamp's clamping and stopping is further improved, reducing the safety risk of safety clamp failure.

[0022] Preferably, a limiting block is provided on the inner wall of the clamp body, the limiting block is disposed between the wedge block and the bearing bracket, and the limiting block can abut against the wedge block or the bearing bracket.

[0023] By adopting the above technical solution, the limiting block is used to abut against the bearing bracket and the wedge block, thereby limiting the rotation range of the swing arm, reducing the probability that excessive rotation of the swing arm will cause the clamping block to disengage from the space between the wedge blocks and cause the safety clamp to fail, and further reducing safety risks.

[0024] Preferably, the wedge block located on one side of the guide rail is provided with a spring seat connected to the helical spring, and the wedge block located on the other side of the guide rail is provided with a spring rod passing through the helical spring.

[0025] By adopting the above technical solution, the helical spring is set on the spring seat and spring rod, thereby improving the stability of the helical spring installation and the stability of the swing arm rotation.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. By setting up a clamp body, clamp jaws, clamping blocks, wedge blocks, lifting rods, and a reset assembly, when the elevator stalls, the speed limiting device drives the lifting rod to move, thereby pulling the clamping block to move. Under the limit of the wedge block, the clamping block clamps the elevator guide rail passing through the clamp body jaws, thus stopping the elevator. When the elevator needs to be restarted after stopping, the clamping block can be reset by the reset assembly after restarting the speed limiting device. Two lifting rods pull one clamping block to move respectively, reducing the probability of the safety clamp malfunctioning due to the movement of one clamping block on one side of the car under uneven load, thereby reducing safety risks. 2. By setting up a reset cylinder, auxiliary reset block, upper reset rod, lower reset rod, auxiliary reset groove, main reset block, main reset rod, and main reset groove, the reset cylinder is activated during reset to push the main reset block to slide in the main reset groove. This causes the auxiliary reset block to slide in the auxiliary reset groove via the main reset rod. In turn, the upper and lower reset rods drive the clamping blocks to slide and reset. The operation is simple and convenient, and the reset of four clamping blocks can be achieved with one cylinder, reducing equipment costs. 3. By setting up a bearing bracket, bearing rollers, assembly plate, and assembly folding plate, the bearing bracket is inserted into the space formed by the wedge block, assembly plate, and assembly folding plate, which facilitates disassembly and replacement. At the same time, the bearing rollers rotatably mounted on the bearing bracket abut against the wedge block and clamping block, thereby changing the friction mode between the wedge block and clamping block to rolling friction, reducing friction, and thus improving the stability and smoothness of the clamping block sliding. Attached Figure Description

[0027] Figure 1 This is an overall schematic diagram of a double-lifting safety clamp provided in an embodiment of this application.

[0028] Figure 2 This is a schematic diagram used to illustrate the internal structure of the clamp body.

[0029] Figure 3 yes Figure 2 A magnified view of region A in the middle.

[0030] Figure 4 This is a schematic diagram illustrating the structure of the reset component.

[0031] Explanation of reference numerals in the attached drawings: 1. Clamp body; 11. Clamp jaws; 12. Auxiliary groove; 121. Main reset groove; 122. Secondary reset groove; 2. Guide rail; 3. Clamping block; 31. Lifting rod; 32. T-shaped sliding groove; 4. Swing rod; 41. Wedge block; 42. Helical spring; 421. Spring seat; 422. Spring rod; 5. Reset assembly; 51. Reset cylinder; 52. Main reset block; 53. Main reset rod; 54. Secondary reset block; 55. Upper reset rod; 56. Lower reset rod; 6. Bearing bracket; 61. Bearing roller; 62. Limiting block; 7. Assembly assembly; 71. Assembly plate; 72. Assembly folding plate; 721. T-shaped sliding block. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0033] This application discloses a double-lifting safety clamp. (Refer to...) Figures 1 to 2The system includes a clamp body 1 and four right-angled trapezoidal clamping blocks 3. The clamp body 1 is fixed to the outer wall of the elevator car by welding or bolting. The clamp body 1 is made of high-strength metal materials such as cast steel or alloy steel, and has an internal cavity. The clamping blocks 3 are slidably disposed in the internal cavity of the clamp body 1 and are made of wear-resistant materials, such as special alloy cast iron or steel with a wear-resistant coating, to improve wear resistance and service life. The top of the clamp body 1 has a jaw 11 that connects to the cavity for the elevator guide rail 2 to pass through. The clamping blocks 3 are divided into two groups, with two clamping blocks 3 in each group disposed on both sides of the guide rail 2, with the inclined side of the clamping blocks 3 facing away from the guide rail 2. The two groups of clamping blocks 3 are symmetrically arranged. The clamp body 1 contains four wedge-shaped blocks 41 with inclined sidewalls. The inclined side of the wedge blocks 41 faces the guide rail 2 and slides against the inclined surface of the clamping blocks 3 away from the guide rail 2. Each clamping block 3 is fixedly equipped with a lifting rod 31 extending through the jaws 11. The lifting rod 31 is made of high-strength steel, possessing sufficient strength and toughness. The end of the lifting rod 31 away from the clamping block 3 is connected to the elevator speed limiting device to move the clamping block 3 relative to the clamping body 1 in the event of elevator stall. A reset assembly 5 is provided inside the housing for resetting the clamping block 3. Each clamping block is controlled by the lifting rod 31, reducing the possibility of accidental movement of a single clamping block causing malfunction of the safety clamp and lowering safety risks.

[0034] To improve clamping stability, refer to Figure 2 The clamp body 1 contains four swing arms 4 rotatably mounted via a pivot. Two swing arms 4 form a group, and the two groups are symmetrically arranged. In each group, two swing arms 4 are positioned on either side of the guide rail 2. The sidewall of the swing arm 4 closest to the guide rail 2 is fixedly connected to the sidewall of the wedge block 41 furthest from the guide rail 2. A helical spring 42 is installed between each group of swing arms 4. One swing arm 4 in each group has a spring seat 421 fixedly mounted on its sidewall for inserting the helical spring 42, and the other swing arm 4 has a spring rod 422 fixedly mounted on its sidewall for inserting the helical spring 42. Driven by the helical spring 42, the swing arms 4 rotate, causing the wedge block 41 to push the clamping block 3 against the guide rail 2, thereby improving clamping stability, reducing the probability of slippage after the elevator stops, and further reducing safety risks.

[0035] To improve the stability of the sliding of clamping block 3, refer to Figures 1 to 3One side wall of the clamp body 1 is openable and fixed by bolts or other means, allowing the internal cavity structure to be exposed for maintenance. Inside the clamp body 1, between the wedge block 41 and the clamping block 3, a bearing bracket 6 is disposed. The two sides of the bearing bracket 6 abut against the inner wall of the clamp body 1. The clamp body 1 is equipped with an assembly component 7, which assembles the bearing bracket 6 onto the wedge block 41. Multiple bearing rollers 61 are rotatably inserted into the bearing bracket 6, abutting against the wedge block 41 and the clamping block 3. The two sides of the bearing rollers 61 abut against the inner wall of the clamp body 1. The bearing rollers 61 can be pulled out and replaced from the side of the bearing bracket 6. A limiting block 62 is fixedly disposed on the inner wall of the clamp body 1, inserting between the bearing bracket 6 and the wedge block 41. The limiting block 62 abuts against either the wedge block 41 or the bearing bracket 6. The bearing rollers 61 are tumbling between the clamping block 3 and the wedge block 41, improving the stability and smoothness of the sliding of the clamping block 3.

[0036] For ease of disassembly and installation, please refer to... Figure 2 and Figure 3 Assembly component 7 includes assembly plate 71 and assembly folding plate 72. Assembly component 7 has two sets. Assembly plate 71 is fixed to the bottom and top walls of wedge block 41 by bolts and extends towards clamping block 3. Assembly folding plate 72 is fixed to the side wall of assembly plate 71 away from wedge block 41 and abuts against the side wall of bearing bracket 6 away from wedge block 41. The side wall of assembly folding plate 72 away from wedge block 41 can slide against clamping block 3. A T-shaped sliding block 721 is fixedly provided on the side of assembly folding plate 72 away from wedge block 41. A T-shaped sliding groove 32 is provided on the side wall of clamping block 3 near wedge block 41, allowing T-shaped sliding block 721 to slide into T-shaped sliding groove 32. After opening clamp body 1, bearing roller 61 can be pulled out from the side of bearing bracket 6. Simultaneously, bolts can be loosened to disassemble assembly plate 71, thereby disassembling clamping block 3 for maintenance and repair. The operation is simple and convenient.

[0037] For ease of use, please refer to Figure 2 and Figure 4The reset assembly 5 includes a reset cylinder 51, a main reset block 52, two main reset rods 53, two auxiliary reset blocks 54, two upper reset rods 55, and two lower reset rods 56. An auxiliary groove 12 is provided on the inner wall of the clamp body 1. The reset cylinder 51, as a reset driving component, is fixedly installed in the auxiliary groove 12. A main reset groove 121, communicating with the auxiliary groove, is provided vertically on the inner wall of the clamp body 1. The main reset block 52 is slidably installed in the main reset groove 121, positioned directly below the reset cylinder 51 and abutting against the piston rod of the reset cylinder 51. Auxiliary reset grooves 122 are provided horizontally on both sides of the main reset groove 121 on the inner wall of the clamp body 1. The auxiliary reset grooves 122 are located between the upper and lower sets of clamping blocks 3. The auxiliary reset blocks 54 are slidably installed in the auxiliary reset grooves 122. One end of the main reset rod 53 is rotatably mounted on the main reset block 52, and the other end is rotatably mounted on the auxiliary reset block 54. One end of the upper reset rod 55 is rotatably connected to the auxiliary reset block 54, and the other end of the upper reset rod 55 is rotatably connected to the clamping block 3 located directly above the auxiliary reset block 54. One end of the lower reset rod 56 is rotatably connected to the auxiliary reset block 54, and the other end of the lower reset rod 56 is rotatably connected to the clamping block 3 located directly below the auxiliary reset block 54. During reset, the reset cylinder 51 is activated to push the main reset block 52 downward. The main reset rod 53 drives the auxiliary reset block 54 to move away from the main reset block 52, thereby driving the clamping block 3 to move away from the guide rail 2 through the upper reset rod 55 and the lower reset rod 56, thus completing the reset.

[0038] The implementation principle of the double-lifting safety clamp in this application embodiment is as follows: When the elevator stalls, the elevator's speed limiting device is activated, driving the clamping blocks 3 to move via the lifting rod 31. Each clamping block 3 is connected to the speed limiting device via a lifting rod 31, reducing the possibility of a single clamping block 3 malfunctioning and causing the entire safety clamp to malfunction, thus reducing safety risks. During the movement of the clamping block 3, friction is reduced by the bearing roller 61, and the clamping block 3 slides and approaches the guide rail 2 under the limitation of the wedge block 41 until the clamping block 3 clamps the guide rail 2, completing the braking. In this application, corresponding braking components and lifting mechanisms are respectively set at the upper and lower ends of the clamp body 1, thereby realizing bidirectional braking of the elevator in both upward and downward directions. At the same time, the optimized contact structure and friction material between the clamping block 3 and the guide rail 2, as well as the reinforced overall structure, enable the safety clamp to provide greater braking force, shorten the braking distance, and ensure that the elevator can brake quickly and stably under various operating conditions. When a reset is required, simply activate the reset cylinder 51 to push the moved main reset block 52 to the bottom of the main reset groove 121, thereby driving the clamping block 3 to slide away from the guide rail 2 through the linkage structure. The operation is simple and convenient.

[0039] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A double-lifting safety clamp, characterized in that: The system includes a clamp body (1) and a pair of clamping blocks (3) slidably disposed within the clamp body (1). The clamp body (1) has jaws (11) through which a guide rail (2) passes. The clamping blocks (3) can abut against the guide rail (2). A wedge-shaped block (41) is disposed within the clamp body (1) to abut against the clamping blocks (3). The clamping blocks (3) are disposed between the guide rail (2) and the wedge-shaped block (41). Each clamping block (3) is provided with a lifting rod (31) connected to an elevator speed limiting device. The lifting rod (31) is used to move the clamping block (3) when the elevator stalls. A reset assembly (5) is disposed within the clamp body (1). The reset assembly (5) is used to move the clamping blocks (3) to reset. The reset assembly (5) includes a reset mechanism. The device comprises a drive unit, an auxiliary reset block (54), an upper reset rod (55), and a lower reset rod (56). Two sets of the auxiliary reset block (54), upper reset rod (55), and lower reset rod (56) are provided on both sides of the guide rail (2). The inner wall of the clamp body (1) is provided with two auxiliary reset grooves (122). The auxiliary reset grooves (122) are located between two clamping blocks (3) on the same side of the guide rail (2). The auxiliary reset block (54) is slidably disposed in the auxiliary reset groove (122). One end of the upper reset rod (55) is rotatably connected to the auxiliary reset block (54), and the other end of the upper reset rod (55) is rotatably connected to the clamping block (3) located directly above the auxiliary reset block (54). One end of the lower reset rod (56) is rotatably connected to the auxiliary reset block (54). The lower reset rod (56) is rotatably connected to the clamping block (3) located directly below the auxiliary reset block (54). The reset drive is located inside the clamp body (1) and connected to the auxiliary reset block (54). The reset drive is used to drive the auxiliary reset block (54) to move. The reset assembly (5) also includes a main reset block (52) and a main reset rod (53). A main reset groove (121) is provided in the clamp body (1) along the vertical direction. The main reset groove (121) is located between two auxiliary reset grooves (122). The main reset block (52) is slidably located in the main reset groove (121). One end of the main reset rod (53) is rotatably connected to the main reset block (52), and the other end of the main reset rod (53) is connected to the auxiliary reset block (54). The reset drive is a reset cylinder (51), which is located inside the clamp body (1) and above the main reset block (52). The reset cylinder (51) is located between two clamping blocks (3) at the same height. The piston rod of the reset cylinder (51) can abut against and push the main reset block (52) to move. The clamp body (1) is provided with a bearing bracket (6) between the wedge block (41) and the clamping block (3). Multiple bearing rollers (61) are rotatably arranged on the bearing bracket (6). The bearing rollers (61) abut against the wedge block (41) and the clamping block (3). The clamp body (1) is provided with an assembly assembly (7). The assembly assembly (7) assembles the bearing bracket (6) onto the wedge block (41).

2. The double-lifting safety clamp according to claim 1, characterized in that: The clamping block (3), wedge block (41) and lifting rod (31) are each provided in two sets. The two sets of wedge blocks (41) are inclined in opposite directions on their sidewalls, and the two sets of lifting rods (31) are provided on both sides of the clamp body (1).

3. The double-lifting safety clamp according to claim 1, characterized in that: The assembly component (7) includes an assembly plate (71) and an assembly folding plate (72). The assembly plate (71) is disposed on both sides of the wedge block (41) and abuts against the bearing bracket (6) from both sides. The assembly folding plate (72) is disposed on the side of the assembly plate (71) away from the wedge block (41) and abuts against the side of the bearing bracket (6) away from the wedge block (41). The sidewall of the assembly folding plate (72) away from the wedge block (41) can slide against the clamping block (3).

4. A double-lifting safety clamp according to claim 3, characterized in that: The assembly plate (72) is provided with a T-shaped sliding block (721) on the side away from the wedge block (41). The clamping block (3) is inclined on the side wall near the wedge block (41) and is provided with a T-shaped sliding groove (32). The T-shaped sliding block (721) is slidably inserted into the T-shaped sliding groove (32).

5. A double-lifting safety clamp according to claim 1, characterized in that: Two sets of swing arms (4) are rotatably arranged inside the clamp body (1). The swing arms (4) are arranged on the side of the wedge block (41) away from the clamping block (3). The wedge block (41) is arranged on the swing arms (4). A helical spring (42) is arranged between the swing arms (4).

6. A double-lifting safety clamp according to claim 5, characterized in that: The inner wall of the clamp body (1) is provided with a limiting block (62), which is located between the wedge block (41) and the bearing bracket (6). The limiting block (62) can abut against the wedge block (41) or the bearing bracket (6).

7. A double-lifting safety clamp according to claim 5, characterized in that: The wedge block (41) located on one side of the guide rail (2) is provided with a spring seat (421) connected to the helical spring (42), and the wedge block (41) located on the other side of the guide rail (2) is provided with a spring rod (422) passing through the helical spring (42).

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