Leakage-proof valve for fire extinguisher

Abstract

The utility model discloses a leak-proof valve for a fire extinguisher. The leak-proof valve comprises the fire extinguisher, a pressing handle, a lifting handle and a nozzle are arranged on the fire extinguisher, a connecting seat is fixedly mounted on the lifting handle, a protective structure is mounted on the connecting seat, two arc-shaped supporting rods are mounted on the protective structure, and an abutting structure is mounted on the two arc-shaped supporting rods; according to the fire extinguisher, one side of the nozzle can be shielded and protected by utilizing the dustproof cover plate, so that blockage of the nozzle caused by dust accumulation in the nozzle in the long-term placement process of the fire extinguisher is avoided, and the normal use of the fire extinguisher is ensured; when the fire extinguisher is used, limitation on the pressing plate can be relieved, then the hand is supported below the pressing plate, the fire extinguisher is lifted upwards, the pressing plate is extruded to be overturned in the process, the dustproof cover plate is overturned in the overturning process of the pressing plate, the nozzle is opened, the nozzle can be used for spraying normally, and operation is easy and fast.

Description

Technical Field

[0001] The utility model relates to the technical field of fire extinguishers, in particular to a leakage-proof valve for fire extinguishers. Background Art

[0002] The fire extinguisher valve is a key component on the fire extinguisher, used to control the release of the fire extinguishing agent. It is mainly composed of the valve body, valve core, lifting handle, pressure handle, nozzle and other components. When the fire extinguisher needs to be used, press the pressure handle down so that the pressure handle presses against the valve core to open the valve, so that the fire extinguishing agent is sprayed out from the inside of the fire extinguisher, thereby extinguishing the fire.

[0003] In the prior art, if a fire extinguisher is placed in a dusty environment for a long time, dust is easy to enter and accumulate on the nozzle on the valve, causing the nozzle to be blocked, affecting the spraying use of the fire extinguisher. If the fire extinguisher is placed for too long, the pressure handle on the valve is prone to aging and loosening. If it is accidentally touched, it is easy to press against the valve core and cause leakage. Therefore, a leak-proof valve is needed for a fire extinguisher to meet people's needs. Utility Model Content

[0004] The utility model aims to provide a leakage-proof valve for a fire extinguisher to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the utility model provides the following technical solution: a fire extinguisher anti-leakage valve, comprising a fire extinguisher; the fire extinguisher is provided with a pressure handle, a lifting handle and a nozzle, a connecting seat is fixedly installed on the lifting handle, a protective structure is installed on the connecting seat, two arc-shaped support rods are installed on the protective structure, a pressing structure is installed on the two arc-shaped support rods, two threaded seats are installed on the pressing structure, and a limiting structure is installed on the two threaded seats;

[0006] The protective structure includes two linkage rods, which are rotatably installed on both sides of the connecting seat respectively, and the same pressure plate is fixedly installed on the two linkage rods. A connecting rod is rotatably installed on one end of the two linkage rods, and a guide seat and an L-shaped movable rod are movably installed on the two connecting rods. The two guide seats are fixedly installed on the nozzle, and the same fixed seat is rotatably installed on the two L-shaped movable rods. The fixed seat is fixedly installed on the nozzle, and the same dust cover is fixedly installed on one end of the two L-shaped movable rods, and the dust cover is in contact with one side of the nozzle.

[0007] Preferably, the pressing structure includes a pressing slider, which is slidably mounted on the side where two arc-shaped struts are close to each other, and the two arc-shaped struts are respectively fixedly mounted on both sides of the pressure plate. A pressing screw is threadedly mounted on the pressing slider, and a rubber pressing block is fixedly mounted on one end of the pressing screw, and the rubber pressing block is in contact with one side of the pressure handle.

[0008] Preferably, a threaded adjustment hole is provided on the inner wall of the pressure sliding block, and the pressure screw rod is threadably installed in the threaded adjustment hole.

[0009] Preferably, an arc-shaped guide groove is provided on one side of the arc-shaped support rod, an arc-shaped slider is slidably installed in the arc-shaped guide groove, and the arc-shaped slider is fixedly installed on one side of the pressing slider.

[0010] Preferably, the limiting structure includes a positioning seat, which is fixedly mounted on one side of the pressing slider, and a positioning screw is movably mounted on the inner wall of the positioning seat. The positioning screw passes through the positioning seat and is threadedly mounted on a threaded seat, and the threaded seat is fixedly mounted on one side of the arc support rod.

[0011] Preferably, a rotating shaft hole is opened on the inner wall of the fixing seat, and a connecting shaft is rotatably installed in the rotating shaft hole. The connecting shaft is fixedly installed on the side where the two L-shaped movable rods are close to each other. A torsion spring is fixedly sleeved on the connecting shaft, and one end of the torsion spring is fixedly installed on the inner wall of the rotating shaft hole, and the other end of the torsion spring is fixedly installed on the connecting shaft.

[0012] Preferably, a linkage groove is provided on the L-shaped movable rod, and a guide slide hole is provided on the guide seat. The linkage groove is adapted to the guide slide hole. The same linkage shaft is movably installed in the linkage groove and the guide slide hole. The linkage shaft is rotatably installed on the connecting rod. The linkage groove and the guide slide hole both correspond to the rotating shaft hole.

[0013] Preferably, an arc-shaped limit rod is fixedly installed on the handle, a stop block is fixedly installed on one end of the arc-shaped limit rod, an arc-shaped sliding hole is opened on the pressure plate, the arc-shaped limit rod is slidably installed in the arc-shaped sliding hole, a spring is slidably sleeved on the arc-shaped limit rod, one end of the spring is fixedly installed on the handle, and the other end of the spring is fixedly installed on one side of the pressure plate.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] (1) The utility model utilizes a dust cover to shield and protect one side of the nozzle, thereby preventing dust from accumulating in the nozzle and causing clogging of the nozzle during long-term storage of the fire extinguisher, thereby ensuring the normal use of the fire extinguisher. When in use, it is only necessary to rotate and pull the positioning screw to remove it from the threaded seat and the positioning seat to release the restriction on the pressure plate, and then place your hand under the pressure plate and lift the fire extinguisher upward. During the process, the pressure plate will be squeezed and flipped. During the flipping of the pressure plate, the dust cover will flip and open the nozzle, so that the nozzle can be used for normal spraying. The operation is simple and quick.

[0016] (2) By rotating the pressing screw, the rubber pressing block can be pressed against the pressure handle to support the pressure handle and prevent the pressure handle from being in a loose state. The pressing strength of the rubber pressing block can be adjusted according to the looseness of the pressure handle to prevent the pressure handle from accidentally touching the valve core due to looseness and causing leakage. At the same time, the pressure plate will also be affected by the rubber pressing block, making it impossible for the pressure handle and the pressure plate to move. When in use, only the positioning screw needs to be pulled out from the threaded seat and the positioning seat to release the restrictions on the pressure handle and the pressure plate at the same time, so that a fire extinguisher can be used to spray and extinguish the fire. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a three-dimensional structural diagram of the anti-leakage valve for fire extinguishers proposed by the utility model;

[0018] Figure 2 This is a side structural schematic diagram of the anti-leakage valve for a fire extinguisher proposed by the utility model;

[0019] Figure 3 A schematic diagram of the connection structure of the linkage rod part of the anti-leakage valve for the fire extinguisher proposed by the utility model;

[0020] Figure 4 It is a cross-sectional structural diagram of the pressure plate and the fixing seat of the anti-leakage valve for the fire extinguisher proposed by the utility model;

[0021] Figure 5 This is a schematic structural diagram of the linkage shaft portion of the anti-leakage valve for a fire extinguisher proposed by the utility model;

[0022] Figure 6 The utility model is a schematic structural diagram of the arc-shaped support rod part of the anti-leakage valve for the fire extinguisher.

[0023] In the figure: 1. fire extinguisher; 2. pressure handle; 3. lifting handle; 4. nozzle; 5. connecting seat; 51. linkage rod; 52. pressure plate; 53. connecting rod; 54. guide seat; 55. L-shaped movable rod; 56. fixed seat; 57. dust cover; 58. rotating shaft hole; 59. connecting shaft; 510. torsion spring; 511. linkage groove; 512. guide sliding hole; 513. linkage shaft; 514. arc-shaped limit rod; 515. block; 516. arc-shaped sliding hole; 517. spring; 6. arc-shaped support rod; 61. pressing slider; 62. pressing screw rod; 63. rubber block; 64. threaded adjustment hole; 65. arc-shaped guide groove; 66. arc-shaped slider; 7. threaded seat; 71. positioning seat; 72. positioning screw. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] Example 1: Please refer to Figure 1-6 The utility model provides a technical solution: a fire extinguisher anti-leakage valve, comprising a fire extinguisher 1; the fire extinguisher 1 is provided with a pressure handle 2, a lifting handle 3 and a nozzle 4, a connecting seat 5 is fixedly installed on the lifting handle 3, a protective structure is installed on the connecting seat 5, two arc-shaped support rods 6 are installed on the protective structure, a pressing structure is installed on the two arc-shaped support rods 6, two threaded seats 7 are installed on the pressing structure, and a limiting structure is installed on the two threaded seats 7;

[0026] The protective structure includes two linkage rods 51, which are rotatably mounted on both sides of the connecting seat 5, and the same pressing plate 52 is fixedly mounted on the two linkage rods 51. A connecting rod 53 is rotatably mounted on one end of the two linkage rods 51. A guide seat 54 and an L-shaped movable rod 55 are movably mounted on the two connecting rods 53. The two guide seats 54 are fixedly mounted on the nozzle 4. The same fixed seat 56 is rotatably mounted on the two L-shaped movable rods 55. The fixed seat 56 is fixedly mounted on the nozzle 4. The same dust cover 57 is fixedly mounted on one end of the two L-shaped movable rods 55. The dust cover 57 is in contact with one side of the nozzle 4. The dust cover 57 can be used to block one side of the nozzle 4. To prevent dust from entering the nozzle 4 and causing blockage of the nozzle 4 during the placement of the fire extinguisher 1, when the restriction on the pressure plate 52 is released, place your hand under the pressure plate 52 and lift the fire extinguisher 1 upward for use. During the process, the pressure plate 52 will be squeezed by the hand and drive the two linkage rods 51 to flip on the connecting seat 5. At the same time, the flipped pressure plate 52 will cause the linkage shaft 513 to move to the end of the linkage groove 511. At this time, the linkage shaft 513 and the connecting shaft 59 are in a straight line. Under the action of the torsion spring 510, the connecting shaft 59 is driven to rotate. The rotating connecting shaft 59 will drive the two L-shaped movable rods 55 to flip upward, so that the flipped L-shaped movable rod 55 drives the dust cover 57 to flip upward and open the nozzle 4.

[0027] In order to enable the dust cover 57 to be flipped and opened according to usage requirements, a rotating shaft hole 58 is opened on the inner wall of the fixed seat 56, and a connecting shaft 59 is rotatably installed in the rotating shaft hole 58. The connecting shaft 59 is fixedly installed on the side where the two L-shaped movable rods 55 are close to each other. A torsion spring 510 is fixedly sleeved on the connecting shaft 59, one end of the torsion spring 510 is fixedly installed on the inner wall of the rotating shaft hole 58, and the other end of the torsion spring 510 is fixedly installed on the connecting shaft 59. When the L-shaped movable rod 55 is no longer pulled by the linkage shaft 513 on the connecting rod 53, the compressed torsion spring 510 will be released and drive the connecting shaft 59 to rotate, and the rotating connecting shaft 59 will rotate in the rotating shaft hole 58 on the fixed seat 56. The continuously rotating connecting shaft 59 will drive the two L-shaped movable rods 55 to flip upward, so that the flipped L-shaped movable rod 55 drives the dust cover 57 to flip upward and open the nozzle 4.

[0028] In order to prevent the dust cover 57 from loosening from the front of the nozzle 4, a linkage groove 511 is provided on the L-shaped movable rod 55, and a guide slide hole 512 is provided on the guide seat 54. The linkage groove 511 is adapted to the guide slide hole 512. The linkage groove 511 and the guide slide hole 512 are movably installed with the same linkage shaft 513. The linkage shaft 513 is rotatably installed on the connecting rod 53. The linkage groove 511 and the guide slide hole 512 are both corresponding to the shaft hole 58. The L-shaped movable rod 55 is pulled by the connecting rod 53 and the linkage shaft 513 and its angle is limited, so that the dust cover 57 can always The nozzle 4 is blocked in front and one side of the nozzle 4 can be blocked and protected by the dust cover 57. The flipped linkage rod 51 will drive one end of the connecting rod 53 to flip and move, so that the other end of the connecting rod 53 rotates on the linkage shaft 513 and pushes the linkage shaft 513 to move. The moving linkage shaft 513 will move in the guide slide hole 512 and the linkage groove 511. When the linkage shaft 513 moves to the end of the linkage groove 511, the linkage shaft 513 and the connecting shaft 59 are in a straight line, and the torsion spring 510 in a compressed state will be released and drive the connecting shaft 59 to rotate.

[0029] The handle 3 is provided with an arc-shaped limit rod 514, one end of which is fixedly provided with a stopper 515. The pressure plate 52 is provided with an arc-shaped sliding hole 516, and the arc-shaped limit rod 514 is slidably installed in the arc-shaped sliding hole 516. A spring 517 is slidably sleeved on the arc-shaped limit rod 514, one end of which is fixedly provided on the handle 3, and the other end of the spring 517 is fixedly provided on one side of the pressure plate 52. When the user places his hand under the pressure plate 52 and lifts the fire extinguisher 1 upward for use, the pressure plate 52 will be squeezed by the hand and drive the two linkage rods 51 to flip on the connecting seat 5. At the same time, the flipped pressure plate 52 will slide on the arc-shaped limit rod 514 through the arc-shaped sliding hole 516 and squeeze the spring 517, thereby preventing the pressure plate 52 from deflecting. By setting the stopper 515, the pressure plate 52 can be prevented from slipping off the arc-shaped limit rod 514.

[0030] The working principle is as follows: by rotating the pressing screw rod 62, the rubber pressing block 63 can be driven to press on the pressing handle 2 through the cooperation with the threaded adjustment hole 64, so that the pressing handle 2 and the pressing plate 52 are stretched and pressed, so that the pressing plate 52 and the pressing handle 2 cannot move, so as to avoid accidental contact with the valve core due to the loosening of the pressing handle 2, and the pressing screw rod 62 can be rotated to adjust the pressing strength of the rubber pressing block 63 according to the loosening degree of the pressing handle 2. At the same time, the L-shaped movable rod 55 is pulled by the connecting rod 53 and the linkage shaft 513 and its angle is limited, so that the dust cover plate 57 can always cover the front of the nozzle 4. The dust cover plate 57 can be used to block and protect one side of the nozzle 4 to prevent dust from entering the nozzle 4 and clogging the nozzle 4 during the placement of the fire extinguisher 1. At this time, the rotating shaft The hole 58 is in a compressed state. When in use, the positioning screw 72 is rotated to screw it out of the threaded seat 7, and then the positioning screw 72 is pulled out from the positioning seat 71, so that the pressure slider 61 and the arc support rod 6 are in a movable state, and the rubber stop block 63 is no longer tightly pressed on the pressure handle 2. At this time, the restriction on the pressure plate 52 and the pressure handle 2 can be released, and then the hand is supported under the pressure plate 52 and the fire extinguisher 1 is lifted up for use. During the process, the pressure plate 52 will be squeezed by the hand and drive the two linkage rods 51 to flip on the connecting seat 5. At the same time, the flipped pressure plate 52 will slide on the arc limit rod 514 through the arc sliding hole 516 and squeeze the spring 517, thereby preventing the pressure plate 52 from deviating. By setting the stop block 515, the pressure plate 52 can be prevented from moving away from the arc The movable linkage shaft 513 moves in the guide sliding hole 512 on the guide seat 54, thereby limiting the moving direction of the linkage shaft 513. At the same time, the movable linkage shaft 513 moves in the linkage groove 511 on the L-shaped movable rod 55. When the linkage shaft 513 moves to the end of the linkage groove 511, the linkage shaft 513 and the connecting shaft 59 are in a straight line, and the L-shaped movable rod 55 is no longer pulled by the linkage shaft 513 on the connecting rod 53. The compressed torsion spring 510 is released and drives the connecting shaft 59 to rotate. The shaft 59 will rotate in the shaft hole 58 on the fixed seat 56, so as to achieve the rotation effect. The continuously rotating connecting shaft 59 will drive the two L-shaped movable rods 55 to flip upward, so that the flipped L-shaped movable rod 55 drives the dust cover plate 57 to flip upward and open the nozzle 4. When spraying, the pressure handle 2 is pressed downward. The movement of the pressure handle 2 and the pressure plate 52 will squeeze the rubber block 63 and the arc-shaped support rod 6 respectively. Since the pressure slider 61 and the arc-shaped support rod 6 are in an active state at this time, the rubber block 63 will drive the pressure slider 61 to slide through the pressure screw 62 when being squeezed. The sliding pressure slider 61 will drive the two arc-shaped sliders 66 to slide in the two arc-shaped guide grooves 65 respectively. The continuously pressed pressure handle 2 will pass between the two arc-shaped support rods 6.Thus, the pressing plate 52 and the pressing handle 2 are no longer restricted by the rubber stopper 63 and the arc support rod 6, so that the spraying operation can be performed. When the hand is released from the pressing plate 52, the compressed spring 517 will push the pressing plate 52 and the linkage rod 51 to flip and reset, so that the linkage rod 51 pulls the connecting rod 53 to move and reset, and the connecting rod 53 pulls the linkage shaft 513 to slide and reset in the guide slide hole 512. The linkage shaft 513 will drive the L-shaped movable rod 55 to flip and reset through the linkage groove 511, so that the dust cover 57 will cover the nozzle 4 again.

[0031] Example 2: Figure 1-6 In order to avoid the situation that the valve core is accidentally touched by the loose pressure handle 2 and leakage occurs, a pressure structure is arranged on the arc support rod 6, and a limiting structure is arranged on the threaded seat 7. The pressure structure includes a pressure slider 61, which is slidably installed on the side where the two arc support rods 6 are close to each other. The two arc support rods 6 are fixedly installed on both sides of the pressure plate 52, and a pressure screw rod 62 is threadedly installed on the pressure slider 61. A rubber pressure block 63 is fixedly installed on one end of the pressure screw rod 62. The rubber pressure block 63 contacts one side of the pressure handle 2. A threaded adjustment hole 64 is provided on the inner wall of the pressure slider 61. The pressure screw rod 62 is threadedly installed in the threaded adjustment hole 64. An arc guide groove 65 is provided on one side of the arc support rod 6. An arc slider 66 is slidably installed in the arc guide groove 65. The arc slider 66 is fixedly installed on one side of the pressure slider 61. The limiting structure includes a positioning seat 71, and the positioning seat 71 is fixedly installed on the pressure slider 61. The cam 72 is then pulled out of the positioning seat 71 to allow the positioning screw 72 to penetrate the positioning seat 71 and be threadedly mounted on the threaded seat 7. The threaded seat 7 is fixedly mounted on one side of the arc support rod 6. By rotating the pressing screw 62, it can drive the rubber stopper 63 to press on the pressure handle 2 through the cooperation with the threaded adjustment hole 64, so as to open and press the pressure handle 2 and the pressure plate 52, so that the pressure plate 52 and the pressure handle 2 cannot move, thereby avoiding accidental contact with the valve core due to the loosening of the pressure handle 2. The pressing screw 62 can be rotated to adjust the pressure of the rubber stopper 63 according to the loosening degree of the pressure handle 2. The positioning screw 72 is rotated to screw it out of the threaded seat 7, and then the positioning screw 72 is pulled to withdraw it from the positioning seat 71, so that the pressure slider 61 and the arc support rod 6 are in a movable state, and the rubber stopper 63 is no longer tightly pressed on the pressure handle 2. At this time, the restriction on the pressure plate 52 and the pressure handle 2 can be released. The remaining features are the same as those in Example 1.

[0032] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fire extinguisher anti-leakage valve, comprising a fire extinguisher (1); characterized in that: The fire extinguisher (1) is provided with a pressure handle (2), a lifting handle (3) and a nozzle (4); a connecting seat (5) is fixedly mounted on the lifting handle (3); a protective structure is mounted on the connecting seat (5); two arc-shaped support rods (6) are mounted on the protective structure; a pressing structure is mounted on the two arc-shaped support rods (6); two threaded seats (7) are mounted on the pressing structure; and a limiting structure is mounted on the two threaded seats (7); The protective structure comprises two linkage rods (51), the two linkage rods (51) are rotatably mounted on both sides of the connecting seat (5), the same pressing plate (52) is fixedly mounted on the two linkage rods (51), one end of each linkage rod (51) is rotatably mounted with a connecting rod (53), each connecting rod (53) is movably mounted with a guide seat (54) and an L-shaped movable rod (55), the two guide seats (54) are fixedly mounted on the nozzle (4), the two L-shaped movable rods (55) are rotatably mounted with the same fixed seat (56), the fixed seat (56) is fixedly mounted on the nozzle (4), and one end of each L-shaped movable rod (55) is fixedly mounted with the same dust cover plate (57), the dust cover plate (57) is in contact with one side of the nozzle (4).

2. The anti-leakage valve for fire extinguisher according to claim 1, characterized in that: The pressing structure comprises a pressing slider (61), the pressing slider (61) being slidably mounted on a side where two arc-shaped support rods (6) are close to each other, the two arc-shaped support rods (6) being fixedly mounted on two sides of the pressure plate (52), respectively, a pressing screw rod (62) being threadedly mounted on the pressing slider (61), a rubber pressing block (63) being fixedly mounted on one end of the pressing screw rod (62), and the rubber pressing block (63) being in contact with one side of the pressure handle (2).

3. The anti-leakage valve for fire extinguisher according to claim 2, characterized in that: The inner wall of the pressing sliding block (61) is provided with a threaded adjustment hole (64), and the pressing screw rod (62) is threadedly installed in the threaded adjustment hole (64).

4. The anti-leakage valve for fire extinguisher according to claim 1, characterized in that: An arc-shaped guide groove (65) is provided on one side of the arc-shaped support rod (6), and an arc-shaped slider (66) is slidably mounted in the arc-shaped guide groove (65). The arc-shaped slider (66) is fixedly mounted on one side of the pressing slider (61).

5. The anti-leakage valve for fire extinguisher according to claim 1, characterized in that: The limiting structure comprises a positioning seat (71), the positioning seat (71) is fixedly mounted on one side of the pressing slider (61), a positioning screw (72) is movably mounted on the inner wall of the positioning seat (71), the positioning screw (72) passes through the positioning seat (71) and is threadedly mounted on a threaded seat (7), and the threaded seat (7) is fixedly mounted on one side of the arc-shaped support rod (6).

6. The anti-leakage valve for fire extinguisher according to claim 1, characterized in that: The inner wall of the fixing seat (56) is provided with a rotating shaft hole (58), a connecting shaft (59) is rotatably mounted in the rotating shaft hole (58), the connecting shaft (59) is fixedly mounted on the side of the two L-shaped movable rods (55) close to each other, a torsion spring (510) is fixedly sleeved on the connecting shaft (59), one end of the torsion spring (510) is fixedly mounted on the inner wall of the rotating shaft hole (58), and the other end of the torsion spring (510) is fixedly mounted on the connecting shaft (59).

7. The anti-leakage valve for fire extinguisher according to claim 1, characterized in that: The L-shaped movable rod (55) is provided with a linkage groove (511), and the guide seat (54) is provided with a guide sliding hole (512). The linkage groove (511) and the guide sliding hole (512) are adapted to each other. A linkage shaft (513) is movably installed in the linkage groove (511) and the guide sliding hole (512). The linkage shaft (513) is rotatably installed on the connecting rod (53). The linkage groove (511) and the guide sliding hole (512) both correspond to the rotating shaft hole (58).

8. The anti-leakage valve for fire extinguisher according to claim 1, characterized in that: An arc-shaped limit rod (514) is fixedly mounted on the handle (3), a stopper (515) is fixedly mounted on one end of the arc-shaped limit rod (514), an arc-shaped sliding hole (516) is opened on the pressure plate (52), the arc-shaped limit rod (514) is slidably mounted in the arc-shaped sliding hole (516), a spring (517) is slidably sleeved on the arc-shaped limit rod (514), one end of the spring (517) is fixedly mounted on the handle (3), and the other end of the spring (517) is fixedly mounted on one side of the pressure plate (52).

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