High-reliability automatic puncturing and exhausting device for green tire blank

Abstract

The utility model belongs to the technical field of tire production equipment, and discloses a high-reliability automatic puncturing and exhausting device for a green tire blank. A puncturing plate of the device is horizontally fixed to one side of a rack, a supporting roller and a driving roller are arranged on the two sides of the puncturing plate in parallel, and the supporting roller and the driving roller are in rotating connection and driving connection with the rack respectively; the needling mechanism is arranged on the rack above the pricking plate, a plurality of pricking needles are fixed to the bottom of the needling mechanism in the length direction, and the needling mechanism can drive the pricking needles to prick into the receding holes in an up-down reciprocating mode; the pressing mechanism is arranged on the rack above the driving roller; parallel guide rollers are rotationally arranged at the bottom of the pressing mechanism; and the pressing mechanism can drive the guide rollers to be close to the driving roller in an up-and-down reciprocating manner. The puncturing plate, the supporting roller and the driving roller are arranged on the lower portion of the machine frame in a rotating mode, the puncturing mechanism and the pressing mechanism which can reciprocate up and down are arranged on the upper portion of the machine frame, automatic rotation of a green tire blank and puncturing of exhaust holes can be achieved, and the automatic rotating puncturing machine has the advantages of being simple in structure, safe, reliable, stable in puncturing and low in labor intensity.

Description

TECHNICAL FIELD

[0001] The utility model relates to tire production equipment technical field, concretely relates to a kind of high reliability automatic puncture exhaust device for tire green tire blank with simple structure, safe and reliable, stab, low labor intensity. BACKGROUND

[0002] Green tire blank is the tire manufacturing process that rubber and other raw materials are processed through a series of processes, form the shape and size of certain tire prototype, also is the basis of subsequent processing and vulcanization of tire. Because of the production process, unvulcanized tire green tire blank is formed by a plurality of layers of fiber cord layer or steel cord layer and so on semi-finished product and several rubber sheet, so it is inevitable to be mixed with air in each semi-finished product and in the process of each layer, and the mixed air will lead to blister and delamination phenomenon in the process of tire blank vulcanization, thereby affecting the qualified rate of tire, so it is necessary to exhaust the air mixed in each layer and between each layer.

[0003] At present, after tire green tire blank is pasted, it is generally rolled repeatedly by molding equipment to the tire blank, and then the operator checks the appearance of the tire embryo, when the air bubble between layers is not completely exhausted, the air is exhausted by artificial puncturing. However, artificial puncturing exhaust not only has low production efficiency, but also is limited by the experience and attitude of operator, and the puncturing interval is scattered, thereby affecting the exhaust effect and appearance after vulcanization. Especially for the mixed air such as joint lap joint part, it is difficult to detect on appearance after molding, so it is difficult to completely exhaust the mixed air in green tire blank by artificial puncturing, so that the qualified rate of tire blank after vulcanization is difficult to improve effectively.

[0004] In the prior art, in order to solve the problem of air inclusion in the tire blank, a feeding mechanism such as a conveying belt and a conveying roller is arranged, and then a roller with a needle is matched to roll and press the semi-finished products such as the strip-shaped tread, the sidewall, the supporting rubber, and the tire body, so as to discharge the air inclusion therein. However, due to the structure, it is difficult to apply the needle punching and air discharging to the formed annular tire blank. Therefore, a support roller connected with a driving device is arranged at the lower part of the frame, and a needle roller with a plurality of needles arranged in the circumferential direction and connected with a lifting cylinder is arranged above the support roller, so that the annular tire blank can be roll-pressed and punched to discharge air by the cooperation of the support roller and the needle roller. However, the support roller needs to be supported and connected at both ends, so that it is difficult to replace the annular tire blank, the punching efficiency is low, and the surface of the tire blank is easily scratched when the needle is rotated with the needle roller during the roll pressing and punching, so as to affect the quality of the tread after vulcanization. In addition, the patent CN220719611U submitted by the applicant arranges a liftable cantilever-shaped support seat connected with a linear driving device at the lower part of the frame, and arranges a support roller and a punching plate on the support seat, and arranges a cantilever-shaped needle seat with a plurality of needles and capable of reciprocating up and down through an eccentric transmission mechanism at the upper part, so that the tire blank can be driven to rotate automatically by the cooperation of the support roller and the driving roller, and the reciprocating cantilever-shaped needle seat driven by the eccentric transmission mechanism can punch and discharge air on the tire blank, so as to finally realize the automatic rotation and punching of the tire blank. Although the above-mentioned patent solves the problems of difficulty in replacing the annular tire blank and easy scratching of the surface of the tire blank, and has high punching and air discharging efficiency, the vibration of the eccentric transmission mechanism is obvious during work, which not only causes large working noise, but also causes the abrasion of the rotating parts to be intensified, so that the failure rate during work is high and the working stability is poor. Practical new type content

[0005] In view of the deficiencies in the prior art, the present practical new type provides a high-reliability automatic punching and air discharging device for tire blank, which has simple structure, safety and reliability, stable needle, and low labor intensity.

[0006] The present practical new type is implemented as follows: a frame, a punching plate, a support roller, a driving roller, a driving motor, a needle punching mechanism, and a pressing mechanism are arranged. The punching plate is cantilever-shaped and horizontally fixed on one side of the frame, and a clearance hole is arranged in the middle of the punching plate along the length direction. The driving motor is fixedly arranged on the frame. The support roller and the driving roller are respectively arranged in parallel on both sides of the punching plate. One end of the support roller is rotationally connected with the frame. One end of the driving roller is connected with the driving shaft of the driving motor.

[0007] The needle punching mechanism is arranged on the frame above the punching plate. A plurality of downward extending needles are fixedly arranged on the bottom of the needle punching mechanism along the length direction of the punching plate. The needle punching mechanism can drive the needles on the bottom to reciprocate up and down and penetrate into the clearance hole.

[0008] The pressing mechanism is arranged on the frame above the driving roller, the bottom of the pressing mechanism is rotatably provided with a guide roller parallel to the driving roller, and the pressing mechanism can drive the guide roller at the bottom to reciprocatingly move up and down to approach the driving roller.

[0009] Further, the needling mechanism further comprises a needle seat and a needle straight-line driving device, the needle straight-line driving device is vertically fixed on the frame, the needle seat is arranged above the punching plate in parallel, the top of the needle seat is connected with a driving rod of the needle straight-line driving device, and the lower end of the needle seat is spaced apart in the length direction and provided with a plurality of downward extending needles.

[0010] Further, the needle straight-line driving device further comprises a needle guide rod and a needle guide sleeve, two needle guide sleeves are respectively vertically fixed on the frame on the two sides of the needle straight-line driving device, and the needle guide rod is respectively vertically fixed on the two sides of the driving rod at the length direction of the needle seat and respectively slidably penetrates through the corresponding needle guide sleeve.

[0011] Further, the needle seat comprises a fixed seat and a movable seat, the fixed seat is an inverted "L" shaped long strip plate, the top end of the fixed seat is connected with the driving rod of the needle straight-line driving device, the inner side of the fixed seat is vertically provided with a plurality of grooves penetrating through the lower end surface in the length direction to accommodate the needles, and the movable seat is detachably embedded in the inner side of the fixed seat and the inner side of the movable seat abuts against the needles in the grooves.

[0012] Further, the upper surface of the punching plate is a circular arc surface, and the top ends of the supporting roller and the driving roller are located on the extension line of the circular arc surface of the punching plate.

[0013] Further, the pressing mechanism further comprises a pressing straight-line driving device and a pressing support, the pressing straight-line driving device is fixedly arranged on the frame, the pressing support is arranged above the driving roller and the top end of the pressing support is connected with the driving rod of the pressing straight-line driving device, and the guide roller is arranged at the lower end of the pressing support and rotatably connected with the pressing support at both ends.

[0014] Further, the pressing support is an "L" shaped support with an opening downward, and the guide roller is embedded in the opening, and both ends of the guide roller are rotatably connected with the inner side of the corresponding opening of the pressing support.

[0015] Further, the pressing mechanism further comprises a pressing guide rod and a pressing guide sleeve, two pressing guide sleeves are respectively fixedly arranged on the frame on the two sides of the pressing straight-line driving device, and the pressing guide rod is respectively fixedly arranged at the length direction of the pressing support close to both ends and respectively slidably penetrates through the corresponding pressing guide sleeve.

[0016] Further, the pressing mechanism further comprises a guide frame, which is arranged between the pressing linear driving device and the pressing support, is parallel to the pressing support, and is fixedly connected to the rack at one end, the pressing guide sleeve is fixedly arranged on the guide frame, the guide frame is provided with a through hole between the two pressing guide sleeves, and the driving rod of the pressing linear driving device is movably penetrated through the through hole on the guide frame and is fixedly connected to the pressing support.

[0017] Further, the pressing guide sleeve is fixedly arranged at the end of the guide frame away from the pressing support, the pressing guide rod is a T-shaped rod, and the pressing guide rod is provided with a reset spring, the ends of which are respectively abutted against the end of the pressing guide rod and the end surface of the pressing guide sleeve.

[0018] The utility model discloses beneficial effects:

[0019] 1. The utility model discloses a cantilevered perforating plate is arranged in the lower part of the rack, and the support roller and the drive roller are rotatably arranged on the both sides of the perforating plate, and the needle -punching mechanism and the pressing mechanism that can reciprocate up and down are arranged on the upper part of the rack, and the drive motor that drives the drive roller to rotate is arranged, so that the annular tire green tire blank can be supported through the cantilevered perforating plate and the support roller and the drive roller on both sides, and the needle -punching mechanism and the pressing mechanism that can reciprocate up and down are convenient for the replacement of the green tire blank, and the green tire blank can be driven to rotate automatically through the cooperation of the drive roller and the pressing mechanism, and the needle -punching mechanism that reciprocates up and down can punch holes on the green tire blank and exhaust, finally realize the automatic rotation and the hole -punching of the tire green tire blank, which not only is low in labor intensity, but also is uniform in hole -punching distribution and depth, and the vibration during work can be reduced through the alternate action of the pressing mechanism and the needle -punching mechanism, especially, the reciprocation up and down can be realized through the linear driving device, so that the vibration can be significantly reduced, the noise and the failure rate during work can be reduced, and the reliability of the device can be effectively improved.

[0020] 2. The needle -punching mechanism of the utility model is further composed of the needle -punching seat driven by the needle -punching linear driving device and the needle of the lower end of the needle -punching seat, and the needle -punching guide rod that penetrates the needle -punching guide sleeve is fixedly arranged on the both sides of the needle -punching seat, so that different needle -punching seats can be replaced according to the needs to meet the needle -punching exhaust needs of different diameters and densities, and the cooperation of the needle -punching guide sleeve and the needle -punching guide rod can ensure that the needle -punching seat reciprocates up and down, and the front and back are always parallel to the perforating plate, so that the problem that the depth of the holes before and after the perforating is not uniform can be prevented. And the needle -punching linear driving device of the hydraulic cylinder or the pneumatic cylinder structure can buffer the impact force acting on the needle when the needle -punching seat presses the hole, so that the wear and tear of the needle and the collision force of the steel wire in the green tire blank can be reduced, the degree of bending of the needle can be effectively reduced, and even the breaking can be avoided, and the effective contact time of the needle and the rubber in the green tire blank can be increased in the buffering process, so that the air inclusions in the green tire blank are fully released, and the vulcanization quality of the tire is further improved.

[0021] Therefore, the utility model has the characteristics of simple structure, safe and reliable, stab needle stability, low labor intensity. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structure schematic view of the utility model;

[0023] Figure 2 It is Figure 1 A-A direction sectional view of the utility model;

[0024] Figure 3 It is Figure 1 B-B direction sectional view of the utility model;

[0025] In the drawing: 1 - frame, 2 - puncture plate, 21 - let - go hole, 3 - support roller, 4 - drive roller, 5 - drive motor, 6 - needle - puncture mechanism, 61 - stab needle, 62 - stab needle seat, 621 - fixed seat, 622 - movable seat, 63 - needle - puncture linear drive device, 64 - needle - puncture guide rod, 65 - needle - puncture guide sleeve, 7 - compression mechanism, 71 - guide roller, 72 - compression linear drive device, 73 - compression support, 74 - compression guide rod, 75 - compression guide sleeve, 76 - guide frame, 77 - reset spring. DETAILED DESCRIPTION

[0026] In order to make the utility model's purpose, technical scheme and advantage more clearly, the following is combined with the drawing and example, and the utility model is further detailedly explained.It should be understood that the specific example described here is only used to explain the utility model, and is not used to limit the utility model.

[0027] As Figure 1 , 2 And 3, the utility model includes frame 1, puncture plate 2, support roller 3, drive roller 4, drive motor 5, needle - puncture mechanism 6, compression mechanism 7, the puncture plate 2 cantilevered horizontal fixed in the one side of frame 1 and the middle part is provided with let - go hole 21 along the length direction, the drive motor 5 is fixedly set up on frame 1, the support roller 3 and drive roller 4 are respectively parallelly set up in the both sides of puncture plate 2, the support roller 3 one end is rotatably connected with frame 1, the drive roller 4 one end is connected with the drive shaft of drive motor 5;

[0028] The needle - puncture mechanism 6 is set up on the frame 1 above puncture plate 2, the bottom of needle - puncture mechanism 6 is fixedly provided with several downwardly extending stab needle 61 along the length direction of puncture plate 2, the needle - puncture mechanism 6 can drive the stab needle 61 of bottom reciprocating movement and move into let - go hole 21;

[0029] The pressing mechanism 7 is arranged on the frame 1 above the driving roller 4, the bottom of the pressing mechanism 7 is rotatably provided with a guide roller 71 parallel to the driving roller 4, and the pressing mechanism 7 can drive the guide roller 71 at the bottom to reciprocate up and down to approach the driving roller 4.

[0030] The needling mechanism 6 further comprises a needle seat 62 and a needle straight-line driving device 63, the needle straight-line driving device 63 is vertically fixed on the frame 1, the needle seat 62 is arranged in parallel above the punching plate 2, the top of the needle seat 62 is connected with a driving rod of the needle straight-line driving device 63, and the lower end of the needle seat 62 is spaced apart in the length direction and provided with a plurality of downward extending needle 61.

[0031] The needle seat 62 further comprises a needle guide rod 64 and a needle guide sleeve 65, two needle guide sleeves 65 are respectively vertically fixed on the frame 1 on both sides of the needle straight-line driving device 63, and the needle guide rod 64 is respectively vertically fixed on both sides of the driving rod connection of the needle seat 62 in the length direction and respectively slid through the corresponding needle guide sleeve 65.

[0032] The needle seat 62 comprises a fixed seat 621 and a movable seat 622, the fixed seat 621 is an inverted "L" shaped long strip plate, the top end of the fixed seat 621 is connected with the driving rod of the needle straight-line driving device 63, the inner side of the fixed seat 621 is vertically provided with a plurality of grooves in the length direction and penetrating the lower end surface to accommodate the needle 61, and the movable seat 622 is detachably fixedly embedded in the inner side of the fixed seat 621 and the inner side of the movable seat 622 abuts against the needle 61 in the groove.

[0033] The upper surface of the punching plate 2 is a circular arc surface, and the top ends of the support roller 3 and the driving roller 4 are on the extension line of the circular arc surface of the punching plate 2.

[0034] The pressing mechanism 7 further comprises a pressing straight-line driving device 72 and a pressing support 73, the pressing straight-line driving device 72 is fixedly arranged on the frame 1, the pressing support 73 is arranged above the driving roller 4 and the top end of the pressing support 73 is connected with the driving rod of the pressing straight-line driving device 72, and the guide roller 71 is arranged at the lower end of the pressing support 73 and rotatably connected with the pressing support 73 at both ends.

[0035] The pressing support 73 is an "L" shaped support with an opening downward, and the guide roller 71 is embedded in the opening, and both ends of the guide roller 71 are rotatably connected with the inner side of the corresponding opening of the pressing support 73.

[0036] The pressing mechanism 7 further comprises a pressing guide rod 74 and a pressing guide sleeve 75, two pressing guide sleeves 75 are respectively fixedly arranged on the frame 1 on both sides of the pressing straight-line driving device 72, and the pressing guide rod 74 is respectively fixedly arranged on the pressing support 73 in the length direction close to both ends and respectively slid through the corresponding pressing guide sleeve 75.

[0037] The pressing mechanism 7 further comprises a guide frame 76, which is arranged between the pressing linear driving device 72 and the pressing support 73, is parallel to the pressing support 73, is fixedly connected with the rack 1 at one end, and is fixedly provided with the pressing guide sleeve 75.

[0038] The pressing guide sleeve 75 is fixedly arranged at one end of the guide frame 76 away from the pressing support 73, the pressing guide rod 74 is a T-shaped rod, and the pressing guide rod 74 is sleeved with a reset spring 77, the ends of which are respectively abutted with the end of the pressing guide rod 74 and the end face of the pressing guide sleeve 75.

[0039] The needle puncture linear driving device 63 and the pressing linear driving device 72 are air cylinders, hydraulic cylinders or linear motors.

[0040] The working principle of the utility model is as follows:

[0041] For example Figure 1 , 2As shown in Figure 3, during operation, the annular green tire blank is placed on the support roller 3, drive roller 4, and piercing plate 2. Then, the device is started, and the drive motor 5 fixed on the frame 1 drives the drive roller 4 to rotate. At the same time, the piston rod of the hydraulic cylinder or air cylinder (i.e., the needle linear drive device 63) of the needle piercing mechanism 6 on the frame 1 extends, pushing the needle seat 62 to drive the needle 61 on it to move downward and finally pierce or penetrate the rubber of the green tire blank to form a row of needle-type exhaust holes. At the same time, the impact force of the needle 61 on the green tire blank is transmitted to the hydraulic cylinder or air cylinder through the needle seat 62. The hydraulic oil or air inside is compressed and contracts, causing the piston rod, along with the needle 61 and the green tire blank on it, to move downward slightly to form a buffer. This not only buffers the impact force of the needle seat 62 pressing down to pierce the hole on the needle 61, but also increases the effective contact time between the needle 61 and the rubber in the green tire blank, achieving the purpose of effectively venting the air trapped in the green tire blank. After a row of needle-type vent holes is formed, as the piston rod of the hydraulic cylinder or pneumatic cylinder (i.e., the needle-piercing linear drive device 63) retracts, the needle seat 62 and the needles 61 on it move upward, detach from the green blank, and stop at a predetermined position. Subsequently, the piston rod of the hydraulic cylinder or pneumatic cylinder (i.e., the pressing linear drive device 72) of the clamping mechanism 7 on the frame 1 extends, pushing the clamping bracket 73 to drive the guide roller 71 on it to move downward and finally approach the drive roller 4 to clamp the green blank. Thus, the rotating drive roller 4 drives the green blank to rotate by a predetermined angle, thereby preventing the needles 61 from scratching the surface when the green blank rotates. This cycle of piercing and venting, and rotating angle, continues until the operator observes that the green blank has formed one full circle of needle-type vent holes, or the drive roller 4 has rotated a predetermined number of times to form one full circle of needle-type vent holes in the green blank. Then, the device is stopped, the green blank that has been pierced and vented is removed, and a new green blank is inserted. The above actions are repeated to complete the piercing and venting of a batch of green blanks.

[0042] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A highly reliable automatic puncture and venting device for tire blanks, characterized in that: The utility model relates to a needle punching machine, including frame (1), puncture plate (2), support roller (3), drive roller (4), drive motor (5), needle punching mechanism (6), press mechanism (7), puncture plate (2) cantilevered horizontal fixed in the one side of frame (1) and middle part is provided with the let -out hole (21) along the length direction, drive motor (5) fixed setting is in frame (1), support roller (3) and drive roller (4) are parallelly arranged respectively in the both sides of puncture plate (2), one end of support roller (3) is rotatably connected with frame (1), one end of drive roller (4) is connected with the drive shaft of drive motor (5), The needle punching mechanism (6) is arranged on the frame (1) above the puncture plate (2), and a plurality of downward extending needles (61) are fixedly arranged on the bottom of the needle punching mechanism (6) along the length direction of the puncture plate (2), the needle punching mechanism (6) can drive the needles (61) on the bottom to reciprocate up and down and penetrate into the let -out hole (21). The press mechanism (7) is arranged on the frame (1) above the drive roller (4), and a guide roller (71) parallel to the drive roller (4) is rotatably arranged on the bottom of the press mechanism (7), and the press mechanism (7) can drive the guide roller (71) on the bottom to reciprocate up and down and approach the drive roller (4).

2. The high-reliability automatic puncture and exhaust device for green tire according to claim 1, characterized in that: The needle punching mechanism (6) further comprises a needle seat (62) and a needle punching linear drive device (63), the needle punching linear drive device (63) is vertically fixed on the frame (1), the needle seat (62) is arranged above the puncture plate (2) in parallel, the top of the needle seat (62) is connected with a driving rod of the needle punching linear drive device (63), and a plurality of downward extending needles (61) are arranged at the lower end of the needle seat (62) along the length direction.

3. The high-reliability automatic puncture and exhaust device for green tire according to claim 2, characterized in that: The needle punching mechanism (6) further comprises a needle punching guide rod (64) and a needle punching guide sleeve (65), two needle punching guide sleeves (65) are vertically fixed on the frame (1) on the two sides of the needle punching linear drive device (63) respectively, and the needle punching guide rod (64) is vertically fixed on the driving rod connection position on the length direction of the needle seat (62) and slidably penetrates through the corresponding needle punching guide sleeve (65).

4. The high-reliability automatic puncture and exhaust device for green tire according to claim 2, characterized in that: The needle seat (62) comprises a fixed seat (621) and a movable seat (622), the fixed seat (621) is an inverted "L" shaped long strip plate, the top end of the fixed seat (621) is connected with the driving rod of the needle punching linear drive device (63), a plurality of grooves penetrating through the lower end surface to accommodate the needles (61) are vertically arranged on the inner side of the fixed seat (621) along the length direction, and the movable seat (622) is detachably embedded in the inner side of the fixed seat (621) and the inner side of the movable seat (622) abuts against the needles (61) in the grooves.

5. The high-reliability automatic puncture and exhaust device for green tire according to claim 1, characterized in that: The upper surface of the puncture plate (2) is a circular arc surface, and the top ends of the support roller (3) and the drive roller (4) are on the extension line of the circular arc surface of the puncture plate (2).

6. The high-reliability automatic puncture and degassing apparatus for a green tire according to any one of claims 1 to 5, characterized by: The pressing mechanism (7) further comprises a pressing linear driving device (72) and a pressing support (73), the pressing linear driving device (72) is fixedly arranged on the rack (1), the pressing support (73) is arranged above the driving roller (4) and the top end is connected with the driving rod of the pressing linear driving device (72), and the guide roller (71) is arranged at the lower end of the pressing support (73) and is rotatably connected with the pressing support (73) at both ends.

7. The high-reliability automatic puncture and exhaust device for green tire according to claim 6, characterized in that: The pressing support (73) is an "[” shaped support with an opening downward, and the guide roller (71) is embedded in the opening, and both ends of the guide roller (71) are rotatably connected with the inner side of the corresponding opening of the pressing support (73).

8. The high-reliability automatic puncture and exhaust device for green tire according to claim 7, characterized in that: The pressing mechanism (7) further comprises a pressing guide rod (74) and a pressing guide sleeve (75), two pressing guide sleeves (75) are fixedly arranged on the rack (1) on both sides of the pressing linear driving device (72), and the pressing guide rod (74) is fixedly arranged on the pressing support (73) near both ends in the length direction and respectively slidably penetrates through the corresponding pressing guide sleeve (75).

9. The high-reliability automatic puncture and exhaust device for green tire according to claim 8, characterized in that: The pressing mechanism (7) further comprises a guide frame (76), the guide frame (76) is arranged between the pressing linear driving device (72) and the pressing support (73), the guide frame (76) is parallel to the pressing support (73) and one end is fixedly connected with the rack (1), the pressing guide sleeve (75) is fixedly arranged on the guide frame (76), the guide frame (76) is provided with a through hole between the two pressing guide sleeves (75), the driving rod of the pressing linear driving device (72) movably penetrates through the through hole on the guide frame (76) and is fixedly connected with the pressing support (73).

10. The high-reliability automatic puncture and exhaust device for green tire according to claim 9, characterized in that: The pressing guide sleeve (75) is fixedly arranged at one end of the guide frame (76) away from the pressing support (73), the pressing guide rod (74) is a "T” shaped rod, and the pressing guide rod (74) is provided with two reset springs (77) sleeved thereon, and the ends of the reset springs (77) are respectively abutted with the end of the pressing guide rod (74) and the end surface of the pressing guide sleeve (75).

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