Punching device for automobile back door interior trimming panel

Abstract

The utility model provides an automobile back door interior trimming panel punching device, and relates to the field of automobile door interior trimming panel manufacturing. The positioning mold core comprises two first positioning blocks and a plurality of second positioning blocks; the pressing mechanism comprises two first pressing blocks and a plurality of second pressing blocks, wherein the first pressing blocks can ascend and descend and are located over the two first positioning blocks correspondingly. The edge cutting mechanism comprises two cutter assemblies located on the two sides of the front end of the positioning mold core correspondingly and an edge cutting driving cylinder used for driving the two cutter assemblies to move front and back correspondingly so as to achieve cutting of delta-shaped openings in the front sides of the two hinge holes. And the punching mechanism is used for punching and forming a through hole with a set shape in the rear end of the automobile inner plate. According to the automobile back door interior trimming panel punching device, through hole punching and hinge hole notching are integrated on one device, the two notching can be conducted synchronously, and the working efficiency is improved; mechanical equipment is used for automatically cutting, so that the cutting attractiveness is ensured and the product quality is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile interior trim panel manufacturing, and more specifically, to a punching device for an automobile rear door interior trim panel. Background Art

[0002] The automobile rear door interior trim panel is an important part of the whole vehicle interior trim, and plays an indispensable role in improving the competitiveness of the automobile. Its functions have also changed. It not only improves the interior decoration of the vehicle, but also requires the ceiling to have good heat insulation and heat insulation effects, as well as the functions of reducing vehicle interior noise and improving sound absorption effect.

[0003] As Figure 1 described, it is a relatively common rear door interior trim panel in the market. Based on the need for its installation structure with the vehicle body rear door, a through hole with a specific shape needs to be processed at the rear side position, and two hinge holes for the hinge shaft to pass through are provided on both sides of the front end thereof. In order to facilitate the installation of the hinge shaft, usually a cut is made at a position corresponding to the two hinge holes on the trim panel body. During installation, the cut is lifted to directly snap the hinge hole onto the hinge shaft. In the prior art, usually manual cutting tools are used to manually process the cut at the corresponding position on the interior trim panel, and then it is placed in a punching die for punching the through hole. This manual cutting method not only takes time and effort, but also the cut is prone to burrs, resulting in poor aesthetics and difficult to guarantee product quality; in addition, after the cut is completed, it has to be transferred to the punching die for punching, and the processing efficiency is low. Content of the Utility Model

[0004] To overcome at least one defect in the above prior art, the utility model provides a punching device for an automobile rear door interior trim panel, which integrates through hole punching and hinge hole cutting on one device, and can perform the two cuts synchronously, improving work efficiency; the mechanical device automatically cuts to ensure the aesthetics of the cut and improve product quality.

[0005] The utility model provides a punching device for an automobile rear door interior trim panel, including a frame, and a

[0006] positioning die core; including two first positioning blocks for respectively supporting the two positions corresponding to the two hinge holes on both sides of the front end of the automobile interior trim panel and a second positioning block for supporting the rear end of the automobile interior trim panel;

[0007] a pressing mechanism, including two first pressing blocks that can be lifted and are respectively located directly above the two first positioning blocks and several second pressing blocks for pressing on the upper surface of the rear end of the automobile interior trim panel;

[0008] a trimming mechanism, including two trimming knife assemblies respectively located on both sides of the front end of the positioning die core and a trimming driving cylinder for respectively driving the two trimming knife assemblies to move back and forth to cut out a "|" shaped opening in front of the two hinge holes;

[0009] The punching mechanism is located at the rear end of the positioning die insert and is used to punch a through hole with a set shape at the rear end of the inner panel of the vehicle.

[0010] Compared with the prior art, the punching device for the interior trim panel of the vehicle back door of the present utility model has the following advantages:

[0011] The punching device for the interior trim panel of the vehicle back door of the present utility model is a special equipment, which integrates the punching of the through hole of the interior trim panel and the machining of the hinge hole incision on one device, without the need for separate machining, omitting the intermediate transfer process and improving work efficiency; moreover, the machining position of the hinge hole incision of the interior trim panel is clamped and limited by a special pressing block and positioning block, so that the position of the interior trim panel is stable and immovable when the cutter assembly processes the incision, thus ensuring that the incision is clean and neat, and it is not easy to produce defects such as burrs and white edges around, improving the product quality; more importantly, the existing manual trimming is replaced by an automated device, which not only has high work efficiency, but also ensures that each incision is flat and beautiful.

[0012] As an improvement, a portal bracket is arranged on the top plate, a movable plate and a first driving cylinder for driving the vertical lifting of the movable plate are connected to the cross beam of the portal bracket, and the two first pressing blocks are respectively connected to the lower end surfaces of the left and right ends of the movable plate. In the above improved structure, the lifting drive of the two first pressing blocks is realized through structures such as the portal bracket and the movable plate, and the structure is simple and the drive is convenient.

[0013] As a further improvement, a third pressing block is connected to the middle of the lower end surface of the movable plate, and a third positioning block located below the third pressing block is also arranged on the top plate. In the above improved structure, the third pressing block and the third positioning block make the pressing and limiting of the interior trim panel more stable, and it is not easy to displace during the punching and trimming processes, ensuring the accuracy of the incision and punching positions.

[0014] As a further improvement, the left and right ends of the movable plate are respectively connected to the two vertical columns of the portal bracket through two linear guide rails; and vertical guide rods are respectively connected to the two ends of the movable plate, and two guide sleeves for the two guide rods to slide and cooperate are connected to the cross beam. In the above improved structure, the guide rod and guide sleeve structure further improves the smoothness of the lifting of the movable plate.

[0015] Furthermore, the cutter assembly includes a blade and two blade fixing rods arranged at intervals up and down and parallel to each other. The upper and lower ends of the blade are respectively connected to the left ends of the two blade fixing rods, and the right ends of the two blade fixing rods are both connected to the driving end of the trimming driving cylinder.

[0016] Further improved, the rear end of the upper blade fixing rod among the two blade fixing rods protrudes beyond the rear end of the lower blade fixing rod, so that the blades are arranged in an inclined shape; guiding grooves for the two blade fixing rods to slide horizontally are respectively formed in the first pressing block and the first positioning block, and an avoidance groove for the blades to pass through is formed between the two guiding grooves. In the above improved structure, the guiding grooves are arranged to make the cutting movement of the two blade fixing rods driving the blades from front to back more stable, ensuring that the cut is flat and beautiful.

[0017] Further improved, connecting seats are connected to the driving ends of the two trimming driving cylinders, the connecting seats are connected to the top plate through linear guide rails, and the right ends of the two blade fixing rods are connected to the connecting seats. In the above improved structure, the two blade fixing rods are connected to the trimming driving cylinders through the connecting seats, ensuring the stability of the connection structure.

[0018] Furthermore, the punching mechanism includes a cutter head, a punching driving cylinder and a support seat. The support seat is connected to the top plate, the punching driving cylinder is vertically connected to the support seat, and the cutter head is slidably matched with the support seat through a linear guide rail and its upper end is connected to the driving end of the trimming driving cylinder.

[0019] Further improved, a positioning seat is connected to the slider of the linear guide rail, the upper end of the positioning seat is connected to the driving end of the punching driving cylinder, and the upper end of the cutter head is connected to the positioning seat; a vertically telescopic buffer cushion block is further connected to the lower end of the positioning seat, and a communication hole is formed in the buffer cushion block. When the punching driving cylinder drives the positioning seat to descend until the buffer cushion block abuts against the automotive interior trim panel, the positioning seat continues to descend so that the lower end of the cutter head passes through the communication hole to punch the automotive interior trim panel.

[0020] Further improved, two countersunk through holes are formed in the upper end of the positioning seat, two connecting bolts for connecting to the buffer cushion block are movably inserted into the two countersunk through holes, and springs are sleeved on the outer parts of the two connecting bolts, and the upper and lower ends of the springs respectively abut against the positioning seat and the buffer cushion block.

[0021] Other improved features and advantages of the present invention will be described in the subsequent specific embodiments, and some of them will become obvious from the description or can be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the description and the drawings. Description of the Drawings

[0022] Figure 1 It is a structural diagram of an automotive interior trim panel in the prior art;

[0023] Figure 2This is a three-dimensional structure diagram of the working state of the punching device for the automobile back door interior trim panel of the present utility model;

[0024] Figure 3 This is another three-dimensional structure diagram of the working state of the punching device for the automobile back door interior trim panel of the present utility model;

[0025] Figure 4 This is a three-dimensional structure diagram of the non-working state of the punching device for the automobile back door interior trim panel of the present utility model;

[0026] Figure 5 This is another three-dimensional structure diagram of the non-working state of the punching device for the automobile back door interior trim panel of the present utility model;

[0027] Figure 6 This is a partial cross-sectional view of the punching device for the automobile back door interior trim panel of the present utility model;

[0028] Figure 7 This is a partial enlarged view of the punching device for the automobile back door interior trim panel of the present utility model.

[0029] Explanation of reference numerals:

[0030] 1, frame; 2, first positioning block; 3, second positioning block; 4, first pressing block; 5, second pressing block; 6, edge-cutting driving cylinder; 7, portal bracket; 8, movable plate; 9, first driving cylinder; 10, third pressing block; 11, third positioning block; 12, guide rod; 13, guide sleeve; 14, blade; 15, blade fixing rod; 16, guide groove; 17, avoidance groove; 18, connecting seat; 19, tool bit; 20, punching driving cylinder; 21, support seat; 22, positioning seat; 23, buffer cushion block; 24, countersunk through hole; 25, connecting bolt; 26, spring; 27, automobile interior trim panel; 28, hinge hole; 29, "|" type opening; 30, punching hole; 31, lifting and rotating driving cylinder; 32, positioning convex column. Detailed implementation manners

[0031] First of all, those skilled in the art should understand that these implementation manners are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments according to needs to adapt to specific application scenarios.

[0032] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "fixed" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations.

[0033] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by terms such as "upper end", "lower end", "front and back", "left and right", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.

[0034] The following further details the present application in conjunction with the drawings and specific embodiments.

[0035] See Figures 2 to 7 As shown, the embodiment of the present application discloses a punching device for an automobile back door interior trim panel, including a frame 1. Specifically, the frame 1 includes a rectangular workbench. On the top plate of the workbench, there are provided a positioning die core for placing the automobile interior trim panel 27, a pressing mechanism for pressing and limiting the automobile interior trim panel 27 on the positioning die core, a trimming mechanism for trimming the two hinge holes 28 on both sides of the front end of the automobile interior trim panel 27, and a punching mechanism 30 for punching holes 30 at the rear end of the automobile inner panel. That is, a single tooling can achieve trimming at the positions of the two hinge holes 28 of the automobile interior trim panel 27 and through-hole punching, with high automation and processing efficiency.

[0036] Specifically, the positioning die core in this embodiment includes two first positioning blocks 2 for respectively supporting the corresponding positions on both sides of the front end of the automobile interior trim panel 27 corresponding to the two hinge holes 28, and a second positioning block 3 for supporting the rear end of the automobile interior trim panel 27. The pressing mechanism includes two first pressing blocks 4 that can be lifted and lowered and are respectively located directly above the two first positioning blocks 2, and several second pressing blocks 5 for pressing on the upper surface of the rear end of the automobile interior trim panel 27. And in this structure, a plurality of positioning convex columns 32 are also provided on the second positioning block 3. When positioning the automobile interior trim panel 27, it is horizontally placed on the positioning die core along the set direction, ensuring that the positions on both sides of the front end of the automobile interior trim panel 27 that need to be trimmed are pressed and limited between the first positioning block 2 and the first pressing block 4, and the preformed through-holes at the rear end of the automobile interior trim panel 27 are matched with the corresponding positioning convex columns 32. Lifting and rotating drive cylinders 31 are respectively arranged on both sides at the rear end of the positioning die core, and each second pressing block 5 is connected to the driving arm of each lifting and rotating drive cylinder 31 for pressing and limiting both sides of the rear end of the automobile interior trim panel 27.

[0037] In addition, the trimming mechanism includes two trimming knife assemblies respectively located on both sides of the front end of the positioning die core, and a trimming drive cylinder 6 for respectively driving the two trimming knife assemblies to move back and forth to cut out a "|" - shaped opening 29 in front of the two hinge holes 28.

[0038] More specifically, see the attached Figure 6, in this embodiment, the cutting tool assembly includes a blade 14 and two blade fixing rods 14 that are arranged at intervals up and down and are parallel to each other. The upper and lower ends of the blade 14 are respectively connected to the left ends of the two blade fixing rods 14. The right ends of the two blade fixing rods 14 are both connected to the driving end of the trimming driving cylinder 6. By driving the trimming driving cylinder 6, the two blade fixing rods 14 are driven to move horizontally, so as to drive the blade 14 to move horizontally from front to back, realizing vertical cutting of the hinge hole 28 position at the front end of the automotive interior panel 27, that is, cutting a "|" - shaped opening that penetrates through to the hinge hole 28 on the front - side body of the automotive interior panel 27.

[0039] Preferably, the lengths of the two blade fixing rods 14 are not equal. Specifically, it means that the rear end of the upper blade fixing rod 14 protrudes from the rear end of the lower blade fixing rod 14, so that the blade 14 is arranged in an inclined shape. In addition, guide grooves 16 for the two blade fixing rods 14 to slide horizontally are respectively formed on the first pressing block 4 and the first positioning block 2, and an avoidance groove 17 for the blade 14 to pass through is formed between the two guide grooves 16. The arrangement of the guide grooves 16 makes the cutting movement of the two blade fixing rods 14 driving the blade 14 from front to back more stable. In addition, since the trimming position is pre - pressed and limited between the first pressing block 4 and the first positioning block 2, it better ensures that the cut is flat and there is no curling, improving the product quality; moreover, the trimming of the two hinge hole 28 positions on both sides of the automotive interior panel 27 is carried out simultaneously, with high efficiency.

[0040] In this embodiment, in order to further improve the stability during trimming, connection seats 18 are connected to the driving ends of the two trimming driving cylinders 6. The two connection seats 18 are respectively connected to the two sides at the front end of the top plate through linear guide rails, and correspond to the two hinge hole 28 positions on the automotive interior panel 27, and the right ends of the two blade fixing rods 14 are both connected to the connection seats 18.

[0041] See the attached drawings, see the atta Figure 2 , in this embodiment, a portal - shaped bracket 7 is arranged on the top plate, and the portal - shaped bracket 7 is arranged across in the left - right direction of the frame 1. A vertically extending first driving cylinder 9 is connected to the cross - beam of the portal - shaped bracket 7, and a movable plate 8 is connected to the piston rod at the lower end of the first driving cylinder 9. The two first pressing blocks 4 are respectively connected to the lower surfaces at the left and right ends of the movable plate 8. Specifically, the left and right ends of the movable plate 8 are respectively connected to the two vertical columns of the portal - shaped bracket 7 through two linear guide rails; and vertically arranged guide rods 12 are respectively connected to both ends of the movable plate 8, and guide sleeves 13 for the two guide rods 12 to slide and cooperate are connected to the cross - beam, thus effectively ensuring the smoothness of the lifting of the movable plate 8.

[0042] In addition, see the atta Figure 4, To ensure the stability of the press-fitting of the automotive interior trim panel 27, in the above structure, a third pressing block 10 is further connected to the middle of the lower end surface of the movable plate 8. Correspondingly, a third positioning block 11 is provided on the top plate directly below the third pressing block 10. The third pressing block 10 and the third positioning block 11 are used to further press and limit the middle position of the front end of the automotive interior trim panel 27.

[0043] Continue to refer to the appendix Figure 5 , 7 , In this embodiment, the punching 30 mechanism includes a cutter head 19, a punching 30 driving cylinder 20, and a support seat 21. The support seat 21 is connected to the top plate. The punching 30 driving cylinder 20 is vertically connected to the support seat 21. The cutter head 19 is slidably fitted on the support seat 21 through a linear guide rail, and its upper end is connected to the driving end of the trimming driving cylinder 6.

[0044] In the above structure, specifically, a positioning seat 22 is connected to the slider of the linear guide rail. The upper end of the positioning seat 22 is connected to the driving end of the punching 30 driving cylinder 20. The upper end of the cutter head 19 is connected to the positioning seat 22. A vertically telescopic buffer pad 23 is further connected to the lower end of the positioning seat 22. A communication hole is provided in the buffer pad 23. When the punching 30 driving cylinder 20 drives the positioning seat 22 to descend until the buffer pad 23 abuts against the automotive interior trim panel 27, the positioning seat 22 continues to descend so that the lower end of the cutter head 19 can pass through the communication hole to punch 30 at the corresponding position on the automotive interior trim panel 27.

[0045] In this embodiment, refer to the appendix Figure 7 , The fact that the buffer pad 23 is vertically telescopic means that two counterbore through holes 24 are provided in the upper end of the positioning seat 22. Two connecting bolts 25 for connecting to the buffer pad 23 are movably inserted into the two counterbore through holes 24, and springs 26 are sleeved on the outer parts of the two connecting bolts 25. The upper and lower ends of the springs 26 are respectively abutted against the positioning seat 22 and the buffer pad 23. In the initial state, under the elastic force of the spring 26, the buffer pad 23 moves downward to the limit position, and at this time, the lower end surface of the buffer pad 23 extends beyond the lower end surface of the cutter head 19. That is, during the punching 30 process, the positioning seat 22 drives the cutter head 19 and the buffer pad 23 to descend synchronously until the lower end surface of the buffer pad 23 abuts against the automotive interior trim panel 27 in advance, and the buffer pad 23 no longer moves. The positioning seat continues to descend and drives the cutter head 19 to descend through the communication hole to punch 30 on the automotive interior trim panel 27. And during the punching 30 process, since the elastic force of the spring 26 needs to be overcome for slow punching, the cutter head 19 can be protected. The buffer pad 23 in this structure is both used to pre-press the automotive interior trim panel 27 to improve the stability during punching 30 and can play a role in punching buffer.

[0046] In the foregoing description, the first driving cylinder 9 is preferably a hydraulic cylinder, and the remaining driving cylinders are preferably air cylinders. The air cylinders use compressed air as the air source, which is cleaner and more environmentally friendly; the first driving cylinder 9 is selected as a hydraulic cylinder to ensure the stability when the automotive interior trim panel 27 is pressed and limited. The stability of the hydraulic cylinder is stronger than that of the air cylinder.

[0047] In addition, corresponding operation buttons are provided on the top plate at the front end of the frame 1, which facilitates one-key start and stop operations for workers.

[0048] In the description of the present application, the descriptions referring to the terms "this embodiment", "some embodiments" mean that the specific features, mechanisms, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0049] As described above, it is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A punching device for a car back door interior panel, characterized in that: It comprises a frame (1), on the top plate of which is provided a The positioning mold core comprises two first positioning blocks (2) for respectively supporting the positions of the two sides of the front end of the automobile interior panel (27) corresponding to the two hinge holes (28) and a second positioning block (3) for supporting the rear end of the automobile interior panel (27); The pressing mechanism comprises two first pressing blocks (4) which can be raised and lowered and are respectively located directly above the two first positioning blocks (2) and a plurality of second pressing blocks (5) for pressing against the upper surface of the rear end of the automobile interior trim panel (27); The trimming mechanism comprises two cutting knife assemblies respectively located at two sides of the front end of the positioning mold core and a trimming drive cylinder (6) for respectively driving the two cutting knife assemblies to move forward and backward to cut out a "∣"-shaped opening (29) at the front side of the two hinge holes (28); A punching mechanism (30) is located at the rear end of the positioning die core and is used for punching and forming a through hole of a set shape at the rear end of the automobile interior trim panel (27).

2. The automobile back door interior panel punching device according to claim 1, characterized in that: A door-shaped bracket (7) is arranged on the top plate, a movable plate (8) and a first driving cylinder (9) for driving the movable plate (8) to vertically lift are connected to the cross beam of the door-shaped bracket (7), and two first pressing blocks (4) are respectively connected to the lower end surfaces of the left and right ends of the movable plate (8).

3. The automobile back door interior trim punching device according to claim 2, characterized in that: A third pressing block (10) is connected to the middle of the lower end surface of the movable plate (8), and a third positioning block (11) located below the third pressing block (10) is also provided on the top plate.

4. The automobile back door interior trim punching device according to claim 2, characterized in that: The left and right ends of the movable plate (8) are respectively connected to the two vertical columns of the door-shaped bracket (7) through two linear guide rails; and the two ends of the movable plate (8) are also respectively connected to vertically arranged guide rods (12), and the crossbeam is connected to another guide sleeve (13) for slidingly matching the two guide rods (12).

5. The automobile back door interior trim punching device according to any one of claims 1 to 4, characterized in that: The cutter assembly comprises a blade (14) and two blade (14) fixing rods which are spaced apart and parallel to each other. The upper and lower ends of the blade (14) are respectively connected to the left ends of the two blade (14) fixing rods, and the right ends of the two blade (14) fixing rods are connected to the driving end of the trimming driving cylinder (6).

6. The automobile back door interior trim punching device according to claim 5, characterized in that: The rear end of the upper blade (14) fixing rod of the two blade (14) fixing rods protrudes from the rear end of the lower blade (14) fixing rod, so that the blade (14) is arranged in an inclined shape; the first pressing block (4) and the first positioning block (2) are respectively provided with guide grooves (16) for the two blade (14) fixing rods to slide horizontally, and an avoidance groove (17) for the blade (14) to pass through is provided between the two guide grooves (16).

7. The automobile back door interior trim punching device according to claim 5, characterized in that: The driving ends of the two trimming drive cylinders (6) are connected to a connecting seat (18), the connecting seat (18) is connected to the top plate via a linear guide rail, and the right ends of the two blade (14) fixing rods are connected to the connecting seat (18).

8. The automobile back door interior trim punching device according to any one of claims 1 to 4, characterized in that: The punching (30) mechanism comprises a cutter head (19), a punching (30) driving cylinder (20) and a support seat (21); the support seat (21) is connected to the top plate; the punching (30) driving cylinder (20) is vertically connected to the support seat (21); the cutter head (19) is slidably engaged on the support seat (21) via a linear guide rail and its upper end is connected to the driving end of the trimming driving cylinder (6).

9. The automobile back door interior trim punching device according to claim 8, characterized in that: A positioning seat (22) is connected to the slider of the linear guide rail, the upper end of the positioning seat (22) is connected to the driving end of the punching (30) driving cylinder (20), and the upper end of the cutter head (19) is connected to the positioning seat (22); the lower end of the positioning seat (22) is also connected to a buffer pad (23) which is retractable in the vertical direction, and a connecting hole is provided on the buffer pad (23). When the punching (30) driving cylinder (20) drives the positioning seat (22) downward until the buffer pad (23) abuts against the automobile interior panel (27), the positioning seat (22) continues to move downward so that the lower end of the cutter head (19) passes through the connecting hole to achieve punching (30) of the automobile interior panel (27).

10. The automobile back door interior trim punching device according to claim 9, characterized in that: Two countersunk through holes (24) are formed at the upper end of the positioning seat (22), and two connecting bolts (25) for connecting to the buffer block (23) are movably inserted in the two countersunk through holes (24), and springs (26) are sleeved on the outside of the two connecting bolts (25), and the upper and lower ends of the springs (26) are respectively in contact with the positioning seat (22) and the buffer block (23).

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