Positioning clamp for diesel engine piston machining

Abstract

The invention relates to the technical field of diesel engine piston machining, in particular to a diesel engine piston machining positioning clamp which comprises a bottom plate, a supporting frame is arranged above the bottom plate and connected with the bottom plate through a rotating mechanism, and at least one set of positioning mechanisms is arranged outside the supporting frame. A sleeve slidably penetrates through the interior of the supporting frame, a stand column is slidably installed in the sleeve and penetrates through the lower portion of the sleeve, the sleeve is rotationally connected with the supporting frame through a rotating device, and two sets of positioning pieces are installed in the sleeve through an elastic device. According to the positioning clamp for machining the piston of the diesel engine, the two sets of positioning pieces are arranged, under the cooperation of the stand column and the sleeve, the stand column drives the positioning pieces to move upwards in the piston, at the moment, the piston can rotate, the two sets of positioning pieces can penetrate through a piston pin hole, and the position of the piston pin hole can be rapidly positioned.

Description

Technical Field

[0001] The present invention relates to the technical field of diesel engine piston processing, and particularly to a positioning fixture for diesel engine piston processing. Background Technique

[0002] As an important component in an internal combustion engine, most pistons on the market are forgings at present. For forged pistons, their surfaces need to be further processed. Therefore, during the piston processing, accurate positioning tooling fixtures are crucial for ensuring processing accuracy and improving production efficiency. Conventional piston processing positioning fixtures often have some limitations. For example, they are applicable to a single piston specification and are difficult to meet diverse production requirements.

[0003] When the existing fixtures clamp the piston, they generally clamp the piston from the outside or inside. During processing, the piston is prone to shaking. Moreover, when the fixture clamps the piston, it cannot position the piston pin hole, which easily affects the processing effect of the piston ring. Summary of the Invention

[0004] The purpose of the present invention is to provide a positioning fixture for diesel engine piston processing to solve the problems raised in the above background technique.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A positioning fixture for diesel engine piston processing, including a bottom plate. Above the bottom plate, there is a support frame. The support frame is connected to the bottom plate through a rotating mechanism. The outside of the support frame is provided with a positioning mechanism. The number of the positioning mechanisms is at least one group. The positioning mechanism includes a support plate. The support plate is arranged above the support frame. On the side of the support plate away from the support frame, two groups of clamping plates are slidably installed. The clamping plates are connected to the support frame through a pushing device. A sleeve is slidably penetrated through the inside of the support frame. Inside the sleeve, a column is slidably installed. The column penetrates below the sleeve. The sleeve is rotationally connected to the support frame through a rotating device. Inside the sleeve, two groups of positioning members are installed through an elastic device.

[0006] Preferably, the rotating mechanism includes a rotating mechanism. The rotating mechanism includes a vertical plate. The vertical plate is fixedly installed above the bottom plate. On the side of the vertical plate away from the support frame, a motor is fixedly installed. The output end of the motor is fixedly installed with a rotating member. The rotating member communicates with the support frame. At the end of the rotating member away from the support frame, a blower is fixedly installed. An air outlet is opened on the outside of the support frame. The air outlet communicates with the column.

[0007] Preferably, a fixing rod is fixedly installed inside the support frame. A baffle is slidably sleeved on the outer surface of the fixing rod. The area of the baffle is larger than the area of the air outlet. A fourth spring is movably sleeved on the outer surface of the fixing rod, and the fourth spring is fixedly connected to the baffle.

[0008] Preferably, the pushing device includes push plates. The number of push plates is two groups. The two groups of push plates are respectively located on the opposite sides of the two groups of clamping plates. A rod member is slidably penetrated inside the push plate. The rod member is fixedly connected to the clamping plate. A first spring is movably sleeved on the outer surface of the rod member. The first spring is located between the clamping plate and the push plate. The push plate is connected to the support plate through a sliding assembly.

[0009] Preferably, the sliding assembly includes a chute. The chute is opened inside the support plate. A slider is slidably installed inside the chute. The slider is fixedly connected to the clamping plate. An elastic member is fixedly installed inside the chute. The elastic member is connected to the slider. A connecting plate is rotatably installed below the slider. One end of the connecting plate away from the slider is fixedly connected to the surface of the support frame. The connecting plate is inclined.

[0010] Preferably, the rotating device includes a toothed ring and a rack. The toothed ring is fixedly sleeved on the outside of the column. The toothed ring is rotatably connected to the support frame. The rack is slidably installed above the support frame. The rack is engaged with the toothed ring. The rack is connected to the support plate through a pushing assembly.

[0011] Preferably, the pushing assembly includes a pressing plate. The pressing plate is connected to the support frame through a lifting structure. The pressing plate is located between the support plate and the rack. An installation block is fixedly installed above the rack. A pushing block is rotatably installed above the installation block. One end of the pushing block away from the installation block is rotatably connected to the pressing plate.

[0012] Preferably, the lifting structure includes a support rod. The support rod is fixedly installed on the outer surface of the support frame. The support rod is slidably connected to the pressing plate. A third spring is movably sleeved on the outer surface of the support rod. The third spring is fixedly connected to the pressing plate.

[0013] Preferably, the elastic device includes a groove. The groove is opened inside the column. A second spring is movably installed inside the groove. The second spring is fixedly connected to the positioning member. The positioning member is slidably connected to the groove.

[0014] Preferably, the elastic device further includes a guide groove and a guide block. The guide groove is opened on the outside of the sleeve. The guide block is fixedly connected to the outer surface of the column. The guide block is slidably connected to the guide groove. The guide groove is inserted and matched with the positioning member. A second magnet is fixedly installed above the column. A first magnet is fixedly installed inside the sleeve. The first magnet and the second magnet repel each other.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. By providing two sets of positioning members, with the cooperation of the column and the sleeve, the column drives the positioning members to move upward inside the piston. At this time, the piston can rotate, enabling the two sets of positioning members to penetrate the piston pin hole to fix the piston, which is beneficial to increasing the stability of the piston and can quickly position the position of the piston pin hole, making the processing of the piston ring more accurate.

[0016] 2. By providing a rotatable support frame, four sets of positioning mechanisms are provided in this embodiment, enabling the four pistons to be fixed outside the support frame for different processes, which is beneficial to improving the efficiency of piston processing.

[0017] 3. By providing an air outlet, with the cooperation of the baffle, the fan conveys air through the rotating member into the interior of the support frame and outputs it through the air outlet, enabling the air to be conveyed into the piston, which is beneficial to cooling the piston from the inside and making the processing effect of the piston better. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a sectional view of the structure of the present invention; Figure 3 is a sectional view of the structure of the present invention from another perspective; Figure 4 is a schematic diagram of the partial structure of the present invention; Figure 5 is of the present invention Figure 4 sectional view of the structure; Figure 6 is a partial sectional view of the structure of the present invention; Figure 7 is of the present invention Figure 6 enlarged view of part A; Figure 8 is a partial sectional view of the structure of the present invention.

[0019] In the attached drawings, the list of components represented by each reference numeral is as follows: 1. bottom plate; 2. support frame; 3. support plate; 4. clamping plate; 5. push plate; 6. rod; 7. first spring; 8. chute; 9. slider; 10. elastic member; 11. connecting plate; 12. column; 13. sleeve; 14. first magnet; 15. second magnet; 16. guide groove; 17. guide block; 18. groove; 19. positioning member; 20. second spring; 21. toothed ring; 22. rack; 23. mounting block; 24. pressing plate; 25. push block; 26. support rod; 27. third spring; 28. vertical plate; 29. rotating member; 30. motor; 31. blower; 32. air outlet; 33. baffle; 34. fixed rod; 35. fourth spring. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] Please refer to Figures 1 - 8 , a positioning fixture for diesel engine piston machining shown in the figure, includes a bottom plate 1. Above the bottom plate 1, there is a support frame 2. The support frame 2 is connected to the bottom plate 1 through a rotating mechanism. An indexing mechanism is arranged outside the support frame 2. The number of the indexing mechanisms is at least one group. The indexing mechanism includes a support plate 3. The support plate 3 is arranged above the support frame 2. Two groups of clamping plates 4 are slidably installed on one side of the support plate 3 away from the support frame 2. The clamping plates 4 are connected to the support frame 2 through a pushing device. A sleeve 13 is slidably penetrated through the inside of the support frame 2. A column 12 is slidably installed inside the sleeve 13. The column 12 penetrates below the sleeve 13. The sleeve 13 is rotatably connected to the support frame 2 through a rotating device. Two groups of positioning members 19 are installed inside the sleeve 13 through an elastic device.

[0022] The rotating mechanism includes a rotating mechanism. The rotating mechanism includes a vertical plate 28. The vertical plate 28 is fixedly installed above the bottom plate 1. A motor 30 is fixedly installed on one side of the vertical plate 28 away from the support frame 2. The output end of the motor 30 is fixedly installed with a rotating member 29. The rotating member 29 communicates with the support frame 2. A blower 31 is fixedly installed at one end of the rotating member 29 away from the support frame 2. An air outlet 32 is opened outside the support frame 2. The air outlet 32 communicates with the column 12.

[0023] Specifically, with the cooperation of the bottom plate 1 and the vertical plate 28, the motor 30 is connected to an external power supply. The motor 30 drives the support frame 2 to rotate through the rotating member 29. When the support frame 2 rotates, it can drive the piston positioned above the support frame 2 to rotate synchronously. After the piston rotates 90 degrees, it pauses, so that the piston can be processed. In this embodiment, four groups of positioning mechanisms are provided, which is beneficial to improving the processing efficiency of the piston. The blower 31 conveys the external air to the inside of the support frame 2 through the rotating member 29 and discharges it through the air outlet 32. The air is conveyed into the piston, which is convenient for cooling the piston from the inside.

[0024] A fixing rod 34 is fixedly installed inside the support frame 2. A baffle 33 is slidably sleeved on the outer surface of the fixing rod 34. The area of the baffle 33 is larger than the area of the air outlet 32. A fourth spring 35 is movably sleeved on the outer surface of the fixing rod 34. The fourth spring 35 is fixedly connected to the baffle 33.

[0025] Specifically, when the piston is located above the support frame 2, under the action of gravity, the baffle 33 moves downward on the outside of the fixing rod 34, and the baffle 33 is separated from the inner wall of the support frame 2, so that the air inside the support frame 2 can pass through the air outlet 32. At this time, the fourth spring 35 is deformed by force. When the piston rotates to the side and bottom of the support frame 2, under the elastic force of the fourth spring 35, the fourth spring 35 pushes the baffle 33 to contact the inner wall of the support frame 2, and the baffle 33 blocks the air outlet 32, so that the air inside the support frame 2 can only be conveyed from the upper air outlet 32, which is beneficial to improving the heat dissipation effect.

[0026] The pushing device includes a push plate 5. The number of push plates 5 is two groups. The two groups of push plates 5 are respectively located on the sides away from each other of the two groups of clamping plates 4. A rod member 6 is slidably penetrated inside the push plate 5. The rod member 6 is fixedly connected to the clamping plate 4. A first spring 7 is movably sleeved on the outer surface of the rod member 6. The first spring 7 is located between the clamping plate 4 and the push plate 5. The push plate 5 is connected to the support plate 3 through a sliding assembly.

[0027] The sliding assembly includes a chute 8. The chute 8 is opened inside the support plate 3. A slider 9 is slidably installed inside the chute 8. The slider 9 is fixedly connected to the clamping plate 4. An elastic member 10 is fixedly installed inside the chute 8. The elastic member 10 is connected to the slider 9. A connecting plate 11 is rotatably installed below the slider 9. One end of the connecting plate 11 away from the slider 9 is fixedly connected to the surface of the support frame 2. The connecting plate 11 is inclined.

[0028] Specifically, place the piston on the side of the support plate 3 away from the support frame 2. The piston drives the support plate 3 to move towards the support frame 2. At this time, the connecting plate 11 rotates. The connecting plate 11 drives the push plate 5 to slide inside the chute 8 through the slider 9. At this time, the elastic member 10 is deformed under force. When the two push plates 5 approach each other, they drive the two clamping plates 4 to move synchronously. The two clamping plates 4 can clamp the piston from the side. The piston continues to move. At this time, the clamping plate 4 stops moving, and the push plate 5 moves towards the clamping plate 4 on the outer surface of the rod member 6, and the first spring 7 is compressed under force, so as to clamp the piston, which is beneficial to increasing the stability of the piston during processing.

[0029] The rotating device includes a toothed ring 21 and a rack 22. The toothed ring 21 is fixedly sleeved outside the column 12. The toothed ring 21 is rotatably connected to the support frame 2. The rack 22 is slidably installed above the support frame 2. The rack 22 meshes with the toothed ring 21. The rack 22 is connected through a pushing component including a support plate 3.

[0030] The pushing component includes a pressing plate 24. The pressing plate 24 is connected to the support frame 2 through a lifting structure. The pressing plate 24 is located between the support plate 3 and the rack 22. An installation block 23 is fixedly installed above the rack 22. A push block 25 is rotatably installed above the installation block 23. One end of the push block 25 away from the installation block 23 is rotatably connected to the pressing plate 24.

[0031] The lifting structure includes a support rod 26. The support rod 26 is fixedly installed on the outer surface of the support frame 2. The support rod 26 is slidably connected to the pressing plate 24. A third spring 27 is movably sleeved on the outer surface of the support rod 26. The third spring 27 is fixedly connected to the pressing plate 24.

[0032] Specifically, when the support plate 3 moves downward, it contacts the pressing plate 24 and drives the pressing plate 24 to move synchronously. At this time, the support rod 26 penetrates the chute 8. The pressing plate 24 drives the push block 25 to rotate. The push block 25 drives the rack 22 to move synchronously through the installation block 23. Since the rack 22 meshes with the toothed ring 21, the rack 22 can drive the column 12 to rotate through the toothed ring 21. At this time, the third spring 27 is compressed under force.

[0033] The elastic device includes a groove 18. The groove 18 is opened inside the column 12. A second spring 20 is movably installed inside the groove 18. The second spring 20 is fixedly connected to the positioning member 19. The positioning member 19 is slidably connected to the groove 18.

[0034] The elastic device further includes a guide groove 16 and a guide block 17. The guide groove 16 is formed on the outer part of the sleeve 13. The guide block 17 is fixedly connected to the outer surface of the column 12. The guide block 17 is slidably connected to the guide groove 16. The guide groove 16 and the positioning member 19 are inserted and matched. Above the column 12, a second magnet 15 is fixedly installed. Inside the sleeve 13, a first magnet 14 is fixedly installed. The first magnet 14 and the second magnet 15 repel each other.

[0035] When the piston moves to the outside of the sleeve 13 and the upper part of the sleeve 13 contacts the inner wall of the piston, the piston drives the sleeve 13 to move synchronously. In the initial state, under the action of the first magnet 14 and the second magnet 15, since the first magnet 14 and the second magnet 15 repel each other, the sleeve 13 moves away from the column 12. When the piston drives the sleeve 13 to move, at this time, the guide block 17 slides inside the guide groove 16. In the initial state, the positioning member 19 is located inside the groove 18. When the positioning member 19 moves to the position of the guide groove 16, the second spring 20 pushes the positioning member 19 out of the inside of the groove 18. At this time, the positioning member 19 penetrates the guide groove 16 and contacts the inner wall of the piston. When the positioning member 19 moves to the position of the piston pin hole, the second spring 20 pushes the positioning member 19 through the piston pin hole, which is beneficial to increasing the stability when the piston is fixed and can quickly position the piston pin hole, making the processing of the piston more precise.

[0036] Working principle: With the cooperation of the bottom plate 1 and the vertical plate 28, the motor 30 is connected to an external power supply. The motor 30 drives the support frame 2 to rotate through the rotating member 29. When the support frame 2 rotates, it can drive the piston positioned above the support frame 2 to rotate synchronously. After the piston rotates 90 degrees, it pauses.

[0037] Place the piston on the side of the support plate 3 away from the support frame 2. The piston drives the support plate 3 to move towards the support frame 2. At this time, the connecting plate 11 rotates. The connecting plate 11 drives the push plate 5 to slide inside the chute 8 through the slider 9. At this time, the elastic member 10 deforms under force. When the two push plates 5 approach each other, they drive the two clamping plates 4 to move synchronously. The two clamping plates 4 can clamp the piston from the side. The piston continues to move. At this time, the clamping plate 4 stops moving, and the push plate 5 moves towards the clamping plate 4 on the outer surface of the rod member 6. The first spring 7 is compressed, so as to clamp the piston.

[0038] When the support plate 3 moves downward, it contacts the pressure plate 24 and drives the pressure plate 24 to move synchronously. At this time, the support rod 26 penetrates the chute 8. The pressure plate 24 drives the push block 25 to rotate. The push block 25 drives the rack 22 to move synchronously through the mounting block 23. Since the rack 22 meshes with the toothed ring 21, the rack 22 can drive the column 12 to rotate through the toothed ring 21. At this time, the third spring 27 is compressed.

[0039] Meanwhile, the piston drives the sleeve 13 to move synchronously. In the initial state, under the action of the first magnet 14 and the second magnet 15, since the first magnet 14 and the second magnet 15 repel each other, the sleeve 13 moves away from the column 12. When the piston drives the sleeve 13 to move, at this time, the guide block 17 slides inside the guide groove 16. In the initial state, the positioning member 19 is located inside the groove 18. When the positioning member 19 moves to the position of the guide groove 16, the second spring 20 pushes the positioning member 19 out of the groove 18. At this time, the positioning member 19 passes through the guide groove 16 and contacts the inner wall of the piston. When the positioning member 19 moves to the position of the piston pin hole, the second spring 20 pushes the positioning member 19 through the piston pin hole.

[0040] When the piston is located above the support frame 2, under the action of gravity, the baffle 33 moves downward outside the fixed rod 34, and the baffle 33 is separated from the inner wall of the support frame 2, so that the air inside the support frame 2 can pass through the air outlet 32. At this time, the fourth spring 35 is deformed by force. When the piston rotates to the side and bottom of the support frame 2, under the elastic force of the fourth spring 35, the fourth spring 35 pushes the baffle 33 to contact the inner wall of the support frame 2, and the baffle 33 blocks the air outlet 32, so that the air inside the support frame 2 can only be conveyed from the upper air outlet 32. The fan 31 conveys the external air to the inside of the support frame 2 through the rotating member 29 and discharges it through the air outlet 32, and the air is conveyed to the inside of the piston.

[0041] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0042] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A positioning fixture for machining a diesel engine piston, comprising a base plate (1), characterized in that: A support frame (2) is arranged above the base plate (1), and the support frame (2) is connected to the base plate (1) via a rotating mechanism. A positioning mechanism is arranged outside the support frame (2), and the number of the positioning mechanisms is at least one group. The positioning mechanism comprises a support plate (3), and the support plate (3) is arranged above the support frame (2). Two groups of clamping plates (4) are slidably mounted on a side of the support plate (3) away from the support frame (2), and the clamping plates (4) are connected to the support frame (2) via a pushing device. A sleeve (13) is slidably penetrated inside the support frame (2), and a column (12) is slidably mounted inside the sleeve (13), and the column (12) penetrates below the sleeve (13). The sleeve (13) is rotatably connected to the support frame (2) via a rotating device, and two groups of positioning members (19) are mounted inside the sleeve (13) via an elastic device.

2. A positioning fixture for machining a diesel engine piston according to claim 1, characterized in that: The rotating mechanism comprises a rotating mechanism, the rotating mechanism comprising a vertical plate (28), the vertical plate (28) being fixedly mounted above the bottom plate (1), a motor (30) being fixedly mounted on a side of the vertical plate (28) away from the supporting frame (2), a rotating member (29) being fixedly mounted on an output end of the motor (30), the rotating member (29) being connected to the supporting frame (2), a fan (31) being fixedly mounted on an end of the rotating member (29) away from the supporting frame (2), an air outlet (32) being provided on the outside of the supporting frame (2), and the air outlet (32) being connected to the column (12).

3. A positioning fixture for machining a diesel engine piston according to claim 2, characterized in that: A fixing rod (34) is fixedly installed inside the support frame (2); a baffle (33) is slidably sleeved on the outer surface of the fixing rod (34); the area of ​​the baffle (33) is larger than the area of ​​the air outlet (32); a No. 4 spring (35) is movably sleeved on the outer surface of the fixing rod (34); the No. 4 spring (35) and the baffle (33) are fixedly connected.

4. A positioning fixture for machining a diesel engine piston according to claim 1, characterized in that: The pushing device comprises a push plate (5), wherein the push plates (5) are in two groups, and the two groups of push plates (5) are respectively located at a side away from the two groups of clamping plates (4). A rod (6) is slidably penetrated inside the push plate (5), and the rod (6) and the clamping plate (4) are fixedly connected. A spring (7) is movably sleeved on the outer surface of the rod (6), and the spring (7) is located between the clamping plate (4) and the push plate (5). The push plate (5) is connected to the support plate (3) via a sliding assembly.

5. A positioning fixture for machining a diesel engine piston according to claim 4, characterized in that: The sliding assembly comprises a slide groove (8), wherein the slide groove (8) is arranged inside the support plate (3), a slider (9) is slidably mounted inside the slide groove (8), the slider (9) is fixedly connected to the clamp plate (4), an elastic member (10) is fixedly mounted inside the slide groove (8), the elastic member (10) is connected to the slider (9), a connecting plate (11) is rotatably mounted below the slider (9), an end of the connecting plate (11) away from the slider (9) is fixedly connected to the surface of the support frame (2), and the connecting plate (11) is inclined.

6. A positioning fixture for machining a diesel engine piston according to claim 1, characterized in that: The rotating device comprises a gear ring (21) and a rack (22); the gear ring (21) is fixedly sleeved on the outside of the column (12); the gear ring (21) is rotatably connected to the support frame (2); the rack (22) is slidably mounted above the support frame (2); the rack (22) and the gear ring (21) are meshed; the rack (22) is connected via a pushing assembly including a support plate (3).

7. A positioning fixture for machining a diesel engine piston according to claim 6, characterized in that: The pushing assembly comprises a pressing plate (24), wherein the pressing plate (24) is connected to the supporting frame (2) via a lifting structure, and the pressing plate (24) is located between the supporting plate (3) and the rack (22). A mounting block (23) is fixedly mounted above the rack (22), and a pushing block (25) is rotatably mounted above the mounting block (23). An end of the pushing block (25) away from the mounting block (23) is rotatably connected to the pressing plate (24).

8. A positioning fixture for machining a diesel engine piston according to claim 7, characterized in that: The lifting structure comprises a support rod (26), wherein the support rod (26) is fixedly mounted on the outer surface of the support frame (2), the support rod (26) and the pressure plate (24) are slidably connected, a No. 3 spring (27) is movably sleeved on the outer surface of the support rod (26), and the No. 3 spring (27) and the pressure plate (24) are fixedly connected.

9. A positioning fixture for machining a diesel engine piston according to claim 1, characterized in that: The elastic device comprises a groove (18), the groove (18) is opened inside the column (12), a second spring (20) is movably installed inside the groove (18), the second spring (20) and the positioning member (19) are fixedly connected, and the positioning member (19) and the groove (18) are slidably connected.

10. The positioning fixture for machining a diesel engine piston according to claim 1, characterized in that: The elastic device further comprises a guide groove (16) and a guide block (17); the guide groove (16) is provided outside the sleeve (13); the guide block (17) is fixedly connected to the outer surface of the column (12); the guide block (17) and the guide groove (16) are slidably connected; the guide groove (16) and the positioning member (19) are plug-fitted; a second magnet (15) is fixedly mounted above the column (12); a first magnet (14) is fixedly mounted inside the sleeve (13); the first magnet (14) and the second magnet (15) repel each other.

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