Vacuum circuit breaker driven by lever sliding

Abstract

A vacuum circuit breaker driven by lever sliding comprises a shell, a rotating main shaft and a vacuum arc-extinguishing chamber are arranged in the shell, the rotating main shaft drives the vacuum arc-extinguishing chamber to open and close through a driving structure, and the driving structure comprises a driving lever linked with the rotating main shaft. The driving lever is provided with a rotating center O, an input end A linked with the rotating main shaft and an output end B linked with the vacuum arc-extinguishing chamber, the rotating main shaft drives the input end A of the driving lever to rotate around the rotating center O through rotating action, the output end B is driven to move by utilizing a lever effect, and then the vacuum arc-extinguishing chamber is driven to realize closing and opening actions; and a force arm OA formed by the rotating center O and the input end A is longer than a force arm OB formed by the rotating center O and the output end B.

Description

Technical Field

[0001] This utility model relates to a lever-driven vacuum circuit breaker, belonging to the field of circuit breakers. Background Technology

[0002] Vacuum circuit breakers are named for their high vacuum conditions, which are the arc-extinguishing medium and the insulating medium between the contacts after arc extinguishing. They have the advantages of small size, light weight, suitability for frequent operation, and no need for maintenance during arc extinguishing, and are widely used in power distribution networks.

[0003] For example, Chinese utility model patent CN214254244U discloses a vacuum circuit breaker, characterized in that the transmission mechanism includes: a cam, which is connected to the rotating main shaft for transmission, and the cam is provided with an oblong hole; a linkage shaft, which is inserted into the oblong hole; a pre-tightening cover, the first end of which is fixedly connected to the linkage shaft; a guide shaft, one end of which is fixedly connected to the second end of the pre-tightening cover, and the other end of the guide shaft is connected to the moving end; and an elastic element, which is sleeved on the outer wall of the guide shaft, the first end of which abuts against the second end of the pre-tightening cover, and the second end of the elastic element abuts against the moving end. This structure uses a cam to drive the arc-extinguishing chamber. However, the drawback of using a cam structure is that as the breaking current of the circuit breaker increases (early vacuum circuit breakers had a breaking current of 16kA, corresponding to a contact pressure of approximately 1000N–1200N; later, the breaking current increased to 20kA, corresponding to a contact pressure of 1600N–1800N), the circuit breaker experiences varying degrees of tripping failure during power system operation, i.e., refusal to trip. Upon inspection of the vacuum circuit breaker, the cam structure's slide, which drives the moving contact, forms a pit in the corresponding position of the slide when in the closed position due to the excessive force of the contact pressure spring. When the mechanism drives the insulated hexagonal shaft, the pit in the slide jams the cam's rotation, preventing the pull rod from pulling the moving contact to perform a linear tripping action. This results in a large number of "refusal to trip" faults in similar circuit breakers. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a lever-driven vacuum circuit breaker.

[0005] A lever-driven vacuum circuit breaker includes a housing, within which a rotating main shaft and a vacuum interrupter are housed. The rotating main shaft drives the vacuum interrupter to close and open via a drive structure. The drive structure includes a drive lever linked to the rotating main shaft. The drive lever has a rotation center O, an input end A linked to the rotating main shaft, and an output end B linked to the vacuum interrupter. The rotating main shaft, through rotation, drives the input end A of the drive lever to rotate around the rotation center O, and utilizes the lever effect to move the output end B, thereby driving the vacuum interrupter to close and open. The lever arm OA formed by the rotation center O and the input end A is longer than the lever arm OB formed by the rotation center O and the output end B. In this invention, when in the closed state, the pressure spring of the vacuum interrupter contact can provide a force value in the same direction as the opening movement. When the circuit breaker operating mechanism trips, the force of the contact pressure spring in the closed state can create a pre-acceleration for the opening action of the moving contact. Similarly, in the open state, the drive lever must overcome the closing self-closing force generated by the moving contact of the vacuum interrupter. Therefore, in the initial stage of the closing action, the self-closing force of the moving contact can also provide an initial incremental acceleration for the closing speed of the moving contact. By fully utilizing the force characteristics of the vacuum interrupter in the open and closed states, positive drive is achieved, completely eliminating fault factors that cause the circuit breaker to fail to open or close.

[0006] Preferably, the rotation center O of the drive lever is connected to a guide gantry fixed inside the housing. The vacuum interrupter is connected to a drive rod for opening and closing the circuit breaker. The other end of the drive rod is connected to the output end B of the drive lever. The drive structure also includes a drive arm fixed on the rotating main shaft, which is connected to the input end A of the drive lever. The connection between the rotation center O of the drive lever and the guide gantry fixed inside the housing ensures the stability of the lever's movement. The connection between the drive rod and the drive arm further simplifies the structure, reduces manufacturing difficulty and cost, and improves the convenience of assembly and maintenance.

[0007] Furthermore, the drive lever end is provided with a first groove for setting input end A, and the drive arm is rotatably connected to the first groove via a first drive pin; the drive lever is provided with a second groove for setting input end B, and the drive rod is connected to the second groove via a second drive pin; the drive lever is provided with a third connecting hole for setting rotation center O, and the guide gantry is rotatably connected to the third connecting hole via a third drive pin. The first groove can effectively guide the movement of the first drive pin, optimize the force transmission, and enable the drive arm to effectively drive the drive lever to rotate to achieve opening and closing operations. The design of the second groove allows for more uniform force transmission during the movement of the drive rod, reducing local wear or jamming caused by force concentration, thereby improving the overall stability of the switching operation of the moving contact. The connection between the second groove and the second drive pin can improve the movement efficiency of the drive rod, enabling it to respond to control signals faster during closing and opening, and reducing mechanical delay. The design of the third connecting hole allows the guide gantry to be more securely connected to the drive lever, enhancing the stability of the entire drive system and ensuring consistent performance under high load or frequent operation.

[0008] Preferably, the first slide, the second slide, and the third connecting hole are arranged in a triangular pattern, with the line connecting the first slide and the third connecting hole aligned parallel to the long axis of the first slide. This triangular design provides a more rational mechanical structure, allowing the load to be distributed more evenly to each connection point when driving the lever. In particular, the parallel alignment of the long axis connecting lines between the first slide and the third connecting hole effectively reduces additional wear and structural fatigue caused by uneven force. The triangular configuration also helps ensure a more rational stress distribution among the slides and connecting holes during operation, effectively dispersing the load, reducing stress concentration, and thus improving the durability and reliability of the equipment.

[0009] Preferably, the guide gantry is provided with a sliding groove arranged along the opening and closing operation direction of the vacuum interrupter, and the drive rod is slidably connected to the sliding groove via a second drive pin. Guided by the sliding groove, the drive rod can achieve smoother movement, helping it stay on the correct guide path and ensuring that the contacts can accurately close or open during the opening and closing operation.

[0010] Furthermore, the sliding groove is vertical, allowing the drive lever to rotate and push the drive rod to slide within the sliding groove for opening and closing operations. The second sliding groove is vertically aligned with the sliding groove when the circuit is open. The arrangement of the sliding groove and the second sliding groove enables the drive lever to rotate and push the drive rod to move up and down within the sliding groove, thereby performing opening and closing operations.

[0011] Preferably, the vacuum interrupter is provided with a fixed bracket at its bottom, and a conductive copper contact is provided between the fixed bracket and the vacuum interrupter; a guide plate is provided at the moving end of the vacuum interrupter. The conductive copper contact effectively ensures smooth current conduction from the vacuum interrupter to the outside, thereby improving the overall conductivity of the equipment. The fixed bracket provides solid mechanical support for the vacuum interrupter, enhancing the structural stability of the entire equipment.

[0012] Preferably, the top of the vacuum interrupter is provided with a flexible connection, the drive rod is covered with an elastic element that abuts against the flexible connection, and the other end of the elastic element is connected to a pressure sleeve, which is sleeved on the outside of the drive rod.

[0013] Furthermore, the drive levers are distributed on both sides of the guide gantry, and the pressure sleeve is provided with a positioning groove for engaging with the guide gantry. The pressure sleeve is also provided with a through hole, through which the second drive pin passes and connects to the second sliding grooves on the drive levers on both sides. This dual-sided configuration of the drive levers allows for better coordination and cooperation between the left and right sides, ensuring synchronization of all parts during operation, thereby improving the overall efficiency and accuracy of the system.

[0014] The beneficial effects of this utility model are as follows: This utility model adopts a lever structure, effectively resolving the problem of the huge operating reaction force on the operating mechanism caused by the extremely high pressure of the contact pressure spring in the traditional four-bar drive structure. Simultaneously, the extremely high contact pressure in the closed state also meets the corresponding structural rigidity requirements of the rotating main shaft and the insulating crank arm. This simplifies the structural rigidity while continuing the traditional four-bar transmission method, ensuring smooth operation in both closing and opening states. It is particularly effective in solving the contact pressure problem of vacuum circuit breakers with short-circuit currents greater than 25kA, completely eliminating the jamming problem in closing and opening operations. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of this utility model.

[0016] Figure 1 This is a structural diagram of the main body of this utility model;

[0017] Figure 2 This is a structural diagram of the present invention with part of the outer shell removed;

[0018] Figure 3 This is a partial structural diagram of the present invention;

[0019] Figure 4 for Figure 3 A structural diagram with parts of the structure removed;

[0020] Figure 5 for Figure 4 Enlarged detail view of point A in the middle;

[0021] Figure 6 for Figure 4 A structural diagram with parts of the structure removed;

[0022] Figure 7 for Figure 6 Enlarged detail view of point B in the middle;

[0023] Figure 8 A structural diagram of the driving lever;

[0024] Figure 9 This is a structural diagram of the guide gantry;

[0025] In the diagram, 1. Outer shell; 2. Rotating spindle; 3. Vacuum interrupter; 31. Drive rod; 32. Second drive pin; 33. Fixed bracket; 34. Conductive copper contact; 35. Guide plate; 36. Flexible connection; 37. Elastic element; 38. Pressure sleeve; 381. Positioning groove; 382. Through hole; 4. Drive structure; 41. Drive lever; 411. First slide groove; 412. Second slide groove; 413. Third connecting hole; 42. Drive arm; 421. First drive pin; 5. Guide gantry; 51. Third drive pin; 52. Sliding groove; 53. Pivot hole. Detailed Implementation

[0026] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0027] It should be noted that all uses of "first" and "second" in the embodiments of this utility model are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of this utility model. Subsequent embodiments will not explain this in detail.

[0028] The directional and positional terms used in this utility model, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are merely for reference to the accompanying drawings. Therefore, the directional and positional terms used are for the purpose of explaining and understanding this utility model, and not for limiting the scope of protection of this utility model.

[0029] like Figure 1-9The diagram illustrates an embodiment of a lever-driven vacuum circuit breaker according to this invention. It includes a housing 1, within which a rotating main shaft 2 and a vacuum interrupter 3 are housed. The rotating main shaft 2 drives the vacuum interrupter 3 to close and open via a drive structure 4. The drive structure 4 includes a drive lever 41 linked to the rotating main shaft 2. The drive lever 41 has a rotation center O, an input end A linked to the rotating main shaft 2, and an output end B linked to the vacuum interrupter 3. The rotating main shaft 2, through its rotational motion, drives the input end A of the drive lever 41 to rotate around the rotation center O, thereby using the lever effect to move the output end B, and thus driving the vacuum interrupter 3 to achieve the closing and opening actions. The lever arm OA formed by the rotation center O and the input end A is longer than the lever arm OB formed by the rotation center O and the output end B. In this invention, when the circuit is closed, the pressure spring of the vacuum interrupter 3 contact can provide a force value consistent with the direction of the opening movement. When the circuit breaker operating mechanism trips, the force of the contact pressure spring in the closed state creates a pre-acceleration for the moving contact during its tripping action. Similarly, in the open state, the drive lever 41 must overcome the closing self-closing force generated by the moving contact of the vacuum interrupter 3. Therefore, in the initial stage of the closing action, the self-closing force of the moving contact can also provide an initial incremental acceleration for the closing speed of the moving contact. By fully utilizing the force characteristics of the vacuum interrupter 3 in both the open and closed states, positive drive is achieved, completely eliminating fault factors that could cause the circuit breaker to fail to open or close.

[0030] Utilizing the lever effect, the rotation of the main shaft 2 is transmitted to the vacuum interrupter 3 via the drive lever 41, with a difference in the lever arm length between the input and output ends (OA>OB). This design effectively amplifies the driving force, enabling the moving contact to move rapidly during opening and closing, thus improving the efficiency and reliability of the opening and closing actions. In the closed state, the force of the contact pressure spring in the vacuum interrupter 3 is in the same direction as the opening direction.

[0031] The rotation center O of the drive lever 41 is connected to the guide gantry 5 fixed inside the housing 1. The vacuum interrupter 3 is connected to a drive rod 31 for opening and closing the circuit breaker. The other end of the drive rod 31 is connected to the output end B of the drive lever 41. The drive structure 4 also includes a drive arm 42 fixed on the rotating main shaft 2, which is connected to the input end A of the drive lever 41. The connection between the rotation center O of the drive lever 41 and the guide gantry 5 fixed inside the housing 1 ensures the stability of the lever's movement. The connection between the drive rod 31 and the drive arm 42 further simplifies the structure, reduces manufacturing difficulty and cost, and improves the convenience of assembly and maintenance.

[0032] The drive lever 41 has a first groove 411 at its end for setting the input end A, and the drive arm 42 is rotatably connected to the first groove 411 via a first drive pin 421. The drive lever 41 has a second groove 412 for setting the input end B, and the drive rod 31 is connected to the second groove 412 via a second drive pin 32. The drive lever 41 has a third connecting hole 413 for setting the rotation center O, and the guide gantry 5 is rotatably connected to the third connecting hole 413 via a third drive pin 51. The first groove 411 can effectively guide the movement of the first drive pin 421, optimize the force transmission, and enable the drive arm 42 to effectively drive the drive lever 41 to rotate and achieve the opening and closing operation. The design of the second groove 412 can make the force transmission of the drive rod 31 more uniform during the movement of the mechanism, reduce the local wear or jamming caused by force concentration, and thus improve the overall stability of the switching operation of the moving contact. The second slide 412, through its connection with the second drive pin 32, improves the motion efficiency of the drive lever 31, enabling it to respond to control signals more quickly during closing and opening, and reducing mechanical delay. The design of the third connecting hole 413 allows the guide gantry 5 to be more securely connected to the drive lever 41, enhancing the stability of the entire drive system and ensuring consistent performance under high loads or frequent operations.

[0033] The first slide groove 411, the second slide groove 412, and the third connecting hole 413 are arranged in a triangular pattern, with the connecting line between the first slide groove 411 and the third connecting hole 413 aligned parallel to the long axis of the first slide groove 411. This triangular design provides a more rational mechanical structure, allowing the load to be distributed more evenly to each connection point when the lever 41 is driven to move. In particular, the parallel alignment of the long axis connecting lines between the first slide groove 411 and the third connecting hole 413 effectively reduces additional wear and structural fatigue caused by uneven force. The triangular configuration helps ensure a more rational stress state for each slide groove and connecting hole during operation, effectively distributing the load, reducing stress concentration, and thus improving the durability and reliability of the equipment.

[0034] The guide gantry 5 is provided with a sliding groove 52 arranged along the opening and closing operation direction of the vacuum interrupter 3. The drive rod 31 is slidably connected to the sliding groove 52 through the second drive pin 32. Guided by the sliding groove 52, the drive rod 31 can achieve more stable movement, helping the drive rod 31 to stay on the correct guide path, ensuring that the contacts can accurately close or open during the opening and closing operation.

[0035] The guide gantry 5 is provided with a fulcrum hole 53, which matches the third connecting hole 413 and is rotatably connected with the third drive pin 51. A graphite-lubricated sliding bearing is installed here.

[0036] The sliding groove 52 is vertical, allowing the drive lever 41 to rotate and push the drive rod 31 to slide within the sliding groove 52 for opening and closing operations. The second sliding groove 412 is vertically aligned with the sliding groove 52 when the circuit is open. The arrangement of the sliding groove 52 and the second sliding groove 412 enables the drive lever 41 to rotate and push the drive rod 31 up and down within the sliding groove 52, thereby performing opening and closing operations.

[0037] The vacuum interrupter 3 has a fixed support 33 at its bottom, and a conductive copper contact 34 is provided between the fixed support 33 and the vacuum interrupter 3. A guide plate 35 is provided at the moving end of the vacuum interrupter 3. The conductive copper contact 34 effectively ensures smooth current conduction from the vacuum interrupter 3 to the outside, thereby improving the overall conductivity of the equipment. The fixed support 33 provides solid mechanical support for the vacuum interrupter 3, enhancing the structural stability of the entire equipment.

[0038] The fixed bracket 33 secures the static conductive end of the arc-extinguishing chamber to the conductive copper contact 34 with two nuts, thereby enabling current conduction.

[0039] The top of the vacuum interrupter 3 is provided with a flexible connection 36, and the drive rod 31 is covered with an elastic element 37 that abuts against the flexible connection 36. The other end of the elastic element 37 is connected to a pressure sleeve 38, which is sleeved on the outside of the drive rod 31.

[0040] The flexible connector 36 is connected to the moving conductive end of the vacuum interrupter 3 to enable current conduction at the moving end of the vacuum interrupter 3.

[0041] The drive levers 41 are distributed on both sides of the guide gantry 5. The pressure sleeve 38 is provided with a positioning groove 381 for engaging with the guide gantry 5. The pressure sleeve 38 is also provided with a through hole 382. The second drive pin 32 passes through the through hole 382 and connects to the second sliding groove 412 on the drive levers 41 on both sides. The design of the drive levers 41 being configured on both sides allows for better coordination and cooperation between the movements of the left and right sides, ensuring the synchronicity of various parts during operation, thereby improving the overall efficiency and accuracy of the system.

[0042] The opening and closing operations of a vacuum circuit breaker shall be performed in the following sequence:

[0043] 1. Circuit Breaker Closing Operation. Facing the front panel of the switch, the circuit breaker's operating mechanism outputs a clockwise rotation angle. By rotating the main shaft 2, it drives the drive arm 42 to rotate clockwise at the same angle. When the drive arm 42 rotates, the second drive pin 32 moves in the corresponding groove of the drive lever 41, pushing the drive lever 41 to swing downward around the third drive pin 51, which in turn pushes the lever against the second drive pin 32. The second drive pin 32 pushes the drive rod 31 downward along the middle groove of the guide gantry 5, causing the moving contact of the vacuum interrupter 3 to move downward, so that the moving and stationary contacts make contact first. Then, it continues to move downward, pushing the pressure sleeve 38 and compressing the contact pressure spring, so that the moving and stationary contacts have a certain closing contact pressure after contact. The closing operation of the vacuum circuit breaker is completed.

[0044] 2. For circuit breaker tripping operation, the reverse motion is performed. Facing the front panel of the switch, the circuit breaker's operating mechanism outputs a counter-clockwise rotation angle, which drives the drive arm 42 to rotate counter-clockwise at the same angle by rotating the main shaft 2. When the drive arm 42 rotates counter-clockwise, the second drive pin 32 moves in the corresponding groove of the drive lever 41, pushing the drive lever 41 to swing upward around the third drive pin 51, which in turn pushes the lever against the second drive pin 32. The second drive pin 32 pulls up the pressure sleeve 38 along the middle sliding groove 52 of the guide gantry 5, first releasing the contact pressure value in the closed state of the circuit breaker. Then, the second drive pin 32 continues to move upward, pulling up the drive rod 31, which drives the moving contact of the vacuum interrupter 3 to move upward, separating the moving contact from the stationary contact. It continues to move upward, forming an insulation gap between the moving and stationary contacts. A certain separation distance "opening gap size requirement" is required to ensure the required break insulation strength of the circuit breaker in the tripping state. The tripping operation of the vacuum circuit breaker is completed.

[0045] In contrast, ABB's similar vacuum circuit breaker uses a cam structure constructed from a sliding groove, driven by an insulated hexagonal shaft. In ABB's cam-based sliding groove structure, the contact pressure required by the moving contact of the vacuum interrupter in the closing state, and the self-closing force of the moving contact in the opening state, are perpendicular to the cam's rotational direction at a 90-degree angle. The greater the force of the interrupter, the greater the frictional resistance torque caused by this force in the normal direction. This inevitably leads to resistance torque causing the operating mechanism to fail to open or close. This invention completely eliminates this frictional resistance torque formation mechanism, designing a positive energy operating trend.

[0046] The driving device involved in this utility model is applied to the field of vacuum circuit breakers, but is not limited to the application of vacuum circuit breakers. It can be extended to all vacuum load switches and vacuum contactors that use vacuum interrupters.

[0047] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.

[0048] Although the present invention has been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the specific embodiments disclosed. The present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A lever-driven vacuum circuit breaker, characterized in that: The device includes a housing, within which a rotating main shaft and a vacuum interrupter are located. The rotating main shaft drives the vacuum interrupter to close and open via a drive structure. The drive structure includes a drive lever linked to the rotating main shaft. The drive lever has a rotation center O, an input end A linked to the rotating main shaft, and an output end B linked to the vacuum interrupter. The rotating main shaft drives the input end A of the drive lever to rotate around the rotation center O through rotation, and uses the leverage effect to drive the output end B to move, thereby driving the vacuum interrupter to achieve the closing and opening action. The lever arm OA formed by the rotation center O and the input end A is longer than the lever arm OB formed by the rotation center O and the output end B.

2. The lever-driven vacuum circuit breaker as described in claim 1, characterized in that: The rotation center O of the drive lever is connected to the guide gantry fixed inside the housing. The vacuum interrupter is connected to a drive rod for opening and closing the circuit breaker. The other end of the drive rod is connected to the output end B of the drive lever. The drive structure also includes a drive arm fixed on the rotating main shaft. The drive arm is connected to the input end A of the drive lever.

3. The lever-driven vacuum circuit breaker as described in claim 2, characterized in that: The drive lever has a first groove at its end for setting the input end A, and the drive arm is rotatably connected to the first groove via a first drive pin; the drive lever has a second groove for setting the input end B, and the drive rod is connected to the second groove via a second drive pin; the drive lever has a third connecting hole for setting the rotation center O, and the guide gantry is rotatably connected to the third connecting hole via a third drive pin.

4. The lever-driven vacuum circuit breaker as described in claim 3, characterized in that: The first slide, the second slide, and the third connecting hole are arranged in a triangular pattern, and the connecting line between the first slide and the third connecting hole is parallel and aligned with the long axis of the first slide.

5. The lever-driven vacuum circuit breaker as described in claim 2, characterized in that: The guide gantry is provided with a sliding groove arranged along the opening and closing operation direction of the vacuum interrupter, and the drive rod is slidably connected to the sliding groove through a second drive pin.

6. The lever-driven vacuum circuit breaker as described in claim 5, characterized in that: The sliding groove is vertical, so that the drive lever pushes the drive rod to slide in the sliding groove to perform the opening and closing operation by rotating. The second sliding groove is vertical relative to the sliding groove in the opening state.

7. The lever-driven vacuum circuit breaker as described in claim 1, characterized in that: The vacuum interrupter is provided with a fixed support at the bottom, and a conductive copper contact is provided between the fixed support and the vacuum interrupter; the moving end of the vacuum interrupter is provided with a guide plate.

8. The lever-driven vacuum circuit breaker as described in claim 3, characterized in that: The top of the vacuum interrupter is provided with a flexible connection, and the drive rod is covered with an elastic element that abuts against the flexible connection. The other end of the elastic element is connected to a pressure sleeve, which is fitted onto the outside of the drive rod.

9. The lever-driven vacuum circuit breaker as described in claim 8, characterized in that: The drive levers are distributed on both sides of the guide gantry. The pressure sleeve is provided with a positioning groove for engaging with the guide gantry. The pressure sleeve is provided with a through hole. The second drive pin passes through the through hole and connects with the second sliding groove on the drive levers on both sides.

Images