A tool for cutting and bending the tail of a cotter pin

Abstract

The present invention discloses a tool for cutting and bending the tail of a cotter pin. A movable jaw body is rotatably fixed to a fixed jaw body via a jaw shaft. Steps I and II are respectively raised on opposing surfaces of the upper ends of the fixed and movable jaw bodies. The inner end planes I and II of the fixed and movable jaw bodies at steps I and II are arranged oppositely. The inner end surface of a positioning block fixed within a through slot I of the fixed jaw body protrudes from the inner end plane I of the fixed jaw body. A central positioning block is positioned within a dovetail groove of the positioning block, with its front end capable of extending into and abutting against a cotter pin fixing groove of a workpiece nut. The front end of an adjusting screw threaded into the positioning block is fixed within the central positioning block. A protrusion with a cutting edge protrudes from one end of a conversion head body. The conversion head body is detachably fixed within through slot II of the movable jaw body. This device does not damage the threads during assembly, improving assembly quality. It is less restricted by radial space between bolts, making assembly simple and convenient. It is suitable for nut and cotter pin assemblies of various specifications.

Description

Technical Field

[0001] The invention belongs to the field of mechanical assembly and relates to a tool for cutting and bending the tail of a cotter pin. Background Art

[0002] The most common threaded connection method is a bolt and nut combination. Under static loads and with minimal fluctuations in operating temperature, these connections will not loosen on their own. However, under shock, vibration, or variable loads, as well as under significant temperature fluctuations, these connections may loosen, impacting operation and even causing accidents. To ensure safe and reliable connections, effective anti-loosening measures are often implemented. Cotter pins are widely used in the machinery industry and are the most common anti-loosening method.

[0003] The material of the cotter pin is usually austenitic stainless steel 0Cr18Ni9Ti and 1Cr18Ni9Ti. It is a metal hardware, commonly known as a spring pin, used to prevent threaded connections from loosening. The cotter pin is inserted into the nut groove and the hole at the tail of the bolt, and the tail of the cotter pin is broken open and bent into the nut groove to prevent the nut and bolt from rotating relative to each other.

[0004] The general method for installing a cotter pin is to manually pry apart the two legs after inserting the cotter pin. Depending on the size and hardness of the cotter pin, bend it with pliers or by hand until the two legs are flush against the outer hexagonal edge of the nut. Finally, use a hammer and a flat-blade screwdriver or chisel to remove any excess material and bend the tail end into the groove of the hexagonal slot nut. This method is currently the most commonly used, but it is difficult to control the force and can easily damage the threads. Furthermore, the flat-blade screwdriver or chisel must be perpendicular to the thread axis, which is limited by the radial space of the bolt. Summary of the Invention

[0005] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide a tool for cutting and bending the tail of a cotter pin. When assembling the cotter pin to prevent the nut and bolt from rotating relative to each other, the device will not damage the threads of the bolt and the nut, thereby improving the assembly quality. The device is less restricted by the radial space of the bolt and is simple and convenient to assemble. It can be applied to nut and cotter pin assemblies of various specifications.

[0006] To achieve the above-mentioned purpose, the technical solution of the present invention is: a split pin tail cutting and bending tool, comprising a fixed part, a movable part and a clamp shaft; the fixed part comprises a fixed clamp body, a fixed shaft, a center positioning block, a positioning block and an adjusting screw; the movable part comprises a movable clamp body, a connecting shaft and a conversion head; the vertical cross-section of the fixed clamp body is in the shape of a "ㄣ", and the movable clamp body is a rectangular parallelepiped, and the two are connected by a clamp shaft in the middle, one end of the clamp shaft is fixed to the fixed clamp body, and the other end is rotatably fixed to the movable clamp body; steps I and II are raised on the opposite surfaces of the upper ends of the fixed clamp body and the movable clamp body, respectively, and the steps are The inner end plane I of the fixed pliers body at step I and the inner end plane II of the movable pliers body at step II are arranged opposite to each other; the upper ends of the fixed pliers body and the movable pliers body at step I and step II are respectively provided with a through slot I matching the positioning block and a through slot II matching the conversion head body; the positioning block is fixed in the through slot I of the fixed pliers body by a fixed shaft and its inner end face opposite to the workpiece nut protrudes from the inner end plane I of the fixed pliers body; the center positioning block is dovetail-shaped with a small front end and a large rear end; the inner end face of the positioning block is provided with a step III that fits with the lower end face of the workpiece nut, and the positioning block at the upper end of step III is provided with a through slot that penetrates the upper end face and fits with the rear end face of the center positioning block A dovetail groove with clearance fit; a threaded hole perpendicular to the bottom wall of the dovetail groove and matching with the adjusting screw is provided on the bottom wall of the dovetail groove; the rear end of the center positioning block is placed in the dovetail groove, and its front end can extend into and abut against the cotter pin fixing groove of the workpiece nut, and a threaded groove is provided on its rear end; the adjusting screw is threadedly connected to the threaded hole of the positioning block, and the front end is fixed in the threaded groove of the center positioning block; the conversion head includes a conversion head body, and the conversion head body protrudes a protrusion with an angular front end at one end relative to the workpiece nut; the front end of the protrusion is a bent inclined surface, and the plane in contact with the cotter pin is the extrusion surface, and the front of the intersection of the bent inclined surface and the opposite surface of the extrusion surface A blade is provided on the edge, the thickness of the protrusion and the radius of the cotter pin add up to match the width of the cotter pin fixing groove of the workpiece nut, and a slot entry limit mechanism is provided on the protrusion; the conversion head body is detachably fixed in the through slot Ⅱ of the movable pliers body by the connecting shaft, and the bent inclined surface on the protrusion is arranged parallel to the inner end face of the positioning block; when working, the positioning block of the fixed pliers body and the workpiece nut are adsorbed together, and the center positioning block is pressed against a cotter pin fixing groove of the workpiece nut but has a distance from the workpiece bolt, and the protrusion of the conversion head can squeeze one end of the cotter pin into the other opposite cotter pin fixing groove of the workpiece nut and has a distance from the workpiece bolt.

[0007] Further preferably, the specific structure in which one end of the clamp shaft is fixed to the fixed clamp body and the other end is rotatably fixed to the movable clamp body is: one end of the clamp shaft is a cylindrical shaft, and the other end is a spline shaft with one or more key protrusions; the middle relative positions of the fixed clamp body and the movable clamp body are respectively provided with mounting hole I that matches the spline shaft of the clamp shaft and mounting hole II that gap matches the cylindrical shaft of the clamp shaft; one end of the clamp shaft passes through the mounting hole I of the fixed clamp body, and the other end passes through the mounting hole II of the movable clamp body, and both ends are riveted to the fixed clamp body and the movable clamp body.

[0008] Further preferably, the specific structure in which the positioning block is fixed in the through slot I of the fixed caliper body by a fixed shaft is: a fixing hole and a fixed through hole are respectively provided on the positioning block and the two end walls of the through slot I, and the fixed shaft is interference fitted in the fixing hole and the fixed through hole.

[0009] Further preferably, the movable part also includes an elastic retaining ring; one end of the connecting shaft is a square shaft and the other end is a cylindrical shaft, and a connecting shaft mounting hole with a square hole at one end and a round hole at the other end is provided on the conversion head body, and a through square hole and a through round hole are respectively provided on the two walls of the through slot II of the movable clamp body at positions corresponding to the connecting shaft mounting hole of the conversion head body; the conversion head body is placed in the through slot II, and is fixed on the two walls of the through slot II by the connecting shaft and the elastic retaining ring clamped on the end of the cylindrical shaft of the connecting shaft.

[0010] Further preferably, the angle between the bending slope of the conversion head and the opposite surface of the extrusion surface is less than 90 degrees, so as to ensure the convenience of the blade cutting.

[0011] Further preferably, the slot-entry limiting mechanism provided on the protrusion of the conversion head is configured such that: the extrusion surface is inclined at an angle of 5 to 10 degrees relative to the plane of the side edge of the workpiece nut groove, so that the thickness of the protrusion ensures that the cotter pin cannot move into the workpiece nut groove when it is squeezed into place; or the slot-entry limiting mechanism provided on the protrusion of the conversion head is configured such that a stop protrusion is provided on the convex extrusion surface and the surface opposite the extrusion surface. This provides high strength and prevents the protrusion from continuing to enter the groove after the conversion head bends the cotter pin into place, thereby damaging the threads of the bolt and nut.

[0012] Further preferably, the structure in which the positioning block of the fixed pliers body and the workpiece nut are attracted together is as follows: the positioning block is a permanent magnet, and the workpiece nut is made of a material that is attracted to magnets; the fixed pliers body, fixed shaft, center positioning block, adjustment screw, movable pliers body, connecting shaft, conversion head, and pliers shaft are made of materials that are not attracted to magnets. Preferably, the elastic retaining ring is made of a material that is not attracted to magnets. Since nuts and bolts are mostly made of iron or stainless steel that are attracted to magnets, as long as the positioning block is a permanent magnet, such nuts can be attracted, so that the fixed pliers body and the nut are accurately aligned, and the fixation is simple and reliable. However, this is not suitable for the use of nuts made of materials that are not attracted to magnets.

[0013] Further preferably, the structure in which the positioning block of the fixed pliers body and the workpiece nut are adsorbed together is as follows: sealing gaskets are fixed on the positioning block steps III on both sides of the positioning block dovetail groove, a through ventilation channel is opened in the positioning block, the through ventilation channel passes through the fixed pliers body to form an external ventilation port, and a pipe joint connected to a vacuum pump is fixed on the external ventilation port; ventilation holes are opened on the two sealing gaskets, and the ventilation holes on the two sealing gaskets are connected to the ventilation channel in the fixed pliers body. When in use, as long as the pipe joint is connected to the air pump, the position of the fixed block and the nut is adjusted and aligned and attached together, the vacuum pump is evacuated, the fixed block and the nut are tightly attached, and no more movement or misalignment occurs, then a series of operations such as tightening the center positioning block, opening the movable inlay, cutting, bending and squeezing the fixed cotter pin of the adapter, etc. are simple, convenient and efficient.

[0014] During use, the adjustment screw is rotated to adjust the length of the center locating block extending beyond the positioning block and the fixed jaw body, ensuring that the center locating block abuts the nut groove. The entire tool is moved and, after accurate alignment, the positioning block of the fixed jaw body and the workpiece nut are attracted together to ensure that the end face of the positioning block is aligned with the end face of the nut. The movable jaw body is gripped and rotated. The blades on the adapter head interact with the side of the nut groove to complete the shearing of the cotter pin. Simultaneously, the bend of the adapter head bends the cotter pin toward the nut groove, forcing the adapter head into the nut groove. Driven by the bend of the adapter head and pressed by its extrusion surface, the sheared end of the cotter pin is pressed against the side of the groove and compacted. The movable jaw body is then moved to disengage the nut, and the fixed jaw body is then disengaged from the workpiece nut. The above steps are repeated to cut, bend, and compact the other end of the cotter pin. The present invention achieves accurate alignment during cotter pin assembly without damaging the threads of the bolt or nut, improving assembly quality. Furthermore, due to minimal radial space restrictions on the bolt, assembly is simple and convenient, improving efficiency and saving labor. According to the different specifications of the nut, different types of conversion heads can be selected according to the size of the nut groove and the cotter pin. By replacing the conversion head, it can be applied to nut and cotter pin assemblies of various specifications, with a wide range of uses. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A front view of a first embodiment of the present invention;

[0016] Figure 2 This is an exploded view of the three-dimensional structure of the first embodiment of the present invention;

[0017] Figure 3 This is a front view of the first embodiment of the present invention when the workpiece processing has just been completed;

[0018] Figure 4 for Figure 3 AA cross-sectional view;

[0019] Figure 5 This is a schematic diagram of the three-dimensional structure of the fixing block in the first embodiment of the present invention;

[0020] Figure 6 This is a three-dimensional structural diagram of the center positioning block in the present invention;

[0021] Figure 7 It is a three-dimensional structural diagram of the clamp shaft in the present invention;

[0022] Figure 8 It is a three-dimensional structural diagram of the connecting shaft in the present invention;

[0023] Figure 9 This is a three-dimensional structural diagram of the conversion head of the present invention viewed from one direction;

[0024] Figure 10 This is a three-dimensional structural diagram of the conversion head of the present invention viewed from another direction;

[0025] Figure 11 It is a front view of a second embodiment of the present invention;

[0026] Figure 12 A top view of a second embodiment of the present invention;

[0027] Figure 13 for Figure 12 BB cross-sectional view;

[0028] Figure 14 This is an exploded view of the three-dimensional structure of the second embodiment of the present invention;

[0029] Figure 15 This is a front view of the second embodiment of the present invention when the workpiece processing has just been completed;

[0030] Figure 16 for Figure 15 CC cross-sectional view;

[0031] Figure 17 This is a schematic diagram of the three-dimensional structure of the fixing block in the second embodiment of the present invention viewed from one direction;

[0032] Figure 18 This is a schematic diagram of the three-dimensional structure of the fixing block in the second embodiment of the present invention viewed from another direction;

[0033] Figure 19 This is a schematic diagram of the three-dimensional structure of a sealing gasket in the second embodiment of the present invention;

[0034] Figure 20 A top view of a sealing gasket in a second embodiment of the present invention;

[0035] Figure 21 for Figure 20 DD cross-sectional view;

[0036] Figure 22 It is a left side view of the sealing gasket in the second embodiment of the present invention;

[0037] Figure 23 for Figure 22 EE cross-sectional view. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to the accompanying drawings and specific implementations.

[0039] Example 1, as Figure 1 Zhihe Figure 10As shown, this embodiment includes a fixed part 1, a movable part 2 and a clamp shaft 3. The fixed part 1 includes a fixed clamp body 101, a fixed shaft 107, a center positioning block 103, a positioning block 105 and an adjustment screw 104. The movable part includes a movable clamp body 201, a connecting shaft 202 and a conversion head 203. The vertical cross-section of the fixed pliers body 101 is in the shape of a "ㄣ", and the movable pliers body 201 is a rectangular parallelepiped, and the two are connected by a pliers shaft 3 in the middle; one end of the pliers shaft 3 is fixed to the fixed pliers body 101, and the other end is rotatably fixed to the movable pliers body 201; preferably, the specific structure is: one end of the pliers shaft 3 is a cylindrical shaft, and the other end is a spline shaft with a key (multiple keys can also be selected as needed, but because the object is small, the production process of multiple keys is cumbersome) protruding; the middle relative positions of the fixed pliers body 101 and the movable pliers body 201 are respectively provided with a mounting hole I109 that matches the spline shaft of the pliers shaft 3 and a mounting hole II207 that is clearance-matched with the cylindrical shaft of the pliers shaft 3; one end of the pliers shaft 3 is passed through the mounting hole I109 of the fixed pliers body, and the other end is passed through the mounting hole II207 of the movable pliers body, and both ends are riveted to the fixed pliers body 101 and the movable pliers body 201. The upper mounting surfaces of the fixed jaw body 101 and the movable jaw body 201 each have raised steps I 108 and II 206, respectively. The inner end plane I of the fixed jaw body 101 at step I 108 and the inner end plane II of the movable jaw body 201 at step II are positioned opposite each other. A through slot I 111, which mates with the positioning block 105, and a through slot II 212, which mates with the adapter body, are respectively formed at the upper ends of the fixed jaw body 101 and the movable jaw body 201 at steps I and II. The positioning block 105 is secured within the through slot I 111 of the fixed jaw body 101 by a fixed shaft 107, with its inner end surface opposite the workpiece nut 6 protruding beyond the inner end plane I of the fixed jaw body 101. A preferred specific structure is as follows: the lower end of the positioning block 105 and the end walls of the through slot I 111 each have a connecting fixing hole 113 and a fixing through hole 106, respectively. The fixed shaft 107 is interference-fitted within the fixing hole 113 and the fixing through hole 106. The center positioning block 103 is dovetail-shaped with a small front end and a large rear end. The inner end surface of the positioning block 105 has a step III 102 that mates with the lower end surface of the workpiece nut 6. Above step III 102, the positioning block 105 has a dovetail groove 110 that extends through the upper end surface and fits with the rear end of the center positioning block 103. The bottom wall of the dovetail groove 110 has a threaded hole 112 perpendicular to the bottom wall and mates with the adjustment screw 104. The rear end of the center positioning block 103 is positioned within the dovetail groove 110, while its front end can extend into and abut against the cotter pin fixing groove of the workpiece nut 6. The rear end has a threaded groove. The adjustment screw 104 is threaded into the threaded hole 112 of the positioning block, with its front end fixed within the threaded groove of the center positioning block 103.The conversion head 203 includes a conversion head body, and a protrusion with an angular front end protrudes from one end of the conversion head body relative to the workpiece nut 6; the front end of the protrusion is a bending slope 208, and the plane in contact with the cotter pin 4 is an extrusion surface 210. A blade 209 is provided on the front edge where the bending slope 208 intersects with the opposite surface of the extrusion surface 210. The thickness of the protrusion and the radius of the cotter pin 4 add up to match the width of the cotter pin fixing groove of the workpiece nut 6, and a slot limit mechanism is provided on the protrusion. The converter body is removably secured within the through-slot II 212 of the movable caliper 201 by a connecting shaft 202. A preferred specific structure includes a movable portion further comprising a circlip 205. The connecting shaft 202 has a square end and a cylindrical end. The converter body defines a connecting shaft mounting hole 204 with a square hole at one end and a circular hole at the other. The through-slot II 212 of the movable caliper 201 has a through-square hole and a through-circular hole, respectively, at positions corresponding to the connecting shaft mounting hole 204. The converter body is positioned within the through-slot II 212 and secured to the walls thereof by the connecting shaft 202 and a circlip 205 secured to the cylindrical end of the connecting shaft. The bend 208 on the protrusion of the converter body is parallel to the inner end plane I of the fixed caliper 101. Preferably, the angle between the bend 208 of the converter body and the extrusion surface 211 is less than 90°. The slot-entry limiter mechanism on the protrusion of the conversion head is configured such that the extrusion surface 210 is inclined at an angle of 5 to 10° relative to the plane 7 of the side of the groove of the workpiece nut 6. This ensures that the thickness of the protrusion prevents the cotter pin from moving into the workpiece nut groove when the cotter pin is pressed into place. (The slot-entry limiter mechanism on the protrusion of the conversion head can also be configured as a stop protrusion provided on the protrusion extrusion surface and the surface opposite the extrusion surface, as needed). During operation, the upper end of the fixed pliers body 101 and the workpiece nut 6 are attracted to each other. A preferred specific structure is as follows: the positioning block 105 is a permanent magnet, and the workpiece nut 6 is made of a material that is attracted to magnets. The fixed pliers body 101, fixed shaft 107, center positioning block 103, adjustment screw 104, movable pliers body 201, connecting shaft 202, conversion head 203, and pliers shaft 3 are made of materials that are not attracted to magnets. Preferably, the circlip 205 is also made of a material that is not attracted to magnets. During operation, the center positioning block 103 is pressed against a cotter pin fixing groove of the workpiece nut 6 but is spaced apart from the workpiece bolt 5. The protrusion of the conversion head 203 can squeeze one end of the cotter pin 4 into the other opposite cotter pin fixing groove of the workpiece nut 6 and is spaced apart from the workpiece bolt 5.

[0040] Example 2, as Figures 6 to 23As shown, the other structures of this embodiment are the same as those of Example 1. There are no material requirements for the positioning block, workpiece nut 6, fixed caliper body 101, fixed shaft 107, center positioning block 103, adjustment screw 104, movable caliper body 201, connecting shaft 202, conversion head 203, and caliper shaft 3. There are also no material requirements for the circlip 205. However, sealing gaskets 115 are fixed to the positioning block steps III 102 on both sides of the positioning block dovetail groove 110. Through-going vent passages 116 and 117 are defined within the positioning block 105. These through-going vent passages 116 and 117 extend through the fixed caliper body to form an external vent. A pipe joint 114 connected to a vacuum pump is fixed to this external vent. Multiple vent holes 118 are defined in each of the two sealing gaskets 115. The vent holes 118 on both sealing gaskets communicate with the vent passages 116 within the fixed caliper body.

[0041] Of course, the present invention has many other embodiments. Without violating the spirit and essence of the present invention, those skilled in the art may make corresponding changes and modifications based on the present invention. However, these corresponding changes and modifications should be regarded as improvements of equivalent technologies and fall within the scope of protection of the claims of the present invention.

Claims

1. A tool for cutting and bending the tail of a cotter pin, characterized by: It includes a fixed part, a movable part and a clamp shaft; the fixed part includes a fixed clamp body, a fixed shaft, a center positioning block, a positioning block and an adjusting screw; the movable part includes a movable clamp body, a connecting shaft and a conversion head; the vertical cross-section of the fixed clamp body is in the shape of "ㄣ", and the movable clamp body is a rectangular parallelepiped, and the two are connected by a clamp shaft in the middle, one end of the clamp shaft is fixed on the fixed clamp body, and the other end is rotatably fixed on the movable clamp body; steps I and II are raised on the opposite surfaces of the upper ends of the fixed clamp body and the movable clamp body, respectively, and the inner end plane I of the fixed clamp body at step I and the inner end plane of the movable clamp body at step II Ⅱ are arranged relatively; the upper ends of the fixed pliers body and the movable pliers body at the steps Ⅰ and Ⅱ are respectively provided with a through slot Ⅰ matching the positioning block and a through slot Ⅱ matching the conversion head body; the positioning block is fixed in the through slot Ⅰ of the fixed pliers body by a fixed shaft and its inner end face opposite to the workpiece nut protrudes from the inner end plane Ⅰ of the fixed pliers body; the center positioning block is dovetail-shaped with a small front end and a large rear end; the inner end face of the positioning block is provided with a step Ⅲ that fits with the lower end face of the workpiece nut, and the positioning block at the upper end of the step Ⅲ is provided with a dovetail groove that passes through the upper end face and fits with the clearance of the rear end of the center positioning block; the bottom wall of the dovetail groove is provided with a A threaded hole perpendicular to its bottom wall and matching with the adjusting screw; the rear end of the center positioning block is placed in the dovetail groove, and its front end can extend into and abut against the cotter pin fixing groove of the workpiece nut, and its rear end is provided with a threaded groove; the adjusting screw is threadedly connected to the threaded hole of the positioning block, and the front end is fixed in the threaded groove of the center positioning block; the conversion head includes a conversion head body, and the conversion head body protrudes a protrusion with an angular front end at one end relative to the workpiece nut; the front end of the protrusion is a bent inclined surface, and the plane in contact with the cotter pin is an extrusion surface, and a blade is provided on the front edge where the bent inclined surface intersects with the opposite surface of the extrusion surface. The sum of the thickness of the protrusion and the radius of the cotter pin matches the width of the cotter pin fixing groove of the workpiece nut, and a slot entry limit mechanism is provided on the protrusion; the conversion head body is detachably fixed in the through slot II of the movable pliers body by the connecting shaft, and the bent inclined surface on its protrusion is arranged parallel to the inner end face of the positioning block; when working, the positioning block of the fixed pliers body and the workpiece nut are adsorbed together, and the center positioning block is pressed against a cotter pin fixing groove of the workpiece nut but has a distance from the workpiece bolt, and the protrusion of the conversion head can squeeze one end of the cotter pin into the other opposite cotter pin fixing groove of the workpiece nut and has a distance from the workpiece bolt.

2. The split pin tail cutting and bending tool according to claim 1, characterized in that: The structure in which the positioning block of the fixed pliers body and the workpiece nut are adsorbed together is: the positioning block is a permanent magnet, and the workpiece nut is made of a material that is adsorbed by magnets; the fixed pliers body, fixed shaft, center positioning block, adjusting screw, movable pliers body, connecting shaft, conversion head and pliers shaft are made of materials that are not adsorbed by magnets.

3. The split pin tail cutting and bending tool according to claim 2, characterized in that: The movable part also includes an elastic retaining ring; one end of the connecting shaft is a square shaft and the other end is a cylindrical shaft, and a connecting shaft mounting hole with a square hole at one end and a circular hole at the other end is formed on the conversion head body, and a through square hole and a through circular hole are respectively formed on the two walls of the through slot II of the movable clamp body at positions corresponding to the connecting shaft mounting hole of the conversion head body; the conversion head body is placed in the through slot II, and is fixed on the two walls of the through slot II by the connecting shaft and the elastic retaining ring clamped on the end of the cylindrical shaft of the connecting shaft; the elastic retaining ring is made of a material that is not attracted by magnets.

4. The split pin tail cutting and bending tool according to claim 1, characterized in that: The structure in which the positioning block of the fixed pliers body and the workpiece nut are adsorbed together is: sealing gaskets are respectively fixed on the positioning block steps III on both sides of the positioning block dovetail groove, and a through ventilation channel is opened in the positioning block, and the through ventilation channel passes through the fixed pliers body to form an external ventilation port, and a pipe joint connected to the vacuum pump is fixed on the external ventilation port; ventilation holes are respectively opened on the two sealing gaskets, and the ventilation holes on the two sealing gaskets are connected to the ventilation channel in the fixed pliers body.

5. The split pin tail cutting and bending tool according to claim 4, characterized in that: The movable part also includes an elastic retaining ring; one end of the connecting shaft is a square shaft and the other end is a cylindrical shaft, and a connecting shaft mounting hole with a square hole at one end and a round hole at the other end is opened on the conversion head body, and a through square hole and a through round hole are respectively opened on the two walls of the through slot II of the movable clamp body at positions corresponding to the connecting shaft mounting hole of the conversion head body; the conversion head body is placed in the through slot II, and is fixed on the two walls of the through slot II by the connecting shaft and the elastic retaining ring clamped on the end of the cylindrical shaft of the connecting shaft.

6. The split pin tail cutting and bending tool according to claim 1, 2, 3, 4 or 5, characterized in that: The specific structure in which one end of the caliper shaft is fixed to the fixed caliper body and the other end is rotatably fixed to the movable caliper body is as follows: one end of the caliper shaft is a cylindrical shaft, and the other end is a spline shaft with one or more key protrusions; a mounting hole I that matches the spline shaft of the caliper shaft and a mounting hole II that gap-fits with the cylindrical shaft of the caliper shaft are respectively provided at the middle relative positions of the fixed caliper body and the movable caliper body; one end of the caliper shaft passes through the mounting hole I of the fixed caliper body, and the other end passes through the mounting hole II of the movable caliper body, and both ends are riveted to the fixed caliper body and the movable caliper body.

7. The split pin tail cutting and bending tool according to claim 6, characterized in that: The specific structure of the positioning block fixed in the through slot I of the fixed caliper body by the fixed shaft is: a fixing hole and a fixed through hole are respectively opened on the positioning block and the two end walls of the through slot I, and the fixed shaft is interference fitted in the fixing hole and the fixed through hole.

8. The split pin tail cutting and bending tool according to claim 7, characterized in that: The angle formed by the intersection of the bending slope of the conversion head and the opposite surface of the extrusion surface is less than 90°.

9. The split pin tail cutting and bending tool according to claim 8, characterized in that: The slot entry limiting mechanism provided on the protrusion of the conversion head is: the extrusion surface has an inclination angle of 5 to 10° relative to the plane where the side of the workpiece nut groove is located, so that the thickness of the protrusion ensures that the extruded cotter pin cannot move into the workpiece nut groove when it is in place; or the slot entry limiting mechanism provided on the protrusion of the conversion head is a gear protrusion provided on the convex extrusion surface and the surface opposite to the extrusion surface.

10. The split pin tail cutting and bending tool according to claim 1, 2, 3, 4 or 5, characterized in that: The angle between the bent inclined surface of the conversion head and the opposite surface of the extrusion surface is less than 90°; the slot entry limiting mechanism arranged on the protrusion of the conversion head is: the extrusion surface has an inclination angle of 5 to 10° relative to the plane where the side of the workpiece nut groove is located, so that the thickness of the protrusion ensures that the extruded cotter pin cannot move into the workpiece nut groove when it is in place; or the slot entry limiting mechanism arranged on the protrusion of the conversion head is a gear protrusion arranged on the convex extrusion surface and the opposite surface of the extrusion surface.

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