A push-pull rod drive structure for a cable tie gun

Abstract

This application discloses a push-pull rod drive structure for a cable tie gun, comprising: a cable tie gun body, a grip at one end of the cable tie gun body, and a barrel at the other end of the cable tie gun body. One end of the barrel is inserted into the cable tie gun body, and a pull rod shaft is slidably disposed within the barrel. A motor is installed within the grip, and one end of the pull rod shaft is connected to the output end of the motor. A push-pull block is slidably disposed within one end of the barrel, and one end of the pull rod shaft is connected to the push-pull block. A clamping component is disposed on the push-pull block. A shearing push block is slidably disposed within the bottom of the end of the barrel with the push-pull block, and a shearing component that cooperates with the shearing push block is disposed at one end of the barrel. Using the above method, the push-pull block is driven to move by transmitting power through the pull rod shaft, and the push-pull block also drives the barrel to slide, thereby realizing the linkage of the shearing component to perform a shearing action and cut the cable tie. Compared with the multi-link structure of the prior art, the structure is simpler and the cost is lower. The tightening and shearing of the cable tie are carried out in linkage, without the need for extra operations, making the operation more convenient.

Description

Technical Field

[0001] This utility model relates to the field of cable tie gun technology, and in particular to a push-pull rod drive structure for a cable tie gun. Background Technology

[0002] A cable tie gun, also known as a cable tie tool or wire fastener, is a tool that uses mechanical principles to quickly install and tighten cable ties. After loading the cable tie into the gun, the user aims it at the item to be tied and pulls the trigger to activate the internal mechanical mechanism. This action quickly tightens and locks the cable tie onto the object, while automatically cutting off any excess cable tie. The entire process typically takes only a few seconds, greatly improving work efficiency.

[0003] Existing cable tie guns are typically driven by an electric motor. For example, Chinese Invention Publication No. CN119329820A discloses an electric cable tie gun, comprising: a housing; a cable tie fastening assembly disposed within the housing, including a fastening pawl and a fastening link for use with the cable tie, one end of the fastening link being movably connected to the fastening pawl via a torsion spring; a cutting assembly disposed within the housing, configured to cut the cable tie after it has been tightened by the cable tie fastening assembly, the cutting assembly including a blade and a cutting link; and a power transmission system disposed within the housing, including a motor and a link assembly connected to the output end of the motor, the link assembly being movably connected to the fastening link and the cutting link respectively. As can be seen from its instruction manual and accompanying drawings, the movement of the cable tie fastening assembly is driven by a motor through a linkage assembly. Although this method can achieve cable tie tightening, the linkage assembly has a complex structure, which increases the production cost of the equipment and occupies more housing space. Furthermore, the linkage assembly achieves movement through multiple links, and due to the space limitation of the housing, its movement stroke is relatively short. This results in a short movement stroke for the cable tie fastening assembly, which requires longer cable ties to be inserted during use, leading to a poor user experience.

[0004] Therefore, there is an urgent need to design a push-pull rod drive structure for a cable tie gun to solve one or more technical problems that are lacking in the existing technology. Utility Model Content

[0005] The technical solution adopted by this utility model to solve the above-mentioned technical problems is: a push-pull rod drive structure for a cable tie gun, comprising: a cable tie gun body, one end of which is provided with a grip, characterized in that the other end of which is provided with a barrel, one end of which penetrates into the cable tie gun body, the other end of which is located outside the cable tie gun body and is slidable relative to the cable tie gun body, a pull rod shaft slidably disposed inside the barrel, a motor installed inside the grip, one end of which is connected to the output end of the motor, and the barrel being located outside the cable tie gun body. A push-pull block is slidably provided inside one end of the cable tie gun body. The end of the pull rod shaft away from the motor is connected to the push-pull block. The push-pull block is provided with a clamping component for clamping the cable tie. The pull rod shaft is driven by the motor to drive the push-pull block to reciprocate within the gun barrel. A shearing push block is slidably provided inside the bottom of the end of the gun barrel where the push-pull block is located. A shearing component that cooperates with the shearing push block is provided at the end of the gun barrel away from the cable tie gun body. When the gun barrel slides relative to the cable tie gun body, the shearing component performs a shearing action through the shearing push block.

[0006] In a preferred embodiment, the clamping assembly includes: a locking block located at the top of the push-pull block, the bottom of the locking block being rotatably connected to the push-pull block, a mating ear being provided at a position corresponding to the locking block on the push-pull block, the mating ear being covered above the locking block, and a cable tie passing between the locking block and the mating ear, the locking block rotating to engage the mating ear to squeeze the cable tie.

[0007] In a preferred embodiment, the side of the locking block facing the mating ear is further provided with locking teeth that are inclined toward the direction of the cable tie gun body.

[0008] In a preferred embodiment, the locking block is further provided with a torsion spring for keeping the locking block and the mating lug in a continuous engagement state.

[0009] In a preferred embodiment, guide grooves are respectively provided on both sides of one end of the barrel outside the cable tie gun body, and guide pins are provided through the push-pull block, with both ends of the guide pins located in the guide grooves.

[0010] In a preferred embodiment, the cable tie gun body has a second travel limiter fixedly connected to one end of the barrel. The barrel passes through the second travel limiter and can slide within the second travel limiter. Two limiting protrusions are spaced apart on the barrel, and the second travel limiter is located between the two limiting protrusions.

[0011] In a preferred embodiment, the shearing assembly includes: a rotating member rotatably disposed at the end of the barrel, the rotating member having two extensions spaced at a predetermined angle, the end of the barrel having the rotating member also having a blade, the blade engaging with one of the extensions, one end of the shearing push block being limited and connected to the second stroke limiting member, the other end of the shearing push block engaging with the other extension, and when the barrel slides toward the direction of the cable tie gun body, the shearing push block drives the rotating member to rotate, and the rotating member drives the blade to rise.

[0012] In a preferred embodiment, the cable tie gun body has a mounting bracket inside one end of the grip portion. A drive gear and a driven gear are fixedly mounted in the middle of the mounting bracket. The drive gear meshes with the driven gear and is connected to the output end of the motor. A sliding bracket is also slidably mounted in the mounting bracket. The drive gear and the driven gear are located inside the sliding bracket. The two sides of the sliding bracket facing the drive gear and the driven gear are rack-shaped. The rack-shaped side of the sliding bracket meshes with the drive gear and the other rack-shaped side meshes with the driven gear. The two sides of the sliding bracket are staggered vertically.

[0013] In a preferred embodiment, one end of the sliding bracket is provided with a bent portion, the bent portion is located above the pull rod shaft, and the tail end of the pull rod shaft is provided with a boss that cooperates with the bent portion.

[0014] The beneficial effects of this utility model are: This application uses a pull rod shaft to transmit power to drive the push-pull block to move, thereby tightening the cable tie. The push-pull block also drives the gun barrel to slide, thereby achieving the linkage of the shearing component to perform the shearing action and cut the cable tie. Compared with the multi-link technology of the prior art, the structure is simpler and the cost is lower. The tightening and shearing of the cable tie are carried out in linkage, without the need for extra operations, making the operation more convenient. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the structure of the gun barrel of this utility model; Figure 3 This is an exploded view of the gun barrel of this utility model; Figure 4 This is an internal schematic diagram of the cable tie gun body of this utility model; Figure 5 This is a schematic diagram of the structure of the mounting bracket of this utility model; Figure 6 This is a schematic diagram of the structure of the sliding bracket of this utility model.

[0016] In the picture: 10. Cable tie gun body; 101. Grip; 102. Motor; 103. Mounting bracket; 104. Drive gear; 105. Driven gear; 106. Sliding bracket; 107. Bending part; 108. Second stroke limiter; 11. Barrel; 111. Guide groove; 112. Limiting protrusion; 12. Pull rod shaft; 121. Boss; 13. Push-pull block; 131. Guide slide column; 132. Mating ear; 14. Clamping assembly; 141. Locking block; 142. Torsion spring; 143. Locking tooth; 15. Shearing push block; 16. Shearing assembly; 161. Rotating part; 162. Extension; 163. Blade. Detailed Implementation

[0017] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0018] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection" and "installation" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, "connection" can be a direct connection or an indirect connection through an intermediate medium. "Fixed" means that the devices are connected to each other and their relative positional relationship remains unchanged after the connection. The directional terms mentioned in the embodiments of this utility model, such as "inner," "outer," "top," and "bottom," are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this utility model, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0019] In the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0020] In the embodiments of this application, "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0021] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. Therefore, this application is not limited to the specific embodiments disclosed below.

[0022] like Figures 1-6 As shown, this utility model provides a push-pull lever drive structure for a cable tie gun, including: a cable tie gun body 10, a grip portion 101 at one end of the cable tie gun body 10, and a barrel 11 at the other end of the cable tie gun body 10. One end of the barrel 11 is inserted into the cable tie gun body 10, and the other end of the barrel 11 is located outside the cable tie gun body 10 and can slide relative to the cable tie gun body 10. A pull rod shaft 12 is slidably provided inside the barrel 11. A motor 102 is installed inside the grip portion 101, and one end of the pull rod shaft 12 is connected to the output end of the motor 102. The barrel 11 is located inside the end of the cable tie gun body 10. A push-pull block 13 is slidably provided. The end of the pull rod shaft 12 away from the motor 102 is connected to the push-pull block 13. The push-pull block 13 is provided with a clamping assembly 14 for clamping the cable ties. The pull rod shaft 12 drives the push-pull block 13 to reciprocate within the barrel 11 through the drive of the motor 102. A shearing push block 15 is slidably provided at the bottom of the end of the barrel 11 where the push-pull block 13 is located. A shearing assembly 16 that cooperates with the shearing push block 15 is provided at the end of the barrel 11 away from the cable tie gun body 10. When the barrel 11 slides relative to the cable tie gun body 10, the shearing assembly 16 performs a shearing action through the shearing push block 15. Specifically, the cable tie gun body 10 is gun-shaped. One end of the cable tie gun body 10 is provided with a grip 101 for easy holding by the user. A barrel 11 is provided at one end of the cable tie gun body 10. One end of the barrel 11 is inserted into the cable tie gun body 10, and the barrel 11 can slide relative to the cable tie gun body 10 within a predetermined stroke. A pull rod shaft 12 is slidably provided inside the barrel 11. A motor 102 is provided in the grip 101. One end of the pull rod shaft 12 is connected to the motor. The transmission connection is 102. The pull rod shaft 12 slides inside the barrel 11 under the drive of the motor 102. A push-pull block 13 is also slidably provided at the end of the barrel 11 outside the cable tie gun body 10. The push-pull block 13 is connected to the pull rod shaft 12 and slides inside the barrel 11 under the drive of the pull rod shaft 12. A clamping component 14 is provided at the front end of the push-pull block 13. The clamping component 14 is used to clamp the cable tie, and the clamping component 14 moves under the drive of the push-pull block 13. The cable tie is tightened by the movement of the pull rod shaft 12. At the bottom of the end of the barrel 11 where the pull rod shaft 12 drives the pull rod 13 to slide backward to a predetermined distance, the pull rod 13 abuts against the inside of the barrel 11. This is the first stroke of the pull rod 13. The continued movement of the pull rod 13 during this stroke will cause the barrel 11 to slide inside the cable tie gun body 10. This is the second stroke. Since the shearing push block 15 is fixedly connected to the cable tie gun body 10 and does not move, the sliding of the barrel 11 will cause the shearing push block 15 to change its relative position. The change in relative position will cause the shearing component 16 to perform a shearing action, thereby cutting the cable tie.

[0023] Furthermore, in this embodiment, the clamping assembly 14 includes a locking block 141, which is located above the front end of the push-pull block 13, and the bottom of the locking block 141 is rotatably connected to the push-pull block 13, and can rotate relative to the push-pull block 13 within a predetermined angle. The push-pull block 13 is also provided with a mating ear 132, which is bent from the front end side of the push-pull block 13 so that it covers the top of the locking block 141. The rotation of the locking block 141 will reduce the gap between it and the mating ear 132. When the cable tie passes through the gap between the locking block 141 and the push-pull block 13, it can be squeezed and clamped by the mating between the locking block 141 and the mating ear 132, so that when the push-pull block 13 slides, the cable tie can be pulled and tightened.

[0024] Furthermore, to enhance the clamping force of the locking block 141 on the cable tie, a locking tooth 143 is provided on the upper surface of the locking block 141, which is inclined towards the direction of the cable tie gun body 10. The cable tie itself has teeth. When the cable tie passes through the gap between the locking block 141 and the mating ear 132, the locking block 141 rotates and engages with the teeth of the cable tie through the locking tooth 143, thereby fixing the cable tie. The locking tooth 143, which is inclined in a specific direction, can generate a greater restrictive force. Since the locking tooth 143 is inclined in a specific direction, when the cable tie moves along the direction of the locking tooth 143, it will not be restricted by the locking tooth 143. However, when it moves in the opposite direction, it will be stuck to prevent the cable tie from slipping out of the clamping assembly 14 under the pulling force, thus ensuring sufficient clamping force.

[0025] Furthermore, in order to enable the locking block 141 to automatically engage with the mating ear 132 to bite the cable tie, a torsion spring 142 is provided at the connection position between the locking block 141 and the push-pull block 13. The torsion spring 142 keeps the locking block 141 in an upward tilted state at all times, so that it is always engaged with the mating ear 132.

[0026] Furthermore, to prevent the push-pull block 13 from shifting when sliding inside the barrel 11, guide grooves 111 are respectively provided in the inner walls on both sides of the barrel 11. At the same time, a guide pin 131 is inserted through the push-pull block 13, with the end of the guide pin 131 located in the corresponding guide groove 111. Through the cooperation of the guide groove 111 and the guide pin 131, the push-pull block 13 is prevented from shifting inside the barrel 11. At the same time, in conjunction with the connection between the pull rod shaft 12 and the push-pull block 13, a double-point fixation is achieved to prevent the push-pull block 13 from tilting.

[0027] Furthermore, to prevent the barrel 11 from sliding excessively within the cable tie gun body 10, a second stroke limiter 108 is fixedly connected to the front end of the cable tie gun body 10. At the same time, two spaced-apart limiter protrusions 112 are provided on the barrel 11, with the second stroke limiter 108 located between the two limiter protrusions 112. Thus, whether the barrel 11 moves forward or backward, it will be stopped after a predetermined distance, restricting further movement.

[0028] Furthermore, in this embodiment, the shearing assembly 16 includes a rotating member 161, which is rotatably disposed at the front end of the barrel 11. The rotating member 161 has two extensions 162 spaced at a predetermined angle. The front end of the shearing pusher 15 has a through hole, one extension 162 is inserted into the through hole, and the other extension 162 is also fitted with a blade 163. The blade 163 also has a through-hole extension 162 inserted into the through hole. The barrel 11 is equipped with the blade 16. A groove is also provided at position 3 to limit the sliding of the blade 163 in a predetermined direction. When the barrel 11 slides, it drives the blade 163 to slide synchronously. The sliding of the barrel 11 will cause the shearing push block 15 to push the rotating member 161 to rotate through the extension 162, so that the other extension 162 drives the blade 163 to rise. When the barrel 11 returns to its original position, it drives the blade 163 to return to its original position. The cooperation between the through hole and the extension 162 allows the rotating member 161 to return to its original position without the need for the torsion spring 142, and it is linked with the barrel 11.

[0029] Furthermore, in this embodiment, a mounting bracket 103 is fixedly connected to one end of the outer casing where the grip portion 101 is located. The mounting bracket 103 has a hollow center, and a driving gear 104 and a driven gear 105 are rotatably mounted in the center of the mounting bracket 103. The driving gear 104 is fixedly connected to the output end of the drive motor 102, and the driven gear 105 meshes with the driving gear 104 for transmission. The forward rotation of the driving gear 104 drives the driven gear 105 to rotate in the reverse direction. The sliding bracket 106 has a hollow center and is disposed on the mounting bracket 103. The drive gear 104 and driven gear 105 are slidably connected to the mounting bracket 103 within the sliding bracket 106. The drive gear 104 and driven gear 105 are also located in the middle of the sliding bracket 106. Both sides of the sliding bracket 106 facing the drive gear 104 and driven gear 105 are rack-shaped. One rack-shaped side of the sliding bracket 106 meshes with the drive gear 104, and the other side meshes with the driven gear 105. When the motor 102 drives the drive gear 104 to rotate, the drive gear 104 synchronously drives the driven gear 105 to rotate. The drive gear 104 and driven gear 105 drive... The sliding bracket 106 moves forward or backward. The front end of the sliding bracket 106 has a bent portion 107, the curvature of which matches the outer side of the pull rod shaft 12. The bent portion 107 is located above the pull rod shaft 12. Simultaneously, a boss 121 is provided at the rear end of the pull rod shaft 12. When the sliding bracket 106 moves under the drive of the motor 102, the bent portion 107 reciprocates above the pull rod shaft 12. When the bent portion 107 moves backward a certain distance, it contacts the boss 121, causing the pull rod shaft 12 to move backward via the boss 121. The pull rod shaft 12 drives the push-pull block 13 to move. Since the driving gear 104 and the driven gear 105 rotate in opposite directions, and both the driving gear 104 and the driven gear 105 are located in the middle of the sliding bracket 106, in order to avoid motion conflict, in this embodiment, the two sides of the sliding bracket 106 are staggered vertically. One side meshes with the driving gear 104 and the other side meshes with the driven gear 105. By staggering the vertical arrangement, it is avoided that a single gear meshes with both sides of the sliding bracket 106 at the same time.

[0030] It should be noted that, to prevent excessive sliding of the sliding bracket 106, abutment members are provided at both ends of the sliding bracket 106. Simultaneously, limiting members are provided within the cable tie gun housing at the maximum forward and maximum backward positions of the sliding bracket 106. When the sliding bracket 106 is at its maximum position in either direction, the limiting members block it, preventing further movement. To avoid overloading the drive motor 102, existing technology can be referenced; when the current suddenly increases to a predetermined value, the drive motor 102 stops operating. In this embodiment, a spring is also provided on the pull rod shaft 12. This spring cooperates with the barrel 11 and the cable tie gun body 10. When the pull rod shaft 12 moves backward, the spring is compressed. After the motor 102 stops operating at its extreme position, the spring returns to its original position, causing the pull rod shaft 12 to return to its original position. The reset of the motor 102 will not cause the pull rod shaft 12 to move, facilitating the implementation of other functions.

[0031] In summary, this application uses a pull rod shaft to transmit power to drive the push-pull block to move, thereby tightening the cable tie. The push-pull block also causes the gun barrel to slide, enabling the shearing component to perform a shearing action and cut the cable tie. Compared with the multi-link technology of the prior art, the structure is simpler and the cost is lower. The tightening and shearing of the cable tie are carried out in conjunction, without the need for extra operations, making the operation more convenient.

[0032] This invention is not limited to the description in the specification and embodiments. Therefore, other advantages and modifications can be readily realized by those skilled in the art. Thus, without departing from the spirit and scope of the general concept as defined by the claims and their equivalents, this invention is not limited to the specific details, representative devices and illustrated examples shown and described herein.

Claims

1. A push-pull rod drive structure for a cable tie gun, comprising: A cable tie gun body, wherein one end of the cable tie gun body is provided with a grip, characterized in that the other end of the cable tie gun body is provided with a barrel, one end of the barrel is inserted into the cable tie gun body, the other end of the barrel is located outside the cable tie gun body and the barrel is slidable relative to the cable tie gun body, a pull rod shaft is slidably provided inside the barrel, a motor is installed in the grip, one end of the pull rod shaft is drivenly connected to the output end of the motor, a push-pull block is slidably provided inside the end of the barrel located outside the cable tie gun body, the end of the pull rod shaft away from the motor is connected to the push-pull block, the push-pull block is provided with a clamping component for clamping cable ties, the pull rod shaft drives the push-pull block to reciprocate within the barrel through the drive of the motor; a shearing push block is slidably provided inside the bottom of the end of the barrel with the push-pull block, and a shearing component is provided at the end of the barrel away from the cable tie gun body that cooperates with the shearing push block, when the barrel slides relative to the cable tie gun body, the shearing component performs a shearing action through the shearing push block.

2. The push-pull rod drive structure of the cable tie gun according to claim 1, characterized in that, The clamping assembly includes: a locking block, the locking block being located at the top of the push-pull block, the bottom of the locking block being rotatably connected to the push-pull block, a mating ear being provided at a position corresponding to the locking block on the push-pull block, the mating ear being covered above the locking block, and a cable tie passing through between the locking block and the mating ear, the locking block rotating to engage the mating ear to squeeze the cable tie.

3. The push-pull rod drive structure of the cable tie gun according to claim 2, characterized in that, The side of the locking block facing the mating ear is also provided with a locking tooth that is inclined toward the direction of the cable tie gun body.

4. The push-pull rod drive structure of the cable tie gun according to claim 2, characterized in that, The locking block is also provided with a torsion spring, which is used to keep the locking block and the mating lug in a continuous engagement state.

5. The push-pull rod drive structure of the cable tie gun according to claim 1, characterized in that, The barrel is provided with guide grooves on both sides of one end of the cable tie gun body, and a guide slide post is provided in the push-pull block, with both ends of the guide slide post located in the guide groove.

6. The push-pull rod drive structure of the cable tie gun according to claim 1, characterized in that, The cable tie gun body has a second travel limiter fixedly connected to one end of the gun barrel. The gun barrel passes through the second travel limiter and can slide within the second travel limiter. Two limiting protrusions are provided at intervals on the gun barrel, and the second travel limiter is located between the two limiting protrusions.

7. The push-pull rod drive structure of the cable tie gun according to claim 6, characterized in that, The shearing assembly includes: a rotating member rotatably disposed at the end of the barrel; the rotating member having two extensions spaced at a predetermined angle; the end of the barrel with the rotating member also having a blade; the blade engaging with one of the extensions; one end of the shearing push block being limited and connected to the second stroke limiting member; the other end of the shearing push block engaging with the other extension; when the barrel slides toward the direction of the cable tie gun body, the shearing push block drives the rotating member to rotate, and the rotating member drives the blade to rise.

8. The push-pull rod drive structure of the cable tie gun according to claim 1, characterized in that, The cable tie gun body has a mounting bracket inside one end of the grip portion. A drive gear and a driven gear are fixedly mounted in the middle of the mounting bracket. The drive gear meshes with the driven gear and is connected to the output end of the motor. A sliding bracket is also slidably mounted in the mounting bracket. The drive gear and the driven gear are located inside the sliding bracket. The two sides of the sliding bracket facing the drive gear and the driven gear are rack-shaped. The rack-shaped side of the sliding bracket meshes with the drive gear and the other rack-shaped side meshes with the driven gear. The two sides of the sliding bracket are staggered vertically.

9. The push-pull rod drive structure of the cable tie gun according to claim 8, characterized in that, One end of the sliding bracket is provided with a bent portion, which is located above the pull rod shaft, and the tail end of the pull rod shaft is provided with a boss that cooperates with the bent portion.

Images