A thread clamping mechanism driven by a stepping motor

Abstract

The utility model discloses a kind of line clamping mechanisms of step-by-step drive, including step motor, line clamping cam, line clamping drive rod group, bottom line clamping piece and line clamping fixed block;The step motor is linked with line clamping cam, elliptical cam groove is provided on the line clamping cam;The line clamping drive rod group includes first movable link, main drive shaft and first connecting rod, one end of the first movable link is connected with a roller, the roller is slidably arranged in the cam groove, the other end of the first movable link is locked with the main drive shaft to realize linkage, first buffer assembly is arranged between the first movable link and main drive shaft, two ends of the first connecting rod are connected with bottom line clamping piece and main drive shaft respectively;The line clamping fixed block is arranged at one side of the bottom line clamping piece, and line clamping is cooperated with bottom line clamping piece. The cooperation of step-by-step and cam and optimized transmission structure can effectively improve the stability of cutting line, reduce bird nest phenomenon.

Description

Technical Field

[0001] This utility model relates to the field of sewing equipment, and in particular to a stepper-driven thread clamping mechanism. Background Technology

[0002] Sewing machines are widely used in industries such as shoemaking, handbag manufacturing, luggage making, clothing, and automotive interiors. They can sew fabrics such as cotton, linen, silk, wool, and synthetic fibers, as well as leather, plastic, and paper products. The stitches produced are neat, beautiful, flat, and strong. Sewing machines are fast and easy to use. However, when starting to sew, differences in materials or the length of the thread ends can affect the starting stitch. If the thread ends are too short, the stitch will not come off; if the thread ends are too long, they will form a "bird's nest" at the bottom of the sewing material, which affects product quality. The existing transmission structure is too complex. The transmission rod is mounted on the sewing machine base, and the excessively long transmission stroke results in insufficient force during thread cutting, affecting thread cutting and easily causing "bird's nests." Therefore, the current thread clamping mechanism needs to be improved. Utility Model Content

[0003] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a step-driven wire clamping mechanism. By using the combination of stepping and cam and optimizing the transmission structure, the stability of wire cutting can be effectively improved and the bird's nest phenomenon can be reduced.

[0004] To achieve the above objectives, this utility model provides a stepper-driven wire clamping mechanism, including a stepper motor, a wire clamping cam, a wire clamping drive rod assembly, a bottom wire clamping plate, and a wire clamping fixing block;

[0005] The stepper motor is linked to the wire clamping cam, and an elliptical cam groove is provided on the wire clamping cam.

[0006] The wire clamping drive rod assembly includes a first movable link, a main drive shaft, and a first connecting rod. One end of the first movable link is connected to a roller, which is slidably disposed in the cam groove. The other end of the first movable link is locked to the main drive shaft to achieve linkage. A first buffer assembly is provided between the first movable link and the main drive shaft. The two ends of the first link are respectively connected to the bottom wire clamping piece and the main drive shaft.

[0007] The wire clamping block is located on one side of the bottom wire clamping piece and cooperates with the bottom wire clamping piece to clamp the wire.

[0008] Furthermore, the first buffer assembly includes a first fixed connecting rod, a first buffer spring, and a second buffer spring. The first fixed connecting rod is provided with a first connecting arm, a second connecting arm, and a third connecting arm. A connecting sleeve is fixedly connected to the first connecting arm. The main drive shaft is engaged with the connecting sleeve and linked with the first fixed connecting rod. One end of the first movable connecting rod is movably connected to the connecting sleeve. The second connecting arm is adjacent to the other end of the first movable connecting rod and connected through the first buffer spring. One end of the second buffer spring is connected to the third connecting arm, and the other end of the second buffer spring is connected to the sewing machine base. This assembly ensures that the bobbin clamp always holds the top thread and also provides a buffering effect when the thread exceeds the specified range, preventing motor overload.

[0009] Furthermore, a limit groove is provided on the first movable connecting rod, and a limit screw is connected to the first fixed connecting rod. The limit screw is placed in the limit groove to limit the rotation of the first movable connecting rod. The limit groove restricts the rotation of the first movable connecting rod, preventing overload of the motor due to exceeding the limit.

[0010] Furthermore, the limiting groove is an arc-shaped groove. The curvature of the arc-shaped groove allows for precise control of the swing angle of the movable connecting rod by rotating the screw position. At the same time, the contact line between the screw and the arc-shaped groove is a continuous curve, which, compared to the point contact or short-side line contact of a straight groove, can disperse the pressure load and reduce the wear rate per unit area.

[0011] Furthermore, a first compression spring arm is provided at the connection between the first movable link and the first buffer spring, and a second compression spring arm is provided on the second connecting arm. The first and second compression spring arms are stacked opposite each other at the axial position of the first buffer spring, and the lengths of the first and second compression spring arms are the same. With the first and second compression spring arms, when the spring is compressed to its limit, the end faces of the two compression spring arms contact to form a rigid stop, preventing excessive compression of the spring that could lead to plastic deformation or breakage. This allows for a second limit when the first movable link swings, preventing excessive swing that could cause the bottom wire clamping plate to rotate too much and affect the clamping effect.

[0012] Furthermore, a main shaft bearing is fitted onto the main drive shaft, and this main shaft bearing is fixed to the sewing machine base to limit the movement of multiple main drive shafts. By fixing the main shaft bearing to the sewing machine base, the main drive shaft can only rotate, ensuring the stability of the bobbin thread clamping operation.

[0013] Furthermore, a second connecting rod is provided between the main drive shaft and the first connecting rod. One end of the second connecting rod has a first connecting hole for engaging the main drive shaft, and the other end of the second connecting rod is linked to the first connecting rod by a screw. The second connecting rod and the first connecting rod are positioned at a 90° angle. The second connecting rod and the main drive shaft are engaged through the first connecting hole to ensure concentricity of power transmission and reduce torque loss and wear caused by eccentricity. The second connecting rod is arranged perpendicularly to the first connecting rod, which can convert the rotational motion of the main drive shaft into orthogonal motion of the first connecting rod, allowing the first connecting rod to pull the bottom wire clamping piece back and forth for clamping and releasing.

[0014] Furthermore, the second link has a semi-circular curved structure. Within a limited space, the curved link can bypass obstacles, optimize the overall layout, and improve space utilization. At the same time, the geometric characteristics of the semi-circular curved structure can enhance bending resistance and provide stable force transmission to ensure the normal clamping and release of the bottom line clamping piece.

[0015] Furthermore, the thread clamping piece includes a thread clamping connection part, a thread clamping rotation hole, and a thread clamping arm. A thread clamping rotation shaft is sleeved on the thread clamping rotation hole and fixed to the sewing machine. The thread clamping arm is linked to the first connecting rod by a screw. The thread clamping arm has an arc structure and matches the outer edge shape of the thread clamping fixing block. This allows the thread clamping arm to rotate around the thread clamping rotation shaft, thus clamping the sewing thread in conjunction with the thread clamping fixing block.

[0016] Furthermore, the front end of the thread clamping block is an arc surface. This arc surface allows for a better and tighter contact with the clamping part, resulting in a better clamping effect on the thread.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. When sewing begins with the first stitch (preset, can be set for the second or third stitch, etc.), after the sewing machine needle bar reaches its lowest point and returns to the set position, the sewing machine sends a signal to drive the stepper motor to rotate the thread clamping cam clockwise. The roller inside the thread clamping linkage assembly moves within the thread clamping cam groove. As the stepper motor rotates clockwise, the roller, the first movable linkage, the main drive shaft, and the second linkage rotate counterclockwise. Simultaneously, the second linkage pulls the first linkage backward, which in turn pulls the bobbin thread clamping piece to rotate clockwise until it contacts the bobbin thread fixing block, completing the thread clamping action. The use of a stepper motor drive combined with an elliptical cam groove design enables precise digital control of the thread cutting timing and stroke; simultaneously, the elliptical cam groove effectively converts rotational motion into ideal variable-speed linear motion, significantly improving power transmission efficiency.

[0019] 2. The first movable link can rotate around the first fixed link group, and the rotation range is within the limit groove of the first movable link. When the wire is not clamped, the first movable link and the first fixed link are located at the maximum range of motion through the action of the first buffer spring. Since the limit groove is an arc-shaped structure, when the first movable link rotates, the protrusion of the limit groove will squeeze the limit screw, forcing it to drive the first fixed link to rotate as well. When the bottom wire clamping piece contacts the bottom wire fixing block, the limit screw has not yet reached the end of the limit groove. Therefore, the first movable link can still continue to rotate around the first fixed link at a certain angle. This ensures that the bottom wire clamping piece and the bottom wire fixing block can always clamp the top wire, and also provides a buffering effect when the range is exceeded, avoiding motor overload. Attached Figure Description

[0020] To more clearly illustrate the technology 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 some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a stepper-driven wire clamping mechanism according to this utility model;

[0022] Figure 2 This is a schematic diagram of the wire clamping cam of this utility model;

[0023] Figure 3 yes Figure 1 A schematic diagram of the stepper motor from another perspective, with the stepper motor hidden.

[0024] Figure 4 This is an exploded view of the clamping drive rod assembly and the first buffer assembly of this utility model;

[0025] Figure 5 This is a structural schematic diagram of the first fixed connecting rod, the connecting sleeve, and the main drive shaft of this utility model;

[0026] Figure 6 This is a structural schematic diagram of the bottom line clamping piece and the clamping fixing block of this utility model;

[0027] Figure 7 This is an assembly diagram of the present invention installed on the base of a sewing machine;

[0028] Figure 8 This is a schematic diagram of the running trajectory of the present invention when it enters the clamping state.

[0029] The diagram includes:

[0030] 1. Stepper motor; 11. Motor mounting bracket; 2. Wire clamping cam; 21. Cam groove; 22. Second connecting hole; 23. Second opening; 24. Second locking hole; 3. Wire clamping drive rod assembly; 31. First movable connecting rod; 311. First mounting part; 312. Third connecting hole; 313. Connecting shaft; 314. Fifth connecting hole; 315. Shaft retaining ring; 316. Limiting groove; 3161. Protrusion; 317. First compression spring arm; 32. Main drive shaft; 321. Second flat surface; 33. First connecting rod; 34. Main shaft bearing; 35. Second connecting rod; 351. First connecting hole; 4. Bottom wire clamping piece; 41. Wire clamping connecting part; 42. 43. Thread clamping rotating hole; 44. Thread clamping arm; 5. Thread clamping rotating shaft; 6. Thread clamping fixing block; 7. Roller; 8. First buffer assembly; 9. First fixing connecting rod; 10. First connecting arm; 11. Second connecting arm; 12. Third connecting arm; 13. Fourth connecting hole; 14. First flat inner wall; 15. Second compression spring arm; 16. First buffer spring; 17. Second buffer spring; 18. Connecting sleeve; 19. Sleeve shaft hole; 10. Sleeve connecting part; 11. Sleeve connecting protrusion; 12. First flat surface; 13. Sleeve locking hole; 14. Limiting screw; 15. Sewing machine base; 16. Needle plate. Detailed Implementation

[0031] The technology of this embodiment of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiment is one embodiment of the present invention, and not all embodiments thereof. Based on this embodiment of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0033] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second", such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0034] Please see Figures 1 to 8 The present invention provides a stepper-driven wire clamping mechanism, including a stepper motor 1, a wire clamping cam 2, a wire clamping drive rod group 3, a bottom wire clamping piece 4, and a wire clamping fixing block 5;

[0035] like Figure 1 and Figure 2 As shown, the stepper motor 1 is linked to the wire clamping cam 2, and the wire clamping cam 2 is provided with an elliptical cam groove 21; as Figure 2 As shown, a second connecting hole 22 is provided in the middle of the wire clamping cam 2, a second opening 23 is provided on one side of the second connecting hole 22, and a second locking hole 24 is provided for closing the second opening 23. During reassembly, the rotating shaft of the stepper motor 1 can be directly inserted into the second connecting hole 22, and then the second opening 23 can be locked by screws and other parts in conjunction with the second locking hole 24, thereby achieving the linkage between the stepper motor 1 and the wire clamping cam 2.

[0036] like Figure 3 and Figure 4 As shown, the wire clamping drive rod assembly 3 includes a first movable link 31, a main drive shaft 32, and a first connecting rod 33. The middle part of the first movable link 31 extends outward to form a first mounting part 311. A third connecting hole 312 is provided on the first mounting part 311. A connecting shaft 313 is connected to the third connecting hole 312. A roller 6 is connected to the end of the connecting shaft 313. The roller 6 is slidably disposed in the cam groove 21, so that when the wire clamping cam 2 rotates, it can drive the roller 6 to rotate along the cam groove 21, thereby realizing the action of the wire clamping cam 2 driving the first movable link 31 to rotate.

[0037] A first buffer assembly 7 is provided between the first movable link 31 and the main drive shaft 32. The linkage between the first movable link 31 and the main drive shaft 32 is realized through the first buffer assembly 7. Figures 3 to 5As shown, in this embodiment, the first buffer assembly 7 includes a first fixed connecting rod 71, a first buffer spring 72, and a second buffer spring 73. The first fixed connecting rod 71 is provided with a first connecting arm 711, a second connecting arm 712, and a third connecting arm 713. A connecting sleeve 74 is fixedly connected to the first connecting arm 711. The main drive shaft 32 is engaged with the connecting sleeve 74 and linked with the first fixed connecting rod 71. Specifically, a fourth connecting hole 714 is provided on the first connecting arm 711. The inner wall of the fourth connecting hole 714 is provided with a first straight inner wall 7141. The connecting sleeve 74 is provided with a sleeve shaft hole 741 that penetrates the connecting sleeve 74. A sleeve connecting part 742 is provided at the lower end of the connecting sleeve 74. The sleeve connecting part 742 is provided with a sleeve connecting protrusion 7421 that matches the fourth connecting hole 714. The sleeve connecting protrusion 7421 is provided with a first flat surface 7422 that matches the first flat inner wall 7141. During assembly, the sleeve connecting part 742 of the connecting sleeve 74 is directly inserted into the fourth connecting hole 714, so that the first flat surface 7422 and the first flat inner wall 7141 can cooperate to realize the linkage between the two. A sleeve locking hole 743 communicating with the sleeve shaft hole 741 is provided on one side of the connecting sleeve 74. The lower end of the main drive shaft 32 is inserted into the sleeve shaft hole 741, and the main drive shaft 32 is locked with the sleeve locking hole 743 by bolts and other parts. In order to increase the connection stability between the connecting sleeve 74 and the main drive shaft 32, a second flat surface 321 is provided at the lower end of the main drive shaft 32. When locking, the bolt can directly press against the second flat surface 321 to lock, thereby making the lock more secure.

[0038] Meanwhile, a fifth connecting hole 314 is provided at one end of the first movable connecting rod 31, and the sleeve connecting part 742 is directly inserted into the fifth connecting hole 314, so that the first movable connecting rod 31 can rotate around the sleeve connecting part 742 to achieve a movable connection with the connecting sleeve 74. Finally, the first movable connecting rod 31 is locked by the provided shaft retaining ring 315 to prevent the first movable connecting rod 31 from falling off.

[0039] A limiting groove 316 is provided on the first movable connecting rod 31, and a limiting screw 75 is connected to the first fixed connecting rod 71. The limiting screw 75 is placed in the limiting groove 316 to limit the first movable connecting rod 31. The limiting groove 316 is an arc groove. Through the cooperation of the limiting groove 316 and the limiting screw 75, the first movable connecting rod 31 and the first fixed connecting rod 71 are linked, thereby driving the rotation of the main drive shaft 32. Preferably, a protrusion 3161 is provided on the inner wall of one side of the limiting groove 316.

[0040] Furthermore, to further improve the buffering effect between the first movable link 31 and the first fixed link 71, and to protect the first buffer spring 72, the second connecting arm 712 is adjacent to the other end of the first movable link 31 and connected by the first buffer spring 72. A first compression spring arm 317 is provided at the connection between the first movable link 31 and the first buffer spring 72, and a second compression spring arm 715 is provided on the second connecting arm 712. The first compression spring arm 317 and the second compression spring arm 715 are stacked opposite each other at the axial position of the first buffer spring 72. Furthermore, the first spring arm 317 and the second spring arm 715 have the same length. When the first movable link 31 rotates, it compresses the first buffer spring 72, causing the first spring arm 317 and the second spring arm 715 to move relative to each other. Eventually, the first spring arm 317 and the second spring arm 715 will abut against the side of the second connecting arm 712 and the side of the first movable link 31, respectively, so that the first movable link 31 and the first fixed link 71 rotate synchronously and no longer compress the first buffer spring 72, thereby protecting the first buffer spring 72.

[0041] One end of the second buffer spring 73 is connected to the third connecting arm 713, and the other end of the second buffer spring 73 is connected to the sewing machine base 8. The second buffer spring 73 buffers the rotation of the first fixed connecting rod 71 to prevent overload and damage to parts.

[0042] A main shaft bearing 34 is fitted onto the main drive shaft 32 and is fixed to the sewing machine base 8 to limit the movement of the multiple main drive shafts 32. By fixing the main shaft bearing 34 to the sewing machine base 8, the main drive shaft 32 can only rotate, ensuring the stability of the bottom thread clamp 4 during operation.

[0043] The two ends of the first connecting rod 33 are connected to the bottom wire clamping piece 4 and the main drive shaft 32, respectively. A second connecting rod 35 is also provided between the main drive shaft 32 and the first connecting rod 33. One end of the second connecting rod 35 is provided with a first connecting hole 351 for sleeved with the main drive shaft 32. The other end of the second connecting rod 35 is linked to the first connecting rod 33 by a screw. The second connecting rod 35 and the first connecting rod 33 are distributed at 90°. Preferably, the second connecting rod 35 has a crescent-shaped bending structure. In a limited space, the bending connecting rod can bypass obstacles, optimize the overall layout, and improve the space utilization. At the same time, the geometric characteristics of the crescent-shaped bending structure can enhance the bending resistance and provide stable force transmission to ensure the normal clamping and loosening of the bottom wire clamping piece 4.

[0044] The wire clamping fixing block 5 is located on one side of the bottom wire clamping piece 4 and cooperates with the bottom wire clamping piece 4 to clamp the wire. Specifically, as follows: Figure 6As shown, the thread clamping piece 4 includes a thread clamping connection part 41, a thread clamping rotation hole 42, and a thread clamping arm 43. A thread clamping rotation shaft 44 is sleeved on the thread clamping rotation hole 42 and is fixed to the sewing machine. The thread clamping arm 43 is linked to the first connecting rod 33 by a screw. The thread clamping arm 43 has an arc structure and matches the outer edge shape of the thread clamping fixing block 5. This allows the thread clamping arm 43 to rotate around the thread clamping rotation shaft 44 as the axis, and can cooperate with the thread clamping fixing block 5 to clamp the sewing thread. The front end of the thread clamping fixing block 5 has an arc surface. The arc surface allows for better and tighter contact with the clamping part, resulting in a better clamping effect on the sewing thread.

[0045] Brief description of the working principle of this utility model: The assembly of this utility model is as follows: Figure 7 and Figure 8 As shown, the stepper motor 1 can be mounted on the side of the sewing machine base 8 via a motor mounting bracket 11. The bobbin thread clamp 4 and the bobbin thread fixing block are directly mounted below the needle plate 81 of the sewing machine base 8. The two main shaft bearings 34 at the upper and lower ends of the main drive shaft 32 are respectively snapped onto the sewing machine base 8. The other end of the second buffer spring 73 is fixedly connected to the sewing machine base 8 by screws, etc. During operation, such as Figure 8 As shown, when the sewing machine needle bar returns to the set position after the first stitch (preset, can be set to the second or third stitch, etc.) reaches its lowest point, the sewing machine sends a signal to drive the stepper motor 1 to rotate the thread clamping cam 2 clockwise. The roller 6 in the thread clamping linkage assembly moves in the groove of the thread clamping cam 2. When the stepper motor 1 rotates clockwise, the roller 6, the first movable linkage 31, the main drive shaft 32 and the second linkage 35 rotate counterclockwise. At the same time, the second linkage 35 pulls the first linkage 33 to move backward. The first linkage 33 then pulls the bottom thread clamping piece 4 to rotate clockwise until it contacts the bottom thread fixing block, completing the thread clamping action.

[0046] When the needle bar reaches the lowest point after sewing the second stitch (preset, can be set to the third or fourth stitch, etc.) and rises back to the set position, the sewing machine sends a signal again to cause the stepper motor 1 to reverse counterclockwise and return to its original position. Through the aforementioned intermediate transmission component, the bobbin thread clamp 4 rotates counterclockwise to its initial position, completing the entire operation.

[0047] A brief description of the operating principle of the first movable link 31 and the first fixed link 71: The first movable link 31 can rotate around the first fixed link 71, with the rotation range being the limit screw 75 within the limit groove 316 of the first movable link 31. When the wire is not clamped, the first movable link 31 and the first fixed link 71 are located at their maximum range of motion through the action of the first buffer spring 72. Since the limit groove 316 is an arc-shaped structure, when the first movable link 31 rotates, the protrusion 3161 of the limit groove 316 will squeeze the limit screw 75, forcing it to drive the first fixed link 71 to rotate as well. When the bottom thread clamping piece 4 contacts the bottom thread fixing block, the limit screw 75 has not yet reached the end of the limit groove 316. Therefore, the first movable link can still continue to rotate around the first fixed link 71 at a certain angle. This ensures that the bottom thread clamping piece 4 and the bottom thread fixing block can always clamp the top thread, and also provides a buffering effect when the range is exceeded, avoiding motor overload.

[0048] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A stepper-driven wire clamping mechanism, characterized in that, It includes a stepper motor (1), a wire clamping cam (2), a wire clamping drive rod assembly (3), a bottom wire clamping plate (4), and a wire clamping fixing block (5); The stepper motor (1) is linked with the wire clamping cam (2), and an elliptical cam groove (21) is provided on the wire clamping cam (2); The wire clamping drive rod assembly (3) includes a first movable link (31), a main drive shaft (32), and a first link (33). One end of the first movable link (31) is connected to a roller (6), which is slidably disposed in the cam groove (21). The other end of the first movable link (31) is locked with the main drive shaft (32) to achieve linkage. A first buffer assembly (7) is provided between the first movable link (31) and the main drive shaft (32). The two ends of the first link (33) are respectively connected to the bottom wire clamping piece (4) and the main drive shaft (32). The wire clamping fixing block (5) is disposed on one side of the bottom wire clamping piece (4) and cooperates with the bottom wire clamping piece (4) to clamp the wire.

2. The stepper-driven wire clamping mechanism according to claim 1, characterized in that, The first buffer assembly (7) includes a first fixed connecting rod (71), a first buffer spring (72), and a second buffer spring (73). The first fixed connecting rod (71) is provided with a first connecting arm (711), a second connecting arm (712), and a third connecting arm (713). A connecting sleeve (74) is fixedly connected to the first connecting arm (711). The main drive shaft (32) is engaged with the connecting sleeve (74) and linked with the first fixed connecting rod (71). One end of the first movable connecting rod (31) is movably connected to the connecting sleeve (74). The second connecting arm (712) is adjacent to the other end of the first movable connecting rod (31) and connected through the first buffer spring (72). One end of the second buffer spring (73) is connected to the third connecting arm (713), and the other end of the second buffer spring (73) is connected to the sewing machine base (8).

3. The stepper-driven wire clamping mechanism according to claim 2, characterized in that, The first movable link (31) is provided with a limiting groove (316), and the first fixed link (71) is connected to a limiting screw (75). The limiting screw (75) is placed in the limiting groove (316) to limit the first movable link (31).

4. The stepper-driven wire clamping mechanism according to claim 3, characterized in that, The limiting groove (316) is an arc groove.

5. A stepper-driven wire clamping mechanism according to claim 2, characterized in that, A first compression spring arm (317) is provided at the connection between the first movable link (31) and the first buffer spring (72), and a second compression spring arm (715) is provided on the second connecting arm (712). The first compression spring arm (317) and the second compression spring arm (715) are stacked opposite each other at the axial position of the first buffer spring (72), and the lengths of the first compression spring arm (317) and the second compression spring arm (715) are the same.

6. The stepper-driven wire clamping mechanism according to claim 1, characterized in that, A main shaft bearing (34) is fitted on the main drive shaft (32), and the main shaft bearing (34) is fixed to the sewing machine base (8) to realize the limiting of multiple main drive shafts (32).

7. A stepper-driven wire clamping mechanism according to claim 2, characterized in that, A second connecting rod (35) is also provided between the main drive shaft (32) and the first connecting rod (33). One end of the second connecting rod (35) is provided with a first connecting hole (351) for sleeved with the main drive shaft (32). The other end of the second connecting rod (35) is linked with the first connecting rod (33) by a screw. The second connecting rod (35) and the first connecting rod (33) are distributed at 90°.

8. The stepper-driven wire clamping mechanism according to claim 7, characterized in that, The second link (35) has a semi-circular curved structure.

9. A stepper-driven wire clamping mechanism according to claim 1, characterized in that, The bottom thread clamping piece (4) includes a thread clamping connection part (41), a thread clamping rotation hole (42), and a thread clamping arm (43). A thread clamping rotation shaft (44) is sleeved on the thread clamping rotation hole (42). The thread clamping rotation shaft (44) is fixed on the sewing machine. The thread clamping arm (43) is linked to the first connecting rod (33) by a screw. The thread clamping arm (43) has an arc structure and matches the outer edge shape of the thread clamping fixing block (5).

10. A stepper-driven wire clamping mechanism according to claim 1, characterized in that, The front end of the clamping block (5) is an arc surface.

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