Automatic thread cutting and thread dropping prevention mechanism for sewing machine

Abstract

The utility model discloses a sewing machine is with automatic thread cutting anti -thread shedding mechanism, include: motor, cam and frame, motor is used to control cam rotation, when cam rotates clockwise, thread cutting trigger end pulls thread cutting link piece group control thread cutting subassembly completes thread cutting action, when cam rotates anticlockwise, thread clamping trigger end pulls thread clamping link piece group control thread clamping subassembly completes thread clamping action, through the integration of single motor drive cam structure, with single power source synchronous control thread cutting and thread clamping action, replace traditional electromagnet system, and possess sewing anti -thread shedding function.

Description

Technical Field

[0001] This utility model relates to the field of sewing machine technology, specifically to an automatic thread-cutting and anti-slipping mechanism for sewing machines. Background Technology

[0002] Roller sewing machines are a general term for a type of specialized sewing equipment used in the textile industry, particularly in the sewing of thick materials such as leather, shoes, bags, and canvas. Many roller sewing machine models are currently available on the market, such as servo direct-drive roller sewing machines, three-automatic roller sewing machines, and three-step roller sewing machines, primarily used by manufacturers of shoes, bags, and car seat cushions. In the conventional shoe machine market, sewing machines typically use an automatic thread-cutting function after sewing. Traditional sewing machine thread-cutting mechanisms are driven by electromagnets. Electromagnet-driven structures have drawbacks such as large space requirements, high noise levels, and heat generation. They also have limited parameter adjustment flexibility and require high dimensional accuracy from the thread-cutting cam, leading to overly demanding assembly requirements, inaccurate adjustments, and cumbersome processes that negatively impact production efficiency.

[0003] Furthermore, traditional sewing machine thread-cutting mechanisms leave a thread end on the needle after thread cutting. In a free state, the thread end lacks tension, and the shuttle may not be able to catch the thread and form a loop when sewing begins again. This can lead to thread slippage and stray threads in the first few stitches, seriously affecting product quality and production efficiency. Utility Model Content

[0004] Therefore, in order to solve the above problems, the purpose of this utility model is to provide an automatic thread-cutting and anti-slipping mechanism for sewing machines, comprising: Electric motor; A cam, which is connected to the output end of the motor; A frame, wherein a wire clamping assembly and a wire cutting assembly are provided within the frame; The cam includes a wire-cutting trigger part and a wire-clamping trigger part. The wire-cutting trigger part is connected to the wire-cutting assembly through a wire-cutting rod assembly, and the wire-clamping trigger part is connected to the wire-clamping assembly through a wire-clamping rod assembly. The motor is used to control the rotation of the cam. When the cam rotates clockwise, the wire-cutting trigger end pulls the wire-cutting rod assembly to control the wire-cutting component to complete the wire-cutting action. When the cam rotates counterclockwise, the wire-clamping trigger end pulls the wire-clamping rod assembly to control the wire-clamping component to complete the wire-clamping action.

[0005] Preferably, the wire-cutting trigger part includes a first spiral groove, a first slider is slidably connected in the first spiral groove, the first slider is rotatably connected to the wire-cutting rod assembly, and the first slider is used to control the movement of the wire-cutting rod assembly.

[0006] Preferably, the wire cutting rod assembly includes a wire cutting swing arm, a wire cutting collar, and a wire cutting connecting rod. The two ends of the wire cutting swing arm are respectively connected to the wire cutting trigger end and the wire cutting connecting rod. The inner edge of the wire cutting collar is fixed to the wire cutting assembly, and the outer edge of the wire cutting collar is rotatably connected to the wire cutting connecting rod.

[0007] Preferably, the wire cutting assembly includes a wire cutting shaft and a wire cutting cutter. The wire cutting shaft is fixed to a wire cutting collar, and a drive gear is fixed to the upper end of the wire cutting shaft. The wire cutting cutter is rotatably connected to the frame through a cutter shaft, and a driven gear is fixed on the cutter shaft. The driving gear meshes with the driven gear.

[0008] Preferably, the wire clamping trigger part includes a second spiral groove, a second slider is slidably connected in the second spiral groove, the second slider is rotatably connected to the wire clamping rod assembly, and the second slider is used to control the movement of the wire clamping rod assembly.

[0009] Preferably, the wire clamping rod assembly includes a first wire clamping swing arm, a second wire clamping swing arm, and a wire clamping connecting rod. The two ends of the first wire clamping swing arm are respectively connected to the wire clamping trigger end and the wire clamping connecting rod, and the two ends of the second wire clamping swing arm are respectively connected to the wire clamping assembly and the wire clamping connecting rod.

[0010] Preferably, the wire clamping assembly includes a wire clamping bracket, a wire clamping plate, and a wire clamping shaft. The lower end of the wire clamping shaft is connected to the second wire clamping swing arm, the wire clamping bracket is fixed to the wire clamping shaft, and the wire clamping plate is fixed to the frame.

[0011] Preferably, the lower end of the clamping shaft is provided with a third slider, one end of the clamping arm is provided with a sliding groove, and the third slider is engaged in the sliding groove and can move within the sliding groove.

[0012] Preferably, the frame is fixed with a first limiting post and a second limiting post, the first wire clamping arm is provided with a first limiting groove that cooperates with the first limiting post, and the second wire clamping arm is provided with a second limiting groove that cooperates with the second limiting post.

[0013] Preferably, a first spring and a second spring are connected to the frame, the first spring being connected to the wire-cutting link and the second spring being connected to the wire-clamping link.

[0014] The beneficial effects of this utility model are: This invention utilizes an integrated structure with a single motor-driven cam to synchronously control the thread cutting and clamping actions with a single power source, replacing the traditional electromagnet system and providing a sewing start-up anti-slip function. In this invention, the cam's thread-releasing end and presser foot end are designed independently in layers, achieving a compact integration of mechanical transmission, significantly reducing the size of the sewing head. Replacing the electromagnet control scheme also solves the problems of high noise and overheating. Furthermore, this invention adds a thread-clamping action to the conventional sewing process. The motor-controlled thread clamping assembly clamps the free thread end after the thread cutting action, ensuring that the next sewing start-up action can accurately complete the thread hooking action, preventing thread slippage and flying thread. Attached Figure Description

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

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the hidden part of the frame of this utility model; Figure 3 This is a schematic diagram of the cam structure; Figure 4 A schematic diagram of the cam from another angle; Figure 5 This is a schematic diagram of the wire-cutting assembly. Figure 6 A structural schematic diagram of the wire-cutting assembly from another angle; Figure 7 This is a schematic diagram of the wire clamping assembly. Figure 8 A structural schematic diagram of the wire clamping assembly from another angle; Figure 9 A schematic diagram of the wire cutting assembly and the wire clamping assembly; Figure 10 This is a cross-sectional structural diagram of the present invention; Explanation of reference numerals: 1. Frame; 11. First limiting post; 12. Second limiting post; 13. First spring; 14. Second spring; 2. Motor; 21. Cam; 211. First spiral groove; 212. Second spiral groove; 213. First slider; 214. Second slider; 3. Wire cutting assembly; 31. Wire cutting shaft; 32. Wire cutting cutter; 33. Drive gear; 34. Driven gear; 4. Wire cutting rod assembly; 41. Wire cutting swing arm; 42. Wire cutting collar; 43. Wire cutting connecting rod; 5. Wire clamping assembly; 51. Wire clamping bracket; 52. Wire clamping plate; 53. Wire clamping shaft; 531. Third slider; 6. Wire clamping rod assembly; 61. Wire clamping swing arm one; 62. Wire clamping swing arm two; 621. Sliding groove; 63. Wire clamping connecting rod; 64. First limiting groove; 65. Second limiting groove.

[0017] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0019] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element 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 this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] Unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0021] Example 1: Figures 1-10This invention discloses an automatic thread-cutting and anti-slipping mechanism for a sewing machine, comprising a frame 1, a motor 2, and a sewing machine head. Both the sewing machine head and the motor 2 are mounted on the frame 1. The sewing mechanism includes a thread-cutting assembly 3 and a thread-clamping assembly 5. The output end of the motor 2 is connected to a cam 21, which controls the rotation of the cam 21. The cam 21 includes a thread-cutting trigger part and a thread-clamping trigger part. The thread-cutting trigger part is connected to the thread-cutting assembly 3 via a thread-cutting rod assembly 4, and the thread-clamping trigger part is connected to the thread-clamping assembly 5 via a thread-clamping rod assembly 6. When the motor 2 controls the cam 21 to rotate clockwise, the thread-cutting trigger part pulls the thread-cutting rod assembly 4 to control the thread-cutting assembly 3 to complete the thread-cutting action. When the motor 2 controls the cam 21 to rotate counterclockwise, the thread-clamping trigger part pulls the thread-clamping rod assembly 6 to control the thread-clamping assembly 5 to complete the thread-clamping action.

[0022] It should be noted that the wire cutting action and the wire clamping action are performed alternately. The control system controls the motor 2 to operate the cam 21 to perform the wire cutting action or the wire clamping action as required according to the set program. The two actions will not conflict with each other.

[0023] The wire-cutting trigger and the wire-clamping trigger are integrated into the cam 21 body. The wire-cutting trigger has a first spiral groove 211, and the wire-clamping trigger has a second spiral groove 212. A first slider 213 is slidably installed in the first spiral groove 211. The first slider 213 is rotatably connected to the wire-cutting rod assembly 4, which converts the rotational motion of the cam 21 into the movement of the wire-cutting rod assembly 4. Similarly, a second slider 214 is slidably installed in the second spiral groove 212. The second slider 214 is rotatably connected to the wire-clamping rod assembly 6, which converts the rotational motion of the cam 21 into the movement of the wire-clamping rod assembly 6. The first spiral groove 211 and the second spiral groove 212 both adopt the same geometric shape, specifically: both spiral grooves have a proximal end and a distal end, wherein the radial distance from the proximal end to the rotation center of the cam 21 is smaller than that from the distal end. When the cam 21 is rotated under control, the first slider 213 and the second slider 214 slide within their respective spiral grooves, and their motion trajectories cover the transition range from the near end to the far end. The displacement of the first slider 213 and the second slider 214 is further converted into the displacement of the wire-cutting rod group 4 and the wire-clamping rod group 6 through the hinged relationship between the slider and the rod group, thereby realizing independent control of the wire-cutting action and the wire-clamping action.

[0024] The thread cutting assembly 4 includes a thread cutting swing arm 41, a thread cutting collar 42, and a thread cutting connecting rod 43. The two ends of the thread cutting swing arm 41 are respectively connected to the thread cutting trigger end and the thread cutting connecting rod 43. The inner edge of the thread cutting collar 42 is fixed to the thread cutting assembly 3, and the outer edge of the thread cutting collar 42 is rotatably connected to the thread cutting connecting rod 43. The thread cutting assembly 3 includes a thread cutting shaft 31 and a thread cutting cutter 32. The lower end of the thread cutting shaft 31 is fixed to the thread cutting collar 42, and the upper end of the thread cutting shaft 31 is fixed with a drive gear 33. The thread cutting cutter 32 is rotatably connected to the frame 1 through a cutter shaft. A driven gear 34 is fixed on the cutter shaft. The drive gear meshes with the driven gear 34. When the thread cutting shaft 31 rotates, the drive gear rotates together. The drive gear drives the driven gear 34 that meshes with it to rotate. The driven gear 34 rotates together with the thread cutting cutter 32. The rotation of the thread cutting cutter 32 can cut the sewing thread.

[0025] The wire clamping rod assembly 6 includes a first wire clamping swing arm 61, a second wire clamping swing arm 62, and a wire clamping connecting rod 63. The two ends of the first wire clamping swing arm 61 are respectively connected to the wire clamping trigger end and the wire clamping connecting rod 63. The two ends of the second wire clamping swing arm 62 are respectively connected to the wire clamping assembly 5 and the wire clamping connecting rod 63. The wire clamping assembly 5 includes a wire clamping bracket 51, a wire clamping plate 52, and a wire clamping shaft 53. The lower end of the wire clamping shaft 53 is connected to the second wire clamping swing arm 62. The wire clamping bracket 51 is fixed to the wire clamping shaft 53, and the wire clamping plate 52 is fixed to the frame 1. When the wire clamping shaft 53 rotates, the wire clamping bracket 51 rotates together. After the wire clamping bracket 51 rotates, it approaches the fixedly installed wire clamping plate 52 and then clamps the free wire end.

[0026] A third slider 531 is provided at the lower end of the clamping shaft 53. The third slider 531 is misaligned with the rotation center axis of the clamping shaft 53. One end of the clamping arm 62 is provided with a sliding groove 621. The third slider 531 is engaged in the sliding groove 621 and can move within the sliding groove 621. When the clamping arm 62 rotates, it drives the third slider 531 to rotate around the rotation center of the clamping shaft 53, thereby driving the clamping shaft 53 to rotate.

[0027] It should be noted that the wire clamping shaft 53 and the wire cutting shaft 31 have a nested structure, and their mechanical movements do not interfere with each other. Specifically, the wire clamping shaft 53 is located inside the wire cutting shaft 31, and a ball bearing sliding structure is provided between them, which greatly reduces friction and ensures that the rotation of either the wire clamping shaft 53 or the wire cutting shaft 31 will not cause the other to rotate simultaneously. (See reference...) Figure 10 .

[0028] The frame 1 is fixed with a first limiting post 11 and a second limiting post 12. The first wire clamping swing arm 61 is provided with a first limiting groove 64 and cooperates with the first limiting post 11. The second wire clamping swing arm 62 is provided with a second limiting groove 65 and cooperates with the second limiting post 12. Specifically, the first limiting post 11 and the second limiting post 12 are respectively engaged in the first limiting groove 64 and the second limiting groove 65. When the first wire clamping swing arm 61 and the second wire clamping swing arm 62 rotate, they are restricted by the first limiting post 11 and the second limiting post 12 and can only swing within a specified angle range. This is to prevent the first wire clamping swing arm 61 and the second wire clamping swing arm 62 from exceeding the limited swing distance, which would cause the wire clamping bracket 51 to get too close to the wire clamping plate 52 and cause collision damage.

[0029] A first spring 13 and a second spring 14 are connected to the frame 1. The first spring 13 is connected to the wire cutting link 43, and the second spring 14 is connected to the wire clamping link 63. The first spring 13 and the second spring 14 are used to help the wire cutting assembly 3 and the wire clamping assembly 5 reset, respectively.

[0030] Workflow: After the control system issues a wire-cutting command, the motor 2 drives the cam 21 to rotate clockwise, and the wire-cutting trigger part of the cam 21 pushes the first slider 213 to move. The first slider 213 pulls the wire-cutting rod assembly 4 through a hinge connection. Specifically, the wire-cutting swing arm 41 drives the wire-cutting connecting rod 43 to move, and the wire-cutting connecting rod 43 swings in conjunction with the wire-cutting collar 42, thereby driving the wire-cutting shaft 31 to rotate. The driving gear at the upper end of the wire-cutting shaft 31 meshes with the driven gear 34, so that the wire-cutting blade 32 fixed to the blade shaft rotates synchronously to complete the wire cutting. After the wire-cutting action is completed, the first spring 13 pulls the wire-cutting connecting rod 43 to reset, ensuring that the wire-cutting assembly 3 returns to the initial position.

[0031] After the wire cutting is completed, the control system switches commands, and the motor 2 drives the cam 21 to rotate counterclockwise. The wire clamping trigger part of the cam 21 pushes the second slider 214 to move. The second slider 214 pulls the wire clamping rod assembly 6 through a hinge. Specifically, the first wire clamping arm 61 drives the wire clamping link 63 to move, and the wire clamping link 63 moves in conjunction with the second wire clamping arm 62. The second wire clamping arm 62 drives the third slider 531 to rotate through its sliding groove 621. The third slider 531 drives the wire clamping shaft 53 to rotate. The wire clamping bracket 51 fixed to the wire clamping shaft 53 swings towards the fixed wire clamping plate 52, clamping the wire end that is in a free state after the wire is cut. After the wire clamping action is completed, the second spring 14 pulls the wire clamping link 63 to reset, ensuring that the wire clamping assembly 5 returns to its initial position.

[0032] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. An automatic thread-cutting and anti-slipping mechanism for a sewing machine, characterized in that, include: Motor (2); Cam (21), which is connected to the output end of motor (2); A frame (1) is provided with a wire clamping assembly (5) and a wire cutting assembly (3). The cam (21) includes a wire-cutting trigger part and a wire-clamping trigger part. The wire-cutting trigger part is connected to the wire-cutting assembly (3) through a wire-cutting rod assembly (4), and the wire-clamping trigger part is connected to the wire-clamping assembly (5) through a wire-clamping rod assembly (6). The motor (2) is used to control the rotation of the cam (21). When the cam (21) rotates clockwise, the wire cutting trigger end pulls the wire cutting rod assembly (4) to control the wire cutting assembly (3) to complete the wire cutting action. When the cam (21) rotates counterclockwise, the wire clamping trigger end pulls the wire clamping rod assembly (6) to control the wire clamping assembly (5) to complete the wire clamping action.

2. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 1, characterized in that, The wire-cutting trigger part includes a first spiral groove (211), and a first slider (213) is slidably connected in the first spiral groove (211). The first slider (213) is rotatably connected to the wire-cutting rod assembly (4), and the first slider (213) is used to control the movement of the wire-cutting rod assembly (4).

3. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 2, characterized in that, The wire cutting rod assembly (4) includes a wire cutting swing arm (41), a wire cutting collar (42), and a wire cutting connecting rod (43). The two ends of the wire cutting swing arm (41) are respectively connected to the wire cutting trigger end and the wire cutting connecting rod (43). The inner edge of the wire cutting collar (42) is fixed to the wire cutting assembly (3), and the outer edge of the wire cutting collar (42) is rotatably connected to the wire cutting connecting rod (43).

4. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 3, characterized in that, The wire cutting assembly (3) includes a wire cutting shaft (31) and a wire cutting cutter (32). The lower end of the wire cutting shaft (31) is fixed to the wire cutting collar (42), and the upper end of the wire cutting shaft (31) is fixed with a drive gear (33). The wire cutting cutter (32) is rotatably connected to the frame (1) through a cutter shaft. A driven gear (34) is fixed on the cutter shaft, and the drive gear meshes with the driven gear (34).

5. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 1, characterized in that, The wire clamping trigger part includes a second spiral groove (212), and a second slider (214) is slidably connected in the second spiral groove (212). The second slider (214) is rotatably connected to the wire clamping rod assembly (6), and the second slider (214) is used to control the movement of the wire clamping rod assembly (6).

6. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 5, characterized in that, The wire clamping rod assembly (6) includes a first wire clamping arm (61), a second wire clamping arm (62), and a wire clamping connecting rod (63). The two ends of the first wire clamping arm (61) are respectively connected to the wire clamping trigger end and the wire clamping connecting rod (63), and the two ends of the second wire clamping arm (62) are respectively connected to the wire clamping assembly (5) and the wire clamping connecting rod (63).

7. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 6, characterized in that, The wire clamping assembly (5) includes a wire clamping bracket (51), a wire clamping plate (52), and a wire clamping shaft (53). The lower end of the wire clamping shaft (53) is connected to the second wire clamping swing arm (62). The wire clamping bracket (51) is fixed to the wire clamping shaft (53), and the wire clamping plate (52) is fixed to the frame (1).

8. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 7, characterized in that, The lower end of the clamping shaft (53) is provided with a third slider (531) eccentrically, and one end of the clamping arm (62) is provided with a sliding groove (621). The third slider (531) is engaged in the sliding groove (621) and can move in the sliding groove (621).

9. The automatic thread-cutting and anti-slipping mechanism for a sewing machine according to claim 8, characterized in that, The frame (1) is fixed with a first limiting post (11) and a second limiting post (12). The first wire clamping arm (61) is provided with a first limiting groove (64) to cooperate with the first limiting post (11). The second wire clamping arm (62) is provided with a second limiting groove (65) to cooperate with the second limiting post (12).

10. The automatic thread-cutting and anti-slipping mechanism for sewing machines according to claim 1, characterized in that, The frame (1) is connected to a first spring (13) and a second spring (14). The first spring (13) is connected to the wire cutting rod assembly (4), and the second spring (14) is connected to the wire clamping rod assembly (6).

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