Bird nest prevention blade structure for a template sewing machine

Abstract

The utility model discloses a kind of bird-nest-preventing blade structures for template sewing machine, including moving knife, fixed knife, line pressing plate, moving knife includes body, knife edge, be provided with moving knife blade, moving knife line hole, moving knife wire guide, moving knife line hook on knife edge, be provided with fixed knife blade on fixed knife;Moving knife is positioned in the process of moving first on its upper surface to guide thread, then continue to move lower surface and cooperate line pressing plate to compress thread, moving knife cooperates with shearing work along with the whole process of sewing.The utility model realizes the integration of three major functions of moving knife hole distribution, line shearing guide and line shearing by the design of moving knife, reduces the number of parts of device, reduces assembly error, simultaneously make the path of thread from distribution to line shearing shorter and more stable, effectively avoid the decline of line shearing precision caused by thread deviation, further strengthen the anti "bird-nest" performance, simultaneously do not affect sewing efficiency.

Description

Technical Field

[0001] This utility model relates to the technical field of sewing machines, specifically to an anti-bird nest blade structure for template sewing machines. Background Technology

[0002] Template sewing machines are devices that achieve standardized sewing based on preset templates and are widely used in mass production scenarios such as clothing and bags. Their core advantage lies in ensuring sewing precision through template positioning; however, the shortcomings of existing thread-cutting devices directly affect the quality of the final product.

[0003] Existing thread-cutting devices on template sewing machines generally suffer from low thread-cutting accuracy and excessively long thread ends. During the initial sewing stage, the free thread remaining on the needle lacks effective restraint and is easily caught in the fabric underside by the rotary hook. Subsequent sewing actions will stitch this loose thread into the fabric, ultimately forming a bird's nest-like stitch, known in the industry as a "bird's nest." This "bird's nest" not only severely damages the smoothness and aesthetics of the sewn surface but can also cause localized fabric thickening, affecting subsequent processes (such as ironing and splicing), increasing rework rates and production costs.

[0004] Analysis revealed that the root cause of the "bird's nest" pattern lies in the excessively long thread ends remaining after thread trimming. These excessively long threads leave the thread in a free, unrestrained state when starting the stitch, resulting in excess thread exceeding a reasonable range. This excess thread is then caught in the rotary hook and forms a clump. Currently, most mainstream thread trimming devices employ traditional cam drives or dual-motor independent drive structures: the former suffers from transmission gaps, making precise control of the trimming position difficult; the latter requires complex algorithms to coordinate the movement of the two motors, which is prone to misalignment due to parameter deviations. Neither can reliably and effectively solve the problem of excessively long thread ends. Therefore, there is an urgent need for a flat-blade thread trimming device that can improve trimming accuracy and shorten residual thread ends to meet the demands of template sewing machines for efficient and high-quality sewing. Summary of the Invention

[0005] The purpose of this invention is to solve the problems mentioned in the background art and to provide an anti-bird nest blade structure for template sewing machines.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows: a bird's nest prevention blade structure for a template sewing machine, comprising a moving blade, a fixed blade, and a pressure plate. The moving blade includes a body and a blade edge, and the blade edge is provided with a moving blade edge, a moving blade thread hole, a moving blade guide opening, and a moving blade hook opening. The fixed blade is provided with a fixed blade edge. The pressure plate is fixed on the sewing machine and located on one side of the moving blade. The moving blade is connected to the power device in the sewing machine. The sewing thread passes through the moving blade thread hole along with the sewing machine needle. The needle resets, leaving the thread end in the moving blade thread hole. The power device in the sewing machine drives the moving blade to move, and the movement of the moving blade achieves the pressing and releasing of the sewing thread. During the movement, the upper surface of the moving blade first positions and guides the sewing thread, and then the lower surface continues to move to cooperate with the pressure plate to press the sewing thread. The moving blade works in conjunction with the cutting operation throughout the sewing process.

[0007] In the above-mentioned anti-bird nest blade structure for a template sewing machine, the upper surface of the moving blade is provided with a thread guide groove, one end of which is connected to the thread hole of the moving blade, and the other end extends towards the blade edge of the moving blade.

[0008] In the above-mentioned anti-bird nest blade structure for a template sewing machine, the width of the guide groove is adapted to the diameter of the sewing thread, and the groove wall is a smooth arc surface, which is used to guide the sewing thread to move along the guide groove without deviating.

[0009] In the above-mentioned anti-bird's nest blade structure for a template sewing machine, after sewing is completed, the moving blade is driven to reverse and hook the bottom thread of the sewing thread into the moving blade hooking port and the moving blade guide port respectively. As the moving blade continues to rotate forward, it is cut by the engagement of the moving blade edge and the fixed blade edge.

[0010] In the above-mentioned anti-bird's nest blade structure for a template sewing machine, the outer surface of the moving blade is provided with an arc-shaped guide surface. When the sewing action enters the preset end stage, the arc-shaped guide surface first contacts the sewing thread as the moving blade moves. Through the smooth transition of the arc-shaped guide surface, the sewing thread is guided to move along the arc-shaped trajectory towards the moving blade guide opening until the sewing thread completely enters the biting area between the moving blade and the fixed blade, thereby achieving precise cutting guidance of the sewing thread.

[0011] In the above-mentioned anti-bird's nest blade structure for a template sewing machine, the radius of curvature of the arc-shaped guide surface is matched with the bending adaptability of the sewing thread.

[0012] In the above-mentioned anti-bird nest blade structure for a template sewing machine, a thread guide surface is provided on one side of the moving blade hook opening, and the thread guide surface guides the sewing thread to be hooked into the moving blade hook opening in a specific direction.

[0013] In the above-mentioned anti-bird's nest blade structure for a template sewing machine, the pressure plate is an elastic metal sheet. One end of the pressure plate extends to the lower side of the moving blade and can press against the thread hole of the moving blade. An elastic pressing and anti-slip structure is provided on the side where the pressure plate presses against the sewing thread.

[0014] In the above-mentioned anti-bird nest blade structure for a template sewing machine, the end of the lead groove is provided with an arc-shaped transition section.

[0015] This utility model has the following beneficial effects: The flat-blade thread-cutting device of this utility model for template sewing machines integrates three major functions—thread separation, thread-cutting guidance, and thread-cutting—through the design of the moving blade. This reduces the number of parts in the device, lowers assembly errors, and makes the path of the sewing thread from separation to cutting shorter and more stable, effectively avoiding the decrease in thread-cutting accuracy caused by thread deviation.

[0016] Enhanced anti-"bird's nest" effect: The separating function of the moving blade hole ensures precise thread positioning, the pressure plate stably tightens the thread, and the thread guide structure on the moving blade ensures the thread remains constrained before cutting, preventing loose excess thread. The precise thread cutting by the blade leaves extremely short residual thread ends, fundamentally solving the problem of "bird's nest" formation. Furthermore, the design of two thread cuts during sewing ensures both the stability of the stitches during the process and the shortening effect of the thread ends at the end, further enhancing the anti-"bird's nest" performance without affecting sewing efficiency. Attached Figure Description

[0017] Figure 1 This is a perspective view of the present invention; Figure 2 This is an exploded view of the present invention; Figure 3 This is a schematic diagram of the cooperation between the moving blade, the pressure plate, and the fixed blade in this utility model; Figure 4 This is a schematic diagram of the cooperation between the moving blade and the pressure plate in this utility model. Detailed Implementation

[0018] The present invention will be further described in conjunction with the accompanying drawings.

[0019] Please see Figures 1 to 4This utility model provides an anti-bird's nest blade structure for a template sewing machine, including a moving blade 1, a fixed blade 2, and a pressure plate 3. The moving blade includes a body 4 and a blade edge 5. The blade edge 5 is provided with a moving blade edge 6, a moving blade thread hole 7, a moving blade guide opening 8, and a moving blade hook opening 9. The fixed blade 2 is provided with a fixed blade edge 10. The pressure plate 3 is fixed on the sewing machine and located on one side of the moving blade 1. The moving blade 1 is connected to the power unit in the sewing machine. The sewing thread passes through the moving blade thread hole 7 with the sewing machine needle. The needle returns to its original position, leaving the thread end in the moving blade thread hole 7. The power unit in the sewing machine drives the moving blade 1 to move. With the movement of the moving blade 1, the sewing thread is pressed and released. During the movement, the upper surface of the moving blade 1 first positions and guides the sewing thread, and then the lower surface continues to move to cooperate with the pressure plate 3 to press the sewing thread. The moving blade 1 works to cut the thread throughout the sewing process.

[0020] Furthermore, the upper surface of the moving blade 1 is provided with a lead wire groove 11, one end of which is connected to the moving blade wire hole 7, and the other end extends toward the moving blade cutting edge 6.

[0021] Furthermore, the width of the lead groove 11 is adapted to the diameter of the suture, and the groove wall is a smooth arc surface, which is used to guide the suture to move along the lead groove 11 without deviating.

[0022] Furthermore, after sewing is completed, the moving blade 1 is driven to reverse and hook the bottom thread of the sewing thread into the moving blade hooking port 9 and the moving blade guide port 8 respectively. As the moving blade 1 continues to rotate forward, it is cut by the engagement of the moving blade edge 6 and the fixed blade edge 10.

[0023] Furthermore, the outer surface of the moving blade 1 is provided with an arc-shaped guide surface 12. When the sewing action enters the preset end stage, the arc-shaped guide surface 12 moves with the moving blade 1 and first contacts the sewing thread. The smooth transition of the arc-shaped guide surface 12 guides the sewing thread to move along the arc trajectory towards the moving blade guide opening 8 until the sewing thread completely enters the biting area between the moving blade edge 6 and the fixed blade edge 10, thereby achieving precise cutting guidance of the sewing thread.

[0024] Furthermore, the radius of curvature of the arc-shaped guide surface 12 is matched with the bending adaptability of the stitch.

[0025] Furthermore, a thread guide surface 13 is provided on one side of the moving knife thread hooking opening 9, and the thread guide surface 13 guides the sewing thread to be hooked into the moving knife thread hooking opening 9 in an oriented manner.

[0026] Furthermore, the pressure plate 3 is an elastic metal sheet. One end of the pressure plate 3 extends to the lower side of the moving knife 1 and can be pressed against the moving knife thread hole 7. An elastic pressing and anti-slip structure is provided on the side where the pressure plate is pressed against the sewing thread.

[0027] Furthermore, the end of the lead groove 11 is provided with an arc-shaped transition section 11-1.

[0028] The principle of this utility model will be further explained below: Initial thread separation stage: After the template sewing machine is started, the needle 15 moves downward and passes through the moving thread hole 7. The thread 16 passes through the moving thread hole 7 with the needle 15 and is stably separated by the moving thread hole 7. Part of the thread 16 remains in the moving thread hole 7 to prepare for subsequent pressing.

[0029] Thread guiding stage: After the needle 15 completes hooking the thread and returns to its original position, the power unit in the sewing machine drives the moving blade 1 to swing slightly. The thread guide groove 11 on the moving blade 1 moves accordingly, allowing the thread 16 remaining in the thread hole 7 of the moving blade to fall naturally into the thread guide groove 11. The thread 16 moves along the smooth wall of the thread guide groove 11 towards the edge of the moving blade 6 until the end of the thread 16 reaches the arc-shaped transition section 11-1 of the thread guide groove 11. The moving blade 1 then pauses its swing to ensure that the position of the thread 16 is stable and does not deviate.

[0030] Pressing stage: After the thread 16 is guided, the power unit in the sewing machine drives the moving blade 1 to continue swinging, so that the presser plate 3 contacts the lower surface of the moving blade 1 until the presser plate 3 is in close contact with the thread 16, pressing the thread 16 tightly (the pressing force is controlled at 5-8N by the elasticity of the spring steel sheet), so as to prevent the thread 16 from loosening or shifting in subsequent sewing.

[0031] Sewing transition and initial thread trimming stage: After the pressing is completed, the needle 15 continues to sew two stitches, and the thread 16 forms a fixed stitch with the bobbin thread of the rotary hook; as the power unit in the sewing machine drives the moving blade 1 to continue rotating and swinging, the moving blade 1 moves towards the fixed blade 2, and the thread 16 moves steadily along the thread guide groove 11 until the moving blade edge 6 and the fixed blade edge 10 are fully engaged, cutting off the excess thread 16. After the initial thread 16 is cut, the sewing action is not interrupted, and the needle 15 continues to sew according to the preset sewing trajectory.

[0032] Continuous sewing and secondary thread trimming stage: When the entire sewing action reaches the preset end point, the main control system sends a command to the power unit in the sewing machine, driving the moving blade 1 to reverse its movement. At this time, the moving blade 1 moves outward at the reverse arc guide surface 12, driving the thread guide surface 13 of the moving blade 1 to hook the bottom edge of the thread 16 into the moving blade hooking opening 9 and the moving blade guide opening 8 respectively. The outer arc surface of the moving blade 1 contacts the thread 16 first, and through the guiding action of the arc guide surface 12, guides the thread 16 smoothly into the moving blade guide opening 8 along the arc trajectory of the moving blade 1. After the thread 16 has completely entered the moving blade guide opening 8, the power unit in the sewing machine drives the moving blade 1 to swing towards the fixed blade 2, so that the moving blade edge 6 and the fixed blade edge 10 precisely engage, realizing the secondary thread trimming action. At this point, the entire sewing process and thread trimming operation are completed, and the device returns to the initial state, waiting for the next cycle.

[0033] The above provides a detailed description of an anti-bird's nest blade structure for a template sewing machine provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the technical solution disclosed in the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A bird's nest prevention blade structure for a template sewing machine, comprising a moving blade (1), a fixed blade (2), and a pressure plate (3), characterized in that: The moving knife (1) includes a body (4) and a blade (5). The blade (5) is provided with a moving knife blade (6), a moving knife thread hole (7), a moving knife guide hole (8), and a moving knife hook hole (9). The fixed knife (2) is provided with a fixed knife blade (10). The pressure plate (3) is fixed on the sewing machine and located on one side of the moving knife (1). The moving knife (1) is connected to the power device in the sewing machine. The sewing thread (16) passes through the moving knife thread hole (7) along with the sewing machine needle (15). The needle resets and leaves the sewing thread end in the moving knife thread hole (7). The power device in the sewing machine drives the moving knife (1) to move. With the movement of the moving knife (1), the sewing thread is pressed and released. During the movement, the upper surface of the moving knife (1) first positions and guides the sewing thread, and then the lower surface continues to move to cooperate with the pressure plate (3) to press the sewing thread. The moving knife (1) works with the cutting operation throughout the sewing process.

2. The anti-bird nest blade structure for a template sewing machine according to claim 1, characterized in that: The upper surface of the moving blade (1) is provided with a lead wire groove (11), one end of which is connected to the moving blade wire hole (7), and the other end extends toward the moving blade cutting edge (6).

3. The anti-bird nest blade structure for a template sewing machine according to claim 2, characterized in that: The width of the guide groove (11) is adapted to the diameter of the suture, and the groove wall is a smooth arc surface, which is used to guide the suture to move along the guide groove (11) without deviating.

4. The anti-bird nest blade structure for a template sewing machine according to claim 1, characterized in that: After sewing is completed, the moving blade (1) is driven to reverse and hook the bottom thread of the sewing thread into the moving blade hooking port (9) and the moving blade guide port (8) respectively. As the moving blade (1) continues to rotate forward, it is cut by the engagement of the moving blade edge (6) and the fixed blade edge (10).

5. The anti-bird nest blade structure for a template sewing machine according to claim 4, characterized in that: The outer surface of the moving blade (1) is provided with an arc-shaped guide surface (12). When the sewing action enters the preset end stage, the arc-shaped guide surface (12) moves with the moving blade (1) and first contacts the sewing thread. Through the smooth transition of the arc-shaped guide surface (12), the sewing thread is guided to move along the arc trajectory towards the moving blade guide opening (8) until the sewing thread completely enters the biting area between the moving blade edge (6) and the fixed blade edge (10), thereby achieving precise cutting guidance of the sewing thread.

6. The anti-bird nest blade structure for a template sewing machine according to claim 5, characterized in that: The radius of curvature of the arc-shaped guide surface (12) is matched with the bending adaptability of the suture.

7. The anti-bird nest blade structure for a template sewing machine according to claim 4, characterized in that: A thread guide surface (13) is provided on one side of the moving knife hook opening (9), and the thread guide surface (13) guides the suture thread to be hooked into the moving knife hook opening (9).

8. The anti-bird nest blade structure for a template sewing machine according to claim 1, characterized in that: The pressure plate (3) is an elastic metal sheet. One end of the pressure plate (3) extends to the lower side of the moving knife (1) and can be pressed against the moving knife thread hole (7). An elastic pressing and anti-slip structure is provided on the side where the pressure plate is pressed against the sewing thread.

9. The anti-bird nest blade structure for a template sewing machine according to claim 3, characterized in that: The end of the lead groove (11) is provided with an arc-shaped transition section (11-1).

Images