Trimming cutter head structure of sewing machine

Abstract

The utility model provides a thread trimming cutter head structure of a sewing machine, and belongs to the technical field of sewing machines. The thread trimming device solves the problem of how to improve the convenience of thread trimming operation. According to the thread trimmer head structure of the sewing machine, the sewing machine comprises a bottom plate, the thread trimmer head structure comprises a thread hooking knife, a movable knife rest and a thread trimmer located on one side of the bottom plate, a strip-shaped guide groove is formed in the movable knife rest, and a limiting screw arranged in the guide groove in a penetrating mode is connected to the bottom plate. The movable knife rest can drive the thread hooking knife on the bottom plate along the guide groove to reciprocate relative to the thread trimming knife head, a protruding part is arranged on the inner wall of one side, away from one end of the thread trimming knife, of the guide groove, a concave part is arranged on the inner wall of the other side, away from one end of the thread trimming knife, of the guide groove, and the protruding part and the concave part are opposite in position. And the minimum distance between the convex part and the concave part is equal to the width of the guide groove. The thread trimming cutter head structure of the sewing machine can improve the convenience of thread trimming operation.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewing machines and relates to a thread cutting cutter disc structure of a sewing machine. Background Technique

[0002] Sewing machines are very popular fabric sewing machines in today's life. They can form stitches on the sewing material through a sewing needle cooperating with one or more sewing threads, so that one or more layers of sewing materials are interwoven or sewn together. They are indispensable machines in the fields of clothing, textiles, etc.

[0003] It is worth mentioning that after the sewing work is completed, the operator needs to cut the sewing thread through the thread cutting mechanism on the sewing machine to ensure that the sewn fabric can be taken off the sewing machine completely. For example, a modified sewing machine thread cutting device disclosed in Chinese Patent (authorized announcement number: CN207567454U) specifically includes a bottom plate, a knife bar slidably arranged on the bottom plate, a thread hooking blade for hooking the sewing thread, a thread cutting blade for cutting the sewing thread, a rotating arm for driving the knife bar to slide, and a first guide block for guiding the displacement of the knife bar. The rotating arm is hinged to the bottom plate, and the first guide block is arranged on the bottom plate; one end of the thread hooking blade is fixedly connected to the knife bar, and the end of the thread hooking blade far from the knife bar is provided with a first cutting edge part and a second cutting edge part connected to one side of the first cutting edge part in the direction of the knife bar; the knife bar is provided with a bobbin thread stretching member for stretching the bobbin thread of the sewing thread.

[0004] From the content recorded in paragraph 0025 of the attached Figure 2 specification of the comparative document, it can be seen that when the fabric is sewn, the rotating arm 15 of the thread cutting device rotates clockwise under the drive of an external force. The clockwise rotation of the rotating arm 15 drives the knife bar 12 to move along the bottom plate 1 towards the thread hooking blade 11. The knife bar 12 moves under the guidance of the first guide block 14 and drives the thread hooking blade 11 to pass through the sewing thread of the fabric. Then the rotating arm 15 rotates counterclockwise under the drive of an external force. The counterclockwise rotation of the rotating arm 15 drives the knife bar 12 to move back. The backward movement of the knife bar 12 drives the backward movement of the thread hooking blade 11. The backward movement of the thread hooking blade 11 causes the first cutting edge part 111 and the second cutting edge part 112 to hook the bobbin thread and the surface thread in the sewing thread respectively and move them to the thread cutting blade 13 for cutting.

[0005] However, the thread cutting device disclosed in the comparative document has certain drawbacks in the actual application process. Especially for the case of multiple top threads, the routing positions of some top threads are relatively outside the first cutting edge portion 111 or the second cutting edge portion 112 itself. When the thread hooking blade 11 moves back, due to the extrusion or blockage of the remaining top threads, it is very likely that these top threads with relatively outer routing positions cannot be hooked by the first cutting edge portion 111 or the second cutting edge portion 112. Therefore, the thread cutting blade 13 cannot cut the sewing thread at one time, and then the operator needs to repeatedly control the sewing machine to perform the thread cutting work, which is extremely inconvenient. Summary of the Invention

[0006] The object of the present utility model is to address the above problems existing in the prior art and propose a thread cutting tool disc structure for a sewing machine. The technical problem to be solved by the present utility model is: how to improve the convenience of the thread cutting operation.

[0007] The object of the present utility model can be achieved by the following technical solutions: A thread cutting tool disc structure for a sewing machine, the sewing machine includes a bottom plate, the thread cutting tool disc structure includes a thread hooking blade, a movable tool holder, and a thread cutting blade located on one side of the bottom plate. A strip-shaped guide groove is formed in the movable tool holder, and a limit screw passing through the guide groove is connected to the bottom plate. The movable tool holder can drive the thread hooking blade to reciprocate relative to the cutting head of the thread cutting blade on the bottom plate along the guide groove. It is characterized in that a convex portion is provided on one inner wall of the guide groove at the end far from the thread cutting blade, and a concave portion is provided on the other inner wall of the guide groove at the end far from the thread cutting blade. The convex portion and the concave portion are opposite in position, and the minimum distance between the convex portion and the concave portion is equal to the width of the guide groove.

[0008] Under the guiding action of the groove wall of the guide groove and the limit screw, the movable knife holder drives the thread hook knife to move toward the thread cutting knife, so that the blade head of the thread hook knife protrudes from the blade head of the thread cutting knife. At this time, the plurality of surface threads slide under the guidance of the outer wall of the thread hook knife and are embedded in the thread hook groove provided on the side wall of the thread hook knife (the thread hook groove is the prior art, that is, the first blade portion or the second blade portion disclosed in the comparative document), and then the movable knife holder drives the thread hook knife to move in the opposite direction and reset, and the thread hook knife pulls the plurality of surface threads toward the blade head of the thread cutting knife until the plurality of surface threads contact the blade head of the thread cutting knife, and the plurality of surface threads are cut under the cooperation of the thread hook knife and the thread cutting knife. On the basis of this structure, the thread cutting knife disc structure of the sewing machine is provided with a protruding portion on the groove wall on one side of the guide groove near the rear end, and a recessed portion opposite to the position of the protruding portion is provided on the groove wall on the other side of the guide groove near the rear end, so that after the thread hook knife moves forward a certain distance relative to the thread cutting knife, the protruding portion and the outer wall of the limit screw The thread hooking knife is pressed against the wall, and under the pressing force of the two, the limit screw enters the recessed part and at the same time the thread hooking knife swings a certain amplitude clockwise around the limit screw, thereby ensuring that the thread hooking knife can hook the thread in a larger range, thereby ensuring that all the surface threads can enter the thread hooking groove, and in the process of the movable knife holder moving in the opposite direction, since the shape of the thread hooking groove on the thread hooking knife has a good limiting effect, it can effectively prevent part of the surface threads from escaping from the thread hooking groove when the limit screw escapes from the recessed part, so that the thread hooking knife can hook all the surface threads at one time through the thread hooking groove, and cut all the surface threads at one time through the thread cutter, without the operator repeatedly controlling the sewing machine to perform the thread cutting operation, thereby ensuring the convenience of the thread cutting operation, and since the minimum spacing between the protruding part and the recessed part is equal to the width of the guide groove, thereby ensuring that when the limit screw enters the recessed part, the outer wall of the limit screw can respectively fit with the inner wall of the recessed part and the outer wall of the protruding part, thereby effectively preventing the thread hooking knife from shaking.

[0009] In the above-mentioned thread trimmer disc structure of the sewing machine, the inner wall contour of the concave part and the outer wall contour of the convex part are both arc-shaped, ensuring that the limit screw can completely fit with the inner wall of the concave part when entering the concave part, ensuring that the thread hooking knife can stably maintain the current posture, and the outer wall surface of the convex part is more gentle, which can avoid excessive concentration of the force between the convex part and the outer wall of the limit screw as much as possible, so as to achieve the purpose of reducing wear and effectively improve the service life of the movable frame and the limit screw.

[0010] In the thread trimmer disc structure of the sewing machine, a swing link is hinged on the plate surface of the base plate, a connecting groove is provided on the movable knife holder, and one end of the swing link is embedded and limited in the connecting groove. Specifically, the present application is to connect the driving member (i.e., driving motor) with one end of the swing link hinged on the base plate through the connecting rod assembly, and the other end is embedded in the connecting groove provided on the movable knife holder and limited by the connecting groove wall, so that the driving member can drive the thread hooking knife to swing clockwise or counterclockwise by the movable knife rod when working. At this time, the thread hooking knife itself has a movable swinging amplitude, and under the cooperation of the limit screw, the protrusion in the guide groove and the recessed part in the guide groove, the hooking range of the thread hooking knife can be further expanded, thereby ensuring that the thread hooking knife can hook all the surface threads at one time and then cut them together through the thread trimmer, thereby ensuring the convenience of the thread trimming operation.

[0011] In the above-mentioned thread trimmer disc structure of the sewing machine, the thread trimmer disc structure also includes a slider, a slide rail slidably connected to the slider, and a fixed plate located on one side of the bottom plate and hinged to the bottom plate. The thread trimmer and the slider are both screwed to the fixed plate by screws, the movable knife holder is screwed to one end of the slide rail by screws, and the thread hook knife is screwed to the other end of the slide rail by screws. The slide rail is used to cooperate with the slider to ensure that the movable knife holder drives the thread hook knife to move through the slide rail, and the moving path of the slider and the slide rail is limited and guided to ensure that the moving path of the thread hook knife will never deviate.

[0012] In the above-mentioned thread trimmer disc structure of the sewing machine, the fixed plate includes a connecting portion in the shape of a rectangular plate with a connecting protrusion on one side and a long strip-shaped mounting portion, the connecting protrusion is hinged to the bottom plate through a connecting piece, and the thread trimmer is screwed to the mounting portion by a screw. Ensure that the fixed plate can swing synchronously with the movable knife holder, and the thread trimmer and the thread hook knife can maintain synchronous movement, avoid the position offset between the two that makes the thread trimming work impossible, and prevent the slide rail and the slider from getting stuck due to the change of the movable knife holder posture.

[0013] In the above-mentioned thread trimmer disc structure of the sewing machine, one side of the bottom plate has a receiving groove, and the connecting part is located in the receiving groove, thereby ensuring the freedom of movement of the connecting part and even the entire fixing plate, and avoiding interference between the connecting part and the bottom plate.

[0014] Compared with the prior art, the thread trimmer disc structure of the sewing machine has the following advantages:

[0015] When the thread hooking knife is driven by the movable tool rest to move forward relative to the thread cutting knife, the limit screw can push against the protruding part and embed into the recessed part, enabling the thread hooking knife to deflect at a certain angle, so as to ensure a larger range for the thread hooking knife to hook the thread, and further ensure that the thread hooking knife can hook all the upper threads at one time and cut them together with the thread cutting knife, ensuring the convenience of the thread cutting operation. Brief Description of the Drawings

[0016] Figure 1 is a schematic structural view of the thread cutting knife disc structure of this sewing machine.

[0017] Figure 2 is a schematic structural view of the thread cutting knife disc structure of this sewing machine from another perspective.

[0018] Figure 3 is a sectional view of the thread cutting knife disc structure of this sewing machine taken along the sliding direction of the slide rail and its partial enlarged view.

[0019] Figure 4 is a schematic structural view of the bottom plate.

[0020] Figure 5 is a schematic structural view of the movable tool rest.

[0021] Figure 6 is a schematic structural view of the fixed plate.

[0022] In the figure, 1 is the bottom plate; 11 is the swing link; 12 is the receiving groove; 2 is the movable tool rest; 21 is the guide groove; 211 is the protruding part; 212 is the recessed part; 22 is the limit screw; 23 is the connecting groove; 3 is the thread hooking knife; 4 is the thread cutting knife; 5 is the slider; 6 is the slide rail; 7 is the fixed plate; 71 is the connecting part; 711 is the connecting convex block; 72 is the mounting part; 8 is the connecting piece. Detailed Description of the Embodiment

[0023] The following are specific embodiments of the present invention in combination with the drawings, and the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments.

[0024] As Figure 1 shown in Figure 2 In the thread cutting knife disc structure of this sewing machine, the sewing machine includes a driving motor installed in the housing and a bottom plate 1 horizontally arranged on the processing tabletop. A long swing link 11 is hinged on the bottom plate 1. Specifically, the swing link 11 is hinged to the bottom plate 1 at its middle part through a pin, and one end of it is rotationally connected to the driving shaft of the driving motor through a connecting rod assembly.

[0025] The thread cutting knife disc structure includes a movable tool rest 2 and a fixed plate 7. Combining Figure 4 , a receiving groove 12 is formed on one side of the bottom plate 1. Combining Figure 6, the fixing plate 7 specifically includes a connecting portion 71 in the shape of a rectangular plate and a mounting portion 72 in the shape of a long strip. The connecting portion 71 is located in the receiving groove 12 and has a connecting bump 711 on one side wall. The connecting bump 711 on the connecting portion 71 and the fixing plate 7 are specifically hinged through a connecting piece 8. Combined with Figure 3 , the connecting piece 8 is in the shape of a long strip plate. A clamping groove is formed at one end of one side plate surface of the connecting piece 8. The connecting piece 8 is clamped with the connecting bump 711 through the clamping groove and the two are hinged through a pin. The other end of the side plate surface of the connecting piece 8 is hinged to the bottom plate 1 through a pin.

[0026] A slider 5 is screwed and locked on the connecting portion 71. A slide rail 6 is slidably connected to the slider 5. One end of the slide rail 6 is screwed and locked with the movable tool holder 2 through a screw, and a thread-cutting knife 3 is screwed and locked at the other end through a screw. A thread-cutting knife 4 is screwed and locked on the mounting portion 72 of the fixing plate 7, and the side wall of the thread-cutting knife 4 is arranged in contact with the side wall of the thread-cutting knife 3.

[0027] Combined with Figure 5 , a connecting groove 23 is formed on one side of the movable tool holder 2. The other end of the swing link 11 is embedded and limited in the connecting groove 23. In addition, a long strip-shaped guiding groove 21 is formed on the movable tool holder 2 along the sliding direction of the slide rail 6. A limit screw 22 passing through the guiding groove 21 is screwed on the bottom plate 1. The outer side wall of the limit screw 22 is in contact with the two side walls of the guiding groove 21. The end of the guiding groove 21 facing the slide rail 6 is the front end, and the end facing away from the slide rail 6 is the rear end. A protruding portion 211 is formed on one side wall of the guiding groove 21 near the rear end, and a recessed portion 212 is formed on the other side wall of the guiding groove 21 near the rear end. The positions of the protruding portion 211 and the recessed portion 212 are arranged opposite to each other, and the minimum linear distance between the two is equal to the width of the guiding groove 21.

[0028] Working principle: the driving motor starts to drive the swing connecting rod 11 to swing clockwise through the connecting rod assembly, so that the movable knife holder 2 drives the wire hook knife 3 to extend forward relative to the wire cutting knife 4. At the same time, the movable knife holder 2 drives the wire hook knife 3 to swing clockwise. At the same time, since the fixed plate 7 and the bottom plate 1 are hinged by the connecting piece 8, and since the movable knife holder 2 and the fixed plate 7 are connected by the slide rail 6 and the slider 5, the wire cutting knife 4 on the fixed plate 7 can swing synchronously with the wire hook knife 3. In this process, when the movable knife holder 2 is displaced to make the limit screw 22 conflict with the protrusion 211, the conflict force generated between the two can make the limit screw 22 embedded in the recessed portion 212 and contact the outer wall of the protrusion 211. The movable knife holder 2 is fitted, and the swing amplitude of the movable knife holder 2 is further enlarged at this time, and the swing amplitude of the thread hooking knife 3 is also further enlarged. In the current state, the thread hooking range of the thread hooking knife 3 is ensured to be wider, so that a number of surface threads are all embedded in the thread hooking groove opened on the outer wall of the thread hooking knife 3 under the guiding action of the outer wall of the thread hooking knife 3, and then the driving motor is started and the driving shaft is reversed, so that the movable knife holder 2 drives the thread hooking knife 3 to swing and reset. Since the shape of the thread hooking groove itself has a good limiting effect, a number of surface threads that have been embedded in the thread hooking groove will no longer fall out of the thread hooking groove, until the knife head of the movable thread hooking knife 3 continues to approach the knife head of the thread cutting knife 4 so that a number of surface threads contact the knife head of the thread cutting knife 4, and under the shearing force, a number of surface threads are cut together by the knife head of the thread cutting knife 4.

[0029] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0030] Although the terminology such as bottom plate 1, swing link 11, receiving slot 12, movable knife holder 2, guide slot 21, protrusion 211, recess 212, stop screw 22, connection slot 23, thread hooking knife 3, thread cutting knife 4, slider 5, slide rail 6, fixing plate 7, connection portion 71, connection protrusion 711, mounting portion 72, connection sheet 8 is used more frequently in this article, the possibility of using other terms is not excluded. The use of these terms is only for more convenient description and explanation of the essence of the utility model; interpreting them as any additional restrictions is contrary to the spirit of the utility model.

Claims

1. A thread trimmer disc structure of a sewing machine, the sewing machine comprising a bottom plate (1), the thread trimmer disc structure comprising a thread hooking knife (3), a movable knife holder (2) and a thread trimmer (4) located on one side of the bottom plate (1), the movable knife holder (2) being provided with a strip-shaped guide groove (21), the bottom plate (1) being connected with a limit screw (22) penetrating the guide groove (21), the movable knife holder (2) being able to drive the thread hooking knife (3) to reciprocate relative to the knife head of the thread trimmer (4) along the guide groove (21) on the bottom plate (1), and characterized in that: The inner wall of the guide groove (21) on one side away from the end of the thread cutter (4) has a protruding portion (211), and the inner wall of the guide groove (21) on the other side away from the end of the thread cutter (4) has a concave portion (212), the protruding portion (211) and the concave portion (212) are opposite to each other, and the minimum distance between the protruding portion (211) and the concave portion (212) is equal to the width of the guide groove (21).

2. The thread trimmer disc structure of a sewing machine according to claim 1, characterized in that: The inner wall profile of the concave portion (212) and the outer wall profile of the convex portion (211) are both arc-shaped.

3. The thread trimmer disc structure of a sewing machine according to claim 1 or 2, characterized in that: A swing link (11) is hinged on the plate surface of the bottom plate (1), a connecting groove (23) is provided on the movable tool holder (2), and one end of the swing link (11) is embedded and limited in the connecting groove (23).

4. The thread trimmer disc structure of a sewing machine according to claim 3, characterized in that: The thread cutting knife disc structure also includes a slider (5), a slide rail (6) slidably connected to the slider (5), and a fixed plate (7) located on one side of the base plate (1) and hinged to the base plate (1); the thread cutting knife (4) and the slider (5) are both screwed to the fixed plate (7) by screws, the movable knife holder (2) is screwed to one end of the slide rail (6) by screws, and the thread hooking knife (3) is screwed to the other end of the slide rail (6) by screws.

5. The thread trimmer disc structure of a sewing machine according to claim 4, characterized in that: The fixing plate (7) comprises a connecting portion (71) in the shape of a rectangular plate and having a connecting protrusion (711) on one side, and a mounting portion (72) in the shape of a long strip, the connecting protrusion (711) being hingedly connected to the bottom plate (1) via a connecting piece (8), and the wire cutter (4) being screwed onto the mounting portion (72) via screws.

6. The thread trimmer disc structure of a sewing machine according to claim 5, characterized in that: One side of the bottom plate (1) has a receiving groove (12), and the connecting portion (71) is located in the receiving groove (12).

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