Zigzag sewing machine with thread trimming structure and automatic thread trimming and presser foot lifting

Abstract

The present invention relates to the technical field of sewing machines, and in particular, to a thread trimming structure and a zigzag sewing machine with automatic thread trimming and presser foot lifting, comprising a stepping motor assembly and a cam mechanism, wherein the cam mechanism is driven to rotate by the stepping motor assembly, the cam mechanism has a thread trimming crank, and the thread trimming structure also includes a needle plate thread trimming assembly, a movable knife, a thread trimming guide rail assembly, and a thread trimming transmission assembly. The present invention drives the thread trimming crank of the cam mechanism to rotate by a stepping motor, drives the movement of the slider on the thread trimming guide rail assembly, and drives the movable knife to feed through the thread trimming transmission mechanism to complete the thread trimming. The structure is simple and stable, the transmission efficiency is high, the noise is low, and the position of the needle plate thread trimming assembly is constrained, and the feeding stroke of the movable knife is a straight line, ensuring that the suture of the zigzag sewing machine can be effectively cut at any position, and the feeding action occupies a small space while ensuring a large effective shearing range.

Description

Technical Field

[0001] The invention relates to the technical field of sewing machines, in particular to a thread trimming structure and a zigzag sewing machine with automatic thread trimming and presser foot lifting functions. Background Art

[0002] At present, the thread trimming function used in the sewing machine during operation is generally realized by an electromagnet, which has the problems of slow response speed and high noise. In addition, the stroke of the electromagnet cannot be flexibly changed, and it is easy to jitter during operation, which can easily cause problems such as unbroken thread cutting and jamming.

[0003] Moreover, in the existing sewing machine products, the thread cutting feed is mostly a rotary feed to cut the thread, and the tool will occupy a large movable space. For a zigzag sewing machine in which the needle bar swings left and right to perform herringbone sewing, the position range of the seam is relatively wide. This thread cutting method is prone to the situation where the seam cannot be cut or even cannot be cut. In addition, simply widening the tool to increase the cutting range will make the internal space of the sewing machine too crowded, increasing the design cost. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a thread trimming structure and a zigzag sewing machine with automatic thread trimming and presser foot lifting, wherein the thread trimming function structure is streamlined, occupies less space, and the cutting is flexible and fast.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] A thread trimming structure comprises a stepper motor assembly and a cam mechanism, wherein the cam mechanism is driven to rotate by the stepper motor assembly, the cam mechanism has a thread trimming crank, the thread trimming structure also comprises a needle plate thread trimming assembly, a movable knife, a thread trimming guide rail assembly and a thread trimming transmission assembly, the movable knife is linearly slidably mounted on the needle plate thread trimming assembly, the thread trimming guide rail assembly is fixedly arranged on one side of the stepper motor assembly, the thread trimming guide rail assembly comprises a guide rail and a slider slidably arranged on the guide rail, the slider is connected to one end of the thread trimming transmission assembly, the movable knife is connected to the other end of the thread trimming transmission assembly, and the thread trimming crank has a thread trimming drive stroke for driving the slider to move.

[0007] Compared with the prior art, the advantages of the present invention are:

[0008] A stepper motor drives the trimmer crank of the cam mechanism to rotate, driving the slider to move on the trimmer guide assembly, so as to drive the movable knife to feed through the trimmer transmission mechanism. The structure is simple and stable, the transmission efficiency is high, the noise is low, and the position of the needle plate trimmer assembly is constrained. The feed stroke of the movable knife is a straight line, ensuring that the sewing thread of the zigzag sewing machine can be effectively cut at any position. While ensuring a large effective shearing range, the feed action occupies a small space.

[0009] Furthermore, a stopper is provided on the lower side of the slider, and when the thread trimmer crank is driven by the stepper motor assembly to rotate within the thread trimmer driving stroke, the thread trimmer crank abuts against the stopper and drives the slider to move, with smooth and precise movement and low noise.

[0010] Furthermore, a return spring for returning the slider is sleeved on the guide rail of the thread trimming guide rail assembly, which drives the movable knife to hook the suture and cut it when returning, and the return action is stable and fast.

[0011] Furthermore, a return block is provided on the lower side of the slider, and the return block is located in the return direction of the stop block. The vertical distance between the return block and the rotation center of the thread trimmer crank is greater than the vertical distance between the stop block and the rotation center of the thread trimmer crank, which helps ensure that the slider can return to its initial position every time.

[0012] Furthermore, the wire cutting transmission assembly includes a wire cutting front end connecting rod and a guide rail connecting rod. The middle part of the wire cutting front end connecting rod is fixed by a fastener and can rotate along the fastener. One end of the guide rail connecting rod is connected to one end of the wire cutting front end connecting rod, the slider is connected to the other end of the guide rail connecting rod, and the movable knife is connected to the other end of the wire cutting front end connecting rod. The structure is simple and the transmission is fast.

[0013] A zigzag sewing machine with automatic thread trimming and presser foot lifting functions, comprising the above-mentioned thread trimming structure.

[0014] Furthermore, it includes a stepper motor assembly and a cam mechanism, the cam mechanism is driven to rotate by the stepper motor assembly, the cam mechanism includes a thread trimming crank and a lifting crank, the stepper motor assembly is a dual-output shaft motor, the thread trimming crank and the lifting crank are respectively fixedly mounted on the output shafts on both sides of the stepper motor assembly, one motor realizes bidirectional drive, the structure is simplified and the cost is reduced.

[0015] Furthermore, it also includes a presser foot lifting mechanism, which includes a presser foot and a presser foot lifting transmission assembly, the presser foot lifting transmission assembly is connected to the presser foot, and the lifting crank has a presser foot lifting driving stroke for driving the presser foot lifting transmission assembly to move, and the presser foot lifting action is fast and accurate with low noise.

[0016] Furthermore, the action of the stepper motor assembly is controlled by a control box. In an initial state, the thread trimming crank does not contact the slider, and the lifting crank does not contact the presser foot lifting transmission assembly. When the stepper motor assembly rotates forward, it drives the thread trimming crank to enter the thread trimming drive stroke, and when the stepper motor assembly rotates reversely, it drives the lifting crank to enter the presser foot lifting drive stroke, so that in actual operation, the thread trimming and presser foot lifting actions can be realized in sequence without interfering with each other.

[0017] Furthermore, the presser foot lifting transmission assembly includes a concave connecting rod, which is fixed by a fastener and can rotate along the fastener. When the lifting crank rotates to the presser foot lifting driving stroke under the drive of the stepper motor assembly, the lifting crank presses against one end of the concave connecting rod to drive the concave connecting rod to rotate upward. The other end of the concave connecting rod is connected to a push rod, one end of the push rod is connected to a right lifting block, the middle part of the right lifting block is fixed by a fastener and can rotate along the fastener, the other end of the right lifting block is connected to a pull rod, the other end of the pull rod is connected to a left lifting block, the middle part of the left lifting block is fixed by a fastener and can rotate along the fastener; it also includes a pressing rod, the lower end of the pressing rod is connected to the presser foot, a pressing rod guide block is fixedly connected to the pressing rod, the left lifting block drives the pressing rod guide block to move up and down, and a compression spring is provided on the pressing rod for returning the pressing rod guide block. The return action is stable and fast, and the transmission is fast and smooth. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the wire cutting structure part of an embodiment of the present invention;

[0019] Figure 2 for Figure 1 A schematic diagram of the structure in the A direction;

[0020] Figure 3 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0021] Figure 4 It is a schematic diagram of the overall structure explosion of an embodiment of the present invention.

[0022] Figure numerals: 1, needle plate thread trimming assembly; 2, moving knife; 3, stop block; 4, slider; 5, front end connecting rod of thread trimming; 6, guide rail connecting rod; 7, thread trimming crank; 8, stepping motor assembly; 9, return block; 10, lifting crank; 11, concave connecting rod; 18, compression spring; 19, push rod guide block; 22, push rod; 24, presser foot; 25, left lifting block; 27, pull rod; 31, right lifting block; 34, reset spring; 35, push rod. DETAILED DESCRIPTION

[0023] The specific implementation modes of the present invention are further described below in conjunction with the accompanying drawings to make the technical solutions of the present invention easier to understand and grasp.

[0024] Example:

[0025] Reference Figures 1 to 4As shown, the present embodiment provides a thread trimming structure and a zigzag sewing machine with automatic thread trimming and presser foot lifting, including a thread trimming structure, the thread trimming structure including a stepper motor assembly 8 and a cam mechanism, the action of the stepper motor assembly 8 is controlled by a control box, the cam mechanism is driven to rotate by the stepper motor assembly 8, the cam mechanism includes a thread trimming crank 7 and a lifting crank 10, the stepper motor assembly 8 is a double-output shaft motor, the thread trimming crank 7 and the lifting crank 10 are respectively mounted on the output shafts on both sides of the stepper motor assembly 8, the forward and reverse rotation of the stepper motor assembly 8 is controlled by the control box to control the forward and reverse rotation of the thread trimming crank 7 and the lifting crank 10.

[0026] The thread trimming structure of the present embodiment also includes a needle plate thread trimming assembly 1, a movable knife 2, a thread trimming guide rail assembly and a thread trimming transmission assembly. The movable knife 2 is linearly slidably installed on the needle plate thread trimming assembly 1, so that the feed and return stroke of the movable knife 2 is a straight line, and any position of the stitching of the zigzag sewing machine is located on the stroke of the movable knife 2, thereby ensuring the thread trimming performance and avoiding the situation of continuous cutting or failure to cut.

[0027] The thread trimmer guide rail assembly is fixedly arranged on one side of the stepper motor assembly 8, and the thread trimmer guide rail assembly includes a guide rail and a slider 4 slidably arranged on the guide rail, and a reset spring 34 for returning the slider 4 is sleeved on the guide rail, and a stopper 3 is provided on the slider 4. The stepper motor assembly 8 drives the thread trimmer crank 7 to rotate in the forward direction until the thread trimmer crank 7 abuts against the stopper 3, drives the slider 4 to move and compresses the reset spring 34, and drives the movable knife 2 to complete the feed action through the thread trimmer transmission assembly to hook the suture. This section of the stroke in which the thread trimmer crank 7 drives the slider 4 to move is the thread trimmer drive stroke.

[0028] It should be added that, during long-term use, the return spring 34 may deform and become shorter, making it impossible to drive the slider 4 to return to its initial position. A return block (9) is provided on the lower side of the slider (4), and the return block (9) is located in the return direction of the stop block (3). When the thread trimmer crank 7 returns, the thread trimmer crank 7 reverses and abuts against the return block 9 to drive the slider 4 back to its original position. In addition, the vertical distance between the return block (9) and the rotation center of the thread trimmer crank (7) is greater than the vertical distance between the stop block (3) and the rotation center of the thread trimmer crank (7). The thread trimmer crank 7 will not interfere with the return block 9 during the positive stroke. After the slider 4 returns to its original position at the end of the return stroke, the thread trimmer crank 7 can be smoothly disengaged.

[0029] Furthermore, the wire cutting transmission assembly includes a wire cutting front end connecting rod 5 and a guide rail connecting rod 6, the middle part of the wire cutting front end connecting rod 5 is fixed by a fastener and can rotate along the fastener, one end of the guide rail connecting rod 6 is connected to one end of the wire cutting front end connecting rod 5, the slider 4 is connected to the other end of the guide rail connecting rod 6, and the movable knife 2 is connected to the other end of the wire cutting front end connecting rod 5, the slider 4 moves to pull the guide rail connecting rod 6 to move, and then the wire cutting front end connecting rod 5 rotates around the fastener to drive the movable knife 2 to advance.

[0030] The thread trimmer transmission assembly drives the movable knife 2 to move quickly through a connecting rod transmission, has a simple structure, fast response, stable movement and low noise. The shape and installation point of the thread trimmer transmission assembly are not limited to the diagram in this embodiment. Those skilled in the art can make corresponding improvements according to actual needs. However, if there is no substantial change in the technical content, it should also be regarded as the scope of implementation of the present invention.

[0031] After the cutting is carried out, the stepper motor assembly 8 drives the thread trimming crank 7 to reverse and rotate out of the thread trimming driving stroke. The slider 4 is not resisted by the thread trimming crank 7, but returns to its original position due to the elastic force of the return spring 34, and then drives the movable knife 2 to return through the thread trimming transmission mechanism to cut the suture, thus completing a complete thread trimming return cycle.

[0032] The present embodiment also includes a zigzag sewing machine with automatic thread trimming and presser foot lifting, including a presser foot lifting mechanism, the presser foot lifting mechanism includes a presser foot 24 and a presser foot lifting transmission assembly, the presser foot lifting transmission assembly includes a concave connecting rod 11, the concave connecting rod 11 is fixed by a fastener and can rotate along the fastener, the other end of the concave connecting rod 11 is connected to a push rod 35, one end of the push rod 35 is connected to a right lifting block 31, the middle part of the right lifting block 31 is fixed by a fastener and can rotate along the fastener, The other end of the right lifting block 31 is connected to a pull rod 27, and the other end of the pull rod 27 is connected to a left lifting block 25. The middle part of the left lifting block 25 is fixed by a fastener and can rotate along the fastener; it also includes a pressing rod 22, the lower end of the pressing rod 22 is connected to the presser foot 24, and a pressing rod guide block 19 is fixedly connected to the pressing rod 22. The left lifting block 25 drives the pressing rod guide block 19 to move up and down, and the pressing rod 22 is provided with a compression spring 18 for returning the pressing rod guide block 19.

[0033] The stepper motor assembly 8 reversely drives the lifting crank 10 to rotate until the lifting crank 10 abuts against the concave connecting rod 11 to drive the concave connecting rod 11 to rotate, and drives the presser foot 24 through the presser foot lifting transmission assembly to complete the presser foot lifting action. This section of the stroke in which the lifting crank 10 drives the concave connecting rod 11 to move is the presser foot lifting driving stroke.

[0034] The thread trimming driving stroke and the presser foot lifting driving stroke are respectively in forward and reverse directions, and when the thread trimming crank 7 drives the slider 4 to move, the lifting crank 10 is always not in contact with the concave connecting rod 11, and when the lifting crank 10 drives the concave connecting rod 11 to move, the thread trimming crank 7 is always not in contact with the slider 4, and thus the thread trimming driving stroke and the presser foot lifting driving stroke do not overlap, and the thread trimming action and the presser foot lifting action do not interfere with each other. In actual operation, the stepping motor assembly 8 first rotates forward to complete the thread trimming operation and then reverses to complete the presser foot lifting operation, in order.

[0035] The working principle of the present invention is as follows:

[0036] When the thread trimming instruction is received, the controller controls the stepper motor assembly 8 to rotate forward, driving the thread trimming crank 7 to rotate forward and against the slider 4. The thread trimming crank 7 drives the slider 4 to slide along the guide rail and compresses the reset spring 34. The guide rail connecting rod 6 swings with the movement of the slider 4, thereby driving the front end connecting rod 5 of the thread trimmer to rotate around the fastener, thereby driving the movable knife 2 to advance in a straight line along the needle plate thread trimming assembly 1 to hook the suture; then, the controller controls the stepper motor assembly 8 to reverse, the thread trimming crank 7 reverses and returns, the reset spring 34 rebounds and drives the slider 4 to return, thereby driving the front end connecting rod 5 of the thread trimmer to return through the guide rail connecting rod 6, and then the movable knife 2 returns to cut the suture.

[0037] When the presser foot lifting instruction is received, the controller controls the stepper motor assembly 8 to reverse, driving the lifting crank 10 to rotate and press against the concave connecting rod 11, and the lifting crank 10 lifts the concave connecting rod 11 to rotate an angle to push the top rod 35, thereby driving the right lifting block 31 to rotate and pull the pull rod 27, and the pull rod 27 pulls the left lifting block 25 to rotate an angle, and the left lifting block 25 presses against the lower side of the pressing rod guide block 19 to drive the pressing rod guide block 19 to move up and compress the compression spring 18, thereby The rod 22 drives the presser foot 24 to move upward to complete the presser foot lifting action; after the presser foot is lifted, the controller controls the stepper motor assembly 8 to rotate forward, the lifting crank 10 rotates back, the compression spring 18 rebounds and drives the pressing rod guide block 19 to return, and the presser foot 24 is driven to return through the pressing rod 22, and the pressing rod guide block 19 returns to drive the left lifting block 25 to return, and the right lifting block 31 is driven to return through the pull rod 27, and then the right lifting block 31 presses the push rod 35 to return, and then the concave connecting rod 11 returns.

[0038] The above are only typical examples of the present invention. In addition, the present invention may also have many other specific implementations. Any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the scope of protection required by the present invention.

Claims

1. A zigzag sewing machine with automatic thread trimming and presser foot lifting, characterized in that: The invention comprises a thread trimming structure, wherein the thread trimming structure comprises a stepping motor assembly (8) and a cam mechanism, wherein the cam mechanism is driven by the stepping motor assembly (8) to rotate, and the cam mechanism has a thread trimming crank (7). The thread trimming structure also comprises a needle plate thread trimming assembly (1), a movable knife (2), a thread trimming guide rail assembly and a thread trimming transmission assembly, wherein the movable knife (2) is linearly slidably mounted on the needle plate thread trimming assembly (1), and the thread trimming guide rail assembly is fixedly arranged on one side of the stepping motor assembly (8). The thread trimming guide rail assembly comprises a guide rail and a slider (4) slidably arranged on the guide rail, wherein the slider (4) is connected to one end of the thread trimming transmission assembly, and the movable knife (2) is connected to the other end of the thread trimming transmission assembly, and the thread trimming crank (7) has a thread trimming driving stroke for driving the slider (4) to move. A stopper (3) is provided on the lower side of the slider (4); when the thread trimmer crank (7) is driven by the stepper motor assembly (8) to rotate within the thread trimmer driving stroke, the thread trimmer crank (7) abuts against the stopper (3) and drives the slider (4) to move; A return spring (34) for returning the slider (4) is sleeved on the guide rail of the thread trimming guide rail assembly; A return block (9) is provided on the lower side of the slider (4), the return block (9) is located in the return direction of the stop block (3), and the vertical distance between the return block (9) and the rotation center of the thread trimmer crank (7) is greater than the vertical distance between the stop block (3) and the rotation center of the thread trimmer crank (7); The thread trimmer transmission assembly comprises a thread trimmer front end connecting rod (5) and a guide rail connecting rod (6), the middle portion of the thread trimmer front end connecting rod (5) is fixed by a fastener and can rotate along the fastener, one end of the guide rail connecting rod (6) is connected to one end of the thread trimmer front end connecting rod (5), the slider (4) is connected to the other end of the guide rail connecting rod (6), and the movable knife (2) is connected to the other end of the thread trimmer front end connecting rod (5); The cam mechanism further comprises a lifting crank (10), the stepping motor assembly (8) is a double-output shaft motor, and the thread trimming crank (7) and the lifting crank (10) are respectively fixedly sleeved on the output shafts on both sides of the stepping motor assembly (8); It also includes a presser foot lifting mechanism, the presser foot lifting mechanism including a presser foot (24) and a presser foot lifting transmission assembly, the presser foot lifting transmission assembly is connected to the presser foot (24), and the lifting crank (10) has a presser foot lifting driving stroke for driving the presser foot lifting transmission assembly to move; The movement of the stepper motor assembly (8) is controlled by a control box. In an initial state, the thread trimmer crank (7) does not contact the slider (4), and the lifting crank (10) does not contact the presser foot lifting transmission assembly. When the stepper motor assembly (8) rotates forward, it drives the thread trimmer crank (7) to enter the thread trimmer driving stroke. When the stepper motor assembly (8) rotates reversely, it drives the lifting crank (10) to enter the presser foot lifting driving stroke.

2. A zigzag sewing machine with automatic thread trimming and presser foot lifting according to claim 1, characterized in that: The presser foot lifting transmission assembly comprises a concave connecting rod (11), the concave connecting rod (11) being fixed by a fastener and being rotatable along the fastener; when the lifting crank (10) is driven by the stepping motor assembly (8) to rotate within the presser foot lifting driving stroke, the lifting crank (10) abuts against one end of the concave connecting rod (11) to drive the concave connecting rod (11) to rotate upward; the other end of the concave connecting rod (11) is connected to a push rod (35), one end of the push rod (35) is connected to a right lifting block (31), the middle part of the right lifting block (31) is fixed by a fastener and being rotatable along the fastener; The fastener rotates, the other end of the right lifting block (31) is connected to a pull rod (27), the other end of the pull rod (27) is connected to a left lifting block (25), the middle part of the left lifting block (25) is fixed by a fastener and can rotate along the fastener; it also includes a pressing rod (22), the lower end of the pressing rod (22) is connected to the presser foot (24), the pressing rod (22) is fixedly connected to a pressing rod guide block (19), the left lifting block (25) drives the pressing rod guide block (19) to move up and down, and the pressing rod (22) is sleeved with a compression spring (18) for returning the pressing rod guide block (19).

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