Thread trimming mechanism of sewing machine

Abstract

The utility model relates to and discloses a thread trimming mechanism of a sewing machine, which comprises a fixed frame and a motor arranged on the fixed frame, the fixed frame is also provided with a fixed knife for trimming threads, the interior of the motor is connected with one end of a rotating shaft, the other end of the rotating shaft is connected with a turntable, and the turntable is provided with a cam mechanism; a transmission mechanism, a movable cutter and a fixed cutter are further arranged on the fixing frame, the cam mechanism can drive the transmission mechanism and drive the movable cutter to separate and pick a plurality of wire harnesses, the separated and picked wire harnesses are pushed to the fixed cutter, and wire cutting is achieved. The thread trimming mechanism of the sewing machine aims at solving the problems that an existing thread trimming mechanism is large in occupied space and relatively low in response speed.

Description

TECHNICAL FIELD

[0001] The utility model relates to sewing machine technical field especially relates to a sewing machine thread trimming mechanism. BACKGROUND

[0002] In the sewing process, the automatic cutting of the thread bundle is one of the important steps for the sewing machine to complete the sewing cycle. The main function of the sewing machine thread trimming mechanism is to automatically cut the sewing thread after sewing is completed, ensuring that the thread end is neat and avoiding the thread end being too long or too short, thereby ensuring the quality and appearance of the sewing product. The design of the thread trimming mechanism directly affects the automation level and production efficiency of the sewing machine, especially in high-speed sewing or mass production, the automatic thread trimming mechanism can significantly improve the production efficiency.

[0003] The traditional thread trimming mechanism usually uses a cylinder to drive a movable knife for thread trimming operation, which has the following shortcomings: first, the cylinder driving method needs to be equipped with a gas source system, including a gas pump, a gas pipe and a gas valve, which not only increases the complexity and cost of the equipment, but also occupies more space. Secondly, the response speed of the cylinder drive is relatively slow, which is difficult to meet the needs of high-speed sewing, resulting in low thread trimming efficiency. In addition, the precision and stability of the cylinder drive are poor, which is easily affected by gas pressure fluctuations, resulting in inaccurate thread trimming or failure. SUMMARY

[0004] The utility model aims at providing a sewing machine thread trimming mechanism to solve the problems of large space occupation and relatively slow response speed of the existing thread trimming mechanism.

[0005] The utility model realizes the following technical scheme:

[0006] A sewing machine thread trimming mechanism, comprising a fixed frame and a motor arranged on the fixed frame, a fixed knife for thread trimming is further arranged on the fixed frame, one end of a rotating shaft connected to the motor, the other end of the rotating shaft is connected to a rotating disc, a cam mechanism is arranged on the rotating disc; a transmission mechanism, a movable knife and a fixed knife are further arranged on the fixed frame, the cam mechanism can drive the transmission mechanism and drive the movable knife to separate and pick a plurality of thread bundles, and push the separated and picked thread bundles to the fixed knife to realize thread trimming.

[0007] The utility model has a better scheme: the cam mechanism comprises an annular wall and a disc arranged on the rotating disc, the annular wall and the disc are coincident with the center of the rotating disc; the inner surface of the annular wall is provided with a protruding part, the outer wall of the disc is provided with a recessed part matched with the shape of the protruding part; the annular groove is formed between the inner surface of the annular wall and the outer wall of the disc.

[0008] The present invention has a better solution: the transmission mechanism includes a rocker mechanism and a straight rod, the rocker mechanism includes a fixed shaft, a first rocker and a second rocker; the fixed shaft is fixed on a fixed frame; one end of the first rocker is fixed with a slider matching the annular groove, the other end of the first rocker is connected to one end of the second rocker, and the other end of the second rocker is hinged with a straight rod; the connection between the first rocker and the second rocker is hinged to the fixed shaft.

[0009] The present invention has a better solution: one end of the straight rod is hinged to the second rocker, and the other end of the straight rod is connected to a movable knife.

[0010] The present invention has a better solution: the movable knife includes a connecting section and a shearing section connected to each other, one end of the connecting section is hinged to the straight rod, and the other end of the connecting section is hinged to the fixing frame.

[0011] The present invention has a better solution: slots are provided on both sides of the second rocker.

[0012] The present invention has a better solution: a guide plate is provided on the fixing frame, and a guide cylinder is provided on the guide plate.

[0013] The present invention has a better solution: the angle between the connecting section and the shearing section is an acute angle.

[0014] The present invention has a better solution: one end of the shearing section is connected to the connecting section, and the other end of the shearing section is provided with a thread picking head and a thread collecting head.

[0015] Compared with the existing technology, the present invention has the following advantages and beneficial effects: the present invention uses a motor to drive the rotating shaft to drive the cam mechanism on the turntable, accurately controlling the transmission mechanism to achieve efficient and stable thread trimming operations. Specifically, compared with traditional cylinder drives, motor drives have a simpler structure, faster response speed, higher control accuracy, and are not affected by air pressure fluctuations, resulting in better stability. At the same time, the coordination of the cam mechanism and the transmission mechanism makes the entire thread trimming process smooth, low-noise, and easy to maintain and adjust. This solution improves the automation level and production efficiency of the sewing machine, extends the service life of the equipment, and reduces the cost of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:

[0017] Figure 1 This is a schematic diagram of the installation position of the thread trimming mechanism of the present invention on the fixed frame;

[0018] Figure 2It is the overall structure schematic view of the thread trimming mechanism of the utility model;

[0019] Figure 3 It is the structure schematic view of the first rocker and the second rocker of the utility model;

[0020] Figure 4 It is the structure schematic view of the cam mechanism of the utility model;

[0021] Figure 5 It is the relative position schematic view of the straight rod, the movable cutter, the fixed cutter, the guide disc and the guide cylinder of the utility model;

[0022] Figure 6 It is the structure schematic view of the movable cutter of the utility model.

[0023] The represented by the reference signs are:

[0024] 1, fixed frame, 2, motor, 21, rotating shaft, 3, rotating disc, 31, annular wall, 311, protruding part, 32, disc, 321, recessed part, 4, first rocker, 41, sliding block, 5, second rocker, 51, slot, 6, straight rod, 7, movable cutter, 71, thread picking head, 72, thread collecting head, 8, fixed cutter, 9, guide disc, 91, guide cylinder. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme of the embodiments of the utility model will be described clearly and completely below in combination with the drawings of the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the described embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the utility model. The illustrative embodiments of the utility model and the description thereof are only used to explain the utility model, and do not limit the utility model. It should be noted that the utility model has been in the actual research and development stage.

[0026] Unless otherwise defined, the technical terms or scientific terms used in the utility model should be understood as the usual meaning by those skilled in the art to which the utility model belongs. The "first", "second" and similar words used in the utility model do not represent any order, quantity or importance, but are only used to distinguish different components. "Include" or "contain" and similar words mean that the elements or objects before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0027] Traditional thread trimming mechanisms mainly rely on a cylinder to drive a movable knife for thread trimming operation. However, this design has obvious defects. First, cylinder driving requires an additional air supply system, including air pump, air pipe and air valve, which not only increases the complexity and cost of the equipment, but also occupies more space. Second, the response speed of the cylinder is slow, which is difficult to meet the needs of high-speed sewing, resulting in low thread trimming efficiency. In addition, the precision and stability of the cylinder driving are greatly affected by air pressure fluctuations, which can easily lead to inaccurate thread trimming or failure, affecting sewing quality and production efficiency.

[0028] Embodiments:

[0029] As shown in Figure 1 , a thread trimming mechanism of a sewing machine includes a fixed frame 1 and a motor 2 arranged on the fixed frame 1. The fixed frame 1 is also provided with a fixed knife 8 for thread trimming. One end of a rotating shaft 21 inside the motor 2 is connected, and the other end of the rotating shaft 21 is connected with a rotating disc 3. The rotating disc 3 is provided with a cam mechanism. The fixed frame 1 is also provided with a transmission mechanism, a movable knife 7 and a fixed knife 8. The cam mechanism can drive the transmission mechanism and drive the movable knife 7 to separate and pick multiple thread bundles, and push the separated thread bundles to the fixed knife 8 to achieve thread trimming.

[0030] The motor 2 is the power source of the entire thread trimming mechanism, which provides continuous rotary power. The rotating shaft 21 connects the motor 2 and the rotating disc 3, which plays a role in transmitting power. The cam mechanism on the rotating disc 3 is a key component that determines the motion trajectory of the subsequent transmission mechanism. This scheme drives the rotating shaft 21 to rotate by the motor 2, which drives the cam mechanism on the rotating disc 3 to move. The motion trajectory of the cam mechanism precisely controls the motion of the transmission mechanism, thereby driving the movable knife 7 to pick and collect threads, and finally achieving automatic thread trimming. Compared with the traditional cylinder driving method, the motor 2 driving does not require a complex air supply system, simplifying the equipment structure; the motor 2 can be quickly started and stopped, adapting to the needs of high-speed sewing; the motion of the motor 2 can be precisely adjusted by the control system to ensure the accuracy and consistency of thread trimming; the motor 2 driving is not affected by air pressure fluctuations, and has higher stability.

[0031] As shown in Figure 2 and Figure 4 , the further optimization of the present embodiment includes an annular wall 31 and a disc 32 arranged on the rotating disc 3. The annular wall 31 and the disc 32 are coaxial with the center of the rotating disc 3. The inner surface of the annular wall 31 is provided with a protruding part 311, and the outer wall of the disc 32 is provided with a recessed part 321 matching the shape of the protruding part 311. The inner surface of the annular wall 31 and the outer wall of the disc 32 form an annular groove.

[0032] The inner surface of the annular wall 31 is provided with a protrusion 311, and the outer wall of the disc 32 is provided with a recess 321 that matches the shape of the protrusion 311. Together, these two forms an annular groove. The groove guides the movement of the slider 41. The cam mechanism's annular groove allows the slider 41 to slide within it, thereby converting the rotational motion of the turntable 3 into the swinging motion of the first rocker 4.

[0033] like Figure 2 and Figure 3 As shown, this embodiment is further optimized, the transmission mechanism includes a rocker mechanism and a straight rod, the rocker mechanism includes a fixed shaft, a first rocker 4 and a second rocker 5; the fixed shaft is fixed to the fixed frame 1; one end of the first rocker 4 is fixed with a slider 41 matching the annular groove, the other end of the first rocker 4 is connected to one end of the second rocker 5, and the other end of the second rocker 5 is hinged with a straight rod; the connection between the first rocker 4 and the second rocker 5 is hinged to the fixed shaft.

[0034] The transmission mechanism converts the sliding motion of the slider 41 into the swinging motion of the second rocker 5 through the hinge point between the first rocker 4 and the second rocker 5. The swinging motion of the second rocker 5 is converted into linear motion by a straight rod, thereby driving the movable knife 7 to pick up and gather the thread. The design of the four-link mechanism 6 ensures smoother movement, reducing impact and vibration during movement. The combined structure of the rocker mechanism and straight rod is compact and takes up little space. By precisely designing the length of the rocker and the position of the hinge point, the movement of the movable knife 7 can be precisely controlled.

[0035] like Figure 5 As shown, in a further optimization of this embodiment, one end of the straight rod is hinged to the second rocker 5, and the other end of the straight rod is connected to the movable blade 7. When the second rocker 5 swings, the straight rod receives the swinging motion through the hinge point and converts it into linear motion. The linear motion of the straight rod directly drives the movable blade 7 to rotate, realizing the thread picking and gathering functions.

[0036] The straight rod is a simple connecting rod 6 structure that is easy to manufacture and install; the straight rod transmits linear motion smoothly, reducing impact and vibration during movement; by accurately designing the length of the straight rod and the position of the hinge point, precise control of the movement of the movable blade 7 can be achieved.

[0037] like Figure 6 As shown, this embodiment is further optimized, the movable knife 7 includes a connecting section and a shearing section connected to each other, one end of the connecting section is hinged to the straight rod, and the other end of the connecting section is hinged to the fixing frame 1.

[0038] It needs to be clear that one end of the connecting segment is hinged to the straight rod, and the other end is hinged to the fixed frame 1, forming a rotating fulcrum. The cutting segment is connected with the connecting segment, and its function is to perform the actual cutting operation. The structure design of the movable knife 7 piece enables it to realize rotary motion, thereby completing the thread picking and thread collecting functions.

[0039] The specific working principle is as follows:

[0040] Rotary motion: the two ends of the connecting segment are hinged to the straight rod and the fixed frame 1 respectively, and the linear motion of the straight rod is converted into the rotary motion of the movable knife 7 piece through the connecting segment.

[0041] Thread picking and collecting: during the rotation of the cutting segment, the thread bundle to be cut is picked out by the thread picking head 71 and collected at the thread collecting head 72.

[0042] Cutting operation: the thread bundle is collected at the fixed knife 8 piece by the thread collecting head 72, and the cutting edge of the fixed knife 8 piece completes the cutting operation.

[0043] The structure design of the movable knife 7 piece is compact and occupies small space; through the design of the hinge point, the movable knife 7 piece can realize flexible rotary motion and adapt to different cutting needs; the combination design of the connecting segment and the cutting segment integrates the thread picking, thread collecting and cutting functions in one component, simplifying the mechanism design.

[0044] As shown in Figure 3 , the further optimization of the present embodiment is that the second rocker 5 is provided with a slot 51 on both sides. It needs to be clear that the slot 51 functions to reduce the weight of the rocker, reduce inertia, improve motion response speed, and can be used for installing other components or lubrication.

[0045] As shown in Figure 5 , the further optimization of the present embodiment is that the fixed frame 1 is provided with a guide disc 9, and the guide disc 9 is provided with a guide cylinder 91. The guide disc 9 and the guide cylinder 91 are used to guide the path of the thread bundle, ensuring that the thread bundle maintains the correct direction and position during the thread picking and cutting process.

[0046] The further optimization of the present embodiment is that the included angle between the connecting segment and the cutting segment is an acute angle. It needs to be clear that the included angle design between the connecting segment and the cutting segment is to optimize the motion trajectory and function of the movable knife 7 piece; the acute angle design makes the motion trajectory of the movable knife 7 piece more reasonable, ensuring the smooth operation of the thread picking and thread collecting; effectively reducing the rotation angle of the movable knife 7 piece, improving the cutting efficiency; making the overall structure of the movable knife 7 piece more compact, occupying less space.

[0047] As shown in Figure 6 , the further optimization of the present embodiment is that one end of the cutting segment is connected with the connecting segment, and the other end of the cutting segment is provided with a thread picking head 71 and a thread collecting head 72.

[0048] It should be noted that the thread picking head 71 is used to pick out the thread bundle that needs to be cut, and the thread collecting head 72 is used to concentrate the picked thread bundle to the fixed knife 8 piece; the thread picking head 71 picks out the thread bundle that needs to be cut, and ensures that the thread bundle maintains the correct position during the thread cutting process; the thread collecting head 72 concentrates the picked thread bundle to the fixed knife 8 piece, and prepares for the thread cutting operation.

[0049] Working process:

[0050] S1. The motor 2 starts and drives the rotating shaft 21 to rotate. The motor 2 serves as a power source, providing continuous and stable rotating power to ensure efficient operation of the entire thread cutting process.

[0051] S2. The rotating motion of the rotating shaft 21 is transmitted to the rotating disc 3. The rotating disc 3 is provided with a cam mechanism designed to accurately control the subsequent transmission motion.

[0052] S3. When the rotating disc 3 rotates, the annular groove of the cam mechanism guides the sliding block 41 to slide in the groove. The sliding motion of the sliding block 41 converts the rotating motion of the rotating disc 3 into the swinging motion of the first rocker 4.

[0053] S4. The swinging of the first rocker 4 drives the second rocker 5 to swing through the hinge point. The swinging motion of the second rocker 5 is converted into linear motion through the straight rod.

[0054] S5. The linear motion of the straight rod directly drives the rotating motion of the movable knife 7 piece. During the rotation of the movable knife 7 piece, the thread picking head 71 picks out the thread bundle that needs to be cut and concentrates it to the thread collecting head 72.

[0055] S6. The blade on the fixed knife 8 piece cooperates with the thread collecting head 72 of the movable knife 7 piece to cut the concentrated thread bundle, completing the thread cutting operation.

[0056] S7. The hole in the guide disc 9 guides the path of the thread bundle during the entire process, ensuring that the thread bundle maintains the correct direction and position during the thread picking and cutting process.

[0057] S8. After the thread cutting is completed, the sewing machine continues the next round of sewing cycle, and the thread cutting mechanism returns to the initial state, waiting for the next work instruction.

[0058] The above examples are only used to illustrate the technical solutions of the present disclosure, rather than limit them; although the present disclosure has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for some technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure. The following points need to be explained: only the structures involved in the embodiments of the present utility model are involved in the drawings of the embodiments of the present utility model, and other structures can refer to the usual design. In the case of no conflict, the features in the same embodiment and different embodiments of the present utility model can be combined with each other. The above is only a demonstrative implementation manner of the present utility model, rather than used to limit the protection scope of the present utility model, and the protection scope of the present utility model is determined by the appended claims.

Claims

1. A thread cutting mechanism of a sewing machine, comprising a fixed frame (1) and a motor (2) arranged on the fixed frame (1), and a fixed cutter (8) for cutting threads, characterized in that, one end of a rotating shaft (21) is connected to the motor (2), and the other end of the rotating shaft (21) is connected to a rotating disc (3), and a cam mechanism is arranged on the rotating disc (3); a transmission mechanism, a movable cutter (7) and the fixed cutter (8) are further arranged on the fixed frame (1), and the cam mechanism can drive the transmission mechanism and drive the movable cutter (7) to separate and pick a plurality of thread bundles, and push the separated and picked thread bundles to the fixed cutter (8) to cut threads.

2. A thread trimming mechanism for a sewing machine according to claim 1, wherein the cam mechanism comprises an annular wall (31) and a disc (32) arranged on the rotating disc (3), and the annular wall (31) and the disc (32) are coaxial with the center of the rotating disc (3); a protruding portion (311) is arranged on the inner surface of the annular wall (31), and a recessed portion (321) matching the shape of the protruding portion (311) is arranged on the outer wall of the disc (32); and an annular groove is formed between the inner surface of the annular wall (31) and the outer wall of the disc (32).

3. A thread trimming mechanism for a sewing machine as defined in claim 2, wherein the transmission mechanism comprises a rocker mechanism and a straight rod (6), the rocker mechanism comprises a fixed shaft, a first rocker (4) and a second rocker (5); the fixed shaft is fixed on the fixed frame (1); one end of the first rocker (4) is fixed with a sliding block (41) matching the annular groove, the other end of the first rocker (4) is connected to one end of the second rocker (5), and the other end of the second rocker (5) is hingedly connected with the straight rod (6); and the connection between the first rocker (4) and the second rocker (5) is hingedly connected with the fixed shaft.

4. A thread trimming mechanism for a sewing machine according to claim 3, wherein one end of the straight rod (6) is hingedly connected with the second rocker (5), and the other end of the straight rod (6) is connected with the movable cutter (7).

5. A thread trimming mechanism for a sewing machine according to claim 4, wherein the movable cutter (7) comprises a connecting section and a cutting section connected with each other, one end of the connecting section is hingedly connected to the straight rod (6), and the other end of the connecting section is hingedly connected to the fixed frame (1).

6. A thread trimming mechanism for a sewing machine according to claim 5, wherein the second rocker (5) is provided with a slot (51) on both sides.

7. A thread trimming mechanism for a sewing machine according to claim 6 wherein, a guide disc (9) is arranged on the fixed frame (1), and a guide cylinder (91) is arranged on the guide disc (9).

8. The thread trimming mechanism of claim 5 wherein, the included angle between the connecting section and the cutting section is an acute angle.

9. A thread trimming mechanism for a sewing machine according to claim 8, wherein one end of the cutting section is connected with the connecting section, and the other end of the cutting section is provided with a thread picking head (71) and a thread collecting head (72).

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