Thread trimming, presser foot lifting and stitch length adjustment mechanism for a sewing machine
By adopting a stitch length adjustment cam design in the stitch length adjustment mechanism of the sewing machine, the wear problem caused by sliding friction between the slider and the groove is solved, and the long service life of the component is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TAIZHOU SUPU ELECTROMECHANICAL CO LTD
- Filing Date
- 2025-08-12
- Publication Date
- 2026-07-14
AI Technical Summary
In existing sewing machine stitch length adjustment mechanisms, the sliding friction contact between the slider and the groove leads to severe wear of the components and a short service life.
The design employs a cam-based needle pitch adjustment mechanism. By using rolling friction contact between the cam and the needle pitch adjustment section, sliding friction contact is avoided, thus extending the service life of the components.
This reduces wear between the stitch pitch adjustment cam and the stitch pitch adjustment part, extending the service life of the components.
Smart Images
Figure CN224494525U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of sewing machine technology, and specifically to a sewing machine thread cutting, presser foot lifting, and stitch length adjustment mechanism. Background Technology
[0002] A sewing machine is a machine that sews fabric together using thread. A sewing machine includes a needle bar mechanism, thread take-up mechanism, feed mechanism, thread hooking mechanism, presser foot lifting mechanism, stitch length adjustment mechanism, and thread cutting mechanism. With the development of automation, these mechanisms have been gradually improved and equipped with drive components, including motors, electromagnets, cylinders, and hydraulic cylinders. In the stitch length adjustment mechanism, adjusting the stitch length to a negative value enables the sewing machine to reverse stitch.
[0003] In existing designs, the motor typically drives the stitch length adjustment mechanism through the cooperation of a slider and a groove. For example, Chinese Utility Model Patent No. CN202123112536.7 discloses a sewing machine and its thread-cutting, presser foot lifting, and stitch length adjustment mechanism, including a frame on which a thread-cutting assembly, a presser foot lifting assembly, and a stitch length adjustment assembly are mounted. A motor is also mounted at the lower part of the frame. The second output shaft of the motor extends forward and drives the thread-cutting assembly, while the first output shaft extends backward and drives the presser foot lifting assembly and the stitch length adjustment assembly. A first crank is mounted on the first output shaft, which drives the stitch length adjustment assembly. A first support shaft is provided on one side of the swing seat of the stitch length adjustment assembly, which drives the swing seat to swing within a set angle. A first actuating element is provided at the end of the first support shaft facing the motor, and a first groove is formed on the first actuating element. A slider is disposed in the first groove, and the slider is disposed at the outer end of the first crank.
[0004] When the motor drives the first actuating component to rotate via the first crank, and then drives the needle pitch adjustment component, the inner wall of the first slide groove can always restrict the movement of the slider, so that the slider can only move back and forth in a straight line along the extension direction of the first slide groove. This makes the rotation of the first actuating component by the first crank more stable. During the operation of the motor, since the slider always maintains sliding friction contact with the slide groove, the two are prone to wear, resulting in a short service life of the components. Therefore, further improvements to its structure are needed. Utility Model Content
[0005] The purpose of this invention is to provide a thread-cutting, presser foot lifting, and stitch length adjustment mechanism for a sewing machine, which solves the problem of easy wear of the slider by using a stitch length adjustment cam.
[0006] The purpose of this utility model is achieved as follows: A thread-cutting, presser foot lifting, and stitch length adjustment mechanism for a sewing machine includes a machine body, a stitch length adjustment component, and a thread-cutting component. A stepper motor is installed at the lower part of the machine body, and a main shaft is installed inside the stepper motor. One end of the main shaft is equipped with a thread-cutting crank for driving the thread-cutting component, and the other end of the main shaft is equipped with a stitch length adjustment cam. The stitch length adjustment component includes a swing seat, an adjustment shaft is provided on one side of the swing seat, and a stitch length crank is installed on the outer periphery of the other end of the adjustment shaft. A stitch length connecting rod one is hinged to the other end of the stitch length crank, a stitch length connecting rod two is hinged to the other end of the stitch length connecting rod one, and a hinge pin is hinged to the other end of the stitch length connecting rod two. The other end of the hinge pin is fixedly connected to the housing of the stepper motor, and a stitch length adjustment part for the stitch length adjustment cam to push is provided on the stitch length connecting rod two.
[0007] Preferably, the stitch pitch adjustment part is a stitch pitch adjustment push column, which is rotatably disposed in the middle of the stitch pitch connecting rod two via a rotating shaft.
[0008] Preferably, the needle pitch adjusting cam includes a needle pitch adjusting convex portion and a free stroke portion.
[0009] Preferably, the adjusting shaft is rotatably inserted into the machine body, and a return torsion spring is installed on the outer periphery of one end of the adjusting shaft. One end of the return torsion spring abuts against the machine body, and the other end of the return torsion spring abuts against the needle pitch crank.
[0010] Preferably, the wire cutting assembly includes a wire cutting shaft rotatably disposed within the machine body, one end of the wire cutting shaft being connected to a scissor mechanism, and the other end of the wire cutting shaft being equipped with a wire cutting transmission component for being driven by a wire cutting crank.
[0011] Preferably, a wire-cutting push column is installed on the side of the wire-cutting crank, and a through hole is provided in the wire-cutting transmission component for the wire-cutting push column to move. The inner wall of the through hole is provided with a working wall for the wire-cutting push column to push.
[0012] The outstanding and beneficial technical effects of this utility model compared to the prior art are:
[0013] This invention utilizes a design for a stitch pitch adjustment cam. When stitch pitch adjustment is required, the motor drives the stitch pitch adjustment cam to rotate via the main shaft. This rotation, in turn, drives the stitch pitch adjustment part to rotate the second stitch pitch linkage. The angle of the swing seat is then adjusted via the first stitch pitch linkage, the stitch pitch crank, and the adjustment shaft, thereby achieving stitch pitch adjustment. Compared to existing technologies, the stitch pitch adjustment cam and the stitch pitch adjustment part do not always maintain sliding friction contact, which reduces wear between them and extends the service life of the components. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the structure of this utility model.
[0015] Figure 2This is a schematic diagram of the internal mechanism of this utility model.
[0016] Figure 3 This is a schematic diagram of the stitch length adjustment assembly and the thread cutting assembly.
[0017] Reference numerals: 1-Machine body; 2-Pitch adjustment assembly; 3-Thread cutting assembly; 4-Stepper motor; 5-Main shaft; 6-Thread cutting crank; 7-Pitch adjustment cam; 8-Swing seat; 9-Adjustment shaft; 10-Pitch crank; 11-Pitch linkage one; 12-Pitch linkage two; 13-Hinge column; 14-Pitch adjustment part; 15-Pitch adjustment push column; 16-Rotating shaft; 17-Pitch adjustment protrusion; 18-Free stroke part; 19-Reset torsion spring; 20-Thread cutting shaft; 21-Scissors mechanism; 22-Thread cutting transmission component; 23-Thread cutting push column; 24-Through hole; 25-Working wall. Detailed Implementation
[0018] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.
[0019] like Figure 1-3 As shown, a sewing machine's thread cutting, presser foot lifting, and stitch length adjustment mechanism includes a machine body 1. A stitch length adjustment assembly 2 and a thread cutting assembly 3 are disposed within the machine body 1. A stepper motor 4 is mounted on the lower part of the machine body 1. A main shaft 5 is disposed within the stepper motor 4. A thread cutting crank 6 for driving the thread cutting assembly 3 is mounted on one end of the main shaft 5. A stitch length adjustment cam 7 is mounted on the other end of the main shaft 5. The stitch length adjustment assembly 2 includes a swing seat 8. An adjustment shaft 9 is disposed on one side of the swing seat 8. A stitch length crank 10 is mounted on the outer periphery of the other end of the adjustment shaft 9. A stitch length connecting rod 11 is hinged to the other end of the stitch length crank 10. A stitch length connecting rod 2 12 is hinged to the other end of the stitch length connecting rod 11. A hinge post 13 is hinged to the other end of the stitch length connecting rod 2 12. The other end of the hinge post 13 is fixedly connected to the housing of the stepper motor 4. A stitch length adjustment part 14 for being pushed by the stitch length adjustment cam 7 is disposed on the stitch length connecting rod 2 12.
[0020] This invention utilizes a design for a stitch pitch adjustment cam. When stitch pitch adjustment is required, the motor drives the stitch pitch adjustment cam 7 to rotate via the main shaft 5. This, in turn, drives the stitch pitch adjustment part 14 to rotate the stitch pitch connecting rod 12. The angle of the swing seat 8 is then adjusted via the stitch pitch connecting rod 11, the stitch pitch crank 10, and the adjustment shaft 9, thereby achieving stitch pitch adjustment. Compared to existing technologies, the stitch pitch adjustment cam 7 and the stitch pitch adjustment part 14 do not always maintain sliding friction contact, which reduces wear between them and extends the service life of the components.
[0021] The stitch pitch adjustment part 14 is a stitch pitch adjustment push column 15. The stitch pitch adjustment push column 15 is rotatably disposed in the middle of the stitch pitch connecting rod 12 via a rotating shaft 16, so that the stitch pitch adjustment cam 7 and the stitch pitch adjustment push column 15 are in rolling friction contact mode, which can greatly reduce frictional resistance.
[0022] The stitch length adjustment cam 7 includes a stitch length adjustment convex part 17 and a free stroke part 18. The stitch length adjustment convex part 17 is used to push the stitch length adjustment part 14 to move during the rotation of the stitch length adjustment cam 7. The free stroke part 18 is used to avoid the stitch length adjustment part 14 when the thread cutting assembly 3 performs the thread cutting action, so that it will not touch the stitch length adjustment part 14 and the stitch length linkage remains stationary.
[0023] The adjusting shaft 9 is rotatably inserted into the machine body 1. A reset torsion spring 19 is installed on the outer periphery of one end of the adjusting shaft 9. One end of the reset torsion spring 19 abuts against the machine body 1, and the other end of the reset torsion spring 19 abuts against the needle pitch crank 10 to realize the automatic reset function.
[0024] The wire cutting assembly 3 includes a wire cutting shaft 20 rotatably disposed within the body 1. One end of the wire cutting shaft 20 is connected to a scissor mechanism 21, and the other end of the wire cutting shaft 20 is equipped with a wire cutting transmission component 22 that is driven by the wire cutting crank 6.
[0025] The side of the wire-cutting crank 6 is equipped with a wire-cutting push column 23. The wire-cutting transmission component 22 has a through hole 24 for the wire-cutting push column 23 to move. The inner wall of the through hole 24 is provided with a working wall 25 for the wire-cutting push column 23 to push. In actual operation, when the motor spindle drives the wire-cutting crank 6 to rotate back and forth on the inner wall of the through hole 24, it will drive the wire-cutting shaft 20 to rotate through the working wall 25, thereby enabling the scissor mechanism 21 to perform the wire-cutting action.
[0026] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.
Claims
1. A thread-cutting, presser foot-lifting, and stitch length adjustment mechanism for a sewing machine, characterized in that, The machine includes a body (1), inside which are a stitch length adjustment assembly (2) and a thread cutting assembly (3). A stepper motor (4) is installed at the lower part of the body (1), and a spindle (5) is installed inside the stepper motor (4). A thread cutting crank (6) for driving the thread cutting assembly (3) is installed at one end of the spindle (5), and a stitch length adjustment cam (7) is installed at the other end of the spindle (5). The stitch length adjustment assembly (2) includes a swing seat (8), and an adjustment shaft (9) is provided on one side of the swing seat (8). A needle pitch crank (10) is installed on the outer periphery of the other end of the adjusting shaft (9). A needle pitch connecting rod one (11) is hinged to the other end of the needle pitch crank (10). A needle pitch connecting rod two (12) is hinged to the other end of the needle pitch connecting rod two (12). A hinge pin (13) is hinged to the other end of the needle pitch connecting rod two (12). The other end of the hinge pin (13) is fixedly connected to the housing of the stepper motor (4). A needle pitch adjusting part (14) for the needle pitch adjusting cam (7) to push is provided on the needle pitch connecting rod two (12).
2. The thread-cutting, presser foot-lifting, and stitch length adjustment mechanism of the sewing machine according to claim 1, characterized in that: The needle pitch adjustment part (14) is a needle pitch adjustment push column (15), which is rotatably disposed in the middle of the needle pitch connecting rod (12) via a rotating shaft (16).
3. The thread-cutting, presser foot-lifting, and stitch length adjustment mechanism of the sewing machine according to claim 1, characterized in that: The needle pitch adjusting cam (7) includes a needle pitch adjusting convex part (17) and a free stroke part (18).
4. The thread-cutting, presser foot-lifting, and stitch length adjustment mechanism of the sewing machine according to claim 1, characterized in that: The adjusting shaft (9) is rotatably inserted inside the machine body (1). A reset torsion spring (19) is installed on the outer periphery of one end of the adjusting shaft (9). One end of the reset torsion spring (19) abuts against the machine body (1), and the other end of the reset torsion spring (19) abuts against the needle pitch crank (10).
5. The thread-cutting, presser foot-lifting, and stitch length adjustment mechanism of the sewing machine according to claim 1, characterized in that: The wire cutting assembly (3) includes a wire cutting shaft (20) rotatably disposed in the body (1), one end of the wire cutting shaft (20) is connected to a scissor mechanism (21), and the other end of the wire cutting shaft (20) is equipped with a wire cutting transmission component (22) for being driven by the wire cutting crank (6).
6. The thread-cutting, presser foot-lifting, and stitch length adjustment mechanism of the sewing machine according to claim 5, characterized in that: The side of the wire cutting crank (6) is equipped with a wire cutting push column (23), and the wire cutting transmission component (22) is provided with a through hole (24) for the wire cutting push column (23) to move. The inner wall of the through hole (24) is provided with a working wall (25) for the wire cutting push column (23) to push.