Thread trimming mechanism of sewing machine and sewing machine thereof

Abstract

The utility model relates to sewing machine equipment, and discloses a thread trimming mechanism of a sewing machine and the sewing machine, the thread trimming mechanism comprises a motor, a thread trimming crank, a thread cutting tripod crank and a thread trimming assembly, the thread trimming crank is fastened on an output shaft of the motor, and an opening groove is formed in the thread trimming crank; a first rocker arm is arranged at one end of the tangent tripod crank, a rocker arm shaft on the first rocker arm extends into the open slot, and a second rocker arm is arranged at the other end of the tangent tripod crank; the thread trimming assembly comprises a scissor assembly and a reset element with the end abutting against the seat body, the second rocker arm is connected with the scissor assembly and drives the scissor assembly to trim threads, and the other end of the reset element is connected with the scissor assembly and enables the scissor assembly to reset after thread trimming. When the reset element loses efficacy and the cutter is stuck, the motor can drive the thread trimming crank to rotate and drive the thread cutting tripod crank to act, forced cutter return is achieved, sewing work interruption caused by cutter sticking is avoided, the use reliability of the sewing machine is improved, and the time cost and the labor cost caused by fault processing are reduced.

Description

Technical Field

[0001] This utility model relates to sewing machine equipment, and more particularly to a thread-cutting mechanism for a sewing machine and the sewing machine thereof. Background Technology

[0002] In the field of sewing equipment technology, the performance of the thread-cutting mechanism of a sewing machine is crucial to the quality and efficiency of sewing work. In existing technologies, such as the thread-cutting mechanism of a sewing machine disclosed in patent application number 202020682187.9, the thread-cutting drive is typically achieved using an electromagnet in conjunction with a cam. However, this technical solution, which triggers the thread-cutting action via an electromagnet, has significant drawbacks. Firstly, the electromagnet generates considerable noise during operation, affecting the working environment and potentially damaging the operator's hearing with prolonged exposure. Secondly, the thread-cutting effect is unstable, easily resulting in incomplete cutting and inconsistent thread lengths, thus impacting the quality of the sewn product.

[0003] Furthermore, the existing wire-cutting mechanism has a relatively complex structure, involving the precise coordination of multiple components, and requires high machining accuracy and assembly processes, which increases production costs and maintenance difficulty. Moreover, although some reset measures are in place to address wire-cutting failures such as tool jamming, the overall handling mechanism is not flexible or efficient enough, which may lead to prolonged equipment downtime and affect production efficiency.

[0004] Against this technological backdrop, a new thread-cutting mechanism for sewing machines has emerged. This new solution addresses issues in existing technologies, such as high noise levels, inconsistent thread-cutting performance, complex structures, and inflexible troubleshooting, aiming to provide a more efficient, stable, and easy-to-maintain thread-cutting mechanism. Utility Model Content

[0005] This utility model addresses the shortcomings of existing technologies by providing a thread-cutting mechanism for a sewing machine and a sewing machine thereof.

[0006] To solve the above-mentioned technical problems, the present invention provides a solution through the following technical method:

[0007] A thread-cutting mechanism for a sewing machine, comprising:

[0008] motor,

[0009] A wire-cutting crank is fastened to the output shaft of the motor, and the wire-cutting crank is provided with an opening slot.

[0010] A tangential tripod crank has a first rocker arm at one end, with the rocker arm shaft on the first rocker arm extending into an open slot, and a second rocker arm at the other end of the tangential tripod crank.

[0011] The wire cutting assembly includes a scissor assembly and a reset element whose end rests against the base. A second rocker arm is connected to the scissor assembly and drives it to cut the wire. The other end of the reset element is connected to the scissor assembly and resets it after cutting the wire.

[0012] Preferably, the wire cutting crank includes a sleeve portion and a wire cutting rocker arm. The wire cutting rocker arm is integrally formed on the side wall of the sleeve portion, and an opening groove is provided on the wire cutting rocker arm. The sleeve portion is fastened to the output shaft of the motor.

[0013] Preferably, a roller is mounted on the rocker arm shaft, and the roller extends into the opening groove.

[0014] Preferably, the first rocker arm and the second rocker arm are spatially offset, and the first rocker arm and the second rocker arm are not on the same plane.

[0015] Preferably, the wire cutting assembly also includes a wire cutting crank and a cutter drive crank shaft. The wire cutting crank is fastened to the scissor assembly, the cutter drive crank shaft is fastened to the wire cutting crank, a reset element is mounted on the cutter drive crank shaft, and the other end of the reset element abuts against the wire cutting crank. The second rocker arm is connected to the cutter drive crank shaft and drives it to rotate.

[0016] Preferably, the wire cutting assembly also includes a wire cutting bushing, which is fitted onto the cutter drive crankshaft, and a reset element is fitted onto the wire cutting bushing.

[0017] Preferably, the reset element is a torsion spring.

[0018] A sewing machine includes a base on which a thread-cutting mechanism is mounted.

[0019] This utility model, by adopting the above technical solution, has significant technical effects:

[0020] When the reset element fails and the blade jams, the motor can drive the thread cutting crank to rotate, which in turn drives the thread cutting triangle crank to force the blade back. This avoids the interruption of sewing work caused by the blade jam, improves the reliability of the sewing machine, and reduces the time and labor costs caused by troubleshooting. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model.

[0022] Figure 2 This is a magnified view of part A.

[0023] Figure 3 This is a magnified view of part B.

[0024] Figure 4 This is a schematic diagram of the second connector.

[0025] The names of the body parts referred to by the numbers in the above attached diagrams are as follows:

[0026] 10—Motor

[0027] 11—Wire cutting crank, 111—Opening groove, 112—Sleeve section, 113—Wire cutting rocker arm

[0028] 12—Tangential tripod crank, 121—First rocker arm, 122—Rocker arm shaft, 123—Second rocker arm, 124—Roller

[0029] 13—Scissors Components

[0030] 14—Reset Element

[0031] 15—Tangential Crank

[0032] 16—Cutter drive crankshaft

[0033] 17—Tangent shaft sleeve, 20—Seat body Detailed Implementation

[0034] The following is in conjunction with the appendix Figure 1-4 The present invention will be further described in detail with reference to the embodiments.

[0035] Example 1

[0036] A thread-cutting mechanism for a sewing machine, comprising:

[0037] Motor 10,

[0038] A wire-cutting crank 11 is fastened to the output shaft of the motor 10 by screws, and an opening slot 111 is provided on the wire-cutting crank 11.

[0039] A tangent triangle crank 12 is mounted on a base 20 via a pivot. The tangent triangle crank 12 can rotate on the pivot. One end of the tangent triangle crank 12 has a first rocker arm 121 integrally formed thereon. A rocker arm shaft 122 on the first rocker arm 121 extends into an opening slot 111, where the rocker arm shaft 122 is positioned. A motor 10 drives the tangent triangle crank 11 to rotate, which in turn moves the first rocker arm 121, thereby causing the tangent triangle crank 12 to rotate. The other end of the tangent triangle crank 12 has a second rocker arm 123 integrally formed thereon.

[0040] The wire cutting assembly includes a scissor assembly 13 and a reset element 14 whose end rests against the base 20. In this embodiment, the reset element 14 is a torsion spring. The reset element 14 provides torque so that the scissor assembly 13 can reset in time after cutting the wire. The second rocker arm 123 is connected to the scissor assembly 13 and drives it to cut the wire. When the second rocker arm 123 swings, it drives the scissor assembly 13 to cut the wire. The other end of the reset element 14 is connected to the scissor assembly 13 and resets it after cutting the wire.

[0041] Working principle: When wire cutting is required, the motor 10 starts, and its output shaft drives the wire cutting crank 11, which is fastened to it with screws, to rotate. Since the wire cutting crank 11 has an opening slot 111, and the rocker arm shaft 122 on the first rocker arm 121 at one end of the wire cutting tripod crank 12 extends into and is limited within the opening slot 111, the rotation of the wire cutting crank 11 drives the first rocker arm 121 to move, thereby causing the wire cutting tripod crank 12 to rotate around its mounting axis. The second rocker arm 123 at the other end of the wire cutting tripod crank 12 swings accordingly, and the scissor assembly 13 connected to the second rocker arm 123 is driven to perform the wire cutting action. After the wire cutting is completed, the reset element 14, whose end rests against the base 20, functions, using its own torque to drive the scissor assembly 13 to reset, preparing for the next wire cutting.

[0042] When a jam occurs due to abnormal conditions such as failure of the reset element 14, the connection between the motor 10 and the wire cutting crank 11 can be reversed by controlling the motor 10 to drive the wire cutting crank 11 to rotate in the opposite direction, which in turn drives the wire cutting triangle crank 12 to swing in the opposite direction, thereby releasing the scissor assembly 13 and achieving forced return of the blade. This can solve the jamming problem quickly and easily, reduce equipment downtime, and improve production efficiency.

[0043] By directly engaging the wire-cutting crank 11 with the tangent tripod crank 12, power transmission is achieved through a simple connection method using the open slot 111 and the rocker arm shaft 122. This reduces the complexity of the transmission structure, making the overall structure more compact, the transmission process simple and efficient, and lowering manufacturing and maintenance costs.

[0044] The wire-cutting crank 11 includes a sleeve portion 112 and a wire-cutting rocker arm 113. The wire-cutting rocker arm 113 is integrally formed on the side wall of the sleeve portion 112, and an opening slot 111 is provided on the wire-cutting rocker arm 113. The sleeve portion 112 is fastened to the output shaft of the motor 10. With the opening slot 111 on the wire-cutting rocker arm 113, when the motor 10 drives the sleeve portion 112 to rotate, the wire-cutting rocker arm 113 moves synchronously. The opening slot 111 cooperates with the rocker arm shaft 122 on the first rocker arm 121 of the tangent tripod crank 12, which can convert the circular motion of the motor 10 into the oscillation of the tangent tripod crank 12, achieving efficient power transmission and ensuring the smooth completion of the wire-cutting action. The stable structural design makes the wire-cutting crank 11 less prone to failure during long-term use. Even if the reset element 14 fails and causes the blade to jam, the reliable connection between the thread cutting crank 11 and the output shaft of the motor 10 allows the motor 10 to drive the thread cutting triangle crank 12 through the thread cutting crank 11 to achieve forced blade return, thus solving the blade jamming problem and improving the reliability and stability of the sewing machine's thread cutting mechanism.

[0045] The first rocker arm 121 and the second rocker arm 123 are spatially offset, meaning they are not on the same plane. This design allows for more efficient use of the limited space inside the sewing machine. This offset arrangement allows the various components of the thread-cutting mechanism to be arranged more compactly, avoiding the space congestion caused by components concentrated on the same plane. This contributes to the miniaturization and compact design of the overall sewing machine structure, while also providing more space and possibilities for the installation and layout of other components inside the sewing machine.

[0046] The thread-cutting assembly also includes a thread-cutting crank 15 and a cutter drive crank shaft 16. The thread-cutting crank 15 is fastened to the scissor assembly 13 by screws, and the cutter drive crank shaft 16 is fastened to the thread-cutting crank 15. The thread-cutting crank 15 is held tightly to the cutter drive crank shaft 16 through a notch. A reset element 14 is fitted onto the cutter drive crank shaft 16, with its other end abutting against the thread-cutting crank 15. A second rocker arm 123 is connected to and drives the cutter drive crank shaft 16 to rotate. The connection structure between the thread-cutting crank 15 and the cutter drive crank shaft 16 increases the overall rigidity and stability of the thread-cutting assembly. During the thread-cutting process, it can better resist external interference and vibration, reduce the shaking and offset of the scissor assembly 13, ensure the smoothness and consistency of the thread-cutting action, and thus improve the quality of sewing products.

[0047] The wire cutting assembly also includes a wire cutting sleeve 17, which is fitted onto the cutter drive crankshaft 16, and a reset element 14 is fitted onto the wire cutting sleeve 17. During operation, the reset element 14 undergoes continuous elastic deformation, and its direct contact with the cutter drive crankshaft 16 generates friction, easily causing wear. The wire cutting sleeve 17 acts as an intermediate medium, isolating the reset element 14 from the cutter drive crankshaft 16, ensuring that the friction of the reset element 14 mainly occurs on the contact surface with the wire cutting sleeve 17. By selecting a suitable material and surface treatment for the wire cutting sleeve 17, the coefficient of friction can be effectively reduced, decreasing the wear of the reset element 14 and extending its service life.

[0048] Example 2

[0049] Example 2 is essentially the same as Example 1, except that a roller 124 is mounted on the rocker arm shaft 122, extending into the opening groove 111. The lower friction means that the wear on the surfaces of the rocker arm shaft 122 and the opening groove 111 is significantly reduced. In long-term, frequent thread-cutting operations, this reduced wear extends the service life of the thread-cutting crank 11 and the thread-cutting tripod crank 12, reduces the frequency of parts replacement due to wear, decreases sewing machine maintenance costs and downtime, and improves production efficiency.

[0050] Example 3

[0051] A sewing machine includes a base 20 on which a thread-cutting mechanism of the sewing machine of embodiment 1 or 2 is mounted.

Claims

1. A thread trimming mechanism of a sewing machine, characterized by The utility model relates to a sewing machine's thread trimming mechanism, which comprises: a motor (10), a thread trimming crank (11) fastened on the output shaft of the motor (10), the thread trimming crank (11) being provided with an open slot (111); a thread cutting crank (12) provided at one end with a first swing arm (121), the swing arm shaft (122) of the first swing arm (121) extending into the open slot (111), the thread cutting crank (12) being provided at the other end with a second swing arm (123); a thread trimming assembly comprising a scissors assembly (13) and a reset element (14) abutting against the seat body (20), the second swing arm (123) being connected with the scissors assembly (13) and driving the scissors assembly (13) to trim the thread, the other end of the reset element (14) being connected with the scissors assembly (13) and resetting the scissors assembly (13) after trimming the thread.

2. A thread trimming mechanism for a sewing machine according to claim 1, characterized in that: The thread trimming crank (11) comprises a sleeve part (112) and a thread trimming swing arm (113), the thread trimming swing arm (113) being integrally formed on the side wall of the sleeve part (112), the open slot (111) being provided on the thread trimming swing arm (113), and the sleeve part (112) being fastened on the output shaft of the motor (10).

3. The thread trimming mechanism of claim 1 wherein: The swing arm shaft (122) is provided with a roller (124) extending into the open slot (111).

4. The thread trimming mechanism of claim 1 wherein: The first swing arm (121) and the second swing arm (123) are arranged in spatial dislocation, and the first swing arm (121) and the second swing arm (123) are not in the same plane.

5. The thread trimming mechanism of claim 1 wherein: The thread trimming assembly further comprises a thread cutting crank (15) fastened on the scissors assembly (13) and a thread cutting driving crank shaft (16) fastened on the thread cutting crank (15), the reset element (14) being sleeved on the thread cutting driving crank shaft (16), the other end of the reset element (14) abutting against the thread cutting crank (15), and the second swing arm (123) being connected with the thread cutting driving crank shaft (16) and driving the thread cutting driving crank shaft (16) to rotate.

6. A thread trimming mechanism for a sewing machine according to claim 5 wherein: The thread trimming assembly further comprises a thread cutting shaft sleeve (17) sleeved on the thread cutting driving crank shaft (16), and the reset element (14) being sleeved on the thread cutting shaft sleeve (17).

7. A thread trimming mechanism for a sewing machine according to any one of claims 1 to 6, characterized in that: The reset element (14) is a torsion spring.

8. Sewing machine comprising a seat (20), characterized in that: The seat body (20) is provided with the sewing machine's thread trimming mechanism according to any one of claims 1-7.

Images