Crank sliding block thread trimming mechanism of sewing machine and sewing machine with crank sliding block thread trimming mechanism

Abstract

The utility model relates to sewing machine equipment, and discloses a crank sliding block thread trimming mechanism of a sewing machine and the sewing machine, the crank sliding block thread trimming mechanism comprises a motor, a thread trimming crank and a cutter driving crankshaft, the thread trimming crank is installed on an output shaft of the motor, and a sliding block is installed at the end of the thread trimming crank; a sliding groove is formed in the end portion of one end of the cutter driving crankshaft, the sliding block is matched with the sliding groove, and when the thread trimming crank drives the cutter driving crankshaft to rotate, the sliding block slides along the sliding groove; the other end of the cutter driving crankshaft is connected with the shear assembly in a fastening mode, and a reset element for driving the shear assembly to reset is installed on the cutter driving crankshaft. When the reset element loses efficacy and the cutter is stuck, the motor can drive the thread trimming crank to enable the sliding block to move reversely in the sliding groove, the cutter driving crank shaft is driven to rotate reversely, and forced cutter returning of the scissor assembly is achieved. Therefore, sewing work interruption, cloth damage or damage to other parts of the sewing machine due to cutter clamping are avoided, normal operation of the sewing machine is guaranteed, and economic loss of a user is reduced.

Description

Technical Field

[0001] This utility model relates to sewing machine equipment, and more particularly to a crank-slider 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 has a significant impact on the quality and efficiency of sewing work. Currently, the thread-cutting mechanism of a sewing machine disclosed in utility model patent application number 202020682187.9 and authorization announcement number CN 212426390U achieves the thread-cutting function through the coordinated operation of a motor, a thread-cutting drive component, a thread-cutting crank, a thread-cutting drive shaft, and a cutting blade assembly. This technical solution effectively improves the problems of high noise and unstable thread-cutting effect when using a traditional electromagnet and cam for thread cutting.

[0003] However, this existing technology still has some drawbacks. First, its structure is relatively complex, containing multiple connecting rods, cranks, and various connecting components. This increases the difficulty and cost of manufacturing, and makes installation and debugging more cumbersome, requiring a higher level of expertise from technicians. Second, during long-term use, the frequent relative movements of the components cause them to wear easily. For example, the hinge points between the thread-cutting connecting rod and other components in the transmission assembly, as well as the contact points between the thread-cutting drive crank and the thread-cutting crank, will affect the accuracy and stability of the thread-cutting mechanism after wear, leading to a decrease in thread-cutting effect, and even problems such as incomplete thread cutting and thread residue. Third, the existing technology includes a reset component, such as a reset torsion spring sleeved on the bushing, used to drive the cutter assembly to reset. However, when the reset element fails, the cutter is prone to jamming. Once the cutter jams, it will not only interrupt the sewing work, but may also damage the fabric or other parts of the sewing machine, causing considerable inconvenience and economic losses to the user. Utility Model Content

[0004] This utility model addresses the shortcomings of existing technologies by providing a crank-slider thread-cutting mechanism for a sewing machine and the sewing machine thereof.

[0005] To solve the above-mentioned technical problems, the present invention provides a solution through the following technical method:

[0006] A crank-slider thread-cutting mechanism for a sewing machine, comprising:

[0007] motor,

[0008] A wire-cutting crank is mounted on the output shaft of the motor, and a slider is installed at the end of the wire-cutting crank.

[0009] The cutter drives the crankshaft, and a groove is provided at one end of the cutter drives the crankshaft. The slider is adapted to the groove. When the wire cutting crank drives the cutter drives the crankshaft to rotate, the slider slides along the groove.

[0010] The other end of the cutter drive crankshaft is fastened to the scissor assembly, and a reset element is installed on the cutter drive crankshaft to drive the scissor assembly to reset.

[0011] Preferably, the wire-cutting crank includes a mounting part and a crank arm. The mounting part is locked to the output shaft of the motor by fasteners. The crank arm is integrally formed with the mounting part and extends outward. A pin is fixed to the end of the crank arm, and a slider is fitted onto the pin and can rotate around it.

[0012] Preferably, the slider has a square shape when projected axially.

[0013] Preferably, the end of the cutter drive crankshaft is provided with an outwardly extending guide plate, and a groove is provided on the guide plate.

[0014] Preferably, extension plates are provided on both sides of the opening end of the chute. The extension plates are integrally formed on the guide plate, and a channel communicating with the chute is formed between the two extension plates. The channel and the chute form a long groove.

[0015] Preferably, a tangential crank is fixedly attached to one side of the scissor assembly, and the other end of the cutter drive crank shaft is fixedly attached to the tangential crank.

[0016] Preferably, the device also includes a base, and the reset element is a torsion spring. The reset element is mounted on the cutter drive crank shaft, with one end of the reset element pressing against the tangential crank and the other end pressing against the base.

[0017] Preferably, a bushing is fitted on the cutter drive crankshaft, and a reset element is fitted on the bushing.

[0018] A sewing machine, including a crank-slider thread-cutting mechanism for a sewing machine.

[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, causing the slider to move in the opposite direction within the groove. This, in turn, drives the cutter's crank shaft to reverse, forcing the scissor assembly to return to its original position. This prevents sewing work interruptions, fabric damage, or damage to other parts of the sewing machine caused by blade jamming, ensuring the normal operation of the sewing machine and reducing economic losses for the user. Attached Figure Description

[0021] Figure 1 This is a structural diagram of the present invention without the mounting base.

[0022] Figure 2 This is a schematic diagram of the wire shear crank.

[0023] Figure 3 This is a schematic diagram of the first structure of the cutter-driven crankshaft.

[0024] Figure 4 This is a schematic diagram of the second structure of the cutter-driven crankshaft.

[0025] Figure 5 This is a schematic diagram of the structure of this utility model with the base installed.

[0026] The names of the body parts referred to by the numbers in the above attached diagrams are as follows:

[0027] 1—Motor

[0028] 2—Wire cutting crank, 21—Slider, 22—Mounting part, 23—Crank arm, 24—Pin shaft

[0029] 3—Cutter drive crankshaft, 31—Slide groove, 32—Guide plate, 33—Extension plate, 34—Channel, 35—Long groove

[0030] 4—Scissors assembly

[0031] 5—Reset element

[0032] 6—Tangential Crank

[0033] 7—Body

[0034] 8—Sleeve Detailed Implementation

[0035] The following is in conjunction with the appendix Figure 1-5 The present invention will be further described in detail with reference to the embodiments.

[0036] Example 1

[0037] A crank-slider thread-cutting mechanism for a sewing machine, comprising:

[0038] Motor 1,

[0039] A wire-cutting crank 2 is mounted on the output shaft of the motor 1, and a slider 21 is mounted on the end of the wire-cutting crank 2.

[0040] The cutter drive crankshaft 3 has a groove 31 at one end. The slider 21 is adapted to the groove 31. When the wire cutting crank 2 drives the cutter drive crankshaft 3 to rotate, the slider 21 slides along the groove 31.

[0041] The other end of the cutter drive crankshaft 3 is fastened to the scissor assembly 4. The rotation of the cutter drive crankshaft 3 will drive the scissor assembly 4 to perform the cutting action. A reset element 5 is installed on the cutter drive crankshaft 3 to drive the scissor assembly 4 to reset. After the scissor assembly 4 has finished cutting the thread, the reset element 5 can drive the scissor assembly 4 to reset.

[0042] When the sewing machine needs to cut the thread, motor 1 starts running, driving the thread-cutting crank 2 mounted on its output shaft to rotate. During the rotation of the thread-cutting crank 2, the slider 21 at the end of the thread-cutting crank 2 slides along the groove 31 at one end of the cutter drive crank shaft 3. Due to the cooperation between the slider 21 and the groove 31, this sliding drives the cutter drive crank shaft 3 to rotate. The other end of the cutter drive crank shaft 3 is securely connected to the scissor assembly 4, so the rotation of the cutter drive crank shaft 3 drives the scissor assembly 4 to move, thus realizing the thread-cutting operation. After the thread cutting is completed, the reset element 5 mounted on the cutter drive crank shaft 3 functions, driving the scissor assembly 4 to reset, preparing for the next thread cutting.

[0043] When the reset element 5 fails and a jamming occurs, due to the connection between the motor 1 and the entire transmission structure, the motor 1 can be reversed, causing the thread-cutting crank 2 to rotate in the opposite direction. This, in turn, drives the slider 21 to slide in the opposite direction within the groove 31, ultimately causing the cutter to drive the crank shaft 3 to rotate in the opposite direction, thus forcibly returning the scissor assembly 4 to its original position. This forced return function effectively avoids sewing work interruptions, fabric damage, and damage to other parts of the sewing machine caused by a jammed blade, ensuring the normal operation of the sewing machine and reducing maintenance costs and production losses.

[0044] The wire-cutting crank 2 includes a mounting part 22 and a crank arm 23. The mounting part 22 is locked onto the output shaft of the motor 1 by fasteners, which are screws. The crank arm 23 is integrally formed with the mounting part 22 and extends outward. A pin 24 is fixed to the end of the crank arm 23, and a slider 21 is fitted onto the pin 24 and can rotate around it. The integral formation of the crank arm 23 and the mounting part 22 eliminates potential weak points at the joint, improves the overall structural strength of the wire-cutting crank 2, and makes it less prone to deformation or damage when bearing the torque transmitted by the motor 1 and the reaction force during the wire-cutting process, thus extending the service life of the wire-cutting crank 2. The pin 24 is fixed to the end of the crank arm 23, and the slider 21 is fitted onto the pin 24 and can rotate around it. This design allows the slider 21 to slide more flexibly when it engages with the groove 31 of the cutter drive crank shaft 3. This reduces frictional resistance during movement, improves the transmission efficiency of the entire wire-cutting mechanism, and ensures the smoothness of the wire-cutting action.

[0045] Under the axial projection, the slider 21 has a square shape, which makes it easier for the slider 21 to mate with the groove 31 of the cutter drive crankshaft 3. Its regular shape allows technicians to quickly and accurately place the slider 21 into the groove 31 during installation without complicated calibration and adjustment, greatly shortening the installation time and improving assembly efficiency.

[0046] The end of the cutter drive crankshaft 3 is provided with an outwardly extending guide plate 32, and a groove 31 is provided on the guide plate 32. Positioning the groove 31 on the outwardly extending guide plate 32 makes its position more prominent and independent. During assembly, it is easier to align the slider 21 with the groove 31, reducing installation difficulty and improving assembly efficiency. It also facilitates later maintenance and repair of the groove 31 and slider 21. The guide plate 32, as an independent component, supports the groove 31, thus sharing the wear of the cutter drive crankshaft 3 during sliding. When friction occurs between the slider 21 and the groove 31, the guide plate 32 bears the brunt, reducing the direct wear on the cutter drive crankshaft 3, extending its service life, and lowering maintenance costs. Meanwhile, since the length of the groove 31 is slightly longer than the thickness of the slider 21, the slider 21 of the wire cutting crank 2 can be disengaged from the groove 31 on the cutter drive crank shaft 3 without the need to disassemble other parts, thus facilitating the disassembly and assembly of the wire cutting crank 2.

[0047] A tangent crank 6 is fastened to one side of the scissor assembly 4, and the other end of the cutter drive crank shaft 3 is fastened to the tangent crank 6. The tangent crank 6 has a notch channel, and the cutter drive crank shaft 3 is installed within this notch channel. When the bolts tighten the notch channel, the notch spacing decreases, thus locking the cutter drive crank shaft 3. The tangent crank 6 provides a stable fastening point for the cutter drive crank shaft 3 and also provides an ideal contact position for the reset element. This ideal contact position allows the reset element to act more effectively on the tangent crank 6, thereby driving the cutter drive crank shaft 3 and the scissor assembly 4 to reset. A reasonable contact position optimizes the working effect of the reset element, ensuring that the scissor assembly 4 can quickly and accurately return to its initial position after cutting the wire, preparing for the next cutting operation and improving the efficiency and reliability of the wire cutting mechanism.

[0048] The crank-slider thread-cutting mechanism also includes a base 7 and a torsion spring 5 as the reset element. The reset element 5 is mounted on the cutter drive crank shaft 3, with one end pressing against the thread-cutting crank 6 and the other end pressing against the base 7. By using a torsion spring as the reset element 5, mounted on the cutter drive crank shaft 3 and with one end pressing between the thread-cutting crank 6 and the base 7, the elastic properties of the torsion spring allow it to quickly release its force after the thread-cutting action is completed. This drives the thread-cutting crank 6 to reverse the cutter drive crank shaft 3, causing the scissor assembly 4 to quickly reset, ensuring the continuity of the thread-cutting operation and improving the working efficiency of the sewing machine.

[0049] A bushing 8 is fitted onto the cutter drive crankshaft 3, and a reset element 5 is fitted onto the bushing 8. The bushing 8 forms an isolation layer between the reset element 5 and the cutter drive crankshaft 3. During operation, the reset element 5 continuously expands, contracts, and twists, generating friction with the shaft. The bushing 8 can withstand this friction, preventing the reset element 5 from directly wearing down the cutter drive crankshaft 3, thereby extending the service life of the cutter drive crankshaft 3 and reducing equipment maintenance costs.

[0050] Example 2

[0051] Example 2 is basically the same as Example 1, except that extension plates 33 are provided on both sides of the opening end of the slide groove 31. The extension plates 33 are integrally formed on the guide plate 32. The two extension plates 33 are parallel to each other, and a channel 34 communicating with the slide groove 31 is formed between the two extension plates 33. The inner wall of the channel 34 is flush with the inner wall of the slide groove 31. The channel 34 and the slide groove 31 form a long groove 35. The slider 21 slides relative to each other in the long groove 35. The slider 21 will not easily disengage from the long groove 35, that is, the wire cutting crank 2 can be stably connected with the cutter drive crank shaft 3. When the reset element 5 fails, the motor 1 reverses and drives the wire cutting crank 2 to rotate. The wire cutting crank 2 can stably drive the cutter drive crank shaft 3 to rotate, thereby realizing the stable and timely return reset of the scissor assembly 4.

[0052] Example 3

[0053] A sewing machine, including a crank-slider thread-cutting mechanism of one of the sewing machines in Embodiment 1 or 2.

Claims

1. A crank slider thread trimming mechanism for a sewing machine, characterized by It comprises: a motor (1), a thread cutting crank (2) mounted on the output shaft of the motor (1), the end of the thread cutting crank (2) being provided with a sliding block (21); a cutter driving crank shaft (3), the end of the cutter driving crank shaft (3) being provided with a sliding groove (31), the sliding block (21) being adapted to the sliding groove (31), when the thread cutting crank (2) drives the cutter driving crank shaft (3) to rotate, the sliding block (21) slides along the sliding groove (31); the other end of the cutter driving crank shaft (3) being fastened to a cutter assembly (4), the cutter driving crank shaft (3) being provided with a reset element (5) for driving the cutter assembly (4) to reset.

2. A crank slider thread trimming mechanism for a sewing machine according to claim 1, characterized in that: The thread cutting crank (2) comprises a mounting portion (22) and a crank arm (23), the mounting portion (22) being locked on the output shaft of the motor (1) by fasteners, the crank arm (23) being integrally formed with the mounting portion (22) and extending outward, the end of the crank arm (23) being fixed with a pin shaft (24), the sliding block (21) being sleeved on the pin shaft (24) and being rotatable thereon.

3. A crank slider thread trimming mechanism for a sewing machine as defined in claim 2, wherein: The sliding block (21) is square in shape in the axial projection.

4. The crank slider thread-trimming mechanism of a sewing machine according to claim 1, characterized in that: The end of the cutter driving crank shaft (3) is provided with an outwardly extending guide plate (32), the sliding groove (31) being provided on the guide plate (32).

5. A crank slider thread trimming mechanism for a sewing machine as defined in claim 4 wherein: Both sides of the opening end of the sliding groove (31) are provided with extension plates (33), the extension plates (33) being integrally formed on the guide plate (32), a channel (34) being formed between the two extension plates (33) and being in communication with the sliding groove (31), the channel (34) and the sliding groove (31) forming an elongated groove (35).

6. A crank slider thread trimming mechanism for a sewing machine as defined in claim 1, wherein: The cutter assembly (4) is fastened with a thread cutting crank (6) on one side, the other end of the cutter driving crank shaft (3) being fastened to the thread cutting crank (6).

7. A crank slider thread trimming mechanism for a sewing machine as defined in claim 6 wherein: It further comprises a seat body (7), the reset element (5) being a torsion spring, the reset element (5) being sleeved on the cutter driving crank shaft (3), one end of the reset element (5) being abutted against the thread cutting crank (6), the other end of the reset element (5) being abutted against the seat body (7).

8. A crank slider thread trimming mechanism for a sewing machine according to any one of claims 1 to 7, characterized in that: A shaft sleeve (8) is sleeved on the cutter driving crank shaft (3), the reset element (5) being sleeved on the shaft sleeve (8).

9. Sewing machine, characterized in that: A crank sliding block thread cutting mechanism of a sewing machine according to any one of claims 1-8.

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