Thread cutting device for a sewing machine

Abstract

The utility model provides a kind of thread cutting device for sewing machine, including sewing machine pedestal, thread cutting assembly and drive assembly, thread cutting assembly includes the thread cutting installation shaft being set on sewing machine pedestal, thread cutting knife rest is rotatably set in the front end of thread cutting installation shaft, drive assembly includes the drive installation shaft being set on sewing machine pedestal, motor is set on sewing machine pedestal, gear transmission mechanism connecting drive installation shaft and motor, connecting drive installation shaft and thread cutting knife rest's crank link mechanism.When using, motor drives drive installation shaft circumferential rotation by gear transmission mechanism, drive installation shaft drives thread cutting knife rest circumferential rotation shaft by crank link mechanism, to complete thread cutting.Motor is used as driving power, gear transmission mechanism and crank link mechanism are used to drive thread cutting knife rest rotation, so that the parts used in the above thread cutting device can be reduced, and the device has the advantage of not prone to failure.

Description

Technical Field

[0001] This utility model relates to sewing machines, and more particularly, to a thread cutting device for sewing machines. Background Technology

[0002] Currently, Chinese patent CN101709537B discloses a thread-cutting structure for a sewing machine, including a lower shaft, an electromagnet assembly, a cam actuation assembly, a thread-cutting assembly, a reset assembly, and a thread-releasing assembly. The electromagnet assembly consists of a mounting frame and an electromagnet vertically fixed to the mounting frame, with the actuating end of the electromagnet located at the lower part. The thread-cutting assembly includes a cutter connecting rod and a cutter holder connected by a short pin. The cam actuation assembly includes a thread-cutting cam, a thread-cutting roller, and a drive rod. The drive rod is horizontally positioned, with its active end hinged to the actuating end of the thread-cutting electromagnet via a spherical connecting pin. Its driven end is spherically connected to one end of the cutter connecting rod via a long spherical pin, and the other end of the cutter connecting rod is spherically connected to a short spherical pin. The thread-cutting roller is located at the active end of the drive rod. The thread-cutting cam is a cylindrical cam mechanism, fixedly mounted on the lower shaft, and the movement trajectory of the thread-cutting roller cooperates with the thread-cutting cam. The reset assembly includes a spring, which is located between the mounting frame and the active end of the drive rod. The wire release mechanism includes a wire release steel rope fixed to the active end of the drive rod, and the wire release steel rope is fixed to the drive rod by a steel rope pressure plate. In the above-described wire tangling structure, an electromagnet assembly is used as the driving force, and a cam-driven assembly is used to drive the cutter holder to rotate in order to complete the wire tangling. However, the cam-driven assembly uses many parts and is prone to failure. Summary of the Invention

[0003] In view of this, the purpose of this utility model is to provide a thread cutting device for a sewing machine, which has the advantages of reducing the number of parts used and being less prone to failure.

[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is: a thread cutting device for a sewing machine, including a sewing machine base, a thread cutting assembly, and a drive assembly. The thread cutting assembly includes a thread cutting mounting shaft disposed on the sewing machine base and a thread cutting blade holder rotatably sleeved on the front end of the thread cutting mounting shaft. The drive assembly includes a drive mounting shaft disposed on the sewing machine base, a motor disposed on the sewing machine base, a gear transmission mechanism connecting the drive mounting shaft and the motor, and a crank connecting rod mechanism connecting the drive mounting shaft and the thread cutting blade holder.

[0005] With the above technical solution, during use, the motor drives the drive mounting shaft to rotate circumferentially through a gear transmission mechanism. The drive mounting shaft, in turn, drives the tangent holder to rotate circumferentially through a crank-connecting rod mechanism, thus completing the cutting. By using the motor as the driving force and utilizing the gear transmission mechanism and crank-connecting rod mechanism to drive the tangent holder to rotate, the number of parts used in the above-mentioned cutting device can be reduced, giving it the advantage of being less prone to failure.

[0006] Preferably, the gear transmission mechanism includes a sector-shaped incomplete gear fixedly sleeved on the rear end of the drive mounting shaft and a drive gear fixedly sleeved on the motor output shaft, wherein the sector-shaped incomplete gear meshes with the drive gear.

[0007] Through the above technical solution, the incomplete gear, in conjunction with the driving gear, can drive the circumferential rotation of the drive mounting shaft with high transmission efficiency. Furthermore, the use of an incomplete gear ensures that even if the motor rotates too much, the tangent tool holder will not rotate excessively.

[0008] Preferably, the crank-connecting rod mechanism includes a transmission crank fixedly sleeved on the front end of the drive mounting shaft and a transmission connecting rod rotatably disposed at the end of the transmission crank, wherein the end of the transmission connecting rod away from the transmission crank is rotatably connected to the tangent holder.

[0009] Through the above technical solution, the transmission crank and the transmission connecting rod cooperate to drive the tangent tool holder to rotate circumferentially with high transmission efficiency.

[0010] Preferably, the sewing machine base includes two side plates symmetrically arranged on the left and right, and a horizontal plate vertically arranged between the two side plates. The tangent mounting shaft and the drive mounting shaft are both disposed through the horizontal plate. The tangent holder and the crank connecting rod mechanism are both disposed on the front side of the horizontal plate, and the motor and the gear transmission mechanism are both disposed on the rear side of the horizontal plate.

[0011] Through the above technical solution, the two side plates and the cross plate cooperate to form cavities on the front and rear sides. The front cavity can be used to house the tangent holder and the crank-connecting rod mechanism, while the rear cavity can be used to house the motor and the gear transmission mechanism. This arrangement can effectively reduce the volume of the tangent device, making its structure more compact.

[0012] Preferably, the drive assembly further includes a mounting bracket, which is pressed and fixed to the lower end of the two side plates by threaded parts, and the motor is fixedly mounted on the mounting bracket.

[0013] The above technical solution uses a mounting bracket to fix the motor to the sewing machine base, making the assembly and disassembly of the motor more convenient.

[0014] Preferably, the mounting bracket includes a mounting base plate, a connecting plate vertically disposed at the upper end of the mounting base plate, and a mounting plate abutting against the side wall of the connecting plate. A clearance through hole is provided through the mounting plate. The motor is fixedly disposed at the rear side wall of the mounting plate, and the output shaft of the motor passes through the clearance through hole.

[0015] The above technical solution consists of a mounting base plate, a connecting plate, and a mounting plate, which consumes less raw materials and has a lower production cost.

[0016] Preferably, the mounting plate has a vertical waist-shaped adjustment hole, and the mounting bracket also includes an adjustment screw. The head of the adjustment screw abuts against the mounting plate, and the threaded section of the adjustment screw passes through the waist-shaped adjustment hole and is threadedly connected to the connecting plate.

[0017] With the above technical solution, during use, only the adjusting screw needs to be rotated to control the mounting plate and the motor to slide along the extension direction of the waist-shaped adjusting hole, thereby changing the height of the motor.

[0018] Preferably, each of the two side plates has an installation notch at its lower front end, and the left and right ends of the mounting base plate are respectively abutted against the two installation notches.

[0019] The above technical solution uses an installation notch to locate the installation position of the mounting base plate, making the installation of the mounting bracket and motor more precise and convenient. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an embodiment;

[0021] Figure 2 This is a partial illustration of an embodiment. Figure 1 ;

[0022] Figure 3 This is a partial illustration of an embodiment. Figure 2 .

[0023] Reference numerals: 1. Sewing machine base; 11. Side plate; 12. Horizontal plate; 2. Thread cutting assembly; 21. Thread cutting mounting shaft; 22. Thread cutting blade holder; 3. Drive assembly; 31. Drive mounting shaft; 32. Motor; 33. Gear transmission mechanism; 331. Sector incomplete gear; 332. Drive gear; 34. Crank-connecting rod mechanism; 341. Transmission crank; 342. Transmission connecting rod; 35. Mounting bracket; 351. Mounting base plate; 352. Connecting upright plate; 353. Mounting upright plate; 4. Clearance through hole; 5. Waist-shaped adjustment hole; 6. Adjusting screw; 7. Mounting notch. Detailed Implementation

[0024] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, so that the technical solution of this utility model can be more easily understood and mastered.

[0025] A thread-cutting device for a sewing machine, such as Figures 1 to 3 As shown, it includes a sewing machine base 1, a thread cutting assembly 2, and a drive assembly 3.

[0026] The sewing machine base 1 includes two side plates 11 arranged symmetrically on the left and right, and a horizontal plate 12 arranged vertically between the two side plates 11. The lower front side of both side plates 11 is provided with an installation notch 7, and the height of the horizontal plate 12 is less than the height of the side plates 11.

[0027] The tangent assembly 2 includes a tangent mounting shaft 21 that passes through the horizontal plate 12 and a tangent knife holder 22 that is rotatably sleeved on the front end of the tangent mounting shaft 21. The tangent mounting shaft 21 extends back and forth in the horizontal direction, and the tangent knife holder 22 is located on the front side of the horizontal plate 12.

[0028] The drive assembly 3 includes a drive mounting shaft 31 that passes through the horizontal plate 12, a mounting bracket 35 that is mounted on the sewing machine base 1, a motor 32 that is mounted on the mounting bracket 35, a gear transmission mechanism 33 that connects the drive mounting shaft 31 and the motor 32, and a crank connecting rod mechanism 34 that connects the drive mounting shaft 31 and the tangent holder 22. The mounting bracket 35, the motor 32 and the gear transmission mechanism 33 are all located on the rear side of the horizontal plate 12, and the crank connecting rod mechanism 34 is located on the front side of the horizontal plate 12.

[0029] The drive mounting shaft 31 extends back and forth in the horizontal direction, and the height of the drive mounting shaft 31 is lower than the height of the tangential mounting shaft 21.

[0030] The mounting bracket 35 includes a mounting base plate 351, a connecting plate 352 vertically disposed on the upper end of the mounting base plate 351, and a mounting plate 353 abutting against the side wall of the connecting plate 352. The left and right ends of the mounting base plate 351 are respectively abutted against two mounting notches 7, and both ends of the mounting base plate 351 are pressed and fixed to the lower ends of the two side plates 11 by threaded fittings. In this embodiment, the threaded fittings are bolts. A clearance hole 4 is provided through the mounting plate 353, and the motor 32 is fixedly disposed on the rear side wall of the mounting plate 353, with the output shaft of the motor 32 passing through the clearance hole 4. A vertical oblong adjustment hole 5 is provided through the mounting plate 353. The mounting bracket 35 also includes an adjusting screw 6, the head of which abuts against the mounting plate 353, and the threaded section of the adjusting screw 6 passes through the oblong adjustment hole 5 and is threadedly connected to the connecting plate 352.

[0031] The gear transmission mechanism 33 includes a sector-shaped incomplete gear 331 fixedly sleeved on the rear end of the drive mounting shaft 31 and a drive gear 332 fixedly sleeved on the output shaft of the motor 32. The sector-shaped incomplete gear 331 meshes with the drive gear 332.

[0032] The crank-connecting rod mechanism 34 includes a transmission crank 341 fixedly sleeved on the front end of the drive mounting shaft 31 and a transmission connecting rod 342 rotatably disposed at the end of the transmission crank 341. The end of the transmission connecting rod 342 away from the transmission crank 341 is rotatably connected to the tangent holder 22.

[0033] Of course, the above are just typical examples of this utility model. In addition, this utility model may have many other specific implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by this utility model.

Claims

1. A thread-cutting device for a sewing machine, characterized in that: The sewing machine includes a sewing machine base (1), a thread cutting assembly (2), and a drive assembly (3). The thread cutting assembly (2) includes a thread cutting mounting shaft (21) mounted on the sewing machine base (1) and a thread cutting blade holder (22) rotatably sleeved on the front end of the thread cutting mounting shaft (21). The drive assembly (3) includes a drive mounting shaft (31) mounted on the sewing machine base (1), a motor (32) mounted on the sewing machine base (1), a gear transmission mechanism (33) connecting the drive mounting shaft (31) and the motor (32), and a crank-connecting rod mechanism (34) connecting the drive mounting shaft (31) and the thread cutting blade holder (22).

2. The thread-cutting device for a sewing machine according to claim 1, characterized in that: The gear transmission mechanism (33) includes a sector-shaped incomplete gear (331) fixedly sleeved on the rear end of the drive mounting shaft (31) and a drive gear (332) fixedly sleeved on the output shaft of the motor (32). The sector-shaped incomplete gear (331) meshes with the drive gear (332).

3. The thread-cutting device for a sewing machine according to claim 1, characterized in that: The crank-connecting rod mechanism (34) includes a transmission crank (341) fixedly sleeved on the front end of the drive mounting shaft (31) and a transmission connecting rod (342) rotatably disposed at the end of the transmission crank (341). The end of the transmission connecting rod (342) away from the transmission crank (341) is rotatably connected to the tangent holder (22).

4. A thread-cutting device for a sewing machine according to claim 1, characterized in that: The sewing machine base (1) includes two side plates (11) arranged symmetrically on the left and right, and a horizontal plate (12) arranged vertically between the two side plates (11). The tangent mounting shaft (21) and the drive mounting shaft (31) are both arranged through the horizontal plate (12). The tangent knife holder (22) and the crank connecting rod mechanism (34) are both arranged on the front side of the horizontal plate (12). The motor (32) and the gear transmission mechanism (33) are both arranged on the rear side of the horizontal plate (12).

5. A thread-cutting device for a sewing machine according to claim 4, characterized in that: The drive assembly (3) also includes a mounting bracket (35), which is fixed to the lower end of the two side plates (11) by threaded fasteners, and the motor (32) is fixedly mounted on the mounting bracket (35).

6. A thread-cutting device for a sewing machine according to claim 5, characterized in that: The mounting bracket (35) includes a mounting base plate (351), a connecting plate (352) vertically disposed on the upper end of the mounting base plate (351), and a mounting plate (353) closely disposed on the side wall of the connecting plate (352). A clearance through hole (4) is provided through the mounting plate (353). The motor (32) is fixedly disposed on the rear side wall of the mounting plate (353), and the output shaft of the motor (32) passes through the clearance through hole (4).

7. A thread-cutting device for a sewing machine according to claim 6, characterized in that: The mounting plate (353) is provided with a vertical waist-shaped adjustment hole (5). The mounting bracket (35) also includes an adjustment screw (6). The head of the adjustment screw (6) abuts against the mounting plate (353). The threaded section of the adjustment screw (6) passes through the waist-shaped adjustment hole (5) and is threadedly connected to the connecting plate (352).

8. A thread-cutting device for a sewing machine according to claim 6, characterized in that: The lower front side of both side plates (11) is provided with an installation notch (7), and the left and right ends of the mounting base plate (351) are respectively abutted in the two installation notches (7).

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