Thread trimming and presser foot lifting drive

Abstract

The application provides a thread trimming and presser foot lifting driving device arranged on a sewing machine, the sewing machine comprising a cutter assembly and a presser foot assembly, the thread trimming and presser foot lifting driving device comprising a driving motor, a special-shaped cam, a thread trimming transmission assembly and a presser foot lifting transmission assembly, the special-shaped cam being mounted on an output shaft of the driving motor, an outer circumferential surface of the special-shaped cam being divided into a first surface and a second surface, the first surface being outwardly convex compared with the second surface, an outer end surface of the special-shaped cam being divided into a third surface, a fourth surface and a fifth surface, the third surface being away from the driving motor compared with the fourth surface, the fifth surface being a transition surface between the third surface and the fourth surface, the presser foot lifting transmission assembly being connected with the presser foot assembly, and the thread trimming transmission assembly being connected with the cutter assembly. The thread trimming and presser foot lifting actions of the sewing machine can be realized by forward and reverse rotation of one driving motor, the action reaction is fast, and the transmission is stable and powerful.

Description

Technical Field

[0001] This invention relates to the field of sewing technology, and more particularly to a thread-cutting presser foot drive device. Background Technology

[0002] A typical overlock sewing machine requires thread cutting and presser foot lifting during operation. Multiple cylinders or electromagnets are usually installed on the overlock sewing machine to achieve the corresponding actions.

[0003] Pneumatic pressing foot lifting and wire cutting take a long time to execute the entire action, have a relatively slow response, and are quite noisy. Electromagnetic pressing foot lifting and wire cutting, on the other hand, have a short execution time, a fast response, and are quieter. However, under prolonged operation, the electromagnet is prone to overheating, resulting in slow and weak response when lifting the pressing foot and cutting the wire. Summary of the Invention

[0004] The purpose of this invention is to provide a wire-cutting and pressure-lifting foot drive device, which solves the problems of slow response and weak power in traditional wire-cutting and pressure-lifting foot drive devices.

[0005] To achieve the above objectives, the present invention provides a thread-cutting and presser foot lifting drive device, which is installed on a sewing machine. The sewing machine includes a cutter assembly and a presser foot assembly. The thread-cutting and presser foot lifting drive device includes a drive motor, a shaped cam, a thread-cutting transmission assembly, and a presser foot lifting transmission assembly. The shaped cam is mounted on the output shaft of the drive motor. The outer peripheral surface of the shaped cam is divided into a first surface and a second surface. The first surface protrudes outward relative to the second surface. The outer end surface of the shaped cam is divided into a third surface, a fourth surface, and a fifth surface. The third surface is farther away from the drive motor than the fourth surface. The fifth surface is a transition surface between the third surface and the fourth surface. The presser foot lifting transmission assembly is connected to the presser foot assembly, and the thread-cutting transmission assembly is connected to the cutter assembly.

[0006] When the drive motor rotates forward, it can drive the irregularly shaped cam to rotate and make the first surface abut against the lifting presser foot transmission assembly, thereby driving the lifting presser foot transmission assembly to move and driving the presser foot assembly to move, while the cutter assembly does not move.

[0007] When the drive motor reverses, it can drive the irregularly shaped cam to rotate and make the fifth surface abut against the wire cutting transmission assembly, thereby driving the wire cutting transmission assembly to move and driving the cutter assembly to move, while the presser foot assembly does not move.

[0008] Optionally, the presser foot lifting transmission assembly includes a presser foot plate, a first abutment block, and a presser shaft. One end of the presser foot plate is rotatably connected to one end of the presser shaft, and the other end is a free end. The first abutment block is disposed at one end of the presser shaft, and the other end of the presser shaft is connected to the presser foot assembly.

[0009] When the drive motor rotates forward, it can drive the irregularly shaped cam to rotate and make the first surface abut against the free end of the lifting foot plate, thereby driving the lifting foot plate to rotate relative to the lifting shaft and abut against the first abutment block, causing the first abutment block to rotate and drive the lifting shaft to rotate, thereby driving the lifting foot transmission assembly to operate.

[0010] Optionally, one end of the lifting foot plate has a first protrusion, and the first abutment has a second protrusion. When the lifting foot plate rotates at a first preset angle, the first protrusion abuts against the second protrusion.

[0011] Optionally, the first abutment is sleeved on the lifting shaft and its relative position to the lifting shaft is adjustable.

[0012] Optionally, a first return spring is provided on the lifting shaft, the first return spring being connected to the lifting foot plate and used to drive the lifting foot plate to return to its original position.

[0013] Optionally, the sewing machine includes an upper differential tooth assembly, and the thread-cutting presser foot drive device further includes an upper differential tooth transmission assembly. The upper differential tooth transmission assembly includes a tooth-lifting shaft and a second stop block. The tooth-lifting shaft is movably sleeved outside the presser foot shaft. One end of the presser foot plate is rotatably connected to one end of the tooth-lifting shaft. The second stop block is disposed at one end of the tooth-lifting shaft, and the other end of the tooth-lifting shaft is connected to the upper differential tooth assembly.

[0014] When the drive motor rotates forward, it can drive the irregular cam to rotate and make the first surface abut against the free end of the lifting foot plate, thereby driving the lifting foot plate to rotate relative to the tooth lifting shaft and abut against the second abutment block, so that the second abutment block rotates and drives the tooth lifting shaft to rotate, thereby driving the upper differential tooth assembly to move.

[0015] Optionally, one end of the lifting foot plate has a third protrusion, and the second abutment has a fourth protrusion. When the lifting foot plate rotates to a second preset angle, the third protrusion abuts against the fourth protrusion.

[0016] Optionally, the second abutment is sleeved on the tooth-lifting shaft and its relative position to the tooth-lifting shaft is adjustable.

[0017] Optionally, the thread cutting transmission assembly includes a thread cutting rocker arm, a connecting rod, and a connecting block. One end of the thread cutting rocker arm is rotatably connected to the body of the sewing machine, and the other end is rotatably connected to one end of the connecting rod. The other end of the connecting rod is rotatably connected to one end of the connecting block, and the other end of the connecting block is connected to the cutter assembly. A top block is provided on the thread cutting rocker arm.

[0018] When the drive motor reverses, it can drive the irregularly shaped cam to rotate and make the fifth surface abut against the top block, thereby driving the other end of the wire-cutting rocker to rotate and drive the connecting rod to rotate. The rotation of the connecting rod drives the connecting block to rotate, thereby driving the cutter assembly to move.

[0019] Optionally, a second return spring is provided on the machine body, the second return spring being connected to the wire-cutting rocker and used to drive the wire-cutting rocker to return to its original position.

[0020] The wire-cutting and pressure foot lifting drive device provided by the present invention has at least one of the following beneficial effects:

[0021] 1) The sewing machine can achieve the actions of thread cutting and presser foot lifting by the forward and reverse rotation of a single drive motor. It has a compact structure, low assembly and debugging requirements, and can effectively improve the overall production efficiency and reduce production costs.

[0022] 2) The action response is fast, the transmission is smooth and powerful, which reduces the load on the drive motor and ensures the stable operation of the drive motor;

[0023] 3) It also enables the lifting of differential teeth, simplifying the structure. Attached Figure Description

[0024] Those skilled in the art will understand that the accompanying drawings are provided to better understand the invention and do not constitute any limitation on the scope of the invention. Wherein:

[0025] Figure 1 This is a schematic diagram of the installation of the wire-cutting and pressure-foot-lifting drive device provided in an embodiment of the present invention;

[0026] Figure 2 This is a front view of the wire-cutting and pressure-foot-lifting drive device provided in an embodiment of the present invention;

[0027] Figure 3 This is a rear view of the wire-cutting and pressure-foot-lifting drive device provided in an embodiment of the present invention;

[0028] Figure 4 The left view of the irregularly shaped cam provided in an embodiment of the present invention;

[0029] Figure 5 The right view of the irregularly shaped cam provided in an embodiment of the present invention;

[0030] In the attached image:

[0031] 1-Drive motor; 2-Irregular cam; 3-Lifting pressure foot plate; 4-First stop block; 5-Lifting pressure shaft; 6-First return spring; 7-Lifting tooth shaft; 8-Second stop block; 9-Differential arm; 10-Differential tooth frame; 11-Upper differential tooth; 12-Pressure foot; 13-Wire cutting rocker arm; 14-Connecting rod; 15-Connecting block; 16-Top block; 17-Second return spring;

[0032] 21-First side; 22-Second side; 23-Third side; 24-Fourth side; 25-Fifth side; 31-First protrusion; 41-Second protrusion. Detailed Implementation

[0033] To make the objectives, advantages, and features of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to facilitate and clarify the explanation of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structures. In particular, different figures may emphasize different aspects and may sometimes use different scales.

[0034] As used herein, the singular forms “a,” “an,” and “the” include plural objects unless otherwise expressly indicated. As used herein, the term “or” is generally used to include “and / or” unless otherwise expressly indicated. As used herein, the term “a number” is generally used to include “at least one” unless otherwise expressly indicated. As used herein, the term “at least two” is generally used to include “two or more” unless otherwise expressly indicated. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature.

[0035] Please refer to Figures 1-5This embodiment provides a thread-cutting and presser foot lifting drive device, which is installed on a sewing machine. The sewing machine includes a cutter assembly and a presser foot assembly. The thread-cutting and presser foot lifting drive device includes a drive motor 1, a shaped cam 2, a thread-cutting transmission assembly, and a presser foot lifting transmission assembly. The shaped cam 2 is mounted on the output shaft of the drive motor 1. The outer peripheral surface of the shaped cam 2 is divided into a first surface 21 and a second surface 22. The first surface 21 protrudes outward relative to the second surface 22. The outer end surface of the shaped cam 2 is divided into a third surface 23, a fourth surface 24, and a fifth surface 25. The third surface 23 is farther away from the drive motor 1 than the fourth surface 24. The fifth surface 25 is a transition surface between the third surface 23 and the fourth surface 24. The presser foot lifting transmission assembly is connected to the presser foot assembly, and the thread-cutting transmission assembly is connected to the cutter assembly.

[0036] When the drive motor 1 rotates forward, it can drive the irregular cam 2 to rotate and make the first surface 21 abut against the lifting foot transmission assembly, thereby driving the lifting foot transmission assembly to move and driving the pressing foot assembly to move, while the cutting blade assembly does not move.

[0037] When the drive motor 1 reverses, it can drive the irregular cam 2 to rotate and make the fifth surface 25 abut against the wire cutting transmission assembly, thereby driving the wire cutting transmission assembly to move and driving the cutter assembly to move, while the presser foot assembly does not move.

[0038] It should be understood that the forward rotation and reverse rotation of drive motor 1 mentioned in this application are mainly for illustrative purposes to illustrate the technical concept of this application and are not intended to limit it.

[0039] Please refer to Figure 2 and combined Figures 4-5 The first surface 21 is a raised surface on the outer peripheral surface, which is essentially the working surface that drives the lifting foot assembly. The second surface 22 is a non-working surface. When the drive motor 1 reverses, the lifting foot plate rotates along the second surface 22, but does not contact the first surface 21 and the second surface 22. Therefore, the lifting foot transmission assembly and the pressing foot assembly do not move at this time.

[0040] Preferably, the first surface 21 and the second surface 22 have an arc-shaped gradual transition, which reduces the output torque of the drive motor 1 in driving the lifting foot assembly, thereby reducing energy consumption and improving the lifespan of the drive motor 1.

[0041] The outer end face of the irregular cam 2 is the end plane of the irregular cam 2 facing away from the drive motor 1. The third surface 23 is a convex surface on the outer end face, the fourth surface 24 is a flat surface that is concave relative to the third surface 23, and the fifth surface 25 is the transition surface between the third surface 23 and the fourth surface 24, which is actually an arc transition surface. Therefore, when the drive motor 1 rotates forward, the wire cutting drive assembly rotates along the fourth surface 24, but does not contact the entire outer end face. Thus, at this time, the wire cutting drive assembly and the cutter assembly do not operate.

[0042] It should be understood that in this embodiment, there are two transition surfaces between the third surface 23 and the fourth surface 24, but only one of them is used when the sewing machine is working.

[0043] For details, please refer to Figure 2 and Figure 3 The presser foot transmission assembly includes a presser foot plate 3, a first abutment block 4, and a presser shaft 5. One end of the presser foot plate 3 is rotatably connected to one end of the presser shaft 5, and the other end is a free end. The first abutment block 4 is disposed at one end of the presser shaft 5, and the other end of the presser shaft 5 is connected to the presser foot assembly.

[0044] When the drive motor 1 rotates forward, it can drive the irregular cam 2 to rotate, and make the first surface 21 abut against the free end of the lifting foot plate 3, thereby driving the lifting foot plate 3 to rotate relative to the lifting shaft 5 and abut against the first abutment 4, so that the first abutment 4 rotates and drives the lifting shaft 5 to rotate, thereby driving the lifting foot transmission assembly to move. At this time, the fourth surface 24 moves towards the wire cutting transmission assembly, but since there is a gap between the fourth surface 24 and the wire cutting transmission assembly, the fifth surface 25 does not contact the wire cutting transmission assembly, so the wire cutting transmission assembly does not move.

[0045] In this embodiment, one end of the lifting foot plate 3 has a first protrusion 31, and the first abutment 4 has a second protrusion 41. When the lifting foot plate 3 rotates at a first preset angle, the first protrusion 31 abuts against the second protrusion 41. That is, when the drive motor 1 rotates forward, it drives the lifting foot plate 3 to rotate. Before the first protrusion 31 abuts against the second protrusion 41, the lifting foot plate 3 rotates relative to the lifting shaft 5. At this time, the lifting shaft 5 and the first abutment 4 on it do not move. When the lifting foot plate 3 rotates to the point where the first protrusion 31 abuts against the second protrusion 41, the lifting foot plate 3 rotates and drives the first abutment 4 and the lifting shaft 5 to rotate together, thereby driving the subsequent presser foot assembly to move.

[0046] Preferably, the first abutment 4 is sleeved on the lifting shaft 5 and its relative position to the lifting shaft 5 is adjustable. This essentially allows for adjustment of the relative position between the first protrusion 31 and the second protrusion 41, thereby enabling adjustment of the pressing foot assembly's operating time and lifting height. In specific implementations, the mounting portion of the first abutment 4 can be designed as a clamp-like structure, securely fastened to the lifting shaft 5 using fasteners.

[0047] Preferably, a first return spring 6 is provided on the lifting shaft 5. The first return spring 6 is connected to the lifting foot plate 3 and is used to drive the lifting foot plate 3 to return to its original position. After the lifting foot action is completed, the drive motor 1 reverses, and the lifting foot plate 3 quickly returns to its original position under the action of the first return spring 6, improving work efficiency. In addition, by setting the first return spring 6, the lifting foot plate 3 is kept in contact with the irregular cam 2 (first surface 21 or second surface 22) at all times, reducing the noise of the whole machine operation. At the same time, it can also reduce the impact force and impact noise when the lifting foot plate 3 just contacts the first surface 21.

[0048] The sewing machine includes an upper differential tooth assembly, and the thread-cutting presser foot drive device further includes an upper differential tooth transmission assembly. The upper differential tooth transmission assembly includes a tooth-lifting shaft 7 and a second stop block 8. The tooth-lifting shaft 7 is movably sleeved outside the presser foot 5. One end of the presser foot plate 3 is rotatably connected to one end of the tooth-lifting shaft 7. The second stop block 8 is disposed at one end of the tooth-lifting shaft 7, and the other end of the tooth-lifting shaft 7 is connected to the upper differential tooth assembly.

[0049] When the drive motor 1 rotates forward, it can drive the irregular cam 2 to rotate and make the first surface 21 abut against the free end of the lifting foot plate 3, thereby driving the lifting foot plate 3 to rotate relative to the tooth lifting shaft 7 and abut against the second abutment block 8, so that the second abutment block 8 rotates and drives the tooth lifting shaft 7 to rotate, thereby driving the upper differential tooth assembly to move.

[0050] Please refer to Figure 3The upper differential tooth assembly (lifting upper differential tooth) is designed to solve the problem of fabric misalignment during sewing. Its structure typically includes a servo motor, a differential arm 9, a differential tooth frame 10, and an upper differential tooth 11. One end of the differential tooth frame 10 is connected to the servo motor, and the other end is connected to the upper differential tooth 11. One end of the differential arm 9 is connected to the lifting tooth shaft 7, and the other end is connected to the differential tooth frame 10. The bottom of the upper differential tooth 11 extends into the presser foot 12 and contacts the fabric to be sewn. Driven by the servo motor, the differential tooth frame 10 reciprocates, thus "pushing" the fabric forward along the sewing direction (similar to a duck paddling). This structure prevents misalignment, but the upper differential tooth 11 still needs to be lifted after sewing. This can be achieved by the drive motor 1 rotating forward, which drives the shaped cam 2 to rotate, causing the lifting tooth shaft 7 to rotate, thereby lifting the upper differential tooth 11 via the differential arm 9.

[0051] In this embodiment, one end of the lifting foot plate 3 has a third protrusion (not shown in the figure, but refer to the first protrusion 31), and the second abutment 8 has a fourth protrusion (not shown in the figure, but refer to the second protrusion 41). When the lifting foot plate 3 rotates to a second preset angle, the third protrusion abuts against the fourth protrusion. Preferably, the first protrusion 31 and the third protrusion on the lifting foot plate 3 are not adjacent to each other, but are arranged opposite each other on both sides of the end of the lifting foot plate 3. The second protrusion 41 on the first abutment 4 and the fourth protrusion on the second abutment 8 are also not adjacent to each other, but are arranged opposite each other (e.g., one on top and one on the bottom). When the lifting foot plate 3 rotates, the third protrusion on the lifting foot plate 3 first abuts against the fourth protrusion on the second abutment 8. That is, the second preset angle is smaller than the first preset angle, and the differential tooth 11 is lifted first. Then, as the drive motor 1 continues to rotate forward, the lifting foot plate 3 drives the tooth lifting shaft 7 to rotate relative to the lifting shaft 5. When the first protrusion 31 on the lifting foot plate 3 abuts against the second protrusion 41 on the first abutment 4, the lifting foot 12 is then lifted.

[0052] Preferably, the second abutment 8 is sleeved on the tooth-lifting shaft 7 and its relative position to the tooth-lifting shaft 7 is adjustable. This actually allows for adjustment of the relative position between the third protrusion and the fourth protrusion, thereby enabling adjustment of the action time and lifting height of the upper differential tooth 11 assembly. In specific implementation, the mounting portion of the second abutment 8 can be designed as a clamp-like form, tightly fixed to the tooth-lifting shaft 7 by fasteners.

[0053] Please continue to refer to Figure 2The thread cutting transmission assembly includes a thread cutting rocker arm 13, a connecting rod 14, and a connecting block 15. One end of the thread cutting rocker arm 13 is rotatably connected to the body of the sewing machine, and the other end is rotatably connected to one end of the connecting rod 14. The other end of the connecting rod 14 is rotatably connected to one end of the connecting block 15, and the other end of the connecting block 15 is connected to the cutter assembly. A top block 16 is provided on the thread cutting rocker arm 13.

[0054] When the drive motor 1 reverses, it can drive the irregular cam 2 to rotate and make the fifth surface 25 abut against the top block 16, thereby driving the other end of the wire cutting rocker 13 to rotate and drive the connecting rod 14 to rotate. The rotation of the connecting rod 14 drives the connecting block 15 to rotate, thereby driving the cutter assembly to move.

[0055] Preferably, a second return spring 17 is provided on the machine body. The second return spring 17 is connected to the wire-cutting rocker arm 13 and is used to drive the wire-cutting rocker arm 13 to return to its original position. After the wire-cutting action is completed, the drive motor 1 rotates forward, and the wire-cutting rocker arm 13 quickly returns to its original position under the action of the second return spring 17, improving work efficiency. In addition, by providing the second return spring 17, the wire-cutting rocker arm 13 is kept in contact with the irregular cam 2 (fourth surface 24 or fifth surface 25) at all times, reducing the noise of the entire machine operation. At the same time, it can also reduce the impact force and impact noise when the wire-cutting rocker arm 13 first contacts the fifth surface 25.

[0056] Preferably, a first bearing and a second bearing are rotatably mounted on the lifting foot plate 3 and the top block 16, respectively. The lifting foot plate 3 abuts against the first surface 21 of the irregular cam 2 via the first bearing, and the top block 16 abuts against the fifth surface 25 of the irregular cam 2 via the second bearing. Using bushings for connection effectively reduces wear and operating noise. Alternatively, a first axial screw and a second axial screw are fixedly mounted on the lifting foot plate 3 and the top block 16, respectively. A first bushing and a second bushing are rotatably fitted over the first axial screw and the second axial screw, respectively. The lifting foot plate 3 abuts against the first surface 21 of the irregular cam 2 via the first bushing, and the top block 16 abuts against the fifth surface 25 of the irregular cam 2 via the second bushing.

[0057] It should be understood that the cutter assembly, presser foot assembly and upper differential tooth assembly mentioned in this application are all conventional parts in existing sewing machines. This application has not made any improvements to them. Therefore, this application will not elaborate on the specific structure of the cutter assembly and the presser foot assembly.

[0058] In this embodiment, the driving motor is a stepper motor or a grating motor, which has high positioning accuracy and fast response, and will not have the phenomenon of weak lifting of the presser foot and weak wire cutting, which can effectively improve the overall production efficiency and reduce production costs.

[0059] In summary, the embodiments of the present invention provide a thread-cutting and presser foot lifting drive device, which can realize the actions of thread cutting, presser foot lifting, and differential tooth lifting of a sewing machine by the forward and reverse rotation of a drive motor. It has a compact structure, fast action response, and smooth and powerful transmission.

[0060] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A thread-cutting and presser foot lifting drive device, installed on a sewing machine, the sewing machine including a cutter assembly and a presser foot assembly, characterized in that, The wire-cutting and presser foot lifting drive device includes a drive motor, a shaped cam, a wire-cutting transmission assembly, and a presser foot lifting transmission assembly. The shaped cam is mounted on the output shaft of the drive motor. The outer peripheral surface of the shaped cam is divided into a first surface and a second surface. The first surface protrudes outward relative to the second surface. The outer end surface of the shaped cam is divided into a third surface, a fourth surface, and a fifth surface. The third surface is farther away from the drive motor than the fourth surface. The fifth surface is a transition surface between the third surface and the fourth surface. The presser foot lifting transmission assembly is connected to the presser foot assembly, and the wire-cutting transmission assembly is connected to the cutter assembly. When the drive motor rotates forward, it can drive the irregularly shaped cam to rotate and make the first surface abut against the lifting presser foot transmission assembly, thereby driving the lifting presser foot transmission assembly to move and driving the presser foot assembly to move, while the cutter assembly does not move. When the drive motor reverses, it can drive the irregularly shaped cam to rotate and make the fifth surface abut against the wire cutting transmission assembly, thereby driving the wire cutting transmission assembly to move and driving the cutter assembly to move, while the presser foot assembly does not move. The presser foot transmission assembly includes a presser foot plate, a first abutment block, and a presser shaft. One end of the presser foot plate is rotatably connected to one end of the presser shaft, and the other end is a free end. The first abutment block is disposed at one end of the presser shaft, and the other end of the presser shaft is connected to the presser foot assembly. When the drive motor rotates forward, it can drive the irregular cam to rotate and make the first surface abut against the free end of the lifting foot plate, thereby driving the lifting foot plate to rotate relative to the lifting shaft and abut against the first abutment, so that the first abutment rotates and drives the lifting shaft to rotate, thereby driving the lifting foot transmission assembly to operate. The wire-cutting pressure foot drive device also includes an upper differential tooth transmission assembly, which includes a tooth-lifting shaft and a second abutment. The tooth-lifting shaft is movably sleeved outside the pressure-lifting shaft. One end of the pressure-lifting foot plate is rotatably connected to one end of the tooth-lifting shaft. The second abutment is disposed at one end of the tooth-lifting shaft. The other end of the tooth-lifting shaft is connected to the upper differential tooth assembly. When the drive motor rotates forward, it can drive the irregular cam to rotate and make the first surface abut against the free end of the lifting foot plate, thereby driving the lifting foot plate to rotate relative to the tooth lifting shaft and abut against the second abutment, causing the second abutment to rotate and drive the tooth lifting shaft to rotate, thereby driving the upper differential tooth assembly to move. The lifting foot plate has a first protrusion at one end and a second protrusion on the first abutment. When the lifting foot plate rotates at a first preset angle, the first protrusion abuts against the second protrusion. The lifting foot plate also has a third protrusion at one end and a fourth protrusion on the second abutment. When the lifting foot plate rotates at a second preset angle, the third protrusion abuts against the fourth protrusion. The second preset angle is smaller than the first preset angle. When the lifting foot plate rotates, the third protrusion on the lifting foot plate first abuts against the fourth protrusion on the second abutment, performing the lifting differential tooth action first. Then, as the drive motor continues to rotate forward, the lifting foot plate drives the tooth lifting shaft to rotate relative to the lifting shaft. When the first protrusion on the lifting foot plate abuts against the second protrusion on the first abutment, the lifting foot action is performed again.

2. The wire-cutting and pressure-foot-lifting drive device as described in claim 1, characterized in that, The first abutment is sleeved on the lifting shaft and its relative position to the lifting shaft is adjustable.

3. The wire-cutting and pressure-foot-lifting drive device as described in claim 1, characterized in that, A first return spring is provided on the lifting shaft. The first return spring is connected to the lifting foot plate and is used to drive the lifting foot plate to return to its original position.

4. The wire-cutting and pressure-foot-lifting drive device as described in claim 1, characterized in that, The second abutment is sleeved on the tooth-lifting shaft and its relative position to the tooth-lifting shaft is adjustable.

5. The wire-cutting and pressure-foot-lifting drive device as described in claim 1, characterized in that, The thread cutting transmission assembly includes a thread cutting rocker arm, a connecting rod, and a connecting block. One end of the thread cutting rocker arm is rotatably connected to the body of the sewing machine, and the other end is rotatably connected to one end of the connecting rod. The other end of the connecting rod is rotatably connected to one end of the connecting block, and the other end of the connecting block is connected to the cutter assembly. A top block is provided on the thread cutting rocker arm. When the drive motor reverses, it can drive the irregularly shaped cam to rotate and make the fifth surface abut against the top block, thereby driving the other end of the wire-cutting rocker to rotate and drive the connecting rod to rotate. The rotation of the connecting rod drives the connecting block to rotate, thereby driving the cutter assembly to move.

6. The wire-cutting and pressure-foot-lifting drive device as described in claim 5, characterized in that, The machine body is provided with a second return spring, which is connected to the wire-cutting rocker and is used to drive the wire-cutting rocker to return to its original position.

Images