CN215887452U - Sewing machine - Google Patents

Abstract

The application provides a sewing machine, wherein a swing crank is fixedly installed on a cloth feeding motor output shaft connected through a cloth feeding motor, the swing crank is hinged with a connecting rod, the connecting rod is hinged with a cloth feeding shaft crank, the cloth feeding shaft crank is fixed on the rear end of a cloth feeding shaft, the front end of the cloth feeding shaft is connected with a cloth feeding tooth holder, the cloth feeding tooth holder is connected with a cloth feeding tooth frame, and the cloth feeding tooth is fixed on the cloth feeding tooth frame; the feed dog of the sewing machine is driven by the feed motor and the feed dog driving source together to realize sewing work under the control of the control system. The swing seat has the advantages that the traditional cloth feeding connecting rod, the traditional tooth lifting connecting rod and the cam on the main shaft are omitted, so that the tooth lifting amplitude of the cloth feeding teeth is controlled by the control system, meanwhile, the traditional part of the swing seat is eliminated, the functions of the swing seat can be completely realized, and the swing seat has higher popularization and use values.

Description

Sewing machine

Technical Field

The application provides a sewing machine, concretely relates to sewing machine makes technical field.

Background

In the driving mechanism of the sewing machine, a main motor is arranged on a machine head of the sewing machine and is connected with an output main shaft, an eccentric wheel is fixedly arranged on the output main shaft, and the main motor rotates to drive a cloth feeding connecting rod and a feed lifting connecting rod to move. The cloth feeding connecting rod drives the cloth feeding shaft to rotate at a certain angle through the swinging seat component, and the feed lifting connecting rod drives the feed lifting rock shaft to swing at a certain angle through the feed lifting rock crank; the swing of the cloth feeding connecting rod and the cloth feeding shaft drives the cloth feeding tooth rack to swing so as to generate back-and-forth motion for the cloth feeding tooth; the feed dog connecting rod and the feed dog shaft swing to drive the feed dog fork on the feed dog shaft to swing so as to enable the feed dog to move up and down, and the forward and backward movement and the up and down movement are combined to form the feed action of the feed dog.

Aiming at a swinging seat for controlling the needle pitch, a plurality of enterprises put forward an intelligent control technical scheme for realizing the cloth feeding needle pitch. The cloth feeding device is characterized by further comprising a swing rod, the cloth feeding shaft driving source is provided with an output shaft, the swing rod is mounted on the output shaft, the swing rod is connected with the crank through a hinge, the connecting crank is fixed on the cloth feeding shaft, the cloth feeding shaft is movably connected with the cloth feeding tooth rack, and the cloth feeding tooth rack is fixedly provided with the cloth feeding tooth. In fact, the proposal utilizes the cloth feeding shaft driving source to drive the swing rod to replace a cloth feeding connecting rod of the original sewing machine, carries out the stitch length adjustment on the stitch length adjusting mechanism and positions the zero point position of the cloth feeding teeth on the zero position positioning mechanism, and achieves the positive stitch length adjusting technical effect. However, the movement of the feed lifting connecting rod still remains in the prior art, so that the cloth feeding action of the feed dog cannot reach the intelligent control level.

Disclosure of Invention

Aiming at the defects of complex structure, low intelligent control level and the like of the sewing machine, the application provides the sewing machine without a swing seat and simple structure, which aims to solve at least one problem, and the sewing machine is provided with a cloth feeding shaft and a feed lifting shaft, wherein the cloth feeding shaft and the feed lifting shaft are indirectly connected with a cloth feeding tooth; the feed lifting tooth driving source is connected with a feed lifting tooth shaft, the other end of the feed lifting tooth shaft is connected with a feed lifting tooth fork-shaped crank, and the feed lifting tooth fork-shaped crank is matched with a movable shaft of the feed feeding tooth frame.

Preferably, a cloth feeding motor output shaft of the cloth feeding motor is fixed on the cloth feeding shaft crank.

Preferably, the feed dog driving source is mounted and fixed on a base plate of the sewing machine, and the feed dog driving source uses a motor.

Preferably, the feed lifting driving source and the feed lifting shaft are connected by a coupling.

Preferably, a first crank is mounted on an output shaft of the feed lifting teeth driving source, a second crank is mounted and connected on one side, close to the feed lifting teeth driving source, of the feed lifting teeth shaft, and the first crank is hinged to the second crank through a first connecting rod.

Preferably, the cloth feeding motor is fixedly installed on a machine body on the side edge of the sewing machine, and an output shaft of the cloth feeding motor connected with the cloth feeding motor penetrates through the machine body.

Preferably, the cloth feeding motor operates in a repeated back-and-forth swinging mode under the control of the control system, so that the swinging crank generates repeated swinging motion, and the swinging crank indirectly transmits the repeated swinging motion to the cloth feeding teeth, so that the cloth feeding teeth have back-and-forth cloth feeding motion.

Preferably, the feed dog driving source operates in a repeated back-and-forth swinging mode under the control of the control system, so that the feed dog shaft and the feed dog forked crank generate repeated swinging motion, and the feed dog shaft transmits the repeated swinging motion to the feed dog through the feed dog frame, so that the feed dog has up-and-down feed motion.

Preferably, the sewing machine is also provided with a presser foot lifting assembly and a thread trimming assembly, the presser foot lifting assembly is provided with a thread trimming and presser foot lifting motor, a presser foot lifting cam, a presser foot lifting ejector rod and a presser foot lifting execution end, the presser foot lifting cam is provided with a presser foot lifting cam lifting surface and an idle circular arc surface, the presser foot lifting cam is fixed on an output shaft of the thread trimming and presser foot lifting motor, the presser foot lifting cam lifting surface is used for adjusting the presser foot lifting ejector rod to be at a higher or lower position at a lower or higher position, the idle circular arc surface is used for idle rotation between the presser foot lifting ejector rod and the presser foot lifting cam, the idle circular arc surface and the output shaft of the thread trimming and presser foot lifting motor are arranged concentrically, and the presser foot lifting cam lifting surface is positioned at a cam part of the presser foot lifting cam;

the thread trimming component is provided with a thread trimming and presser foot lifting motor, a thread trimming crank, a thread trimming fork wheel and a thread trimming execution end, the thread trimming crank is provided with a pushing piece, the pushing piece is arranged at the eccentric position of the thread trimming crank and pushes the thread trimming fork wheel to perform thread trimming action, the thread trimming fork wheel is provided with a return rod and a thread trimming rod, the pushing piece is positioned between the return rod and the thread trimming rod, and the pushing piece pushes the thread trimming rod to enable the thread trimming execution end to execute the thread trimming action under the condition that the thread trimming and presser foot lifting motor drives the thread trimming crank;

after the thread trimming action is finished, the presser foot lifting cam starts to perform the presser foot lifting action, the rotation angle of the thread trimming and presser foot lifting motor does not enable the presser foot lifting cam to generate actual presser foot lifting action on the presser foot lifting ejector rod during the thread trimming action, the presser foot lifting ejector rod and the idle circular arc surface are in idle rotation, the thread trimming and presser foot lifting motor drives the presser foot lifting cam lifting surface of the presser foot lifting cam to lift the presser foot lifting ejector rod, the presser foot lifting ejector rod is lifted to the highest point when the highest point of the presser foot lifting ejector rod is reached, and the presser foot lifting execution end completes the presser foot lifting action;

in the presser foot lifting process, the pushing piece pushes the return rod, so that the pushing piece pushes the return rod to the original position, the whole thread cutting assembly is reset, the thread cutting assembly can be effectively and directly returned to the original position in the fault state of clamping, and the resetting function is realized;

when the presser foot is to be lowered, the trimming and presser foot lifting motor returns the presser foot lifting ejector rod to the idle running arc surface from the presser foot lifting cam lifting surface under the action of the clockwise force, so that the action of lowering the presser foot is realized.

Compared with the prior art, the beneficial effects of this application are: a swing crank is fixedly arranged on an output shaft of a cloth feeding motor connected through the cloth feeding motor, the swing crank is hinged with a connecting rod, the connecting rod is hinged with a cloth feeding shaft crank, the cloth feeding shaft crank is fixed on the rear end of a cloth feeding shaft, the front end of the cloth feeding shaft is connected with a cloth feeding tooth holder, the cloth feeding tooth holder is connected with a cloth feeding tooth frame, and the cloth feeding tooth is fixed on the cloth feeding tooth frame; the feed dog of the sewing machine is driven by the feed motor and the feed dog driving source together to realize sewing work under the control of the control system. The sewing machine breaks through the traditional technical scheme, cancels the traditional cloth feeding connecting rod, the feed lifting tooth connecting rod and the cam on the main shaft, can shorten the length of the feed lifting tooth shaft to reduce the manufacturing cost, enables the feed lifting tooth amplitude of the feed lifting tooth to be controlled by the control system, further improves the intelligent level of sewing, and simultaneously points out that the traditional part of the swinging seat is removed, but the sewing machine can completely have the functions of the swinging seat, and has higher popularization and use values.

Drawings

FIG. 1 is a schematic view of a drive mechanism of a sewing machine;

FIG. 2 is a schematic view showing a feed dog driving mechanism of a sewing machine;

FIG. 3 is a schematic view of a thread trimming and presser foot lifting mechanism of the sewing machine;

FIG. 4 is a schematic view showing a thread trimming mechanism of the sewing machine;

FIG. 5 is a schematic view of a presser foot lifting sheave and a presser foot lifting ram of a sewing machine;

FIG. 6 is a schematic view showing a second embodiment of a sewing machine;

FIG. 7 is a schematic view showing a third embodiment of a sewing machine.

Marking: the cloth feeding device comprises a cloth feeding motor 11, a cloth feeding motor output shaft 12, a swinging crank 13, a connecting rod 14, a cloth feeding shaft crank 15, a cloth feeding shaft 16, a cloth feeding tooth rack 17, a cloth feeding tooth seat 18, a movable shaft 171, a tooth lifting driving source 21, a tooth lifting tooth shaft 22, a tooth lifting tooth fork-shaped crank 23, a shaft connector 24, a first crank 25, a first connecting rod 26, a second crank 27, a cloth feeding tooth 31, a trimming and presser foot lifting motor 41, a trimming crank 51, a pushing piece 511, a trimming fork wheel 52, a trimming rod 521, a return rod 522, a trimming execution end 53, a presser foot lifting cam 61, a presser foot lifting cam lifting surface 611, an idle circular arc surface 612, a lifter rod 62, a presser foot lifting execution end 63, a presser foot 71, a base plate 72 and a machine body 73.

Detailed Description

Preferred embodiments of the present application will be described in detail below with reference to fig. 1 to 7, so that the advantages and features of the present application can be more easily understood by those skilled in the art, and the scope of protection of the present application will be clearly and clearly defined, and these embodiments are only for illustrating the present invention and are not limited thereto.

Example one

The application provides a sewing machine has feed dog actuating mechanism, trimming and lifts presser foot actuating mechanism and control system. The feed dog driving mechanism includes a feed motor 11, a feed dog driving source 21, a feed dog 31, and transmission components for indirectly driving the feed dog 31 by the feed motor 11 and the feed dog driving source 21, and is a front and rear feed motion unit. The feed motor 11 and the feed lifting drive source 21 start driving at the same time and indirectly act on the feed dog 31, so that the feed dog 31 generates feed motion, and the driving is finished at the same time. The cloth feeding motor 11 is arranged and fixed on the machine body 73 at the side edge of the sewing machine, and the output shaft 12 of the cloth feeding motor connected with the cloth feeding motor 11 penetrates through the machine body 73; the feed dog driving source 21 is mounted and fixed below the base plate 72 of the sewing machine, and a motor is preferably used as the feed dog driving source 21.

The cloth feeding motor output shaft 12 connected with the cloth feeding motor 11 is fixedly provided with a swinging crank 13, the cloth feeding motor 11 operates in a repeated back-and-forth swinging mode under the control of a control system to enable the swinging crank 13 to generate repeated swinging motion, and the swinging crank 13 indirectly transmits the repeated swinging motion to the cloth feeding teeth 31, so that the cloth feeding teeth 31 have front and back cloth feeding motions.

Specifically, the oscillating crank 13 transmits the repeated oscillating motion to the feed dog 31 by the following technical scheme: the feed dog driving mechanism also comprises a swing crank 13, a connecting rod 14, a feed shaft crank 15, a feed shaft 16 and a feed dog frame 17. The swing crank 13 is hinged with a connecting rod 14, the connecting rod 14 is hinged with a cloth feeding shaft crank 15, the cloth feeding shaft crank 15 is fixed on the rear end of a cloth feeding shaft 16, the front end of the cloth feeding shaft 16 is connected with a cloth feeding tooth holder 18, the cloth feeding tooth holder 18 is connected with a cloth feeding tooth frame 17, and a cloth feeding tooth 31 is fixed on the cloth feeding tooth frame 17. The swing crank 13 realizes the generation of the lower and upper cloth feeding actions by the cloth feeding teeth 31 driven by the cloth feeding motor 11, here, the cloth feeding motor output shaft 12 of the cloth feeding motor 11 can also be directly fixed on the cloth feeding shaft crank 15, the swing source is transmitted to the cloth feeding shaft crank 15, then is sequentially transmitted to the cloth feeding shaft 16 and the cloth feeding teeth frame 17 by the cloth feeding shaft crank 15, and finally reaches the cloth feeding teeth 31, the technical effect is the same as the swing crank 13, and the cloth feeding teeth 31 can generate the lower and upper cloth feeding actions.

The feed dog driving mechanism has a feed dog driving source 21, a feed dog shaft 22, a feed dog fork crank 23, a feed dog holder 17, and a feed dog 31, which are upper and lower feed assemblies. The feed dog driving source 21 is connected with a feed dog shaft 22, the other end of the feed dog shaft 22 is connected with a feed dog fork-shaped crank 23, and the feed dog fork-shaped crank 23 is matched with a movable shaft 171 of the feed dog frame 17. The feed dog driving source 21 is operated in a reciprocating manner under the control of the control system, so that the feed dog shaft 22 and the feed dog forked crank 23 generate a reciprocating motion, the feed dog shaft 22 transmits the reciprocating motion to the feed dog 31 through the feed dog holder 17, and the feed dog 31 has a vertical feed motion. Here, the tooth lifting drive source 21 is preferably a drive device capable of operating in a reciprocating manner, and here, a motor may be preferably used as the drive source.

The cloth feeding motor 11 enables the cloth feeding teeth 31 to generate front and back cloth feeding actions and the cloth feeding teeth 31 to generate upper and lower cloth feeding actions by combining the cloth feeding teeth driving source 21, the cloth feeding teeth 31 form a cloth feeding function when the sewing machine performs sewing, the sewing machine breaks through the technical scheme of the traditional sewing machine, a cloth feeding connecting rod, a tooth lifting connecting rod and a cam on a main shaft of the traditional sewing machine are eliminated, the tooth lifting shaft 22 (actually equivalent to the tooth lifting shaft) can be made shorter to reduce the manufacturing cost, the tooth lifting amplitude of the cloth feeding teeth 31 is controlled by a control system, the intelligent level of sewing is further improved, and the traditional part of the swing seat is removed, and the functions of the swing seat can be completely achieved. The feed motor 11 and the feed lifting tooth driving source 21 start driving and stop driving at the same time under the control of the control system to achieve the coordinated feed motion of the feed lifting tooth driving mechanism, and avoid the feed lifting tooth 31 from having no feed lifting tooth motion or having only feed lifting tooth motion without transmitting the uncoordinated sewing motion of the feed motion. Because the repeated swinging-back operation mode of the cloth feeding motor 11 and the feed lifting tooth driving source 21 is preset by the control system, the cloth feeding action of the cloth feeding tooth 31 is always in a constant stitch length to carry out sewing work, namely, the cloth feeding and the feed lifting tooth are in a constant state, the condition that the size of the stitch length is deviated before and after the existing sewing machine technology is overcome, and the sewing quality and the stability of the sewing work are effectively improved.

The angle of the feed motor 11 repeatedly swinging back and forth under the control of the control system determines the stitch length of the feed dog 31 in sewing, namely the angle of the feed dog driving source 21 repeatedly swinging back and forth determines the amplitude of the feed when the feed dog 31 is in sewing.

The sewing machine also has the function of positioning the stop position of the feed dog 31, specifically the zero-gauge position of the feed dog 31 and the stop height of the feed dog 31.

Under the control of the control system, the cloth feeding motor 11 has a function of positioning the zero-gauge position of the cloth feeding dog 31, the zero-gauge position is a theoretical needle in-situ thread running position of the sewing machine (the sewing machine cannot generate actual in-situ thread running motion), and the zero-gauge position is generated when the cloth feeding dog 31 loses front and back cloth feeding motion. The zero-gauge position of the positioned feed dog 31 corresponds to the center position of the feed motor 11 which repeatedly swings back and forth, in other words, the feed motor 11 stays at the center position of the repeated swing back and forth after the zero-gauge position of the feed dog 31 is positioned, and the repeated swing back and forth of the feed motor 11 is the repeated rotation back and forth at the center position.

Under the control of the control system, the feed dog driving source 21 has a function of positioning the stop height of the feed dog 31, and the feed dog 31 is stopped below the needle plate 71 when the sewing is finished. The feed dog driving source 21 has the function of stopping the feed dog 31 below the needle plate 71, can effectively overcome the characteristic that the stopping position of the existing sewing machine is uncertain when sewing is finished, and effectively solves the problem that the high needle plate 71 at the stopping position of the feed dog 31 causes the sewing materials to be damaged and other adverse factors in the prior art, thereby improving the sewing quality of the sewing machine.

The trimming and presser foot lifting driving mechanism of the sewing machine is provided with a trimming component and a presser foot lifting component, wherein the trimming component is provided with a trimming and presser foot lifting motor 41, a trimming crank 51, a trimming fork wheel 52 and a trimming execution end 53. Wherein the trimming crank 51 is provided with a pushing piece 511, and the pushing piece 511 is arranged at the eccentric position of the trimming crank 51. The pushing piece 511 pushes the thread cutting fork wheel 52 to perform thread cutting action, the thread cutting fork wheel 52 is provided with a return rod 522 and a thread cutting rod 521, and the pushing piece 511 is positioned between the return rod 522 and the thread cutting rod 521. Under the driving of the thread cutting crank 51 by the thread cutting and presser foot lifting motor 41, the pushing piece 511 pushes the thread cutting rod 521 to enable the thread cutting execution end 53 to execute thread cutting action.

The presser foot lifting assembly is provided with a trimming and presser foot lifting motor 41, a presser foot lifting cam 61, a presser foot lifting ejector rod 62 and a presser foot lifting execution end 63, the presser foot lifting cam 61 is provided with a presser foot lifting cam lifting surface 611 and an idle circular arc surface 612, the presser foot lifting cam 61 is fixed on an output shaft of the trimming and presser foot lifting motor 41, the presser foot lifting cam lifting surface 611 is used for adjusting the presser foot lifting ejector rod 62 to be at a lower position or a higher position to be at a higher position or a lower position, and the idle circular arc surface 612 is used for idle rotation between the presser foot lifting ejector rod 62 and the presser foot lifting cam 61. The idle circular arc surface 612 is concentric with the output shaft of the trimming and presser foot lifting motor 41, and the presser foot lifting cam lifting surface 611 is located at the cam portion of the presser foot lifting cam 61.

After the thread trimming operation is completed, the presser foot lifting cam 61 starts to perform the presser foot lifting operation, the actual presser foot lifting operation of the presser foot lifting cam 61 on the presser foot lifting ejector rod 62 is not generated by the rotation angle of the thread trimming and presser foot lifting motor 41 during the thread trimming operation, and the presser foot lifting ejector rod 62 and the idle circular arc surface 612 idle. The trimming and presser foot lifting motor 41 drives the presser foot lifting cam lifting surface 611 of the presser foot lifting cam 61 to lift the presser foot lifting ejector rod 62, the presser foot lifting ejector rod 62 is lifted to the highest point when the highest point of the presser foot lifting ejector rod 62 is reached, and the presser foot lifting execution end 63 completes the presser foot lifting action.

The thread trimming and presser foot lifting motor 41 drives the presser foot lifting cam 61 in a proper manner during thread trimming, the presser foot lifting cam 61 gradually transits the presser foot lifting ejector rod 62 from the idle circular arc surface 612 to the presser foot lifting cam lifting surface 611 under the driving of the thread trimming and presser foot lifting motor 41 until reaching the highest point of the presser foot lifting, so that the presser foot lifting action is realized, at the moment, the thread trimming and presser foot lifting motor 41 is locked, the presser foot lifting state is maintained for a period of time, and the sewing action of immediately lifting the presser foot after thread trimming is formed.

In addition, in the presser foot lifting process, the pushing piece 511 pushes the return rod 522, so that the pushing piece 511 pushes the return rod 522 to the original position, the whole thread cutting assembly is reset, the thread cutting assembly can be effectively and directly returned to the original position in the fault state of clamping, and the resetting function is achieved.

When the presser foot is to be lowered, the thread trimming and presser foot lifting motor 41 returns the presser foot lifting ejector rod 62 from the presser foot lifting cam lifting surface 611 to the idle circular arc surface 612, so that the presser foot lowering action is realized.

There is another scenario where the presser foot is lifted without cutting the thread, and usually stitches are made under a large degree of bending. The thread cutting and presser foot lifting motor 41 drives the presser foot lifting cam lifting surface 611 to jack the presser foot lifting mandril 62 to the highest point of the presser foot, and when the presser foot is placed, the thread cutting and presser foot lifting motor 41 drives the presser foot lifting cam lifting surface 611 to return reversely to complete the action of the presser foot placement.

Example two

In fig. 6, the second embodiment is substantially the same as the first embodiment, except that the above-mentioned tooth lifting drive source 21 and the tooth lifting shaft 22 are connected by the coupling 24, the coupling 24 is installed to make the connection between the tooth lifting drive source 21 and the tooth lifting shaft 22 more convenient and faster, and the tooth lifting drive source 21 is transmitted to the tooth lifting shaft 22 through the coupling 24 in a repeated swinging-back operation mode, which has the same technical effects as the first embodiment.

EXAMPLE III

In fig. 7, the third embodiment is substantially the same as the first embodiment, except that a first crank 25 is mounted on the output shaft of the feed lifting teeth driving source 21, a second crank 27 is mounted and connected on the feed lifting teeth shaft 22 at the side close to the feed lifting teeth driving source 21, and the first crank 25 and the second crank 27 are hinged by a first connecting rod 26. The feed lifting teeth driving source 21 is transmitted to the feed lifting teeth shaft 22 through the first crank 25, the first connecting rod 26 and the second crank 27 in a repeated swinging back and forth operation mode, and the technical effect is the same as that of the embodiment.

The above description is only one of the preferred embodiments of the present application, and not intended to limit the scope of the present application, and all modifications that can be made to the equivalent structure or equivalent flow path by using the shape, structure and principle of the present application and the accompanying drawings, or applied to other related fields directly or indirectly are included in the scope of the present application.

Claims (9)

1. A sewing machine is provided with a cloth feeding shaft and a feed lifting tooth shaft, wherein the cloth feeding shaft and the feed lifting tooth shaft are indirectly connected with a feed lifting tooth; the feed lifting tooth driving source is connected with a feed lifting tooth shaft, the other end of the feed lifting tooth shaft is connected with a feed lifting tooth fork-shaped crank, and the feed lifting tooth fork-shaped crank is matched with a movable shaft of the feed feeding tooth frame.

2. The sewing machine of claim 1, wherein the feed motor output shaft of the feed motor is fixed to the feed shaft crank.

3. The sewing machine of claim 1, wherein the feed dog driving source is mounted and fixed to a base plate of the sewing machine, and the feed dog driving source uses a motor.

4. The sewing machine of claim 1, wherein the feed dog driving source and the feed dog shaft are coupled by a coupling.

5. The sewing machine of claim 1, wherein the output shaft of the feed lifting teeth driving source is provided with a first crank, the feed lifting teeth shaft is provided with a second crank on one side close to the feed lifting teeth driving source, and the first crank and the second crank are hinged through a first connecting rod.

6. The sewing machine of claim 1, wherein the feed motor is mounted on and secured to the machine body at a side of the sewing machine, and an output shaft of the feed motor connected to the feed motor passes through the machine body.

7. The sewing machine of claim 1, wherein the feed motor is operated in a reciprocating manner under control of the control system to cause the rocking crank to produce a reciprocating motion, the rocking crank indirectly transmitting the reciprocating motion to the feed dog, such that the feed dog has a back and forth feed motion.

8. The sewing machine of claim 1, wherein the feed dog driving source operates in a reciprocating manner under the control of the control system to generate a reciprocating motion of the feed dog shaft and the feed dog forked crank, and the feed dog shaft transmits the reciprocating motion to the feed dog through the feed dog holder so that the feed dog has an up-and-down feed motion.

9. The sewing machine of claim 1, further comprising a presser foot lifting assembly and a thread trimming assembly, wherein the presser foot lifting assembly comprises a thread trimming and presser foot lifting motor, a presser foot lifting cam, a presser foot lifting mandril and a presser foot lifting execution end, the presser foot lifting cam comprises a presser foot lifting cam lifting surface and an idle rotation arc surface, the presser foot lifting cam is fixed on an output shaft of the thread trimming and presser foot lifting motor, the presser foot lifting cam lifting surface is used for adjusting the lower position or the higher position of the presser foot lifting mandril to the higher position or the lower position, the idle rotation arc surface is used for idle rotation between the presser foot lifting mandril and the presser foot lifting cam, the idle rotation arc surface and the output shaft of the thread trimming and presser foot lifting motor are arranged concentrically, and the presser foot lifting cam lifting surface is positioned at a presser foot lifting part of the presser foot lifting cam;

the thread trimming component is provided with a thread trimming and presser foot lifting motor, a thread trimming crank, a thread trimming fork wheel and a thread trimming execution end, the thread trimming crank is provided with a pushing piece, the pushing piece is arranged at the eccentric position of the thread trimming crank and pushes the thread trimming fork wheel to perform thread trimming action, the thread trimming fork wheel is provided with a return rod and a thread trimming rod, the pushing piece is positioned between the return rod and the thread trimming rod, and the pushing piece pushes the thread trimming rod to enable the thread trimming execution end to execute the thread trimming action under the condition that the thread trimming and presser foot lifting motor drives the thread trimming crank;

after the thread trimming action is finished, the presser foot lifting cam starts to perform the presser foot lifting action, the rotation angle of the thread trimming and presser foot lifting motor does not enable the presser foot lifting cam to generate actual presser foot lifting action on the presser foot lifting ejector rod during the thread trimming action, the presser foot lifting ejector rod and the idle circular arc surface are in idle rotation, the thread trimming and presser foot lifting motor drives the presser foot lifting cam lifting surface of the presser foot lifting cam to lift the presser foot lifting ejector rod, the presser foot lifting ejector rod is lifted to the highest point when the highest point of the presser foot lifting ejector rod is reached, and the presser foot lifting execution end completes the presser foot lifting action;

in the presser foot lifting process, the pushing piece pushes the return rod, so that the pushing piece pushes the return rod to the original position, the whole thread cutting assembly is reset, the thread cutting assembly can be effectively and directly returned to the original position in the fault state of clamping, and the resetting function is realized;

when the presser foot is to be lowered, the trimming and presser foot lifting motor returns the presser foot lifting ejector rod to the idle running arc surface from the presser foot lifting cam lifting surface under the action of the clockwise force, so that the action of lowering the presser foot is realized.

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