CN215328714U - Rotating shuttle thread hooking and cutting integrated driving sewing machine - Google Patents

Abstract

The utility model relates to a sewing machine with rotating shuttle hook and cut integrally driven, which comprises a rotating shuttle hook mechanism, a cut mechanism, a motor and an electromagnetic clutch mechanism, the motor is provided with a front shaft and a rear shaft, the electromagnetic clutch mechanism comprises an electromagnet assembly and an elastic limit structure, the electromagnet assembly comprises a body with an electromagnetic coil and an iron core positioned in the body, the body is fixed on the motor, the iron core is arranged on the front shaft, the iron core and the front shaft are fixed in the circumferential direction and can slide relatively in the axial direction, the iron core is provided with a connecting structure which is used for being matched and connected with the thread trimming mechanism, the elastic limiting structure is used for separating the iron core from the thread trimming mechanism, the iron core slides to the connecting structure to be connected and matched with the thread trimming mechanism when the body is electrified, and the iron core drives the thread trimming mechanism to move through the connecting structure; and the rear shaft of the motor is connected with the rotating shuttle thread hooking mechanism and is used for driving the rotating shuttle thread hooking mechanism to move.

Description

Rotating shuttle thread hooking and cutting integrated driving sewing machine

Technical Field

The utility model relates to the field of sewing machinery, in particular to a sewing machine with a rotating shuttle capable of integrally driving thread hooking and cutting.

Background

At present, the middle and high-end flush joint machines in the market adopt a stepping or servo motor independent driving module to carry out independent automatic thread cutting or rotating shuttle thread hooking actions, so that the function of automatically adjusting various sewing parameters is realized to improve the sewing performance of the whole machine. By adopting the design, the action of hooking and cutting threads is carried out by adopting the independent driving module, so that the driving module in the sewing machine is too many, the installation is complex, the production cost is increased, and the competition of products is not facilitated.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned drawbacks of the prior art, the present invention provides a sewing machine with integrated driving of hook and cut of a rotating shuttle, which can simultaneously drive the hook and cut of a thread by a motor, simplify the mechanism, increase the functions, meet the sewing requirements of customers, and reduce the production cost.

In order to achieve the aim, the utility model provides a sewing machine with integrated driving of hook and cut of a rotating shuttle, which comprises a hook mechanism of the rotating shuttle, a cut mechanism of the rotating shuttle, a motor and an electromagnetic clutch mechanism, the motor is provided with a front shaft and a rear shaft, the electromagnetic clutch mechanism comprises an electromagnet assembly and an elastic limit structure, the electromagnet assembly comprises a body with an electromagnetic coil and an iron core positioned in the body, the body is fixed on the motor, the iron core is arranged on the front shaft, the iron core and the front shaft are fixed in the circumferential direction and can slide relatively in the axial direction, the iron core is provided with a connecting structure which is used for being matched and connected with the thread trimming mechanism, the elastic limiting structure is used for separating the iron core from the thread trimming mechanism, the iron core slides to the connecting structure to be connected and matched with the thread trimming mechanism when the body is electrified, and the iron core drives the thread trimming mechanism to move through the connecting structure; and the rear shaft of the motor is connected with the rotating shuttle thread hooking mechanism and is used for driving the rotating shuttle thread hooking mechanism to move.

Furthermore, the front shaft of the motor is provided with a connecting section with a non-circular cross section, a connecting hole matched with the shape of the connecting section is formed in the iron core, and the iron core is sleeved on the connecting section of the front shaft through the connecting hole.

Further, the elastic limiting structure is integrated with the electromagnet assembly.

Furthermore, the rotating shuttle thread hooking mechanism comprises a lower middle shaft, a rotating shuttle assembly arranged on the lower middle shaft and a transmission structure arranged between the lower middle shaft and the rear shaft of the motor, wherein the transmission structure comprises a first belt wheel fixed on the rear shaft of the motor, a second belt wheel fixed on the lower middle shaft and a synchronous belt connecting the first belt wheel and the second belt wheel.

Further, the connection structure on the iron core comprises an insertion block, a clamping groove is formed in the wire cutting mechanism and is connected with the iron core through a matched connecting piece, and the insertion block can be inserted into the clamping groove.

Furthermore, the trimming mechanism comprises a fixed cutter and a movable cutter which are arranged oppositely, a trimming cam used for being connected and matched with the iron core, and a trimming middle structure for connecting the trimming cam and the movable cutter, wherein the trimming cam is sleeved on a front shaft of the motor, and is limited in the axial direction of the front shaft and freely and relatively rotates with the front shaft in the circumferential direction; when the trimming cam rotates, the trimming intermediate structure drives the movable knife to move to trim the wires.

Further, the trimming intermediate structure comprises a trimming drive shaft, a trimming rear crank, a trimming crank shaft, a trimming front crank, a trimming connecting rod and a movable cutter crank, the trimming drive shaft rear end is connected with the trimming cam and driven by the trimming cam to rotate, one end of the trimming rear crank is fixedly connected with the trimming drive shaft front end, the trimming crank shaft rear end is connected with the trimming rear crank other end and driven by the trimming rear crank to rotate, the trimming crank shaft front end is fixedly connected with one end of the trimming front crank, the trimming front crank other end is hinged with the trimming connecting rod, the movable cutter crank is hinged with the trimming connecting rod, and the fixed cutter is installed on the movable cutter crank.

Further, elasticity limit structure includes spacing spring, spacing spring sets up between trimming cam and iron core.

Further, the sewing machine further comprises a bracket fixed on a bottom plate of the sewing machine, and the motor is installed on the bracket.

As described above, the sewing machine according to the present invention has the following advantageous effects:

through setting up motor and electromagnetic clutch mechanism, the during operation, the motor rotates, colludes the line action through the motion of rear axle drive rotating shuttle mechanism of colluding, and the front axle can drive electromagnet assembly's iron core and rotate, and the body does not switch on this moment, and elasticity limit structure restricts the iron core in the body, and the mechanism separation of trimming consequently can not drive the mechanism action of trimming. When the wire shearing action is needed, the body is electrified, acting force is provided for the iron core through the electromagnetic effect, the iron core overcomes the limitation of the elastic limiting structure and slides on the rear shaft, the connecting structure on the iron core is connected and matched with the wire shearing mechanism, the wire shearing mechanism is driven to move through the connecting structure when the iron core rotates, power is transmitted to the wire shearing mechanism, and therefore the wire shearing action is achieved. The sewing machine can simultaneously realize the thread hooking action and the thread cutting action through the motor, simplifies the mechanism compared with the prior mode that the rotating shuttle thread hooking mechanism and the thread cutting mechanism are respectively and independently driven to act through two driving sources, not only can meet the sewing requirements of customers, but also can reduce the production cost.

Drawings

FIG. 1 is a schematic view showing the mounting of a motor on a bed plate in the sewing machine of the present invention.

Fig. 2 is a schematic structural diagram of a motor, an electromagnetic clutch mechanism and a rotating shuttle thread hooking mechanism in the utility model.

Fig. 3 is a schematic structural diagram of the motor, the electromagnetic clutch mechanism and the trimming cam in the utility model.

Fig. 4 is a schematic diagram of the electromagnetic clutch mechanism and the trimming cam in the utility model.

Fig. 5 is a schematic structural view of the iron core of the present invention.

Description of the element reference numerals

1 base plate

2 electric machine

3 support

4 electromagnet assembly

41 body

42 iron core

42a connecting hole

42b insert block

5 trimming cam

5a inner cam groove

5b card slot

6 limiting retainer ring

7 shear line connecting rod

8 move sword crank

9 fixed knife

10 rotating shuttle assembly

11 moving knife

12 trimming front crank

13 reset torsion spring

14 front axle sleeve of trimming

15 thread cutting crank shaft

15a connecting plate part

16 square sliding block

17 rear crank for trimming

18 rear axle sleeve of trimming

19 line cutting driving shaft

20 roller

21 limiting spring

22 synchronous belt

23 first pulley

24 rear middle shaft sleeve

25 second belt wheel

26 lower middle axle

27 lower retainer ring

28 front middle axle sleeve

29 front axle sleeve

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

It should be understood that the structures, proportions, and dimensions shown in the drawings and described herein are for illustrative purposes only and are not intended to limit the scope of the present invention, which is defined by the claims, but rather by the claims. In addition, the terms such as "upper", "lower", "left", "right" and "middle" used in the present specification are for convenience of description only, and are not intended to limit the scope of the present invention, and changes or modifications of the relative relationship thereof may be regarded as the scope of the present invention without substantial changes in the technical contents.

Referring to fig. 1 to 5, the utility model provides a sewing machine with integrated driving of hook and cut of rotating shuttle, comprising a hook mechanism and a cut mechanism of rotating shuttle, further comprising a motor 2 and an electromagnetic clutch mechanism, wherein the motor 2 is provided with two output shafts of a front shaft and a rear shaft, the electromagnetic clutch mechanism comprises an electromagnet assembly 4 and an elastic limit structure, the electromagnet assembly 4 comprises a body 41 provided with an electromagnetic coil and an iron core 42 positioned in the body 41, the body 41 is fixed on the motor 2, the iron core 42 is arranged on the front shaft, the iron core 42 and the front shaft are circumferentially fixed and can axially slide relatively, the iron core 42 is provided with a connecting structure which is matched and connected with the thread trimming mechanism, the elastic limiting structure is used for separating the iron core 42 from the thread trimming mechanism, the iron core 42 slides to the connecting structure to be connected and matched with the thread trimming mechanism when the body 41 is electrified, and the iron core 42 drives the thread trimming mechanism to move through the connecting structure; the rear shaft of the motor 2 is connected with the rotating shuttle thread hooking mechanism and used for driving the rotating shuttle thread hooking mechanism to move.

When the sewing machine works, the motor 2 rotates, the rotating shuttle thread hooking mechanism is driven to move through the rear shaft to hook threads, the front shaft can drive the iron core 42 of the electromagnet assembly 4 to rotate, the body 41 is not electrified at the moment, the iron core 42 is limited in the body 41 by the elastic limiting structure and is separated from the thread cutting mechanism, and therefore the thread cutting mechanism cannot be driven to move. When the thread trimming action is required, the body 41 of the electromagnet assembly 4 is controlled to be electrified, acting force is provided for the iron core 42 through the electromagnetic effect, the iron core 42 overcomes the limitation of the elastic limiting structure and slides on the rear shaft, the connecting structure on the iron core 42 is connected and matched with the thread trimming mechanism, the iron core 42 drives the thread trimming mechanism to move through the connecting structure when rotating, power is transmitted to the thread trimming mechanism, and therefore the thread trimming action is achieved. The sewing machine can simultaneously realize the thread hooking action and the thread cutting action through the motor 2, simplifies the mechanism compared with the prior mode that the rotating shuttle thread hooking mechanism and the thread cutting mechanism are respectively and independently driven to act through two driving sources, not only can meet the sewing requirements of customers, but also can reduce the production cost. Wherein the body 41 of the electromagnet assembly 4, when energized, will move the iron core 42 therein under the electromagnetic effect, which part is known in the art and therefore will not be described in detail.

Referring to fig. 1 to 5, the present invention is further illustrated in a specific embodiment as follows:

in this embodiment, referring to fig. 1, as a preferred design, the motor 2 may specifically adopt a servo motor, a front shaft of the motor 2 has a connecting section with a non-circular cross section, a connecting hole 42a adapted to the shape of the connecting section is provided in the iron core 42, and the iron core 42 is sleeved on the connecting section of the rear shaft through the connecting hole 42a, so that the iron core 42 can freely slide in the axial direction of the front shaft, and the two are fixed in the circumferential direction, thereby achieving synchronous rotation. The cross section of the connecting section can be in various shapes, specifically, a plane can be processed on the circular rear shaft to form a major arc arch or a D shape of the cross section of the connecting section, and referring to fig. 5, correspondingly, the shape of the connecting hole 42a is the major arc arch or the D shape, so that the installation is convenient.

In the present embodiment, referring to fig. 2, the rotating shuttle hook mechanism includes a lower middle shaft 26, a rotating shuttle assembly 10 mounted on the lower middle shaft 26, and a transmission structure disposed between the lower middle shaft 26 and a rear shaft of the motor 2, specifically, different positions of the lower middle shaft 26 are respectively mounted in a rear middle shaft sleeve 24, a front middle shaft sleeve 28, and a front shaft sleeve 29, the rear middle shaft sleeve 24, the front middle shaft sleeve 28, and the front shaft sleeve 29 are mounted under the bottom plate 1, and the lower middle shaft 26 completes an axial limiting function by mounting a lower retainer 27, thereby realizing a stable mounting of the lower middle shaft 26. In this embodiment, the transmission structure includes a first belt pulley 23 fixed on the rear shaft of the motor 2, a second belt pulley 25 fixed on the lower middle shaft 26, and a synchronous belt 22 connecting the first belt pulley 23 and the second belt pulley 25, and when the rear shaft of the motor 2 rotates, the lower middle shaft 26 is driven to rotate by the first belt pulley 23, the synchronous belt 22, and the second belt pulley 25, so as to drive the rotating shuttle assembly 10 to hook the thread. The transmission ratio of the transmission structure is determined according to the rotating speeds of the motor 2 and an upper shaft spindle motor of the sewing machine, for example, the motor 2 and the upper shaft spindle motor move in a synchronous rotating speed of 1:1, and a 1:2 speed ratio is required to be formed for transmission with the rotating shuttle, so that the transmission ratio of the first belt wheel 23 and the second belt wheel 25 is 1: 2. Certainly, the rotating shuttle thread hooking mechanism is not limited to the above form, and in other embodiments, other existing suitable mechanisms may be adopted, wherein the transmission structure may also adopt other transmission structures such as gear transmission, and in addition, the motor 2 may also adopt a customized high-speed servo motor 2 and directly connect with the lower middle shaft 26 to directly control the thread hooking action, and cancel the middle transmission structure.

In this embodiment, referring to fig. 2, 3 and 4, as a preferred design, the connection structure on the iron core 42 includes an insertion block 42b, the connection member in the trimming mechanism that is connected and matched with the iron core 42 is a trimming cam 5, a clamping groove 5b is provided on the rear end surface of the trimming cam 5, the insertion block 42b can be inserted into the clamping groove 5b, so as to realize connection and matching with the trimming cam 5, and the insertion block 42b and the clamping groove 5b transmit torque force to drive the trimming cam 5 to rotate. When the insert 42b is disengaged from the slot 5b, the iron core 42 is separated from the trimming cam 5, and the trimming cam 5 is no longer driven to rotate.

In this embodiment, referring to fig. 2, 3 and 4, the thread trimming mechanism includes a fixed cutter 9 and a movable cutter 11 which are arranged oppositely, a thread trimming cam 5 for connecting and matching with the iron core 42, and a thread trimming intermediate structure connecting the thread trimming cam 5 and the movable cutter 11, the thread trimming cam 5 is sleeved on the front shaft of the motor 2, and the thread trimming cam 5 is limited by a limit retainer ring 6 fixed on the front shaft in the front axial direction, so that the thread trimming cam 5 does not move axially, the thread trimming cam 5 and the front shaft are not constrained in the circumferential direction, and can rotate freely and relatively without being driven by the rear shaft, and the movable cutter 11 is driven by the transmission action of the thread trimming intermediate structure to perform a thread trimming action when the thread trimming cam 5 rotates.

In the present embodiment, referring to fig. 2, 3 and 4, the trimming intermediate structure includes a trimming drive shaft 19, a trimming rear crank 17, a trimming crank shaft 15, a reset torsion spring 13, a trimming front crank 12, a trimming connecting rod 7 and a movable knife crank 8, the trimming drive shaft 19 is connected to the trimming cam 5 and is driven to rotate by the trimming cam 5, specifically, an inner cam groove 5a is formed in the trimming cam 5, the trimming drive shaft 19 is rotatably mounted under the base plate 1 through a trimming rear shaft sleeve 18, a crank portion is formed at the rear end of the trimming drive shaft 19, a roller 20 is mounted on the crank portion, the roller 20 is mounted in the inner cam groove 5a and can flexibly roll, and the trimming drive shaft 19 is driven to rotate by the cooperation of the roller 20 and the inner cam groove 5a when the trimming cam 5 rotates. One end of the thread trimming rear crank 17 is fixedly connected with the front end of the thread trimming driving shaft 19. The trimming crank shaft 15 is rotatably installed below the bottom plate 1 through a trimming front shaft sleeve 14, the rear end of the trimming crank shaft 15 is connected with the other end of the trimming rear crank 17 and is driven to rotate by the trimming rear crank 17, specifically, a rotatable slide block 16 is arranged at the end part of the trimming rear crank 17, a connecting plate part 15a is arranged at the rear end of the trimming crank shaft 15, a straight slide groove matched with the slide block 16 is formed in the connecting plate part 15a, the slide block 16 is installed in the straight slide groove and can freely slide, the slide block 16 and the trimming crank shaft 15 form a sliding pair installation, and the trimming crank shaft 15 is driven to rotate through the matching of the slide block 16 and the straight slide groove when the trimming rear crank 17 rotates. One end of a trimming front crank 12 is fixedly connected with the front end of a trimming crank shaft 15, the other end of the trimming front crank is hinged with one end of a trimming connecting rod 7, a movable cutter crank 8 is hinged with the other end of the trimming connecting rod 7, and a fixed cutter 9 is installed on the movable cutter crank 8. The reset torsion spring 13 is sleeved on the trimming front shaft sleeve 14, and the reset torsion spring 13 acts on the trimming front crank 12. When a thread is required to be cut, after the iron core 42 is connected with the thread cutting cam 5 in a matched mode, the iron core 42 can drive the thread cutting cam 5 to rotate when rotating along with the front shaft of the motor 2, the thread cutting cam 5 drives the thread cutting driving shaft 19 to rotate through the inner cam groove 5a and the roller 20, the thread cutting driving shaft 19 drives the thread cutting rear crank 17 to swing, the thread cutting rear crank 17 drives the thread cutting crank shaft 15 to rotate through the motion matching of the straight sliding groove and the sliding block 16, the thread cutting crank shaft 15 drives the thread cutting front crank 12 to swing, the reset torsion spring 13 is twisted at an elastic energy storage state at the moment, and the thread cutting front crank 12 drives the movable knife crank 8 to move through the thread cutting connecting rod 7 when swinging, so that the movable knife 11 is driven to move, the movable knife 11 is meshed with the fixed knife 9, and thread cutting operation is achieved. After the trimming is finished, the reset torsion spring 13 can assist the trimming front crank 12 to rotate and reset, so that the movable knife 11 is assisted to reset and is separated from the fixed knife 9. In the present embodiment, an example of the hook mechanism of the rotating shuttle is given, but the hook mechanism of the rotating shuttle is not limited to the above form, and in other embodiments, other existing suitable mechanisms may be adopted, and the structure capable of driving to perform the thread trimming operation may meet the requirement.

In this embodiment, referring to fig. 3, as a preferred design, the limiting structure includes a limiting spring 21, the limiting spring 21 is sleeved on the front shaft of the motor 2 and is disposed between the trimming cam 5 and the iron core 42, the limiting spring 21 is in a compressed state, when the body 41 of the electromagnet assembly 4 is not powered on, the iron core 42 is pressed in the body 41 by the elastic force of the limiting spring 21, so that the iron core 42 is disconnected from the trimming cam 5, when the body 41 is powered on, a forward acting force is provided to the iron core 42 by an electromagnetic principle, so that the iron core 42 slides forward on the front shaft against the elastic force of the limiting spring 21 until the insertion block 42b thereon is inserted into the slot 5b of the trimming cam 5 to form a matching connection, and after the power is off, the limiting spring 21 can automatically reset the iron core 42 to be disconnected from the trimming cam 5. Preferably, the elastic limiting structure can also be integrated on the electromagnet assembly 4 to form an integrated clutch structure. In addition, the electromagnetic clutch mechanism can be integrally installed on the motor 2 as a single part, and can also be integrally designed with the motor 2 to reduce the cost.

In the present embodiment, referring to fig. 1, two brackets 3 are provided on a bed plate 11 of the sewing machine, and a front end and a rear end of a motor 2 are respectively provided on the two brackets 3, thereby realizing stable installation.

The sewing machine of the utility model has the following advantages: 1. the motor 2 integrally drives the rotating shuttle to perform the thread hooking movement and the thread cutting movement, so that the use of a driving source is reduced, the structure is simplified, the cost is lower, 2, the thread cutting action can be performed by switching on and off the electromagnetic clutch mechanism, and the use is convenient and flexible; 3. the independent motor 2 is used for driving the rotating shuttle to hook the threads, and compared with the existing design scheme that the spindle of the sewing machine is used for driving the rotating shuttle to hook the threads, the rotating shuttle hook time can be relatively adjusted, the sewing adaptability is enhanced, and the function is stronger; 4. due to the modular design, the installation and the disassembly are more convenient.

In conclusion, the present invention effectively overcomes various disadvantages of the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the utility model. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (9)

1. The utility model provides a rotating shuttle colludes line and trimming integral type driven sewing machine, includes rotating shuttle colludes line mechanism and trimming mechanism, its characterized in that: also comprises a motor (2) and an electromagnetic clutch mechanism, wherein the motor (2) is provided with two output shafts of a front shaft and a rear shaft, the electromagnetic clutch mechanism comprises an electromagnet assembly (4) and an elastic limiting structure, the electromagnet assembly (4) comprises a body (41) with an electromagnetic coil and an iron core (42) positioned in the body (41), the body (41) is fixed on the motor (2), the iron core (42) is arranged on the front shaft, the iron core (42) and the front shaft are fixed in the circumferential direction and can slide relatively in the axial direction, the iron core (42) is provided with a connecting structure which is used for being matched and connected with the thread trimming mechanism, the elastic limiting structure is used for separating the iron core (42) from the thread trimming mechanism, the iron core (42) slides to the connecting structure to be connected and matched with the thread trimming mechanism when the body (41) is electrified, and the iron core (42) drives the thread trimming mechanism to move through the connecting structure; and the rear shaft of the motor (2) is connected with the rotating shuttle thread hooking mechanism and is used for driving the rotating shuttle thread hooking mechanism to move.

2. The sewing machine of claim 1, wherein: the front shaft of the motor (2) is provided with a connecting section with a non-circular section, a connecting hole (42a) matched with the shape of the connecting section is formed in the iron core (42), and the iron core (42) is sleeved on the connecting section of the front shaft through the connecting hole (42 a).

3. The sewing machine of claim 1, wherein: the elastic limiting structure is integrated with the electromagnet assembly (4).

4. The sewing machine of claim 1, wherein: the rotating shuttle thread hooking mechanism comprises a lower middle shaft (26), a rotating shuttle assembly (10) installed on the lower middle shaft (26), and a transmission structure arranged between the lower middle shaft (26) and a rear shaft of the motor (2), wherein the transmission structure comprises a first belt wheel (23) fixed on the rear shaft of the motor (2), a second belt wheel (25) fixed on the lower middle shaft (26), and a synchronous belt (22) connected with the first belt wheel (23) and the second belt wheel (25).

5. The sewing machine of claim 1, wherein: the connection structure on iron core (42) includes inserted block (42b), set up draw-in groove (5b) on being connected the complex connecting piece with iron core (42) in the trimming mechanism, inserted block (42b) can insert in draw-in groove (5 b).

6. The sewing machine of claim 5, wherein: the trimming mechanism comprises a fixed cutter (9), a movable cutter (11), a trimming cam (5) and a trimming intermediate structure, wherein the fixed cutter and the movable cutter are oppositely arranged, the trimming cam (5) is used for being connected and matched with the iron core (42), the trimming intermediate structure is used for connecting the trimming cam (5) and the movable cutter (11), the trimming cam (5) is sleeved on a front shaft of the motor (2), and the trimming cam (5) is limited in the axial direction of the front shaft and freely and relatively rotates with the front shaft in the circumferential direction; when the trimming cam (5) rotates, the movable knife (11) is driven to act through the trimming intermediate structure to trim the wires.

7. The sewing machine of claim 6, wherein: the trimming intermediate structure comprises a trimming driving shaft (19), a trimming rear crank (17), a trimming crank shaft (15), a trimming front crank (12), a trimming connecting rod (7) and a movable cutter crank (8), the rear end of the trimming drive shaft (19) is connected with the trimming cam (5) and is driven by the trimming cam (5) to rotate, one end of the trimming rear crank (17) is fixedly connected with the front end of the trimming driving shaft (19), the rear end of the trimming crankshaft (15) is connected with the other end of the trimming rear crank (17) and is driven to rotate by the trimming rear crank (17), the front end of the trimming crank shaft (15) is fixedly connected with one end of the trimming front crank (12), the other end of the trimming front crank (12) is hinged with the trimming connecting rod (7), the movable cutter crank (8) is hinged with the trimming connecting rod (7), and the fixed cutter (9) is installed on the movable cutter crank (8).

8. The sewing machine of claim 6, wherein: the elastic limiting structure comprises a limiting spring (21), and the limiting spring (21) is arranged between the trimming cam (5) and the iron core (42).

9. The sewing machine of claim 1, wherein: the sewing machine is characterized by further comprising a support (3) fixed on the bottom plate (1) of the sewing machine, and the motor (2) is installed on the support (3).

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