阅读说明：本技术 绷缝机中剪线和抬压脚的驱动机构 (Thread trimming and presser foot lifting driving mechanism in flat seaming machine ) 是由 林群 李质彬 刘冰 陶国挺 郭灵爱 许宁鹏 连泮忠 韦思园 郑嘉滨 于 2021-10-21 设计创作，主要内容包括：本发明提供了绷缝机中剪线和抬压脚的驱动机构,属于缝纫机技术领域。它解决了结构复杂、故障率高的问题。它包括固定于机壳上的电机、固定在电机的转轴上的驱动件以及固定在压脚轴上的摆杆,电机沿竖直方向布置且电机转轴具有上端和下端,驱动件包括固定在电机的转轴上端的凸轮一以及固定在电机的转轴下端的凸轮二,凸轮一的顶部具有与摆杆相抵靠并在凸轮一转动时能推动摆杆上摆的凸轮面一,本驱动机构还包括与剪线轴固定连接的连杆组件,凸轮二转动时能推动连杆组件平移。它具有结构简洁、故障率低、生产成本低等优点。(The invention provides a driving mechanism for trimming and lifting a presser foot in a flat seaming machine, belonging to the technical field of sewing machines. The problems of complex structure and high failure rate are solved. The driving mechanism comprises a motor fixed on a machine shell, a driving piece fixed on a rotating shaft of the motor and a swing rod fixed on a presser foot shaft, wherein the motor is arranged along the vertical direction, the rotating shaft of the motor is provided with an upper end and a lower end, the driving piece comprises a first cam fixed at the upper end of the rotating shaft of the motor and a second cam fixed at the lower end of the rotating shaft of the motor, the top of the first cam is provided with a first cam surface which is abutted against the swing rod and can push the swing rod to swing upwards when the first cam rotates, the driving mechanism further comprises a connecting rod assembly fixedly connected with a shear line shaft, and the second cam can push the connecting rod assembly to move horizontally when the second cam rotates. The device has the advantages of simple structure, low failure rate, low production cost and the like.)

1. A driving mechanism for trimming and lifting presser feet in a flat seaming machine comprises a motor (10) fixed on a machine shell (1), a driving piece fixed on a rotating shaft of the motor (10) and a swing rod (13) fixed on a presser foot shaft (3), the driving mechanism is characterized in that the motor (10) is arranged in the vertical direction, a rotating shaft of the motor (10) is provided with an upper end and a lower end, the driving piece comprises a first cam (12) fixed to the upper end of the rotating shaft of the motor (10) and a second cam (15) fixed to the lower end of the rotating shaft of the motor (10), a first cam surface (12a) which abuts against the swing rod (13) and can push the swing rod (13) to swing upwards when the first cam (12) rotates is arranged at the top of the first cam (12), the driving mechanism further comprises a connecting rod assembly (16) fixedly connected with the thread shearing shaft (7), and the second cam (15) can push the connecting rod assembly (16) to move horizontally when rotating.

2. The driving mechanism for trimming and raising presser foot of flat seaming machine according to claim 1, wherein the contact point of the swing link (13) and the first cam (12) is close to the edge of the first cam surface (12 a).

3. The driving mechanism for trimming and raising presser foot of flat seaming machine according to claim 2, wherein the top of the first cam (12) has a limit protrusion (12c) protruding upward from the first cam surface (12a) along the edge thereof, and the first cam surface (12a) is located inside the limit protrusion (12c) and connected with the inner sidewall of the limit protrusion (12 c).

4. The driving mechanism for trimming and raising presser foot of flat seaming machine according to claim 3, wherein the contact part of the swing link (13) and the cam I (12) is a spherical surface.

5. The driving mechanism for trimming and presser foot lifting in a flat seaming machine according to claim 3, wherein the top of the first cam (12) is further provided with a first idle stroke surface (12b) with one end connected with the lowest position of the first cam surface (12a) and the same height, the first idle stroke surface (12b) is positioned at the inner side of the limit protrusion (12c) and connected with the inner side wall of the limit protrusion (12c), and the swing rod (13) abuts against the first idle stroke surface (12b) when the second cam (15) drives the trimming shaft (7) to translate.

6. The flat seaming machine thread trimming and presser foot lifting drive mechanism according to claim 1 or 2 or 3 or 4 or 5, the flat seaming machine is characterized in that the connecting rod assembly (16) comprises a first connecting rod (16a), a second connecting rod (16b) and a third connecting rod (16c), wherein the first connecting rod (16a) and the second connecting rod (16b) are arranged in parallel, the third connecting rod (16c) is perpendicular to the first connecting rod (16a) and is arranged in parallel with the shear spool (7), the edge of the second cam (15) is provided with a second cam surface (15a), one end of the first connecting rod (16a) is located on one side of the second cam (15) and is abutted against the edge of the second cam (15), one end of the second connecting rod (16b) is fixed with the shear spool (7), two ends of the third connecting rod (16c) are respectively fixed with the other end of the first connecting rod (16a) and the other end of the second connecting rod (16b), a guide seat (17) is fixed on the base (2) of the flat seaming machine, and the third connecting rod (16c) penetrates through the guide seat (17).

7. The driving mechanism for thread trimming and presser foot lifting in the flat seaming machine according to claim 6, characterized in that two oppositely arranged mounting seats (6) are fixed on one side of the base (2) of the flat seaming machine, the thread trimming shaft (7) passes through the two mounting seats (6), a return spring (8) and a limiting block (9) are arranged on the thread trimming shaft (7) between the two mounting seats (6), the limiting block (9) and the thread trimming shaft (7) are fixed, two ends of the return spring (8) are respectively acted on the limiting block (9) and one of the mounting seats (6), and one end of the second connecting rod (16b) is fixed on the limiting block (9).

8. The driving mechanism for trimming and raising presser foot in a flat seaming machine according to claim 6, wherein the edge of the second cam (15) is further provided with a second idle stroke surface (15b) concentrically arranged with the rotation center thereof, one end of the second idle stroke surface (15b) is connected with one end of the second cam surface (15a), and the first connecting rod (16a) is contacted with the second idle stroke surface (15b) when the first cam (12) drives the swing rod (13) to swing upwards.

9. The flat seaming machine thread trimming and presser foot lifting drive mechanism according to claim 7, the thread-releasing mechanism of the flat seaming machine is driven to release threads when the thread-releasing mechanism rotates, a control shaft (19) capable of driving the thread-releasing mechanism in the flat seaming machine to release threads is arranged on the machine shell (1), one end of the control shaft (19) extends out of one side of the machine shell (1), the driving mechanism further comprises a first connecting arm (20) with the upper end fixed on the control shaft (19), a first connecting arm (21) with the lower end fixed on the thread-cutting shaft (7) and a second connecting arm (22) with two ends respectively connected with the first connecting arm (21) and the swing arm (20), a strip-shaped movable groove (22a) is arranged at the upper end of the second connecting arm (22) in a penetrating mode, the strip-shaped movable groove (22a) is arranged in the vertical direction, and the second connecting arm (22) and the swing arm (20) penetrate through a rod part to form the strip-shaped movable groove (22a) and are fixedly connected with a fixing screw (23) in the lower end of the swing arm (20) in a threaded mode.

10. The driving mechanism for thread trimming and presser foot lifting in a flat seaming machine according to claim 1, wherein one side of the machine shell (1) is provided with a mounting groove (1a) communicated with an inner cavity of the machine shell, the mounting groove (1a) and the thread trimming shaft (7) are positioned on the same side, the motor (10) is arranged at the mounting groove (1a), the upper end and the lower end of a shell of the motor (10) are respectively connected with a mounting bracket (11), and the two mounting brackets (11) are fixed on the machine shell (1) where the notch of the mounting groove (1a) is positioned.

Technical Field

The invention belongs to the technical field of sewing machines, and relates to a driving mechanism for thread trimming and presser foot lifting in a flat seaming machine.

Background

The flat seaming machine is also called as special sewing machine, the sewing stitch is chain type sewing stitch, the stitch is used for collar rolling, edge folding, flat seaming, splicing seam, edge trimming and the like of the knitted clothes, and is sewing equipment necessary for large-scale production factories. The flat seaming machine is provided with a presser foot lifting and thread trimming mechanism, and the traditional flat seaming machine adopts two electromagnets which are independently arranged to respectively drive the thread trimming and the presser foot lifting functions, but the cost is very high.

In order to solve the problems, the prior art is improved, and a driving device for trimming and lifting a presser foot on a sewing machine with the patent application number of 201920042424.2 is provided, the sewing machine comprises a machine shell, a machine base, a presser foot rod arranged on the machine shell and a presser foot arranged at the lower end of the presser foot rod, a trimming mechanism is further arranged at the position right below the presser foot on the machine base, the driving device comprises a presser foot lifting shaft, a trimming shaft and a driving motor capable of rotating forwards and backwards, the driving motor is fixedly arranged on the machine shell, a trimming cam and a presser foot lifting cam are respectively fixedly arranged on an output shaft of the driving motor, the trimming cam and the presser foot lifting cam are respectively provided with a convex part, and the convex parts of the trimming cam and the presser foot lifting cam are arranged in a staggered manner; the thread trimming cam can drive the thread trimming shaft to move axially through the thread trimming crank, and the end part of the thread trimming shaft is connected with the thread trimming mechanism through the swing rod and can drive the thread trimming mechanism to do shearing motion; the pressure foot lifting cam can drive the pressure foot lifting shaft to rotate by lifting the pressure foot swinging rod, and the end part of the pressure foot lifting shaft is connected with the pressure foot rod through a connecting plate and can drive the pressure foot rod to move up and down. The driving motor is adopted to drive the thread trimming mechanism and the presser foot, the electromagnet is replaced, the driving source is reduced, and the production cost is reduced.

It can be known from the attached drawings of the specification that the pressure raising and pressing pin shaft is positioned at the top of the inner cavity of the machine shell, the shearing line shaft is positioned at the side part of the machine base, a larger height difference exists between the pressure raising and pressing pin shaft and the shearing line shaft, and the driving motor is specifically arranged at the position, close to the lower part, of the machine shell and is vertical to the side surface of the machine shell, so that the actual transmission structure between the pressure raising and pressing pin cam and the pressure raising and pressing pin cam is much more complicated (on one hand, the transmission parts are more, and besides the pressure raising and pressing pin swinging rod, a pressure raising and pressing pin wrench, a pressure raising and pressing pin crank, a connecting arm, a wrench shaft, a wrench crank and the like are arranged, and on the other hand, the force has multiple direction changes in the transmission process, such as the like); and the presser foot lifting cam and the thread trimming cam are both arranged on the same side of the motor, so that the problem of avoidance between each part for realizing presser foot lifting and each part for realizing thread trimming needs to be emphasized in design besides consideration of the staggered action angle between the presser foot lifting cam and the thread trimming cam. Therefore, the driving device for trimming and lifting the presser foot on the sewing machine has the problems of complex structure and high failure rate.

Disclosure of Invention

The invention aims to solve the problems in the prior art, provides a thread cutting and presser foot lifting driving mechanism in a flat seaming machine, and solves the problems of complex structure and high failure rate.

The purpose of the invention can be realized by the following technical scheme:

the driving mechanism for trimming and lifting the presser foot in the flat seaming machine comprises a motor fixed on a machine shell, a driving piece fixed on a rotating shaft of the motor and a swing rod fixed on a presser foot shaft, and is characterized in that the motor is arranged along the vertical direction, the rotating shaft of the motor is provided with an upper end and a lower end, the driving piece comprises a first cam fixed at the upper end of the rotating shaft of the motor and a second cam fixed at the lower end of the rotating shaft of the motor, the top of the first cam is provided with a first cam surface which is abutted against the swing rod and can push the swing rod to swing upwards when the first cam rotates, the driving mechanism further comprises a connecting rod assembly fixedly connected with the trimming shaft, and the second cam can push the horizontal moving when the second cam rotates.

When the presser foot needs to be lifted, the rotating shaft of the motor rotates towards one direction, the contact point between the cam I and the swing rod is changed from the lowest point of the cam I to the highest point of the cam I along with the rotation of the cam I, the swing rod can swing upwards under stress in the process, and then the presser foot shaft rotates and lifts the presser foot upwards; when the wire is required to be cut, the rotating shaft of the motor rotates towards the other direction, the cam II pushes the connecting rod assembly, and the connecting rod assembly is fixed with the wire cutting shaft, so that the wire cutting shaft can also translate to complete the wire cutting action.

The driving mechanism arranges the motor along the vertical direction, and directly drives the swing rod to swing by combining the height change of the contact position of the cam surface I arranged at the top of the cam I and the swing rod, so that the position of the cam I and the position of a thread shearing shaft are closer, the transmission structure for realizing the pressure foot lifting only comprises the cam I and the swing rod and becomes simpler, and meanwhile, the mode of the height change of the contact position can realize the swing of the swing rod at a larger angle because the applied acting force is directly upward. And the connecting rod component is directly fixed with the trimming shaft, so that the trimming shaft can synchronously translate to realize trimming as long as the cam II rotates to push the connecting rod component to translate, and other transmission directions are not changed in the middle, so that the structure of the trimming transmission part is simple. Meanwhile, the structure for realizing the pressure foot lifting and the structure for realizing the thread trimming are respectively positioned at the upper side and the lower side of the motor and are not concentrated in the same area, the distance between the structure and the motor is greatly shortened, the structure is further concise, the problem that the working angle between the first cam and the second cam is staggered is only considered during installation, the problem of space avoidance between other components is not required to be considered, and therefore the failure rate is reduced.

In the driving mechanism for trimming and lifting the presser foot in the flat seaming machine, the contact point of the swing rod and the first cam is close to the edge of the first cam surface.

The contact point of the swing rod and the first cam is arranged close to the edge of the first cam surface, so that the swing angle of the swing rod can be improved, and the motor vertically arranged along can smoothly lift the presser foot by utilizing the first cam surface arranged at the top of the first cam.

In the driving mechanism for trimming and lifting the presser foot in the flat seaming machine, the top of the first cam is provided with a limiting bulge which protrudes upwards from the first cam surface along the edge of the first cam, and the first cam surface is positioned at the inner side of the limiting bulge and is connected with the inner side wall of the limiting bulge.

Because the contact point of the swing rod and the first cam is arranged close to the edge of the first cam surface, and the motor vibrates during working, insufficient contact or contact separation between the first cam surface and the swing rod is easily caused. Therefore, the swing rod can be always limited to be in contact with the cam I by the limiting protrusion, the driving mechanism is ensured to drive the pressure foot lifting work to be stable and the failure rate is reduced by only utilizing the cam surface I arranged at the top to be in contact with the swing rod.

In the driving mechanism for trimming and lifting the presser foot in the flat seaming machine, the contact part of the swing rod and the first cam is a spherical surface.

The first cam surface is a curved surface, and the contact part of the first cam surface and the first swing rod is a spherical surface, so that the first cam surface and the first cam surface are matched more smoothly, and particularly, the resistance of the first cam surface in rotation is smaller, and the first cam surface can jack up the swing rod easily.

In the driving mechanism for trimming and lifting the presser foot in the sewing machine, the top of the first cam is also provided with a first idle stroke surface, one end of the first idle stroke surface is connected with the lowest part of the first cam surface and is consistent in height, the first idle stroke surface is positioned on the inner side of the limiting protrusion and is connected with the inner side wall of the limiting protrusion, and the swing rod abuts against the first idle stroke surface when the second cam drives the trimming shaft to translate.

One end of the first idle stroke surface is connected with the lowest position of the first cam surface, and the height of the first idle stroke surface is consistent with that of the lowest position of the first cam surface, so that the swing rod moves along the first idle stroke surface when the second cam drives the spool to translate, and the rotation of the first cam can not drive the swing rod to swing upwards to avoid interference with the action of lifting the presser foot.

In the thread trimming and presser foot lifting driving mechanism of the flat seaming machine, the connecting rod assembly comprises a first connecting rod, a second connecting rod and a third connecting rod, the first connecting rod and the second connecting rod are arranged in parallel, the third connecting rod is perpendicular to the first connecting rod and is arranged in parallel with a thread trimming shaft, a second cam surface is arranged on the edge of the second cam, one end of the first connecting rod is located on one side of the second cam and abuts against the edge of the second cam, one end of the second connecting rod is fixed with the thread trimming shaft, two ends of the third connecting rod are respectively fixed with the other end of the first connecting rod and the other end of the second connecting rod, a guide seat is fixed on a machine base of the flat seaming machine, and the third connecting rod penetrates through the guide seat.

One end of the first connecting rod is located on one side of the second cam and abuts against the edge of the second cam, one end of the second connecting rod is fixed with the trimming shaft, two ends of the third connecting rod are fixed with the other end of the first connecting rod and the other end of the second connecting rod respectively, the third connecting rod is perpendicular to the first connecting rod and parallel to the trimming shaft, the guide seat can limit the third connecting rod to enable the third connecting rod to only translate along the axis direction of the third connecting rod, when the second cam rotates until the second cam surface contacts with the first connecting rod, thrust can be applied to the first connecting rod, the first connecting rod is fixed with the third connecting rod, the third connecting rod is fixed with the second connecting rod to enable the first connecting rod to translate, and finally the second connecting rod drives the trimming shaft to translate by virtue of the fixation of the second connecting rod and the trimming shaft to complete trimming work. In the whole process, only the rotation of the second cam is converted into the translation change of the whole connecting rod assembly, and no other action direction change exists, so that the structure is simpler, and the failure rate is lower.

In the driving mechanism for trimming and lifting the presser foot in the flat seaming machine, two oppositely arranged mounting seats are fixed on one side of a machine base of the flat seaming machine, a trimming shaft penetrates through the two mounting seats, a reset spring and a limiting block are arranged on the trimming shaft between the two mounting seats, the limiting block is fixed with the trimming shaft, two ends of the reset spring are respectively acted on the limiting block and one of the mounting seats, and one end of a second connecting rod is fixed on the limiting block.

One end of the second connecting rod is fixed to the limiting block, the limiting block is fixed to the first shearing shaft, the connecting rod assembly is fixed to the first shearing shaft, the elastic force exerted on the first shearing shaft by the reset spring can be simultaneously exerted on the connecting rod assembly, therefore, one end of the first connecting rod can always abut against the edge of the second cam, and when the connecting rod assembly translates, the first shearing shaft translates and compresses the reset spring through the limiting block. When the second cam surface of the cam is not contacted with the connecting rod assembly, the elastic force of the return spring is applied to the limiting block, so that the connecting rod assembly and the shear line shaft can simultaneously translate to complete the return.

In the driving mechanism for trimming and lifting the presser foot in the flat seaming machine, the edge of the second cam is also provided with a second idle stroke surface which is concentric with the rotation center of the second cam, one end of the second idle stroke surface is connected with one end of the second cam surface, and the first connecting rod is contacted with the second idle stroke surface when the first cam drives the swing rod to swing upwards.

The second idle stroke surface and the rotation center of the second cam are concentrically arranged, and one end of the second idle stroke surface is in contact with one end of the second cam surface, so that the first connecting rod is in contact with the second idle stroke surface when the first cam drives the swing rod to swing upwards to lift the presser foot, and the rotation of the second cam at the moment can not drive the first connecting rod to move to avoid interference with the action of lifting the presser foot.

In the thread trimming and presser foot lifting driving mechanism in the flat seaming machine, the casing is provided with a control shaft which can drive the thread loosening mechanism in the flat seaming machine to perform thread loosening operation during rotation, one end of the control shaft extends out of one side of the casing, the driving mechanism further comprises a swing arm of which the upper end is fixed on the control shaft, a first connecting arm of which the lower end is fixed on the thread trimming shaft, and a second connecting arm of which the two ends are respectively connected with the first connecting arm and the swing arm, the upper end of the second connecting arm is provided with a strip-shaped movable groove in a penetrating manner, the strip-shaped movable groove is arranged along the vertical direction, and the second connecting arm and the swing arm pass through the strip-shaped movable groove through the rod part and are fixed by a fixing screw in the lower end of the swing arm in a threaded manner.

Through the arrangement, in the process that the connecting rod assembly drives the wire shearing shaft to move under the action of the cam II to complete wire shearing, the connecting arm II moves synchronously along with the wire shearing shaft, and drives the swinging arm to swing to drive the control shaft to rotate to complete wire loosening work under the matching of the connection with the connecting arm I and the fixing of the connecting arm I and the swinging arm through the strip-shaped movable groove and the fixing screw. The driving mechanism can synchronously complete the thread loosening work in the thread trimming process, so that the thread loosening work is not required to be additionally controlled, the structure is further simplified, and the production cost is reduced.

In the thread trimming and presser foot lifting driving mechanism of the flat seaming machine, one side of the machine shell is provided with a mounting groove communicated with the inner cavity of the machine shell, the mounting groove and the thread trimming shaft are positioned on the same side, the motor is arranged at the mounting groove, the upper end and the lower end of the shell of the motor are respectively connected with the mounting supports, and the two mounting supports are fixed on the machine shell where the notch of the mounting groove is positioned.

Through the setting of mounting groove and the use of cooperation installing support for the motor can set up and fix along vertical direction, can make the wholeness of flat seaming machine better like this. And moreover, the arrangement of the mounting groove can ensure that the upper end of the rotating shaft of the motor can be directly close to the presser foot shaft, and the distance between the first cam and the presser foot shaft is shortened, so that the motor arranged in the vertical direction can complete transmission only through the first cam surface arranged at the top of the cam and the two parts of the swing rod fixed on the presser foot shaft, the structure is simplified, and the failure rate is reduced.

Compared with the prior art, the driving mechanism for trimming and lifting the presser foot in the flat seaming machine has the following advantages:

1. the motor is arranged along the vertical direction, and the swing rod is directly driven to swing by combining the height change of the contact position of the first cam surface arranged at the top of the first cam and the swing rod, so that the first cam is closer to the position of a thread cutting shaft, and the structure of the presser foot lifting is simpler as only the first cam and the swing rod form;

2. the connecting rod assembly directly fixed with the trimming shaft is arranged, the connecting rod assembly is pushed to translate only by the rotation of the cam II, the trimming shaft can be enabled to translate synchronously to achieve trimming, other transmission directions are not changed in the middle, and the structure of the trimming transmission part is concise;

3. the structure for realizing the presser foot lifting and the structure for realizing the thread cutting are respectively positioned at the upper side and the lower side of the motor and are not concentrated in the same area, so that the distance between the structure and the motor is greatly shortened, the structure is further concise, the problem of working angle staggering between the first cam and the second cam is only considered during installation, and the problem of space avoidance between other components is not required to be considered, so that the failure rate is reduced;

4. the thread loosening work can be finished simultaneously when the thread is cut, so that the thread loosening work does not need to be controlled additionally, the structure is further simplified, and the production cost is reduced.

Drawings

FIG. 1 is a schematic view of a flat seaming machine.

FIG. 2 is a partially exploded schematic view of the flat seaming machine.

FIG. 3 is a schematic view at a machine base in the flat seaming machine.

Fig. 4 is a schematic view of the present flat seaming machine at the motor of the thread trimming and presser foot lifting drive mechanism.

FIG. 5 is a schematic view of the drive mechanism for trimming and raising the presser foot in the flat seaming machine.

FIG. 6 is a schematic view of the cooperation of the first cam and the swing link

Fig. 7 is a structural schematic diagram of the first cam.

FIG. 8 is another perspective view of the drive mechanism for trimming and raising the presser foot of the flat seaming machine.

FIG. 9 is a schematic bottom view of the second cam and the linkage assembly.

In the figure, 1, a housing; 1a, mounting grooves; 2. a machine base; 3. a presser foot shaft; 4. scissors; 5. a transmission rod; 6. a mounting seat; 7. a thread cutting shaft; 8. a return spring; 9. a limiting block; 10. a motor; 10a, a rotating shaft; 11. mounting a bracket; 11a, a first frame body; 11a1, connecting sheet; 11b, a second frame body; 11b1, tab; 12. a first cam; 12a, a first cam surface; 12b, a first idle stroke surface; 12c, a limiting bulge; 13. a swing rod; 13a, a bending part; 14. a ball head screw; 15. a second cam; 15a, a second cam surface; 15b, a second idle stroke surface; 16. a connecting rod assembly; 16a, a first connecting rod; 16b, a second connecting rod; 16c, a third connecting rod; 17. a guide seat; 18. a bearing; 19. a control shaft; 20. swinging arms; 21. a first connecting arm; 22. a second connecting arm; 22a, a strip-shaped movable groove; 23. and fixing the screw.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

As shown in fig. 1, 2 and 3, a driving mechanism for thread cutting and presser foot lifting in a flat seaming machine, the flat seaming machine includes a machine base 2 and a machine shell 1 fixed on the machine base 2, a presser foot shaft 3 connected with the presser foot (not shown in the figure) and capable of lifting the presser foot when rotating is arranged in the machine shell 1, a reset torsion spring (not shown in the figure) acting on the presser foot shaft 3 is arranged on the presser foot shaft 3, the presser foot shaft 3 can be lifted when rotating, a transmission structure between the presser foot shaft 3 and the presser foot and a specific arrangement mode of the reset torsion spring on the presser foot shaft 3 can refer to a driving device for thread cutting and presser foot lifting on a sewing machine with patent application number 201920042424.2 mentioned in the background technology. The upper side surface of the base 2 is provided with a pair of scissors 4 capable of translating and a transmission rod 5 with one end connected with the scissors 4, the middle part of the transmission rod 5 is hinged to the upper side surface of the base 2, the side part of the base 2 is provided with two oppositely arranged mounting seats 6, the wire cutting shaft 7 penetrates through the two mounting seats 6, one end of the wire cutting shaft 7 is connected with the other end of the transmission rod 5, the wire cutting shaft 7 positioned between the two mounting seats 6 is sleeved with a return spring 8, a limiting block 9 is further fixed on the wire cutting shaft 7 of the part, two ends of the return spring 8 are respectively used on the limiting block 9 and the mounting seat 6 far away from the transmission rod 5, and when the wire cutting shaft 7 moves in the direction overcoming the elasticity of the return spring 8, the transmission rod 5 can be pulled to swing and the scissors 4 can be pushed to move forwards to realize wire cutting.

As shown in fig. 1, fig. 2 and fig. 4, the driving mechanism includes a motor 10 fixed on a casing 1 and a driving member fixed on a rotating shaft 10a of the motor 10, wherein a mounting groove 1a communicated with an inner cavity of the casing 1 is formed in one side of the casing 1, the mounting groove 1a and a trimming shaft 7 are located on the same side, the mounting groove 1a is a straight groove, the motor 10 is located at the mounting groove 1a, mounting brackets 11 are respectively connected to upper and lower ends of a housing of the motor 10, and the two mounting brackets 11 are fixed on the casing 1 where a notch of the mounting groove 1a is located. Specifically, each of the two mounting brackets 11 includes a first bracket 11a fixed to a corresponding end of the housing of the motor 10 and a second bracket 11b connected to the first bracket 11a, the first bracket 11a has a connecting piece 11a1, the second bracket 11b is U-shaped, the connecting piece 11a1 is fixed to the inner side of the second bracket 11b, two ends of the second bracket 11b have lugs 11b1, and the two lugs 11b1 are located at two sides of the mounting groove 1a and are respectively fixed to the housing 1.

As shown in fig. 5, 6 and 7, the rotating shaft 10a of the motor 10 has an upper end and a lower end, the upper end of the rotating shaft 10a of the motor 10 is close to the presser foot shaft 3, the driving member includes a first cam 12 fixed on the upper end of the rotating shaft 10a of the motor 10, the driving mechanism further includes a rocker 13 fixed on the presser foot shaft 3, the top of the first cam 12 has a first cam surface 12a, the first cam surface 12a is arranged around the central line of the rotating shaft 10a of the motor 10, and the rocker 13 abuts against the first cam surface 12a and can push the rocker 13 to swing upwards through the first cam surface 12a when the first cam 12 rotates. The top of the first cam 12 is also provided with a first idle stroke surface 12b, the first idle stroke surface 12b is arranged around the central line of the rotating shaft 10a of the motor 10, one end of the first idle stroke surface 12b is connected with the lowest point of the first cam surface 12a and is a first idle stroke surface 12b with the same height, the plane of the first idle stroke surface 12b is vertical to the rotating shaft 10a of the motor 10, and the swing rod 13 can be kept still when the first cam 12 rotates but the swing rod 13 is in contact with the first idle stroke surface 12 b. Specifically, the contact part of the swing rod 13 and the first cam 12 is a spherical surface, the contact point of the swing rod 13 and the first cam 12 is close to the edge of the first cam surface 12a, the top of the first cam 12 is provided with a limit protrusion 12c protruding upwards along the edge, and the first cam surface 12a and the first idle stroke surface 12b are both positioned on the inner side of the limit protrusion 12c and are both connected with the inner side wall of the limit protrusion 12 c. In the embodiment, the end of the swing link 13 has a horizontal bent part 13a, the bent part 13a is fixed with the ball screw 4, and the ball head of the ball screw 4 abuts against the top of the cam one 12.

Further, as shown in fig. 3, 8 and 9, the driving member further includes a second cam 15 fixed to a lower end of the rotating shaft 10a of the motor 10, and the driving mechanism further includes a link assembly 16 connected to the wire cutting shaft 7, and when the second cam 15 rotates, the link assembly 16 can drive the wire cutting shaft 7 to translate (specifically, see the action principle of wire cutting below). Specifically, the connecting rod assembly 16 includes a first connecting rod 16a, a second connecting rod 16b and a third connecting rod 16c, wherein the first connecting rod 16a and the second connecting rod 16b are arranged in parallel, the third connecting rod 16c is perpendicular to the first connecting rod 16a and parallel to the shear line shaft 7, two ends of the third connecting rod 16c are respectively fixed to one end of the first connecting rod 16a and one end of the second connecting rod 16b, a guide seat 17 is fixed on the machine base 2, the third connecting rod 16c penetrates through the guide seat 17, and the other end of the second connecting rod 16b is fixed to a limit block 9 of the shear line shaft 7. The edge of the second cam 15 is provided with a second cam surface 15a, the other end of the first connecting rod 16a is positioned at one side of the second cam 15 and is always abutted against the edge of the second cam surface 15a under the action of the elastic force of the return spring 8, in the embodiment, the bearing 18 is connected to one end of the first connecting rod 16a positioned at one side of the second cam 15, and the bearing 18 is in contact with the edge of the second cam surface 15a, so that the bearing 18 can reduce abrasion. The edge of the second cam 15 is also provided with a second idle stroke surface 15b which is concentric with the rotation center of the second cam, one end of the second idle stroke surface 15b is connected with one end of the second cam surface 15a, and the first connecting rod 16a is kept still when the second cam 15 rotates but the bearing 18 is contacted with the second idle stroke surface 15 b.

In the initial state, the contact point of the rocker 13 and the first cam 12 is located at the connection position of the lowest point of the first cam surface 12a and the first idle stroke surface 12b, and the contact point of the connecting rod assembly 16 and the second cam 15 is located at the connection position of the second cam surface 15a and the second idle stroke surface 15 b. When the presser foot needs to be lifted, the rotating shaft 10a of the motor 10 rotates towards one direction (clockwise in the embodiment), the contact point between the cam first 12 and the swing rod 13 changes from the lowest point of the cam surface first 12a to the highest point of the cam surface first 12a along with the rotation of the cam first 12, and in the process, the swing rod 13 is stressed to swing upwards, so that the presser foot shaft 3 rotates and the presser foot is lifted upwards. During the lifting process of the presser foot, the second cam 15 is also in rotation and the connecting rod assembly 16 is kept still through the contact of the connecting rod assembly 16 and the second idle stroke surface 15 b.

When the wire cutting is needed, the rotating shaft 10a of the motor 10 rotates counterclockwise, the contact point between the cam second 15 and the swing rod 13 returns to the connection point of the cam second 15a and the idle stroke second 15b along with the rotation of the cam second 15, and then the cam second 15a at the edge of the cam second 15 starts to contact with the connecting rod first 16a along with the further rotation of the cam second 15. Because one end of the second connecting rod 16b is fixed with the shear line shaft 7, two ends of the third connecting rod 16c are respectively fixed with the other end of the first connecting rod 16a and the other end of the second connecting rod 16b, the third connecting rod 16c is perpendicular to the first connecting rod 16a and parallel to the shear line shaft 7, the guide seat 17 can limit the third connecting rod 16c to only translate along the axial direction so as to ensure that the whole connecting rod assembly 16 can only translate along the axial direction of the third connecting rod 16c, so that when the second cam 15 rotates until the second cam surface 15a contacts with the first connecting rod 16a, a thrust is exerted on the first connecting rod 16a, the whole connecting rod assembly 16 is translated by the fixation of the first connecting rod 16a and the third connecting rod 16c and the fixation of the third connecting rod 16c and the second connecting rod 16b, finally, the connecting rod assembly 16 drives the wire cutting shaft 7 to move in the direction of overcoming the elastic force of the return spring 8 by virtue of the fixation of the second connecting rod 16b and the wire cutting shaft 7 so as to drive the scissors 4 to move to complete wire cutting. In the process, the first cam 12 also rotates in the same direction as the second cam 15, the highest point of the first cam surface 12a moves away from the lower part of the swing rod 13 along with the rotation of the first cam 12 until the lowest point of the first cam surface 12a is positioned below the swing rod 13, and meanwhile, the presser foot shaft 3 rotates under the action of the reset torsion spring and drives the swing rod 13 to swing downwards and always contact with the first cam surface 12a, and then becomes the idle stroke surface one 12b to contact with the swing rod 13.

Further, as shown in fig. 1, fig. 2 and fig. 8, the flat seaming machine further includes a thread releasing mechanism, a control shaft 19 capable of driving the thread releasing mechanism to release threads is arranged on the machine casing 1, one end of the control shaft 19 extends out of one side of the machine casing 1 where the mounting groove 1a is located, the driving mechanism further includes a swing arm 20 whose upper end is fixed on the control shaft 19, a first connecting arm 21 whose lower end is fixed on the thread cutting shaft 7, and a second connecting arm 22 whose two ends are respectively connected with the first connecting arm 21 and the swing arm 20, the upper end of the second connecting arm 22 is provided with a strip-shaped movable groove 22a in a penetrating manner, the strip-shaped movable groove 22a is arranged along the vertical direction, and the second connecting arm 22 and the swing arm 20 are fixed by a fixing screw 23 whose rod portion penetrates through the strip-shaped movable groove 22a and is in the lower end of the swing arm 20 through a threaded connection.

In the process that the connecting rod assembly 16 is squeezed by the cam surface two 15a to drive the wire cutting shaft 7 to move to cut the wire, the connecting arm two 22 moves synchronously with the wire cutting shaft 7, and drives the swing arm 20 to swing to drive the control shaft 19 to rotate to finish the wire loosening work under the connection with the connecting arm one 21 and the matching of the connecting arm one 21 and the swing arm 20 which are fixed with the fixing screw 23 through the strip-shaped movable groove 22 a.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.