CN209243339U

CN209243339U - A kind of the automatic shearing mechanism and sewing machine of sewing machine

Info

Publication number: CN209243339U
Application number: CN201822017752.5U
Authority: CN
Inventors: 何清
Original assignee: Zhejiang Maqi Sewing Machine Co Ltd
Current assignee: Meiji Technology Group Co ltd
Priority date: 2018-12-03
Filing date: 2018-12-03
Publication date: 2019-08-13
Anticipated expiration: 2028-12-03

Abstract

The utility model belongs to sewing device technical field, is related to the automatic shearing mechanism and sewing machine of a kind of sewing machine, which solve existing automatic shearing mechanisms to be easy the technical problems such as stuck.This automatic shearing mechanism includes the lower axle being parallel to each other and shear spool, and lower axle is rotatably dispose on the bottom plate of sewing machine, and lower axle is fixed with trimming cam, and trimming cam has trimming section and forces back knife section；Shear spool is rotatably dispose on bottom plate, is fixed on shear spool and is forced back knife crank, forces back have boss on knife crank；Trimming driving crank is also arranged on shear spool, trimming, which drives, has sliding slot on crank, boss is slidably connected with the sliding slot；The left end of shear spool is also connected with trimming moving knife component, and the right end sliding sleeve of shear spool is equipped with driver plate, and the driving source for being able to drive the driver plate towards trimming driving crank direction sliding is fixed on the bottom plate of sewing machine.The utility model can effectively avoid phenomena such as stuck.

Description

A kind of the automatic shearing mechanism and sewing machine of sewing machine

Technical field

The utility model belongs to sewing device technical field, is related to the automatic shearing mechanism and sewing machine of a kind of sewing machine.

Background technique

In the thread cutting mechanism of existing sewing machine, trimming component needs to realize following functions: trimming position and non-trimming position Handoff functionality, forced resetting function etc..

A kind of trimming driving assembly, thread cutting mechanism as disclosed in 108385293 A of China patent CN and sewing machine, power Transmission mechanism includes shear spool, trimming driving crank, drive shaft and driving cam；Forced resetting arm is fixed on shear spool；It cuts Line driving crank is set on shear spool, and is slidably connected by being slidably connected structure with shear spool, and drive is fixed in drive shaft Moving cam, driving cam includes forced resetting portion and driving portion；Trimming drives driving portion of the crank in trimming with driving cam Profile face contact；Forced resetting portion is opposite with forced resetting arm position, and when normal reset non-for shear spool passes through reset portion Contact with reset arm carries out forced resetting.

The specific structure that wherein trimming drives crank to be slidably connected with shear spool is as follows: such as above-mentioned patent specification the 52nd Duan Suoshu is provided with axial groove on the right side of fixing sleeve, sliding pin is equipped on trimming driving crank, and sliding pin and axial groove slide Cooperation, to realize being slidably connected for shear spool.And as other alternative solutions, such as the 57th section of above-mentioned patent specification, 58 Duan Suoshu, sliding pin and axial groove are slidably matched, and the mode of plane and plane cooperation also can be used, sliding pin can also be arranged On fixing sleeve or reset arm, and axial groove correspondingly is opened up on trimming driving crank.

But above-mentioned thread cutting mechanism still has the disadvantage that

1, since the assembly space in sewing machine is smaller, and power transfer mechanism is during installation, needs first by reseting spring sleeve It is located on the right side of fixing sleeve, then trimming driving crank is set on shear spool, and pass through the sliding pin on trimming driving crank Reset spring is plugged in the axial groove on the right side of fixing sleeve, and reset spring not only will affect assembly sight, can also make assembly space It is smaller, to improve assembly difficulty, reduce assembly efficiency；

2, the electromagnet in above-mentioned patent is the iron core band by electromagnet when driving trimming driving crank to horizontally slip Dynamic ejector pin is mobile, and the side wall of ejector pin and trimming driving crank mutually reclines to drive trimming driving crank sliding.Trimming driving is bent The side wall local pressure of handle, the axis for deviateing shear spool farther out, exist and are easy stuck risk.

Utility model content

The purpose of this utility model is the presence of the above problem in view of the prior art, proposes a kind of automatic shearing of sewing machine Line mechanism, the technical problem to be solved by the utility model is to how to reduce trimming driving crank stuck risk, reduce at This.

The purpose of this utility model can be realized by the following technical scheme:

A kind of automatic shearing mechanism of sewing machine, which is characterized in that the automatic shearing mechanism includes being parallel to each other down Axis and shear spool, the lower axle are rotatably dispose on the bottom plate of sewing machine, and trimming cam is fixed in the lower axle, the trimming The outer peripheral surface of cam has trimming section and forces back knife section；The shear spool is rotatably dispose on the bottom plate of sewing machine, described to cut Knife crank can be returned with the pressure for forcing back knife section mutually to recline of the trimming cam by being fixed on spool, described to force back knife bent There is radially projecting boss on handle；It is also arranged with trimming driving crank on the shear spool and the two is slidably matched, it is described Trimming, which drives, has the sliding slot parallel with the shear spool on crank, the boss for forcing back knife crank and sliding slot sliding connect It connects；The left end of the shear spool is also connected with trimming moving knife component, and the right end of the shear spool is arranged with driver plate and the two is sliding It is dynamic to cooperate, the driving source for being able to drive the driver plate towards trimming driving crank direction sliding, institute are fixed on the bottom plate of sewing machine State driver plate be able to drive trimming driving crank slide axially, make trimming driving crank end and trimming cam trimming section It is in contact.

Its working principles are as follows: when normal sewing, the lower axle rotation of sewing machine, although the trimming cam in lower axle exists always Rotation, but be not in contact with the trimming driving crank on shear spool, shear spool will not be swung, and then it is dynamic to respond trimming Knife assembly carries out trimming；And when needing trimming, driving source drives driver plate to slide towards trimming driving crank direction, to drive Trimming driving crank slides axially, and so that the end of trimming driving crank is in contact with the trimming section of trimming cam, is rotating Trimming cam is able to drive trimming driving crank-swinging, and then forces back knife crank to be put by the cooperation of sliding slot and boss drive Dynamic, to make shear spool synchronous hunting, the final moving knife for driving shear spool end, which is swung, realizes trimming.It is cut since driver plate is set to On spool, when driver plate reclines with trimming driving crank, trimming drives the forced area of crank larger and uniform, and substantially About the axisymmetrical of shear spool, so that being not susceptible to stuck phenomenon when trimming driving crank sliding；And with prior art phase Than the part of mechanism is more simplified, and production cost can be reduced.

In a kind of automatic shearing mechanism of above-mentioned sewing machine, offered on the bottom plate parallel with the shear spool Strip groove, the driver plate include that vertical and the sliding part being fixedly connected with and pushing part, the sliding part are slidably connected with strip groove, Through-hole one is offered on the pushing part, the shear spool passes through through-hole one and the two does not contact, and the sliding part can pass through Pushing part is set to drive crank mutually to recline with the trimming along strip groove sliding.Design has a strip groove and sliding part, and pushing part with Shear spool does not contact, it is ensured that the glide direction of sliding part is axial parallel with shear spool, itself sends out when driver plate being avoided to slide Raw stuck phenomenon, it is also ensured that pushing part has biggish forced area when reclining with trimming driving crank.

In a kind of automatic shearing mechanism of above-mentioned sewing machine, as a kind of scheme, being provided in the driving source can The mandrel being axially moveable, the end of the mandrel are provided with the connector that can mutually recline with the driver plate.Mandrel is mobile Can be mobile with follower link, and then drive driving member mobile by connector, it is final to drive trimming driving crank mobile.

In a kind of automatic shearing mechanism of above-mentioned sewing machine, alternatively, the driving source and driver plate Between there is loose ends seat, the loose ends seat is movably set on bottom plate, and axially displaceable core is provided in the driving source Axis, the end of the mandrel are provided with the connector that can mutually recline with the loose ends seat right side, set on the left of the loose ends seat It is equipped with trundle, there is the promotion seat that can mutually recline with the left side of the trundle on the driver plate.Mandrel movement can band Follower link is mobile, thus drive loose ends seat mobile, then cooperate by the promotion seat on the trundle and driver plate on loose ends seat, It drives driver plate mobile, and then drives trimming driving crank mobile.

In a kind of automatic shearing mechanism of above-mentioned sewing machine, the trimming driving crank includes spaced left side Arm and right arm, through-hole two is offered on the left side arm and right arm, and the shear spool passes through through-hole two and is slidably matched； It is connected between the left side arm and right arm two by transverse arm, the sliding slot is opened on transverse arm along axial direction.

In a kind of automatic shearing mechanism of above-mentioned sewing machine, stationary knife, the stationary knife are fixed on the bottom plate of sewing machine Positioned at the left end of lower axle；The trimming moving knife component includes trimming crank, trimming connecting rod and moving knife, one end of the trimming crank It is fixedly connected with the left end of the shear spool, the both ends of the trimming connecting rod other end and moving knife with the trimming crank respectively It is hinged.Shear spool swing can drive trimming crank synchronous hunting, and then drive moving knife to swing by trimming connecting rod, match with stationary knife It closes and realizes trimming.

In a kind of automatic shearing mechanism of above-mentioned sewing machine, fixing sleeve is fixed on the bottom plate of sewing machine, it is described to cut Spool passes through the fixing sleeve, and reduction torsion spring is arranged on the fixing sleeve, and the effect end of the reduction torsion spring and the trimming are bent Handle connection or against.Shear spool is swung, and is driven trimming crank-swinging and is swung moving knife around lower axle by the effect of trimming connecting rod Realize trimming；After trimming, trimming driving crank no longer mutually reclines with the trimming section of trimming cam, and trimming crank can be multiple It is resetted under the action of the torsional spring of position, to carry out next trimming.

In a kind of automatic shearing mechanism of above-mentioned sewing machine, the right end of the fixing sleeve is fixed with retaining ring, the gear It is provided with reseting pressuring spring between circle and trimming driving crank, the reseting pressuring spring is sheathed on shear spool；When the reseting pressuring spring When in reset state, the trimming driving crank is located at the right side of the trimming cam.When trimming, driving source overcomes reset to press The elastic force of spring makes trimming driving crank move to left to recline with trimming cam and realize trimming；After trimming, trimming drives crank can be It resets to move to right under the action of reseting pressuring spring and not be in contact with trimming cam.

A kind of sewing machine, which is characterized in that the sewing machine includes above-mentioned automatic shearing mechanism.

Compared with prior art, the utility model has the advantage that

Due to driver plate be set to shear spool on, when driver plate and trimming driving crank recline when, trimming drive crank by Power area is larger and uniform, and is generally concerned with the axisymmetrical of shear spool, so that being not susceptible to when trimming driving crank sliding Stuck phenomenon.

Detailed description of the invention

Fig. 1 is the axonometric drawing of this automatic shearing mechanism in embodiment one.

Structural schematic diagram when Fig. 2 is the non-trimming of this automatic shearing mechanism in embodiment one.

Structural schematic diagram when Fig. 3 is this automatic shearing mechanism trimming in embodiment one.

Fig. 4 is the positional diagram in embodiment one between each component.

Fig. 5 is the cooperation figure in embodiment one between trimming cam and trimming driving crank.

Fig. 6 is the structural schematic diagram in embodiment one between this driver plate and shear spool.

Fig. 7 is the structural schematic diagram of this bottom plate in embodiment one.

Fig. 8 is the structural schematic diagram of this driver plate in embodiment one.

Fig. 9 is the structural schematic diagram that knife crank is returned in this pressure in embodiment one.

Figure 10 is the structural schematic diagram of this trimming driving crank in embodiment one.

Figure 11 is the structural schematic diagram of this bottom plate in embodiment two.

Figure 12 is the structural schematic diagram of this loose ends seat in embodiment two.

Figure 13 is the structural schematic diagram of this driver plate in embodiment two.

In figure, 1, lower axle；2, shear spool；3, bottom plate；4, trimming cam；5, trimming section；6, knife section is forced back；7, it forces back Knife crank；8, boss；9, trimming drives crank；10, sliding slot；11, trimming moving knife component；12, driver plate；13, driving source；14, Strip groove；15, sliding part；16, pushing part；17, through-hole one；18, mandrel；19, connector；20, loose ends seat；21, trundle； 22, seat is pushed；23, left side arm；24, right arm；25, through-hole two；26, transverse arm；27, stationary knife；28, trimming crank；29, trimming connects Bar；30, moving knife；31, fixing sleeve；32, reduction torsion spring；33, retaining ring；34, reseting pressuring spring.35, roller；36, knife portion is forced go back to； 37, movable knife rack.

Specific embodiment

It is specific embodiment of the utility model and in conjunction with attached drawing below, the technical solution of the utility model is made further Description, but the utility model is not limited to these examples.

As shown in Figure 1, Figure 2, Figure 3 shows, this automatic shearing mechanism includes the lower axle 1 being parallel to each other and shear spool 2, and 1 turn of lower axle It is dynamic to be set on the bottom plate 3 of sewing machine, and trimming cam 4 is fixed in the lower axle 1, the outer peripheral surface of trimming cam 4 has trimming Section 5 and forces back knife section 6.In the present embodiment, trimming cam 4 is preferably two-piece type structure, is divided into trimming body and forces back cutter hub, The two, which can be an integral structure, can also be used fastener and is fixedly connected with, and in order to fix trimming cam 4, can force back body portion Design screw.As other schemes, three-chip type structure is can also be used in trimming cam 4, in trimming body and forces back to set between cutter hub It counts for the fixed part fixed with 1 phase of lower axle.

As shown in Figure 1, Figure 2, shown in Fig. 3, Fig. 9, shear spool 2 is rotatably dispose on the bottom plate 3 of sewing machine, fixed on shear spool 2 Knife crank 7 can be returned with the pressure for forcing back 6 phase of knife section to recline of trimming cam 4 by having.In the present embodiment, knife crank 7 is forced back It radially extends to be formed and forces go back to knife portion 36.Force back that also there is radially projecting boss 8 on knife crank 7；On shear spool 2 also It is arranged with trimming driving crank 9 and the two is slidably matched, trimming, which drives, has the sliding slot 10 parallel with shear spool 2 on crank 9, by force The boss 8 and the sliding slot 10 for making back knife crank 7 are slidably connected.Specifically, as shown in Figure 10, between trimming driving crank 9 includes Every offering through-hole 2 25 on the left side arm 23 and right arm 24 of setting, left side arm 23 and right arm 24, shear spool 2 passes through logical It hole 2 25 and is slidably matched；It is connected between left side arm 23 and right arm 24 2 by transverse arm 26, sliding slot 10 is opened in along axial direction On transverse arm 26, there is the roller 35 that can be reclined with 4 phase of trimming cam on right side wall 24.

Preferably, as shown in figure 5, being forced back when trimming moment trimming cam 4 lifts roller 35 and reaches the limit of Knife crank 7 forces back to exist between the pressure of knife portion 36 and trimming cam 4 time knife section 6 distance m, and m > 0, if having cut line Fail back knife, i.e., when reduction torsion spring 32 fails to reset trimming crank 28, then the meeting of knife section 6 and pressure are returned in the pressure of trimming cam 4 The pressure for returning knife crank 7 goes back to knife portion 36 and contacts and finally reset trimming moving knife component 11 by movement transmitting.

In order to realize trimming, as shown in Figure 1, Figure 2, Figure 3 shows, the left end of shear spool 2 is also connected with trimming moving knife component 11, this In embodiment, stationary knife 27 is fixed on the bottom plate 3 of sewing machine, stationary knife 27 is located at the left end of lower axle 1；Trimming moving knife component 11 includes Trimming crank 28, trimming connecting rod 29, moving knife 30 and movable knife rack 37, one end of trimming crank 28 and the left end of shear spool 2 are fixedly connected with, The both ends of trimming connecting rod 29 are hinged with the other end of trimming crank 28 and movable knife rack 37 respectively, and moving knife 30 is fixed on movable knife rack On 37.As other schemes, stationary knife can also be omitted, by trimming moving knife component 11 be designed as two sets can around the moving knife that lower axle 1 is swung, Trimming connecting rod and trimming crank drive corresponding trimming crank, trimming connecting rod and the movement of trimming moving knife by the swing of lower axle 1, Realize trimming.

As shown in Figure 1, Figure 2, Figure 3 shows, the right end of shear spool 2 is arranged with driver plate 12 and the two is slidably matched, sewing machine The driving source 13 for being able to drive the driver plate 12 towards trimming driving 9 direction of crank sliding is fixed on bottom plate 3, driver plate 12 can It drives trimming driving crank 9 to slide axially, the end of trimming driving crank 9 is made to be in contact with the trimming section 5 of trimming cam 4.

In the present embodiment, the strip groove 14 parallel with shear spool 2 is offered on bottom plate 3, driver plate 12 includes vertical and phase Connected sliding part 15 and pushing part 16, sliding part 15 are slidably connected with strip groove 14, and through-hole 1 is offered on pushing part 16, Shear spool 2 passes through through-hole 1 and the two does not contact, and sliding part 15 can be by making pushing part 16 and cutting along the sliding of strip groove 14 Line driving 9 phase of crank reclines.And there are many type of driving source 1, can be electromagnet, cylinder, linear motor etc..Specifically, originally In embodiment, driving source 1 is preferably electromagnet, is provided with axially displaceable mandrel 18, the end of mandrel 18 in driving source 13 Portion is provided with the connector 19 that can be reclined with 12 phase of driver plate.Certainly, mandrel 18 is directly connected or reclines with driver plate 12 It can.

It resets to realize to carry out next trimming, as shown in Figure 1, Figure 2, Figure 3 shows, is fixed on the bottom plate 3 of sewing machine Fixing sleeve 31, shear spool 2 pass through the fixing sleeve 31, are arranged with reduction torsion spring 32, the effect end of reduction torsion spring 32 on fixing sleeve 31 Connect with trimming crank 28 or against.The right end of fixing sleeve 31 is fixed with retaining ring 33, sets between retaining ring 33 and trimming driving crank 9 It is equipped with reseting pressuring spring 34, reseting pressuring spring 34 is sheathed on shear spool 2；When reseting pressuring spring 34 is in reset state, trimming driving Crank 9 is located at the right side of trimming cam 4.

Do not interfered between each component when in order to guarantee trimming it is stuck, as shown in figure 4, L0 be driving source 13 output end Range is moved to left, L1 is the distance between driving source 13 and shear spool 2, and L2 is the length for the sliding slot 10 that trimming drives on crank 9 Degree, L3 are the width for forcing go back to knife portion 36 forced back on knife crank 7, and L4 is sliding slot 10 and forces back between 36 right side of knife portion Distance, wherein L1 > 0 guarantees that shear spool 2 will not be moved to the left under the action of driving source 13, wherein L4 > 0, guarantees sliding slot 10 will not collide with knife portion 36 is forced go back to, wherein L2 > L0+L3+2*L4, and guarantee forces back knife portion 36 can be in sliding slot 10 freely Sliding.

Embodiment two:

The present embodiment is roughly the same with embodiment one, the difference is that, as shown in Figure 11, Figure 12, Figure 13, the present embodiment In, there is loose ends seat 20, loose ends seat 20 is movably set on bottom plate 3, sets in driving source 13 between driving source 13 and driver plate 12 It is equipped with axially displaceable mandrel 18, the end of mandrel 18 is provided with the connector that can mutually recline with 20 right side of loose ends seat 19, the left side of loose ends seat 20 is provided with trundle 21, and having on driver plate 12 can push away with what the left side of trundle 21 mutually reclined Dynamic seat 22.

The utility model additionally provides a kind of sewing machine including above-mentioned automatic shearing mechanism.

The working principle of the utility model is as follows: when normal sewing, the lower axle 1 of sewing machine is rotated, and the trimming in lower axle 1 is convex Although wheel 4 is rotating always, it is not in contact with the trimming driving crank 9 on shear spool 2, shear spool 2 will not be swung, into Trimming is carried out without responding trimming moving knife component 11；And when needing trimming, driving source 13 drives driver plate 12 to drive towards trimming Dynamic 9 direction of crank sliding keeps the end of trimming driving crank 9 and trimming convex so that trimming driving crank 9 be driven to slide axially The trimming section 5 of wheel 4 is in contact, and the trimming cam 4 being rotating is able to drive trimming driving crank 9 and swings, and then passes through sliding slot 10 Cooperation drive with boss 11 forces back knife crank 7 to swing, thus make 2 synchronous hunting of shear spool, it is final to drive 2 end of shear spool Moving knife 30 swing realize trimming.

The specific embodiments described herein are merely examples of the spirit of the present invention.The utility model institute Belonging to those skilled in the art can make various modifications or additions to the described embodiments or using similar Mode substitute, but without departing from the spirit of the present application or beyond the scope of the appended claims.

Claims

1. a kind of automatic shearing mechanism of sewing machine, which is characterized in that the automatic shearing mechanism includes the lower axle being parallel to each other (1) it is rotatably dispose on the bottom plate (3) of sewing machine with shear spool (2), the lower axle (1), and is fixed with trimming in the lower axle (1) Cam (4), the outer peripheral surface of the trimming cam (4) have trimming section (5) and force back knife section (6)；Shear spool (2) rotation It is set on the bottom plate (3) of sewing machine, knife can be returned with the pressure of the trimming cam (4) by being fixed on the shear spool (2) Knife crank (7) are gone back in the pressure that section (6) mutually reclines, described to force back have radially projecting boss (8) on knife crank (7)；Institute It states and is also arranged with trimming driving crank (9) on shear spool (2) and the two is slidably matched, have in trimming driving crank (9) The sliding slot (10) parallel with the shear spool (2), the boss (8) for forcing go back to knife crank (7) and the sliding slot (10) sliding connect It connects；The left end of the shear spool (2) is also connected with trimming moving knife component (11), and the right end of the shear spool (2) is arranged with transmission Plate (12) and the two is slidably matched, be fixed on the bottom plate (3) of sewing machine be able to drive the driver plate (12) driven towards trimming it is bent The driving source (13) of handle (9) direction sliding, the driver plate (12) are able to drive trimming driving crank (9) and slide axially, make The end of trimming driving crank (9) is in contact with the trimming section (5) of trimming cam (4).

2. the automatic shearing mechanism of sewing machine according to claim 1, which is characterized in that offered on the bottom plate (3) The strip groove (14) parallel with the shear spool (2), the driver plate (12) include sliding part (15) that is vertical and being fixedly connected with and Pushing part (16), the sliding part (15) are slidably connected with strip groove (14), offer through-hole one on the pushing part (16) (17), the shear spool (2) passes through through-hole one (17) and the two does not contact, and the sliding part (15) can be by along strip groove (14) sliding makes pushing part (16) drive crank (9) mutually to recline with the trimming.

3. the automatic shearing mechanism of sewing machine according to claim 2, which is characterized in that be arranged on the driving source (13) Have axially displaceable mandrel (18), the end of the mandrel (18) is provided with and can mutually recline with the driver plate (12) Connector (19).

4. the automatic shearing mechanism of sewing machine according to claim 2, which is characterized in that the driving source (13) and transmission There are loose ends seat (20) between plate (12), the loose ends seat (20) is movably set on bottom plate (3), sets on the driving source (13) It is equipped with axially displaceable mandrel (18), the end of the mandrel (18) is provided with can be with phase on the right side of the loose ends seat (20) The connector (19) to recline is provided with trundle (21) on the left of the loose ends seat (20), has energy on the driver plate (12) The promotion seat (22) that enough left sides with the trundle (21) mutually recline.

5. according to the automatic shearing mechanism of sewing machine described in Claims 2 or 3 or 4, which is characterized in that the trimming driving is bent Handle (9) includes spaced left side arm (23) and right arm (24), is opened up in the left side arm (23) and right arm (24) There is through-hole two (25), the shear spool (2) passes through through-hole two (25) and is slidably matched；The left side arm (23) and right arm (24) It is connected between two by transverse arm (26), the sliding slot (10) is opened on transverse arm (26) along axial direction.

6. according to the automatic shearing mechanism of sewing machine described in Claims 2 or 3 or 4, which is characterized in that the bottom plate of sewing machine (3) it is fixed on stationary knife (27), the stationary knife (27) is located at the left end of lower axle (1)；The trimming moving knife component (11) includes cutting Line crank (28), trimming connecting rod (29), moving knife (30) and movable knife rack (37), one end of the trimming crank (28) and the trimming The left end of axis (2) is fixedly connected with, the both ends of the trimming connecting rod (29) respectively with the other end of the trimming crank (28) and dynamic Knife rest (37) is hinged, and the moving knife (30) is fixed on movable knife rack (37).

7. the automatic shearing mechanism of sewing machine according to claim 6, which is characterized in that solid on the bottom plate (3) of sewing machine Surely have fixing sleeve (31), the shear spool (2) passes through the fixing sleeve (31), is arranged with reduction torsion spring on the fixing sleeve (31) (32), the effect end of the reduction torsion spring (32) connect with the trimming crank (28) or against.

8. the automatic shearing mechanism of sewing machine according to claim 7, which is characterized in that the right end of the fixing sleeve (31) It is fixed with retaining ring (33), is provided with reseting pressuring spring (34) between the retaining ring (33) and trimming driving crank (9), the reset pressure Spring (34) is sheathed on shear spool (2)；When the reseting pressuring spring (34) is in reset state, the trimming drives crank (9) Positioned at the right side of the trimming cam (4).

9. a kind of sewing machine, which is characterized in that the sewing machine includes the automatic shearing as described in claim 1-8 any one Mechanism.