CN217459832U - Thread cutting and moving device for sewing machine - Google Patents

Abstract

The utility model provides a trimming moves sword cord grip of sewing machine belongs to sewing machine accessory technical field. It has solved the problem of easy jump needle when sewing machine rises the needle among the prior art. The sewing machine comprises a base and a lower shaft, wherein a trimming moving knife and a rotating shuttle are arranged on the lower shaft, the rotating shuttle is provided with a shuttle tip part used for hooking upper facial suture of a needle, the trimming moving knife line pressing device comprises a line pressing part arranged on the base, the trimming moving knife can upwards rotate to the upper part of the rotating shuttle and can rotate to the position abutted against the line pressing part, a line accommodating groove is formed in the trimming moving knife, a hooking part is formed at the notch of the line accommodating groove, the facial suture on the needle can be hooked into the line accommodating groove by the line hooking part in the rotating process, and the line pressing part can press the upper facial suture in the line accommodating groove against the trimming moving knife after the trimming moving knife rotates in place. The utility model has the advantages of that the needle jumping phenomenon of the needle raising stage of the sewing machine can be avoided to generate a larger bird nest.

Description

Thread cutting and moving device for sewing machine

Technical Field

The utility model belongs to the technical field of sewing machine accessories, a trimming moves sword cord grip of sewing machine is related to.

Background

A sewing machine is a machine that uses one or more sewing threads to form one or more stitches in a material to be sewn, thereby interweaving or stitching one or more layers of material. When the sewing machine works, a needle leading belt upper thread penetrates through a sewing material and is lifted upwards after reaching a lower limit position, because friction force exists between the sewing material and a sewing thread, the upper thread cannot be lifted synchronously along with a needle but is retained below the sewing material and is expanded to two sides of the needle under the action of elasticity to form a ring shape, then a shuttle tip of a rotating shuttle hooks into a thread ring and continues to rotate, the thread ring is simultaneously expanded, and a guide thread ring encircles a shuttle core to form a lock stitch, when the needle is pulled up (next first needle), the upper thread is kept in the upper thread by the friction force between the upper thread and the sewing material, at the moment, the opposite side of the friction force of the upper thread side is smaller than the friction force of an upper thread tail (needle passing part), in order to prevent the upper thread from generating a larger bird nest in the sewing process, the sewing quality and the sewing efficiency are influenced, the length between the upper thread end and a needle hole is controlled, the length between the upper thread end and the needle hole is short, the rotating shuttle forms a thread loop after thread hooking and expands the thread loop, the upper thread end is pulled downwards away from the fabric in the process of thread loop expanding, the upper thread cannot form an effective locking stitch with the bottom thread, the needle skipping phenomenon is caused, the result that the material cannot be sewn in the lifting sewing is caused, and the sewing quality and the sewing efficiency are still greatly reduced due to the needle skipping phenomenon.

Disclosure of Invention

The utility model aims at solving the problems in the prior art, and provides a thread cutting and pressing device for a sewing machine. The technical problem solved by the utility model is how to avoid producing a big bird's nest and solve the needle skipping phenomenon in the needle raising stage of the sewing machine.

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

the utility model provides a sewing machine's trimming moves sword cord grip, sewing machine includes base and lower shaft, is provided with trimming on the lower shaft and moves sword and rotating shuttle, and the rotating shuttle has the shuttle point portion that is used for catching a hook and gets upper thread of eedle, its characterized in that, this trimming moves sword cord grip and includes the line ball spare of setting on the base, trimming moves the sword and can upwards rotate to the top of rotating shuttle and can revolve to the position with line ball spare looks butt, and trimming moves and is provided with the line containing groove on the sword, and is formed with the crochet hook line portion in the notch department of line containing groove, and the crochet hook portion can hook the upper thread on the eedle into line containing groove in the in-process of gyration, the line ball spare can press the upper thread that is located the line containing groove on trimming moves the sword after trimming moves the sword gyration and targets in place.

When a sewing machine lifts a needle (a next first needle), the needle is driven by a needle bar mechanism of the sewing machine to lead the upper thread to pass through sewing materials and form an upper thread loop, a shuttle sharp part of a rotating shuttle hooks the loop and then continuously rotates forwards, an upper thread head is driven by the shuttle sharp part to move downwards and be pulled away from the fabric, the needle moves upwards and leaves the bottom surface of a needle plate, then a trimming movable blade rotates upwards to the upper part of the rotating shuttle, a hooking part on the trimming movable blade is positioned at one side of the upper thread and faces the upper thread, therefore, in the process of rotating the trimming movable blade, the hooking part can smoothly hook the upper thread on the needle and drive the upper thread to rotate together, then the trimming movable blade rotates to the position abutting against a thread pressing part, the upper thread can move inwards along the thread hooking part and enter a thread accommodating groove in the rotating process, and meanwhile, in the process of rotating the trimming movable blade until the trimming movable blade rotates to the right position, the thread pressing part and the movable blade continuously approach to the thread pressing part, at the moment, the upper thread positioned in the thread accommodating groove is positioned below the thread pressing piece, the thread pressing piece and the upper thread are also kept close to each other in the rotation process, when the thread cutting movable knife rotates to the right position, the thread pressing piece is abutted against the thread cutting movable knife, and simultaneously the upper thread positioned below the thread pressing piece is also abutted against the thread cutting movable knife together, because the needle is positioned above the bottom surface of the needle plate at the moment, the thread head of the upper thread moves downwards under the driving of the sharp part of the shuttle and is pulled away from the fabric, the upper thread cannot be interwoven with the bottom thread when the first needle is positioned below the needle, then the needle continues to move downwards under the driving of the needle rod mechanism of the sewing machine to lead the upper thread to pass through the sewing material and form an upper thread loop (namely, a lower second needle, the sewing material is required to be noticed to move forwards before the lower second needle, and the lower second needle is not positioned at the same position as the lower first needle of the sewing material), at the moment, the thread head is positioned below the sewing material, the needle is arranged above the sewing material, after a second needle is arranged below the needle, a part of facial suture is retained above the sewing material, so that the facial suture forms facial suture loops above and below the sewing material, meanwhile, the side of the head of the facial suture is arranged in the thread accommodating groove and is pressed on the thread cutting movable knife by the thread pressing piece, the side of the tail part of the facial suture (the needle passing part) is arranged on the needle, the length of the facial suture loop below the sewing material on the needle is kept appropriate, meanwhile, the stability of the facial suture loop is better, the facial suture loop can be ensured to be hooked by the sharp part of the shuttle in the forward rotating process, an effective stitch form can be ensured by the facial suture loop and the bottom thread, finally, the interweaving of the facial suture loop and the bottom thread is completed by rotating, the needle skipping phenomenon of the needle raising stage of the sewing machine is avoided while a large bird nest is generated, wherein the sewing material can gradually drag the facial suture in the thread accommodating groove away from the thread accommodating groove in the moving process, meanwhile, the upper thread is gradually separated from the pressing of the thread pressing piece.

In the thread cutting moving blade thread pressing device of the sewing machine, the thread pressing piece can generate elastic deformation, and the thread hooking part is positioned at the outer side of the shuttle tip part and at the inner side of the machine needle. The thread pressing piece can generate elastic deformation, on one hand, the thread cutting movable knife can be prevented from generating hard contact with the thread cutting movable knife when the thread cutting movable knife rotates to a position abutting against the thread pressing piece, and on the other hand, the thread can not be damaged in the process that the sewing material pulls the thread from the thread accommodating groove; the thread hooking part is positioned on the outer side of the shuttle sharp part and on the inner side of the needle, so that the thread hooking part can smoothly hook the upper thread on the needle in the rotating process of the thread cutting movable knife.

In the trimming moving knife thread pressing device of the sewing machine, the trimming moving knife is further provided with a wire notch capable of accommodating a needle, the thread accommodating groove is formed by inwards and upwards extending from the side wall of the wire notch, and the surface of the side wall of the thread accommodating groove facing the thread hooking part is arc-shaped. When the movable trimming cutter starts to rotate, the upper thread on the needle is positioned in the conductor notch, so that the conductor notch can limit the upper thread in the conductor notch in the process that the movable trimming cutter starts to rotate until the movable trimming cutter rotates in place, and the hook part can smoothly hook the upper thread on the needle in the rotating process of the movable trimming cutter; the lateral wall surface that holds the wire casing and keep away from the crochet hook portion is the arc, can further avoid sewing the material and drag the in-process damage facial suture that holds the wire casing with the facial suture.

In the thread trimming moving blade thread presser of the sewing machine, both side walls of the thread hooking part are linear. The structure enables the thread hooking part to be in a pointed end shape, so that the thread hooking part can smoothly hook the upper thread on the needle in the rotating process of the thread cutting movable knife, and the upper thread can move inwards along the thread hooking part to enter the thread containing groove in the rotating process.

In the trimming movable knife thread pressing device for the sewing machine, the thread pressing piece is arranged on the base through the thread pressing support, the thread pressing piece comprises a thread pressing part capable of being pressed against the trimming movable knife and an installation part used for being connected with the thread pressing support, and the thread pressing part is plate-shaped and made of metal. The structure is convenient for the disassembly and the replacement of the wire pressing piece, and simultaneously, the fixed strength of the wire pressing piece can be ensured by the installation part of the wire pressing piece, the wire pressing part of the wire pressing piece is made of metal and has certain deformation capacity, on one hand, the hard contact between the wire shearing moving knife and the wire shearing moving knife when the wire shearing moving knife rotates to the position in butt joint with the wire pressing piece can be avoided, on the other hand, the upper wire cannot be damaged in the process that the upper wire is dragged away from the wire accommodating groove by sewing materials, in addition, when the elastic deformation occurs to the wire pressing part, the wire pressing part always has the trend of moving the wire shearing moving knife, and the wire pressing part is plate-shaped, the butt area of the wire pressing part and the wire shearing moving knife is larger, and the wire pressing effect of the wire pressing part capable of generating the elastic deformation is better.

In foretell a trimming moves sword crimping device for sewing machine, be provided with the mounting groove on the base, the line ball support is the step form, and the one end setting of line ball support is provided with the step face in the mounting groove on its other end, the installation department is platelike and can dismantle the setting on the step face. The structure enables the wire pressing support and the base as well as the wire pressing piece and the wire pressing support to be fixed more firmly, and meanwhile, the wire pressing piece and the wire pressing support are convenient to disassemble and assemble.

In the thread cutting moving blade thread pressing device for the sewing machine, the width of the thread guiding notch is gradually reduced from the opening to the bottom. The thread cutting movable knife is made to rotate until the thread cutting movable knife rotates in place, the thread guide notch can limit the upper thread in the thread guide notch, the width of the thread guide notch is gradually reduced from the opening to the bottom, and when the thread cutting movable knife rotates, the upper thread is located in the narrow position of the thread guide notch, so that the thread guide notch can better reduce the shaking and shaking range of the upper thread, and the thread hooking part can smoothly hook the upper thread on the needle in the rotating process of the thread cutting movable knife.

In the thread trimming moving blade thread pressing device for the sewing machine, the bottom wall and the two side walls of the thread accommodating groove are in transitional connection through the first arc-shaped sections respectively. The structure can further prevent the upper thread from being damaged in the process of entering or separating from the thread containing groove.

In foretell a thread trimming moves sword thread presser for sewing machine, the both sides wall of wire breach all is the inclined plane setting that leans out, respectively through second segmental arc transitional coupling between the diapire of wire breach and the both sides wall. The structure can further prevent the upper thread from being damaged in the notch of the lead.

In the trimming moving blade thread pressing device for the sewing machine, the lower shaft is provided with the moving blade seat fixedly connected with the base, the moving blade seat is rotatably provided with the moving blade holder, the base is provided with the motor, the rotating shaft of the motor is provided with the trimming crank, the trimming crank is connected with the moving blade holder through the bent connecting rod, and the trimming moving blade is arranged on the moving blade holder. The structure can better realize the upward rotation and the rotation of the trimming movable knife, particularly, the motor drives the trimming crank arranged on the rotating shaft of the motor to rotate firstly, then the trimming crank drives the movable knife rest to rotate through the bent connecting rod, the trimming movable knife arranged on the movable knife rest rotates along with the trimming crank, and then the upward rotation or the downward rotation of the trimming movable knife is realized through the forward and reverse rotation of the motor.

Compared with the prior art, this a trimming moves sword cord grip for sewing machine's advantage lies in: this a trimming moves sword cord grip for sewing machine can ensure that upper thread and bottom line form effective locking-type stitch seam at the sewing machine needle jack stage to solve the jump needle phenomenon in sewing machine needle jack stage when avoiding producing great bird's nest, and then can improve sewing quality and sewing efficiency, simultaneously, this a trimming moves sword of trimming moves sword cord grip for sewing machine's trimming and still can accomplish the trimming action with the cooperation of trimming stationary knife, is favorable to popularizing and applying.

Drawings

FIG. 1 is a schematic structural view of the thread trimming and moving blade pressing device for a sewing machine, which is arranged on a sewing machine base (without a base cover plate).

Fig. 2 is a partially enlarged view of a portion a in fig. 1.

FIG. 3 is a schematic view of the thread trimming and moving blade pressing device for a sewing machine, which is arranged on a sewing machine base (including a base cover plate).

Fig. 4 is a partially enlarged view at B in fig. 3.

FIG. 5 is a schematic top view of a part of the thread trimming and moving blade pressing device for a sewing machine, which is disposed on a base (including a base cover plate) of the sewing machine.

Fig. 6 is a partially enlarged view at D in fig. 5.

FIG. 7 is a second schematic structural view of the thread trimming and moving blade pressing device for a sewing machine, which is arranged on a sewing machine base (including a base cover plate).

Fig. 8 is a partial enlarged view at C in fig. 7.

FIG. 9 is a schematic view of the three-dimensional structure of the trimming moving blade thread-pressing device for sewing machine.

FIG. 10 is a schematic perspective view of the thread pressing piece and the thread pressing bracket of the trimming knife thread pressing device for sewing machine.

Fig. 1, 2, 3, 4, 5 and 6 are schematic structural views of the movable trimming blade when the movable trimming blade rotates to a position abutting against the thread pressing member, and fig. 7 and 8 are schematic structural views of the movable trimming blade when the movable trimming blade rotates upward to a position above the rotating shuttle.

In the figure, 1, a base; 2. a needle; 3. a lower shaft; 4. trimming and moving the knife; 5. rotating the shuttle; 6. a shuttle tip; 7. a wire pressing member; 71. an installation part; 72. a wire pressing part; 8. a wire gap; 9. a wire accommodating groove; 10. a hook line portion; 11. a wire pressing bracket; 12. mounting grooves; 13. a step surface; 14. a first arcuate segment; 15. a second arcuate segment; 16. a movable cutter seat; 17. a movable knife rest; 18. a thread cutting crank; 19. a bent connecting rod; 20. an electric motor.

Detailed Description

The following are specific embodiments of the present invention and the accompanying drawings are used to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

A trimming moving knife thread pressing device of a sewing machine is disclosed, referring to fig. 1-10, the sewing machine comprises a base 1 and a lower shaft 3, a trimming moving knife 4 and a rotating shuttle 5 are arranged on the lower shaft 3, the rotating shuttle 5 is provided with a shuttle tip part 6 used for hooking upper threads of a needle 2, the trimming moving knife thread pressing device comprises a thread pressing part 7 arranged on the base 1, the trimming moving knife 4 can upwards rotate to the upper part of the rotating shuttle 5 and can rotate to a position abutting against the thread pressing part 7, a thread accommodating groove 9 is arranged on the trimming moving knife 4, a hook thread part 10 is formed at the notch of the thread accommodating groove 9, the hook thread part 10 can hook the upper threads of the needle 2 into the thread accommodating groove 9 in the rotating process, and the thread pressing part 7 can press the upper threads in the thread accommodating groove 9 against the trimming moving knife 4 after the trimming moving knife 4 rotates in place. Specifically, the lower shaft 3 is provided with a movable knife holder 16 fixedly connected with the base 1, the movable knife holder 16 is rotatably provided with a movable knife rest 17, the base 1 is provided with a motor 20, a rotating shaft of the motor 20 is provided with a wire cutting crank 18, the wire cutting crank 18 is connected with the movable knife rest 17 through a bent connecting rod 19, and the wire cutting movable knife 4 is arranged on the movable knife rest 17.

Referring to fig. 1 to 8, further, the thread pressing member 7 is elastically deformable, and the thread hooking portion 10 is located outside the shuttle tip 6 and inside the needle 2. The thread pressing piece 7 can generate elastic deformation, so that hard contact with the thread shearing movable knife 4 can be avoided when the thread shearing movable knife 4 rotates to a position abutting against the thread pressing piece 7, and the thread can not be damaged when the sewing material drags the thread from the thread accommodating groove 9; the thread hooking part 10 is positioned on the outer side of the shuttle sharp part 6 and on the inner side of the needle 2, so that the thread hooking part 10 can smoothly hook the upper thread on the needle 2 in the rotating process of the thread trimming moving blade 4.

Referring to fig. 1 to 9, further, a wire notch 8 capable of accommodating the needle 2 is further arranged on the trimming moving blade 4, the wire accommodating groove 9 is formed by extending inward and upward from a side wall of the wire notch 8, and a side wall surface of the wire accommodating groove 9 facing the hook portion 10 is arc-shaped. The side wall surface of the line containing groove 9 far away from the line hooking part 10 is arc-shaped, so that the damage to the facial line in the process of dragging the facial line away from the line containing groove 9 by sewing materials can be further avoided. Both side walls of the hooking part 10 are linear. The structure enables the thread hooking part 10 to be in a pointed shape, so that the thread hooking part 10 can smoothly hook the upper thread on the needle 2 in the rotating process of the thread cutting movable blade 4, and the upper thread can conveniently move inwards along the thread hooking part 10 to enter the thread accommodating groove 9 in the rotating process. The width of the wire gap 8 is gradually reduced from the opening to the bottom. The thread cutting movable knife 4 starts to rotate until the thread cutting movable knife rotates in place, the thread guide notch 8 can limit the upper thread in the thread guide notch 8, and when the thread cutting movable knife 4 starts to rotate, the upper thread is located in a narrow position of the thread guide notch 8, so that the swinging and swinging amplitude of the upper thread can be reduced better, the thread cutting movable knife 4 can be further ensured to hook the upper thread on the needle 2 smoothly in the rotating process, and the thread hooking part 10 can be further ensured to hook the upper thread on the needle 2.

Referring to fig. 1-8 and 10, further, the wire pressing member 7 is disposed on the base 1 through the wire pressing bracket 11, the wire pressing member 7 includes a wire pressing portion 72 capable of pressing against the movable trimming blade 4 and a mounting portion 71 for connecting with the wire pressing bracket 11, and the wire pressing portion 72 is plate-shaped and made of metal. Be provided with mounting groove 12 on the base 1, line ball support 11 is the step form, and the one end setting of line ball support 11 is provided with step face 13 in mounting groove 12, its other end on the line ball support 11, installation department 71 is platelike and can dismantle the setting on step face 13. The structure enables the line pressing support 11 and the base 1 and the line pressing piece 7 and the line pressing support 11 to be fixed more firmly, and the line pressing piece 7 and the line pressing support 11 are convenient to disassemble, assemble and replace. Meanwhile, the installation part 71 of the wire pressing part 7 can ensure the fixed strength of the wire pressing part 7, the wire pressing part 72 of the wire pressing part 7 is made of metal and has certain deformation capacity, on one hand, hard contact with the trimming moving blade 4 can be avoided when the trimming moving blade 4 rotates to a position abutting against the wire pressing part 7, on the other hand, the upper thread cannot be damaged in the process of dragging the upper thread from the thread accommodating groove 9 by sewing materials, in addition, when the wire pressing part 72 elastically deforms, the wire pressing part 72 always has a tendency of moving towards the trimming moving blade 4, and the wire pressing part 72 is plate-shaped, so that the abutting area of the wire pressing part 72 and the trimming moving blade 4 is larger, and the wire pressing effect of the wire pressing part 72 capable of elastically deforming is better.

Referring to fig. 9, further, the bottom wall and the two side walls of the wire accommodating groove 9 are respectively in transition connection through a first arc-shaped section 14. The structure can further avoid the loss of the upper thread in the process of entering or separating from the thread containing groove 9. Both sides wall of wire breach 8 all is the inclined plane setting that leans out, respectively through 15 transitional coupling of second arc section between the diapire of wire breach 8 and the both sides wall. The above structure can further prevent the upper thread from being damaged in the conductor notch 8.

This a thread trimming moves knife cord grip for sewing machine's theory of operation: when a sewing machine lifts a needle (a next first needle), the needle 2 is driven by a needle bar mechanism of the sewing machine to lead the upper thread to pass through the sewing material and form an upper thread loop, the shuttle tip part 6 of the rotating shuttle 5 hooks the loop and then continuously rotates forwards, the upper thread end is driven by the shuttle tip part 6 to move downwards and be pulled away from the sewing material, at the moment, the needle 2 moves upwards and leaves the bottom surface of a needle plate, then the movable trimming cutter 4 rotates upwards to the upper part of the rotating shuttle 5, at the moment, the hooking part 10 on the movable trimming cutter 4 is positioned at one side of the upper thread and faces the upper thread, therefore, in the rotation process of the movable trimming cutter 4, the hooking part 10 can smoothly hook the upper thread on the needle 2 and drive the upper thread to rotate together, then the movable trimming cutter 4 rotates to the position abutting against the thread pressing piece 7, in the rotation process, the upper thread can move inwards along the hooking part 10 to enter the thread accommodating groove 9, and simultaneously, in the rotation process of the movable trimming cutter 4 starts to rotate until the upper trimming cutter is in place, the thread pressing piece 7 and the thread cutting movable knife 4 are continuously close to each other, the upper thread in the thread accommodating groove 9 is positioned below the thread pressing piece 7, the thread pressing piece 7 and the upper thread are also continuously close to each other in the rotation process, when the thread cutting movable knife 4 rotates to the right position, the thread pressing piece 7 is abutted against the thread cutting movable knife 4, and simultaneously the upper thread positioned below the thread pressing piece 7 is pressed against the thread cutting movable knife 4 together, because the needle 2 is positioned above the bottom surface of the needle plate at the moment, the upper thread end moves downwards under the driving of the shuttle tip part 6 and is pulled away from the fabric, the upper thread cannot be interwoven with the bottom thread when the first needle is positioned below the needle 2, then the needle 2 continues to move downwards under the driving of a needle rod mechanism of the sewing machine to lead the upper thread to pass through the sewing material and form an upper thread loop (namely, a lower second needle, and it needs to be noted that the sewing material before the lower second needle 2 moves forwards), and because the upper thread end is positioned below the sewing material, the machine needle 2 is located above the sewing material, behind the second needle under the machine needle 2, a part of upper thread can be detained in the top of sewing material, so the upper thread can all form the loop in the top and below of sewing material, and simultaneously, the side of upper thread end of a thread is located thread-accommodating groove 9 and is pressed and supported on cutting knife 4 by thread-pressing piece 7, the side of upper thread tail (crossing machine needle 2 part) is located the machine needle 2, make the length of the upper thread loop that is located below the sewing material on the machine needle 2 keep suitable, make the stability of this upper thread loop better simultaneously, can not only ensure that shuttle point portion 6 can hook the face thread loop in the process of forward rotation, and can ensure that shuttle thread loop and bottom thread form effective locking-type stitch, last finish the interweaving of upper thread loop and bottom thread by spiral 5, thereby solve the jump needle phenomenon in the sewing machine needle raising stage when avoiding producing great bird's nest. Wherein, the seam material can drag away from the facial line of holding in the line groove 9 gradually at the in-process that removes hold line groove 9, simultaneously, also make the facial line break away from the pressure of wire pressing piece 7 gradually and support, because wire pressing piece 7 can take place elastic deformation, so can not take place the damage at above-mentioned in-process facial line ring. Wherein, the rotation principle of the thread cutting movable knife 4 is as follows: the motor 20 firstly drives the trimming crank 18 arranged on the rotating shaft of the motor 20 to rotate, then the trimming crank 18 drives the movable knife rest 17 to rotate through the bent connecting rod 19, the trimming movable knife 4 arranged on the movable knife rest 17 rotates along with the trimming crank, and then the trimming movable knife 4 rotates upwards or downwards through the forward and reverse rotation of the motor 20.

It should be noted that: the trimming movable knife 4 of the trimming movable knife thread-pressing device for the sewing machine can still be matched with the trimming fixed knife to finish the trimming action.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Claims (10)

1. A thread trimming, moving and pressing device of a sewing machine comprises a base (1) and a lower shaft (3), wherein the lower shaft (3) is provided with a thread trimming, moving blade (4) and a rotating shuttle (5), the rotating shuttle (5) is provided with a shuttle tip part (6) for hooking upper threads of a needle (2), it is characterized in that the trimming moving knife line pressing device comprises a line pressing piece (7) arranged on a base (1), the trimming moving knife (4) can rotate upwards to the upper part of the rotating shuttle (5) and can rotate to the position abutting against the thread pressing piece (7), a thread containing groove (9) is arranged on the trimming moving knife (4), a hook part (10) is formed at the notch of the line accommodating groove (9), and the hook part (10) can hook the surface line on the needle (2) into the line accommodating groove (9) in the rotation process, the thread pressing piece (7) can press the facial line in the thread accommodating groove (9) against the movable trimming cutter (4) after the movable trimming cutter (4) rotates in place.

2. The trimming and moving blade thread-pressing device of sewing machine according to claim 1, wherein the thread-pressing member (7) is elastically deformable, and the thread hooking portion (10) is located outside the shuttle tip portion (6) and inside the needle (2).

3. The trimming moving blade thread pressing device of the sewing machine according to claim 1, wherein the trimming moving blade (4) is further provided with a thread guiding notch (8) capable of accommodating a needle (2), the thread accommodating groove (9) is formed by extending inwards and upwards from the side wall of the thread guiding notch (8), and the surface of the side wall of the thread accommodating groove (9) facing the thread hooking part (10) is arc-shaped.

4. The trimming and moving blade line pressing device of a sewing machine according to claim 3, wherein both side walls of the hook line part (10) are linear.

5. The trimming moving blade thread-pressing device of the sewing machine according to any one of claims 1 to 4, characterized in that the thread-pressing member (7) is arranged on the base (1) through a thread-pressing bracket (11), the thread-pressing member (7) comprises a thread-pressing part (72) which can be pressed against the trimming moving blade (4) and a mounting part (71) which is used for being connected with the thread-pressing bracket (11), and the thread-pressing part (72) is plate-shaped and made of metal.

6. The trimming and moving blade line pressing device of the sewing machine according to claim 5, wherein the base (1) is provided with a mounting groove (12), the line pressing bracket (11) is step-shaped, one end of the line pressing bracket (11) is arranged in the mounting groove (12), the other end of the line pressing bracket is provided with a step surface (13), and the mounting part (71) is plate-shaped and is detachably arranged on the step surface (13).

7. The trimming moving-blade thread pressing device of a sewing machine according to claim 3 or 4, wherein the width of the thread guiding notch (8) is gradually reduced from the opening to the bottom.

8. The trimming and moving blade line pressing device of the sewing machine according to any one of claims 1 to 4, characterized in that the bottom wall and the two side walls of the line accommodating groove (9) are respectively in transitional connection through a first arc-shaped section (14).

9. The thread trimming and moving blade line pressing device of the sewing machine according to claim 3 or 4, wherein both side walls of the thread guiding notch (8) are arranged in an outward inclined plane, and the bottom wall and both side walls of the thread guiding notch (8) are respectively in transitional connection through the second arc-shaped section (15).

10. The trimming and moving blade line pressing device of the sewing machine according to any one of claims 1 to 4, wherein the lower shaft (3) is provided with a moving blade holder (16) fixedly connected with the base (1), the moving blade holder (16) is rotatably provided with a moving blade holder (17), the base (1) is provided with a motor (20), a rotating shaft of the motor (20) is provided with a trimming crank (18), the trimming crank (18) is connected with the moving blade holder (17) through a bent connecting rod (19), and the trimming moving blade (4) is arranged on the moving blade holder (17).

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