Thread trimming mechanism of sewing machine

Abstract

The utility model provides a thread trimming mechanism of a sewing machine, and belongs to the technical field of sewing equipment. The thread trimming mechanism solves the problem that a thread of an existing thread trimming mechanism of the sewing machine is prone to falling off after trimming. According to the thread trimming mechanism of the sewing machine, the sewing machine comprises a machine shell and a knife rest fixed to the machine shell, the thread trimming mechanism comprises a fixed knife, a movable knife and an elastic pressing piece, the fixed knife and the movable knife are arranged on the knife rest, the elastic pressing piece is located on one side of the fixed knife and provided with a thread pressing end, and the thread pressing end of the elastic pressing piece can press a cut thread on the side face of the fixed knife. The thread trimming mechanism further comprises a long-strip-shaped auxiliary elastic piece, one end of the auxiliary elastic piece is fixed to the tool rest, the other end of the auxiliary elastic piece is pressed against the side face, opposite to the fixed tool, of the thread pressing end of the elastic pressing piece, and an adjusting piece capable of adjusting the pressing force of the auxiliary elastic piece on the elastic pressing piece is further arranged on the tool rest. The thread trimming mechanism of the sewing machine can avoid the phenomenon that a thread falls off after thread trimming.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewing equipment and relates to a thread trimming mechanism of a sewing machine. Background Art

[0002] A sewing machine is a machine that uses one or more sewing threads to form one or more stitches on the sewing material, so that one or more layers of sewing materials are interwoven or sewn together, including flat sewing machines, chain sewing machines, quilting machines, overlock sewing machines, and upper sewing machines. Sewing machines can sew fabrics such as cotton, linen, silk, wool, and synthetic fibers, as well as products such as leather, plastic, and paper. The stitches are neat, beautiful, flat, and firm, and the sewing speed is fast and easy to use. At the end of sewing, the sewing machine needs to cut the sewing thread, so a thread cutting mechanism is provided on the sewing machine, including a fixed knife and a moving knife. The fixed knife is fixedly set, and a hooking groove is provided on the moving knife. When the thread needs to be cut, the moving knife extends and hooks the sewing thread, and then cooperates with the fixed knife to cut the sewing thread when it is retracted. At the same time, in order to prevent the cut bottom thread from falling off, the thread cutting mechanism will also be provided with a pressing plate to press the cut thread head.

[0003] As disclosed in the patent application (application number: 201620712693.1), the lasting machine with a wire cutting device is composed of a main body, a feeding device, a driving device and a wire cutting device. The wire cutting device is mainly composed of a fixed seat, a cutting component, a driving source, a wire hooking component and a spring sheet. The driving source is a pneumatic cylinder and a telescopic rod. The pneumatic cylinder can drive the telescopic rod to perform reciprocating linear motion. The spring sheet has a connecting end and a contact end. The connecting end of the spring sheet is connected to the fixed plate, and the contact end of the spring sheet can contact the cutting component. When the sewing operation is completed and the thread cutting is ready, the pneumatic cylinder drives the telescopic rod to extend outward in a straight line, so that the telescopic rod drives the thread hooking assembly to move in a straight line, so that the thread hooking assembly passes through the operating space and hooks the suture, and the thread hooking assembly pulls the suture to the cutting position of the cutting assembly. The contact end of the spring sheet applies pressure to the thread hooking assembly, so that the contact end of the spring sheet pushes the suture to the blade of the cutting assembly, and then the blade of the cutting assembly cuts the suture, and at the same time, the bottom thread head remaining on the thread hooking assembly can be pressed by the spring sheet.

[0004] Since the above-mentioned spring piece is a metal sheet, it generates elastic force through its own deformation, and uses this elastic force to press the suture. However, during long-term use, the spring piece frequently rubs against the moving knife, causing the spring piece to wear. At the same time, the spring piece will also age or harden, causing the pressing force of the spring piece on the suture to decrease, and the suture will fall off after being cut. Summary of the invention

[0005] The utility model aims to solve the above problems in the prior art and proposes a thread trimming mechanism for a sewing machine, so as to solve the problem that the thread trimming mechanism of the prior sewing machine is prone to thread falling off after thread trimming.

[0006] The purpose of the utility model can be achieved through the following technical solutions: a thread cutting mechanism of a sewing machine, the sewing machine includes a casing and a knife rack fixed on the casing, the thread cutting mechanism includes a fixed knife, a movable knife and an elastic pressing piece located on one side of the fixed knife and having a thread pressing end, and the thread pressing end of the elastic pressing piece can press the cut suture against the side of the fixed knife, characterized in that the thread cutting mechanism also includes a long strip of auxiliary spring sheet, one end of the auxiliary spring sheet is fixed on the knife rack, and the other end is pressed against the side of the thread pressing end of the elastic pressing piece facing away from the fixed knife, and the knife rack is also provided with an adjusting member that can adjust the pressing force of the auxiliary spring sheet on the elastic pressing sheet.

[0007] The knife holder, fixed knife and movable knife are all facing the sewing position of the machine needle. When the thread needs to be cut, the movable knife extends out under the action of the driving member, which can be a power source such as a cylinder or an electromagnet. The movable knife can hook the suture and then retract. During the retraction process, the movable knife cooperates with the fixed knife to cut the suture. The cut suture can be pressed on the side of the fixed knife by the pressing end of the elastic pressing plate with elasticity. The sewing machine is also provided with an auxiliary spring sheet, which is pressed against the outer surface of the pressing end of the elastic pressing plate under its own elastic force, that is, the suture is pressed by the joint force of the elastic pressing plate and the auxiliary spring sheet, and the stability and reliability are higher. Furthermore, when the elastic pressing plate is used for a period of time and becomes aged or the elastic force becomes weak, the adjusting member can adjust and increase the pressing force of the auxiliary spring sheet on the elastic pressing plate, thereby compensating for the elastic force of the elastic pressing plate that is reduced due to aging, ensuring that the suture is always pressed by sufficient force, and avoiding the phenomenon of suture falling off after cutting the thread.

[0008] In the thread trimming mechanism of the sewing machine, the elastic pressing piece is in the shape of a long strip, and one end of the elastic pressing piece is a fixed part fixed on the knife holder, and the other end of the elastic pressing piece is the above-mentioned thread pressing end. The elastic pressing piece is in the shape of a long strip, generates elastic force through its own deformation, and the fixed part at one end is fixed on the knife holder, and the other end extends to the side of the fixed knife and presses against the side of the fixed knife.

[0009] In the thread trimming mechanism of the sewing machine, the thread pressing end includes an elastic part connected to the fixed part at one end and a thread pressing part connected to the other end of the elastic part, and the auxiliary spring piece is pressed against the side of the elastic part facing away from the fixed knife or the side of the thread pressing part facing away from the fixed knife. The thread pressing end is not limited to the thread pressing position, and the auxiliary spring piece can be pressed against the outer surface of the thread pressing part or against the elastic part away from the thread pressing part, which can also provide additional force for the thread pressing part to ensure the reliability of thread pressing.

[0010] In the thread trimming mechanism of the sewing machine, the elastic pressing sheet and the auxiliary spring sheet are both metal sheets with approximately the same width, and the thickness of the auxiliary spring sheet is greater than that of the elastic pressing sheet. That is, the elastic force of the auxiliary spring sheet is greater than that of the elastic pressing sheet, so that when the elastic force of the elastic pressing sheet decays, the auxiliary spring sheet still has sufficient auxiliary force, thereby ensuring that the thread pressing portion of the elastic pressing sheet can reliably press the sewing thread.

[0011] In the thread trimming mechanism of the sewing machine, the auxiliary spring sheet is located on the side of the elastic pressing sheet facing away from the fixed knife, and one end of the auxiliary spring sheet is fitted and fixed on the fixed part, and the other end is bent toward the side where the fixed knife is located and pressed against the thread pressing end of the elastic pressing sheet. The auxiliary spring sheet exerts a force on the elastic pressing sheet toward the fixed knife, and the structure is simple and compact.

[0012] In the thread trimming mechanism of the sewing machine, the adjusting member includes a bolt and an adjusting knob, a clearance hole is provided on the auxiliary spring sheet, a through hole is provided on the elastic pressing sheet, the bolt passes through the clearance hole and the through hole and is fixed on the tool holder, the adjusting knob is screwed on the bolt, and the adjusting knob is located between the elastic pressing sheet and the auxiliary spring sheet. The adjusting knob abuts against and supports the auxiliary spring sheet, so that the auxiliary spring sheet applies a partial force to the elastic pressing sheet. When the elastic force of the elastic pressing sheet decays, the adjusting knob is rotated to make the adjusting knob slightly adjusted toward the side where the fixed knife is located, thereby slightly releasing the auxiliary spring sheet and increasing the force of the auxiliary spring sheet on the elastic pressing sheet; as another structure of the adjusting member, the adjusting member can also use a screw, a screw hole is provided on the tool holder, one end of the screw is screwed into the screw hole of the tool holder, and the other end passes through the through hole of the elastic pressing sheet and abuts against the auxiliary spring sheet. By rotating the screw, the force of the auxiliary spring sheet on the elastic pressing sheet can be adjusted.

[0013] In the thread trimming mechanism of the sewing machine, the auxiliary spring sheet includes a connecting portion fixedly connected to the knife holder and an adjusting portion connected to the connecting portion and arched toward the side away from the fixed knife. The above-mentioned clearance hole is provided on the adjusting portion. There is an installation spacing between the adjusting portion and the fixing portion of the elastic pressing piece. The adjusting knob is located within the installation spacing. The adjusting portion is located between the adjusting knob and the head of the bolt. The adjusting portion abuts against the adjusting knob. Rotating the adjusting knob can push the adjusting portion, thereby adjusting the force acting on the elastic pressing piece.

[0014] In the thread trimming mechanism of the sewing machine, the auxiliary spring sheet further comprises an inclined portion connected to the adjusting portion and a pressing portion connected to the inclined portion, a gap is provided between the inclined portion and the elastic portion of the elastic pressing sheet, and the pressing portion is pressed against the thread pressing portion of the elastic pressing sheet. By the inclined portion inclined toward one side of the fixed knife, the pressing portion is extended to the side of the fixed knife and pressed against the thread pressing portion, that is, the pressing portion directly acts on the thread pressing position, thereby improving the thread pressing reliability.

[0015] In the thread trimming mechanism of the sewing machine described above, the knife holder is in the shape of an elongated strip, and a guide groove is provided on one side of the knife holder along the length direction, the fixed knife is fixed on one side of the knife holder and covers the guide groove, and one end of the fixed knife with a cutting edge extends out of the end of the knife holder, the movable knife is in the shape of an elongated strip and is slidably inserted into the guide groove, and the movable knife fits the fixed knife, the elastic pressing sheet and the auxiliary spring sheet are both fixed on the other side of the knife holder, and the elastic pressing sheet is pressed against the side of the portion of the fixed knife extending out of the knife holder, and can pass between the fixed knife and the elastic pressing sheet when the movable knife extends out. The cutting edge of the fixed knife is the edge of the extending end, and the movable knife is stably arranged in the guide groove. When it extends out, the elastic pressing sheet can act on the side of the movable knife, so that the movable knife fits the fixed knife more closely, thereby improving the thread trimming effect.

[0016] In the thread trimming mechanism of the sewing machine, a thread hooking notch is provided on one side edge of the movable knife, and a thread trimming groove is provided on one side surface of the movable knife along the length direction, one end of the thread trimming groove is connected to the thread hooking notch, and the other end of the notch edge is a cutting edge. When the movable knife is extended, the notch edge of the thread trimming groove and the cutting edge of the fixed knife can cut the thread, and the thread ends of the thread left on the movable knife can be pressed by the elastic pressing sheet.

[0017] Compared with the prior art, the thread trimming mechanism of the sewing machine has the following advantages:

[0018] 1. Since the sewing machine is also provided with an auxiliary spring sheet, the auxiliary spring sheet is pressed against the outer surface of the thread pressing end of the elastic pressing sheet under the action of its own elastic force, that is, the suture is pressed by the joint force of the elastic pressing sheet and the auxiliary spring sheet, and the stability and reliability are higher.

[0019] 2. When the elastic pressing plate ages or its elastic force weakens after being used for a period of time, the adjusting piece can be used to adjust and increase the pressing force of the auxiliary spring sheet on the elastic pressing plate, thereby compensating for the elastic force of the elastic pressing plate that decreases due to aging, ensuring that the suture is always pressed by sufficient force, and avoiding the suture falling off after cutting. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the partial three-dimensional structure of a sewing machine.

[0021] Figure 2 It is a partial three-dimensional structural schematic diagram of the thread trimming mechanism.

[0022] Figure 3 It is a partial three-dimensional structural diagram of the thread trimming mechanism from another perspective.

[0023] Figure 4 It is a side view of the partial structure of the thread trimming mechanism.

[0024] Figure 5 It is a partial structural sectional view of the thread trimming mechanism.

[0025] Figure 6 yes Figure 5 A magnified view of the structure at center.

[0026] Figure 7 This is a three-dimensional structural diagram of the moving knife.

[0027] In the figure, 1, casing; 11, presser wheel; 2, knife holder; 21, guide groove; 22, guide part; 3, fixed knife; 4, movable knife; 41, hook wire notch; 42, wire cutting groove; 5, elastic pressing piece; 51, wire pressing end; 511, elastic part; 512, wire pressing part; 52, fixing part; 53, through hole; 6, auxiliary spring piece; 61, connecting part; 62, adjusting part; 63, tilting part; 64, pressing piece part; 65, clearance hole; 7, adjusting member; 71, bolt; 72, adjusting knob; 8, installation spacing; 9, electromagnet; 91, mounting bracket. DETAILED DESCRIPTION

[0028] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0029] like Figure 1 As shown, a thread trimming mechanism of a sewing machine, the sewing machine comprises a housing 1, a presser wheel 11 is arranged on the housing 1, the presser wheel 11 is located at the sewing area, and a knife holder 2 is fixed on the housing 1, the knife holder 2 is in the shape of a long strip and tilted toward the sewing area. Figure 2 As shown, the thread cutting mechanism includes a fixed knife 3 fixed to the end of the knife holder 2 and a movable knife 4 slidably connected to the knife holder 2 along the length direction. The fixed knife 3 extends out of the end of the knife holder 2, and the edge of the extended end of the fixed knife 3 is a cutting edge. An electromagnet 9 is also fixed to the knife holder 2. The driving end of the electromagnet 9 is fixedly connected to the end of the movable knife 4. The movable knife 4 is in a long strip shape and fits with the fixed knife 3. When the movable knife 4 extends, it can hook the suture from the sewing area, and when it is retracted, it cooperates with the fixed knife 3 to cut the suture. Figure 3 , Figure 4As shown, the thread cutting mechanism also includes an elastic pressing sheet 5 and an auxiliary spring sheet 6, both of which are in the shape of long strips. The elastic pressing sheet 5 and the auxiliary spring sheet 6 are both metal sheets with approximately the same width, and the thickness of the auxiliary spring sheet 6 is greater than the thickness of the elastic pressing sheet 5, that is, the elastic force of the auxiliary spring sheet 6 is greater than the elastic force of the elastic pressing sheet 5. The elastic pressing sheet 5 is located on one side of the fixed knife 3, and one end of the elastic pressing sheet 5 is fixed to the end of the tool holder 2 away from the fixed knife 3, and the other end of the elastic pressing sheet 5 is a wire pressing end 51, and the wire pressing end 51 extends to the side of the fixed knife 3 and presses against the side of the part of the fixed knife 3 extending out of the tool holder 2. When the movable knife 4 retracts and cuts the suture, the elastic pressing sheet 5 can press the thread end of the suture against the side of the fixed knife 3. The auxiliary spring piece 6 is located on the side of the elastic pressing piece 5 facing away from the fixed knife 3. One end of the auxiliary spring piece 6 is fixed to the end of the tool holder 2 away from the fixed knife 3, and the other end is pressed against the side of the pressing end 51 of the elastic pressing piece 5 facing away from the fixed knife 3. The tool holder 2 is also provided with an adjusting part 7 which can adjust the pressing force of the auxiliary spring piece 6 on the elastic pressing piece 5.

[0030] Specifically, combined Figure 5 As shown, the elastic pressing sheet 5 includes a long elastic portion 511 and a fixed portion 52 and a wire pressing portion 512 respectively located at both ends of the elastic portion 511, the fixed portion 52 and the wire pressing portion 512 are both bent relative to the elastic portion 511, the fixed portion 52 is fixed on the tool holder 2, and the elastic portion 511 is inclined toward the side where the fixed knife 3 is located, so that the wire pressing portion 512 is pressed against the side of the fixed knife 3. The auxiliary spring piece 6 includes a connecting portion 61, an adjusting portion 62, an inclined portion 63 and a pressing portion 64 in sequence along the length direction. The connecting portion 61 is abutted against the fixed portion 52 of the elastic pressing sheet 5, and the connecting portion 61 and the fixed portion 52 are fixed to the tool holder 2 by the same screw. The adjusting portion 62 is arched toward the side away from the fixed knife 3. One end of the inclined portion 63 is connected to the adjusting portion 62, and the other end is along the elastic portion 511 of the elastic pressing sheet 5 and inclined toward the side where the fixed knife 3 is located, so that the pressing portion 64 connected to the other end of the inclined portion 63 is pressed against the side of the pressing line portion 512 of the elastic pressing sheet 5 facing away from the fixed knife 3. There is a gap between the inclined portion 63 and the elastic portion 511 of the elastic pressing sheet 5, and the gap gradually becomes smaller along the direction from the adjusting portion 62 to the pressing portion 64.

[0031] Combination Figure 6 As shown, the adjusting member 7 includes a bolt 71 and an adjusting knob 72. A through hole 53 is provided on the fixing portion 52 of the elastic pressing piece 5. A clearance hole 65 is provided on the adjusting portion 62 of the auxiliary spring sheet 6. The bolt 71 passes through the clearance hole 65 and the through hole 53 and is fixed to the tool holder 2. A mounting spacing 8 is formed between the arched adjusting portion 62 and the fixing portion 52. The adjusting knob 72 is arranged within the mounting spacing 8 and is screwed onto the bolt 71. The adjusting portion 62 is located between the adjusting knob 72 and the head of the bolt 71. The adjusting knob 72 abuts against and supports the auxiliary spring sheet 6.

[0032] Combination Figure 7As shown, a guide groove 21 is provided on one side of the tool holder 2 along the length direction, and the guide groove 21 extends to the end of the tool holder 2. The fixed knife 3 is in a sheet shape and is fixedly attached to the side surface of the end of the tool holder 2. The fixed knife 3 covers part of the guide groove 21, and has an upwardly protruding guide portion 22 in the guide groove 21 near the fixed knife 3. A mounting frame 91 is fixed to the driving end of the electromagnet 9, and the mounting frame 91 is located in the guide groove 21. One end of the movable knife 4 is fixed on the mounting frame 91, and the other end is attached to the upper side surface of the guide portion 22 and extends from the end of the tool holder 2, and the movable knife 4 is attached to the fixed knife 3. When the movable knife 4 is extended, it can pass between the fixed knife 3 and the elastic pressing sheet 5. A hooking notch 41 is provided on one side edge of the movable knife 4, and a thread cutting groove 42 is provided along the length direction on the side of the movable knife 4 facing the fixed knife 3. One end of the thread cutting groove 42 is connected to the hooking notch 41, and the cutting edge of the notch edge at the other end can hook the suture through the hooking notch 41 when the movable knife 4 is extended, and the notch edge of the thread cutting groove 42 and the cutting edge of the fixed knife 3 cut the suture when it is retracted, and the suture thread end left on the movable knife 4 can be pressed by the elastic pressing plate 5.

[0033] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0034] Although the terms such as housing 1, presser wheel 11, and knife holder 2 are used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the utility model; interpreting them as any additional restrictions is contrary to the spirit of the utility model.

Claims

1. A thread trimming mechanism for a sewing machine, the sewing machine comprising a housing (1) and a knife frame (2) fixed on the housing (1), the thread trimming mechanism comprising a fixed knife (3) arranged on the knife frame (2), a movable knife (4) and an elastic pressing sheet (5) located on one side of the fixed knife (3) and having a thread pressing end (51), wherein the thread pressing end (51) of the elastic pressing sheet (5) can press the cut thread against the side of the fixed knife (3), characterized in that: The thread cutting mechanism also includes a long strip of auxiliary spring sheet (6), one end of which is fixed on the knife holder (2), and the other end of which is pressed against the side of the wire pressing end (51) of the elastic pressing sheet (5) facing away from the fixed knife (3). The knife holder (2) is also provided with an adjusting member (7) capable of adjusting the pressing force of the auxiliary spring sheet (6) on the elastic pressing sheet (5).

2. The thread trimming mechanism of a sewing machine according to claim 1, characterized in that: The elastic pressing sheet (5) is in the shape of an elongated strip, and one end of the elastic pressing sheet (5) is a fixing portion (52) fixed on the tool holder (2), and the other end of the elastic pressing sheet (5) is the above-mentioned wire pressing end (51).

3. The thread trimming mechanism of a sewing machine according to claim 2, characterized in that: The wire pressing end (51) comprises an elastic portion (511) connected to the fixing portion (52) at one end and a wire pressing portion (512) connected to the other end of the elastic portion (511), and the auxiliary spring sheet (6) is pressed against the side of the elastic portion (511) facing away from the fixed knife (3) or the side of the wire pressing portion (512) facing away from the fixed knife (3).

4. The thread trimming mechanism of a sewing machine according to claim 3, characterized in that: The elastic pressing sheet (5) and the auxiliary spring sheet (6) are both metal sheets with approximately the same width, and the thickness of the auxiliary spring sheet (6) is greater than the thickness of the elastic pressing sheet (5).

5. The thread trimming mechanism of a sewing machine according to claim 4, characterized in that: The auxiliary spring sheet (6) is located on the side of the elastic pressing sheet (5) facing away from the fixed knife (3), and one end of the auxiliary spring sheet (6) is fixedly attached to the fixed portion (52), and the other end is bent toward the side where the fixed knife (3) is located and pressed against the wire pressing end (51) of the elastic pressing sheet (5).

6. The thread trimming mechanism of a sewing machine according to claim 3, 4 or 5, characterized in that: The adjusting member (7) comprises a bolt (71) and an adjusting knob (72); a clearance hole (65) is provided on the auxiliary spring sheet (6); a through hole (53) is provided on the elastic pressing sheet (5); the bolt (71) passes through the clearance hole (65) and the through hole (53) and is fixed on the tool holder (2); the adjusting knob (72) is screwed onto the bolt (71), and the adjusting knob (72) is located between the elastic pressing sheet (5) and the auxiliary spring sheet (6).

7. The thread trimming mechanism of a sewing machine according to claim 6, characterized in that: The auxiliary spring piece (6) comprises a connecting portion (61) fixedly connected to the knife holder (2) and an adjusting portion (62) connected to the connecting portion (61) and arched toward a side away from the fixed knife (3); the above-mentioned clearance hole (65) is arranged on the adjusting portion (62); there is a mounting spacing (8) between the adjusting portion (62) and the fixing portion (52) of the elastic pressing piece (5); the adjusting knob (72) is located within the mounting spacing (8); and the adjusting portion (62) is located between the adjusting knob (72) and the head of the bolt (71).

8. The thread trimming mechanism of a sewing machine according to claim 7, characterized in that: The auxiliary spring sheet (6) further comprises an inclined portion (63) connected to the adjusting portion (62) and a pressing portion (64) connected to the inclined portion (63); a gap is provided between the inclined portion (63) and the elastic portion (511) of the elastic pressing sheet (5); and the pressing portion (64) is pressed against the pressing line portion (512) of the elastic pressing sheet (5).

9. The thread trimming mechanism of a sewing machine according to any one of claims 1 to 7, characterized in that: The knife holder (2) is in the shape of an elongated strip, and a guide groove (21) is provided on one side of the knife holder (2) along the length direction. The fixed knife (3) is fixed on one side of the knife holder (2) and covers the guide groove (21), and one end of the fixed knife (3) having a cutting edge extends out of the end of the knife holder (2). The movable knife (4) is in the shape of an elongated strip and is slidably arranged in the guide groove (21), and the movable knife (4) fits the fixed knife (3). The elastic pressing sheet (5) and the auxiliary spring sheet (6) are both fixed on the other side of the knife holder (2), and the elastic pressing sheet (5) is pressed against the side of the portion of the fixed knife (3) extending out of the knife holder (2), so that when the movable knife (4) extends out, it can pass between the fixed knife (3) and the elastic pressing sheet (5).

10. The thread trimming mechanism of a sewing machine according to claim 9, characterized in that: A thread hooking notch (41) is provided on one side edge of the movable knife (4), and a thread cutting groove (42) is provided on one side surface of the movable knife (4) along the length direction. One end of the thread cutting groove (42) is connected to the thread hooking notch (41), and the other end is a cutting edge at the edge of the notch.

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