Thread trimming structure of sewing machine

Abstract

The utility model provides a thread trimming structure of a sewing machine, and belongs to the technical field of sewing machines. The thread trimming mechanism solves the problems that in the prior art, a thread trimming mechanism of the sewing machine is long in thread trimming end and poor in thread trimming stability. According to the thread trimming structure of the sewing machine, the sewing machine comprises a machine base, a rotating shuttle shaft, a thread pressing piece, a needle plate with a needle falling hole and a movable cutter, the rotating shuttle shaft, the thread pressing piece, the needle plate and the movable cutter are arranged on the machine base, the movable cutter is provided with a thread hooking groove and can vertically swing around the rotating shuttle shaft, and the thread pressing piece can abut against the upper side edge of the thread hooking groove of the movable cutter. The needle plate is provided with a needle falling hole, the needle plate is further provided with a thread passing groove communicated with the needle falling hole, the thread trimming structure comprises a fixed cutter and an elastic thread blocking piece which are connected to the needle plate, a cutting edge of the fixed cutter is located in or below the thread passing groove, and the elastic thread blocking piece is blocked in front of the cutting edge of the fixed cutter. And the elastic wire blocking piece can generate elastic deformation under the action of external force and retract to the rear part of the blade of the fixed cutter. The thread trimming device has the advantages of being short in thread trimming end and good in thread trimming stability.

Description

Technical Field

[0001] This utility model belongs to the field of sewing machine technology and relates to a thread-cutting structure for a sewing machine. Background Technology

[0002] The thread-cutting mechanism is an important component of a sewing machine. For example, Chinese patent literature discloses a thread-cutting mechanism and sewing machine (application number: 201811350563.8), which includes a fixed blade with a fixed blade edge and a movable blade with a moving blade edge. The movable blade can move in a direction close to or away from the fixed blade. The movable blade has a thread-separating groove. The moving blade edge and the thread-separating groove are arranged opposite to each other in the direction of movement of the movable blade. When cutting the thread after sewing, the thread-separating groove of the movable blade allows the bottom thread and top thread to enter, and the movable blade drives the bottom thread and top thread to move towards the fixed blade until the moving blade edge engages with the fixed blade edge and cuts the bottom thread and top thread. When starting to sew, the thread-separating groove of the movable blade allows the top thread end to enter, and the movable blade drives the top thread end to move towards the fixed blade until the moving blade edge engages with the fixed blade edge and cuts the top thread end.

[0003] The thread-cutting mechanism of this sewing machine has the following shortcomings during use: the contact point (i.e., the thread-cutting point) between the moving blade and the fixed blade of the thread-cutting mechanism is far from the needle plate, resulting in a long thread end after cutting. In addition, the thread-cutting mechanism of this sewing machine is driven by an electromagnet and has a complex transmission structure, which makes it impossible to control the thread-cutting time and position, resulting in poor thread-cutting stability. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a thread-cutting structure for sewing machines. The technical problem this invention aims to solve is addressing the issues of excessively long thread ends and poor thread-cutting stability in existing sewing machine thread-cutting mechanisms.

[0005] The objective of this utility model can be achieved through the following technical solutions:

[0006] A thread-cutting structure for a sewing machine, the sewing machine including a machine base and a rotary hook shaft, a thread presser, a needle plate with a needle drop hole, and a movable blade with a thread hook groove that can swing up and down around the rotary hook shaft, respectively disposed on the machine base. The thread presser can press against the upper edge of the thread hook groove of the movable blade, and the needle plate also has a thread guide groove communicating with the needle drop hole. This thread-cutting structure includes a fixed blade and an elastic thread stop connected to the needle plate. The fixed blade's cutting edge is located inside or below the thread guide groove, and the elastic thread stop blocks the front of the fixed blade's cutting edge. Furthermore, the elastic thread stop can elastically deform and retract behind the fixed blade's cutting edge under external force.

[0007] When the sewing machine makes its first stitch, the needle, carrying the thread, passes downward through the hook groove on the moving blade. Then, the needle moves upward. When the needle moves upward to above the needle plate, the moving blade, carrying the thread in the hook groove, swings downward toward the pressure plate. The pressure plate of the sewing machine's thread-cutting structure can press against the upper edge of the hook groove of the moving blade to clamp the thread end. The downward swing of the moving blade drives the thread at the needle drop hole to force the elastic thread stop to move toward the fixed blade until it contacts the fixed blade and is cut (at this time, the elastic thread stop undergoes elastic deformation and retracts behind the fixed blade). This achieves thread cutting at the needle plate, resulting in a short thread end. This not only ensures that the starting thread end remaining on the fabric is very short, but also that the thread cutting structure relying solely on the fixed blade is simple and has good thread cutting stability.

[0008] In addition, the cut thread ends can be sucked away by the suction device to prevent them from getting stuck, thereby improving the bird nest prevention effect and the working reliability of the thread cutting structure; when not cutting the thread, the elastic thread stop block is in front of the fixed blade to prevent the top thread from accidentally touching the fixed blade and being cut during the sewing process.

[0009] In the thread-cutting structure of the sewing machine described above, the surface of the upper edge of the moving blade thread-hooking groove is uneven. This creates a friction surface (preferably a toothed surface) on the upper edge of the moving blade thread-hooking groove, allowing the pressure plate to better contact the moving blade surface and clamp the thread end tightly, preventing the thread end from coming loose.

[0010] In the thread-cutting structure of the sewing machine described above, the elastic thread stop is a spring arranged along the length of the thread guide groove. One end of the spring is fixed to the needle plate or the fixed blade, and the other end of the spring is connected to a baffle arranged along the width of the thread guide groove. The baffle is located in front of the fixed blade, and its two ends are located on both sides of the thread guide groove. When no external force is applied, the baffle's position in front of the fixed blade prevents the thread from accidentally contacting and being cut by the fixed blade during sewing. When an external force is applied, the thread can drive the baffle to compress the spring and move the baffle behind the fixed blade, allowing the thread to contact and be cut by the fixed blade.

[0011] In the thread-cutting structure of the sewing machine described above, the spring is fixedly connected to the lower end face of the fixed blade along its length. The lower end face of the fixed blade also has a guide plate with a U-shaped cross-section that covers the outside of the spring. The guide plate guides and limits the movement of the spring, allowing the baffle connected to the free end of the spring to move smoothly behind the blade of the fixed blade.

[0012] In the thread-cutting structure of the sewing machine described above, the elastic thread stop is a second elastic sheet disposed below the fixed blade. One end of the second elastic sheet is fixed to the needle plate or the fixed blade, and the other end of the second elastic sheet is disposed adjacent to the front of the fixed blade and is curved downwards. When not subjected to external force, the free end of the second elastic sheet is located in front of the fixed blade, which can prevent the thread from accidentally touching the fixed blade and being cut during sewing. When subjected to external force, the second elastic sheet can undergo elastic deformation and retract to the rear of the fixed blade, so that the thread can contact the fixed blade and be cut.

[0013] A thread-cutting structure for a sewing machine, the sewing machine including a machine base and a rotary hook shaft, a pressure plate, a needle plate with a needle drop hole, and a movable blade with a thread hook groove that can swing up and down around the rotary hook shaft, respectively disposed on the machine base. The pressure plate can press against the upper edge of the thread hook groove of the movable blade, and the needle plate also has a thread guide groove communicating with the needle drop hole. This thread-cutting structure includes a fixed blade and an elastic thread stop connected to the needle plate. The blade of the fixed blade is located inside or below the thread guide groove, and the elastic thread stop blocks the front of the blade of the fixed blade. Furthermore, the elastic thread stop can undergo elastic deformation under external force and form a thread guide gap with the groove wall of the thread guide groove.

[0014] When the sewing machine makes its first stitch, the needle, carrying the thread, passes downward through the hook groove on the moving blade. Then, the needle moves upward. When the needle moves upward to above the needle plate, the moving blade, carrying the thread in the hook groove, swings downward toward the pressure plate. The pressure plate of the sewing machine's thread-cutting structure can press against the upper edge of the hook groove of the moving blade to clamp the thread end. The downward swing of the moving blade drives the thread at the needle drop hole to push open the elastic thread stop and move toward the fixed blade until it contacts the fixed blade and is cut (at this time, the elastic thread stop undergoes elastic deformation and forms a thread passage gap with the groove wall of the thread passage groove, and the thread passes through the elastic thread stop through the thread passage gap). This achieves thread cutting at the needle plate, resulting in a short thread end. This not only ensures that the starting thread end remaining on the fabric is very short, but also that the thread cutting structure relying solely on the fixed blade is simple and has good thread cutting stability.

[0015] In addition, the cut thread ends can be sucked away by the suction device to prevent them from getting stuck, thereby improving the bird nest prevention effect and the working reliability of the thread cutting structure; when not cutting the thread, the elastic thread stop block is in front of the fixed blade to prevent the top thread from accidentally touching the fixed blade and being cut during the sewing process.

[0016] In the thread-cutting structure of the sewing machine described above, the surface of the upper edge of the moving blade thread-hooking groove is uneven. This creates a friction surface (preferably a toothed surface) on the upper edge of the moving blade thread-hooking groove, allowing the pressure plate to better contact the moving blade surface and clamp the thread end tightly, preventing the thread end from coming loose.

[0017] In the thread-cutting structure of the sewing machine described above, the elastic thread stop is a first elastic sheet disposed within the thread guide groove. The first elastic sheet is U-shaped or J-shaped, with its open end facing the fixed blade. One end of the first elastic sheet is fixed to the groove wall on one side of the thread guide groove, and the other end abuts against the groove wall on the other side of the thread guide groove. When not subjected to external force, the first elastic sheet abutting against the groove wall of the thread guide groove can prevent the top thread from accidentally contacting the fixed blade and being cut during sewing. When subjected to external force, the first elastic sheet can undergo elastic deformation and form a thread guide gap with the groove wall of the thread guide groove, allowing the top thread to pass through the thread gap, be blocked by the first elastic sheet, and then contact the fixed blade before being cut.

[0018] Compared with existing technologies, the advantages of the thread-cutting structure of this sewing machine are as follows: The pressure plate of the thread-cutting structure can press against the upper edge of the moving knife hook groove to clamp the thread end. The downward swing of the moving knife drives the thread at the needle hole to push open the elastic thread stop and move towards the fixed knife blade until it contacts the fixed knife blade and is cut. This achieves thread cutting at the needle plate, which not only ensures that the starting thread end remaining on the fabric is very short, but also allows the cut thread end to be sucked away by the suction device, avoiding thread end retention, thereby improving the anti-bird nest effect and the working reliability of the thread-cutting structure. Attached Figure Description

[0019] Figure 1 This is a top view of a partial structural diagram of the thread-cutting structure of the sewing machine in Embodiment 1.

[0020] Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle.

[0021] Figure 3 This is a partial three-dimensional structural diagram of the thread-cutting structure of the sewing machine in Embodiment 1, viewed from below.

[0022] Figure 4 This is a top view of a partial structural diagram of the thread-cutting structure of the sewing machine in Embodiment 2 (when the first elastic piece abuts against the wall of the thread groove).

[0023] Figure 5 This is a top view of a partial structural diagram of the thread-cutting structure of the sewing machine in Embodiment 2 (when the first elastic sheet undergoes elastic deformation and forms a thread-passing gap with the wall of the thread-passing groove).

[0024] Figure 6 This is a three-dimensional structural diagram of the first elastic piece of the thread-cutting structure of the sewing machine in Embodiment 2.

[0025] Figure 7This is a partial three-dimensional structural diagram of the thread-cutting structure of the sewing machine in Embodiment 3, viewed from below.

[0026] Figure 8 This is a three-dimensional structural diagram of the thread-cutting mechanism of this sewing machine when the thread presser and the moving blade are in contact.

[0027] Figure 9 This is a three-dimensional structural diagram of the moving blade of the thread-cutting mechanism of this sewing machine.

[0028] In the diagram, 1 is the machine base; 2 is the rotary hook; 3 is the pressure plate; 4 is the needle plate; 4a is the needle drop hole; 4b is the thread guide groove; 5 is the moving knife; 5a is the thread hook groove; 6 is the fixed knife; 6a is the guide limit plate; 7 is the elastic thread stop; 71 is the spring; 72 is the first elastic plate; 73 is the second elastic plate; 8 is the thread guide gap; and 9 is the baffle. Detailed Implementation

[0029] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0030] Example 1

[0031] A thread-cutting structure for a sewing machine, as shown in the reference. Figure 1-3 , Figure 8 and Figure 9 The sewing machine includes a base 1 and a rotary hook shaft, a pressure plate 3, a needle plate 4 with a needle drop hole 4a, and a movable blade 5 with a thread hook groove 5a that can swing up and down around the rotary hook shaft, all respectively disposed on the base 1. The pressure plate 3 can press against the upper edge of the thread hook groove 5a of the movable blade 5. The needle plate 4 is also provided with a thread guide groove 4b that communicates with the needle drop hole 4a. The thread cutting structure includes a fixed blade 6 and an elastic thread stop 7 respectively connected to the needle plate 4. The blade of the fixed blade 6 is located inside or below the thread guide groove 4b. The elastic thread stop 7 blocks the front of the blade of the fixed blade 6, and the elastic thread stop 7 can undergo elastic deformation and retract to the rear of the blade of the fixed blade 6 under the action of external force.

[0032] Reference Figure 1 , Figure 2 and Figure 3 Specifically, the elastic wire stop 7 is a spring 71 arranged along the length direction of the wire groove 4b. One end of the spring 71 is fixed to the needle plate 4 or the fixed blade 6, and the other end of the spring 71 is connected to a baffle 9 arranged along the width direction of the wire groove 4b. The baffle 9 is located in front of the blade of the fixed blade 6, and the two ends of the baffle 9 are respectively located on both sides of the wire groove 4b.

[0033] Reference Figure 1 , Figure 2 and Figure 3Furthermore, the spring 71 is fixedly connected to the lower end face of the fixed blade 6 along the length direction of the fixed blade 6. The lower end face of the fixed blade 6 also has a guide limiting plate 6a. The cross-section of the guide limiting plate 6a is U-shaped and covers the outside of the spring 71.

[0034] Reference Figure 8 and Figure 9 In this embodiment, the surface of the upper edge of the groove 5a of the moving blade 5 is preferably uneven, and preferably has a toothed surface.

[0035] The following section explains the working principle of the thread-cutting mechanism of this sewing machine:

[0036] Before the sewing machine starts sewing the first stitch, the moving blade 5 moves upward, so that the end of the hook groove 5a on the moving blade 5 that is away from the blade edge moves directly below the needle. Alternatively, during the process of the sewing machine starting to sew the first stitch and the needle moving downward, the moving blade 5 moves simultaneously, so that the end of the hook groove 5a on the moving blade 5 that is away from the blade edge moves directly below the needle.

[0037] The sewing machine makes its first stitch, with the needle carrying the thread downwards through the hook groove 5a on the moving blade 5. Then, the needle moves upwards. When the needle moves upwards to above the needle plate 4, the moving blade 5, carrying the thread in the hook groove 5a, swings downwards towards the pressure plate 3. This allows the pressure plate 3 to press against the upper edge of the hook groove 5a of the moving blade 5, clamping the thread end. As the moving blade 5 continues to swing downwards (during which the pressure plate 3 and the moving blade 5 keep the thread end clamped), the thread located at the needle drop hole 4a moves along the thread passage groove 4b and drives the baffle 9 to compress the spring 71 towards the fixed blade edge (it should be noted that the free end of the spring 71 is adjacent to the fixed blade). The movement of the blade, i.e., the short distance between the free end of spring 71 and the fixed blade, allows the thread to easily drive the baffle 9 to compress spring 71. Additionally, a thinner diameter spring steel wire can be used to further compress spring 71. The thread is cut only after contacting the fixed blade (the cooperative structure of baffle 9 and spring 71 prevents the thread from accidentally contacting the fixed blade and being cut during sewing). This achieves thread cutting at needle plate 4, ensuring that the remaining thread end on the fabric is very short, and that the cut thread end is sucked away by a suction device, preventing thread residue and improving the anti-bird's nest effect and the reliability of the thread cutting structure.

[0038] Example 2

[0039] This embodiment is basically the same in structure and principle as Embodiment 1, except that it includes a thread-cutting structure for a sewing machine, as described above. Figure 4-6 , Figure 8 and Figure 9The sewing machine includes a base 1 and a rotary hook shaft, a pressure plate 3, a needle plate 4 with a needle drop hole 4a, and a movable blade 5 with a hook groove 5a that can swing up and down around the rotary hook shaft, all respectively disposed on the base 1. The pressure plate 3 can press against the upper edge of the hook groove 5a of the movable blade 5. The needle plate 4 is also provided with a thread guide groove 4b that communicates with the needle drop hole 4a. The thread cutting structure includes a fixed blade 6 and an elastic thread stop 7 respectively connected to the needle plate 4. The blade of the fixed blade 6 is located inside or below the thread guide groove 4b. The elastic thread stop 7 blocks the front of the blade of the fixed blade 6, and the elastic thread stop 7 can undergo elastic deformation under the action of external force to form a thread guide gap 8 between itself and the groove wall of the thread guide groove 4b.

[0040] Reference Figure 4 Specifically, the elastic wire stop 7 is a first elastic sheet 72 disposed in the wire guide groove 4b. The elastic sheet is U-shaped or J-shaped. The open end of the first elastic sheet 72 is disposed facing the blade of the fixed knife 6. One end of the first elastic sheet 72 is fixed to the groove wall on one side of the wire guide groove 4b, and the other end of the first elastic sheet 72 abuts against the groove wall on the other side of the wire guide groove 4b.

[0041] Reference Figure 8 and Figure 9 In this embodiment, the surface of the upper edge of the groove 5a of the moving blade 5 is preferably uneven, and preferably has a toothed surface.

[0042] The following section explains the working principle of the thread-cutting mechanism of this sewing machine:

[0043] Before the sewing machine starts sewing the first stitch, the moving blade 5 moves upward, so that the end of the hook groove 5a on the moving blade 5 that is away from the blade edge moves directly below the needle. Alternatively, during the process of the sewing machine starting to sew the first stitch and the needle moving downward, the moving blade 5 moves simultaneously, so that the end of the hook groove 5a on the moving blade 5 that is away from the blade edge moves directly below the needle.

[0044] The sewing machine makes its first stitch, with the needle carrying the thread downwards through the hook groove 5a on the moving blade 5. Then, the needle moves upwards. When the needle reaches above the needle plate 4, the moving blade 5, carrying the thread in the hook groove 5a, swings downwards towards the pressure plate 3. This allows the pressure plate 3 to press against the upper edge of the hook groove 5a of the moving blade 5, clamping the thread end. As the moving blade 5 continues to swing downwards (during which the pressure plate 3 and the moving blade 5 consistently clamp the thread end), the thread at the needle drop hole 4a moves along the thread passage groove 4b, forcing the free end of the first elastic plate 72 towards the fixed end, thus causing the first elastic plate... The first elastic piece 72 undergoes elastic deformation and forms a thread passage gap 8 with the groove wall of the thread passage groove 4b, allowing the top thread to pass through the thread gap 8, be blocked by the first elastic piece 72, and be cut after contacting the fixed blade (when not subjected to external force, the first elastic piece 72 abuts against the groove wall of the thread passage groove 4b to prevent the top thread from accidentally touching the fixed blade and being cut during sewing). This achieves thread cutting at the needle plate 4, which not only ensures that the starting thread left on the fabric is very short, but also allows the cut thread to be sucked away by the suction device, avoiding thread retention and thus improving the anti-bird nest effect and the working reliability of the thread cutting structure.

[0045] Example 3

[0046] This embodiment is basically the same as embodiment one in structure and principle, except that: (Refer to...) Figure 7-9 The elastic guide 7 is a second elastic sheet 73 disposed below the fixed blade 6. One end of the second elastic sheet 73 is fixed to the needle plate 4 or the fixed blade 6, and the other end of the second elastic sheet 73 is disposed adjacent to the front of the blade of the fixed blade 6 and is curved downward.

[0047] The following section explains the working principle of the thread-cutting mechanism of this sewing machine:

[0048] Before the sewing machine starts sewing the first stitch, the moving blade 5 moves upward, so that the end of the hook groove 5a on the moving blade 5 that is away from the blade edge moves directly below the needle. Alternatively, during the process of the sewing machine starting to sew the first stitch and the needle moving downward, the moving blade 5 moves simultaneously, so that the end of the hook groove 5a on the moving blade 5 that is away from the blade edge moves directly below the needle.

[0049] When the sewing machine makes its first stitch, the needle, carrying the thread, passes downward through the hook groove 5a on the moving blade 5. Then, the needle moves upward. When the needle moves upward above the needle plate 4, the moving blade 5, carrying the thread in the hook groove 5a, swings downward toward the pressure plate 3. This allows the pressure plate 3 to press against the upper edge of the hook groove 5a of the moving blade 5, clamping the thread end. As the moving blade 5 continues to swing downward (during which the pressure plate 3 and the moving blade 5 keep the thread end clamped), the thread located at the needle drop hole 4a moves along the thread passage groove 4b, forcing the free end of the second elastic plate 73 to move. Moving downwards causes the second elastic sheet 73 to elastically deform and retract behind the blade of the fixed blade 6, allowing the top thread to contact and be cut by the blade (when not subjected to external force, the free end of the second elastic sheet 73 bending downwards is located in front of the blade of the fixed blade, which can prevent the top thread from accidentally touching the blade of the fixed blade and being cut during sewing). This achieves thread cutting at the needle plate 4, which not only ensures that the starting thread left on the fabric is very short, but also allows the cut thread to be sucked away by the suction device, preventing thread from being left behind, thereby improving the anti-bird nest effect and the working reliability of the thread cutting structure.

[0050] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A thread trimming structure of a sewing machine including a machine base (1) and a rotating hook shaft, a presser foot (3), a needle plate (4) having a drop needle hole (4a), and a moving knife (5) having a thread hooking groove (5a) and being able to swing up and down around the rotating hook shaft, which are respectively provided on the machine base (1), characterized in that, The pressing piece (3) can be pressed against the upper side edge of the hooking groove (5a) of the moving cutter (5), the needle plate (4) is further provided with a thread passing groove (4b) communicated with the needle falling hole (4a), the thread cutting structure comprises a fixed cutter (6) and an elastic thread blocking piece (7) connected to the needle plate (4) respectively, the cutting edge of the fixed cutter (6) is located in or below the thread passing groove (4b), the elastic thread blocking piece (7) is blocked in front of the cutting edge of the fixed cutter (6), and the elastic thread blocking piece (7) can be elastically deformed and retracted to the rear of the cutting edge of the fixed cutter (6) under the action of external force.

2. The thread trimming structure of a sewing machine according to claim 1, wherein The surface of the upper side edge of the hooking groove (5a) of the moving cutter (5) is uneven.

3. The thread trimming structure of a sewing machine according to claim 1 or 2, wherein The elastic thread blocking piece (7) is a spring (71) arranged along the length direction of the thread passing groove (4b), one end of the spring (71) is fixedly connected to the needle plate (4) or the fixed cutter (6), the other end of the spring (71) is connected with a baffle (9) arranged along the width direction of the thread passing groove (4b), the baffle (9) is located in front of the cutting edge of the fixed cutter (6), and the two ends of the baffle (9) are located on the two sides of the thread passing groove (4b) respectively.

4. The thread trimming structure of a sewing machine according to claim 3, wherein The spring (71) is fixedly connected to the lower end surface of the fixed cutter (6) along the length direction of the fixed cutter (6), and the lower end surface of the fixed cutter (6) is further provided with a guide limiting plate (6a), the cross section of the guide limiting plate (6a) is in the shape of a trident and covers the outside of the spring (71).

5. The thread trimming structure of a sewing machine according to claim 1 or 2, wherein The elastic thread blocking piece (7) is a second elastic piece (73) arranged below the fixed cutter (6), one end of the second elastic piece (73) is fixedly connected to the needle plate (4) or the fixed cutter (6), and the other end of the second elastic piece (73) is arranged in front of the cutting edge of the fixed cutter (6) and is in the shape of a downward bending arc.

6. A thread trimming structure of a sewing machine including a machine base (1) and a rotating hook shaft, a presser foot (3), a needle plate (4) having a drop needle hole (4a), and a moving knife (5) having a thread hooking groove (5a) and being able to swing up and down about the rotating hook shaft, which are respectively provided on the machine base (1), characterized in that, The pressing piece (3) can be pressed against the upper side edge of the hooking groove (5a) of the moving cutter (5), the needle plate (4) is further provided with a thread passing groove (4b) communicated with the needle falling hole (4a), the thread cutting structure comprises a fixed cutter (6) and an elastic thread blocking piece (7) connected to the needle plate (4) respectively, the cutting edge of the fixed cutter (6) is located in or below the thread passing groove (4b), the elastic thread blocking piece (7) is blocked in front of the cutting edge of the fixed cutter (6), and the elastic thread blocking piece (7) can be elastically deformed and retracted to the rear of the cutting edge of the fixed cutter (6) under the action of external force.

7. The thread trimming structure of a sewing machine according to claim 6, wherein The surface of the upper side edge of the hooking groove (5a) of the moving cutter (5) is uneven.

8. The thread trimming structure of a sewing machine according to claim 6 or 7, wherein The elastic thread blocking piece (7) is a first elastic piece (72) arranged in the thread passing groove (4b), the elastic piece is in the shape of U or J, the opening end of the first elastic piece (72) is arranged towards the cutting edge of the fixed cutter (6), one end of the first elastic piece (72) is fixedly connected to the groove wall on one side of the thread passing groove (4b), and the other end of the first elastic piece (72) abuts against the groove wall on the other side of the thread passing groove (4b).

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