Thread trimming device with double moving knife mechanism and sewing machine

Abstract

The present technical scheme belongs to the technical field of sewing machines, and specifically relates to a thread trimming device with a double movable knife mechanism and a sewing machine, comprising a first movable knife mechanism, which comprises a first driving member and a first movable knife blade, the first movable knife blade is provided with a needle hole, the needle hole is used for the sewing needle to pass through in the sewing starting stage, and is used for stretching the sewing thread to a specified position; a second movable knife mechanism, which comprises a second driving member and a second movable knife blade, and is used for cooperating with the first movable knife blade to cut the thread; wherein the output ends of the first movable knife mechanism and the second movable knife mechanism are coaxially arranged, the blade of the second movable knife blade is movably fitted on the upper surface of the first movable knife blade, and the blade of the second movable knife blade cuts the thread when it slides over the cutting edge of the front part of the thread guide groove of the first movable knife blade; and further comprising: a thread clamping piece, which is arranged on the sewing machine frame and is located on the inner side of the movement path of the first movable knife blade; the thread is clamped when the needle hole of the first movable knife blade moves to the thread clamping piece position.

Description

Technical Field

[0001] The present technical solution relates to the technical field of sewing machines, and in particular to a thread trimming device with a double-moving knife mechanism and a sewing machine. Background Art

[0002] The sewing machine is mainly composed of a base (i.e., the casing and bottom plate), a needle bar mechanism, a feeding mechanism, a thread hook mechanism, a presser foot mechanism, a thread trimming mechanism and accessories. The sewing materials are sewed together through the reasonable coordination of the movements of various mechanisms and the circulation work.

[0003] During the sewing machine's sewing start and end stages, long thread ends will remain on the surface of the fabric; the thread ends will form bird's nest-like thread ends on the sewn clothing, affecting the quality of the entire clothing. In order to ensure the quality of the clothing, the thread ends must be trimmed manually, which increases the intensity of labor and affects production efficiency.

[0004] In order to improve sewing efficiency, automatic thread cutting mechanisms are usually used in sewing equipment, which not only makes sewing smoother, but also reduces thread ends in clothes, improving the efficiency of subsequent finishing. CN202322683791.X discloses a single-action knife anti-bird nest thread cutting mechanism and a sewing machine. This technical solution can cut off the excessively long part of the sewing thread at the sewing start stage, and can also cut the sewing thread after the sewing process is completed.

[0005] In the actual application of this technical solution, the thread ends left on the surface of the fabric are still not ideal. For some ordinary clothes, the length of the thread ends can basically be reduced without the need for secondary manual trimming. However, for some high-end clothes, the length of the thread ends left on the fabric is still relatively obvious and still needs to be trimmed manually. Summary of the invention

[0006] The purpose of the technical solution is to provide a sewing machine that can achieve better sewing effect and has shorter thread ends after thread cutting, and a thread cutting device with a double movable knife mechanism. By coaxially arranging the output ends of the first movable knife mechanism and the second movable knife mechanism, the blade of the first movable knife blade is movably fitted on the upper surface of the second movable knife blade. The two blades cooperate with each other to obtain a better sewing effect, and at the same time solve the problems of loose stitches and too long thread ends after thread cutting in the original sewing machine.

[0007] The purpose of this technical solution is achieved in this way:

[0008] A thread trimming device with a double movable knife mechanism comprises: a first movable knife mechanism, which comprises a first driving member and a first movable knife blade arranged at the output end of the first driving member, the first movable knife blade is provided with a needle hole, the needle hole is used for the sewing needle to pass through in the sewing starting stage, and the first movable knife blade is used to stretch the sewing thread to a specified position; a second movable knife mechanism, which comprises a second driving member and a second movable knife blade arranged at the output end of the second driving member, and the second movable knife blade is used to cooperate with the first movable knife blade to trim the thread; wherein, the output ends of the first movable knife mechanism and the second movable knife mechanism are coaxially arranged, the blade edge of the second movable knife blade is movably attached to the upper surface of the first movable knife blade, and when the blade edge of the second movable knife blade slides over the cutting edge of the front part of the thread guide groove of the first movable knife blade, the first movable knife blade and the second movable knife blade cooperate to cut the sewing thread;

[0009] It also includes: a thread clamp, which is arranged on the sewing machine frame and located on the inner side of the movement path of the first movable knife blade; when the needle hole of the first movable knife blade moves to the thread clamp position, the thread clamp cooperates with the first movable knife blade to clamp the sewing thread in the needle hole.

[0010] Preferably, the thread trimming device also includes an air suction device, which is arranged outside the movement path of the first movable knife blade and is used to suck away the cut sewing thread; the air suction port of the air suction device is arranged outside the thread clamping plate and faces the thread clamping plate.

[0011] Preferably, the first moving knife mechanism also includes a first transmission assembly, which is controlled by the first driving member and drives the first moving knife blade to rotate, and the first transmission assembly includes: a first movable block, which is arranged at the output end of the first driving member, and a first abutment block is protruding from the end side of the first movable block; a first crank, which is hinged on the end cover of the first driving member and has a first slide groove at the front end, and the first abutment block is movably engaged in the first slide groove; a first transmission rod, whose front end is arranged at the rear end of the first crank; and a first tool holder, which is rotatably sleeved on the rotary shuttle shaft and connected to the rear end of the first transmission rod; wherein, the first moving knife blade is arranged on the first tool holder, and the first movable block pushes the first crank to rotate through the first abutment block, and then drives the first tool holder to rotate through the first transmission rod.

[0012] Preferably, the first crank is in a "V" shape, and a first hinge shaft is arranged on the lower side of the middle part of the first crank, and the first hinge shaft is rotatably mounted on the end cover of the first driving member; a first slide groove is formed on one side wall of the first crank, and a first output rod is formed on the other side wall, and the upper end of the first output rod is hinged to the first transmission rod.

[0013] Preferably, a needle threading hole and a thread guide groove are provided on the first movable knife blade, and the needle threading hole and the thread guide groove are arranged along the rotation direction of the first movable knife blade; the needle threading hole is provided at the tail portion of the first movable knife blade, and is used for allowing the sewing needle to pass through and hook the thread at the same time; the thread guide groove is provided on the front side of the needle threading hole and is connected to the outside world, and is used for hooking the thread.

[0014] Preferably, the second moving knife mechanism also includes a second transmission assembly, which is controlled by the second driving member and is used to drive the second moving knife blade to rotate, the second transmission assembly includes: a second movable block, which is arranged at the output end of the second driving member, and a second abutment block is protruding from the end side of the second movable block; a second crank, a front end of which has a second annular groove, and the second abutment block movably abuts in the second annular groove; a second transmission block, which is arranged at the rear end of the second crank; a second transmission rod, a front end of which is arranged at the rear end of the second transmission block; and a second tool holder, which is rotatably sleeved on the rotary shuttle shaft and connected to the rear end of the second transmission rod; wherein, the second moving knife blade is arranged on the second tool holder, and the second movable block pushes the second crank to rotate through the second abutment block, and then drives the second tool holder to rotate through the second transmission block and the second transmission rod.

[0015] Preferably, the second moving knife mechanism also includes: a second limiting portion, which is arranged on the second transmission block, and the end side of the second limiting portion movably abuts against the sewing machine frame; and a second torsion spring, which is sleeved outside the second crank, with its front end clamped in the sewing machine frame and its rear end abutting against the second limiting portion, so that the limit always has a tendency to move toward the sewing machine frame.

[0016] Preferably, the front end of the second movable blade has a cutting edge; the cutting edge cooperates with the cutting edge at the front of the wire guide groove to cut the wire.

[0017] A sewing machine comprises a double-moving knife thread trimming device, a sewing machine frame, a sewing device, a presser foot lifting device and / or a stitch length adjusting device; the second driving member has a first output end and a second output end, the first output end drives the second moving knife blade, and the second output end drives the presser foot lifting device and the stitch length adjusting device.

[0018] Compared with the prior art, the technical solution has the following outstanding and beneficial technical effects:

[0019] 1. The thread trimming device designed in the technical solution has a first movable knife mechanism and a second movable knife mechanism that are independent and can cooperate with each other. The first movable knife mechanism is used to stretch the sewing thread to a specified position before thread trimming, and the second movable knife mechanism is used to trim the thread. In this way, straightening the sewing thread can make the sewing or thread trimming effect better, and make the stitches at the starting and closing of the needles on the fabric more compact. At the same time, the thread clamp can cooperate with the first movable knife blade to automatically clamp the sewing thread, so that the stitches are more stable during sewing.

[0020] 2. The thread clamp designed in this technical solution can clamp the cut sewing thread, and the suction device can suck away the cut sewing thread, which can ensure that the cut sewing thread will not affect normal sewing, and at the same time ensure the internal cleanliness of the sewing machine working mechanism.

[0021] 3. The first moving knife mechanism designed in the present technical solution includes a "V"-shaped first crank, which is hinged on the end cover of the first driving member. This arrangement is because the space below the sewing machine frame is extremely narrow. This structure can not only realize the transmission of the first moving knife mechanism, but also make the trajectory of the first moving knife blade consistent when the first driving member rotates forward and reverse. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a sewing machine.

[0023] Figure 2 This is a structural diagram of the technical solution.

[0024] Figure 3 It is a structural schematic diagram of the first moving knife mechanism.

[0025] Figure 4 It is a structural schematic diagram of the second moving knife mechanism.

[0026] Figure 5 It is a schematic diagram of the structure of the wire clamp and the air suction device.

[0027] Figure 6 This is a diagram of the state when the thread clamp is clamping the sewing thread.

[0028] Figure 7 It is a schematic diagram of the structure of the first tool holder and the second tool holder.

[0029] Figure 8 for Figure 1 Enlarged view of point A in the middle.

[0030] Reference numerals: 1, first moving knife mechanism; 2, second moving knife mechanism; 3, first driving member; 4, first moving knife blade; 41, needle hole; 42, wire guide groove; 43, cutting edge; 5, first transmission assembly; 51, first movable block; 52, first abutment block; 53, first crank; 531, first hinge shaft; 532, first output rod; 54, first slide groove; 55, first transmission rod; 56, first knife holder; 6, second driving member; 7, second moving knife blade; 71, cutting edge; 8, second transmission assembly; 81 , the second movable block; 82, the second abutment block; 83, the second crank; 84, the second annular groove; 85, the second transmission block; 86, the second transmission rod; 87, the second tool holder; 88, the second limiter; 89, the second torsion spring; 9, the thread clamp; 10, the air suction device; 101, the air suction port; 11, the sewing machine frame; 111, the oil box; 12, the sewing device; 13, the presser foot lifting device; 141, the rotary hook shaft; 142, the sewing needle; 15, the first output terminal; 16, the second output terminal; 17, the clamped sewing thread. DETAILED DESCRIPTION

[0031] The specific implementation of the technical solution is further described in detail below with reference to the accompanying drawings.

[0032] like Figure 1-8 As shown, a thread trimming device with a double movable knife mechanism comprises a first movable knife mechanism 1 and a second movable knife mechanism 2. The first movable knife mechanism 1 and the second movable knife mechanism 2 are arranged horizontally and compactly, which can save the internal space of the sewing machine and provide installation space for other devices in the sewing machine. The first movable knife mechanism 1 comprises a first driving member 3, a first transmission assembly 5 and a first movable knife blade 4. The first driving member 3 is used to output power, the first transmission assembly 5 transmits power, and the first movable knife blade 4 is used to stretch the sewing thread to a specified position; the second movable knife mechanism 2 comprises a second driving member 6, a second transmission assembly 8 and a second movable knife blade 7. The second driving member 6 is used to output power, the second transmission assembly 8 transmits power, and the second movable knife blade 7 is used to cooperate with the first movable knife blade 4 to trim the thread. The first movable knife mechanism 1 and the second movable knife mechanism 2 have independent power sources and transmission assemblies, which can ensure that the thread trimming device will not have motion interference during operation.

[0033] Furthermore, the output ends of the first movable knife mechanism 1 and the second movable knife mechanism 2 are coaxially arranged and rotatably sleeved on the shuttle shaft 141 together, which can ensure the tightness of the fit between the first movable knife blade 4 and the second movable knife blade 7. At the same time, the first movable knife blade 4 and the second movable knife blade 7 move around the shuttle mechanism, and the sewing needle 142 moves above the shuttle mechanism (in order to clearly show the structure of the thread trimming device, the shuttle mechanism is not shown in the accompanying drawings), so the sewing needle 142 can pass through the first movable knife blade 4 and extend into the shuttle mechanism.

[0034] The rotation radius of the first movable blade 4 is slightly smaller than the rotation radius of the second movable blade 7, so that the cutting edge 71 of the second movable blade 7 can be movably fitted on the upper surface of the first movable blade 4. When the cutting edge 71 of the second movable blade 7 slides over the cutting edge 43 at the front end of the guide groove 42 of the first movable blade 4, it is the cutting position of the wire cutting device.

[0035] like Figure 3 As shown, the first transmission assembly 5 includes a first movable block 51, a first crank 53, a first transmission rod 55 and a first tool holder 56. The first movable block 51 is arranged at the output end of the first driving member 3. The first driving member 3 can be set as a motor. The first movable block 51 rotates with the motor shaft. The middle part of the first crank 53 is hinged on the end cover of the first driving member 3. The front end has a first slide groove 54, and the rear end extends outward. The front end of the first movable block 51 is protruding to set a first abutment block 52, and the first abutment block 52 is movably engaged in the first slide groove 54. When the first abutment When the block 52 moves in the first slide groove 54, the front end of the first crank 53 swings, thereby driving the first crank 53 to rotate around the hinge point between it and the end cover of the first driving member 3, thereby driving the rear end of the first crank 53 to follow the swing, and the first tool holder 56 is sleeved on the rotary shuttle shaft 141 and can rotate around the rotary shuttle shaft 141. The first transmission rod 55 is used to connect the rear end of the first crank 53 and the first tool holder 56. At the same time, the first movable blade 4 is set on the first tool holder 56 by a screw. At this point, the first driving member 3 can drive the first movable blade 4 to rotate.

[0036] Furthermore, the first crank 53 is "V"-shaped, and a first hinge shaft 531 is arranged on the lower side of the middle part of the first crank 53. The first hinge shaft 531 is rotatably mounted on the end cover of the first driving member 3. A first slide groove 54 is formed on one side wall of the first crank 53, and a first output rod 532 is formed on the other side wall. The upper end of the first output rod 532 is hinged to the first transmission rod 55. Since the space below the sewing machine frame 11 is extremely narrow, the "V"-shaped first crank 53 is directly hinged on the end cover of the first driving member 3, which can not only realize the transmission of the first moving knife mechanism 1, but also save the internal space of the sewing machine frame 11. At the same time, the setting method of the first slide groove 54 can ensure that the movement trajectory of the first moving knife blade 4 is consistent when the first driving member 3 rotates forward and reverse.

[0037] Furthermore, a needle hole 41 and a thread guide groove 42 are provided on the first movable knife blade 4. The needle hole 41 is convenient for the sewing machine to cut the thread when starting the needle, and the thread guide groove 42 is convenient for the sewing machine to cut the thread when closing the needle. The needle hole 41 and the thread guide groove 42 are arranged along the rotation direction of the first movable knife blade 4. The needle hole 41 is provided at the tail of the first movable knife blade 4 for allowing the sewing needle 142 to pass through and hook the thread at the same time. The thread guide groove 42 is provided on the front side of the needle hole 41 and is connected to the outside world for hooking the thread. The front end of the thread guide groove 42 has a cutting edge 43. When the sewing thread is in the needle hole 41 or the thread guide groove 42, it will not be cut when there is no pressure. The sewing thread will not be cut until the cutting edge 71 of the second movable knife blade 7 coincides with the cutting edge 43.

[0038] Furthermore, the front end of the guide groove 42 is recessed and formed on the surface of the first movable knife blade 4, and it can penetrate the first movable knife blade 4 or not penetrate the first movable knife blade 4. The function of the front end of the guide groove 42 is to provide an escape space for the sewing thread to be pushed in, ensuring that the sewing thread will not be worn off during the pushing process.

[0039] [Variation] The needle hole 41 and the lead groove 42 can be connected to each other and to the outside world.

[0040] like Figure 3 As shown, the main reason why the first transmission component 5 adopts the cooperation mode of the slider and the slide groove is that the first movable blade 4 needs to rotate forward and reverse during actual work. Relative to the motor, it is necessary to ensure that the trajectory of the first movable blade 4 is consistent, so the cooperation mode of the slider and the slide groove is adopted.

[0041] like Figure 4 As shown, the second transmission assembly 8 includes a second movable block 81, a second crank 83, a second transmission block 85, a second transmission rod 86 and a second tool holder 87. The second movable block 81 is arranged at the output end of the second driving member 6. The second driving member 6 can be set as a motor. The second movable block 81 rotates with the motor shaft. The second crank 83 is rotatably arranged on the sewing machine frame 11 through the shaft sleeve. The front end of the second crank 83 has a second annular groove 84, and the rear end is provided with a second transmission block 85, so the movement direction of the second annular groove 84 is consistent with the movement direction of the second transmission block 85. Synchronously, the second movable block 81 is provided with a second abutment block 82 protruding from the end side, and the second abutment block 82 is movably abutted in the second annular groove 84. When the second abutment block 82 moves in the second annular groove 84, the second transmission block 85 follows the movement, and the second tool holder 87 is sleeved on the rotary shuttle shaft 141 and can rotate around the rotary shuttle shaft 141. The second transmission rod 86 is used to connect the second transmission block 85 and the second tool holder 87. At the same time, the second movable knife blade 7 is set on the second knife holder 87 by a screw, so that the second driving member 6 can drive the second movable knife blade 7 to rotate.

[0042] Furthermore, the second transmission assembly 8 adopts the matching mode of the crank and the annular groove mainly because this matching mode is more suitable for the movement mode of the second movable blade 7.

[0043] like Figure 4 and Figure 8 As shown, the second movable knife mechanism 2 also includes a second limiting portion 88 and a second torsion spring 89. The second limiting portion 88 is arranged on the second transmission block 85. The second limiting portion 88 can also be integrally formed with the second transmission block 85. The end side of the second limiting portion 88 movably abuts against the sewing machine frame 11 to limit the rotation angle of the second transmission block 85. The second torsion spring 89 is sleeved outside the second crank 83, and its front end is fixedly clamped in the sewing machine frame 11, and the rear end abuts against the second limiting portion 88. The second torsion spring 89 is used to make the second limiting portion 88 always have a tendency to move toward the sewing machine frame 11, thereby realizing the resetting of the second transmission block 85 and the second limiting portion 88.

[0044] like Figure 5 and Figure 6 As shown, the thread trimming device also includes a thread clamping piece 9 and an air suction device 10. The thread clamping piece 9 is fixedly arranged on the sewing machine frame 11. The front end of the thread clamping piece 9 extends toward the rotary shuttle mechanism and is located on the inner side of the movement path of the first movable knife blade 4. When the sewing needle 142 first needles in and moves up to a certain height, the upper thread will remain in the needle hole 41 of the first movable knife blade 4, and the first needle will not hook the bottom line in the rotary shuttle mechanism. Then, when the first movable knife blade 4 moves to the outside of the thread clamping piece 9, the needle hole 41 drives the upper thread to the position of the thread clamping piece 9, and the thread clamping piece 9 cooperates with the thread hole 4 of the first movable knife blade 4. The needle hole 41 clamps the sewing thread. At this time, the first movable knife blade 4 and the second movable knife blade 7 both stop rotating, the cloth moves and the sewing needle 142 sews the second stitch. Since the clamped sewing thread 17 is in the position shown in the figure, one end of it is clamped, and the stitches of the sewing needle 142 will not become loose when the second stitch is sewing. After the sewing of the second stitch is completed, the first movable knife blade 4 and the second movable knife blade 7 continue to rotate until the thread cutting is completed, which can ensure that the sewing thread will not loosen on the surface of the cloth. Therefore, the design of the thread clamp 9 can obtain better sewing and thread cutting effects.

[0045] The suction device 10 is arranged outside the movement path of the first movable knife blade 4, and the suction port 101 of the suction device 10 is aligned with the clamping position of the thread clamping plate 9. The suction port 101 of the suction device 10 is arranged outside the thread clamping plate 9 and faces the thread clamping plate 9, so that the cut sewing thread can be sucked in the first time.

[0046] like Figure 7 As shown, the first tool holder 56 and the second tool holder 87 are both mounted on the outside of the rotary hook shaft 141 through a shaft sleeve, a gasket is arranged between the first tool holder 56 and the second tool holder 87, and a locking plate is arranged on the outer side of the first tool holder 56, which can stably install the first tool holder 56 and the second tool holder 87 on the shaft sleeve.

[0047] like Figure 1 As shown, a sewing machine includes a thread trimmer device with a double movable knife mechanism, a sewing machine frame 11, a sewing device 12, a presser foot lifting device 13 and / or a stitch length adjusting device, wherein the presser foot lifting device 13 is arranged beside the oil box 111 of the sewing machine frame 11, the stitch length adjusting device is not shown in the figure, and the presser foot lifting device 13 and the stitch length adjusting device are both related to the prior art and will not be described in detail herein. The second driving member 6 has a first output end 15 and a second output end 16, the first output end 15 drives the second movable knife blade 7, and the second output end 16 drives the presser foot lifting device 13 and the stitch length adjusting device, and the sewing device 12 includes a rotary shuttle shaft 141 and a sewing needle 142, the front end of which is penetrated through the output ends of the first movable knife mechanism 1 and the second movable knife mechanism 2, and the rear end drives the sewing needle 142 to move vertically.

[0048] The above shows and describes the basic principle and main features of the technical solution and the advantages of the technical solution. The technicians in this industry should understand that the technical solution is not limited by the above embodiments. The above embodiments and the description are only to illustrate the principle of the technical solution. Without departing from the spirit and scope of the technical solution, the technical solution will have various changes and improvements, which fall within the scope of the technical solution to be protected. The scope of protection claimed by the technical solution is defined by the attached claims and their equivalents.

Claims

1. A thread trimming device with a double moving knife mechanism, characterized in that: include: A first movable knife mechanism (1), comprising a first driving member (3) and a first movable knife blade (4) arranged at the output end of the first driving member (3), wherein the first movable knife blade (4) is provided with a needle hole (41), the needle hole (41) being used for a sewing needle (142) to pass through during the sewing start stage, and the first movable knife blade (4) is used for stretching the sewing thread to a specified position; A second movable knife mechanism (2), comprising a second driving member (6) and a second movable knife blade (7) arranged at an output end of the second driving member (6), wherein the second movable knife blade (7) is used to cooperate with the first movable knife blade (4) to cut the thread; The output ends of the first movable knife mechanism (1) and the second movable knife mechanism (2) are coaxially arranged, the blade edge (71) of the second movable knife blade (7) is movably attached to the upper surface of the first movable knife blade (4), and when the blade edge (71) of the second movable knife blade (7) slides over the cutting edge (43) at the front of the wire guide groove (42) of the first movable knife blade (4), the first movable knife blade (4) and the second movable knife blade (7) cooperate to cut the sewing thread; Also includes: A thread clamp (9) which is arranged on a sewing machine frame (11) and is located inside the movement path of the first movable blade (4); When the needle threading hole (41) of the first movable blade (4) moves to the position of the thread clamping piece (9), the thread clamping piece (9) cooperates with the first movable blade (4) to clamp the sewing thread in the needle threading hole (41); The first movable knife mechanism (1) further comprises a first transmission assembly (5), which is controlled by the first driving member (3) and drives the first movable knife blade (4) to rotate. The first transmission assembly (5) comprises: A first movable block (51) is arranged at the output end of the first driving member (3), and a first abutment block (52) is protrudingly arranged on the end side of the first movable block (51); A first crank (53) is hinged on the end cover of the first driving member (3) and has a first slide groove (54) at the front end, and the first abutment block (52) is movably engaged in the first slide groove (54); A first transmission rod (55), the front end of which is arranged at the rear end of the first crank (53); and A first knife holder (56) is rotatably sleeved on the rotary hook shaft (141) and connected to the rear end of the first transmission rod (55); The first movable blade (4) is arranged on a first blade holder (56), the first movable block (51) drives the first crank (53) to rotate through the first abutment block (52), and then drives the first blade holder (56) to rotate through the first transmission rod (55); The first crank (53) is in a "V" shape, and a first hinge shaft (531) is provided on the lower side of the middle part of the first crank (53), and the first hinge shaft (531) is rotatably mounted on the end cover of the first driving member (3); A first sliding groove (54) is formed on one side wall of the first crank (53), and a first output rod (532) is formed on the other side wall. The upper end of the first output rod (532) is hinged to the first transmission rod (55).

2. A thread trimming device with a double moving knife mechanism according to claim 1, characterized in that: It also includes an air suction device (10), which is arranged outside the movement path of the first movable blade (4) and is used to suck away the cut sewing thread; The air suction port (101) of the air suction device (10) is arranged outside the wire clamping piece (9) and faces the wire clamping piece (9).

3. A thread trimming device with a double moving knife mechanism according to claim 2, characterized in that: The first movable blade (4) is provided with a needle threading hole (41) and a wire guide groove (42), and the needle threading hole (41) and the wire guide groove (42) are arranged along the rotation direction of the first movable blade (4); The needle hole (41) is provided at the tail of the first movable blade (4) and is used for the sewing needle (142) to pass through and hook the thread at the same time; The wire guide groove (42) is arranged on the front side of the needle threading hole (41) and is connected to the outside world for hooking the wire.

4. A thread trimming device with a double movable knife mechanism according to any one of claims 1 to 3, characterized in that: The second movable knife mechanism (2) further comprises a second transmission assembly (8), which is controlled by the second driving member (6) and is used to drive the second movable knife blade (7) to rotate, and the second transmission assembly (8) comprises: A second movable block (81) is arranged at the output end of the second driving member (6), and a second abutment block (82) is protrudingly arranged on the end side of the second movable block (81); A second crank (83) having a second annular groove (84) at its front end, and the second abutment block (82) movably abuts against the second annular groove (84); A second transmission block (85) disposed at the rear end of the second crank (83); A second transmission rod (86), the front end of which is arranged at the rear end of the second transmission block (85); and A second knife holder (87) is rotatably sleeved on the rotary hook shaft (141) and connected to the rear end of the second transmission rod (86); The second movable blade (7) is arranged on the second blade holder (87), and the second movable block (81) drives the second crank (83) to rotate through the second abutment block (82), thereby driving the second blade holder (87) to rotate through the second transmission block (85) and the second transmission rod (86).

5. A thread trimming device with a double-moving knife mechanism according to claim 4, characterized in that: The second moving knife mechanism (2) further comprises: A second limiting portion (88) is arranged on the second transmission block (85), and an end side of the second limiting portion (88) movably abuts against the sewing machine frame (11); and A second torsion spring (89) is sleeved outside the second crank (83), with its front end clamped in the sewing machine frame (11) and its rear end abutting against the second limiting portion (88), so as to ensure that the second limiting portion (88) always has a tendency to move toward the sewing machine frame (11).

6. A thread trimming device with a double-moving knife mechanism according to claim 5, characterized in that: The front end of the second movable blade (7) has a cutting edge (71); The knife edge (71) cooperates with the cutting edge (43) at the front of the wire guide groove (42) to cut the wire.

7. A sewing machine, characterized in that: A thread trimming device with a double-moving knife mechanism comprising any one of claims 1 to 6, and further comprising a sewing machine frame (11), a sewing device (12), a presser foot lifting device (13) and / or a stitch length adjusting device; The second driving member (6) has a first output end (15) and a second output end (16), wherein the first output end (15) drives the second movable knife blade (7), and the second output end (16) drives the presser foot lifting device (13) and the needle distance adjusting device.

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