Sewing machine with double movable cutters for trimming threads

Abstract

The technical scheme belongs to the technical field of sewing machines, and particularly relates to a double-moving-cutter thread trimming sewing machine which comprises a rack, a thread trimming mechanism and a rotating shuttle mechanism. The thread trimming mechanism comprises a first movable cutter assembly, a second movable cutter assembly and a driving assembly; the first movable cutter assembly and the second movable cutter assembly are rotationally arranged on the outer side of the matched rotating shuttle mechanism in a sleeving mode. The driving assembly drives the first movable cutter assembly to rotate between a first position and a second position around the axis and drives the second movable cutter assembly to move between a third position and a fourth position around the rotating axis. The first movable cutter assembly comprises a first thread trimming movable cutter, and the first thread trimming movable cutter is provided with a thread hole groove allowing a machine needle to penetrate through and hooking a sewing thread in the sewing starting stage and a first thread hooking groove allowing the sewing thread to be hooked in the ending stage; the second movable cutter assembly comprises a second thread trimming movable cutter; the thread hole groove or the first thread hooking groove hooks the sewing thread, the second thread trimming movable cutter is driven to rotate around the axis to abut against the surface of the first thread trimming movable cutter, the cutting edges of the two thread trimming movable cutters coincide to cut off the sewing thread, thread ends are reduced, and production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sewing machines, and in particular to a sewing machine with double-action cutting blades and thread trimmers. Background Art

[0002] A sewing machine is a machine that uses sewing thread to form one or more stitches on the material to be sewn, so that one or more layers of material are interwoven or sewn together. It is usually composed of a base (i.e., a machine casing and a bottom plate), a needle bar mechanism, a feeding mechanism, a thread hook mechanism, a presser foot mechanism, a thread trimming mechanism and accessories, and each mechanism works in a cycle.

[0003] During the starting and finishing stages of the sewing process, long thread ends are often left on the surface of the fabric. The thread ends produced during the starting process often appear in the shape of a bird's nest, which damages the neatness of the appearance of the clothing and directly reduces the overall quality standards of the clothing. The thread ends are finely trimmed manually, and the additional manual processing steps increase labor costs and affect the overall efficiency of the production line.

[0004] For example, Chinese patent CN105734851A discloses a thread cutting device for a sewing machine, which includes a lower cutter unit, an upper cutter unit and a drive unit. The drive unit is hinged to the upper cutter unit and the lower cutter unit respectively, and drives the cutting edges of the upper cutter and the lower cutter to overlap near the center of the needle for cutting by swinging.

[0005] The above-mentioned thread cutting device can cut out excess thread ends, but the problem of thread ends remaining on the surface of the fabric has not yet reached an ideal state. For clothing production with higher requirements, the thread ends are still relatively obvious, and manual secondary fine trimming is still required to optimize the final quality of the clothing. The processing is cumbersome, which reduces production efficiency and needs to be improved. Summary of the invention

[0006] In order to improve the problem that a large amount of thread ends are left after the existing thread cutting device cuts the thread, which requires secondary manual processing and reduces production efficiency, this technical solution provides a sewing machine with a double-action thread cutting knife.

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

[0008] A double-action thread-cutting sewing machine comprises a frame, a thread-cutting mechanism, and a rotary hook mechanism; the thread-cutting mechanism is arranged on the frame and below the needle; the machine also comprises a presser foot lifting mechanism, which is arranged on the frame, and a presser foot lifting mechanism is provided at the lower portion of the presser foot lifting mechanism for lifting and pressing sewing material;

[0009] A cloth feeding mechanism, which is arranged on the frame (1) and located below the presser foot lifter, and is used for feeding the sewing material forward;

[0010] The thread cutting mechanism includes a first moving knife assembly, a second moving knife assembly, and a driving assembly. The driving assembly includes a first driving member and a second driving member;

[0011] Both the first moving knife assembly and the second moving knife assembly are rotatably sleeved outside the corresponding rotating hook mechanism;

[0012] The driving assembly drives the first moving knife assembly to rotate between a first position and a second position around the axis of the rotating hook mechanism, and drives the second moving knife assembly to move between a third position and a fourth position around the axis of the rotating hook mechanism;

[0013] The first moving knife assembly includes a first moving knife holder and a first thread cutting knife. The first moving knife holder includes a first crank, a first connecting rod, and a first ring portion. The two ends of the first connecting rod are respectively hinged to the first crank and the first ring portion, and the first thread cutting knife is arranged on the first ring portion;

[0014] The first thread cutting knife is provided with a thread hole groove for the needle to pass through and hook the sewing thread during the starting sewing stage, and a first thread hooking groove for hooking the sewing thread during the ending sewing stage. A first cutting edge is also arranged on the front side of the first thread cutting knife;

[0015] The second moving knife assembly includes a second moving knife holder and a second thread cutting knife. The second moving knife holder includes a second crank, a second connecting rod, and a second ring portion. The two ends of the second connecting rod are respectively hinged to the second crank and the second ring portion, and the second thread cutting knife is arranged on the second ring portion;

[0016] A second cutting edge is arranged on the front side of the second thread cutting knife; during the rotation of the second thread cutting knife, it abuts against the surface of the first thread cutting knife, so that the first cutting edge of the first thread cutting knife and the second cutting edge of the second thread cutting knife cooperate to cut the sewing thread;

[0017] The thread clamp is arranged on the machine frame, between the first position and the second position, and adjacent to the second position; during the process of the first thread cutting knife resetting to the second position, the first thread cutting knife cooperates with the thread clamp to clamp the sewing thread in the thread hole groove.

[0018] Through the above technical solution, when the double-moving-knife thread cutting mechanism is in normal use, the first driving member drives the first crank to rotate. The other end of the first crank drives the hinged first connecting rod to swing, and the first connecting rod drives the hinged first ring portion to swing until the first ring portion is driven to rotate around the outside of the rotating hook mechanism. This rotational movement further drives the first thread cutting knife, and this tool completes the preparation and thread hooking actions before thread cutting.

[0019] Correspondingly, the structural design of the second moving cutter assembly is similar to that of the second moving cutter holder, but it is independently driven by the second driving member. When the second ring portion rotates to drive the second cutting moving knife to perform cutting and retracting during thread cutting, during the whole process, the two moving cutter assemblies work together to ensure the efficiency and precision of the thread cutting action.

[0020] The driving assembly drives the first cutting moving knife to switch between the first position and the second position. During the starting sewing stage, after it is in the first position, it hooks the sewing thread passed through by the first needle of the sewing machine through the thread hole groove and locks the thread segment. After switching to the second position, it pulls the sewing thread segment and places it between the two cutters for thread preparation; based on the fact that the two cutting moving knives each have an independent driving member and a transmission rod, and the two transmission rods are concentrically arranged. Similarly, the second cutting moving knife is driven to rotate from the third position to the fourth position around the same axis, and the cutting edges of the two cutting moving knives approach and overlap to precisely cut the sewing thread located between them.

[0021] After the feeding mechanism and the presser foot lifting mechanism cooperate for continuous sewing and reach the finishing stage, the first driving member drives the first cutting moving knife to hook the sewing thread into the first hook groove, and then repeats the above thread cutting process to achieve seamless thread cutting operation, ensuring the accuracy and efficiency of thread cutting, reducing the residual thread ends, eliminating the subsequent manual processing steps, and improving the automation degree and production efficiency of the overall production process.

[0022] Preferably, the driving assembly further includes a sleeve rod structure; the sleeve rod structure includes a first transmission rod and a second transmission rod disposed inside the first transmission rod or sleeved outside the first transmission rod;

[0023] The first driving member drives the first cutting moving knife through the first transmission rod; the second driving member drives the second cutting moving knife through the second transmission rod.

[0024] Through the above technical solution, the first driving member drives the first transmission rod to drive the first cutting moving knife in the first moving cutter assembly to rotate around the axis, and the second driving member also drives the second cutting moving knife to rotate. The dual power source setting with independent driving improves the overall operation efficiency and accuracy. The nested sleeve rod structure design not only effectively saves space but also improves the compactness and stability of the structure.

[0025] Preferably, the first cutting moving knife is further provided with a second hook groove, and the second hook groove and the first hook groove are respectively located on both sides of the width of the first cutting moving knife;

[0026] When performing thread cutting in the finishing stage, the first cutting moving knife moves towards the direction of the sewing machine needle, and the tip of the first cutting moving knife passes through the thread loop of the sewing thread; the first hook groove and the second hook groove respectively hook the sewing threads on both sides of the first cutting moving knife;

[0027] A wire guiding groove I is arranged between the wire hole groove of the cutting moving knife I and the first cutting edge, and the wire hooking groove I is located in the middle of the wire guiding groove I.

[0028] Through the above technical solution, the wire hooking groove II hooks the sewing thread on the other side of the wire loop, increasing the length of the cut thread end on the cutting moving knife I, reducing the operation of re-arranging the thread, improving the use efficiency, and the wire guiding groove I is used for accommodating the sewing thread to prevent the cutting moving knife II from pressing the sewing thread when it slides against the cutting moving knife I.

[0029] Preferably, the thread cutting mechanism further includes a first transmission component, which includes a first crank and a second crank movably arranged on the first crank;

[0030] The other end of the first crank is connected to the drive shaft of the first drive member, and the end of the second crank far from the first crank is fixed to the first transmission rod;

[0031] A sliding groove is provided on the end face of the second crank on the side close to the first crank, and a sliding block is correspondingly fixed at the swinging end of the first crank, and the sliding block is arranged in the sliding groove to realize sliding guidance;

[0032] The second crank is provided with a limiting portion, which is fixed at one end of the sliding groove far from the fixed end of the second crank for restricting the sliding block from falling off the sliding groove;

[0033] The swinging of the first crank drives the first transmission rod to rotate, and the other end of the first transmission rod directly or indirectly drives the first moving knife assembly.

[0034] Through the above technical solution, the first transmission component is connected between the first transmission rod and the first drive member for power transmission. The motor shaft of the first drive member drives the first crank to swing. A sliding block is fixed at the other end of the first crank and slides along the groove direction of the sliding groove to guide the movement of the second crank. Therefore, the first transmission rod will rotate with the movement of the second crank, so as to drive the first moving knife assembly by the first transmission rod.

[0035] The limiting portion of the second crank is fixed at one end of the sliding groove far from the connection and fixed end with the first crank, to prevent the sliding block from accidentally falling off the sliding groove due to various factors (such as vibration, impact, etc.) during the transmission process, avoiding the risk of falling off, and thus ensuring the continuity and safety of the transmission.

[0036] Preferably, the thread cutting mechanism further includes a second transmission component, which includes a third crank and a swinging cam arranged on the third crank;

[0037] One end of the third crank is fixed on the drive shaft of the second drive member, and an adjusting portion is arranged at the other swinging end of the third crank close to the swinging cam. The adjusting portion acts on the swinging cam, so that the third crank transmits power to the second transmission rod.

[0038] Through the above technical solution, the second transmission component is arranged between the second transmission rod and the second driving member to achieve efficient power transmission. The motor shaft of the second driving member serves as a power source to drive the third crank arm to swing periodically. The adjusting portion provided at the end of the third crank arm is in close cooperation with the swinging cam. By means of rolling, sliding or rotating of the adjusting portion, relative movement is generated with the swinging cam, so as to achieve effective power transmission, and then drive the second transmission rod to rotate, thereby realizing that the second transmission rod drives the second moving cutter assembly.

[0039] Preferably, an elastic member is provided on the second transmission rod and sleeved at one end of the second transmission rod where the second crank is provided;

[0040] The second crank is provided with a connecting block, and the elastic member is arranged between the connecting block and the machine frame, and its elastic force is used for the reset of the second thread-cutting moving cutter.

[0041] Through the above technical solution, the elastic member on the second transmission rod is connected between the connecting block and the machine frame. The connecting block provides stable support, and its elastic force enables the second transmission component to have a tendency to maintain the reset movement, prompting the second thread-cutting moving cutter to return to the initial position, ensuring the continuity and accuracy of the thread-cutting action.

[0042] Preferably, both ends of the second driving member have motor shafts, and the motor shafts include a first motor shaft and a second motor shaft. The first motor shaft drives the third crank arm, and the second motor shaft at the other end drives the presser foot to realize stitch length adjustment.

[0043] Through the above technical solution, the first motor shaft is specifically used to connect the third crank arm and serves as the power source of the second transmission component to realize the corresponding mechanical actions. The second motor shaft with other uses is arranged on the other side and is used to connect the presser foot mechanism to realize stitch length adjustment to meet different sewing requirements. Designing two motor shafts improves the overall performance of the driving member.

[0044] Preferably, the presser foot mechanism includes a driving cam, a connecting rod structure and a pressing rod structure, and the lower part of the connecting rod structure acts on the driving cam;

[0045] The other end of the connecting rod structure acts on the pressing rod structure, and the lower part of the pressing rod structure is provided with the presser foot. The driving cam is fixed to the second motor shaft, so that the second driving member drives the presser foot to operate.

[0046] Through the above technical solution, the second driving member drives the second motor shaft to rotate, the second motor shaft drives the driving cam to rotate synchronously, and the rotation of the driving cam is based on the inconsistency of the protrusions on its outer peripheral wall, so that a plurality of transmission rods in the link structure are driven to swing synchronously, and then the other end of the link structure acts on the pressure rod structure, realizing the lifting or lowering of the pressure rod structure, driving the lifting and pressing foot to perform the lifting and pressing action on the sewing material, and facilitating the stability of the sewing material during sewing.

[0047] Preferably, the feeding mechanism includes: a feed dog assembly, which includes a dog frame and feed dogs, and the feed dogs are fixed on the dog frame;

[0048] A lifting dog assembly, which includes a lifting dog seat hinged to the dog frame and a shaft rod arranged on the lifting dog seat, the shaft rod is rotatably installed on the machine frame, and the lifting dog seat drives the dog frame to move up and down;

[0049] A tooth-changing assembly, which includes a tooth-changing seat, a tooth-changing bracket arranged on the tooth-changing seat, a feed link, a feed crank and a feed motor, and the tooth-changing seat is hinged to the other end of the dog frame far from the lifting dog seat;

[0050] The crank end of the tooth-changing bracket is hinged to the end of the feed link, the other end of the feed link is hinged to the end of the feed crank, and the other end of the feed crank is connected to the driving end of the feed motor, so that the feed motor drives the feed crank to swing, for driving the dog frame to swing left and right.

[0051] Through the above technical solution, the output shaft of the feed motor drives the feed crank to rotate, the feed crank drives the feed link to swing, the feed link drives the tooth-changing bracket to swing, the tooth-changing bracket drives the tooth-changing seat to swing, and then the left and right swing adjustment of the dog frame is realized. The shaft rod drives the lifting dog seat to swing, and the lifting dog seat drives the other end of the dog frame to move up and down, so as to realize the movement of the feed dogs on the fabric.

[0052] Preferably, a thread suction device is provided on the machine frame, and the discharge suction port of the thread suction device is received at the thread hole groove, and it is used to suck the thread end after cutting.

[0053] Through the above technical solution, after the cutting moving knife hooks the sewing thread to the second position, the thread clamping device presses the thread tightly against the inner wall of the thread hole groove and releases it after cutting. At this time, the thread suction device sucks the cut thread end through the discharge suction port for collection and processing, avoiding scattering in the working area and ensuring the normal operation of the equipment.

[0054] The prominent and beneficial technical effects of this technical solution compared with the prior art are:

[0055] 1. In this technical solution, the driving component drives the thread-cutting knife one of the first moving knife component and the thread-cutting knife two of the second moving knife component to rotate, so that the two thread-cutting knives rotate axially around the outside of the rotary hook mechanism, realizing the operations of hooking the thread in the thread hole groove in the starting sewing stage, hooking the thread in the first thread-hooking groove and the second thread-hooking groove in the ending stage, and relatively approaching the two knives to cut the sewing thread, reducing the residual thread ends, and realizing automatic production and improving production efficiency.

[0056] 2. In this technical solution, the sleeve rod structure is used for transmission, which includes the first transmission rod and the second transmission rod. The first transmission rod is arranged inside the second transmission rod, and the two transmission rods are concentrically arranged and respectively correspond to the first moving knife component and the second moving knife component. This design simplifies the transmission structure and is beneficial to the precision of transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is the overall structural schematic diagram of this embodiment;

[0058] Figure 2 is of this embodiment Figure 1 schematic diagram from another perspective;

[0059] Figure 3 is the partial structural schematic diagram of the first moving knife component and the second moving knife component in the embodiment;

[0060] Figure 4 is the partial exploded schematic diagram of the first moving knife component in the embodiment;

[0061] Figure 5 is the partial exploded schematic diagram of the second moving knife component in the embodiment;

[0062] Figure 6 is the cooperation schematic diagram of the thread-cutting knife one and the thread-cutting knife two in the embodiment;

[0063] Figure 7 is the installation schematic diagram of the thread-cutting knife one and the thread-cutting knife two in the embodiment;

[0064] Figure 8 is the exploded structural schematic diagram of the first transmission component and the second transmission component in the embodiment;

[0065] Figure 9 is the operating structural schematic diagram of the first thread-hooking groove and the second thread-hooking groove for hooking the thread in the embodiment;

[0066] Figure 10 is the overall structural schematic diagram of the feeding mechanism in the embodiment;

[0067] Figure 11 is the overall structural schematic diagram of the presser foot lifting mechanism in the embodiment.

[0068] Reference numerals: 1, frame; 2, first moving knife assembly; 21, first thread cutting moving knife; 22, first moving knife holder; 221, first crank; 222, first connecting rod; 223, first ring part; 3, second moving knife assembly; 31, second thread cutting moving knife; 32, second moving knife holder; 321, second crank; 322, second connecting rod; 323, second ring part; 4, driving assembly; 41, first driving member; 42, second driving member; 5, sleeve rod structure; 51, first transmission rod; 52, second transmission rod; 6, thread hole groove; 71, first thread hook groove; 72, second thread hook groove; 8, first transmission assembly; 81, first crank arm; 82, second crank arm; 9, second transmission assembly; 91, third crank arm; 92, swing cam; 10, chute; 11, slider; 12, limiting part; 13, adjusting part; 14, torsion spring; 15, connecting block; 16, thread clamp; 17, wire arranging device; 181, first wire guiding groove; 182, second wire guiding groove; 19, presser foot lifting mechanism; 191, driving cam; 192, connecting rod structure; 193, presser rod structure; 20, presser foot; 23, feeding mechanism; 231, feed dog assembly; 2311, dog frame; 2312, feed dogs; 232, lifter assembly; 2321, lifter base; 2322, shaft rod; 233, tooth changing assembly; 2331, tooth changing base; 2332, tooth changing bracket; 2333, feeding connecting rod; 2334, feeding crank; 2335, feeding motor; 24, first motor shaft; 25, second motor shaft; 100, rotary hook mechanism; 200, sewing needle. Detailed implementation manners

[0069] The following further elaborates on the detailed implementation manners of the present technical solution in conjunction with the accompanying drawings.

[0070] Embodiment:

[0071] See Figure 1 and Figure 2 , a sewing machine with double moving knives for thread cutting, including a frame 1, which is the main part of the sewing machine device, and further includes a thread cutting mechanism installed below the frame 1. In this embodiment, the situation where a rotary hook mechanism 100 is installed inside the frame 1 and a sewing needle 200 is arranged above the frame 1 is shown. The rotary hook mechanism 100 is a prior art and will not be elaborated here. The lower end of the sewing needle 200 is used to pass through the sewing thread and can be lifted or lowered for use.

[0072] Refer to Figure 8The thread trimming mechanism includes a first movable knife assembly 2, a second movable knife assembly 3 and a driving assembly 4. The first movable knife assembly 2 and the second movable knife assembly 3 are both rotatably mounted on the outer peripheral side of the adapted rotary hook mechanism 100, with the rotary hook mechanism 100 as the rotation axis. The first movable knife assembly 2 is used to hook the sewing thread, and the second movable knife assembly 3 cooperates with the first movable knife assembly 2 as a thread trimmer. The driving assembly 4 includes a first driving member 41 and a second driving member 42. Both driving members can be motors. The first driving member 41 and the second driving member 42 respectively drive the first movable knife assembly 2 and the second movable knife assembly 3 indirectly through the sleeve rod structure 5 as a power source.

[0073] The second driving member 42 can be set as a dual-axis motor with motor shafts at both ends. The motor shafts include a first motor shaft 24 and a second motor shaft 25. The first motor shaft 24 drives the second movable knife assembly 3 to operate, and the second motor shaft 25 drives the presser foot lifting mechanism 19 to operate. The technical solution of how to share a motor between the two sets of mechanisms is an existing technology and will not be elaborated here.

[0074] The sleeve rod structure 5 includes a transmission rod 1 51 and a transmission rod 2 52. The transmission rod 2 52 is inserted into the transmission rod 1 51 or is sleeved on the outside of the transmission rod 1 51. This embodiment shows the situation where the transmission rod 1 51 is inserted into the transmission rod 2 52. The transmission rod 2 52 is a sleeve structure, and the transmission rod 1 51 is a rod core structure. The transmission rod 1 51 and the transmission rod 2 52 can rotate independently of each other and are concentrically arranged. The two ends of the transmission rod 1 51 respectively pass through the two ends of the transmission rod 2 52.

[0075] A first transmission assembly 8 is provided between the first driving member 41 and the transmission rod 51. The first transmission assembly 8 can transmit the rotation of the motor shaft of the first driving member 41 to the rotation of the transmission rod 51. The first transmission assembly 8 includes a first crank arm 81 and a second crank arm 82 movably provided on the first crank arm 81. One end of the first crank arm 81 is locked and fixed on the motor shaft of the first driving member 41. The second crank arm 82 is located on the side of the first crank arm 81 away from the first driving member 41. The first crank arm 81 swings to drive the second crank arm 82 to run synchronously. The specific transmission method The method is to fix a slider 11 at the other end of the first curved arm 81 protruding toward the second curved arm 82. The slider 11 is a rectangular block. The end face of the second curved arm 82 close to the first curved arm 81 is provided with a slide groove 10, which passes through both ends along the length direction of the second curved arm 82. The width of the slider 11 is adapted to the groove width of the slide groove 10, so that the slider 11 can be embedded in the slide groove 10 and slide along the length direction of the slide groove 10, pushing the second curved arm 82 to swing. Based on the fact that the other end of the second curved arm 82 is fixed on the transmission rod 51, the transmission rod 51 is driven to rotate.

[0076] The transmission is in the form of a slider 11 and a chute 10 assembly. Through the forward and reverse rotation of the motor, the forward and reverse motion trajectories of the thread trimming movable knife 21 are made consistent to ensure consistent knife traces.

[0077] The second curved arm 82 is provided with a limiting portion 12, which is fixed in the slide groove 10 and is located at an end of the groove away from the fixed end of the second curved arm 82. The limiting portion 12 in this embodiment is preferably a bolt structure for the slider 11 to abut against, and is used to limit the slider 11 from accidentally detaching from the through end of the slide groove 10, thereby improving the guiding stability.

[0078] A second transmission assembly 9 is provided between the second driving member 42 and the transmission rod 2 52. It is located on the same side as the first transmission assembly 8 and can transmit the rotation of the motor shaft of the second driving member 42 to the rotation of the transmission rod 2 52. The second transmission assembly 9 includes a third crank arm 91 and a swing cam 92. One end of the third crank arm 91 is locked and fixed on the motor shaft of the second driving member 42, and the other end is fixed with an adjusting portion 13, which protrudes toward the swing cam 92. The adjusting portion 13 can produce relative motion with the swing cam 92 by rolling, sliding or rotating. The swing cam 92 shown in this embodiment is provided with a cam groove, and the degree of protrusion of the inner wall of the groove is different. The adjusting portion 13 is embedded in the swing cam 92 and contacts the inner wall of the groove. When the third crank arm 91 rotates to drive the adjusting portion 13, the adjusting portion 13 contacts the inner wall of the groove to realize intermittent motion of the swing cam 92. Based on the fact that one end of the swing cam 92 is fixed to the end of the transmission rod 2 52, the transmission rod 2 52 is driven to rotate.

[0079] See also Figure 3 and Figure 4 The first movable knife assembly 2 includes a thread trimming movable knife 21 and a first movable knife holder 22, wherein the first movable knife holder 22 includes a first crank 221, a first connecting rod 222 and a first ring portion 223. The lower end of the first crank 221 is sleeved on the end of the transmission rod 51 away from the first driving member 41 and is fixed, and the other end is hinged to the lower end of the first connecting rod 222 upward, and the other end of the first connecting rod 222 is hinged to the first ring portion 223 to form two hinge points. The first ring portion 223 is rotatably sleeved on the rotary hook mechanism 100. When the transmission rod 51 rotates, the transmission rod 51 drives the first crank 221 to rotate, and the first driving member 41 drives the first connecting rod 222 to swing, so that the first connecting rod 222 drives the first ring portion 223 to rotate. The thread trimming movable knife 21 is installed on the first ring portion 223, which is in the shape of an arc sheet, so as to drive the thread trimming movable knife 21 to rotate and complete the switching between different positions.

[0080] See also Figure 3 and Figure 5, the second moving cutter assembly 3 is located at the rear side of the first moving cutter assembly 2, and it includes a second crank 321, a second connecting rod 322 and a second ring portion 323. The lower end of the second crank 321 is sleeved and fixed at one end of the second transmission rod 52 far away from the second driving member 42, and the other end thereof is hinged upward with the lower end of the second connecting rod 322. The other end of the second connecting rod 322 is hinged on the second ring portion 323, thereby forming two hinge points. The second ring portion 323 is rotatably sleeved on the rotating hook mechanism 100 and is adjacent to the first ring portion 223. When the second transmission rod 52 rotates, the second transmission rod 52 drives the second crank 321 to rotate, and the second driving member 42 drives the second connecting rod 322 to swing, so that the second connecting rod 322 drives the second ring portion 323 to rotate. Since the second cutting moving knife 31 is installed on the second ring portion 323 and is in an arc-shaped sheet shape, it realizes driving the first cutting moving knife 21 to rotate to complete the switching between different positions.

[0081] The second crank 321 is provided with a connecting block 15, which is located above the second crank 321. A torsion spring 14 is sleeved on one end of the second transmission rod 52 close to the second crank 321. The torsion spring 14 is respectively arranged between the connecting block 15 and the frame 1, and its elastic force acts on the second crank 321, so that the second crank 321 can quickly reset after the second transmission rod 52 disengages from the inner surface of the swing cam 92, so as to make the second cutting moving knife 31 maintain the tendency of resetting to the initial position.

[0082] The first cutting moving knife 21 is provided with a thread hole groove 6, a first thread hooking groove 71 and a second thread hooking groove 72. Each groove penetrates through the thickness direction of the first cutting moving knife 21. The thread hole groove 6 and the first thread hooking groove 71 are arranged along the rotation direction of the first cutting moving knife 21. The thread hole groove 6 is located away from the cutting edge tip of the first cutting moving knife 21. There is a first cutting edge with different flatness at the cutting edge tip. The thread hole groove 6 is used for the sewing needle 200 to pass through and hook the sewing thread during the starting sewing stage.

[0083] See Figure 9 , the first thread hooking groove 71 and the second thread hooking groove 72 are respectively located on the opposite sides of the middle part of the first cutting moving knife 21, and both have openings facing outwards. When the cutting edge tip passes through the thread loop, the openings on both sides are used to hook the sewing threads on both sides into the corresponding thread hooking grooves during the end sewing stage, so as to realize thread hooking. In this embodiment, it is shown that the first cutting moving knife 21 is provided with two wire grooves for accommodating the sewing thread. Among them, the first wire groove is located between the thread hole groove 6 and the first cutting edge, and covers the first thread hooking groove 71, guiding the sewing thread to the thread hole groove 6. The front edge of the first wire groove is provided with the first cutting edge. The front end of the first wire groove can be a through groove or a non-through groove. The other wire groove 2 corresponds to the second thread hooking groove 72 and is used to guide the sewing thread to the second thread hooking groove 72.

[0084] The second thread trimming movable knife 31 is arranged above the outer side of the first thread trimming movable knife 21, and the front end of the second thread trimming movable knife 31 is pressed against the upper surface of the first thread trimming movable knife 21 and slides. The front end of the second thread trimming movable knife 31 is provided with a second cutting edge. When the second thread trimming movable knife 31 and the first thread trimming movable knife 21 approach each other, the thread hole groove 6 or the thread hook groove 71 will bring the sewing thread to the second cutting edge. The sewing thread is not subjected to pressure on the first cutting edge and will not be cut until it coincides with the second cutting edge. The sewing thread will be cut, ensuring that the thread end is cut at the start of sewing and the thread is not broken at the end of sewing.

[0085] See also Figure 7 The frame 1 is also provided with a thread clamp 16, which is located on the inner side of the thread trimmer 21 and can be aligned with the thread hole slot 6. In the sewing stage, when the sewing thread is ready to be cut, the thread clamp 16 clamps the sewing thread passing through the thread hole slot 6 to the inner wall of the thread trimmer 21, locks the upper thread and stops supplying the upper thread to the needle 200 (the thread passing through the needle 200 of the sewing machine is the upper thread, and the thread in the shuttle mechanism 100 at the bottom of the sewing machine is the lower thread), so that the stitches of the subsequent second stitch are stable and not easy to fall apart after sewing.

[0086] The frame 1 is further provided with a wire arrangement device 17 , the discharge suction port of the wire arrangement device 17 is connected to the wire hole groove 6 , and is used to absorb the wire ends after the wires are cut.

[0087] See also Figure 10 The frame 1 is provided with a presser foot lifting mechanism 19, which includes a driving cam 191, a connecting rod structure 192 and a pressure rod structure 193. The driving cam 191 is fixed on the second motor shaft 25, driving the driving cam 191 to rotate, and its outer peripheral wall has different degrees of protrusion. The lower end of the connecting rod structure 192 acts on the driving cam 191, and the other end of the connecting rod structure 192 acts on the pressure rod structure 193, so that the protruding surface of the driving cam 191 can push the connecting rod structure 192 upward, thereby driving the pressure rod structure 193 to lift. Based on the lower end of the pressure rod structure 193, a presser foot lifting 20 is fixed, thereby realizing the lifting of the presser foot 20 or pressing down the sewing material.

[0088] See also Figure 11 The frame 1 is provided with a cloth feeding mechanism 23, which includes a cloth feeding dog assembly 231, a tooth lifting assembly 232 and a tooth changing assembly 233, wherein the cloth feeding dog assembly 231 includes a tooth rack 2311 and a cloth feeding tooth 2312, the tooth rack 2311 is located below the presser foot lifting 20, and is movably arranged relative to the frame 1, the cloth feeding tooth 2312 is fixed above the tooth rack 2311 and is aligned with the position of the presser foot lifting 20, and its upper end surface has a serrated structure.

[0089] The lifter component 232 can control the up-and-down movement of the rack 2311. Specifically, it includes a lifter base 2321 and a shaft rod 2322. The lifter base 2321 is fixed at one end of the shaft rod 2322. The shaft rod 2322 is rotatably connected to the frame 1 and is driven to rotate by a driving device. Its rotation drives the lifter base 2321 to swing. The other side of the lifter base 2321 is hinged to one end of the rack 2311, thereby driving the rack 2311 to move.

[0090] The tooth-changing component 233 can control the left-and-right swing of the rack 2311. Specifically, it includes a tooth-changing base 2331, a tooth-changing bracket 2332, a feeding connecting rod 2333, a feeding crank 2334, and a feeding motor 2335. One side of the tooth-changing base 2331 is hinged to the other end of the rack 2311 away from the lifter base 2321. The tooth-changing base 2331 is fixed on the tooth-changing bracket 2332. The crank end of the tooth-changing bracket 2332 is hinged to the feeding connecting rod 2333. The other end of the feeding connecting rod 2333 is hinged to the feeding crank 2334. The other end of the feeding crank 2334 away from the hinge is fixed on the motor shaft of the feeding motor 2335. By driving the feeding crank 2334 to rotate by the feeding motor 2335 and transmitting according to the hinge relationship, the rack 2311 is finally driven to swing.

[0091] The specific working process of this solution is as follows:

[0092] In this technical solution, the first driving member 41 drives the first transmission rod 51 to drive the first cutting knife 21 in the first moving knife assembly 2 to rotate around the axis. Similarly, the second driving member 42 drives the second cutting knife 31 to rotate around the same axis. During the starting sewing stage, the thread hole groove 6 is located directly below the sewing needle 200. The sewing needle 200 performs the downward needle action of the first needle: the sewing needle 200 penetrates downward through the fabric and the thread hole groove 6 and enters the rotary hook mechanism 100 to pick up the bobbin thread and then withdraws. The thread take-up lever picks up the thread upward and drives the top thread on the sewing needle 200 to retreat. The storage of the top thread is completed during the process of the thread take-up lever picking up the thread upward. The sewing thread end on the sewing needle 200 remains in the thread hole groove 6. The first cutting knife 21 rotates to clamp the thread end by the thread clamp 16, performs the thread locking for the second needle's downward needle, and drives the second cutting knife 31 to cooperate in cutting the thread. When in the finishing stage, the first driving member 41 drives the first cutting knife 21 to penetrate forward through the thread loop. The openings of the thread hooking groove 71 and the thread hooking groove 72 hook the top and bobbin threads, and then rotate to repeat the above thread cutting operation to ensure the accuracy and efficiency of thread cutting, reduce the thread residue, eliminate the subsequent manual processing steps, and improve the automation degree and production efficiency of the overall production process.

[0093] The above has shown and described the basic principles, main features and advantages of the present technical solution. Those skilled in the art should understand that the present technical solution is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present technical solution. Without departing from the spirit and scope of the present technical solution, the present technical solution will have various changes and improvements, and these changes and improvements all fall within the scope of the present technical solution claimed. The scope of protection required by the present technical solution is defined by the appended claims and their equivalents.

Claims

1. A double-acting knife thread-cutting sewing machine, comprising a frame (1), a thread-cutting mechanism and a rotary hook mechanism, wherein the thread-cutting mechanism is arranged on the frame (1) and is located below the sewing needle, and is characterized in that: It further includes a presser foot lifting mechanism (19) which is arranged on the frame (1), and a presser foot (20) for lifting and pressing the sewing material is arranged at the lower part of the presser foot (20) mechanism (19); a feeding mechanism (23) which is arranged on the frame (1) and is located below the presser foot (20) for feeding the sewing material forward; the thread cutting mechanism includes a first moving knife assembly (2), a second moving knife assembly (3) and a driving assembly (4), and the driving assembly (4) includes a first driving member (41) and a second driving member (42); both the first moving knife assembly (2) and the second moving knife assembly (3) are rotatably sleeved outside the matching rotating hook mechanism; the driving assembly (4) drives the first moving knife assembly (2) to rotate between a first position and a second position around the axis of the rotating hook mechanism, and drives the second moving knife assembly (3) to move between a third position and a fourth position around the axis of the rotating hook mechanism; the first moving knife assembly (2) includes a first moving knife holder (22) and a first thread cutting moving knife (21), the first moving knife holder (22) includes a first crank (221), a first connecting rod (222) and a first ring part (223), two ends of the first connecting rod (222) are respectively hinged to the first crank (221) and the first ring part (223), and the first thread cutting moving knife (21) is arranged on the first ring part (223); the first thread cutting moving knife (21) is provided with a thread hole groove (6) for the sewing needle to pass through and hook the sewing thread in the starting sewing stage and a first thread hooking groove (71) for hooking the sewing thread in the ending sewing stage, and a first cutting edge is further arranged on the front side of the first thread cutting moving knife; the second moving knife assembly (3) includes a second moving knife holder (32) and a second thread cutting moving knife (31), the second moving knife holder (32) includes a second crank (321), a second connecting rod (322) and a second ring part (323), two ends of the second connecting rod (322) are respectively hinged to the second crank (321) and the second ring part (323), and the second thread cutting moving knife (31) is arranged on the second ring part (323); a second cutting edge is arranged on the front side of the second thread cutting moving knife (31); during the rotation of the second thread cutting moving knife (31), it abuts against the surface of the first thread cutting moving knife (21), so that the first cutting edge of the first thread cutting moving knife (21) and the second cutting edge of the second thread cutting moving knife (31) cooperate to cut the sewing thread; a thread clamp (16) which is arranged on the frame (1), is located between the first position and the second position and is close to the second position; during the process of the first thread cutting moving knife (21) resetting to the second position, the first thread cutting moving knife (21) cooperates with the thread clamp (16) to clamp the sewing thread in the thread hole groove (6).

2. The double-acting knife thread-cutting sewing machine according to claim 1, characterized in that: the driving assembly (4) further includes a sleeve rod structure (5); the sleeve rod structure (5) includes a first transmission rod (51) and a second transmission rod (52) which is arranged inside the first transmission rod (51) or sleeved outside the first transmission rod (51); The first driving member (41) drives the first thread cutting moving knife (21) through a first transmission rod (51); the second driving member (42) drives the second thread cutting moving knife (31) through a second transmission rod (52).

3. The sewing machine with double-acting cutter for thread cutting according to claim 2, characterized in that: The first thread cutting moving knife (21) is further provided with a second thread hooking groove (72), and the second thread hooking groove (72) and the first thread hooking groove (71) are respectively located on both sides of the width of the first thread cutting moving knife (21); When performing thread cutting in the finishing stage, the first thread cutting moving knife (21) moves towards the direction of the sewing needle, and the tip of the first thread cutting moving knife (21) passes through the loop of the sewing thread; the first thread hooking groove (71) and the second thread hooking groove (72) respectively hook the sewing threads on both sides of the first thread cutting moving knife (21); A first wire guiding groove (181) is arranged between the wire hole groove (6) of the first thread cutting moving knife (21) and the first cutting edge, and the first thread hooking groove (71) is located in the middle of the first wire guiding groove (181).

4. The double-acting knife thread-cutting sewing machine according to claim 2, wherein: The thread cutting mechanism further includes a first transmission assembly (8), which includes a first crank arm (81) and a second crank arm (82) movably arranged on the first crank arm (81); The other end of the first crank arm (81) is connected to the drive shaft of the first driving member (41), and the end of the second crank arm (82) far from the first crank arm is fixed to the first transmission rod (51); A sliding groove (10) is arranged on the end face of the second crank arm (82) close to the first crank arm (81), and a sliding block (11) is correspondingly fixed at the swinging end of the first crank arm (81), and the sliding block (11) is arranged in the sliding groove (10) to realize sliding guiding; The second crank arm (82) is provided with a limiting portion (12), which is fixed at one end of the sliding groove (10) far from the fixed end of the second crank arm (82) to limit the sliding block (11) from falling off the sliding groove (10); The swinging of the first crank arm (81) drives the first transmission rod (51) to rotate, and the other end of the first transmission rod (51) directly or indirectly drives the first moving knife assembly (2).

5. The double-acting knife thread-cutting sewing machine according to claim 2, wherein: The thread cutting mechanism further includes a second transmission assembly (9), which includes a third crank arm (91) and a swinging cam (92) arranged on the third crank arm (91); One end of the third crank arm (91) is fixed on the drive shaft of the second driving member (42), and an adjusting portion (13) is arranged at the other swinging end of the third crank arm (91) close to the swinging cam (92), and the adjusting portion (13) acts on the swinging cam (92) so that the third crank arm (91) transmits power to the second transmission rod (52).

6. The double-acting knife thread-cutting sewing machine according to claim 2, wherein: The second transmission rod (52) is provided with an elastic member (14), which is sleeved on one end of the second transmission rod (52) provided with a second crank (321); The second crank (321) is provided with a connecting block (15), and the elastic member (14) is arranged between the connecting block (15) and the machine frame (1), and its elastic force is used for the reset of the second thread cutting moving knife (31).

7. The sewing machine with double-acting knife for thread cutting according to claim 5, characterized in that :Both ends of the second driving member (42) are provided with motor shafts, and the motor shafts include a first motor shaft (24) and a second motor shaft (25). The first motor shaft (24) drives the third crank (91), and the second motor shaft (25) at the other end drives the presser foot (20) to achieve stitch length adjustment.

8. The double-acting knife thread-cutting sewing machine according to claim 7, wherein: The presser foot mechanism (19) includes a driving cam (191), a connecting rod structure (192), and a press rod structure (193). The lower part of the connecting rod structure (192) acts on the driving cam (191); The other end of the connecting rod structure (192) acts on the press rod structure (193). The lower part of the press rod structure (193) is provided with the presser foot (20). The driving cam (191) is fixed to the second motor shaft (25), so that the second driving member (42) drives the presser foot (20) to operate.

9. The double-acting scissor-type thread trimming sewing machine according to claim 1, characterized in that: The feeding mechanism (23) includes: A feed dog assembly (231), which includes a dog frame (2311) and feed dogs (2312). The feed dogs (2312) are fixed on the dog frame (2311); A lifting dog assembly (232), which includes a lifting dog seat (2321) hinged to the dog frame (2311) and a shaft rod (2322) arranged on the lifting dog seat (2321). The shaft rod (2322) is rotatably installed on the machine frame, and the lifting dog seat (2321) drives the dog frame (2311) to move up and down; A tooth-changing assembly (233), which includes a tooth-changing seat (2331), a tooth-changing bracket (2332) arranged on the tooth-changing seat (2331), a feed link (2333), a feed crank (2334), and a feed motor (2335). The tooth-changing seat (2331) is hinged to the other end of the dog frame (2311) far from the lifting dog seat (2321); The crank end of the tooth-changing bracket (2332) is hinged to the end of the feed link (2333). The other end of the feed link (2333) is hinged to the end of the feed crank (2334). The other end of the feed crank (2334) is connected to the driving end of the feed motor (2335), so that the feed motor (2335) drives the feed crank (2334) to swing, for driving the dog frame (2311) to swing left and right.

10. The double-acting knife thread-cutting sewing machine according to any one of claims 1-9, characterized in that: The machine frame (1) is provided with a thread absorber (17). The discharge suction port of the thread absorber (17) is received at the thread hole groove (6), and it is used to suck the thread end after cutting.

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