CN221663174U - Sewing machine with dial line structure - Google Patents

Abstract

The utility model relates to a sewing machine with a thread-shifting structure. It is mainly used to solve the technical problems that the existing sewing devices have single functions, poor thread-shifting action stability, low flexibility and low reliability, which lead to single sewing tracks, poor integrity and low appearance. It includes a frame, a transmission mechanism, a needle plate and a hook, and also includes a swing mechanism and a fork mechanism. The fork mechanism includes a swing shaft, a rotating arm, a connecting block, a first support arm, a support arm seat, a support arm shaft, a second support arm, a guide limiter, a first thread-shifting needle and a second thread-shifting needle. The swing mechanism drives the swing shaft to swing back and forth along the frame, and the fork mechanism drives the first thread-shifting needle and the second thread-shifting needle. Through the fork mechanism, the sewing device can shift the thread through the thread-shifting needles on both sides before sewing. The thread-shifting mechanism has the advantages of good thread-shifting action stability, high flexibility and high reliability, so that the sewing track is rich, the integrity is strong and the appearance is high.

Description

A sewing machine with thread-pulling structure

Technical Field

The utility model relates to a sewing device, in particular to a sewing machine with a thread-pulling structure.

Background Art

As is known to all, a sewing machine is a machine that uses one or more sewing threads to form one or more stitches on the sewing material, so that one or more layers of sewing materials are interwoven or sewn together. Sewing machines can sew fabrics such as cotton, linen, silk, wool, and synthetic fibers, as well as products such as leather, plastic, and paper. The stitches are neat, beautiful, flat, and firm, and the sewing speed is fast and easy to use. Art forms such as hand-push embroidery and computer embroidery have been derived from it. When sewing, the existing sewing device has a relatively single stitch track due to the structural problem of the thread-shifting mechanism. It is generally difficult to sew a triangular thread track. In addition, the thread-shifting structure also has the technical problem of poor thread-shifting stability, poor thread-shifting positioning effect, and poor reliability, which leads to poor integrity of the sewn thread track and an unsightly appearance. Moreover, when sewing, the hook thread is easily cut off by the hook, which greatly affects the sewing.

Utility Model Content

In order to overcome the shortcomings and deficiencies of the background technology, the utility model provides a sewing machine with a thread-shifting structure, which solves the technical problems that the existing sewing device has a single function and is limited by the thread-shifting structure, resulting in poor thread-shifting action stability, low flexibility and low reliability, thereby leading to a single sewing trajectory, poor integrity and low appearance.

The technical solution of the utility model is: a sewing machine with a thread shifting structure, including a frame, a transmission mechanism, a needle plate and a hook needle, and also including a swing mechanism and a fork mechanism. The fork mechanism includes a swing shaft, a rotating arm, a connecting block, a first support arm, a support arm seat, a support arm shaft, a second support arm, a guide limiter, a first thread shifting needle and a second thread shifting needle. The swing mechanism drives the swing shaft to swing back and forth along the frame, one end of the rotating arm is fixedly connected to the swing shaft, and the other end is hinged to the upper end of the first support arm through the connecting block. The support arm seat is movably sleeved on the first support arm, and the support arm shaft can be rotatably arranged on the frame and linked to the support arm seat. The lower ends of the two support arms are connected to the lower end of the first support arm, and the upper end of the second support arm is provided with a guide slot, and the guide limit piece passes through the guide slot and is fixedly connected to the support arm seat. The first thread shifting needle is connected to the left side of the lower end of the first support arm, and the second thread shifting needle is connected to the right side of the lower end of the second support arm. The rotation of the swing shaft drives the rotating arm to rotate, driving the first support arm to move downward and driving the second support arm to move downward. At the same time, the support arm seat rotates toward the outer side and downward along the axis of the support arm shaft and slides with the guide slot on the second support arm to cooperate with the guide limit piece, so that the first thread shifting needle and the second thread shifting needle move downward and shift the crochet thread to both sides.

The swing mechanism includes a rotating shaft, an eccentric wheel, a positioning pin, a slider, a swing arm, a gear ring and a gear. The eccentric wheel is eccentrically arranged on the rotating shaft, the positioning pin is eccentrically connected to the eccentric wheel, the swing arm is hinged to the frame, a linear slide rail is arranged at the upper end of the swing arm, the slider is sleeved on the positioning pin and slidably cooperates with the linear slide rail, the gear ring is arranged at the lower end of the swing arm, the gear is meshed with the gear ring, and the swing shaft is fixedly connected to the gear.

The first support arm includes a lifting rod portion and a mounting seat portion, the mounting seat portion is located at the lower end of the lifting rod portion, the second support arm is connected to the mounting seat portion through a pin, the support arm seat is movably mounted on the lifting rod portion, the first thread shifting needle is fixed on the mounting seat, and the second thread shifting needle is fixed to the mounting portion through the second support arm.

The support arm shaft is a hollow shaft, a positioning shaft is provided on the frame, the support arm shaft is sleeved outside the positioning shaft, a transmission disk is fixed to the end of the support arm shaft, a linkage disk is connected to the support arm seat, a slot is provided on the linkage disk, a limit pin which is inserted into the slot is provided on the transmission disk, and the support arm seat drives the support arm shaft to rotate along the positioning shaft through the linkage disk and the transmission disk.

Limiting baffles are arranged on both sides of the sliding block, and the limiting baffles are engaged with the surface of the swing arm.

It also includes an articulated shaft, which is connected to the rotating arm. The upper end of the connecting block is hinged to the articulated shaft. The lower end of the connecting block is provided with an insertion port. The upper end of the first support arm is inserted into the insertion port and fixedly connected to the connecting block.

The transmission mechanism comprises a main shaft, a main gear and a transmission gear. The main shaft is in transmission cooperation with the main gear, the transmission gear is meshed with the main gear, and the transmission gear is in cooperation with the rotating shaft.

The needle plate is provided with a sewing opening, and the needle plate is provided with a first groove and a second groove which cooperate with the first thread shifting needle and the second thread shifting needle. A wire groove is provided between the first groove and the second groove, one end of the wire groove is connected with the first groove, and the other end of the wire groove is connected with the second groove. The fork mechanism drives the first thread shifting needle and the second thread shifting needle to move downward close to the needle plate and shift the sewing thread on the crochet hook, and the first thread shifting needle is inserted into the first groove, and the second thread shifting needle is inserted into the second groove.

The present invention relates to a material ejection device provided on a frame, wherein the material ejection device comprises a material ejection transmission mechanism, a rotating shaft, a ejection rod seat and an ejection rod, wherein the ejection rod is arranged on the ejection rod seat, and the transmission mechanism drives the rotating shaft to rotate, and further comprises a rotating frame and a lifting rotating arm, wherein the rotating frame is fixedly connected to the rotating shaft, a positioning pin is provided at the upper end of the rotating frame, the upper end of the lifting rotating arm is hinged with the ejection rod seat, and the lower end is sleeved on the positioning pin, and the material ejection transmission mechanism comprises a transmission shaft (11), an eccentric wheel, an eccentric connecting rod, a first rotating arm, a movable block, a push-pull connecting rod, a connecting block, a clamping shaft block, a second rotating arm, an eccentric shaft, a rotating wheel, and an operating component. The eccentric wheel is arranged on the transmission shaft, the upper end of the eccentric connecting rod is matched with the eccentric wheel transmission, and the lower end is hinged to the movable block, one end of the first rotating arm is hinged to the frame, and the other end is hinged to the movable block, the movable block is hinged to the push-pull connecting rod, the push-pull connecting rod is hinged to one end of the connecting block, the other end of the connecting block is hinged to the clamping shaft block, the clamping shaft block is fixedly connected to the rotating shaft, the eccentric shaft is arranged on the rotating wheel, the eccentric shaft is hinged to one end of the second rotating arm, the other end of the second rotating arm is hinged to the movable block (15), and the second rotating arm is located below the first rotating arm.

It also includes an adjusting mechanism, which includes a pushing assembly, a rotating sleeve, a positioning shaft, a pushing shaft sleeve and an adjusting rotating block. The positioning shaft is fixed to the frame, the rotating sleeve is hinged to the positioning shaft, the pushing assembly drives the rotating sleeve to rotate along the positioning shaft, the pushing shaft sleeve is arranged outside the rotating shaft, the adjusting rotating block is hinged to the rotating frame, one end of the pushing shaft sleeve is in contact with the rotating sleeve, and the other end is in contact with the adjusting rotating block, one end of the adjusting rotating block cooperates with the pushing shaft sleeve, and the other end abuts against the positioning pin shaft.

The rotating frame includes a positioning seat and a lifting slider. The positioning seat is fixedly connected to the rotating shaft. The lifting slider can slide up and down along the positioning seat. The lifting slider is provided with a through groove whose length is greater than the outer diameter of the rotating shaft. The rotating shaft passes through the through groove. The push sleeve pushes the adjusting rotating block to drive the lifting slider to slide upward.

The utility model has the following beneficial effects: the sewing device can, through the fork mechanism, shift the thread by the thread shifting needles on both sides and then sew; the thread shifting mechanism has the advantages of good thread shifting action stability, high flexibility and strong reliability, thereby achieving the technical problem of rich sewing tracks, strong integrity and high appearance aesthetics.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of the utility model.

FIG. 2 is a structural state diagram of the shift fork mechanism in the utility model.

FIG. 3 is a schematic structural diagram of the fork mechanism in the utility model from another angle.

FIG4 is an enlarged view of a local structure of the present utility model.

FIG. 5 is a schematic structural diagram of the needle plate of the utility model.

FIG. 6 is a schematic diagram of the internal structure of the utility model.

FIG. 7 is a schematic diagram of the internal structure of the present invention from another angle.

FIG8 is a schematic structural diagram of the ejection mechanism in the utility model.

FIG. 9 is a schematic diagram of the internal structure of the ejection mechanism in the present utility model.

In the figure, the frame 1, the needle plate 2, the hook 3, the swing shaft 4, the rotating arm 5, the connecting block 6, the first arm 7, the arm seat 8, the arm shaft 9, the second arm 10, the guide limiter 11, the first thread needle 12, the second thread needle 13, the guide slide 14, the rotating shaft 15, the eccentric wheel 16, the positioning pin 17, the slider 18, the swing arm 19, the gear ring 20, the gear 21, the linear slide 22, the pin 23, the positioning shaft 24, the transmission plate 25, the linkage plate 26, the slot 27, the limit pin 28, the limit baffle 29, the hinge shaft 30, the plug interface 31, the main shaft 32, Main gear 33, transmission gear 34, sewing mouth 35, first groove 36, second groove 37, wire groove 38, ejector shaft 39, ejector rod seat 40, ejector rod 41, rotating frame 42, lifting and lowering rotating arm 43, positioning pin shaft 44, ejector eccentric wheel 45, eccentric connecting rod 46, first rotating arm 47, movable block 48, push-pull connecting rod 49, rotating connecting piece 50, clamping shaft block 51, second rotating arm 52, ejector eccentric shaft 53, rotating wheel 54, adjusting ejector rod 55, rotating sleeve 56, adjusting positioning shaft 57, ejector sleeve 58, adjusting rotating block 59, through groove 60.

DETAILED DESCRIPTION

The following is further described with respect to the embodiments of the present invention:

As shown in the figure, a sewing machine with a thread shifting structure includes a frame 1, a transmission mechanism, a needle plate 2 and a hook needle 3, and also includes a swing mechanism and a fork mechanism. The fork mechanism includes a swing shaft 4, a rotating arm 5, a connecting block 6, a first support arm 7, a support arm seat 8, a support arm shaft 9, a second support arm 10, a guide limiter 11, a first thread shifting needle 12 and a second thread shifting needle 13. The swing mechanism drives the swing shaft 4 to swing back and forth along the frame 1. One end of the rotating arm 5 is fixedly connected to the swing shaft 4, and the other end is hinged to the upper end of the first support arm 7 through the connecting block 6. The support arm seat 8 is movably sleeved on the first support arm 7. The support arm shaft 9 can be rotatably arranged on the frame 1 and linked to the support arm seat 8. The lower end of the second support arm 10 is connected to the support arm seat 8. The lower end of the first support arm 7 is connected, and the upper end of the second support arm 10 is provided with a guide slot 14. The guide limiter 11 passes through the guide slot 14 and is fixedly connected to the support arm seat 8. The first thread shifting needle 12 is connected to the left side of the lower end of the first support arm 7, and the second thread shifting needle 13 is connected to the right side of the lower end of the second support arm 10. The rotation of the swing shaft 4 drives the rotating arm 5 to rotate and drives the first support arm 7 to move downward, driving the second support arm 10 to move downward. At the same time, the support arm seat 8 rotates toward the outside and downward along the axis of the support arm shaft 9 and slides with the guide slot 14 on the second support arm 10 and cooperates with the guide limiter 11, so that the first thread shifting needle 12 and the second thread shifting needle 13 move downward and shift the crochet thread to both sides. The shift fork mechanism is composed of a swing shaft, a rotating arm, a connecting block, a first support arm, a support arm seat, a support arm shaft, a second support arm and a guide limiter. During sewing, the swing shaft swings to drive the rotating arm to rotate, and the rotating arm drives the first support arm to move downward through the connecting block. Since the rotation of the rotating arm can drive the first support arm to move outward and downward, the support arm seat will be driven to rotate outward and move downward along the support arm shaft. Since the first thread shifting needle is installed on the first support arm, the first thread shifting needle moves downward and shifts to the left side under the drive of the first support arm, and the second thread shifting needle is installed on the second support arm, and the lower end of the second arm is It is hingedly installed on the first arm, and the upper end is connected to the surface of the arm seat through a guide limiter. In combination with the cooperation of the guide slot and the guide limiter, the first arm moves downward and drives the second thread-shifting needle to move downward. In combination with the rotation of the arm seat, the second arm rotates to the right under the cooperation of the guide limiter and the guide slot, driving the second thread-shifting needle to shift the hook thread to the right. Since the sewing thread first passes through the hook needle and bypasses the first thread-shifting needle and the second thread-shifting needle and then comes back, when sewing, the first thread-shifting needle and the second thread-shifting needle shift the thread on the left and right sides to form a triangle, which can realize a triangular thread trajectory. According to the above scheme, the sewing device can shift the thread through the thread-shifting needles on both sides and then sew through the fork mechanism. The thread-shifting mechanism has the advantages of good thread-shifting action stability, high flexibility and high reliability, thereby achieving the technical problems of rich sewing trajectories, strong integrity and high appearance.

In the utility model, as shown in the figure, the swing mechanism includes a rotating shaft 15, an eccentric wheel 16, a positioning pin 17, a slider 18, a swing arm 19, a ring gear 20 and a gear 21. The eccentric wheel 16 is eccentrically arranged on the rotating shaft 15, the positioning pin 17 is eccentrically connected to the eccentric wheel 16, the swing arm 19 is hinged to the frame 1, and a linear slide rail 22 is provided at the upper end of the swing arm 19. The slider 18 is sleeved on the positioning pin 17 and slidably cooperates with the linear slide rail 22. The ring gear 20 is arranged at the lower end of the swing arm 19, the gear 21 is meshed with the ring gear 20, and the swing shaft 4 is fixedly connected to the gear 21. The rotation of the rotating shaft 15 drives the eccentric wheel 16 to rotate. The positioning pin 17 is eccentrically connected to the eccentric wheel 16. Since a slider 18 is provided outside the positioning pin, when the rotating shaft rotates, the positioning pin 17 drives the slider to slide up and down in the linear slide rail 22, and drives the swing arm 19 to swing left and right at the same time. The above-mentioned swing mechanism has the advantages of compact structure, strong action stability, high reliability and good performance.

In the present invention, as shown in the figure, the first support arm 7 includes a lifting rod portion 71 and a mounting seat portion 72, the mounting seat portion 72 is located at the lower end of the lifting rod portion 71, the second support arm 10 is connected to the mounting seat portion 72 through a pin 23, the support arm seat 8 is movably sleeved on the lifting rod portion 71, the first thread shifting needle 12 is connected to one side of the mounting seat portion 72, and the second thread shifting needle 13 is connected to the other side of the mounting seat portion 72 through the first support arm 10. The above structure makes the installation structure of the first support arm, the first support arm and the first thread shifting needle and the second thread shifting needle more reasonable and reliable, and effectively improves the movement stability and flexibility of the needle and thread shifting.

In the present utility model, as shown in the figure, the arm shaft 9 is a hollow shaft, the frame 1 is provided with a positioning shaft 24, the arm shaft 9 is sleeved outside the positioning shaft 24, a transmission disc 25 is fixed to the end of the arm shaft 9, a linkage disc 26 is connected to the arm seat 8, a slot 27 is provided on the linkage disc 26, a limit pin 28 is provided on the transmission disc 25 that is inserted into the slot 27, and the arm seat 8 drives the arm shaft 9 to rotate along the positioning shaft 24 through the linkage disc 26 and the transmission disc 25. With the above structure, the arm seat and the arm shaft are transmitted through the cooperation of the transmission disc and the linkage disc, and the arm shaft is hollow and sleeved on the positioning shaft, so that the arm seat has strong linkage when rotating along the arm shaft, high reliability, and effectively improves the performance of the equipment.

In the present utility model, as shown in the figure, the two sides of the slider 18 are provided with limit baffles 29, and the limit baffles 29 are engaged with the surface of the swing arm 19, and also include a hinge shaft 30, the hinge shaft 30 is connected to the rotating arm 5, the upper end of the connecting block 6 is hinged to the hinge shaft 30, the lower end of the connecting block 6 is provided with an insertion port 31, the upper end of the first arm 7 is inserted into the insertion port 31 and fixedly connected to the connecting block 6. The limit baffle is provided so that the slider plays a role of limiting, and the first arm is connected to the connecting block through the insertion port, which is convenient and reliable.

In the present utility model, as shown in the figure, the transmission mechanism includes a main shaft 32, a main gear 33 and a transmission gear 34, the main shaft 32 and the main gear 33 are in transmission cooperation, the transmission gear 34 is meshed with the main gear 33, and the transmission gear 34 is matched with the rotating shaft 15. The main shaft 32 drives the transmission gear 34 to rotate through the main gear 33, and the transmission gear 34 drives the rotating shaft 15 to rotate, and the transmission is stable and reliable.

In the present utility model, as shown in the figure, the needle plate 2 is provided with a sewing opening 35, and the needle plate 2 is provided with a first groove 36 and a second groove 37 that match the first thread shifting needle 12 and the second thread shifting needle 13. A thread groove 38 is provided between the first groove 36 and the second groove 37, and one end of the thread groove 38 is connected to the first groove 36, and the other end of the thread groove 38 is connected to the second groove 37. The fork mechanism drives the first thread shifting needle 12 and the second thread shifting needle 13 to move downward close to the needle plate 2 and shift the sewing thread on the hook needle 3, and the first thread shifting needle 12 is inserted into the first groove 36, and the second thread shifting needle 13 is inserted into the second groove 37. By arranging an embedded structure on the needle plate, when sewing, the thread shifting needles shift the sewing thread through the first thread shifting needle and the second thread shifting needle and sink into the first groove and the second groove, and then sew through the hook needle to prevent the sewing thread from being cut, effectively realizing the safety and reliability of the sewing process, and the overall structure is reasonable and reliable, which effectively improves production efficiency and economic benefits.

In the present utility model, as shown in the figure, the frame is provided with a material ejecting device, and the material ejecting device includes a material ejecting transmission mechanism, a material ejecting shaft 39, a rod seat 40 and a rod 41, the rod 41 is arranged on the rod seat 40, the transmission mechanism drives the material ejecting shaft 39 to rotate, and also includes a rotating frame 42 and a lifting arm 43, the rotating frame 42 is fixedly connected to the material ejecting shaft 39, the upper end of the rotating frame 42 is provided with a positioning pin 44, the upper end of the lifting arm 43 is hinged to the rod seat 40, and the lower end is sleeved on the positioning pin 44, the material ejecting transmission mechanism includes a material ejecting eccentric wheel 45, an eccentric connecting rod 46, a first rotating arm 47, a movable block 48, a push-pull connecting rod 49, a rotating connector 50, a clamping shaft block 51 and a second rotating arm 52, a material ejecting eccentric shaft 53, a rotating wheel 5 4. The ejection eccentric wheel 45 is arranged on the main shaft 32, the upper end of the eccentric connecting rod 46 is in transmission cooperation with the ejection eccentric wheel 45, and the lower end is hinged to the movable block 48, one end of the first rotating arm 47 is hinged to the frame 1, and the other end is hinged to the movable block 48, the movable block 48 is hinged to the push-pull connecting rod 49, the push-pull connecting rod 49 is hinged to one end of the rotating connecting member 50, the other end of the rotating connecting member 50 is hinged to the clamping shaft block 51, the clamping shaft block 51 is fixedly connected to the ejection rotating shaft 39, the ejection eccentric shaft 53 is arranged on the rotating wheel, the ejection eccentric shaft 53 is hinged to one end of the second rotating arm 52, the other end of the second rotating arm 52 is hinged to the movable block 48, and the second rotating arm 52 is located below the first rotating arm 47. The transmission mechanism is composed of a transmission shaft, an eccentric wheel, an eccentric connecting rod, a first rotating arm, a movable block, a push-pull connecting rod, a connecting block, a clamping shaft block, a second rotating arm, an eccentric shaft, a rotating wheel, and an operating component. When in use, the transmission shaft drives the eccentric wheel to rotate, and the eccentric wheel drives the movable block through the eccentric connecting rod. The first rotating arm rotates, and the movable block presses down to drive the connecting block to rotate through the push-pull connecting rod. The connecting block presses down to drive the rotating shaft to rotate through the clamping shaft block. The rotating frame is fixedly connected to the rotating shaft. The upper end of the rotating frame 8 is provided with a positioning pin shaft 10. The upper end of the lifting rotating arm is hinged with the pushing rod seat, and the lower end is sleeved on the positioning pin shaft 10. The rotation of the rotating shaft drives the lower end of the lifting arm to rotate through the rotating frame to realize the lifting of the material. When switching, the eccentric shaft is driven to rotate through the operating component to drive the second rotating arm to move, and the second rotating arm drives the sliding block to move to drive the push-pull connecting rod to move, and the rotating shaft is driven to rotate through the connecting block and the clamping shaft block to realize switching. The height of the push rod on the push rod seat can be adjusted through the transmission mechanism combined with the rotating frame and the lifting arm, so that the height of the push rod can be effectively adjusted. According to the thickness of the cloth, the height required for the push rod to push the material can be switched. It is easy to switch, has strong adjustment function, wide range of use and easy operation.

In the utility model, as shown in the figure, it also includes an adjustment mechanism, which includes an adjustment push rod 55, a rotating sleeve 56, an adjustment positioning shaft 57, a push sleeve 58 and an adjustment rotating block 59. The adjustment positioning shaft 57 is fixed to the frame 1, and the rotating sleeve 56 is hinged to the adjustment positioning shaft 57. The adjustment push rod 55 drives the rotating sleeve 56 to rotate along the adjustment positioning shaft 57. The push sleeve 58 is arranged outside the ejection rotating shaft 39, and the adjustment rotating block 59 is hinged to the rotating frame 42. One end of the push sleeve 58 contacts the rotating sleeve 56, and the other end contacts the adjustment rotating block 59. One end of the adjustment rotating block 59 cooperates with the push sleeve 58, and the other end abuts against the positioning pin shaft 44. When in use, the push rod can drive the rotating sleeve to rotate to promote the axial movement of the push shaft sleeve, thereby pushing the adjusting rotating block to rotate around the rotating frame, and the positioning pin shaft can be used to drive the lifting arm to move to adjust the height of the push rod on the push rod seat, thereby realizing fine adjustment of the push rod. The above structure has the advantages of high adjustment accuracy, strong controllability, and high movement flexibility.

In the present utility model, as shown in the figure, the rotating frame 42 includes a positioning seat 421 and a lifting slider 422. The positioning seat 421 is fixedly connected to the ejection shaft 39. The lifting slider 422 can slide up and down along the positioning seat 421. The lifting slider 422 is provided with a through slot 60 whose length is greater than the outer diameter of the ejection shaft 39. The ejection shaft 39 passes through the through slot 60. The push sleeve 59 pushes the adjustment block 59 to drive the lifting slider 422 to slide. When the ejection shaft rotates, the rotating frame will be driven to rotate, and the positioning seat and the lifting slider will rotate together, driving the lifting arm to rotate to achieve the height adjustment of the ejector. When fine-tuning, the push sleeve presses the adjustment block to rotate and pushes the positioning pin to drive the lifting slider to move upward to achieve the fine adjustment of the ejector. At this time, the lifting slider slides upward relative to the positioning seat. The rotating frame adopting the above structure can realize the height switching and fine-tuning of the ejector, with reasonable structure, wide adjustment range, good use effect and rich functions.

Claims (10)

1. A sewing machine with a thread shifting structure, comprising a frame (1), a transmission mechanism, a needle plate (2) and a hook needle (3), characterized in that it also includes a swing mechanism and a fork mechanism, the fork mechanism comprising a swing shaft (4), a rotating arm (5), a connecting block (6), a first support arm (7), a support arm seat (8), a support arm shaft (9), a second support arm (10), a guide stopper (11), a first thread shifting needle (12) and a second thread shifting needle (13), the swing mechanism drives the swing shaft (4) to rotate, and the fork mechanism drives the swing shaft (4) to rotate. ) swings back and forth along the frame (1), one end of the swing arm (5) is fixedly connected to the swing shaft (4), and the other end is connected to the hinge shaft (30), which is hinged to the hinge shaft (30) through the upper end of the connecting block (6), the upper end of the connecting block (6) is hinged to the hinge shaft (30), the lower end of the connecting block (6) is fixedly connected to the upper end of the first support arm (7), the support arm seat (8) is movably sleeved on the first support arm (7), and the support arm shaft (9) is rotatably arranged The second support arm (10) is on the frame (1) and is linked to the support arm seat (8); the lower end of the second support arm (10) is connected to the lower end of the first support arm (7); the upper end of the second support arm (10) is provided with a guide slot (14); the guide limiter (11) passes through the guide slot (14) and is fixedly connected to the support arm seat (8); the first thread shifting needle (12) is connected to the left side of the lower end of the first support arm (7); the second thread shifting needle (13) is connected to the second support arm ( On the right side of the lower end of the support arm (10), the swing shaft (4) rotates to drive the rotating arm (5) to rotate and drive the first support arm (7) to move downward, driving the second support arm (10) to move downward. At the same time, the support arm seat (8) rotates toward the outside and downward along the axis of the support arm shaft (9) and slides with the guide limiter (11) through the guide groove (14) on the second support arm (10), thereby forming the first thread shifting needle (12) and the second thread shifting needle (13) to move downward and shift the hook thread to both sides. 2. A sewing machine with a thread-shifting structure according to claim 1, characterized in that: the swing mechanism comprises a rotating shaft (15), an eccentric wheel (16), a positioning pin (17), a slider (18), a swing arm (19), a gear ring (20) and a gear (21), the eccentric wheel (16) is eccentrically arranged on the rotating shaft (15), the positioning pin (17) is eccentrically connected to the eccentric wheel (16), the swing arm (19) is hinged to the frame (1), a linear slide rail (22) is provided at the upper end of the swing arm (19), the slider (18) is sleeved on the positioning pin (17) and slidably cooperates with the linear slide rail (22), the gear ring (20) is arranged at the lower end of the swing arm (19), the gear (21) is meshed with the gear ring (20), and the swing shaft (4) is fixedly connected to the gear (21). 3. A sewing machine with a thread shifting structure according to claim 1, characterized in that: the first support arm (7) includes a lifting rod portion (71) and a mounting seat portion (72), the mounting seat portion (72) is located at the lower end of the lifting rod portion (71), the second support arm (10) is connected to the mounting seat portion (72) through a pin (23), the support arm seat (8) is movably mounted on the lifting rod portion (71), the first thread shifting needle (12) is connected to one side of the mounting seat portion (72), and the second thread shifting needle (13) is connected to the other side of the mounting seat portion (72) through the second support arm (10). 4. A sewing machine with a thread-pulling structure according to claim 1, characterized in that: the support arm shaft (9) is a hollow shaft, a positioning shaft (24) is provided on the frame (1), the support arm shaft (9) is sleeved outside the positioning shaft (24), a transmission disk (25) is fixed to the end of the support arm shaft (9), a linkage disk (26) is connected to the support arm seat (8), a slot (27) is provided on the linkage disk (26), a limit pin (28) is provided on the transmission disk (25) which is inserted into the slot (27), and the support arm seat (8) drives the support arm shaft (9) to rotate along the positioning shaft (24) through the linkage disk (26) and the transmission disk (25). 5. A sewing machine with a thread-diverting structure according to claim 2, characterized in that: limit baffles (29) are provided on both sides of the slider (18), and the limit baffles (29) are engaged with the surface of the swing arm (19); a plug-in interface (31) is provided at the lower end of the connecting block (6), and the upper end of the first support arm (7) is inserted into the plug-in interface (31) and fixedly connected to the connecting block (6). 6. A sewing machine with a thread-shifting structure according to claim 2, characterized in that: the transmission mechanism includes a main shaft (32), a main gear (33) and a transmission gear (34), the main shaft (32) and the main gear (33) are in transmission cooperation, the transmission gear (34) is meshed with the main gear (33), and the transmission gear (34) is matched with the rotating shaft (15). 7. A sewing machine with a thread shifting structure according to claim 1 or 2 or 3 or 4 or 5, characterized in that: a sewing opening (35) is provided on the needle plate (2), and a first groove (36) and a second groove (37) are provided on the needle plate (2) to cooperate with the first thread shifting needle (12) and the second thread shifting needle (13), and a thread groove (38) is provided between the first groove (36) and the second groove (37), one end of the thread groove (38) is connected to the first groove (36), and the other end of the thread groove (38) is connected to the second groove (37), and the fork mechanism drives the first thread shifting needle (12) and the second thread shifting needle (13) to move downward close to the needle plate (2) and shift the sewing thread on the hook needle (3), and the first thread shifting needle (12) is inserted into the first groove (36), and the second thread shifting needle (13) is inserted into the second groove (37). 8. A sewing machine with a thread-pulling structure according to claim 6, characterized in that: a material-pushing device is provided on the frame, the material-pushing device comprises a material-pushing transmission mechanism, a material-pushing rotating shaft (39), a push rod seat (40) and a push rod (41), the push rod (41) is arranged on the push rod seat (40), the transmission mechanism drives the material-pushing rotating shaft (39) to rotate, and further comprises a rotating frame (42) and a lifting rotating arm (43), the rotating frame (42) is fixedly connected to the material-pushing rotating shaft (39), and the lifting rotating arm (43) is fixedly connected to the lifting rotating shaft (39). The material rotating shaft (39) is provided with a positioning pin shaft (44) at the upper end of the rotating frame (42); the upper end of the lifting rotating arm (43) is hinged with the ejector seat (40), and the lower end is sleeved on the positioning pin shaft (44); the ejector transmission mechanism comprises an ejector eccentric wheel (45), an eccentric connecting rod (46), a first rotating arm (47), a movable block (48), a push-pull connecting rod (49), a rotating connecting piece (50), a clamping shaft block (51), a second rotating arm (52), ... first rotating arm (47), a first rotating arm (47), a first rotating arm (47), a first rotating arm (47), a first rotating arm (47), a first rotating arm ( The main shaft (53) and the rotating wheel (54) are provided with the ejecting eccentric wheel (45) on the main shaft (32). The upper end of the eccentric connecting rod (46) is in driving cooperation with the ejecting eccentric wheel (45), and the lower end is hinged to the movable block (48). One end of the first rotating arm (47) is hinged to the frame (1), and the other end is hinged to the movable block (48). The movable block (48) is hinged to the push-pull connecting rod (49), and the push-pull connecting rod (49) is hinged to the rotating connecting member ( The second rotating arm (52) is hinged to one end of the second rotating arm (52), the other end of the rotating connecting member (50) is hinged to the clamping shaft block (51), the clamping shaft block (51) is fixedly connected to the ejecting rotating shaft (39), the ejecting eccentric shaft (53) is arranged on the rotating wheel, the ejecting eccentric shaft (53) is hinged to one end of the second rotating arm (52), the other end of the second rotating arm (52) is hinged to the movable block (48), and the second rotating arm (52) is located below the first rotating arm (47). 9. A sewing machine with a thread-pulling structure according to claim 8, characterized in that it also includes an adjusting mechanism, wherein the adjusting mechanism includes an adjusting push rod (55), a rotating sleeve (56), an adjusting positioning shaft (57), a pushing sleeve (58) and an adjusting rotating block (59), wherein the adjusting positioning shaft (57) is fixed to the frame (1), the rotating sleeve (56) is hinged to the adjusting positioning shaft (57), the adjusting push rod (55) drives the rotating sleeve (56) to rotate along the adjusting positioning shaft (57), the pushing sleeve (58) is arranged outside the ejecting rotating shaft (39), the adjusting rotating block (59) is hinged to the rotating frame (42), one end of the pushing sleeve (58) contacts with the rotating sleeve (56), and the other end contacts with the adjusting rotating block (59), one end of the adjusting rotating block (59) cooperates with the pushing sleeve (58), and the other end abuts against the positioning pin shaft (44). 10. A sewing machine with a thread-shifting structure according to claim 9, characterized in that: the rotating frame (42) includes a positioning seat (421) and a lifting slider (422), the positioning seat (421) is fixedly connected to the ejecting shaft (39), the lifting slider (422) can slide up and down along the positioning seat (421), the lifting slider (422) is provided with a through groove (61) whose length is greater than the outer diameter of the ejecting shaft (39), the ejecting shaft (39) passes through the through groove (61), and the pushing sleeve (58) pushes the adjusting rotating block (59) to drive the lifting slider (422) to slide.