A special trajectory cam needle bar stroke thread take-up device and method

Abstract

The present application relates to a special trajectory cam needle bar stroke thread picking device and method, the operation needle bar crank rotation drives the needle bar stroke cam to move along the stroke trajectory through the upper cam bearing, to match the synchronous movement of the needle bar and the balance to complete the hooking thread and the take-up and pay-off thread; in the process of the balance pay-off thread, the needle bar is driven to descend to complete the hooking thread in cooperation with the rotation of the swing shuttle, the needle bar is driven to lift to start the take-up thread in the rotation process of the swing shuttle completing the hooking thread, the needle bar is driven to ascend and descend to complete the take-up thread in the process of the balance take-up thread in cooperation with the rotation of the swing shuttle, and then the thread with stronger stability is realized, and the matching synchronization reliability and stability of the needle bar stroke are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewing equipment technical field, especially to a special trajectory cam needle bar stroke thread picking device and method, which is suitable for shuttle, lock stitch sewing machine and chain stitch sewing machine. BACKGROUND

[0002] The needle bar stroke thread picking device is the most important part of the sewing machine, and the reliability and stability of its structure determine the stability and coordination of feeding and take-up. Once the coordination is out of sync, the sewing cannot be realized or the stitches will be messy. At present, most of the needle bar stroke thread picking devices adopt a connecting rod structure. For example, the Chinese utility model patent with publication number CN203333985U discloses a connecting rod type balance set, which belongs to the field of sewing machines and comprises a needle bar crank, a thread picking crank, a needle bar connecting rod and a balance. One end of the thread picking crank is fixedly connected to the eccentric position of the needle bar crank. The other end of the thread picking crank is provided with an upper handle and a side handle. One end of the needle bar connecting rod is hingedly connected to the end of the side handle of the thread picking crank, and the balance is fixed to the end of the upper handle of the thread picking crank, so that the needle bar connecting rod and the balance are both located at the eccentric position of the thread picking crank, and the circular motion is converted into linear motion. Another example is the Chinese invention patent with publication number CN101333735B, which discloses a needle picking and thread hooking combined device of a sewing machine. The device comprises a shuttle swinging mechanism and a needle picking mechanism. The shuttle swinging mechanism is composed of a thread hooking crank assembly A and a swing shaft assembly B. The needle picking mechanism is composed of a needle bar cam assembly A and a swing lever assembly B. The thread hooking crank assembly A comprises a vertical shaft, a thread hooking crank, a long connecting rod, a shuttle bed swinging sector gear, a pinion, an upper shaft gear and a vertical shaft gear. The swing shaft assembly B comprises a mounting seat and a swing shaft which is threaded into the center seat sleeve of the mounting seat. The needle bar cam assembly A is composed of an upper shaft which is connected to the driving device of the main machine of the sewing machine and a needle bar cam which is sleeved on the shaft rod. The swing lever assembly B is composed of a needle bar, a swing lever, a needle bar swing lever and a fixing seat. The swinging motion mechanism of the shuttle of the sewing machine and the cam swing lever sliding block needle picking mechanism are simultaneously driven by the rotation of the upper shaft to realize the predetermined coordinated motion, thereby forming a new type of needle picking and thread hooking combined mechanism of the shuttle sewing machine. With the increasing requirements for production efficiency and stitches, the connecting rod type balance set cannot meet the requirements of stitch stability and stroke coordination synchronization. Therefore, the existing needle bar stroke thread picking device needs to be improved, and the focus is on the conversion structure from circular motion to linear motion. SUMMARY

[0003] The present application aims to solve the problems of the stroke coordination synchronization stability and stitch stability of the existing needle bar stroke thread picking device, and provides a special trajectory cam needle bar stroke thread picking device and method.

[0004] In a first aspect, the embodiments of the present application provide a special trajectory cam needle bar stroke thread lifting device, comprising a machine base, wherein the machine base is provided with a needle bar, a balance, a needle bar stroke cam slide plate, a needle bar stroke cam, a needle bar crank and a shuttle, the center shaft of the needle bar crank is used as a coaxial input end of external power, the needle bar crank is provided with an upper cam bearing, the needle bar stroke cam slide plate is assembled on the needle bar stroke cam, one end of the balance is pivotally connected to a thread lifting stroke adjusting seat of the machine base, the balance is provided with an elongated guide hole, the needle bar stroke cam slide plate is provided with a cam bearing movably inserted into the guide hole, and the needle bar is assembled on the needle bar stroke cam slide plate through a needle bar connecting rod.

[0005] In some embodiments, the upper cam bearing moves to the first position, the lowest position and the fourth position, and the needle bar is at the same horizontal height; when the upper cam bearing moves to the second position and the third position, the relative horizontal height of the needle bar is lowered; in the process that the upper cam bearing moves from the first position to the lowest position through the second position, a first trajectory is formed to drive the needle bar to descend to complete the hooking of the thread in cooperation with the rotation of the shuttle in the unwinding process of the balance; in the process that the upper cam bearing moves from the lowest position to the fourth position through the third position, a second trajectory is formed to drive the needle bar to descend to complete the hooking of the thread in cooperation with the unwinding of the shuttle in the rotation process of the shuttle; in the process that the upper cam bearing moves from the fourth position to the first position through the third position, the lowest position and the second position, a third trajectory is formed to drive the needle bar to ascend to start the winding of the thread and to drive the needle bar to ascend and descend to complete the winding of the thread in cooperation with the rotation of the shuttle in the winding process of the balance; and the first trajectory, the second trajectory and the third trajectory constitute a stroke trajectory.

[0006] In some embodiments, one end of the balance is pivotally connected to the thread lifting stroke adjusting seat through an adjustable height assembly.

[0007] In some embodiments, the thread lifting stroke adjusting seat is provided with an adjusting hole extending upward and downward, the adjustable height assembly comprises a balance connecting screw and a balance connecting nut, and the balance connecting screw and the balance connecting nut are used to fix the balance at a thread lifting height position in the adjusting hole after being tightened.

[0008] In some embodiments, the machine base is provided with a needle bar stroke cam slide plate seat for guiding the lifting motion of the needle bar stroke cam slide plate.

[0009] In some of the embodiments, a needle bar joint is arranged on the machine base to guide the lifting movement of the needle bar connecting rod.

[0010] In the second aspect, the embodiments of the present application provide a special trajectory cam needle bar stroke thread picking method, which realizes the following operation steps: rotating the needle bar crank to drive the needle bar stroke cam to move along the stroke trajectory through the upper cam bearing and synchronously drive the needle bar lifting movement through the needle bar connecting rod, to cooperate with the rotation of the shuttle to drive the synchronous movement of the needle bar and the balance wheel to complete the thread picking and take-up; in the process of the balance wheel take-up, the needle bar is driven to lift to start the take-up in cooperation with the rotation of the shuttle; in the process of the balance wheel take-up, the needle bar is driven to lift to start the take-up in cooperation with the rotation of the shuttle.

[0011] Compared with the related art, the sewing machine provided by the embodiments of the present application has the beneficial effects that: the needle bar crank is rotated to drive the stroke cam to move along the stroke trajectory through the upper cam bearing, to cooperate with the rotation of the shuttle to drive the synchronous movement of the needle bar and the balance wheel to complete the thread picking and take-up; in the process of the balance wheel take-up, the needle bar is driven to lift to start the take-up in cooperation with the rotation of the shuttle; in the process of the balance wheel take-up, the needle bar is driven to lift to start the take-up in cooperation with the rotation of the shuttle. The stroke trajectory of the present application is different from the prior art and has particularity, thereby realizing a stitch with stronger stability, and greatly improving the synchronization reliability and stability of the needle bar stroke.

[0012] The details of one or more embodiments of the present application are presented in the following drawings and description to make other features, objects and advantages of the present application more apparent. BRIEF DESCRIPTION OF DRAWINGS

[0013] The drawings described herein are intended to provide further understanding of the present application, and form a part of the present application. The illustrative embodiments of the present application and their description serve to explain the present application without forming an improper limitation of the present application. In the drawings:

[0014] Fig. 1 is a state change schematic diagram of the circumferential motion of the thread picking, thread picking and take-up of the needle bar, the stroke cam, the needle bar, the upper cam bearing and the balance wheel of the embodiments of the present application.

[0015] Fig. 2 is a structure diagram of the sewing machine of the embodiments of the present application.

[0016] Fig. 3 is a structure diagram of the trajectory guide groove of the stroke cam of the embodiments of the present application. EMBODIMENT

[0017] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be described and explained below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application and should not be used to limit the present application. Based on the embodiments provided by the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application. In addition, it should be understood that although the efforts made in this development process can be complex and lengthy, some design, manufacture or production changes made on the basis of the technical content disclosed in the present application by those of ordinary skill in the art related to the disclosed content should be considered as routine technical means and should not be understood as insufficient disclosure of the present application.

[0018] In the present application, the term "embodiment" means that the specific features, structures or properties described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in the present application can be combined with other embodiments without conflict.

[0019] Unless otherwise defined, the technical terms or scientific terms involved in the present application should be understood as the usual meaning by those of ordinary skill in the art to which the present application belongs. The terms "one", "a", "an", "the" and the like similar words involved in the present application do not represent quantity limitation, but can represent singular or plural. The terms "include", "contain", "have" and any variations thereof involved in the present application are intended to cover non-exclusive inclusion; for example, a process, method, system, product or device including a series of steps or modules is not limited to the listed steps or units, but can also include steps or units not listed, or can also include other steps or units inherent to the process, method, product or device. The terms "connect", "connect", "couple" and the like similar words involved in the present application are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. The term "multiple" involved in the present application means greater than or equal to two. The term "and / or" describes the association between the associated objects, which means that there can be three relationships, for example, "A and / or B" can represent three cases: A exists alone, A and B exist together, and B exists alone. The terms "first", "second", "third" and the like involved in the present application are only to distinguish similar objects, and do not represent a specific order for the objects.

[0020] As Figs. 1-3As shown, the special trajectory cam needle bar stroke thread lifting device provided by the embodiment of the application comprises a machine base, wherein the machine base is provided with a needle bar 22, a scale 18, a needle bar stroke cam slide plate 7, a needle bar stroke cam 5, a needle bar crank 1 and a shuttle 59. The central shaft of the needle bar crank 1 is used as a coaxial input end of external power. The needle bar crank 1 is assembled with an upper cam bearing 81 through a cam bearing nut. The needle bar stroke cam slide plate 7 is assembled on the needle bar stroke cam 5 through a needle bar stroke cam fixing screw 6. One end of the scale 18 is pivotally connected to a thread lifting stroke adjusting seat 16 of the machine base. The thread lifting stroke adjusting seat 16 is assembled and fixed on the machine base through a thread lifting stroke adjusting seat screw 17. The scale 18 is provided with an elongated guide hole. The top of the needle bar stroke cam slide plate 7 is assembled with a cam bearing 82 movably inserted into the guide hole through a thread lifting stroke slide block seat 14 and a thread lifting stroke slide block seat screw 15. The cam bearing 82 is rotatably assembled in the thread lifting stroke slide block seat 14 through a cam bearing nut. The needle bar 22 is assembled at the bottom of the needle bar stroke cam slide plate 7 through a needle bar connecting rod 25 and a needle bar connecting rod pin 9 and a needle bar joint 23 connected at both ends of the needle bar connecting rod 25. The needle bar joint 23 at one end of the needle bar connecting rod 25 penetrates through the needle bar connecting rod 25 and is assembled and connected with a needle bar joint slide block 26. The needle bar joint slide block 26 is slidably assembled on a needle bar joint 27. The needle bar stroke cam 5 is provided with a trajectory guide groove forming a stroke trajectory. The trajectory guide groove has a first trajectory guide groove and a second trajectory guide groove respectively extending to both sides with the lowest position 503 as the center. The upper cam bearing 81 is movably arranged in the first trajectory guide groove and the second trajectory guide groove. The first trajectory guide groove is provided with a first position 501 with the same trajectory radius as the lowest position 503. The second trajectory guide groove is provided with a fourth position 505 with the same trajectory radius as the lowest position 503. The first position 501 and the lowest position 503 have a second position 502 with a trajectory radius smaller than the lowest position 503. The fourth position 505 and the lowest position 503 have a third position 504 with a trajectory radius smaller than the lowest position 503. The trajectory radius of the second position 502 is smaller than that of the third position 504, that is, the second position 502 is the lowest position of the needle bar 22 in the whole lifting movement, and the shuttle hooking is performed at the lowest position of the needle bar.In other words, when the upper cam bearing 81 moves to the first position 501, the lowest position 503, and the fourth position 505, the hour hand rod 22 is at the same horizontal height. When the upper cam bearing 81 moves to the second position 502 and the third position 504, the hour hand rod 22 decreases in relative horizontal height. During the process of the upper cam bearing 81 moving from the first position 501 through the second position 502 to the lowest position 503, it forms a downward movement of the needle rod 22 driven by the rotation of the shuttle 59 during the thread feeding process of the balance 18 to complete the first trajectory of the thread hooking. During the process of the upper cam bearing 81 moving from the lowest position 503 through the third position 504 to the fourth position 505, it forms a downward movement of the needle rod 22 driven by the rotation of the shuttle 59 to complete the first trajectory of the thread hooking. During the rotation of the shuttle 59 to complete the hooking of the thread, a second trajectory is formed to coordinate with the shuttle 59 in releasing the thread. During the process of the upper cam bearing 81 moving from the fourth position 505 to the first position 501 in sequence through the third position 504, the lowest position 503, and the second position 502, a third trajectory is formed. First, during the rotation of the shuttle 59 to complete the hooking of the thread, the needle bar 22 is driven to rise to start taking in the thread. Then, during the process of taking in the thread with the balance 18, the needle bar 22 is driven to move up and down in coordination with the rotation of the shuttle 59 to complete the taking in the thread. The first trajectory, the second trajectory, and the third trajectory constitute the stroke trajectory. The upper cam bearing 81 moves according to the stroke trajectory to realize the synchronous coordinated movement of the needle bar, the balance, and the shuttle.

[0021] To address this, this invention provides a special trajectory cam needle bar stroke take-up method, employing the special trajectory cam needle bar stroke take-up device described above, and implementing the following operational steps: The needle bar crank 1 is rotated to drive the needle bar stroke cam 5 along its stroke trajectory via the upper cam bearing 81, and the needle bar 22 is simultaneously driven to rise and fall via the needle bar connecting rod 25, coordinating with the rotation of the shuttle 59 to drive the synchronous movement of the needle bar 22 and the balance 18 to complete the hooking and take-up / release of thread; during the thread release process of the balance 18, the needle bar 22 is driven to descend in coordination with the rotation of the shuttle 59 to complete the hooking of thread; during the rotation of the shuttle 59 after hooking the thread, the needle bar 22 is driven to rise to begin take-up of thread; during the take-up process of the balance 22, the needle bar 22 is driven to rise and fall in coordination with the rotation of the shuttle 59 to complete the take-up of thread. In this embodiment, the trajectory radius refers to the rotation radius A of the upper cam bearing 81. Through the aforementioned stroke take-up device and method, during the thread release and holding process of the balance 18, i.e., before the thread take-up process of the balance 18, the needle bar 22 first performs a short-range downward stroke to cooperate with the shuttle to complete the hooking of the thread during the thread release and holding process. This works well with the rotation of the shuttle 59, thereby improving the stability and reliability of the synchronization between hooking and thread release and take-up. In this embodiment, the top of the needle bar 22 is fitted with an upper needle bar sleeve 28, and the bottom of the needle bar 22 is fitted with a lower needle bar sleeve 29. At the lower end of the lower needle bar sleeve 29, a machine needle 31 is assembled through an upper needle screw 30 and a needle bar thread guide ring 32.

[0022] The working principle of the embodiment of the present application is as follows: eight state changes are divided, which are the first state B1, the second state B2, the third state B3, the fourth state B4, the fifth state B5, the sixth state B6, the seventh state B7 and the eighth state B8. In the process from the first state B1 to the fifth state B5, the wire releasing of the balance is completed. In the process from the first state B1 to the third state B3, the wire hooking process of the shuttle is completed. In the process from the third state B3 to the fifth state B5, the wire releasing process of the shuttle is completed. In the process from the fifth state B5 to the sixth state B6, the wire releasing process of the shuttle and the wire releasing process of the balance are completed. In the process from the sixth state B6 to the eighth state B8, the wire releasing process of the shuttle and the wire releasing process of the balance are completed. In the process from the eighth state B8 to the first state B1, the wire releasing process of the balance and the rotation resetting process of the shuttle (starting the next stroke) are completed. Specifically, in the wire releasing process of the balance 18, the shuttle 59 rotates synchronously to reset. After the wire releasing of the balance 18 is completed, the balance 18 is in the wire releasing completed maintaining state. In the wire releasing completed maintaining state of the balance, the upper cam bearing 81 is driven by the needle bar crank 1 to move from the first position 501 to the lowest position 503 through the second position 502, thereby synchronously driving the needle bar 22 to descend to complete the wire hooking and resetting. The upper cam bearing 81 is driven by the needle bar crank 1 to move from the lowest position 503 to the fourth position 505 through the third position 504, thereby synchronously driving the needle bar 22 to slightly ascend and descend. In this process, the shuttle 59 is in the wire releasing process. The upper cam bearing 81 is driven by the needle bar crank 1 to move from the fourth position 505 to the first position 501 through the third position 504, the lowest position 503 and the second position 502, thereby synchronously driving the needle bar 22 to greatly ascend and descend. In this process, the shuttle 59 completes the wire winding, which is divided into the wire winding process of the shuttle and the wire winding completed maintaining process of the shuttle. At the same time, in this process, the balance 22 completes the wire winding, which is divided into the wire winding process of the balance and the wire winding completed maintaining process of the balance. The wire winding process of the balance and the wire winding process of the shuttle are synchronously performed, and the wire winding completed maintaining process of the balance and the wire winding completed maintaining process of the shuttle are synchronously performed. The balance 22 re-enters the wire releasing process under the driving of the needle bar crank 1, and the above process is repeated to start the next stroke.

[0023] As Fig. 2As shown, one end of the balance 18 of the present embodiment is pivoted to the thread tension stroke adjusting seat 16 through an adjustable height assembly. The thread tension stroke adjusting seat 16 is provided with an adjusting hole extending upward and downward, and the adjustable height assembly includes a balance connecting screw 19 and a balance connecting nut 20, which are used to fix the balance 18 in the thread tension height position in the adjusting hole after being tightened. The machine base is provided with a needle bar stroke cam slide plate seat 10 and a needle bar stroke cam slide plate seat pressing plate 11 for guiding the lifting movement of the needle bar stroke cam slide plate 7, and the needle bar stroke cam slide plate seat 10 and the needle bar stroke cam slide plate seat pressing plate 11 are fixedly assembled by a needle bar stroke cam slide plate seat pressing plate screw 12 and form a sliding channel for the needle bar stroke cam slide plate 7, and the needle bar stroke cam slide plate seat 10 is fixedly assembled on the machine base by a needle bar stroke cam slide plate seat screw 13.

[0024] As Fig. 2The main structure of the sewing machine provided by the embodiment of the application is shown in the figure, which comprises a synchronous transmission device, a shuttle device and the trajectory cam needle bar stroke thread tensioning device as described above. The synchronous transmission device, the shuttle device comprises a first transmission assembly, a shuttle shaft 55 and a shuttle 59, the shuttle 59 is assembled on the shuttle shaft 55, the first transmission assembly is in transmission connection with the first output end of the synchronous transmission device, and the upper cam bearing 81 in the trajectory cam needle bar stroke thread tensioning device is in transmission connection with the second output end of the synchronous transmission device. The synchronous transmission device comprises an upper shaft 34 and a vertical shaft 41 in transmission through gears. The upper shaft 34 is used to drive the trajectory cam needle bar stroke thread tensioning device to realize the thread tensioning action, and the vertical shaft 41 is used to drive the shuttle device to realize the thread hooking action. One end of the upper shaft 34 is coaxially provided with an upper shaft front sleeve 33 and is locked and assembled with the needle bar crank 1 through a needle bar crank screw 2, the other end of the upper shaft 34 is coaxially assembled with an upper shaft gear 36 through a screw, the upper end of the vertical shaft 41 is coaxially assembled with a vertical shaft gear 37 through a screw, and the upper shaft 34 and the vertical shaft 41 are in synchronous transmission through the mutual meshing of the upper shaft gear 36 and the vertical shaft gear 37, so as to realize the synchronous linkage of the shuttle 59 and the needle bar 22 and the sky pivot 18. The end of the upper shaft 34 of the embodiment is connected with external power transmission, the direct power output of the external power to the upper shaft 34 drives the upper shaft 34 to drive the trajectory cam needle bar stroke thread tensioning device to realize the thread hooking and tensioning, and the meshing of the upper shaft gear 36 and the vertical shaft gear 37 realizes precise and stable transmission, realizes the transmission to the vertical shaft 41, the vertical shaft 41 drives the lower thread hooking connecting rod 47 through the first transmission assembly, so as to realize the driving to the shuttle bed swing sector gear 49, and then controls the thread hooking action of the shuttle 59. The synchronous transmission device realizes precise and stable power output through gear transmission, simplifies the transmission structure, and is helpful to the reduction of the overall size of the sewing machine.The first transmission assembly of the shuttle device comprises a line hooking cam 44, a lower line hooking connecting rod 47 and a shuttle bed swinging sector gear 49. The line hooking cam 44 is coaxially assembled on the lower end of the vertical shaft 41 by means of a screw. The line hooking cam 44 has an eccentric annular slide rail. One end of the lower line hooking connecting rod 47 is slidably arranged in the annular slide rail by means of a lower cam bearing 83. The line hooking cam 44 and the lower line hooking crank positioning plate 46 are in transmission connection with the fork-shaped part of the lower line hooking connecting rod 47 through the lower line hooking crank insertion slide block 45. The lower line hooking connecting rod 47 is driven to drive the transmission of the shuttle bed swinging sector gear 49 by the sliding of the lower cam bearing 83 along the annular slide rail in the rotating process of the line hooking cam 44. The other end of the lower line hooking connecting rod 47 is pivotally connected with the middle part of the shuttle bed swinging sector gear 49. One end of the shuttle bed swinging sector gear 49 is in meshing transmission with the input end of the shuttle shaft 55. The other end of the shuttle bed swinging sector gear 49 is pivotally connected to the bottom of the shuttle edge seat 70. The shuttle bed swinging sector gear 49 is driven to swing back and forth in the swinging process of the lower line hooking connecting rod 47, so as to drive the rotation of the shuttle bed shaft gear 52 coaxially and transmissionally assembled on the lower end of the shuttle shaft 55. The forward and reverse rotation of the shuttle bed shaft gear 52 is realized by the back and forth swinging of the shuttle bed swinging sector gear 49, and then the periodic forward and reverse rotation of the shuttle 59 is realized. The shuttle column 68 is assembled on the shuttle edge seat 70, the shuttle shaft 55 is arranged in the hollow chamber of the shuttle column 68, and the needle plate 62 is pivotally connected to the bottom of the shuttle column 68 through the needle plate positioning pin 63, the needle plate positioning pin screw 64 and the needle plate positioning plate 65. The sewing machine structure with the above structure has strong reliability, thereby bringing better operation stability.

[0025] Those skilled in the art should understand that each technical feature of the above embodiments can be combined arbitrarily, and in order to make the description concise, each technical feature in the above embodiments is not described in all possible combinations, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the description.

[0026] The above embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as the limitation of the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A special trajectory cam needle bar stroke thread take-up device comprising a frame, characterized in that, The machine base is provided with a needle bar, a jack, a needle bar stroke cam slide, a needle bar stroke cam, a needle bar crank and a shuttle, the center shaft of the needle bar crank is coaxial with the external power input, the needle bar crank is provided with an upper cam bearing, the needle bar stroke cam slide is assembled on the needle bar stroke cam, one end of the jack is pivoted on the thread lifting stroke adjusting seat of the machine base, the jack is provided with an elongated guide hole, the needle bar stroke cam slide is provided with a cam bearing movably inserted into the guide hole, the needle bar is assembled on the needle bar stroke cam slide through a needle bar connecting rod; the needle bar stroke cam is provided with a stroke track guide groove, the stroke track guide groove extends to the first track guide groove and the second track guide groove on both sides with the lowest position as the center, the upper cam bearing is movably arranged in the first track guide groove and the second track guide groove, the first position with the same track radius as the lowest position is arranged in the first track guide groove, the fourth position with the same track radius as the lowest position is arranged in the second track guide groove, the second position with a track radius smaller than the lowest position is arranged between the first position and the lowest position, the third position with a track radius smaller than the lowest position is arranged between the fourth position and the lowest position; In the process that the upper cam bearing moves from the first position to the lowest position through the second position, the first track is formed to drive the needle bar to descend to complete the thread lifting in cooperation with the rotation of the shuttle in the thread releasing process of the jack; in the process that the upper cam bearing moves from the lowest position to the fourth position through the third position, the second track is formed to drive the needle bar to lift to start the thread winding in the rotation process of the shuttle to complete the thread lifting; in the process that the upper cam bearing moves from the fourth position to the first position through the third position, the lowest position and the second position, the third track is formed to drive the needle bar to descend to complete the thread winding in cooperation with the rotation of the shuttle in the thread releasing process of the jack, the first track, the second track and the third track constitute the stroke track, and the upper cam bearing moves according to the stroke track to realize the synchronous cooperation of the needle bar, the jack and the shuttle; The needle bar is at the same horizontal height when the upper cam bearing moves to the first position, the lowest position and the fourth position, and the needle bar is lowered in relative horizontal height when the upper cam bearing moves to the second position and the third position; One end of the jack is pivoted on the thread lifting stroke adjusting seat through an adjustable height assembly; The stroke thread lifting method comprises the following operation steps: rotating the needle bar crank to drive the needle bar stroke cam to move along the stroke track through the upper cam bearing and to synchronously drive the needle bar to lift and descend through the needle bar connecting rod, to drive the needle bar and the jack to move synchronously to complete the thread lifting and the thread winding in cooperation with the rotation of the shuttle; driving the needle bar to descend to complete the thread lifting in cooperation with the rotation of the shuttle in the thread releasing process of the jack, driving the needle bar to lift to start the thread winding in the rotation process of the shuttle to complete the thread lifting, and driving the needle bar to lift and descend to complete the thread winding in cooperation with the rotation of the shuttle in the thread releasing process of the jack.

2. A special profile cam needle bar stroke thread take-up according to claim 1, characterized in that The thread tension adjusting seat is provided with an adjusting hole extending upward and downward, the height-adjustable assembly comprises a scale pan connecting screw and a scale pan connecting nut, and the scale pan connecting screw and the scale pan connecting nut are used to fix the scale pan in the thread tension height position in the adjusting hole after being screwed.

3. A special profile cam needle bar stroke thread take-up according to claim 1, characterized in that, The machine base is provided with a needle bar stroke cam slide plate seat for guiding the lifting movement of the needle bar stroke cam slide plate.

4. A special profile cam needle bar stroke thread take-up according to claim 1 characterized in that, The machine base is provided with a needle bar joint for guiding the lifting movement of the needle bar connecting rod.

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