A sewing machine anti-stitch skipping control method

Abstract

The present invention provides a sewing machine anti-skipping control method, comprising: configuring a telescopic drive source installed on a needle bar and connected to a machine needle, wherein the machine needle is movable up and down and inserted into a through hole at the lower end of the needle bar; the sewing machine starts sewing; the needle bar drives the machine needle to move downward, and after the machine needle enters the rotary hook, the electronic control unit controls the telescopic drive source to operate, and the telescopic drive source drives the machine needle to move downward a preset distance relative to the needle bar; the needle bar drives the machine needle to move downward to the lowest point; the needle bar drives the machine needle to move upward, and the machine needle first enters the thread hooking stage, and the electronic control unit controls the telescopic drive source to reset, and the telescopic drive source drives the machine needle to move upward relative to the needle bar, and the machine needle resets; the needle bar drives the machine needle to continue to move upward to the thread hooking point, and the shuttle tip of the rotary hook hooks the thread loop formed at the lower end of the machine needle; the needle bar drives the machine needle to continue to move upward to the highest point. This application enables the machine needle to have a lower position when it moves downward to the lowest point, increases the amount of stitches brought under the fabric by the machine needle, and forms a larger thread loop near the needle hole at the lower end of the needle, thereby achieving anti-skipping stitch.

Description

Technical Field

[0001] The present invention relates to the technical field of sewing machines, in particular to a sewing machine anti-stitch skipping control method. Background Art

[0002] Currently, there are several types of sewing machines, including lockstitch machines, overlock machines, and interlock machines. Among them, the lockstitch machine is a type of sewing machine that forms lockstitches. During the sewing process, the lockstitch machine forms lockstitches on the sewn fabric through the coordination of the up and down movement of the needle and the rotation of the rotary shuttle. However, in the actual sewing process, due to improper coordination between the needle and the rotary shuttle, the undesirable phenomenon of skipped stitches may occur, and lockstitches cannot be formed. This is especially true when sewing elastic fabrics and high-density fabrics, as well as when sewing fabrics with excessive stalks or thickness. The main reason for the skipped stitch problem is that when the rotary shuttle hooks the thread, an effective thread loop cannot be formed at the needle hole at the lower end of the needle. The thread loop is too small to be captured by the shuttle tip.

[0003] In existing technology, when a lockstitch sewing machine experiences skipped stitches, a professional mechanic needs to adjust the distance between the hook and the needle to resolve the issue. This approach places high demands on the mechanic's technical skills. Furthermore, even after adjustments by a professional mechanic, the skipped stitch problem can recur. Ultimately, skipped stitches can lead to poor seams, substandard sewing results, reduced production efficiency, and an inability to meet customer needs. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a sewing machine anti-stitch skipping control method, so that a larger thread loop is formed at the needle hole at the lower end of the needle.

[0005] To achieve the above object, the present invention provides a sewing machine anti-stitch skipping control method, the sewing machine anti-stitch skipping control method comprising the following steps:

[0006] S1. A sewing machine is provided with an electronic control unit, a needle bar movably disposed vertically within a sewing machine housing, a telescopic drive source mounted on the needle bar, a needle drivingly connected to the telescopic drive source, and a rotary hook rotatably supported within a base plate of the sewing machine, wherein a through hole extending vertically therethrough is defined at the lower end of the needle bar, the needle movably disposed vertically within the through hole at the lower end of the needle bar, and the electronic control unit is connected to the telescopic drive source.

[0007] S2. During the sewing process, the needle of the sewing machine has a downward phase, moving from the highest point to the lowest point, and an upward phase, moving from the lowest point to the highest point. The downward phase includes a first downward phase before the needle enters the rotary hook, and a second downward phase after the needle enters the rotary hook. The upward phase includes a thread hooking phase, a thread hooking point, and a rising and resetting phase.

[0008] S3, the sewing machine starts sewing;

[0009] S4, the needle bar drives the needle to move downward, and the needle first completes the first downward stage;

[0010] Afterwards, the needle enters the second downward phase, and the electronic control unit controls the telescopic drive source to move, and the telescopic drive source drives the needle to move downward a preset distance relative to the needle bar;

[0011] The needle bar drives the needle to continue to move downward until the needle moves to the lowest point, and the needle completes the second downward stage;

[0012] S5: The needle bar drives the sewing needle to move upward, and the sewing needle first enters the thread hooking stage. The electronic control unit controls the retractable drive source to reset, and the retractable drive source drives the sewing needle to move upward relative to the needle bar, and the sewing needle is reset;

[0013] The needle bar drives the needle to continue to move upward, and the needle moves up to the thread hooking point. At this time, the hook tip of the rotary hook hooks the thread loop formed at the lower end of the needle;

[0014] The needle bar drives the needle to continue to move upward until the needle moves to the highest point, and the needle completes the recovery and reset stage;

[0015] S6. Repeat steps S4 and S5 until sewing is completed.

[0016] Furthermore, a mounting inner cavity communicating with the through hole is provided in the needle rod, and the telescopic driving source is a bidirectional electromagnet fixed at the lower end of the mounting inner cavity, and the iron core of the bidirectional electromagnet is connected to the machine needle.

[0017] Furthermore, the needle rod is provided with an installation inner cavity communicated with the through hole, the telescopic driving source is a one-way electromagnet fixed at the lower end of the installation inner cavity, a reset spring is sleeved on the iron core of the one-way electromagnet, and the iron core of the one-way electromagnet is connected to the machine needle.

[0018] Furthermore, the sewing machine is also equipped with a bushing fixed in the casing, a conductive strip fixed in the bushing, a conductive contact fixed in the needle bar, and a connecting circuit. The needle bar is movably arranged in the bushing, and the electronic control unit is connected to the conductive strip via the connecting circuit. The conductive strip is in contact with the conductive contact, and the conductive contact is connected to the telescopic drive source.

[0019] Furthermore, the conductive strip is linear and extends straight up and down along the moving direction of the needle rod, and the conductive strip is fixed on the inner wall surface of the bushing.

[0020] Furthermore, the conductive strip is annular and fixed on the inner wall surface of the bushing.

[0021] Furthermore, the conductive contact is cylindrical and extends straight along the radial direction of the needle rod.

[0022] Furthermore, the conductive contact is annular and fixed on the outer wall surface of the needle rod.

[0023] As described above, the sewing machine anti-stitch skipping control method according to the present invention has the following beneficial effects:

[0024] In the present application, the needle bar is moved up and down to drive the machine needle to move up and down together, thereby performing the piercing action. In particular, the present application drives the machine needle to move up and down relative to the needle bar through a telescopic drive source. In this way, after the needle bar drives the machine needle downward to enter the rotary hook, the telescopic drive source drives the machine needle to extend downward relative to the needle bar in the piercing direction, so that the machine needle has a lower position when it moves down to the lowest point, thereby increasing the amount of stitches brought under the fabric by the machine needle; thereafter, before the needle bar drives the machine needle upward and before the rotary hook completes the thread hooking, the telescopic drive source drives the machine needle to move upward relative to the needle bar in the rising direction and reset, thereby forming a large thread loop near the needle hole at the lower end of the needle; thereafter, the rotary hook hooks the thread, and the shuttle tip of the rotary hook easily and stably captures the large thread loop, greatly reducing the probability that the shuttle tip of the rotary hook cannot hook the thread loop, and finally reliably achieving anti-skipping stitches. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the movement stroke of the machine needle moving up and down once in this application.

[0026] Figure 2 This is the control principle diagram of the anti-skipping needle control method for the sewing machine in this application.

[0027] Figure 3 This is a schematic structural diagram of the sewing machine for this application.

[0028] Figure 4 This is a structural diagram of the anti-needle skipping mechanism of this application, and the casing is omitted in this figure.

[0029] Figure 5 for Figure 4 Cross-section at the conductive strips and contacts.

[0030] Figure 6 Schematic diagram of the installation of a straight conductive strip in a bushing.

[0031] Figure 7 Schematic diagram of the installation of annular conductive strips in the bushing.

[0032] Component number description

[0033] 10. Chassis

[0034] 20 needle bars

[0035] 21 through holes

[0036] 22 Install the inner cavity

[0037] 30 needles

[0038] 40 telescopic drive source

[0039] 50 Bushing

[0040] 60 conductive strips

[0041] 70 conductive contacts

[0042] 80 Downward Phase

[0043] 81 First Downward Phase

[0044] 82 Second Downward Phase

[0045] 90 Rising Stage

[0046] 91 Outline Stage

[0047] 92 hook points

[0048] 93 Recovery and reset phase

[0049] 110 hook

[0050] 120 base plate

[0051] H Highest point

[0052] L lowest point DETAILED DESCRIPTION

[0053] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0054] It should be noted that the structures, proportions, sizes, etc. depicted in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions for the implementation of the present invention. Therefore, they have no substantial technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose of the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0055] It should also be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element through an intervening element.

[0056] In addition, the descriptions of "first", "second", etc. in this application are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0057] The present application provides a sewing machine anti-stitching control method for a sewing machine. The sewing machine is a flat sewing machine. Figure 3 As shown, the sewing machine includes a fixed housing 10 and a base plate 120, a main shaft rotatably supported in the housing 10, a main motor driving the main shaft, a material-piercing mechanism mounted in the housing 10, a thread-taking mechanism mounted in the base plate 120, and an electronic control unit connected to the main motor. The material-piercing mechanism includes a needle bar 20 movably mounted in the housing 10, a needle 30 mounted at the lower end of the needle bar 20, and a material-piercing transmission assembly. The upper end of the needle bar 20 is connected to the main shaft via the material-piercing transmission assembly, meaning that the material-piercing mechanism is driven by the main motor. The thread-taking mechanism includes a lower shaft rotatably supported in the base plate 120 and a rotary hook 110 fixed to the left end of the lower shaft. The lower shaft can be in driving connection with the main shaft, so that the thread-taking mechanism also receives its driving force from the main motor; alternatively, the lower shaft can be driven by a separate motor independent of the main motor.

[0058] During the sewing process, the main shaft drives the needle bar 20 to move up and down through the material transmission assembly, and the needle bar 20 drives the needle 30 to move up and down; the main shaft rotates one circle, and the needle 30 moves up and down once. Based on this, during the process of the needle 30 moving up and down once, Figure 1As shown, the needle 30 has a highest point H and a lowest point L, and the movement stroke of the needle 30 has a descending stage 80 moving from the highest point H to the lowest point L, and an ascending stage 90 moving from the lowest point L to the highest point H. In the descending stage 80 of the needle 30, based on the moment when the needle 30 just enters the rotary hook 110, the descending stage 80 is divided into a first descending stage 81 before the needle 30 enters the rotary hook 110, and a second descending stage 82 after the needle 30 enters the rotary hook 110. Then, the highest point H of the needle 30, the first descending stage 81, the second descending stage 82 and the lowest point L of the needle 30 are successively connected along the piercing direction when the needle 30 moves downward. In the rising stage 90 of the needle 30, the tip of the shuttle 110 will hook the thread loop formed at the lower end of the needle 30. The position of the needle 30 at the moment when the tip of the shuttle 110 hooks the thread loop is defined as the hooking point 92. Based on the hooking point 92, the rising stage 90 is divided into the hooking stage 91 in which the needle 30 moves upward toward the hooking point 92, and the recovery and reset stage 93 in which the needle 30 moves upward away from the hooking point 92. The lowest point L of the needle 30, the hooking stage 91, the hooking point 92, the recovery and reset stage 93 and the highest point H of the needle 30 are successively connected along the recovery direction when the needle 30 moves upward. The recovery and reset stage 93 is also the stage in which the needle 30 moves out of the shuttle 110 and away from the shuttle 110. The electronic control unit determines whether the needle 30 enters the second downward phase 82 when moving downward, and determines whether the needle 30 reaches the hooking point 92 when moving upward based on the rotation angle information of the main shaft.

[0059] like Figure 2 As shown, the sewing machine anti-stitch skipping control method involved in the present application includes the following steps.

[0060] Step S1, configuring an anti-stitch skipping mechanism in the sewing machine; Figure 4 As shown, in addition to the above-mentioned electronic control unit, housing 10, needle bar 20 and needle 30, the anti-needle jumping mechanism also includes a telescopic drive source 40 installed on the needle bar 20. The lower end of the needle bar 20 is provided with a through hole 21 that passes through the upper and lower ends. The needle 30 can be moved up and down in the through hole 21 at the lower end of the needle bar 20. The telescopic drive source 40 is connected to the needle 30 for driving the needle 30 to move up and down relative to the needle bar 20. The electronic control unit is connected to the telescopic drive source 40.

[0061] Step S2: During the sewing process, the sewing machine Figure 1 As shown, the movement stroke of the needle 30 has a downward stage 80 moving from the highest point H to the lowest point L, and an upward stage 90 moving from the lowest point L to the highest point H. The downward stage 80 successively includes the first downward stage 81 before the needle 30 enters the rotary hook 110, and the second downward stage 82 after the needle 30 enters the rotary hook 110. The upward stage 90 successively includes the line hooking stage 91, the line hooking point 92 and the recovery and reset stage 93.

[0062] Step S3: The sewing machine starts sewing.

[0063] Step S4: The needle bar 20 drives the needle 30 to move downward, and the needle 30 first completes the first downward phase 81;

[0064] Afterwards, the needle bar 20 drives the needle 30 to continue to move downward, and the needle 30 enters the second downward stage 82. The needle 30 enters the rotary hook 110, and the electronic control unit controls the telescopic drive source 40 to move downward relative to the needle bar 20 by a preset distance.

[0065] The needle bar 20 drives the needle 30 to continue moving downward until the needle 30 moves to the lowest point L, and the needle 30 completes the second downward stage 82; because the telescopic drive source 40 drives the needle 30 to extend downward relative to the needle bar 20 along the piercing direction, when the needle 30 moves down to the lowest point, compared with the prior art, the position of the lowest point L of the needle 30 in this application is lower, or in other words, the present application makes the needle 30 have a lower position when it moves down to the lowest point L, thereby increasing the amount of stitches brought under the fabric by the needle 30.

[0066] Step S5: The needle bar 20 drives the sewing needle 30 to move upward, and the sewing needle 30 first enters the thread hooking stage 91. The electronic control unit controls the retractable drive source 40 to reset. The retractable drive source 40 drives the sewing needle 30 to move upward relative to the needle bar 20, and the sewing needle 30 resets, thereby forming a large thread loop near the needle hole at the lower end of the sewing needle 30.

[0067] The needle bar 20 drives the needle 30 to continue to move upward, and the needle 30 moves up to the thread hooking point 92. At this time, the hook tip of the rotary hook 110 hooks the thread loop formed at the lower end of the needle 30.

[0068] The needle bar 20 drives the needle 30 to continue to move upward until the needle 30 moves to the highest point H, and the needle 30 completes the recovery and reset stage 93.

[0069] Step S6: Repeat steps S4 and S5 until sewing is completed.

[0070] Therefore, the present application enables the needle 30 to move down and up relative to the needle bar 20, and drives the needle 30 to move up and down relative to the needle bar 20 through the telescopic drive source 40, so as to change the relative position of the needle 30 and the needle bar 20 after the needle 30 enters the rotary shuttle 110 during the downward process. In this way, first, after the needle bar 20 drives the needle 30 downward to enter the rotary hook 110, the telescopic drive source 40 drives the needle 30 to extend downward relative to the needle bar 20 in the direction of piercing the material, so that the needle 30 has a lower position when it moves down to the lowest point L, thereby increasing the amount of stitches brought under the fabric by the needle 30; then, after the needle bar 20 drives the needle 30 upward and before the rotary hook 110 completes the thread hooking, the telescopic drive source 40 drives the needle 30 to move upward relative to the needle bar 20 in the recovery direction and reset, thereby forming a large thread loop near the needle hole at the lower end of the needle 30, and cooperating with the rotary hook 110 to perform normal thread hooking action; then, the rotary hook 110 hooks the thread, and the shuttle tip of the rotary hook 110 easily and stably captures the large thread loop, greatly reducing the probability that the shuttle tip of the rotary hook 110 cannot hook the thread loop. Finally, the present application reliably realizes anti-skipping stitches, effectively improves production efficiency while reducing poor stitches, ensures that the sewing effect meets the requirements, and creates more benefits.

[0071] In addition, in the present application, the telescopic drive source 40 drives the needle 30 to extend downward relative to the needle rod 20 in the piercing direction after the needle 30 enters the rotary hook 110. The position of the needle 30 before entering the rotary hook 110 does not change, which avoids the needle 30 entering the rotary hook 110 in advance due to its position being too low before entering the rotary hook 110, thereby preventing the needle 30 from piercing the rotary hook 110, and preventing the rotary hook 110 from hitting the needle, thereby realizing a protection mechanism during the downward piercing process of the needle 30.

[0072] Furthermore, if Figure 4 As shown, the needle bar 20 is provided with a mounting cavity 22 that communicates with the through hole 21, and the telescopic drive source 40 is fixed in the mounting cavity 22 of the needle bar 20 and near the through hole 21 at the lower end of the needle bar 20. The telescopic drive source 40 is preferably a bidirectional electromagnet fixed at the lower end of the mounting cavity 22, wherein the iron core of the bidirectional electromagnet is connected to the upper end of the needle 30; when the bidirectional electromagnet is energized, its iron core extends downward, driving the needle 30 to extend downward; when the bidirectional electromagnet is de-energized, its iron core retracts upward, driving the needle 30 to return upward. Alternatively, the telescopic drive source 40 is a unidirectional electromagnet fixed at the lower end of the mounting cavity 22, wherein a return spring is provided on the iron core of the unidirectional electromagnet, and the iron core of the unidirectional electromagnet is connected to the upper end of the needle 30; when the unidirectional electromagnet is energized, its iron core extends downward, driving the needle 30 to extend downward; when the unidirectional electromagnet is de-energized, its iron core retracts upward under the action of the return spring, driving the needle 30 to return upward.

[0073] Furthermore, based on the structure that the telescopic driving source 40 is a bidirectional electromagnet or a unidirectional electromagnet, as Figure 4 and Figure 5As shown, the anti-needle skipping mechanism also includes a bushing 50 fixed in the housing 10, a conductive strip 60 fixed in the bushing 50, a conductive contact 70 fixed in the needle bar 20, and a connecting circuit. The needle bar 20 is inserted into the bushing 50 so as to be movable up and down. The electronic control unit is connected to the conductive strip 60 via the connecting circuit, and the conductive contact 70 is connected to the telescopic drive source 40. Moreover, during the second downward phase 82 of the downward movement of the needle 30, the conductive strip 60 contacts and cooperates with the conductive contact 70. In this way, the electronic control unit controls the on / off state of the conductive strip 60 through the connecting circuit, thereby controlling the on / off state of the bidirectional electromagnet or the unidirectional electromagnet.

[0074] Preferably, if Figure 6 As shown, the conductive strip 60 is linear and extends straight up and down along the moving direction of the needle rod 20. The conductive strip 60 is fixed on the inner wall surface of the bushing 50. Alternatively, as shown Figure 7 As shown, the conductive strip 60 is annular and fixed on the inner wall surface of the bushing 50 .

[0075] Preferably, the conductive contact 70 is cylindrical and extends straight along the radial direction of the needle rod 20, so that the end of the conductive contact 70 that contacts the conductive strip 60 is a dot. Alternatively, the conductive contact 70 is annular and fixed to the outer wall of the needle rod 20.

[0076] In summary, in the present application, during the second downward stage 82 after the needle 30 enters the rotary hook 110, the electronic control unit controls the bidirectional electromagnet or the unidirectional electromagnet to be energized, driving the needle 30 to extend downward, so that the subsequent needle 30 has a lower position when it moves to the lowest point L, and during the subsequent thread hooking stage 91 when the needle 30 moves upward, the electronic control unit controls the bidirectional electromagnet or the unidirectional electromagnet to be de-energized, driving the needle 30 to rise back upward, thereby forming a larger thread loop near the needle hole at the lower end of the needle 30, and then cooperates with the rotary hook 110 to complete the thread hooking. In addition, the time it takes for the needle 30 to pierce from the highest point H to the lowest point L, the time it takes to rise from the lowest point L to the highest point H, and the time it takes to complete one sewing are all consistent with the corresponding time consumption of conventional sewing.

[0077] This application has the following advantages:

[0078] 1. It is conducive to forming a larger thread loop at the lower end of the needle 30 when the rotary hook 110 hooks the thread, which makes the thread hooking stable and reliable, reduces the probability that the rotary hook 110 cannot hook the thread loop, and thus reduces the occurrence of skipped stitches;

[0079] 2. Enhance the adaptability of the machine to thin and thick materials, and there will be no stitch skipping when switching between thin and thick materials;

[0080] 3. The timing is consistent with the existing sewing action and does not affect the normal sewing effect;

[0081] 4. It has a needle 30 protection mechanism to prevent the needle 30 from breaking due to interference with the rotary hook 110;

[0082] 5. No need for professional debugging, reducing maintenance costs;

[0083] 6. It helps to improve production efficiency and create greater profits.

[0084] In summary, the present invention effectively overcomes various shortcomings of the prior art and has high industrial utilization value.

[0085] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A sewing machine anti-stitch skipping control method, characterized by: The sewing machine anti-stitch skipping control method comprises the following steps: S1. A sewing machine is provided with an electric control unit, a needle bar (20) movably inserted into a sewing machine housing (10), a telescopic drive source (40) mounted on the needle bar (20), a needle (30) transmission-connected to the telescopic drive source (40), and a rotary hook (110) rotatably supported in a sewing machine base (120), wherein a through hole (21) extending vertically through the needle bar (20) is provided at the lower end thereof, the needle (30) is movably inserted into the through hole (21) at the lower end of the needle bar (20), and the electric control unit is connected to the telescopic drive source (40); S2. During the sewing process, the movement stroke of the sewing machine needle (30) includes a descending stage (80) of moving from the highest point (H) to the lowest point (L), and an ascending stage (90) of moving from the lowest point (L) to the highest point (H). The descending stage (80) includes a first descending stage (81) before the sewing needle (30) enters the rotary hook (110), and a second descending stage (82) after the sewing needle (30) enters the rotary hook (110). The ascending stage (90) includes a thread hooking stage (91), a thread hooking point (92), and a rising and resetting stage (93). S3, the sewing machine starts sewing; S4, the needle bar (20) drives the machine needle (30) to move downward, and the machine needle (30) first completes the first downward stage (81); thereafter, the machine needle (30) enters the second downward stage (82), and the electronic control unit controls the telescopic drive source (40) to move, and the telescopic drive source (40) drives the machine needle (30) to move downward a preset distance relative to the needle bar (20); The needle bar (20) drives the machine needle (30) to continue to move downward until the machine needle (30) moves downward to the lowest point (L), and the machine needle (30) completes the second downward stage (82); S5, the needle bar (20) drives the machine needle (30) to move upward, the machine needle (30) first enters the thread hooking stage (91), the electronic control unit controls the telescopic drive source (40) to reset, the telescopic drive source (40) drives the machine needle (30) to move upward relative to the needle bar (20), and the machine needle (30) is reset; The needle bar (20) drives the needle (30) to continue to move upward, and the needle (30) moves upward to the thread hooking point (92). At this time, the hook tip of the rotary hook (110) hooks the thread loop formed at the lower end of the needle (30); The needle bar (20) drives the machine needle (30) to continue to move upward until the machine needle (30) moves upward to the highest point (H), and the machine needle (30) completes the rising and resetting stage (93); S6. Repeat steps S4 and S5 until sewing is completed.

2. The sewing machine anti-stitch skipping control method according to claim 1, characterized in that: The needle rod (20) is provided with an installation inner cavity (22) communicating with the through hole (21), and the telescopic driving source (40) is a bidirectional electromagnet fixed at the lower end of the installation inner cavity (22), and the iron core of the bidirectional electromagnet is connected to the machine needle (30).

3. The sewing machine anti-stitch skipping control method according to claim 1, characterized in that: The needle rod (20) is provided with an installation inner cavity (22) communicating with the through hole (21); the telescopic driving source (40) is a one-way electromagnet fixed to the lower end of the installation inner cavity (22); a return spring is sleeved on the iron core of the one-way electromagnet; and the iron core of the one-way electromagnet is connected to the machine needle (30).

4. The sewing machine anti-stitch skipping control method according to claim 2 or 3, characterized in that: The sewing machine is further provided with a bushing (50) fixed in the housing (10), a conductive strip (60) fixed in the bushing (50), a conductive contact (70) fixed in the needle bar (20), and a connecting circuit. The needle bar (20) is arranged in the bushing (50) so as to be movable up and down. The electric control unit is connected to the conductive strip (60) via the connecting circuit. The conductive strip (60) contacts and cooperates with the conductive contact (70). The conductive contact (70) is connected to a telescopic drive source (40).

5. The sewing machine anti-stitch skipping control method according to claim 4, characterized in that: The conductive strip (60) is linear and extends straight up and down along the moving direction of the needle rod (20). The conductive strip (60) is fixed on the inner wall surface of the bushing (50).

6. The sewing machine anti-stitch skipping control method according to claim 4, characterized in that: The conductive strip (60) is annular and fixed on the inner wall surface of the bushing (50).

7. The sewing machine anti-stitch skipping control method according to claim 4, characterized in that: The conductive contact (70) is cylindrical and extends straight along the radial direction of the needle rod (20).

8. The sewing machine anti-stitch skipping control method according to claim 4, characterized in that: The conductive contact (70) is annular and fixed on the outer wall surface of the needle rod (20).

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