Single-needle-driven double-layer lap joint splicing device and sewing method thereof

Abstract

The invention discloses a single-needle-driven double-layer lap joint splicing device and a sewing method thereof, and belongs to the technical field of textile. The transmission module, the thread picking module and the thread guiding and hooking module are synchronously controlled through the driving module, so that the modules are highly coordinated, and the problems of mesh hooking, stitch disorder and the like caused by synchronous errors of a traditional multi-power source are solved; the staggered distribution design of the thread guiding curved needle and the fixed thread hooking needle is matched with the protruding structure of the needle point of the thread guiding curved needle to assist knocking-over, hooking and pulling damage to regular meshes of the metal mesh can be reduced, and the splicing strength can be guaranteed through the accurate coil sleeving action; and through combination of passive regulation and active regulation, the stability of the splicing quality is remarkably improved. The single-needle-driven double-layer lap joint splicing device is simple in structure, excellent in movement synergy and controllable in tension, and splicing precision, structural integrity and production efficiency are improved.

Description

Technical Field

[0001] This invention belongs to the field of textile technology, specifically relating to a single-sided curved needle single-needle driven sewing device and its sewing method. Background Technology

[0002] Large-size fabrics have a wide range of applications. For example, warp-knitted metal mesh, with its high strength, corrosion resistance, and regular mesh structure, is widely used in protective fences, industrial filters, building reinforcement membranes, and electromagnetic shielding. Since the width of the mesh output from a single warp knitting machine is limited, it needs to be spliced ​​together to form large-size finished products. Therefore, an efficient and reliable sewing mechanism is the core guarantee for the large-scale production of large-size fabrics. Currently, the stitching of large-sized fabrics such as metal mesh mainly relies on traditional hand sewing, modification of traditional textile sewing machines (such as overlock machines and coverstitch machines), or customized special metal sewing equipment. However, both of these solutions are difficult to adapt to the high rigidity of the metal wires, regular mesh openings, and single-sided operation characteristics of warp-knitted metal mesh. Traditional industrial sewing machines have complex structures, integrating modules such as feeding, thread take-up, and multi-needle linkage, which cannot meet the requirements of lightweight equipment and flexible deployment for splicing large metal mesh. In single-sided double-needle equipment, the coordinated movement of the threading needle and hook needle can easily snag on the metal mesh openings, causing damage. At the same time, the thread tension mostly relies on passive adjustment and cannot be precisely controlled according to the characteristics of the mesh, which can easily lead to problems such as loose or overly tight stitches. Existing solutions have significant technological gaps in areas such as lightweight design, hook and loop issues, active tension control, and mesh protection, making it difficult to meet the requirements of warp-knitted metal mesh for stitching accuracy, structural integrity, and production efficiency. Therefore, developing a single-sided looper stitching mechanism that is adapted to the characteristics of metal mesh, has a simplified structure, excellent motion coordination, and controllable tension has become a key issue that urgently needs to be addressed in this field. Summary of the Invention

[0003] This invention proposes a single-needle driven double-layer overlapping stitching device and its stitching method. Through an innovative single-needle driven structure, it solves the problems of complex structure, insufficient lightweight, and easy snagging of mesh in existing stitching equipment for single-sided stitching of warp-knitted metal mesh. By actively adjusting the thread tension through a tension regulator and passively adjusting the thread tension through a thread take-up module, it solves the problem of lagging thread tension control. Furthermore, by adapting the motion trajectory planning to the characteristics of the mesh, it solves the problem of stable operation.

[0004] The specific technical solution of the present invention is as follows: A single-needle driven double-layer overlapping stitching device includes a drive module, a transmission module, and a thread guide and hook module. The thread guide and hook module includes a thread guide bend and a hook needle. The output end of the transmission module is connected to the thread guide bend and controls the thread guide bend to swing within a preset range. The needle tip of the thread guide bend has an arc-shaped protrusion structure. The hook needle is fixedly set on the swing trajectory of the thread guide bend. When the thread guide bend swings to intersect with the hook needle, the protrusion is used to assist the hook needle in completing the thread release action. The thread guide bend swings periodically to complete the sewing operation.

[0005] Furthermore, the transmission module includes a belt drive pulley, which has a first output end and a second output end. The first output end is driven to connect to the line take-up module, and the second output end is driven to connect to the cam crank assembly.

[0006] Furthermore, the line-picking module includes a first gear and a second gear that mesh with each other. The first gear is pivotally connected to a first swing rod, and the second gear is pivotally connected to a second swing rod. The free ends of the first swing rod and the second swing rod are pivotally connected to form a line-picking node, and a line-picking hook is fixedly connected to the line-picking node.

[0007] Furthermore, the cam crank assembly includes a small cam that is drivenly connected to the second output end, the output end of the small cam is drivenly connected to a sliding module, the output end of the sliding module is drivenly connected to a large cam, the output end of the large cam is drivenly connected to a swing wheel, and the swing wheel is fixedly connected to the lead wire bend to drive the lead wire bend to swing periodically.

[0008] Furthermore, the small cam is pivotally connected to a first crank assembly, and the large cam is pivotally connected to a second crank assembly. The free ends of the first crank assembly and the second crank assembly are connected to a slider, which slides within a groove.

[0009] Furthermore, it includes a tension regulator, which includes a wire hole and a tension adjustment assembly. The tension adjustment assembly includes a connecting rod and a spring sleeved on the connecting rod. One end of the spring is connected to a knob, and the other end is connected to a clip assembly.

[0010] Furthermore, it includes a thread frame and a yarn guide. The thread on the thread frame is guided by the yarn guide, and after the tension is adjusted by the thread take-up module and the tension regulator, it is connected to the thread hook module.

[0011] Furthermore, the swing range of the lead wire bend is 0-160°.

[0012] Furthermore, the lead wire bend includes a lead wire hole, and the hook needle includes a needle groove. When the lead wire bend swings to interlock with the hook needle, the lead wire hole is located above the needle groove.

[0013] A sewing method for a single-needle driven double-layer overlapping seam device includes: Step 1: In the initial state, both the guide hook and the hook needle are located above the workpiece to be sewn, with the hook needle being fixed in place; Step 2: The drive module drives the guide needle to swing downward along the preset trajectory and pierce into the workpiece to be sewn. It then makes a circular motion at a predetermined angle below the workpiece, while the hook needle remains in the initial position above the workpiece. Step 3: The guide needle passes through the workpiece from bottom to top from one side of the hook needle, and moves further until the guide hole of the guide needle and the hook needle make interlocking contact. Step 4: After the lead hole of the lead needle and the hook needle make interlocking contact, the lead needle moves in the opposite direction along the original trajectory, while the hook needle hooks the thread to form the first loop.

[0014] Step 5: The guide needle continues to move along the original reverse trajectory, returning to the position above the piece to be sewn.

[0015] Step 6: The piece to be sewn completes the feeding motion through the feeding mechanism, so that the single-needle driven double-layer overlapping splicing device is aligned with the next position to be sewn, ready for the next sewing operation. Step 7: Repeat steps 1 to 3. The lead hole of the lead wire bend and the hook needle will cross and contact each other again. The protrusion at the tip of the lead wire bend will push the first coil formed in step 4 to complete the unwinding action. The coil is wrapped around the inside of the lead wire bend. Step 8: The lead thread bend moves back along the original trajectory to the initial state, and the hook needle hooks the thread again to form a second loop. At the same time, the first loop slides along the lead thread bend to the second loop, realizing the interlocking of the two loops. Step 9: Repeat steps 1 to 8 above until all the seams of the pieces to be sewn are completed.

[0016] The present invention has the following technical effects: The lead-hook module, transmission module, and take-up module of this invention are controlled by the same drive module, which has a compact structure and can significantly reduce the overall size and weight of the equipment, meeting the needs of lightweight and flexible deployment in large warp-knitted metal mesh splicing scenarios. At the same time, the single drive module ensures that the motion parameters of each mechanism (such as the swing angle of the lead-hook bend and the take-up rhythm) are highly coordinated, avoiding problems such as hooking the mesh and disordered stitches caused by synchronization errors in traditional multi-power sources.

[0017] The staggered distribution design of the lead wire bend and the fixed hook needle, combined with the protruding structure of the lead wire bend needle tip to assist in unwinding, can reduce the pulling and damage to the regular mesh of the metal mesh, and ensure the strength of the seam through precise coil looping action.

[0018] The tension regulator actively adjusts the thread tension, while the thread take-up module passively adjusts the thread tension. Through the combination of passive adjustment and active control, the tension requirements can be dynamically adapted according to the wire diameter and mesh density of the metal mesh, effectively avoiding excessively loose or tight stitches and significantly improving the stability of the stitching quality.

[0019] Through the transmission conversion of small cam rotation and large cam swing, the movement trajectory of the lead wire bend can be precisely controlled within the range of 0°-160°, ensuring that it can efficiently complete actions such as piercing, hooking, and looping within a single-sided working space, greatly improving splicing efficiency and automation level. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall transmission circuit in one embodiment of the present invention; Figure 2 This is a schematic diagram of a lead hook module in one embodiment of the present invention; Figure 3 This is a schematic diagram of the transmission circuit of the cam crank assembly in one embodiment of the present invention; Figure 4 This is a schematic diagram of the thread-picking module in one embodiment of the present invention. Figure 5 This is a schematic diagram of a tension regulator in one embodiment of the present invention; Figure 6 This is a front view of a single-needle driven double-layer overlapping seam device in one embodiment of the present invention; Figure 7 This is a side view of a single-needle driven double-layer overlapping seam device in one embodiment of the present invention; Figure 8 This is a schematic diagram of the extreme positions of the lead hook module in one embodiment of the present invention; Figure 9 This is a schematic diagram of the suturing steps in one embodiment of the present invention; Figure 10 This is a schematic diagram of the suture stitches in one embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In this specification, identical components are represented by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, while the terms "bottom surface," "top surface," "inner," and "outer" refer to directions towards or away from a specific component, respectively. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this specification, "multiple" means two or more.

[0023] Example 1 like Figures 1 to 7 As shown, this invention discloses a single-needle driven double-layer overlapping stitching device, including a drive module, a transmission module 704, and a thread hook module 706. The thread hook module 706 includes a thread bend 101 and a hook needle 102. The output end of the transmission module 704 is connected to the thread bend 101 and controls the thread bend 101 to swing within a preset range. The needle tip of the thread bend 101 is provided with an arc-shaped protrusion structure. The hook needle 102 is fixedly set on the swing trajectory of the thread bend 101. When the thread bend 101 swings to the point of intersecting contact with the hook needle 102, the protrusion is used to assist the hook needle 102 in completing the thread unwinding action. The thread bend 101 swings periodically to complete the sewing operation.

[0024] In this embodiment, the drive module includes a servo motor 301 and a reducer 302, which work together to provide power to the entire device.

[0025] The thread guide and hook module 706 includes a thread guide bend 101 and a hook needle 102. The thread guide bend 101 and hook needle 102 are staggered and contact each other when their movement trajectories overlap. The thread guide bend 101 is arc-shaped and has a thread guide hole at its tip for threading. The thread guide bend 101 also has an arc-shaped protrusion at its tip. A swing wheel 103 is pivotally connected to the thread guide bend 101 and is located behind the rotation center of the thread guide bend 101. 03 Connect the transmission module 704, and use the power provided by the drive module to drive the lead thread bend 101 to make periodic swings within the angle range of 0° to 160°; the hook needle 102 is fixed and stationary, and the hook needle 102 has a needle groove at the needle tip. When the lead thread bend 101 moves to interlock with the hook needle 102, the lead thread hole is located above the needle groove. The needle groove is used to hook the sewing thread on the lead thread hole, and the protrusion of the lead thread bend 101 needle tip is used to assist the hook needle 102 in completing the thread unwinding action.

[0026] The transmission module 704 includes a belt drive pulley 303. The output end of the drive module is connected to the belt drive pulley 303. The belt drive pulley 303 is equipped with two tension pulleys 702, which are configured to assist the belt drive pulley 303 in maintaining a tensioned state for stable transmission. The belt drive pulley 303 includes a first output end and a second output end. The first output end is connected to the take-up module 304, and the second output end is connected to the cam crank assembly. The cam crank assembly includes a crank, a slider 403 with a groove 402, a large cam 307, and a small cam 305 that are connected to each other. The second output end of the belt drive pulley 303 is connected to the small cam 305. The output end of the small cam 305 is connected to the sliding module 306 composed of the slider 403 and the groove 402. The output end of the sliding module 306 is connected to the large cam 307. The output end of the large cam 307 is connected to a swing wheel 103. The swing wheel 103 is fixedly connected to the lead wire bend 101 to drive the lead wire bend 101 to swing periodically. In this embodiment, the small cam 305 is driven by a servo motor 301 and a reducer 302 to perform a 360° circular motion. The small cam 305 is pivotally connected to a first crank assembly 401, and the large cam 307 is pivotally connected to a second crank assembly 404. The free ends of the first crank assembly 401 and the second crank assembly 404 are connected to a slider 403, which slides within a groove 402. The circular motion of the small cam 305 is converted into the linear reciprocating motion of the slider 403 along the groove 402 by the first crank assembly 401. The slider 403 drives the large cam 307 to periodically oscillate within an angle range of 0° to 160° via the second crank assembly 404. The oscillation output end of the large cam 307 is connected to a lead wire bend 101 to drive the lead wire bend 101 to achieve an oscillation trajectory at a preset angle.

[0027] The first output end of the belt drive pulley 303 is connected to the thread take-up module 304. The thread take-up module 304 includes a first gear 501 and a second gear 502 that mesh with each other. The first gear 501 is pivotally connected to a first swing rod 503, and the second gear 502 is pivotally connected to a second swing rod 505. The free ends of the first swing rod 503 and the second swing rod 505 are pivotally connected to form a thread take-up node, and a thread take-up hook 504 is fixedly connected to the thread take-up node. The thread take-up hook 504 is configured to move in a figure-eight pattern as the two gears mesh and rotate, thereby passively adjusting the thread tension. Since the first gear 501 is also driven by the servo motor 301 and the reducer 302, the thread take-up module 304 and the cam crank assembly can maintain synchronous movement.

[0028] To further optimize thread tension adjustment, this invention also provides a tension adjuster, which includes a guide hole 604, of which two can be provided, and a tension adjusting assembly disposed between the two guide holes 604. The tension adjusting assembly includes a connecting rod 605 and a spring 602 sleeved on the connecting rod 605. One end of the spring 602 is connected to a knob 601, and the other end is connected to a clamping plate group 603. The clamping plate group 603 is configured to clamp the thread passing through the guide hole 604. The knob 601 can tighten or loosen the spring 602 by rotating, thereby adjusting the clamping pressure of the clamping plate group 603 on the thread to actively regulate the thread tension. The thread take-up module 304 and the tension adjuster together form a tension control module 703, which integrates active and passive adjustment, can dynamically adapt to tension requirements, effectively avoids the stitches being too loose or too tight, and significantly improves the stability of the seam quality.

[0029] The single-needle driven double-layer overlapping stitching device provided by this invention is equipped with multiple thread guides 701, all fixed on the outer shell of the device, for guiding and directing the sewing thread; a thread holder 705 is located on the outer shell of the device for holding the thread spool. All components form a collaborative working system under the unified drive of the servo motor 301 and the reducer 302: the sewing thread on the thread holder 705 is sequentially guided by the thread guides 701, its tension is adjusted by the tension control module 703, and then conveyed to the thread guide hook module 706; the belt drive wheel 303, driven by the servo motor 301 and the reducer 302, maintains stable transmission with the assistance of the tension wheel 702, driving the thread take-up module 304 and the cam crank assembly to move synchronously; the cam crank assembly efficiently converts the rotational motion of the servo motor 301 into the oscillating motion required by the thread guide hook module 706, ensuring that the thread guide bend 101 operates precisely along a preset trajectory, ultimately achieving high-quality stitching of the warp-knitted metal mesh 201. Example 2 This invention provides a sewing method for a single-needle driven double-layer overlapping seam device, such as... Figure 8 , Figure 9 The extreme positions of the lead hook module 706 are shown. Figure a shows the initial state of the lead thread hook module 706: at this time, both the lead thread bend 101 and the hook needle 102 are located above the workpiece to be sewn, and the two needles are in a non-contact state. Figure b shows the double-needle contact state of the lead wire hook module 706: the lead wire bend 101 swings to a specific position under the drive of the swing wheel 103, the lead wire hole of the lead wire bend 101 is above the needle groove of the hook needle 102, and the hook needle 102 is in front and the lead wire bend 101 is in the back. Figure c shows the maximum angle traveled by the lead wire bend 101: this angle is the angle between the axis of the lead wire bend 101 in the initial state (Figure a) and the double needle contact state (Figure b), and its angle value is 160°.

[0030] In this embodiment, metal mesh 201 is used as the piece to be sewn, and the specific sewing method includes: As shown in Figure a. Step 1: In the initial state, both the lead wire bend 101 and the hook needle 102 are located above the metal mesh 201, with the hook needle 102 being fixedly set. As shown in Figure d. Step 2: The servo motor 301 outputs power through the reducer 302, which drives the swing wheel 103 to rotate through the transmission module 704. This causes the lead needle 101 to swing from top to bottom along a preset trajectory and pierce the metal mesh 201. It makes a circular motion at a predetermined angle below the workpiece to be sewn. At this time, the hook needle 102 remains in the initial position above the workpiece to be sewn.

[0031] Step 3: The lead wire bend 101 passes through the metal mesh 201 from bottom to top from one side of the hook needle 102, so that the lead wire hole of the lead wire bend 101 and the hook needle 102 make staggered contact.

[0032] As shown in Figure e, Step 4: After the thread hole of the thread guide 101 and the hook needle 102 make interlocking contact, the thread guide 101 moves in the opposite direction along the original trajectory, while the hook needle 102 hooks the thread to form the first loop.

[0033] As shown in Figure f, Step 5: The lead wire bend 101 continues to move along the original reverse trajectory and returns to the position above the metal mesh 201.

[0034] Step 6: The metal mesh 201 to be sewn is fed by the feeding mechanism, so that the single-needle driven double-layer overlapping splicing device is aligned with the next position to be sewn, in preparation for the next sewing operation. As shown in Figures g and h. Step 7: Repeat steps 1 to 3. The lead hole of the lead wire bend 101 and the hook needle 102 make interlocking contact again. The protrusion at the needle tip of the lead wire bend 101 pushes the first coil formed in step 4 to complete the unwinding action. The coil is wrapped around the inside of the lead wire bend 101.

[0035] As shown in Figure i Step 8: The lead thread bend 101 moves back to the initial state along the original trajectory, and the hook needle 102 hooks the thread again to form a second loop. At the same time, the first loop slides along the lead thread bend 101 to the second loop, realizing the interlocking of the two loops.

[0036] Finally, step 9: Repeat steps 1 to 8 above until all the stitching work on the pieces to be sewn is completed.

[0037] like Figure 10The diagram shown is a schematic of the suture stitches and needle holes 205 in this embodiment. Two parallel suture stitches are formed on the front side of the metal mesh 201, which are formed by the cooperation of the looper stitch 203 and the hook stitch 204. Multiple horizontally parallel back stitches 202 are formed on the back side of the metal mesh 201. By adjusting the motion parameters of the single-needle driven double-layer overlapping splicing device and the feed parameters of the feeding mechanism, the shape and distribution of the front and back stitches 202 of the metal mesh 201 can be adjusted.

[0038] In the embodiments disclosed in this application, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments disclosed in this invention according to the specific circumstances.

[0039] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A single-needle driven double-layer overlapping seam device, characterized in that, The device includes a drive module, a transmission module, and a thread hook module. The thread hook module includes a thread bend and a hook needle. The output end of the transmission module is connected to the thread bend and controls the thread bend to swing within a preset range. The needle tip of the thread bend has an arc-shaped protrusion. The hook needle is fixedly positioned on the swing trajectory of the thread bend. When the thread bend swings to the point of intersecting with the hook needle, the protrusion assists the hook needle in completing the thread unwinding action. The thread bend swings periodically to complete the sewing operation.

2. The single-needle driven double-layer overlapping seam device according to claim 1, characterized in that, The transmission module includes a belt drive pulley, which has a first output end and a second output end. The first output end is driven to connect to the line take-up module, and the second output end is driven to connect to the cam crank assembly.

3. The single-needle driven double-layer overlapping seam device according to claim 2, characterized in that, The line-picking module includes a first gear and a second gear that mesh with each other. The first gear is pivotally connected to a first swing rod, and the second gear is pivotally connected to a second swing rod. The free ends of the first swing rod and the second swing rod are pivotally connected to form a line-picking node, and a line-picking hook is fixedly connected to the line-picking node.

4. The single-needle driven double-layer overlapping seam device according to claim 3, characterized in that, The cam crank assembly includes a small cam that is driven to the second output end. The output end of the small cam is driven to a sliding module. The output end of the sliding module is driven to a large cam. The output end of the large cam is driven to a swing wheel. The swing wheel is fixed to the lead wire bend to drive the lead wire bend to swing periodically.

5. The single-needle driven double-layer overlapping seam device according to claim 4, characterized in that, The small cam is pivotally connected to the first crank assembly, and the large cam is pivotally connected to the second crank assembly. The free ends of the first crank assembly and the second crank assembly are connected to a slider, which slides within a groove.

6. The single-needle driven double-layer overlapping seam device according to claim 5, characterized in that, The device includes a tension regulator, which includes a wire hole and a tension adjustment assembly. The tension adjustment assembly includes a connecting rod and a spring sleeved on the connecting rod. One end of the spring is connected to a knob, and the other end is connected to a clip assembly.

7. The single-needle driven double-layer overlapping seam device according to claim 6, characterized in that, It includes a sewing frame and a yarn guide. The sewing thread on the sewing frame is guided by the yarn guide, and then the tension is adjusted by the thread take-up module and the tension regulator before being connected to the thread hook module.

8. The single-needle driven double-layer overlapping seam device according to claim 1, characterized in that, The swing range of the lead wire bend is 0-160°.

9. The single-needle driven double-layer overlapping seam device according to claim 1, characterized in that, The lead wire bend includes a lead wire hole, and the hook needle includes a needle groove. When the lead wire bend swings to make intersecting contact with the hook needle, the lead wire hole is located above the needle groove.

10. The sewing method of the single-needle driven double-layer overlapping seam device according to any one of claims 1-9, characterized in that, include: Step 1: In the initial state, both the guide hook and the hook needle are located above the workpiece to be sewn, with the hook needle being fixed in place; Step 2: The drive module drives the guide needle to swing downward along the preset trajectory and pierce into the workpiece to be sewn. It then makes a circular motion at a predetermined angle below the workpiece, while the hook needle remains in the initial position above the workpiece. Step 3: The guide needle passes through the workpiece from bottom to top from one side of the hook needle, and moves further until the guide hole of the guide needle and the hook needle make interlocking contact. Step 4: After the thread hole of the thread guide bend makes contact with the hook needle, the thread guide bend moves in the opposite direction along the original trajectory, while the hook needle hooks the thread to form the first loop. Step 5: The guide needle continues to move along the original reverse trajectory, returning to the position above the piece to be sewn; Step 6: The piece to be sewn completes the feeding motion through the feeding mechanism, so that the single-needle driven double-layer overlapping splicing device is aligned with the next position to be sewn, ready for the next sewing operation; Step 7: Repeat steps 1 to 3. The lead hole of the lead wire bend and the hook needle will cross and contact each other again. The protrusion at the tip of the lead wire bend will push the first coil formed in step 4 to complete the unwinding action. The coil is wrapped around the inside of the lead wire bend. Step 8: The lead thread looper moves back to the initial state along the original trajectory, and the hook needle hooks the thread again to form a second loop. At the same time, the first loop slides along the lead thread looper to the second loop, realizing the interlocking of the two loops. Step 9: Repeat steps 1 to 8 above until all the seams of the pieces to be sewn are completed.

Images