Sewing control method of computer sewing machine

Abstract

The invention provides a sewing control method of a computer sewing machine, and belongs to the technical field of sewing machines. The problem that an existing computer sewing machine is insufficient in sewing quality is solved. The sewing control method comprises the following steps that A, a thread shifting device with a thread shifting rod is arranged on the side portion of a bottom shuttle; b, the control system judges and records a reverse stitch needle point; c, sewing a first needle; d, the feeding device drives the sewing material to move to a next-needle sewing position, and according to whether the needle point of the current sewing position is a reverse stitch needle point or not, the following actions are executed: if yes, a thread shifting rod is controlled to move and act on a bottom thread between a bottom shuttle and a needle plate, so that one part of the bottom thread crosses an axial lead where a machine needle is located, and the other part of the bottom thread crosses an axial lead where the machine needle is located; then the machine needle brings the upper thread to the position below the needle plate, the thread shifting rod is separated from the bottom thread, and the upper thread and the bottom thread are interwoven to form a stitch; if not, the machine needle moves downwards to bring the upper thread to the position below the needle plate, and the upper thread and the bottom thread are interwoven to form a stitch. The sewing machine has the advantages of high sewing quality and low manufacturing cost.

Description

Technical Field

[0001] The invention belongs to the technical field of sewing machines and relates to a sewing control method of a computer sewing machine. Background Art

[0002] As an indispensable equipment in the sewing industry such as clothing manufacturing, sewing machines have a history of hundreds of years. With the continuous development of industrial technology and the intensification of market competition, the clothing industry and other industries have put forward higher requirements for the automation, intelligence and efficiency of sewing equipment. In this context, computerized sewing machines such as template machines and pattern machines came into being.

[0003] The computer sewing machine is a product that combines traditional sewing technology with modern numerical control technology and automatic control technology. It mainly includes a base with a work surface, a machine head, a rotary hook, etc. The machine head is provided with a needle bar mechanism, and the work surface is provided with a feeding device for fixing the sewing material and driving the sewing material to move. When sewing, first input the sewing pattern into the computer sewing machine. After the sewing pattern is input, the numerical control system of the computer sewing machine will generate the needle point trajectory and the motion trajectory of the feeding device according to the pattern. After sewing starts, the feeding device will move along the motion trajectory with the sewing material, and the needle bar mechanism will drive the machine needle to perform the needle action at each needle point of the needle point trajectory, and cooperate with the rotary hook to interweave the upper thread and the lower thread, thereby realizing the sewing of the sewing material.

[0004] In traditional computer sewing, the orientation of the machine head and the bottom shuttle system is fixed, that is, the machine head and the bottom shuttle system do not rotate with the change of the cloth feeding direction. When this type of computer sewing machine is used to sew patterns, the sewing material will move horizontally in different directions with the feeding device, which will cause some of the stitches on the final sewing material to be like this: Figure 5 The positive trace (301 trace) shown, some are as follows Figure 6 The reverse stitch (319 stitch) shown. Since the forward stitch can usually ensure the beauty and consistency of sewing, in the occasions where the sewing quality is required to be high, such as sewing some high-end clothing and leather products, only the forward stitch can be used to sew the product. Therefore, in order to ensure the beauty of the product, it is necessary to avoid the reverse stitch on the product, and this type of computer sewing machine obviously cannot meet this demand.

[0005] In order to solve the above technical problems, the conventional technical means to solve the problem is to use a structure in which the machine head and the bottom shuttle system rotate in the sewing direction to avoid the occurrence of reverse stitches. For example, a template sewing machine with a machine head that can rotate and lift freely is disclosed in a Chinese patent document (authorization announcement number: CN207582086U), in which the upper machine head and the bottom line mechanism are synchronously rotated by a rotating motor arranged inside the machine head assembly through a synchronous belt, and a lifting mechanism for driving the upper machine head to lift and lower is also arranged between the upper machine head and the machine head assembly. The device can rotate in the feeding direction through the upper machine head and the bottom line mechanism, ensuring that the needle bar and the rotary shuttle can automatically adjust the direction according to the direction of the sewing pattern, thereby effectively avoiding the occurrence of reverse stitches.

[0006] Similar sewing machines, such as a template machine head with a rotatable needle bar (publication number: CN210368223U), a 360° infinitely rotatable head template machine (publication number: CN215051188U), and a head rotating template machine and sewing machine (publication number: CN221681367U) disclosed in Chinese patent documents, also use a structure in which the head and bottom shuttle system rotate in the sewing direction to avoid the appearance of reverse stitches during sewing. However, although this type of computer sewing solves the technical problem of ensuring uniform stitches, it still has the following shortcomings:

[0007] 1. The machine head and bottom shuttle system of the computer sewing machine rotate with the cloth feeding direction, which leads to a complex mechanism and high precision requirements. The complex mechanical structure is prone to cumulative errors, which leads to the phenomenon of rotation angle deviation or rotation synchronization deviation of the machine head and bottom shuttle system, thereby affecting the sewing accuracy and causing problems such as uneven stitches or skipped stitches. Therefore, the existing computer sewing machines still have problems with sewing quality and sewing aesthetics.

[0008] 2. The machine head and bottom shuttle system rotate in the direction of sewing, which requires the addition of corresponding drive structure and transmission structure, and the mechanical structure of the machine head and bottom shuttle system will be more complicated, which will lead to an increase in the number of parts of the computer sewing machine and a higher manufacturing cost of the computer sewing machine.

[0009] At present, in order to solve the problem of poor sewing quality caused by the rotation of the machine head and the bottom shuttle system following the sewing direction, the conventional technical means used by those skilled in the art are:

[0010] 1. In terms of manufacturing technology, high-precision processing technology is used to manufacture key components to improve the assembly accuracy and operation accuracy of the sewing mechanism, reduce error accumulation, and improve sewing quality.

[0011] 2. By optimizing the control algorithm, the synchronization between the machine head and the rotary hook can be improved and the error can be reduced.

[0012] 3. Use synchronous belt or synchronous gear transmission to ensure that the machine head and bottom shuttle system can rotate synchronously when the sewing direction changes, reduce the deviation of the rotation angle and improve the sewing quality. Summary of the invention

[0013] The purpose of the present invention is to solve the above problems in the existing technology and propose a control method for a computer sewing machine. The present invention can avoid the occurrence of reverse stitches during the sewing process and solve the problem of insufficient sewing quality of the existing computer sewing machine.

[0014] The object of the present invention can be achieved by the following technical solutions: a sewing control method of a computer sewing machine, the computer sewing machine comprises a bottom shuttle with a shuttle tip, a needle plate with a needle drop hole and a feeding device for fixing the sewing material and driving the sewing material to move, the bottom shuttle has a thread outlet for the bottom thread to pass through, characterized in that the plane where the axis of the bottom shuttle and the sewing machine needle coexist is the critical surface A, the line connecting the thread outlet and the needle drop hole is inclined and the vertical plane where the line is located is the critical surface B, when the shuttle tip of the bottom shuttle moves to the needle, the area between the side of the critical surface A facing away from the thread outlet and the side of the critical surface B facing away from the shuttle tip is the reverse stitch area a, and the sewing control method comprises the following steps:

[0015] A. A thread puller with a thread puller rod is arranged on the side of the bottom shuttle;

[0016] B. The control system generates a needle point trajectory and a motion trajectory of the feeding device according to the sewing pattern, and determines whether the feeding device moves to the reverse stitch area a after each stitch is completed. If so, the needle point corresponding to the next stitch is determined as the reverse stitch needle point and recorded;

[0017] C. The sewing machine starts working and sews the first stitch;

[0018] D. The feeding device drives the sewing material to move to the next stitch position according to the motion trajectory, and performs the following actions according to whether the needle point at the current sewing position is the reverse stitch needle point recorded in the control system:

[0019] If so, the control system controls the thread pusher to move and act on the bottom thread between the bottom shuttle and the needle plate, so that a part of the bottom thread crosses the axis line where the needle is located, and then the needle brings the upper thread to the bottom of the needle plate, the thread pusher is separated from the bottom thread, and the bottom shuttle interweaves the upper thread and the bottom thread to form a stitch;

[0020] If not, the needle moves down to bring the upper thread to the bottom of the needle plate, and the bottom shuttle interweaves the upper thread with the bottom thread to form a stitch;

[0021] E. Repeat step D and follow the needle point trajectory obtained from the sewing pattern for subsequent sewing.

[0022] The needle point trajectory refers to the trajectory of the continuous puncture points formed by the needle on the sewing material during the sewing process. Simply put, it is the route that the needle "walks" on the sewing material, and the distance between two adjacent needle points is the needle length. The area between the side of the critical surface A facing away from the thread outlet and the side of the critical surface B facing away from the shuttle tip is the reverse stitch area a, and the remaining area is the forward stitch area b. For a certain or the same model of computer sewing machine, since the structure (including the type of bottom shuttle, installation position, thread hook direction, thread outlet position, and needle position) is determined, its critical surface A and critical surface B are determined. At the same time, the reverse stitch area a and the forward stitch area b are also determined.

[0023] During the operation of this computer sewing machine, when running step D, when the needle point at the sewing position is not the reverse stitch needle point recorded in the control system, the thread puller does not need to change the position of the bottom thread between the bottom shuttle and the needle plate. At this time, after the needle is lowered, the bottom shuttle is used to interweave the upper thread and the bottom thread, and the needle moves up to tighten the upper thread and the bottom thread on the sewing material to form a forward stitch.

[0024] When the needle point at the sewing position is the reverse stitch needle point recorded in the control system, if the thread shifter is not used to change the position of the bottom line between the bottom shuttle and the needle plate, the needle will be directly inserted normally, and a reverse stitch will be formed. The reason is that after the bottom shuttle expands the upper thread loop and puts it on the bottom line, the needle needs to move up. During this process, the upper thread on the needle will pass between the bottom line and the upper thread on the fabric and tighten upwards. Finally, the upper thread and the bottom line are intertwined to form a "knot", that is, a reverse stitch is formed.

[0025] In the present control method, since the step of changing the position of the bottom line by the thread shifter is added in step D, before the needle is lowered, the thread shifter can first move and act on the bottom line between the bottom shuttle and the needle plate, so that a part of the bottom line crosses the axis line where the needle is located, and then the needle can lower the needle. When the needle moves down to bring the upper thread under the needle plate, the thread shifter is separated from the bottom line. At this time, the bottom line can no longer be reset to the initial position due to the obstruction of the needle. As the upper thread moves up to be tightened, the bottom line and the upper thread on the fabric are located on the same side of the upper thread on the needle. In this way, the upper thread on the needle no longer passes between the bottom line and the upper thread on the fabric to be tightened, thereby avoiding the situation where the upper thread and the bottom line are "knotted", and finally forming a positive stitch with beautiful stitches. In addition, the action of the thread shifter being separated from the bottom line allows the bottom shuttle to expand the upper thread loop, and will not be interfered by the thread shifter in the process of being put on the bottom line.

[0026] Therefore, this computer sewing machine effectively avoids the generation of reverse stitches during sewing by adding a thread shifter with a "stitch conversion" function. In addition, this design only needs to cooperate with the needle's lowering action to control the thread shifter to move back and forth above the bottom shuttle, without the need for the machine head and the bottom shuttle to rotate with the sewing direction, thereby eliminating the problem of reduced sewing quality caused by the deviation of the rotation angle or synchronization of the machine head and the bottom shuttle. Therefore, the design of this computer sewing machine not only reduces the control difficulty, but also significantly reduces sewing errors, further improving sewing quality.

[0027] In the control method of the computerized sewing machine, the bottom shuttle can be a vertical shuttle, a horizontal shuttle and a swing shuttle. The vertical shuttle is a rotary shuttle with a horizontal axis, including a vertical shuttle with a shuttle tip hooking the thread behind the needle and a vertical shuttle with a shuttle tip hooking the thread in front of the needle. The horizontal shuttle is a rotary shuttle with a vertical axis.

[0028] In the above-mentioned sewing control method of the computer sewing machine, the axis of the bottom shuttle is horizontally arranged along the front-back direction of the sewing machine, and the thread-shifting rod has a thread-shifting end. In the step D, if the needle point at the sewing position is a reverse stitch needle point, the actions performed are specifically:

[0029] The control system controls the movement of the thread shifting rod of the thread shifter, so that the thread shifting end of the thread shifting rod moves from the front and lower part of the needle drop hole to the rear and lower part, and pushes the bottom thread between the bottom shuttle and the needle plate during the movement, so that part of the bottom thread crosses the axis line where the needle is located. Then the needle brings the upper thread to the bottom of the needle plate, the thread shifting rod separates from the bottom thread, the needle continues to move down to the lowest point and then moves up, and the tip of the bottom shuttle moves to the back side of the needle to hook the upper thread on the needle, interweaving the upper thread and the bottom thread to form a stitch.

[0030] For the bottom thread between the bottom shuttle and the needle plate, its lower end is located at the thread outlet of the bottom shuttle, and the upper end is located at the needle hole on the needle plate. Therefore, for the bottom shuttle whose shuttle tip hooks the thread at the rear side of the needle, when the thread shifting end of the thread shifting rod moves from the front lower part to the rear lower part of the needle hole, it can rely on the rear side surface of the thread shifting end to accurately and stably push the bottom thread between the bottom shuttle and the needle plate, and when the thread shifting end reaches the rear lower part of the needle hole, it can ensure that the part of the bottom thread in contact with the thread shifting end crosses the axis line where the needle is located and reaches the positive stitch area b, thereby stably and reliably realizing the stitch conversion, and ultimately achieving the purpose of improving sewing quality and sewing aesthetics.

[0031] In the above-mentioned sewing control method of the computer sewing machine, the axis of the bottom shuttle is horizontally arranged along the front-back direction of the sewing machine, and the thread-shifting rod has a thread-shifting end. In the step D, if the needle point at the sewing position is a reverse stitch needle, the specific actions performed are:

[0032] The control system controls the movement of the thread shifting rod of the thread shifter, so that the thread shifting end of the thread shifting rod moves from the rear and lower part of the needle drop hole to the front and lower part, and pushes the bottom thread between the bottom shuttle and the needle plate during the movement, so that part of the bottom thread crosses the axis line where the needle is located. Then the needle brings the upper thread to the bottom of the needle plate, and the thread shifting rod separates from the bottom thread. The needle continues to move down to the lowest point and then moves up. The tip of the bottom shuttle moves to the front side of the needle to hook the upper thread on the needle, and the upper thread and the bottom thread are interwoven to form a stitch.

[0033] A similar principle applies to the bottom shuttle whose shuttle tip hooks the thread on the front side of the needle. When the thread shifting end of the thread shifting rod moves from the rear lower part to the front lower part of the needle drop hole, the front side of the thread shifting end can push the bottom thread between the bottom shuttle and the needle plate. When the thread shifting end reaches the front lower part of the needle drop hole, the part of the bottom thread in contact with the thread shifting end can cross the axis line of the needle and reach the positive stitch area b, thereby stably and reliably realizing the stitch conversion, and ultimately achieving the purpose of improving the sewing quality and sewing aesthetics.

[0034] In the sewing control method of the above-mentioned computer sewing machine, in step D, the way in which the thread shifting rod is separated from the bottom line is specifically as follows: the thread shifting rod continues to move so that its thread shifting end starts from the rear and lower part of the needle drop hole, moves in the left and right directions to move away from the bottom shuttle, and separates from the bottom line after moving a certain distance.

[0035] When the thread-pushing end of the thread-pushing lever moves to the rear lower part of the needle drop hole, the bottom line between the bottom shuttle and the needle plate will still be against the rear side of the thread-pushing end, waiting for the needle to be lowered. When the needle moves down to the lower part of the needle plate, the thread-pushing end moves left and right, causing the thread-pushing lever to gradually move away from the bottom shuttle, and eventually the bottom line will be detached from the thread-pushing end of the thread-pushing lever. At this time, the movement of the needle and the bottom shuttle is no longer disturbed by the thread-pushing lever, making the process of hooking the thread and forming the stitch more stable.

[0036] In the sewing control method of the computer sewing machine described above, in step D, during the process of the needle moving from the lowest point to the highest point, the thread-shifting end of the thread-shifting lever returns to the front lower part of the needle drop hole.

[0037] When the thread shifting lever performs the thread shifting action, its starting point is located in the front and lower part of the needle drop hole. Therefore, in the process of the needle moving up to the highest point, the thread shifting lever moves synchronously to make the thread shifting end of the thread shifting lever return to the front and lower part of the needle drop hole. This design allows the thread shifting lever to immediately perform the thread shifting action without the need for additional left and right movements when the thread needs to be shifted again, thereby shortening the preparation time for the thread shifting process. In this way, the sewing efficiency can be greatly improved in the sewing process that requires continuous thread shifting.

[0038] In the sewing control method of the computer sewing machine described above, in the step D, if the needle point of the current sewing position is not the reverse stitch needle point recorded in the control system, the thread spreader is in a stationary waiting state.

[0039] During the sewing process of a computer sewing machine, the frequency of forming forward stitches is generally much higher than that of reverse stitches. Therefore, when forming forward stitches, keeping the thread puller in a stationary waiting state can reduce the movement frequency of the thread puller, thereby reducing the wear of the thread puller and extending its service life.

[0040] In the sewing control method of the above-mentioned computer sewing machine, in the step B, the needle point trajectory is generated in the following manner: the control system performs image processing on the sewing pattern, converts the contour line of the sewing pattern into a continuous path, establishes needle point coordinates according to the preset needle distance between two needle points, and generates a continuous needle point trajectory according to the needle point coordinates.

[0041] The needle point coordinates generated based on the preset stitch length ensure the accuracy and consistency of the needle point trajectory, reducing human errors, especially when performing some complex sewing patterns, such as embroidery, decorative sewing, etc., which can significantly improve the sewing quality.

[0042] In the above-mentioned sewing control method of the computer sewing machine, in the step B, the motion trajectory of the feeding device is generated in the following way: the displacement vector of the feeding device is calculated according to the needle point trajectory and the origin position of the feeding device, and the displacement vector is converted into the motion trajectory of the feeding device.

[0043] The calculation of the displacement vector is based on the needle point trajectory and the origin position of the feeding device, which avoids the deviation caused by mechanical error or human operation in the traditional feeding method and reduces the sewing error. By calculating the displacement vector of the feeding device, the movement of the feeding device can be accurately controlled to ensure that the needle point of each needle is completely matched with the needle point trajectory, thereby improving the sewing accuracy and sewing quality, making the sewing stitches uniform and beautiful.

[0044] In the above-mentioned sewing control method of the computer sewing machine, a database of sewing pattern needle point trajectories is established in step B, and the database includes needle point trajectories corresponding to a variety of sewing patterns and motion trajectories of the feeding device corresponding to the needle point trajectories. The corresponding needle point trajectory is determined by selecting the sewing pattern in the database.

[0045] By establishing a needle point trajectory database, users can directly select pre-stored sewing patterns from the database and quickly obtain the corresponding needle point trajectory and feeding device motion trajectory, avoiding the tedious process of repeated programming or manual input, thereby improving sewing efficiency.

[0046] Compared with the prior art, the sewing control method of the computer sewing machine has the following advantages:

[0047] 1. In this computer sewing machine, by adding a thread puller, the thread puller has the function of "stitch conversion", which can avoid the appearance of reverse stitches during sewing, ensure the beauty and consistency of sewing, and make the computer sewing machine well applied to sewing some high-end clothing, leather products and other occasions with high sewing quality requirements.

[0048] 2. This sewing machine only needs to coordinate with the needle's lowering action to control the thread lever to move back and forth above the bottom shuttle, without the need for the machine head and the bottom shuttle to rotate with the sewing direction, thus eliminating the problem of reduced sewing quality caused by the deviation of the rotation angle or synchronization of the machine head and the bottom shuttle. Therefore, the design of this computer sewing machine not only reduces the control difficulty, but also significantly reduces the sewing error, further improving the sewing quality.

[0049] 3. Since in this computer sewing machine, the machine head and the bottom shuttle only need to maintain a constant direction for sewing, the structure of the sewing machine is simplified and the manufacturing cost is significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a top view of the bottom shuttle and the thread-pulling rod in the first embodiment.

[0051] Figure 2 It is a partial structural schematic diagram of the first embodiment of the computerized sewing machine.

[0052] Figure 3 It is an enlarged view of the bottom shuttle part in the first embodiment of the computer sewing machine.

[0053] Figure 4 It is a structural schematic diagram of the dialer in the first embodiment.

[0054] Figure 5 This is a schematic diagram of the forward trace (301 trace).

[0055] Figure 6 This is a schematic diagram of the reverse stitch (319 stitch).

[0056] Figure 7 The sewing process in the first embodiment is shown in FIG. Figure 1 .

[0057] Figure 8 It is a schematic diagram of the principle of forming a reverse trace in the first embodiment.

[0058] Fig. 9 The sewing process in the first embodiment is shown in FIG. Figure 2 .

[0059] Fig.10 It is a schematic diagram of the thread-pushing lever driving the bottom thread to move in the first embodiment.

[0060] Fig.11 Schematic diagram of the trace area of ​​the second embodiment.

[0061] In the figure, 1. bottom shuttle; 11. thread outlet; 12. shuttle tip; 2. needle plate; 21. needle drop hole; 3. thread puller; 31. thread pulley; 32. thread puller rod; 321. thread puller end; 33. guide bracket; 34. drive source; 4. needle; 5. base. DETAILED DESCRIPTION

[0062] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0063] Embodiment 1

[0064] like Figure 1 and Figure 2 As shown, the computer sewing machine includes a base 5, on which are provided a thread spreader 3, a bottom shuttle 1 with a shuttle tip 12, a needle plate 2 with a needle drop hole 21, and a feeding device for fixing the sewing material and driving the sewing material to move. The feeding device is a prior art, not shown in the figure, and a feeding template in a template sewing machine can be used. The bottom shuttle 1 has a thread outlet 11 for the bottom thread to pass through. The plane where the axis of the bottom shuttle 1 and the sewing machine needle 4 coexist is the critical plane A, and the vertical plane where the inclined connection line of the thread outlet 11 and the needle drop hole 21 is located is the critical plane B. When the shuttle tip 12 of the bottom shuttle 1 moves to the needle 4, the area between the side of the critical plane A facing away from the thread outlet 11 and the side of the critical plane B facing away from the shuttle tip 12 is the reverse stitch area a, and the remaining area is the forward stitch area b.

[0065] like Figures 2 to 4 As shown, the bottom shuttle 1 is a vertical shuttle with a shuttle tip 12 hooking the thread behind the needle 4, and the axis of the bottom shuttle 1 is horizontally arranged along the front and rear direction of the sewing machine. The thread puller 3 is arranged on the side of the bottom shuttle 1, and includes a thread puller wheel 31, a thread puller rod 32, a guide bracket 33 and a driving source 34. The driving source 34 is a motor and is arranged vertically. The driving source 34 is fixed on the base 5, and the thread puller wheel 31 is arranged horizontally and is coaxially fixed with the rotating shaft of the driving source 34. The thread puller rod 32 is arranged horizontally, and one end of the thread puller rod 32 is rotatably connected to the eccentric position of the thread puller wheel 31 and can swing horizontally. The other end of the thread puller rod 32 is a thread puller end 321, and the guide bracket 33 is rotatably connected to the base 5. The middle section of the thread puller rod 32 passes through and is supported on the guide bracket 33. When the driving source 34 is working, it drives the thread puller wheel 31 to rotate, so that the thread puller rod 32 performs a comprehensive movement of swinging back and forth and axial reciprocating movement.

[0066] The sewing control method comprises the following steps:

[0067] 1. The control system performs image processing on the sewing pattern, converts the contour line of the sewing pattern into a continuous path, establishes needle point coordinates according to the preset needle distance between two needle points, and generates a continuous needle point trajectory according to the needle point coordinates.

[0068] 2. Calculate the displacement vector of the feeding device according to the needle point trajectory and the origin position of the feeding device, and convert the displacement vector into the motion trajectory of the feeding device.

[0069] 3. The control system determines whether the feeding device moves to the reverse stitch area a after each stitch is completed. If so, the needle point corresponding to the next stitch is determined as the reverse stitch needle point and recorded.

[0070] 4. The sewing machine starts working and sews the first stitch at the starting point in the needle point track.

[0071] 5. The feeding device drives the sewing material to move to the next stitch position according to the motion trajectory, and performs the following actions according to whether the needle point at the current sewing position is the reverse stitch needle point recorded in the control system:

[0072] If so, the driving source 34 is controlled to drive the thread-pushing lever 32 to move, so that the thread-pushing end 321 of the thread-pushing lever 32 moves from the front lower part to the rear lower part of the needle drop hole 21, and pushes the bottom thread between the bottom shuttle 1 and the needle plate 2 during the movement, so that the bottom thread part crosses the axis of the needle 4. After that, the driving source 34 continues to drive the thread-pushing lever 32 to move, so that the thread-pushing end 321 of the thread-pushing lever 32 starts from the rear lower part of the needle drop hole 21, moves in the left and right direction and moves away from the bottom shuttle 1, so that the thread-pushing end 321 is separated from the bottom thread. Subsequently, the needle 4 continues to move down to the lowest point, and then moves up to form an upper thread loop on the needle 4. During the upward movement of the needle 4, the shuttle tip 12 of the bottom shuttle 1 moves to the rear side of the needle 4 to hook the upper thread on the needle, and expand the upper thread loop so that the upper thread loop is wrapped around the bottom thread and interwoven with the bottom thread. When the needle 4 continues to move up to the highest point, the upper thread and the bottom thread are tightened to form a stitch. At the same time, the driving source 34 continues to drive the thread shifting rod 32 to move, so that the thread shifting end 321 of the thread shifting rod 32 returns to the front and lower part of the needle drop hole 21.

[0073] If not, the thread puller 3 is in a stationary waiting state, the needle 4 moves down to bring the upper thread to the lowest point, and then moves up to form an upper thread loop on the needle 4. In the process of the needle 4 moving up, the shuttle tip 12 of the bottom shuttle 1 moves to the back side of the needle 4 to hook the upper thread on the needle, and expand the upper thread loop so that the upper thread loop is wrapped around the bottom thread and intertwined with the bottom thread. When the needle 4 continues to move up to the highest point, the upper thread and the bottom thread are tightened to form a stitch.

[0074] 6. Repeat step 5 and follow the needle point trajectory obtained from the sewing pattern for subsequent sewing.

[0075] The following uses the vertical shuttle with the shuttle tip hooking the thread behind the needle as an example to introduce the working principle of this sewing control method:

[0076] For a certain or the same type of computer sewing machine, since the structure (including the type of the bottom shuttle 1, the installation position, the thread hooking direction, the position of the thread outlet 11, and the position of the needle 4) is determined, its critical surface A and critical surface B are determined, and the reverse stitch area a and the forward stitch area b are also determined. After the needle point trajectory and the motion trajectory of the feeding device are determined, the movement path of the sewing material is determined. At this time, the control system can calculate whether the feeding device moves to the reverse stitch area a after each stitch is completed, and then accurately control the thread shifting timing of the thread shifter 3.

[0077] During the operation of the computerized sewing machine, when the feeding device moves toward the positive stitch area b to feed the material, the needle 4 moves up with the upper thread, and in the process of tightening the upper thread, as shown in FIG. Figure 7 As shown in the figure, the bottom thread between the bottom shuttle 1 and the needle plate 2 and the upper thread on the fabric are both located on the same side of the upper thread on the needle 4, so the thread puller 3 does not need to change the position of the bottom thread between the bottom shuttle 1 and the needle plate 2, and can also form Figure 5 Forward trace (i.e. 301 trace) shown.

[0078] When the needle point at the sewing position is the reverse stitch needle point, the feeding device moves to the reverse stitch area a for feeding. At this time, if the position of the bottom line between the bottom shuttle 1 and the needle plate 2 is not changed by the thread puller 3, the needle 4 is directly lowered normally, and a reverse stitch will be formed at this time. The reason is: Figure 8 As shown in FIG. 1 , after the bottom shuttle 1 expands the upper thread loop and puts it on the bottom thread, the needle 4 needs to move up. During this process, the upper thread on the needle 4 will pass between the bottom thread and the upper thread on the fabric and tighten upwards. Finally, the upper thread and the bottom thread are intertwined to form a "knot", that is, a knot is formed as shown in FIG. Figure 6 Reverse stitch (i.e. 319 stitch) shown.

[0079] In the present control method, since the step of changing the bottom line position of the thread shifter 3 is added in the above step 5, before the needle 4 is lowered, the thread shifter 3 can be moved by the thread shifter 32 and act on the bottom line between the bottom shuttle 1 and the needle plate 2, so that a part of the bottom line crosses the axis line where the needle 4 is located, and then the needle 4 can be lowered. Fig.10 , you can clearly understand the state before and after the thread lever 32 drives the bottom line to move, Fig.10In the figure, the thick solid line T indicates the position of the bottom line between the bottom shuttle 1 and the needle plate 2 when the thread shifting lever 32 does not perform the thread shifting action. The thin solid line t indicates the position of the bottom line between the bottom shuttle 1 and the needle plate 2 after the thread shifting lever 32 performs the thread shifting action. It can be seen from the thin solid line t that a part of the bottom line crosses the axis line where the needle 4 is located. When the needle 4 moves down to bring the upper thread under the needle plate 2, the thread shifting lever 32 is separated from the bottom line. At this time, the bottom line cannot be reset to the initial position due to the obstruction of the needle 4. In this way, the upper thread moves upward with the needle 4 to be tightened. Fig. 9 As shown, the bottom thread and the upper thread on the fabric are both located on the same side of the upper thread on the needle 4, so that the upper thread on the needle 4 is no longer Figure 8 The thread is tightened by passing it between the bottom thread and the upper thread on the fabric to avoid the upper thread and the bottom thread from becoming tangled. Figure 5 Forward trace shown.

[0080] Embodiment 2

[0081] The structure and principle of this embodiment are basically the same as those of the first embodiment, except that the type of the bottom shuttle 1 is different. Fig.11 As shown, the bottom shuttle 1 is a rotary shuttle, the axis line of which is horizontally arranged along the front-rear direction of the sewing machine, and the shuttle tip 12 thereof moves to the front side of the needle 4 to hook the surface thread on the needle 4 .

[0082] Fig.11 The bottom shuttle 1 in the figure is a simplified diagram of a top view. The bottom shuttle 1 has a thread outlet 11 for the bottom thread to pass through. The plane where the axis of the bottom shuttle 1 and the sewing machine needle 4 coexist is the critical plane A, and the vertical plane where the inclined line connecting the thread outlet 11 and the needle drop hole 21 is located is the critical plane B. When the shuttle tip 12 of the bottom shuttle 1 moves to the needle 4, the area between the side of the critical plane A facing away from the thread outlet 11 and the side of the critical plane B facing away from the shuttle tip 12 is the reverse stitch area a, and the remaining area is the forward stitch area b.

[0083] The sewing control method comprises the following steps:

[0084] 1. The control system performs image processing on the sewing pattern, converts the contour line of the sewing pattern into a continuous path, establishes needle point coordinates according to the preset needle distance between two needle points, and generates a continuous needle point trajectory according to the needle point coordinates.

[0085] 2. Calculate the displacement vector of the feeding device according to the needle point trajectory and the origin position of the feeding device, and convert the displacement vector into the motion trajectory of the feeding device.

[0086] 3. The control system determines whether the feeding device moves to the reverse stitch area a after each stitch is completed. If so, the needle point corresponding to the next stitch is determined as the reverse stitch needle point and recorded.

[0087] 4. The sewing machine starts working and sews the first stitch at the starting point in the needle point track.

[0088] 5. The feeding device drives the sewing material to move to the next stitch position according to the motion trajectory, and performs the following actions according to whether the needle point at the current sewing position is the reverse stitch needle point recorded in the control system:

[0089] If so, the control system controls the thread shifting rod 32 of the thread shifting device 3 to move, so that the thread shifting end 321 of the thread shifting rod 32 moves from the rear and lower part to the front and lower part of the needle drop hole 21, and pushes the bottom line between the bottom shuttle 1 and the needle plate 2 during the movement, so that the bottom line part crosses the axis line where the needle 4 is located, and then the needle 4 brings the upper thread to the bottom of the needle plate 2, the thread shifting rod 32 separates from the bottom line, the needle 4 continues to move down to the lowest point and then moves up, and the shuttle tip 12 of the bottom shuttle 1 moves to the front side of the needle 4 to hook the upper thread on the needle 4, and the upper thread and the bottom thread are interwoven to form a stitch.

[0090] If not, the thread puller 3 is in a stationary waiting state, the needle 4 moves down to bring the upper thread to the lowest point, and then moves up to form an upper thread loop on the needle 4. In the process of the needle 4 moving up, the shuttle tip 12 of the bottom shuttle 1 moves to the front side of the needle 4 to hook the upper thread on the needle, and expand the upper thread loop so that the upper thread loop is wrapped around the bottom thread and interwoven with the bottom thread. When the needle 4 continues to move up to the highest point, the upper thread and the bottom thread are tightened to form a stitch.

[0091] 6. Repeat step 5 and follow the needle point trajectory obtained from the sewing pattern for subsequent sewing.

[0092] A similar principle applies to the bottom shuttle 1 whose shuttle tip 12 hooks the thread on the front side of the needle 4. When the thread shifting end 321 of the thread shifting rod 32 moves from the rear lower part to the front lower part of the needle drop hole 21, the bottom thread between the bottom shuttle 1 and the needle plate 2 can be pushed by the front side of the thread shifting end 321. When the thread shifting end 321 reaches the front lower part of the needle drop hole 21, the part of the bottom thread in contact with the thread shifting end 321 can cross the axis line of the needle 4 and reach the positive stitch area b, thereby stably and reliably realizing the stitch conversion, and ultimately achieving the purpose of improving the sewing quality and sewing aesthetics.

[0093] Embodiment 3

[0094] The structure and principle of this embodiment are basically the same as those of the first embodiment, except that: a database of sewing pattern needle point trajectories is established, the database includes needle point trajectories corresponding to a variety of sewing patterns and motion trajectories of a feeding device corresponding to the needle point trajectories, and the corresponding needle point trajectories are determined by selecting a sewing pattern in the database. By establishing a needle point trajectory database, a user can directly select a pre-stored sewing pattern from the database, quickly obtain the corresponding needle point trajectory and motion trajectory of the feeding device, avoiding the tedious process of repeated programming or manual input, thereby improving sewing efficiency.

[0095] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0096] Although this article uses more terms such as 1, bottom shuttle; 11, thread outlet; 2, needle plate; 21, needle drop hole; 3, thread puller; 31, thread puller wheel; 32, thread puller rod; 321, thread puller end; 33, guide bracket; 34, driving source; 4, needle; 5, base, etc., it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A sewing control method for a computer sewing machine, the computer sewing machine comprising a bottom shuttle (1) having a shuttle tip (12), a needle plate (2) having a needle drop hole (21), and a feeding device for fixing sewing materials and driving the sewing materials to move, the bottom shuttle (1) having a thread outlet (11) for the bottom thread to pass through, characterized in that: The plane where the axis of the bottom shuttle (1) and the sewing machine needle (4) coexist is the critical plane A, the line connecting the thread outlet (11) and the needle drop hole (21) is inclined and the vertical plane where the line is located is the critical plane B, when the shuttle tip (12) of the bottom shuttle (1) moves to the needle (4), the area between the side of the critical plane A facing away from the thread outlet (11) and the side of the critical plane B facing away from the shuttle tip (12) is the reverse stitch area a, and the sewing control method comprises the following steps: A. A thread puller (3) having a thread puller rod (32) is provided on the side of the bottom shuttle (1); B. The control system generates a needle point trajectory and a motion trajectory of the feeding device according to the sewing pattern, and determines whether the feeding device moves to the reverse stitch area a after each stitch is completed. If so, the needle point corresponding to the next stitch is determined as the reverse stitch needle point and recorded; C. The sewing machine starts working and sews the first stitch; D. The feeding device drives the sewing material to move to the next stitch position according to the motion trajectory, and performs the following actions according to whether the needle point at the current sewing position is the reverse stitch needle point recorded in the control system: If so, the control system controls the thread pusher (32) of the thread pusher (3) to move and act on the bottom thread between the bottom shuttle (1) and the needle plate (2), so that a portion of the bottom thread crosses the axis line where the needle (4) is located, and then the needle (4) brings the upper thread to the bottom of the needle plate (2), the thread pusher (32) is separated from the bottom thread, and the bottom shuttle (1) interweaves the upper thread and the bottom thread to form a stitch; If not, the needle (4) moves downward to bring the upper thread to the bottom of the needle plate (2), and the bottom shuttle (1) interweaves the upper thread with the bottom thread to form a stitch; E. Repeat step D and follow the needle point trajectory obtained from the sewing pattern for subsequent sewing.

2. The sewing control method of a computer sewing machine according to claim 1, characterized in that: The axis of the bottom shuttle (1) is arranged horizontally along the front-rear direction of the sewing machine, the thread-shifting rod (32) has a thread-shifting end (321), and in step D, if the needle point at the sewing position is a reverse stitch needle point, the actions performed are specifically: The control system controls the movement of the thread shifting rod (32) of the thread shifting device (3), so that the thread shifting end (321) of the thread shifting rod (32) moves from the front lower part of the needle drop hole (21) to the rear lower part, and pushes the bottom line between the bottom shuttle (1) and the needle plate (2) during the movement, so that the bottom line part crosses the axis line where the needle (4) is located, and then the needle (4) brings the upper thread to the lower part of the needle plate (2), and the thread shifting rod (32) is separated from the bottom line, and the needle (4) continues to move down to the lowest point and then moves up, and the shuttle tip (12) of the bottom shuttle (1) moves to the rear side of the needle (4) to hook the upper thread on the needle (4), and the upper thread and the bottom thread are interwoven to form a stitch.

3. The sewing control method of a computer sewing machine according to claim 1, characterized in that: The axis of the bottom shuttle (1) is arranged horizontally along the front-rear direction of the sewing machine, the thread-shifting rod (32) has a thread-shifting end (321), and in step D, if the needle point at the sewing position is a reverse stitch needle, the actions performed are specifically: The control system controls the movement of the thread shifting rod (32) of the thread shifting device (3), so that the thread shifting end (321) of the thread shifting rod (32) moves from the lower rear part of the needle drop hole (21) to the lower front part, and pushes the bottom thread between the bottom shuttle (1) and the needle plate (2) during the movement, so that the bottom thread part crosses the axis line where the needle (4) is located, and then the needle (4) brings the upper thread to the lower part of the needle plate (2), and the thread shifting rod (32) is separated from the bottom thread, and the needle (4) continues to move down to the lowest point and then moves up, and the shuttle tip (12) of the bottom shuttle (1) moves to the front side of the needle (4) to hook the upper thread on the needle (4), and the upper thread and the bottom thread are interwoven to form a stitch.

4. The sewing control method of a computer sewing machine according to claim 2, characterized in that: In step D, the thread-pushing rod (32) is separated from the bottom thread in the following manner: the thread-pushing rod (32) continues to move so that its thread-pushing end (321) starts from the lower rear portion of the needle drop hole (21), moves in the left-right direction to move away from the bottom shuttle (1), and separates from the bottom thread after moving a certain distance.

5. The sewing control method of a computer sewing machine according to claim 4, characterized in that: In the step D, during the process of the needle (4) moving upward from the lowest point to the highest point, the thread-moving end (321) of the thread-moving rod (32) returns to the front lower part of the needle drop hole (21).

6. The sewing control method of a computer sewing machine according to any one of claims 1 to 5, characterized in that: In the step D, if the needle point at the current sewing position is not the reverse stitch needle point recorded in the control system, the thread spreader (3) is in a stationary waiting state.

7. The sewing control method of a computer sewing machine according to any one of claims 1 to 5, characterized in that: In step B, the needle point trajectory is generated in the following manner: the control system performs image processing on the sewing pattern, converts the contour line of the sewing pattern into a continuous path, establishes needle point coordinates according to the preset needle distance between two needle points, and generates a continuous needle point trajectory according to the needle point coordinates.

8. The sewing control method of a computer sewing machine according to any one of claims 1 to 5, characterized in that: In step B, the motion trajectory of the feeding device is generated in the following manner: a displacement vector of the feeding device is calculated according to the needle point trajectory and the origin position of the feeding device, and the displacement vector is converted into the motion trajectory of the feeding device.

9. The sewing control method of a computer sewing machine according to any one of claims 1 to 5, characterized in that: In step B, a database of sewing pattern needle point trajectories is established, which includes needle point trajectories corresponding to a variety of sewing patterns and motion trajectories of feeding devices corresponding to the needle point trajectories. The corresponding needle point trajectory is determined by selecting a sewing pattern in the database.

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