Sewing machine

Abstract

The invention provides a sewing machine, and belongs to the technical field of sewing equipment. The problem that an existing sewing machine is insufficient in sewing quality is solved. The sewing machine comprises a base, a needle plate with a needle falling hole, a rotating shuttle located below the needle plate, a thread shifting rod and a rotating piece capable of horizontally rotating, a guide piece located on the side portion of the rotating shuttle and capable of horizontally swinging is arranged on the base, the thread shifting rod comprises a rod body and an arc-strip-shaped thread shifting head, and the rod body is connected to the guide piece in a sliding mode in the axial direction of the rod body. One end of the thread pulling head is fixedly connected to the end, close to the rotating shuttle, of the rod body and bent upwards relative to the rod body, the other end of the rod body is rotationally connected to the position, deviating from the rotating center of the rotating piece, of the rotating piece, and when the rotating piece drives the rod body to move, the other end of the thread pulling head can be located between the needle falling hole and the rotating shuttle. The sewing quality is further improved, and the manufacturing cost is remarkably reduced on the basis.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewing equipment and relates to a sewing machine. Background Art

[0002] As an indispensable equipment in the sewing industry such as garment manufacturing, the sewing machine has a development history of hundreds of years. With the continuous development of industrial technology and the intensification of market competition, the sewing industry such as the garment industry has put forward higher requirements for the automation, intelligence, and high efficiency of sewing equipment. Under this background, computerized sewing machines such as template machines and pattern machines have emerged.

[0003] The computerized 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 workbench surface, a head, a rotary hook, etc. A needle bar mechanism is arranged on the head, and a feeding device for fixing the sewing material and driving the sewing material to move is arranged on the workbench surface. When sewing, first input the sewing pattern into the computerized sewing machine. After the sewing pattern is input, the numerical control system of the computerized sewing machine will generate the needle point trajectory and the movement trajectory of the feeding device according to the pattern. After sewing starts, the feeding device will drive the sewing material to move according to the movement trajectory, and the needle bar mechanism will drive the sewing needle to perform a needle-inserting action at each needle point of the needle point trajectory, and cooperate with the rotary hook to interweave the top thread and the bottom thread, so as to realize the sewing of the sewing material.

[0004] In traditional computerized sewing machines, the orientations of the head and the bottom shuttle system are fixed, that is, the head and the bottom shuttle system do not rotate with the change of the feeding direction. When this type of computerized sewing machine is used to sew a pattern, since the sewing material will move horizontally in different directions with the feeding device, some of the stitch patterns finally formed on the sewing material are like Figure 6 the forward stitch (301 stitch) as shown, and some are like Figure 7 the reverse stitch (319 stitch) as shown. Since the forward stitch can usually ensure the aesthetics and consistency of sewing, in some occasions with high requirements for sewing quality such as sewing high-end clothing and leather products, only the forward stitch can be used to sew the products. Therefore, in order to ensure the aesthetics of the products, it is necessary to avoid the appearance of reverse stitches on the products, and this type of computerized sewing machine obviously cannot meet this requirement.

[0005] To solve the above technical problems, the currently conventional technical solution is to adopt a structure in which the head and the bottom shuttle system rotate along with the sewing direction, so as to avoid the appearance of reverse stitches. For example, a template sewing machine with a rotatable and liftable upper head disclosed in a Chinese patent document (authorization publication number: CN207582086U), in which the upper head and the bobbin mechanism are synchronously rotated by a rotating motor arranged inside the head assembly through a synchronous belt. At the same time, a lifting mechanism for driving the upper head to lift is also arranged between the upper head and the head assembly. This device can rotate along with the feeding direction through the upper head and the bobbin mechanism, ensuring that the needle bar and the rotary hook can automatically adjust the direction according to the trend of the sewing pattern, so as to effectively avoid the appearance 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 rotary template machine and a sewing machine on a sewing machine (publication number: CN221681367U) disclosed in Chinese patent documents, also adopt a structure in which the head and the bottom shuttle system rotate along with the sewing direction to avoid the appearance of reverse stitches during sewing. However, although this type of computerized sewing solves the technical problem of ensuring uniform stitches, there are still the following deficiencies:

[0007] 1. In a computerized sewing machine, the head and the bottom shuttle system rotate along with the feeding direction, resulting in a complex mechanism and high precision requirements. The complex mechanical structure is prone to cumulative errors, leading to phenomena such as angular deviation or rotational synchronization deviation of the head and the bottom shuttle system in the sewing machine, thereby affecting the sewing precision and resulting in problems such as uneven thread stitches or skipped stitches. Therefore, existing computerized sewing machines still have problems with sewing quality and sewing aesthetics.

[0008] 2. The head and the bottom shuttle system rotate along with the sewing direction, which requires adding corresponding drive structures and transmission structures, and the mechanical structure of the head and the bottom shuttle system will also be more complex, resulting in an increase in the parts of the sewing machine and a relatively high manufacturing cost of the sewing machine.

[0009] Currently, to solve the problem of insufficient sewing quality caused by the rotation of the head and the bottom shuttle system along with the sewing direction, the conventional technical solutions adopted by those skilled in the art are:

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

[0011] 2. By optimizing the control algorithm, improve the synchronization of the head and the rotary hook during operation and reduce errors.

[0012] 3. Adopt synchronous belt or synchronous gear drive to ensure that the sewing head and the bobbin 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 object of the present invention is to address the above problems existing in the prior art and propose a sewing machine that can avoid the appearance of reverse stitches during the sewing process and simultaneously solve the problem of insufficient sewing quality of existing sewing machines.

[0014] The object of the present invention can be achieved by the following technical solutions: A sewing machine includes a base, a needle plate having a needle hole, and a rotary hook located below the needle plate. It is characterized in that the sewing machine further includes a thread deflecting rod and a rotatable member that can rotate horizontally. A guiding member that can swing horizontally is provided on the base on the side of the rotary hook. The thread deflecting rod includes a rod body and a thread deflecting head in the shape of an arc strip. The rod body is slidably connected to the guiding member along its axial direction. One end of the thread deflecting head is fixedly connected to one end of the rod body close to the rotary hook and bends upward relative to the rod body. The other end of the rod body is rotatably connected to a position on the rotatable member that deviates from its rotation center. When the rotatable member drives the rod body to move, the other end of the thread deflecting head can be located between the needle hole and the rotary hook.

[0015] For a sewing machine, the space between the rotary hook and the needle plate is very limited. Therefore, how to reasonably design the shape of the thread deflecting rod so that the thread deflecting rod can perform the thread deflecting action between the rotary hook and the needle plate is very crucial. In this sewing machine, the thread deflecting rod includes a rod body and a thread deflecting head in the shape of an arc strip. The rod body structure is beneficial to the installation and guiding of the thread deflecting rod, ensuring good stability during the movement of the thread deflecting rod. The design of the thread deflecting head in the shape of an arc strip not only ensures that it can smoothly move into the narrow space between the needle plate and the rotary hook to perform the thread deflecting action, but also because the thread deflecting head bends upward relative to the rod body, the installation position of the rod body can be lowered, and then the installation position of the guiding member for guiding it can be lowered, avoiding the situation where the guiding member is too close to the sewing tabletop of the base and resulting in the guiding member being unable to be installed or difficult to install.

[0016] When the sewing machine is used to sew pattern designs, the sewing material will move horizontally in different directions with the feeding device. When the sewing machine is sewing forward, the rotatable member can not rotate, and at this time the thread deflecting rod does not perform the thread deflecting action. When the feeding direction of the sewing material changes to make the sewing machine sew in reverse, if the position of the bobbin thread between the rotary hook and the needle plate is not changed by the thread deflecting rod and the sewing needle directly goes down normally, a reverse stitch will be formed at this time. The reason is that after the rotary hook expands the loop of the upper thread and sleeves it on the bobbin thread, the sewing needle needs to move upward. During this process, the upper thread on the sewing needle will pass through between the bobbin thread and the upper thread on the fabric and tighten upward. Eventually, the upper thread and the bobbin thread are intertwined to form a "knot", that is, a reverse stitch is formed.

[0017] In this sewing machine, by adding a thread deflecting rod to the side of the rotary hook, the rod body is axially slidably connected to a guide member that can swing horizontally. At the same time, one end of the rod body close to the rotary hook is connected to a thread deflecting head, and the other end is rotatably connected to a position on the rotating member that is offset from its rotation center. This structure enables the rod body to reciprocate axially and swing simultaneously when the rotating member rotates, causing the thread deflecting head at the end of the rod body to perform a circumferential circular motion. And by controlling the rotation direction of the rotating member, the circumferential circular motion direction of the thread deflecting head can be controlled. At the same time, when the rotating member drives the rod body to move, the other end of the thread deflecting head can be located between the needle dropping hole and the rotary hook. That is to say, during the circumferential circular motion of the thread deflecting head, the other end of the thread deflecting head can pass through the gap between the needle dropping hole and the rotary hook.

[0018] When the sewing machine sews in reverse, the rotating member starts to rotate and drives the rod body to move before the sewing needle penetrates the fabric. When the other end of the thread deflecting head passes through the gap between the needle dropping hole and the rotary hook, it pushes the bobbin thread between the rotary hook and the needle plate, causing a part of the bobbin thread to cross the axis line where the sewing needle is located. Then the sewing needle performs the action of penetrating the fabric. When the sewing needle moves downward to bring the top thread below the needle plate, since the other end of the thread deflecting head does not simply swing back and forth but performs a circumferential circular motion and thus has a stroke of moving toward the side of the rotary hook, the other end of the thread deflecting head can disengage from the bobbin thread after the sewing needle penetrates the fabric. At this time, due to the blockage of the sewing needle, the bobbin thread cannot be reset to its initial position. When the top thread on the sewing needle moves upward to tighten while passing through the fabric, the bobbin thread and the top thread on the fabric are both on the same side of the top thread on the sewing needle. In this way, the top thread on the sewing needle no longer passes through between the bobbin thread and the top thread on the fabric to tighten, thus avoiding the situation of the top thread and the bobbin thread "knotting", and finally forming a beautiful forward stitch. In addition, by the thread deflecting head disengaging from the bobbin thread, the rotary hook can expand the top thread loop without being interfered by the thread deflecting head when sleeving the bobbin thread.

[0019] Therefore, this sewing machine effectively avoids the generation of reverse stitches during the sewing process by adding a thread deflecting rod with a "stitch conversion" function. And this design only needs to cooperate with the action of the sewing needle penetrating the fabric to control the movement of the thread deflecting rod, without the need for the machine head and the rotary hook to rotate with the sewing direction, thus eliminating the problem of reduced sewing quality caused by the deviation of the rotation angle or synchronization deviation of the machine head and the rotary hook. Therefore, the design of this sewing machine not only reduces the control difficulty but also significantly reduces the sewing error, further improving the sewing quality.

[0020] In the above sewing machine, the rod body is straight and horizontally arranged, and the thread deflecting head is formed by bending a metal strip.

[0021] The straight rod-shaped rod body is beneficial to the installation and guidance of the thread-pulling rod, ensuring good stability and high thread-pulling accuracy during the movement of the thread-pulling rod. The thread-pulling head is formed by bending a metal strip, which is not only easy to manufacture, but also has a small diameter, facilitating the thread-pulling action when extending into the narrow space between the needle plate and the rotary hook.

[0022] In the above sewing machine, when the rod body moves to make the other end of the thread-pulling head located between the needle dropping hole and the rotary hook, the thread-pulling head is close to the outer peripheral wall of the rotary hook. When the rod body moves to make the other end of the thread-pulling head located between the needle dropping hole and the rotary hook, the thread-pulling head is close to the outer peripheral wall of the rotary hook, which is beneficial to reducing the occupation of the space near the rotary hook by the thread-pulling head while realizing the thread-pulling function, thus avoiding interference with components such as the thread-cutting part and making the layout more reasonable.

[0023] In the above sewing machine, the base includes a seat body and a motor seat fixedly connected to the outer wall of the seat body. A motor with a vertically arranged rotating shaft is fixedly installed on the motor seat, and the rotating part is a disc-shaped thread-pulling wheel. The rotating part is connected to the rotating shaft of the motor and is concentrically arranged. The motor is fixedly connected to the outer wall of the seat body through the motor seat, which is convenient for the installation and maintenance of the motor and avoids occupying the internal space of the seat body at the same time. The design of using a thread-pulling wheel can not only drive the thread-pulling rod to move axially and swing stably, but also has the advantages of simple structure and small occupied space, thus facilitating the installation of the thread-pulling rod in the limited space inside the seat body.

[0024] In the above sewing machine, the base includes a seat body and a motor seat fixedly connected to the outer wall of the seat body. A motor with a vertically arranged rotating shaft is fixedly installed on the motor seat, and the rotating part is strip-shaped. One end of the rotating part is fixedly connected to the rotating shaft of the motor, and the other end is rotatably connected to the other end of the rod body. The motor is fixedly connected to the outer wall of the seat body through the motor seat, which is convenient for the installation and maintenance of the motor and avoids occupying the internal space of the seat body at the same time. The rotating part is strip-shaped, which is easy to manufacture and has low cost, and can also drive the thread-pulling rod to move axially and reciprocally and swing stably.

[0025] In the above sewing machine, the base further includes a connecting plate. There is a relief opening on the outer wall of the seat body. The connecting plate passes through the relief opening. The outer end of the connecting plate is fixedly connected to the motor seat, and the inner end extends into the inner side of the seat body and is close to the rotary hook. The guiding part is rotatably connected to the inner end of the connecting plate.

[0026] On the basis of the external motor, by setting a relief opening on the seat body and a connecting plate passing through the relief opening and extending into the interior of the seat body, the guiding part is rotatably connected to the inner end of the connecting plate, which can make the guiding part close to the rotary hook, facilitating the provision of stable support and guidance for the end of the rod body close to the rotary hook, preventing the rod body from shifting or shaking during the movement, making the thread-pulling position of the thread-pulling head connected to the rod body accurate, and avoiding the situation of thread-pulling failure caused by action errors.

[0027] In the above sewing machine, a relief cutting surface is provided on the front side of the other end of the thread pulling head. When the rotating member rotates, it can drive the rod body to reciprocate axially and swing back and forth at the same time, and the amplitude of the swing is smaller than the amplitude of the axial movement.

[0028] A relief cutting surface is provided on the front side of the other end of the thread pulling head, so that the other end of the thread pulling head can effectively avoid the sewing needle during movement, preventing collision or interference with the sewing needle. Moreover, the design of the relief cutting surface enables the front and back swing amplitude of the thread pulling rod to be smaller, thus shortening the swing stroke of the rod body. A smaller swing stroke means a faster movement speed and higher efficiency, thereby improving the sewing efficiency of the sewing machine. At the same time, the rod body has a larger axial movement amplitude, which can ensure that the thread pulling head smoothly disengages from the bobbin thread, ensure that the rotary hook can smoothly hook the upper thread, and interweave with the bobbin thread after expanding the upper thread loop, improving the working stability and reliability of the sewing machine.

[0029] In the above sewing machine, a plug hole is provided on the end surface of the rod body close to the rotary hook. One end of the thread pulling head is fitted and inserted into the plug hole, and a locking screw is also screwed on the outer wall of the rod body. The inner end of the locking screw abuts against the thread pulling head. By tightening the locking screw, the thread pulling head can be firmly fixed in the plug hole, preventing the thread pulling head from loosening or shifting during movement. At the same time, this design enables fine adjustment of the position of the thread pulling head, ensuring that the position accuracy of the thread pulling head reaches the optimal state, thereby improving the accuracy of the thread pulling position of the thread pulling rod, avoiding the situation of incomplete thread pulling or thread pulling failure, and ensuring that the thread pulling head does not collide with the sewing needle during movement, making the sewing process more stable and improving the sewing quality as well as the safety and reliability of the operation of the sewing machine.

[0030] In the above sewing machine, the guiding member has a guiding hole, and a guiding sleeve coaxially arranged with it is provided in the guiding hole. The middle section of the rod body slidably passes through the guiding sleeve. This structure can improve the guiding effect of the guiding member, enabling the rod body to move axially stably. At the same time, the guiding sleeve can also form good support for the rod body, preventing the rod body from deforming to produce excessive deflection, thereby ensuring the stability of the thread pulling action of the thread pulling rod and the accuracy of the thread pulling position.

[0031] In the above sewing machine, a slider is integrally formed on the rod body, and a chute parallel to the rod body is provided on the guiding member. The slider is slidably connected in the chute. This structure can, on the basis of guiding the rod body, also form good support for the rod body, preventing the rod body from deforming to produce excessive deflection, thereby ensuring the stability of the thread pulling action of the thread pulling rod and the accuracy of the thread pulling position.

[0032] In the above sewing machine, the thread deflector rod further includes a connecting head, and the other end of the rod body is rotatably connected to the rotating member through the connecting head. The connecting head and the rod body are separately manufactured, which is not only convenient for manufacturing, but also facilitates the rotational connection between the rod body and the rotating member through the setting of the connecting head.

[0033] Compared with the prior art, the sewing machine has the following advantages:

[0034] 1. In this sewing machine, by adding a thread deflector rod, which has the function of "stitch conversion", it can avoid the appearance of reverse stitches during the sewing process, ensuring the aesthetics and consistency of sewing, enabling the computerized sewing machine to be well applied to sewing some high-end clothing, leather products and other occasions with high requirements for sewing quality.

[0035] 2. This sewing machine only needs to cooperate with the downward movement of the sewing needle to control the reciprocating movement of the thread deflector rod above the rotary hook, without the need for the machine head and the rotary hook to rotate along the sewing direction, thus eliminating the problem of reduced sewing quality caused by the deviation of the rotation angle or synchronization deviation of the machine head and the rotary hook. Therefore, the design of this computerized sewing machine not only reduces the control difficulty, but also significantly reduces the sewing error, further improving the sewing quality.

[0036] 3. Since in this computerized sewing machine, the machine head and the rotary hook only need to maintain a constant direction for sewing, the structure of the sewing machine is simplified, and the manufacturing cost is significantly reduced. Description of the Drawings

[0037] Figure 1 is a top view of the rotary hook and the thread deflector rod.

[0038] Figure 2 is a partial structural schematic diagram of this sewing machine.

[0039] Figure 3 is an enlarged view of the rotary hook part of this sewing machine.

[0040] Figure 4 is a partial structural schematic diagram of the sewing machine.

[0041] Figure 5 is a partial cross-sectional view of this thread deflector rod and the guide member.

[0042] Figure 6 is a schematic diagram of the forward stitch (stitch 301).

[0043] Figure 7 is a schematic diagram of the reverse stitch (stitch 319).

[0044] Figure 8 is a schematic diagram of the sewing process Figure 1 .

[0045] Figure 9 is a schematic diagram of the principle of forming a reverse stitch.

[0046] Figure 10 It is a schematic diagram of the sewing process Figure 2 .

[0047] Figure 11 It is a schematic diagram showing the lower thread being moved by the thread deflecting lever

[0048] Figure 12 It is a schematic diagram of the stitch area of the second embodiment

[0049] Figure 13 It is a schematic diagram of the installation structure of the thread deflecting lever in the third embodiment

[0050] In the figure, 1 is the base; 1a is the seat body; 1a1 is the relief opening; 1b is the connecting plate; 1c is the motor base; 2 is the needle plate; 21 is the needle dropping hole; 3 is the rotary hook; 31 is the thread outlet; 32 is the shuttle tip; 4 is the thread deflecting lever; 41 is the lever body; 411 is the insertion hole; 412 is the slider; 42 is the thread deflecting head; 421 is the avoidance section; 43 is the connecting head; 5 is the motor; 6 is the rotating part; 7 is the guiding part; 71 is the guiding hole; 72 is the sliding groove; 8 is the guiding sleeve; 9 is the locking screw; 10 is the sewing needle Detailed implementation manners

[0051] The following are specific embodiments of the present invention and, in conjunction with the accompanying drawings, the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments

[0052] Embodiment 1

[0053] As Figure 1 and Figure 2 shown, this sewing machine includes a base 1, a thread deflecting lever 4, a needle plate 2 having a needle dropping hole 21, a rotary hook 3 located below the needle plate 2, and a rotatable rotating part 6. A feeding device for fixing the sewing material and driving the sewing material to move is provided on the top surface of the base 1. The feeding device is a prior art and is not shown in the figure. The feeding device usually selects a feeding template. A guiding part 7 that can swing horizontally is also provided on the base 1 on the side of the rotary hook 3. Among them, the base 1 includes a seat body 1a, a connecting plate 1b, and a motor base 1c fixedly connected to the outer wall of the seat body 1a. A motor 5 with a vertically arranged rotating shaft is fixedly provided on the motor base 1c. The outer wall of the seat body 1a has a relief opening 1a1. The connecting plate 1b passes through the relief opening 1a1. The outer end of the connecting plate 1b is fixedly connected to the motor base 1c, and the inner end extends into the inside of the seat body 1a and is close to the rotary hook 3. The guiding part 7 is rotatably connected to the inner end of the connecting plate 1b. The rotating part 6 is a disc-shaped thread deflecting wheel. The rotating part 6 is connected to the rotating shaft of the motor 5 and is concentrically arranged

[0054] As Figures 3 to 5As shown in the figure, the thread-pulling rod 4 includes a rod body 41 that is straight and horizontally arranged, a connecting head 43, and a thread-pulling head 42 in the shape of an arc-shaped strip. The rod body 41 is slidably connected to the guide member 7 along the axial direction. One end of the thread-pulling head 42 is fixedly connected to one end of the rod body 41 close to the rotary hook 3 and is bent upward relative to the rod body 41. The other end of the rod body 41 is rotatably connected to a position on the rotating member 6 that is offset from its rotation center. When the rotating member 6 drives the rod body 41 to move, the other end of the thread-pulling head 42 can be located between the needle dropping hole 21 and the rotary hook 3. Specifically, when the rotating member 6 rotates, it can drive the rod body 41 to reciprocate axially and swing simultaneously, so that the thread-pulling head 42 at the end of the rod body 41 performs a circumferential cyclic motion. During the motion, the other end of the thread-pulling head 42 can pass through the gap between the needle dropping hole 21 and the rotary hook 3. Among them, the amplitude of the swing of the rod body 41 is smaller than the amplitude of the axial movement. The motor 5 is preferably a servo motor. By the rotation direction of the motor 5, the circumferential cyclic motion direction of the thread-pulling head 42 can be controlled.

[0055] Further, as Figure 2 and Figure 4 shown, the thread-pulling head 42 is formed by bending a metal strip, and the diameter of the thread-pulling head 42 is smaller than the diameter of the rod body 41. When the rod body 41 moves to make the other end of the thread-pulling head 42 located between the needle dropping hole 21 and the rotary hook 3, the thread-pulling head 42 is close to the outer peripheral wall of the rotary hook 3. Such a design is beneficial to realizing the thread-pulling function while reducing the occupation of the space near the rotary hook 3 by the thread-pulling head 42, thereby avoiding interference with components such as the thread-cutting component, and the layout is more reasonable. Further, a relief cutting surface 421 is provided on the front side of the other end of the thread-pulling head 42. The design of the relief cutting surface 421 enables the other end of the thread-pulling head 42 to effectively avoid the sewing needle 10 during the motion, and avoid collision or interference with the sewing needle 10.

[0056] As Figure 5 shown, the guide member 7 has a guide hole 71, and a guide sleeve 8 coaxially arranged with it is provided in the guide hole 71. The middle section of the rod body 41 is slidably inserted into the guide sleeve 8. A plug hole 411 is opened on the end surface of the rod body 41 close to the rotary hook 3, and one end of the thread-pulling head 42 is inserted into the plug hole 411 in a matching manner. A locking screw 9 is also screwed on the outer wall of the rod body 41, and the inner end of the locking screw 9 abuts against the thread-pulling head 42. This design enables the position of the thread-pulling head 42 to be finely adjusted, ensuring that the position accuracy of the thread-pulling head 42 reaches the best state, thereby improving the accuracy of the thread-pulling position of the thread-pulling rod 4 and avoiding the situation of incomplete thread-pulling or thread-pulling failure.

[0057] The working principle of this sewing machine is briefly described below:

[0058] In this embodiment, the axis line of the rotating hook 3 is horizontally arranged along the front-back direction of the sewing machine. The rotating hook 3 has a hook tip 32 and a thread outlet 31 for the bottom thread to pass through. The hook tip 32 moves to the rear side of the sewing needle 10 to hook the top thread on the sewing needle 10. The plane where the axis line of the rotating hook 3 and the sewing needle 10 are located is the critical plane A. The connection line between the thread outlet 31 and the needle dropping hole 21 is inclined, and the vertical plane where this connection line is located is the critical plane B. When the hook tip 32 of the bottom shuttle moves to the position of the sewing needle 10, the area between the side of the critical plane A facing away from the thread outlet 31 and the side of the critical plane B facing away from the hook tip 32 is the reverse stitch area a, and the remaining area is the forward stitch area b. For a certain sewing machine or sewing machines of the same model, due to the structure (including the type, installation position, thread hooking direction, and position of the thread outlet 31 of the rotating hook 3), and the position of the sewing needle 10 being determined, its critical plane A and critical plane B are determined. At the same time, the reverse stitch area a and the forward stitch area b are also determined.

[0059] During the actual sewing process of this sewing machine, it can be carried out according to the following steps:

[0060] 1. The control system generates the needle point trajectory and the movement trajectory of the feeding device according to the sewing pattern, and judges whether the feeding device moves to the reverse stitch area a after each stitch is sewn. If so, it determines the needle point corresponding to the next stitch as a reverse stitch needle point and records it.

[0061] 2. The sewing machine starts to work and sews the first stitch.

[0062] 3. The feeding device drives the sewing material to move to the next stitch sewing position according to the movement trajectory. According to whether the needle point at the current sewing position is the reverse stitch needle point recorded in the control system, the following actions are performed:

[0063] If so, the control system controls the thread shifting lever 4 to move, so that the other end of the thread shifting head 42 moves from the front lower side of the needle dropping hole 21 to the rear lower side, and during the movement, it pushes the bottom thread between the rotating hook 3 and the needle plate 2, so that part of the bottom thread crosses the axis line where the sewing needle 10 is located. Then, the motor 5 continues to drive the thread shifting lever 4 to act, so that the other end of its thread shifting head 42 starts from the rear lower side of the needle dropping hole 21, moves leftward and away from the rotating hook 3, so that the other end of the thread shifting head 42 disengages from the bottom thread. Subsequently, the sewing needle 10 continues to move downward to the lowest point, and then moves upward to form a top thread loop on the sewing needle 10. During the upward movement of the sewing needle 10, the hook tip 32 of the rotating hook 3 hooks the top thread on the sewing needle 10 from the rear side of the sewing needle 10 and expands the top thread loop, so that the top thread loop is sleeved on the bottom thread and intertwined with the bottom thread. When the sewing needle 10 moves upward to the highest point, the top thread and the bottom thread are tightened to form a stitch. At the same time, the motor 5 continues to drive the thread shifting lever 4 to act, so that the other end of its thread shifting head 42 returns to the front lower side of the needle dropping hole 21.

[0064] If not, the thread pulling lever 4 can be in a stationary waiting state, and the sewing machine sews normally.

[0065] 4. Repeat step 3 and perform subsequent sewing according to the needle point trajectory obtained from the sewing pattern.

[0066] Furthermore, in step 3 above, when the needle point at the current sewing position is not the reverse stitch needle point recorded in the control system, the thread pulling lever 4 can also continuously perform the thread pulling action. At this time, when the other end of the thread pulling head 42 moves from the front lower side to the rear lower side of the needle dropping hole 21, even if it pushes against the bobbin thread, it will not cause the bobbin thread to cross the axis line where the sewing needle 10 is located. Therefore, in this case, whether the thread pulling lever 4 performs the above thread pulling action or is in a stationary waiting state, it is essentially the same, and a forward stitch will be formed.

[0067] During the working process of this sewing machine, when running step 3 above, when the needle point at the current sewing position is not the reverse stitch needle point recorded in the control system, the feeding device moves towards the forward stitch area b for feeding, and the sewing machine is in the normal sewing state. At this time, as the sewing needle 10 moves upward with the top thread, during the process of tightening the top thread, as Figure 8 shown, both the bobbin thread between the rotary hook 3 and the needle plate 2 and the top thread on the fabric are on the same side of the top thread on the sewing needle 10. Therefore, the thread pulling lever 4 does not need to change the position of the bobbin thread between the rotary hook 3 and the needle plate 2, and can also form Figure 6 the forward stitch (i.e., the 301 stitch) as shown.

[0068] When the needle point at the current sewing position is the reverse stitch needle point recorded in the control system, the feeding device moves towards the reverse stitch area a for feeding, and the sewing machine is in the reverse sewing state. At this time, if the position of the bobbin thread between the rotary hook 3 and the needle plate 2 is not changed through the thread pulling lever 4, and the sewing needle 10 directly needles normally, a reverse stitch will be formed at this time. The reason is that as Figure 9 shown, after the rotary hook 3 expands the top thread loop and slews it over the bobbin thread, the sewing needle 10 needs to move upward. During this process, the top thread on the sewing needle 10 will pass through between the bobbin thread and the top thread on the fabric and tighten upward. Finally, the top thread and the bobbin thread are intertwined to form a "knot", that is, the reverse stitch (i.e., the 319 stitch) as shown in Figure 7 is formed.

[0069] In this sewing machine, since the step of changing the position of the bobbin thread by the thread pulling lever 4 is added in step 3, before the sewing needle 10 needles, the thread pulling lever 4 can first move and act on the bobbin thread between the rotary hook 3 and the needle plate 2 to make a part of the bobbin thread cross the axis line where the sewing needle 10 is located, and then the sewing needle 10 performs the needling action. Referring to Figure 11 it is possible to clearly understand the front and back states of the thread pulling lever 4 driving the bobbin thread to move. Figure 11In the figure, the thick solid line T indicates the position of the bottom line between the hook 3 and the needle plate 2 when the thread lever 4 does not perform the thread shifting action, and the thin solid line t indicates the position of the bottom line between the hook 3 and the needle plate 2 after the thread lever 4 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 of the needle 10. When the needle 10 moves downward to bring the upper thread under the needle plate 2, the thread shifting head 42 of the thread lever 4 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 10. In this way, the upper thread moves upward with the needle 10 to be tightened, as shown in FIG. Figure 10 As shown, the bottom line and the upper line on the fabric are both located on the same side of the upper line on the needle 10, so that the upper line on the needle 10 is no longer Figure 9 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 6 Forward trace shown.

[0070] Embodiment 2

[0071] The structure and principle of this embodiment are basically the same as those of the first embodiment, except that the type of the rotary hook 3 is different. Figure 12 , the axis of the rotary hook 3 is horizontally arranged along the front-back direction of the sewing machine, the rotary hook 3 has a hook tip 32 and a thread outlet 31 for the bottom thread to pass through, and the hook tip 32 moves to the front side of the needle 10 to hook the upper thread on the needle 10. The plane where the axis of the rotary hook 3 and the needle 10 coexist is the critical plane A, the line connecting the thread outlet 31 and the needle drop hole 21 is inclined and the vertical plane where the line is located is the critical plane B, when the hook tip 32 of the bottom shuttle moves to the needle 10, the area between the side of the critical plane A facing away from the thread outlet 31 and the side of the critical plane B facing away from the hook tip 32 is the reverse stitch area a, and the remaining area is the forward stitch area b.

[0072] The actual sewing process of this sewing machine can be carried out according to the following steps:

[0073] 1. 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;

[0074] 2. The sewing machine starts working and sews the first stitch;

[0075] 3. 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:

[0076] If so, the control system controls the movement of the thread pulling lever 4, so that the other end of the thread pulling head 42 moves from the lower rear of the needle dropping hole 21 to the lower front, and during the movement, it pushes the bobbin thread between the rotary hook 3 and the needle plate 2, so that part of the bobbin thread crosses the axis where the sewing needle 10 is located. After that, the motor 5 continues to drive the thread pulling lever 4 to act, so that the other end of the thread pulling head 42 of the thread pulling lever 4 starts from the lower front of the needle dropping hole 21, moves to the side and away from the rotary hook 3, so that the other end of the thread pulling head 42 disengages from the bobbin thread. Subsequently, the sewing needle 10 continues to move downward to the lowest point, and then moves upward to form a loop of the upper thread on the sewing needle 10. During the upward movement of the sewing needle 10, the tip 32 of the rotary hook 3 hooks the upper thread on the sewing needle 10 from the front side of the sewing needle 10 and enlarges the loop of the upper thread, so that the loop of the upper thread is sleeved on the bobbin thread and intertwined with the bobbin thread. When the sewing needle 10 continues to move upward to the highest point, the upper thread and the bobbin thread are tightened to form a stitch. At the same time, the motor 5 continues to drive the thread pulling lever 4 to act, so that the other end of the thread pulling head 42 of the thread pulling lever 4 returns to the lower front of the needle dropping hole 21.

[0077] If not, the thread pulling lever 4 can be in a stationary waiting state, and the sewing machine sews normally, forming a positive shape stitch.

[0078] 4. Repeat step 3 and perform subsequent sewing according to the needle point trajectory obtained according to the sewing pattern.

[0079] The principle of realizing "stitch conversion" in this embodiment is similar to that in Embodiment 1, and will not be described in detail here.

[0080] Embodiment 3

[0081] The structure and principle of this embodiment are basically the same as those of Embodiment 1. The difference is that as Figure 13 shown, a motor 5 with a vertically arranged rotating shaft is fixedly installed on the motor base 1c. The rotating member 6 is strip-shaped. One end of the rotating member 6 is fixedly connected to the rotating shaft of the motor 5, and the other end is rotatably connected to the other end of the rod body 41. The rotating member 6 is strip-shaped, which is convenient to manufacture and has a low cost. At the same time, it can also stably drive the rod body 41 to reciprocate axially and swing. A slider 412 is integrally formed on the rod body 41. A chute 72 parallel to the rod body 41 is formed on the guide member 7. The slider 412 is slidably connected in the chute 72.

[0082] The specific embodiments described herein are only examples of the spirit of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the described specific embodiments or use similar methods to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0083] Although terms such as 1, base; 1a, seat body; 1a1, relief opening; 1b, connecting plate; 1c, motor base; 2, needle plate; 21, needle dropping hole; 3, rotary shuttle; 31, wire outlet; 32, shuttle tip; 4, thread guide rod; 41, rod body; 411, insertion hole; 42, thread guide head; 421, avoidance cutting surface; 43, connecting head; 5, motor; 6, rotating part; 7, guiding part; 71, guiding hole; 8, guiding sleeve; 9, locking screw; 10, sewing needle are used more frequently in this text, 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 limitation is contrary to the spirit of the present invention.

Claims

1. A sewing machine, comprising a base (1), a needle plate (2) having a needle insertion hole (21), and a rotary hook (3) located below the needle plate (2), characterized in that, The sewing machine further comprises a thread-moving rod (4) and a rotating member (6) capable of horizontal rotation. The base (1) is provided with a guide member (7) located at the side of the rotary shuttle (3) and capable of horizontal swinging. The thread-moving rod (4) comprises a rod body (41) and a thread-moving head (42) in the form of an arc strip. The rod body (41) is slidably connected to the guide member (7) along its axial direction. One end of the thread-moving head (42) is fixedly connected to one end of the rod body (41) close to the rotary shuttle (3) and is bent upward relative to the rod body (41). The other end of the rod body (41) is rotatably connected to a position on the rotating member (6) deviating from its rotation center. When the rotating member (6) drives the rod body (41) to move, the other end of the thread-moving head (42) can be located between the needle drop hole (21) and the rotary shuttle (3).

2. The sewing machine according to claim 1, characterized in that, The rod body (41) is in the shape of a straight rod and is arranged horizontally, and the wire-pulling head (42) is formed by bending a metal strip.

3. The sewing machine according to claim 1, characterized in that, When the rod body (41) moves to make the other end of the thread-pulling head (42) located between the needle-dropping hole (21) and the rotary hook (3), the thread-pulling head (42) is close to the outer peripheral wall of the rotary hook (3).

4. The sewing machine according to claim 1 or 2 or 3, characterized in that, The base (1) comprises a base body (1a) and a motor base (1c) fixedly connected to the outer wall of the base body (1a); a motor (5) with a vertically arranged rotating shaft is fixedly arranged on the motor base (1c); the rotating member (6) is a disc-shaped wire-pulling wheel; the rotating member (6) is connected to the rotating shaft of the motor (5) and is concentrically arranged.

5. The sewing machine according to claim 1 or 2 or 3, characterized in that, The base (1) comprises a base body (1a) and a motor base (1c) fixedly connected to the outer wall of the base body (1a); a motor (5) with a vertically arranged rotating shaft is fixedly arranged on the motor base (1c); the rotating member (6) is in a strip shape; one end of the rotating member (6) is fixedly connected to the rotating shaft of the motor (5), and the other end is rotatably connected to the other end of the rod body (41).

6. The sewing machine according to claim 4, characterized in that, The base (1) also includes a connecting plate (1b), the outer wall of the base body (1a) is provided with a clearance opening (1a1), the connecting plate (1b) passes through the clearance opening (1a1), the outer end of the connecting plate (1b) is fixedly connected to the motor base (1c), the inner end extends into the inner side of the base body (1a) and is close to the rotary shuttle (3), and the guide member (7) is rotatably connected to the inner end of the connecting plate (1b).

7. The sewing machine according to claim 3, characterized in that, The front side of the other end of the wire pulling head (42) has an avoidance cut surface (421), and when the rotating member (6) rotates, it can drive the rod body (41) to reciprocate along the axial direction and swing forward and backward at the same time, and the amplitude of the swing is smaller than the amplitude of the axial movement.

8. The sewing machine according to claim 1 or 2 or 3, characterized in that, An inserting hole (411) is provided on the end surface of the rod body (41) close to the rotary shuttle (3), and one end of the thread-pulling head (42) is matched and plugged into the inserting hole (411). A locking screw (9) is also screwed on the outer wall of the rod body (41), and the inner end of the locking screw (9) abuts against the thread-pulling head (42).

9. The sewing machine according to claim 1 or 2 or 3, characterized in that The guide member (7) has a guide hole (71), a guide sleeve (8) coaxially arranged therein is arranged in the guide hole (71), and the middle section of the rod body (41) is slidably inserted into the guide sleeve (8).

10. The sewing machine according to claim 1 or 2 or 3, characterized in that, A slider (412) is integrally formed on the rod body (41). A chute (72) parallel to the rod body (41) is formed on the guide member (7). The slider (412) is slidably connected in the chute (72).

Images