Sewing machine without oscillating seat

Abstract

The application provides a sewing machine without a swing seat, and relates to the technical field of sewing machine manufacturing, which comprises a connecting rod, a crank, a cloth feeding shaft and a driving source. The driving source drives the connecting rod in a rotary driving mode. The connecting rod is hinged with the crank. The crank is fixedly connected with the cloth feeding shaft. The sewing machine further comprises a static positioning wheel, an adjusting driving wheel, a connecting rod and a fork-shaped shifting rod. The adjusting driving wheel is fixed on the output shaft of the driving source. The connecting rod is hinged with the fork-shaped shifting rod. The fork-shaped shifting rod is mechanically matched with the adjusting driving wheel. The sliding part of the adjusting driving wheel is passively operated in the stitch length adjusting and positioning groove of the static positioning wheel. The sewing machine without the swing seat removes the swing seat technology used in the traditional sewing machine. The new stitch length is realized by changing the action position between the sliding part and the stitch length adjusting groove. The new stitch length is determined by the back-and-forth rotation angle of the driving source. The length of the stitch length adjusting groove is reasonably set to realize the multiple adjustment of the stitch length, and the sewing machine has high popularization and application value.

Description

Technical Field

[0001] The present application provides a sewing machine without a swing seat, and specifically relates to the technical field of sewing machine manufacturing. Background Art

[0002] The swing seat is an important and indispensable component in the traditional sewing machine structure for sewing. It is installed between the connecting rod and the feed shaft crank. In order to ensure the correspondence between the reverse stitch length and the forward stitch length, the stitch length adjustment function and the automatic reverse stitching function are both achieved by adjusting the angle of the swing seat. The stitch length adjustment of the swing seat is one of its important functions. The stitch length adjustment part drives the feed stud to adjust the angle of the swing seat in the front and back directions by rotating the stitch length dial, thereby achieving the change of stitch length; the automatic reverse stitching part drives the automatic reverse feed rod group through the automatic reverse feed electromagnet to drive the swing seat to a certain angle to achieve reverse stitching. Since the reverse stitch length is limited by the collision between the working arc surface of the adjuster and the head of the feed stud, long-term use will cause severe wear of the contact part between the stud and the feed adjuster, resulting in abnormal stitch length and affecting the sewing effect. At the same time, the noise of the swing seat is also relatively large when it is working.

[0003] In addition, the size of the stitch length of the swing seat with the needle length adjustment function is almost unique to a sewing machine. It is also difficult to implement the technical effect of multiple needles in the recently emerging sewing machines that use stepper motors to control and drive. Summary of the Invention

[0004] In response to the technical defects of the above-mentioned sewing machine swing seat, the present application solves multiple of the above-mentioned problems at the same time, and particularly proposes a sewing machine without a swing seat, which has a connecting rod, a crank, a cloth feed shaft and a driving source, and is characterized in that the driving source drives the connecting rod in a rotary driving manner, the connecting rod is hinged to the crank, and the crank is fixedly connected to the cloth feed shaft.

[0005] Preferably, the sewing machine also has a static positioning wheel, an adjusting wheel, a connecting rod and a fork-shaped shift lever, the adjusting wheel is fixed on the output shaft of the driving source, the connecting rod is hinged to the fork-shaped shift lever, the fork-shaped shift lever is mechanically coordinated with the adjusting wheel, and the sliding part of the adjusting wheel is passively operated in the stitch adjustment and positioning groove of the static positioning wheel.

[0006] Preferably, the sewing machine also has a support pin, the fork-shaped lever has a socket, the fork-shaped lever is inserted into the annular step of the adjusting wheel in the shape of the socket, the socket falls on the annular step, the connecting rod is hinged at the socket of the fork-shaped lever, the fork-shaped lever has a positioning hole that passes through the support pin, and the fork-shaped lever is connected to the support pin with a retaining spring.

[0007] Preferably, the sewing machine also has a slider, which is fixed on the output shaft of the driving source. A slide groove is provided at the center position of the adjusting wheel, and a slider is provided to match the internal gap of the slide groove. After the driving source drives the slider through the output shaft, the slider rotates and pushes the sliding part in the slide groove, causing the entire adjusting wheel to change the position of the fork-shaped lever in the stitch length adjustment and positioning groove along with the slider.

[0008] Preferably, the sliding member is arranged on the sliding groove, and the sliding member is arranged at an eccentric position of the adjusting wheel. The sliding member is higher than the adjusting wheel and extends to the inside of the stitch length adjustment and positioning groove of the static positioning wheel.

[0009] Preferably, the static positioning wheel is fixed on a body of the sewing machine, and the output shaft of the driving source passes through a through hole of the static positioning wheel.

[0010] Preferably, the sewing machine also has a feed dog, and the static positioning wheel has a stitch length adjustment and positioning groove, the stitch length adjustment and positioning groove is a closed groove, the through hole is located inside the stitch length adjustment and positioning groove, the stitch length adjustment and positioning groove has a stitch length adjustment groove, a positioning groove and a transition groove 1 and a transition groove 2 located between the stitch length adjustment groove and the positioning groove, the stitch length adjustment groove is used for stitch length adjustment, the positioning groove is used for positioning the zero point position of the feed dog, the transition groove 1 and the transition groove 2 play a transition role between the stitch length adjustment groove and the positioning groove, the positioning groove is used for zero position positioning of the feed dog and is also used for presser foot lifting action or thread cutting action, the action position change between the sliding part and the stitch length adjustment groove to achieve a new stitch length is determined by the size of the back and forth rotation angle of the driving source, and the feed dog finally sews with the new stitch length.

[0011] Preferably, the through hole of the static positioning wheel and the output shaft are arranged in concentric circles.

[0012] Preferably, the adjusting wheel is also provided with an axis slot hole and an axis hole. The axis hole is located at the center of the adjusting wheel. The axis slot hole is shaped like a long inner hole. The axis slot hole extends to the edge at the axis hole position. The axis holes are connected to the axis slot holes, and the output shaft occupies the axis slot hole during operation.

[0013] Preferably, the slide block is located outside the static positioning wheel and inside the regulating wheel. The cloth feed shaft indirectly changes the stitch length of the cloth feed dog.

[0014] The driving source of a sewing machine without a swing seat in the present application drives a connecting rod in a rotary drive mode. The connecting rod is hinged to a crank, and the crank is fixedly connected to the cloth feed shaft. This eliminates the traditional swing seat technology used in sewing machines and uses the action position change between the sliding member and the stitch length adjustment slot to achieve a new stitch length. The new stitch length is determined by the size of the back-and-forth rotation angle of the driving source. By reasonably setting the length of the stitch length adjustment slot, a variety of stitch length adjustments can be achieved, which not only reduces the cost of the sewing machine but also improves the intelligent control level of the sewing machine. The sewing machine without a swing seat in the present application breaks the design concept of traditional sewing machines and has high promotion and use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the exterior of a sewing machine without a swing seat according to the present application;

[0016] Figure 2 This is a schematic diagram of a zero-position positioning mechanism of a sewing machine without a swing seat in the present application;

[0017] Figure 3 This is a schematic diagram of a sewing machine adjusting wheel and a fork-shaped shift lever without a swing seat in the present application;

[0018] Figure 4 This is a schematic diagram of a sewing machine without a swing seat and a static positioning wheel;

[0019] Figure 5 This is a schematic diagram of the installation of a static positioning wheel and a slider of a sewing machine without a swing seat in the present application;

[0020] Figure 6 This is a structural diagram of a sewing machine adjusting wheel without a swing seat according to the present application;

[0021] Figure 7 This is a rear side view of a sewing machine adjusting wheel without a swing seat according to the present application;

[0022] Figure 8 This is a schematic diagram of the structure of the needle length adjustment and positioning groove of a sewing machine without a swing seat in the present application;

[0023] Figure 9 The present invention is a schematic diagram of a presser foot lifting mechanism and a thread trimming mechanism of a sewing machine without a swing seat.

[0024] Figure 1: Sewing machine 10, machine body 11, screw 12, drive source 20, output shaft 21, zero position positioning mechanism 40, static positioning wheel 41, through hole 411, stitch length adjustment and positioning groove 412, stitch length adjustment groove 4121, positioning groove 4122, transition groove one 4123, transition groove two 4124, adjusting wheel 42, slide groove 421, shaft slot hole 422, sliding member 423, annular step 424, shaft hole 425, connecting rod 44, slider 45, cloth feed shaft 46, fork-shaped lever 47, socket 471, support pin 48, crank 49, presser foot lifting mechanism 50, presser foot lifting cam 51, presser foot lifting push rod 52, thread trimming mechanism 60, thread trimming crank 61, pusher 611, thread trimming fork wheel 62, return rod 621, thread trimming rod 622, stitch length adjustment mechanism 70, feed dog 81, needle plate 82. DETAILED DESCRIPTION

[0025] The following is combined with Figure 1-9 The preferred embodiments of the present application are described in detail so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present application. These embodiments are only used to illustrate the present invention and are not intended to limit the present invention.

[0026] exist Figure 1 Figure 2 In the present application, an overall structural diagram of a sewing machine without a swing seat is proposed. The sewing machine 10 includes a driving source 20, a zero-position positioning mechanism 40, a presser foot lifting mechanism 50, a thread trimming mechanism 60 and a stitch length adjustment mechanism 70. The driving source 20 has an output shaft 21 which is installed and drives the zero-position positioning mechanism 40, the presser foot lifting mechanism 50, the thread trimming mechanism 60 and the stitch length adjustment mechanism 70 at different times. The present invention provides a sewing machine without a swing seat, meaning that the sewing machine 10 can achieve normal sewing operation without a swing seat. Specifically, the sewing machine 10 can adjust the stitch length of the stitch length adjustment mechanism 70 and simultaneously position the feed dog 81 at its zero position by the drive source 20 in a rotary operation mode. Furthermore, the drive source 20 can be used to perform the presser foot lifting action of the presser foot lifting mechanism 50 and the thread trimming action of the thread trimming mechanism 60. The drive source 20 performs the sewing actions of the above four mechanisms in different time periods and at different operating angles, thereby achieving the technical purpose of achieving the zero position of the feed dog 81 in a stable structure. The zero position of the feed dog is the zero stitch position in which the feed dog is below the needle plate 82. The drive source 20 is fixed to the side of the body 11 of the sewing machine 10, or to the back of the body 11. In this embodiment, the drive source 20 preferably uses a stepper motor or a servo motor.

[0027] Combine Figures 1 to 9The zero position positioning mechanism 40 includes a static positioning wheel 41, an adjusting dynamic wheel 42, a connecting rod 44, a sliding block 45, a cloth feeding shaft 46, a fork-shaped shifting lever 47, and a supporting pin 48. The static positioning wheel 41 is fixed on the machine body 11 and is fixed and static during its function. The output shaft 21 of the driving source 20 passes through the through hole 411 of the static positioning wheel 41, and the static positioning wheel 41 is fixed on the side of the machine body 11. The static positioning wheel 41 is fixed by a screw 12, and the static positioning wheel 41 is fixed on the side of the output shaft 21 close to the driving source 20, so that the output shaft 21 rotates in the through hole 411 of the static positioning wheel 41.

[0028] The through hole 411 of the static positioning wheel 41 and the output shaft 21 are concentrically arranged. The static positioning wheel 41 has a pitch adjusting and positioning groove 412, which is a closed groove. The through hole 411 is located in the inside of the pitch adjusting and positioning groove 412. The pitch adjusting and positioning groove 412 has a pitch adjusting groove 4121, a positioning groove 4122, and transition grooves one 4123 and two 4124 between the pitch adjusting groove 4121 and the positioning groove 4122. The pitch adjusting groove 4121 is used for pitch adjustment, the positioning groove 4122 is used for zero position positioning of the cloth feeding tooth 81, and the transition grooves one 4123 and two 4124 serve as the transition between the pitch adjusting groove 4121 and the positioning groove 4122. The positioning groove 4122 is used for zero position positioning of the cloth feeding tooth 81 and is applied to the lifting of the presser foot or the cutting of the thread.

[0029] The output shaft 21 of the driving source 20 is further provided with the adjusting dynamic wheel 42 and the sliding block 45. The sliding block 45 is fixed on the output shaft 21. In this embodiment, the center hole of the sliding block 45 is fixed on the output shaft 21 by a small screw. The sliding block 45 is located outside the static positioning wheel 41 and inside the adjusting dynamic wheel 42. The center of the adjusting dynamic wheel 42 is provided with a sliding groove 421, and the sliding block 45 is matched and arranged in the sliding groove 421. The sliding groove 421 is used for sliding of the sliding block 45 when the adjusting dynamic wheel 42 rotates.

[0030] The adjusting wheel 42 is provided with an axial slot 422, a sliding member 423, and an axial hole 425. The axial hole 425 is located at the center of the adjusting wheel 42 and is used to allow the output shaft 21 to rotate at the center of the adjusting wheel 42. The axial slot 422 is shaped like an elongated inner hole and extends toward the edge at the location of the axial slot 425. The axial hole 425 is connected to the axial slot 422. During operation, the output shaft 21 passes through the axial slot 422. The axial slot 422 is used to clear the operating output shaft 21 when the adjusting wheel 42 rotates. The sliding member 423 is disposed on the slide 421 and is located eccentrically on the adjusting wheel 42. The sliding member 423 is higher than the adjusting wheel 42 and extends into the stitch length adjustment and positioning slot 412 of the static positioning wheel 41. The sliding member 423 is restricted and passively operates within the stitch length adjustment slot 4121 of the stitch length adjustment and positioning slot 412. The drive source 20 rotates to drive the connecting rod 44, which is hinged to the crank 49, which is fixedly connected to the feed shaft 46. This technical solution eliminates the traditional swing seat technology used in sewing machines, offering high technical scalability. The slider 423 slides within the various operating slots within the stitch length adjustment and positioning slot 412, pushing the adjustment wheel 42. The adjustment wheel 42 in turn pushes the connecting rod 44, the crank 49, and the feed shaft 46 to indirectly change the stitch length of the feed dog 81.

[0031] The adjusting wheel 42 is movably connected to the interior of a fork-shaped lever 47, which is hinged to the connecting rod 44. The fork-shaped lever 47 has a socket 471, which is inserted into the annular step 424 of the adjusting wheel 42. The socket 471 fits into the annular step 424, creating a clearance fit between the socket 471 and the annular step 424. When the drive source 20 drives the slider 45 via the output shaft 21, the slider 45 rotates and pushes the sliding member 423 in the slot 421, causing the entire adjusting wheel 42 to change the position of the fork-shaped lever 47 in the stitch length adjustment and positioning slot 412 along with the slider 45. This positional change allows the fork-shaped lever 47 to meet the sewing needs of the feed dog 81.

[0032] It also has a support pin 48, which is fixed to the body 11 and is static. The fork-shaped lever 47 has a positioning hole that passes through the support pin 48. A movable device is provided between the fork-shaped lever 47 and the support pin 48. The fork-shaped lever 47 is rotatable on the support pin 48. In this embodiment, the fork-shaped lever 47 is movably connected to the support pin 48 by a retaining spring.

[0033] The driving source 20 has a needle length adjustment operating angle, a zero position positioning operating angle, a presser foot lifting operating angle and a thread trimming operating angle. The needle length adjustment and zero position positioning, the presser foot lifting action and the thread trimming action are all performed on the driving source 20 according to the above-mentioned preset operating angles. Each sewing action is performed at its own angle, and each operating angle is performed at a different time. In addition, the various operating angles do not interfere with each other, and each action is clear and distinct.

[0034] One end of the connecting rod 44 is hinged to the fork-shaped shift lever 47. The adjusting wheel 42 is driven by the driving source 20 in a rotational manner to drive the fork-shaped shift lever 47 and the connecting rod 44 to generate a swing source, thereby achieving stitch length adjustment and zero position positioning. Specifically, the connecting rod 44 is hinged at the socket 471 of the fork-shaped shift lever 47. During stitch length adjustment, the driving source 20 continuously rotates the slider 423 on the stitch length adjustment groove 4121, and a continuous swinging motion is generated between the adjusting wheel 42, the fork-shaped shift lever 47 and the connecting rod 44, so that the feed dog 81 can sew at the new stitch length. During zero position positioning, the driving source 20 indirectly rotates the slider 423 into the positioning groove 4122. The operation of the adjusting wheel 42 can make the fork-shaped shift lever 47 and the connecting rod 44 relatively static, so that the feed dog 81 is positioned at the zero point. The driving source 20 thereby performs the presser foot lifting action or the thread trimming action.

[0035] When the sewing machine 10 is to adjust the stitch length, the output shaft 21 of the drive source 20 drives the slider 45 at the original operating angle to drive the slider 423 to rotate. The rotational action changes the original working position of the slider 423 on the stitch length adjustment slot 4121. The drive source 20 drives the slider 45 to indirectly cause the feed dog 81 to produce a new stitch length through the fork-shaped lever 47 and the connecting rod 44. The change in the working position between the slider 423 and the stitch length adjustment slot 4121 to achieve a new stitch length is determined by the size of the back-and-forth rotation angle of the drive source 20. The feed dog 81 ultimately sews at the new stitch length. Therefore, the sewing machine of the present application can achieve multiple stitch length adjustments by setting the stitch length adjustment slot 4121 to a reasonable length.

[0036] When the sewing machine 10 is to perform the positioning zero action, the slider 423 passes from the stitch length adjusting groove 4121 to the positioning groove 4122 through the transition groove one 4123 or the transition groove two 4124. When the slider 423 enters the positioning groove 4122 from the transition groove one 4123 or the transition groove two 4124, that is, the slider 423 enters the positioning groove 4122, the slider 423 pushes the feed dog shaft 46 through the fork-shaped lever 47 and the connecting rod 44 to make the feed dog 81 enter the zero position. At this time, the positioning groove 4122 is arranged as a concentric circle with the output shaft 21, and the slider 423 pushes the output shaft 21 in the shaft groove hole 422 of the adjusting cam 42 to the center position of the adjusting cam 42 under the driving of the output shaft 21. The determination of the zero point position of the feed dog 81 effectively solves the problem of inaccurate positioning of the zero position of the existing sewing machine, improves the stability of sewing, and thus improves the sewing quality.

[0037] Since the insertion port 471 of the fork-shaped lever 47 and the annular step 424 of the adjusting cam 42 are gap-fitted, the positions of the connecting rod 44 and the adjusting cam 42 are mutually constrained, and the reliable mechanical connection between the adjusting cam 42 and the connecting rod 44 is achieved, thereby realizing the reliability of the positioning of the zero point position of the feed dog 81 and overcoming the defect of low stability in positioning in the prior art.

[0038] After the slider 423 performs a new stitch length in the stitch length adjusting groove 4121, the driving source 20 continues to operate to the positioning groove 4122 at this time, and the slider 423 gives the fork-shaped lever 47, the connecting rod 44 and the feed dog shaft 46 no swing source transmission. The driving source 20 drives the output shaft 21 to drive the adjusting cam 42 to idle in the insertion port 471 of the connecting rod 44, at this time, the sewing machine 10 commands the driving source 20 in the positioning groove 4122 to perform the presser foot lifting action of the presser foot lifting mechanism 50 and the thread cutting action of the thread cutting mechanism 60.

[0039] Referring to the drawings Figure 2 Figure 9 The sewing machine without swing seat of the present application comprises a presser foot lifting mechanism 50 and a thread cutting mechanism 60. When the sewing machine 10 finishes sewing, the thread cutting action needs to be performed first and then the presser foot lifting action, and the driving source 20 performs the presser foot lifting action at the presser foot running corner and performs the thread cutting action at the thread cutting running corner.

[0040] The thread cutting mechanism 60 has a thread cutting crank 61, a thread cutting fork wheel 62 and a thread cutting final execution end; the presser foot lifting mechanism 50 has a presser foot lifting cam 51, a presser foot lifting jack 52 and a presser foot lifting final execution end. The thread cutting crank 61 and the presser foot lifting cam 51 are installed on the output shaft 21, the thread cutting crank 61 is located at the outermost side of the output shaft 21, and the presser foot lifting cam 51 is located between the adjusting cam 42 and the thread cutting crank 61 close to the side of the adjusting cam 42.

[0041] When the drive source 20 is performing the thread trimming operation at the thread trimming operation angle, the output shaft 21 is located at the center of the adjusting wheel 42. Regardless of how the output shaft 21 rotates, the adjusting wheel 42 is always in an idle state in the socket 471 of the fork-shaped lever 47. The entire length of the positioning groove 4122 is sufficient to allow the drive source 20 to perform the presser foot lifting operation and the thread trimming operation at the presser foot lifting operation angle and the thread trimming operation angle.

[0042] A pusher 611 is provided at an eccentric position of the trimming crank 61. The trimming fork wheel 62 has a return rod 621 and a trimming rod 622. The pusher 611 is located between the return rod 621 and the trimming rod 622. The driving source 20 drives the pusher 611 to rotate and press the trimming rod 622 downward to transmit the force to the trimming end actuator to trim the thread, and the trimming end actuator completes the thread trimming action. After the thread trimming is completed, the driving source 20 continues to drive the pusher 611 to rotate to the return rod 621, returning the return rod 621 to its original position, thereby completing the reset of the entire trimming mechanism 60.

[0043] After thread trimming is completed, the sewing machine 10 immediately performs the presser foot lifting action. The drive source 20 drives the presser foot lifting cam 51 at the presser foot lifting operation angle. The arc surface of the presser foot lifting cam 51 is an idle surface, and the cam surface of the presser foot lifting cam 51 is a lifting surface for the presser foot lifting action. The drive source 20 drives the output shaft 21 to rotate the presser foot lifting cam 51, which uses the lifting surface to lift the presser foot lifting push rod 52. The presser foot lifting push rod 52 prompts the presser foot lifting terminal to perform the presser foot lifting action. The establishment of the above idle surface prevents the output shaft 21 from actually affecting the presser foot lifting action when performing other sewing actions.

[0044] The above is only one of the preferred implementation methods of this application, and does not limit the scope of patent implementation of this application. Any equivalent structure or equivalent process transformation based on the shape, structure, and principle of the description and drawings of this application, or direct or indirect application in other related technical fields, is included in the scope of patent protection of this application.

Claims

1. A sewing machine without a swing seat, comprising a connecting rod (44), a crank (49), a cloth feed shaft (46) and a drive source (20), characterized in that: The driving source (20) drives the connecting rod (44) in a rotary driving manner, the connecting rod (44) is hinged to the crank (49), and the crank (49) is fixedly connected to the cloth feeding shaft (46); The sewing machine (10) further comprises a static positioning wheel (41), an adjusting wheel (42), a connecting rod (44) and a fork-shaped shifting lever (47); the adjusting wheel (42) is fixed on an output shaft (21) of a driving source (20); the connecting rod (44) is hinged to the fork-shaped shifting lever (47); the fork-shaped shifting lever (47) is mechanically matched with the adjusting wheel (42); a sliding member (423) of the adjusting wheel (42) is passively operated in a stitch length adjusting positioning groove (412) of the static positioning wheel (41); The sewing machine (10) further comprises a support pin (48), the fork-shaped shift lever (47) having a socket (471), the fork-shaped shift lever (47) being inserted into an annular step (424) of the adjusting wheel (42) in the shape of the socket (471), the socket (471) falling into the annular step (424), the connecting rod (44) being hinged at the socket (471) of the fork-shaped shift lever (47), the fork-shaped shift lever (47) having a positioning hole passing through the support pin (48), and the fork-shaped shift lever (47) being movably connected to the support pin (48) by a snap spring; The sewing machine (10) further comprises a slider (45), the slider (45) being fixed on the output shaft (21) of the driving source (20), a slide groove (421) being provided at the center position of the regulating wheel (42), the internal gap of the slide groove (421) being matched with the slider (45), after the driving source (20) drives the slider (45) through the output shaft (21), the slider (45) rotates and pushes the sliding member (423) in the slide groove (421), causing the entire regulating wheel (42) to change the position of the fork-shaped shifting lever (47) in the stitch length regulating positioning groove (412) along with the slider (45); the slider (45) being located outside the static positioning wheel (41) and inside the regulating wheel (42), and the cloth feed shaft (46) indirectly changing the stitch length of the cloth feed dog (81); The static positioning wheel (41) has a needle distance adjustment positioning groove (412), which is a closed groove. The through hole (411) is located inside the needle distance adjustment positioning groove (412). The needle distance adjustment positioning groove (412) has a needle distance adjustment groove (4121), a positioning groove (4122), a transition groove 1 (4123) and a transition groove 2 (4124) located between the needle distance adjustment groove (4121) and the positioning groove (4122). The needle distance adjustment groove (4121) is used for needle distance adjustment, and the positioning groove (4122) is used for adjusting the needle distance. The feed dog (81) is positioned at the zero point, and the transition groove 1 (4123) and the transition groove 2 (4124) play a transition role between the stitch length adjustment groove (4121) and the positioning groove (4122). The positioning groove (4122) is used for positioning the feed dog (81) at the zero point and is also used for the presser foot lifting action or the thread cutting action. The change in the action position between the sliding member (423) and the stitch length adjustment groove (4121) to achieve a new stitch length is determined by the size of the back-and-forth rotation angle of the driving source (20). The feed dog (81) finally sews with the new stitch length.

2. A sewing machine without a swing seat according to claim 1, characterized in that: The sliding member (423) is arranged on the sliding groove (421), and the sliding member (423) is arranged at an eccentric position of the adjusting wheel (42). The sliding member (423) is higher than the adjusting wheel (42) and extends to the inside of the needle distance adjustment positioning groove (412) of the static positioning wheel (41).

3. A sewing machine without a swing seat according to claim 1, characterized in that: The static positioning wheel (41) is fixed on a body (11) of the sewing machine (10), and the output shaft (21) of the driving source (20) passes through a through hole (411) of the static positioning wheel (41).

4. A sewing machine without a swing seat according to claim 1, characterized in that: The through hole (411) of the static positioning wheel (41) and the output shaft (21) are arranged in a concentric circle.

5. The sewing machine without a swing seat according to claim 1, characterized in that: The regulating wheel (42) is further provided with an axis slot hole (422) and an axis hole (425). The axis hole (425) is located at the center of the regulating wheel (42). The axis slot hole (422) is shaped like an elongated inner hole. The axis slot hole (422) extends toward the edge at the position of the axis hole (425). The axis hole (425) is connected to the axis slot hole (422). The output shaft (21) occupies the axis slot hole (422) during operation.

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