Stitch length electronic adjusting method and stitch length electronic adjusting system of sewing machine and overedger

Abstract

The invention discloses a stitch length electronic adjusting method and system of a sewing machine and an overlock machine. The stitch length electronic adjusting method of the sewing machine comprises the steps that a control mechanism outputs a stitch length adjusting signal; the spindle motor controls the spindle to rotate by a certain angle, and the needle opening eccentric cam rotates along with the spindle to enable the second circumferential surface section or the fourth circumferential surface section to rotate to face the needle opening pin; the needle pitch motor controls the needle opening pin to act and abut against the second circumferential surface section or the fourth circumferential surface section. The main shaft motor controls the main shaft to rotate by a certain angle, the needle opening eccentric cam rotates along with the main shaft so that the first circumferential face section can rotate to face the needle opening pin, the needle opening pin can enter the needle opening groove in the first circumferential face section and exert certain acting force on the pawl so that the pawl can be separated from the ratchet wheel, and then the follow-up needle pitch adjusting action can be conducted. The problem that the needle pitch adjusting function fails due to abrasion of the needle opening pin can be avoided, and the needle pitch adjusting function can still be achieved after the needle opening pin is abraded.

Description

Technical Field

[0001] This invention belongs to the field of sewing machine technology, specifically relating to a method for electronically adjusting the stitch length of a sewing machine, an electronically adjusting the stitch length system, and an overlock sewing machine. Background Technology

[0002] With the popularization of electronics, electronic stitch length adjustment technology is becoming increasingly common in overlock sewing machines. Compared with the original stitch length adjustment methods, most electronic stitch length adjustment methods involve driving the needle release pin through a stitch length motor. This causes the needle release pin to press against the needle release groove on the circumferential surface of the needle release eccentric cam, and the pawl, which slides radially on the surface of the needle release eccentric cam, separates from the ratchet fixed on the main shaft, thus achieving stitch length adjustment. However, because the driving force of the stitch length motor is often much greater than that of manual operation, the wear problem of the needle release pin is aggravated. After the needle release pin wears down, the stitch length adjustment function is prone to failure. Specifically:

[0003] like Figures 1-3 As shown, the circumferential surface of the eccentric cam 2 is divided into four segments, which are respectively called the first circumferential surface segment 201, the second circumferential surface segment 202, the third circumferential surface segment 203, and the fourth circumferential surface segment 204 in a clockwise direction. The first circumferential surface segment 201 and the third circumferential surface segment 203 have the same width and are arranged opposite each other. The second circumferential surface segment 202 and the fourth circumferential surface segment 204 have the same width and are arranged opposite each other. Furthermore, the width of the first circumferential surface segment 201 is smaller than the width of the second circumferential surface segment 202. Figure 5As shown, when the needle spacing motor 5 controls the opening pin 301 to move, the opening pin 301 abuts against a corresponding segment of the circumferential surface of the opening eccentric cam 2. Then, the main spindle motor 1 drives the main spindle 6 to rotate. Since the pawl 7, which slides radially on the surface of the opening eccentric cam 2, meshes with the ratchet 8, which is sleeved and fixed on the main spindle 6, the opening eccentric cam 2, sleeved on the main spindle 6, rotates along with the main spindle 6. However, since the exact position of the opening pin 301 abutting against the circumferential surface of the opening eccentric cam 2 is uncertain, the opening pin 301 may need to pass through different points during the rotation of the opening eccentric cam 2 by the main spindle 6. The needle pin 301 passes through the first circumferential segment 201, the second circumferential segment 202, the third circumferential segment 203, and the fourth circumferential segment 204 of the needle-opening eccentric cam 2 until it enters the needle-opening groove 20101 on the first circumferential segment 201. This applies a certain force to the pawl 7, causing it to separate from the ratchet 8, thus facilitating the needle pitch adjustment. The surface of the needle-opening pin 301 that abuts against the circumferential surface of the needle-opening eccentric cam 2 is called the needle-opening pin contact surface. During the passage of the needle-opening pin 301 through the first circumferential segment 201, the rear part of the needle-opening pin contact surface will... The pin 301 contacts and rubs against the first circumferential segment 201, while the front part of the pin abutting surface hangs to one side of the first circumferential segment 201 without friction. Similarly, as the pin 301 passes through the third circumferential segment 203, the rear part of the pin abutting surface contacts and rubs against the third circumferential segment 203, while the front part of the pin abutting surface hangs to one side of the third circumferential segment 203 without friction. As the pin 301 passes through the second circumferential segment 202, the entire surface of the pin abutting surface, both the front and rear parts, contacts the second circumferential segment 202. 02. Contact and friction occur. Similarly, during the process of the needle pin 301 passing through the fourth circumferential segment 204, the entire surface of the needle pin abutting surface, i.e., both the front and rear parts, will contact and rub against the fourth circumferential segment 204. Thus, after long-term use, the wear of the rear part of the needle pin abutting surface is more severe than that of the front part. During the rotation of the needle pin eccentric cam 2 driven by the main shaft 6, when the needle pin 301 transitions from the narrower first circumferential segment 201 or the third circumferential segment 203 to the wider second circumferential segment 202 or the fourth circumferential segment 204, it is prone to the following: Figure 4 The problem shown is that the front part of the needle opening pin abutment surface gets stuck at the junction between two adjacent segments on the needle opening eccentric cam 2, causing the needle spacing adjustment function to fail. Summary of the Invention

[0004] In view of the above-mentioned defects of the prior art, the present invention provides a method, system and machine for electronic adjustment of stitch length of a sewing machine, which can avoid the problem of failure of the stitch length adjustment function due to wear of the needle pin, and can still achieve the function of stitch length adjustment after the needle pin is worn.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A method for electronically adjusting the stitch length of a sewing machine includes the following steps:

[0007] S1. The control mechanism of the sewing machine outputs a signal to adjust the stitch length;

[0008] S2. The main spindle motor controls the main spindle to rotate at a certain angle. The needle-opening eccentric cam sleeved on the main spindle rotates at a certain angle with the main spindle, so that the second or fourth circumferential segment of the needle-opening eccentric cam rotates to face the needle-opening pin.

[0009] S3. The needle pitch motor controls the action of the needle opening pin, so that the needle opening pin hits the second or fourth circumferential segment of the needle opening eccentric cam.

[0010] S4. The spindle motor controls the spindle to rotate at a certain angle, and the needle-opening eccentric cam rotates at a certain angle along with the spindle, so that the first circumferential segment of the needle-opening eccentric cam rotates to face the needle-opening pin, and the needle-opening pin enters the needle-opening groove on the first circumferential segment. A certain force is applied to the pawl that is radially slidably set on the surface of the needle-opening eccentric cam, so that the pawl separates from the ratchet fixed on the spindle. Then, the subsequent needle pitch adjustment action is performed. The first circumferential segment is located between the second circumferential segment and the fourth circumferential segment, and the width of the first circumferential segment is smaller than the width of the second circumferential segment and the fourth circumferential segment.

[0011] Furthermore, it also includes the following steps:

[0012] S5. After completing the subsequent stitch length adjustment, the stitch length motor controls the needle opening pin to move in the reverse direction, causing the needle opening pin to exit the needle opening slot, and the pawl to re-engage with the ratchet under the action of the reset component.

[0013] Further, step S3 specifically involves the needle pitch motor controlling the needle opening assembly to move via the linkage assembly, causing the needle opening pin at one end of the needle opening assembly to move and press against the second or fourth circumferential segment of the needle opening eccentric cam.

[0014] Further, in step S3: the linkage assembly includes a first linkage and a second linkage. One end of the first linkage is fixedly connected to the output shaft of the needle pitch motor, the other end of the first linkage is hinged to one end of the second linkage, the other end of the second linkage is fixedly connected to the needle opening assembly, and the needle opening pin is fixed at one end of the needle opening assembly.

[0015] Furthermore, in step S5: the reset component is a torsion spring, one end of which is fixed to the surface of the eccentric cam and the other end is fixedly connected to the pawl.

[0016] Furthermore,

[0017] Step S2 is as follows: The spindle motor controls the spindle to rotate at a certain angle, and the needle-opening eccentric cam sleeved on the spindle rotates at a certain angle along with the spindle, so that the second circumferential surface segment of the needle-opening eccentric cam rotates to face the needle-opening pin.

[0018] Step S3 specifically involves: the needle pitch motor controlling the action of the needle opening pin, causing the needle opening pin to press against the second circumferential segment of the needle opening eccentric cam;

[0019] Step S4 is as follows: The spindle motor controls the spindle to rotate clockwise by a certain angle, and the needle-opening eccentric cam rotates clockwise by a certain angle along with the spindle, so that the first circumferential segment of the needle-opening eccentric cam rotates to face the needle-opening pin, and the needle-opening pin enters the needle-opening groove on the first circumferential segment. A certain force is applied to the pawl that is radially slidably set on the surface of the needle-opening eccentric cam, so that the pawl is separated from the ratchet fixed on the spindle, and then the subsequent needle pitch adjustment action is performed.

[0020] Furthermore,

[0021] Step S2 is as follows: The spindle motor controls the spindle to rotate at a certain angle, and the needle-opening eccentric cam sleeved on the spindle rotates at a certain angle along with the spindle, so that the fourth circumferential segment of the needle-opening eccentric cam rotates to face the needle-opening pin.

[0022] Step S3 specifically involves: the needle pitch motor controlling the action of the needle opening pin, causing the needle opening pin to press against the fourth circumferential segment of the needle opening eccentric cam;

[0023] Step S4 is as follows: The spindle motor controls the spindle to rotate counterclockwise by a certain angle, and the needle-opening eccentric cam rotates counterclockwise by a certain angle along with the spindle, so that the first circumferential segment of the needle-opening eccentric cam rotates to face the needle-opening pin, and the needle-opening pin enters the needle-opening groove on the first circumferential segment. A certain force is applied to the pawl that is radially slidably set on the surface of the needle-opening eccentric cam, so that the pawl is separated from the ratchet fixed on the spindle, and then the subsequent needle pitch adjustment action is performed.

[0024] An electronic stitch length adjustment system for a sewing machine, used to execute the aforementioned electronic stitch length adjustment method for a sewing machine, includes a main shaft motor, a main shaft, an eccentric cam for opening the needle, an opening pin, a stitch length motor, a pawl, and a ratchet. The main shaft is driven to rotate by the main shaft motor. The eccentric cam for opening the needle is sleeved on the main shaft. The circumferential surface of the eccentric cam for opening the needle is divided into four segments, which are respectively called the first circumferential surface segment, the second circumferential surface segment, the third circumferential surface segment, and the fourth circumferential surface segment in a clockwise direction. The pawl is slidably disposed on the surface of the eccentric cam for opening the needle and engages with the ratchet, which is sleeved and fixed on the main shaft. The opening pin for opening the needle is driven by the stitch length motor to actuate, causing the opening pin to press against the circumferential surface of the eccentric cam for opening the needle and enter the opening groove on the first circumferential surface segment, thereby separating the pawl from the ratchet, or causing the opening pin to exit the opening groove and causing the pawl to re-engage with the ratchet.

[0025] Furthermore, it also includes a reset assembly, a linkage assembly, and a needle-opening assembly. One end of the reset assembly is fixed to the surface of the needle-opening eccentric cam, and the other end is fixedly connected to a pawl. The linkage assembly includes a first linkage and a second linkage. One end of the first linkage is fixedly connected to the output shaft of the needle pitch motor, and the other end of the first linkage is hinged to one end of the second linkage. The other end of the second linkage is fixedly connected to the needle-opening assembly, and the needle-opening pin is fixed at one end of the needle-opening assembly.

[0026] An overlock sewing machine includes the above-described electronic needle length adjustment system for sewing machines.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] The electronic needle length adjustment method for a sewing machine in this invention includes the following steps: S1, the control mechanism of the sewing machine outputs a signal to adjust the needle length; S2, the main shaft motor controls the main shaft to rotate at a certain angle, and the needle-opening eccentric cam sleeved on the main shaft rotates at the same angle, causing the second or fourth circumferential segment of the needle-opening eccentric cam to rotate to face the needle-opening pin; S3, the needle length motor controls the needle-opening pin to move, causing the needle-opening pin to abut against the second or fourth circumferential segment of the needle-opening eccentric cam; S4, the main shaft motor controls the main shaft to rotate at a certain angle, and the needle-opening pin... The eccentric cam rotates at a certain angle along with the main shaft, causing the first circumferential segment of the eccentric cam to face the needle opening pin. This allows the needle opening pin to enter the needle opening groove on the first circumferential segment, and applies a certain force to the pawl that slides radially on the surface of the eccentric cam, causing the pawl to separate from the ratchet fixed on the main shaft. Subsequent needle pitch adjustment is then performed. The first circumferential segment is located between the second and fourth circumferential segments, and the width of the first circumferential segment is smaller than the widths of the second and fourth circumferential segments. As the eccentric cam rotates with the main shaft, the needle-opening pin moves from the wider second or fourth circumferential segment to the narrower first circumferential segment. This ensures that even if the rear of the needle-opening pin's contact surface is more worn than the front, the front of the contact surface will not jam at the junction of the adjacent second and first circumferential segments on the eccentric cam, or at the junction of the adjacent fourth and first circumferential segments. Therefore, the needle-pitch adjustment function will not fail, and the needle-pitch adjustment function can be smoothly achieved. In summary, this invention avoids the problem of needle-pitch adjustment function failure due to needle-opening pin wear, and can still achieve 100% needle-pitch adjustment even after the needle-opening pin has worn. Attached Figure Description

[0029] Figure 1 A schematic diagram of the main structure showing the contact between the opening pin and the eccentric cam.

[0030] Figure 2 A three-dimensional structural diagram showing one direction of the contact between the opening pin and the opening eccentric cam;

[0031] Figure 3 A three-dimensional structural diagram showing the contact between the opening pin and the eccentric cam in another direction;

[0032] Figure 4 A schematic diagram showing the structure in which the front part of the opening pin abutting surface gets stuck at the junction between the third and fourth circumferential segments when the opening pin transitions from the narrower third circumferential segment to the wider fourth circumferential segment on the opening eccentric cam.

[0033] Figure 5 A three-dimensional structural diagram of the electronic needle length adjustment system of a sewing machine;

[0034] Figure 6 for Figure 5 A partially enlarged structural diagram;

[0035] Figure 7 for Figure 5 A partially enlarged structural diagram from another direction;

[0036] Figure 8 This is a flowchart of the electronic needle length adjustment method for the sewing machine in this invention.

[0037] The following are the annotations in the figure: 1. Main spindle motor; 2. Needle opening eccentric cam; 201. First circumferential segment; 20101. Needle opening groove; 202. Second circumferential segment; 203. Third circumferential segment; 204. Fourth circumferential segment; 3. Needle opening assembly; 301. Needle opening pin; 401. First connecting rod; 402. Second connecting rod; 5. Needle pitch motor; 6. Main spindle; 7. Pawl; 8. Ratchet. Detailed Implementation

[0038] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0039] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] A method for electronically adjusting the stitch length of a sewing machine includes the following steps:

[0042] S1. The control mechanism of the sewing machine outputs a signal to adjust the stitch length;

[0043] S2. The main spindle motor 1 controls the main spindle 6 to rotate at a certain angle. The needle-opening eccentric cam 2 sleeved on the main spindle 6 rotates at a certain angle along with the main spindle 6, so that the second circumferential surface segment 202 or the fourth circumferential surface segment 204 of the needle-opening eccentric cam 2 rotates to face the needle-opening pin 301.

[0044] S3, the needle pitch motor 5 controls the action of the needle opening pin 301, so that the needle opening pin 301 presses against the second circumferential surface segment 202 or the fourth circumferential surface segment 204 of the needle opening eccentric cam 2.

[0045] S4. The main spindle motor 1 controls the main spindle 6 to rotate at a certain angle. The needle-opening eccentric cam 2 rotates at the same angle as the main spindle 6, causing the first circumferential segment 201 of the needle-opening eccentric cam 2 to rotate to face the needle-opening pin 301. This causes the needle-opening pin 301 to enter the needle-opening groove 20101 on the first circumferential segment 201, and applies a certain force to the pawl 7, which is radially slidably disposed on the surface of the needle-opening eccentric cam 2, so that the pawl 7 separates from the ratchet 8 fixed on the main spindle 6. Subsequent needle pitch adjustment is then performed. The first circumferential segment 201 is located between the second circumferential segment 202 and the fourth circumferential segment 204, and the width of the first circumferential segment 201 is smaller than the widths of the second circumferential segment 202 and the fourth circumferential segment 204. (See...) Figures 1-3 as well as Figures 5-7 ;

[0046] S5. After completing the subsequent stitch length adjustment, the stitch length motor 5 controls the needle opening pin 301 to reverse, causing the needle opening pin 301 to exit the needle opening groove 20101, and the pawl 7 to re-engage with the ratchet 8 under the action of the reset component.

[0047] Once the pawl 7 separates from the ratchet 8 fixed on the main shaft 6, the subsequent stitch length adjustment is prior art in this field and will not be described in detail here.

[0048] As the eccentric cam 2 rotates with the main shaft 6, the needle-opening pin 301 moves from the wider second circumferential segment 202 or fourth circumferential segment 204 on the eccentric cam 2 into the narrower first circumferential segment 201. Thus, even if the rear part of the needle-opening pin 301's contact surface is more worn than the front part, the front part of the needle-opening pin 301's contact surface still maintains a relatively high wear level between the adjacent second circumferential segment 202 and first circumferential segment 201 on the eccentric cam 2. There will be no jamming at the interface, or at the junction of the front part of the abutting surface of the needle opening pin 301 and the fourth circumferential surface segment 204 and the first circumferential surface segment 201 adjacent to the needle opening eccentric cam 2, there will be no jamming. Therefore, the problem of failure of the needle spacing adjustment function will not occur, and the needle spacing adjustment function can be realized smoothly. In summary, the present invention can avoid the problem of failure of the needle spacing adjustment function due to wear of the needle opening pin 301, and can still realize the needle spacing adjustment function 100% after the needle opening pin 301 is worn.

[0049] Furthermore, in the background technology, since the exact position of the needle-opening pin 301 abutting the circumferential surface of the needle-opening eccentric cam 2 is uncertain, during the rotation of the needle-opening eccentric cam 2 driven by the main shaft 6, there is a possibility that the needle-opening pin 301 needs to pass through the second circumferential surface segment 202, the third circumferential surface segment 203, and the fourth circumferential surface segment 204 of the needle-opening eccentric cam 2 in sequence before entering the needle-opening groove 20101 on the first circumferential surface segment 201. In this case, the rotation angle of the needle-opening eccentric cam 2 driven by the main shaft 6 is close to 360 degrees. In this invention, as the needle-opening eccentric cam 2 rotates with the main shaft 6, the needle-opening pin 301 enters the needle-opening groove 20101 on the first circumferential segment 201 from the second circumferential segment 202 or the fourth circumferential segment 204 of the needle-opening eccentric cam 2. Then, the main shaft 6 drives the needle-opening eccentric cam 2 to rotate at an angle close to 90°. Therefore, compared with the main shaft 6 rotating at an angle close to 360° in the prior art, the main shaft 6 can rotate at an angle close to 90° in this invention, thereby improving the speed of needle spacing adjustment.

[0050] In one embodiment,

[0051] Step S3 is as follows: The needle pitch motor 5 controls the needle opening assembly 3 to move through the linkage assembly, so that the needle opening pin 301 at one end of the needle opening assembly 3 moves and presses against the second circumferential segment 202 or the fourth circumferential segment 204 of the needle opening eccentric cam 2.

[0052] Step S5 is as follows: After completing the subsequent stitch length adjustment action, the stitch length motor 5 controls the needle opening assembly 3 to reverse its action through the linkage assembly, so that the needle opening pin 301 at one end of the needle opening assembly 3 reverses its action and exits the needle opening groove 20101. The pawl 7 loses the force of the needle opening pin 301 and re-engages with the ratchet 8 under the action of the reset assembly.

[0053] Preferably, in step S3: the connecting rod assembly includes a first connecting rod 401 and a second connecting rod 402. One end of the first connecting rod 401 is fixedly connected to the output shaft of the needle pitch motor 5, and the other end of the first connecting rod 401 is hinged to one end of the second connecting rod 402. The other end of the second connecting rod 402 is fixedly connected to the needle opening assembly 3, and the needle opening pin 301 is fixed at one end of the needle opening assembly 3. Specifically, the left end of the first connecting rod 401 is fixedly connected to the front end of the output shaft of the needle pitch motor 5, the right end of the first connecting rod 401 is hinged to the front end of the second connecting rod 402, the rear end of the second connecting rod 402 is fixedly connected to the needle opening assembly 3, and the needle opening pin 301 is fixed at one end of the needle opening assembly 3. See [link to documentation]. Figure 5 .

[0054] In one embodiment, in step S5: the reset component is a torsion spring, one end of which is fixed to the surface of the eccentric cam 2 and the other end is fixedly connected to the pawl 7.

[0055] In one embodiment,

[0056] Step S2 is as follows: the spindle motor 1 controls the spindle 6 to rotate at a certain angle, and the needle-opening eccentric cam 2 sleeved on the spindle 6 rotates at a certain angle along with the spindle 6, so that the second circumferential surface segment 202 of the needle-opening eccentric cam 2 rotates to face the needle-opening pin 301.

[0057] Step S3 specifically involves the needle pitch motor 5 controlling the action of the needle opening pin 301, causing the needle opening pin 301 to press against the second circumferential segment 202 of the needle opening eccentric cam 2.

[0058] Step S4 is as follows: The spindle motor 1 controls the spindle 6 to rotate clockwise by a certain angle, and the needle opening eccentric cam 2 rotates clockwise by a certain angle along with the spindle 6, so that the first circumferential surface segment 201 of the needle opening eccentric cam 2 rotates to face the needle opening pin 301, and the needle opening pin 301 enters the needle opening groove 20101 on the first circumferential surface segment 201, and applies a certain force to the pawl 7 that is radially slidably set on the surface of the needle opening eccentric cam 2, so that the pawl 7 is separated from the ratchet 8 fixed on the spindle 6, and then the subsequent needle pitch adjustment action is performed.

[0059] In one embodiment,

[0060] Step S2 is as follows: the spindle motor 1 controls the spindle 6 to rotate at a certain angle, and the needle-opening eccentric cam 2 sleeved on the spindle 6 rotates at a certain angle along with the spindle 6, so that the fourth circumferential surface segment 204 of the needle-opening eccentric cam 2 rotates to face the needle-opening pin 301.

[0061] Step S3 specifically involves the needle pitch motor 5 controlling the action of the needle opening pin 301, causing the needle opening pin 301 to press against the fourth circumferential segment 204 of the needle opening eccentric cam 2.

[0062] Step S4 is as follows: The spindle motor 1 controls the spindle 6 to rotate counterclockwise by a certain angle, and the needle opening eccentric cam 2 rotates counterclockwise by a certain angle along with the spindle 6, so that the first circumferential segment 201 of the needle opening eccentric cam 2 rotates to face the needle opening pin 301, and the needle opening pin 301 enters the needle opening groove 20101 on the first circumferential segment 201, and applies a certain force to the pawl 7 that is radially slidably set on the surface of the needle opening eccentric cam 2, so that the pawl 7 separates from the ratchet 8 fixed on the spindle 6, and then the subsequent needle pitch adjustment action is performed.

[0063] like Figures 5-7 As shown, a stitch length electronic adjustment system for a sewing machine, used to execute the above-mentioned stitch length electronic adjustment method for a sewing machine, includes a main shaft motor 1, a main shaft 6, a needle-opening eccentric cam 2, a needle-opening pin 301, a stitch length motor 5, a pawl 7, and a ratchet 8. The main shaft 6 is driven to rotate by the main shaft motor 1. The needle-opening eccentric cam 2 is sleeved on the main shaft 6. The circumferential surface of the needle-opening eccentric cam 2 is divided into four segments, which are respectively called the first circumferential surface segment 201, the second circumferential surface segment 202, and the third circumferential surface segment 203 in a clockwise direction. 03 and the fourth circumferential segment 204, the pawl 7 is radially slidably disposed on the surface of the needle-opening eccentric cam 2 and meshes with the ratchet 8 sleeved and fixed on the main shaft 6, the needle-opening pin 301 is driven by the needle pitch motor 5 to move, so that the needle-opening pin 301 abuts against the circumferential surface of the needle-opening eccentric cam 2 and enters the needle-opening groove 20101 on the first circumferential segment 201, so that the pawl 7 is separated from the ratchet 8, or the needle-opening pin 301 is removed from the needle-opening groove 20101 and the pawl 7 is re-engaged with the ratchet 8.

[0064] In one embodiment, the electronic needle pitch adjustment system of the sewing machine further includes a reset assembly, a linkage assembly, and a needle opening assembly 3. One end of the reset assembly is fixed to the surface of the needle opening eccentric cam 2, and the other end is fixedly connected to the pawl 7. The linkage assembly includes a first linkage 401 and a second linkage 402. One end of the first linkage 401 is fixedly connected to the output shaft of the needle pitch motor 5, and the other end of the first linkage 401 is hinged to one end of the second linkage 402. The other end of the second linkage 402 is fixedly connected to the needle opening assembly 3, and the needle opening pin 301 is fixed at one end of the needle opening assembly 3.

[0065] An overlock sewing machine includes the above-described electronic needle length adjustment system for sewing machines.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A method for electronically adjusting the stitch length of a sewing machine, characterized in that, Includes the following steps: S1. The control mechanism of the sewing machine outputs a signal to adjust the stitch length; S2. The main spindle motor (1) controls the main spindle (6) to rotate at a certain angle. The needle-opening eccentric cam (2) sleeved on the main spindle (6) rotates at a certain angle along with the main spindle (6), so that the second circumferential segment (202) or the fourth circumferential segment (204) of the needle-opening eccentric cam (2) rotates to face the needle-opening pin (301). S3. The needle pitch motor (5) controls the action of the needle opening pin (301), so that the needle opening pin (301) presses against the second circumferential segment (202) or the fourth circumferential segment (204) of the needle opening eccentric cam (2); S4. The main spindle motor (1) controls the main spindle (6) to rotate at a certain angle. The needle opening eccentric cam (2) rotates at a certain angle along with the main spindle (6), so that the first circumferential segment (201) of the needle opening eccentric cam (2) rotates to face the needle opening pin (301), and the needle opening pin (301) enters the needle opening groove (20101) on the first circumferential segment (201), and applies a certain force to the pawl (7) that slides radially on the surface of the needle opening eccentric cam (2), so that the pawl (7) separates from the ratchet (8) fixed on the main spindle (6), and then performs the subsequent needle pitch adjustment action. The first circumferential segment (201) is located between the second circumferential segment (202) and the fourth circumferential segment (204), and the width of the first circumferential segment (201) is smaller than the width of the second circumferential segment (202) and the fourth circumferential segment (204).

2. The method for electronically adjusting the stitch length of a sewing machine according to claim 1, characterized in that, It also includes the following steps: S5. After completing the subsequent needle pitch adjustment action, the needle pitch motor (5) controls the needle opening pin (301) to move in the opposite direction, so that the needle opening pin (301) exits the needle opening groove (20101), and the pawl (7) re-engages with the ratchet (8) under the action of the reset component.

3. The method for electronically adjusting the stitch length of a sewing machine according to claim 2, characterized in that, Step S3 is as follows: The needle pitch motor (5) controls the action of the needle opening assembly (3) through the linkage assembly, so that the needle opening pin (301) at one end of the needle opening assembly (3) moves and presses against the second circumferential segment (202) or the fourth circumferential segment (204) of the needle opening eccentric cam (2).

4. The method for electronically adjusting the stitch length of a sewing machine according to claim 3, characterized in that, In step S3: the linkage assembly includes a first linkage (401) and a second linkage (402). One end of the first linkage (401) is fixedly connected to the output shaft of the needle pitch motor (5). The other end of the first linkage (401) is hinged to one end of the second linkage (402). The other end of the second linkage (402) is fixedly connected to the needle opening assembly (3). The needle opening pin (301) is fixed at one end of the needle opening assembly (3).

5. The method for electronically adjusting the stitch length of a sewing machine according to claim 2, characterized in that, In step S5: the reset component is a torsion spring, one end of which is fixed on the surface of the opening needle eccentric cam (2) and the other end is fixedly connected to the pawl (7).

6. The method for electronically adjusting the stitch length of a sewing machine according to claim 2, characterized in that, Step S2 is as follows: The spindle motor (1) controls the spindle (6) to rotate at a certain angle, and the needle-opening eccentric cam (2) sleeved on the spindle (6) rotates at a certain angle along with the spindle (6), so that the second circumferential surface segment (202) of the needle-opening eccentric cam (2) rotates to face the needle-opening pin (301). Step S3 is as follows: The needle pitch motor (5) controls the action of the needle opening pin (301) so that the needle opening pin (301) presses against the second circumferential segment (202) of the needle opening eccentric cam (2); Step S4 is as follows: The spindle motor (1) controls the spindle (6) to rotate clockwise by a certain angle, and the needle opening eccentric cam (2) rotates clockwise by a certain angle along with the spindle (6), so that the first circumferential surface segment (201) of the needle opening eccentric cam (2) rotates to face the needle opening pin (301), and the needle opening pin (301) enters the needle opening groove (20101) on the first circumferential surface segment (201), and applies a certain force to the pawl (7) that slides radially on the surface of the needle opening eccentric cam (2), so that the pawl (7) separates from the ratchet (8) fixed on the spindle (6), and then performs the subsequent needle pitch adjustment action.

7. The method for electronically adjusting the stitch length of a sewing machine according to claim 2, characterized in that, Step S2 is as follows: The spindle motor (1) controls the spindle (6) to rotate at a certain angle, and the needle-opening eccentric cam (2) sleeved on the spindle (6) rotates at a certain angle along with the spindle (6), so that the fourth circumferential surface segment (204) of the needle-opening eccentric cam (2) rotates to face the needle-opening pin (301). Step S3 is as follows: the needle pitch motor (5) controls the action of the needle opening pin (301) so that the needle opening pin (301) presses against the fourth circumferential segment (204) of the needle opening eccentric cam (2); Step S4 is as follows: The spindle motor (1) controls the spindle (6) to rotate counterclockwise by a certain angle, and the needle opening eccentric cam (2) rotates counterclockwise by a certain angle along with the spindle (6), so that the first circumferential surface segment (201) of the needle opening eccentric cam (2) rotates to face the needle opening pin (301), and the needle opening pin (301) enters the needle opening groove (20101) on the first circumferential surface segment (201), and applies a certain force to the pawl (7) that slides radially on the surface of the needle opening eccentric cam (2), so that the pawl (7) separates from the ratchet (8) fixed on the spindle (6), and then performs the subsequent needle pitch adjustment action.

8. A stitch length electronic adjustment system for a sewing machine, used to perform the stitch length electronic adjustment method for a sewing machine as described in any one of claims 1-7, characterized in that: The system includes a main spindle motor (1), a main spindle (6), a needle-opening eccentric cam (2), a needle-opening pin (301), a needle-pitch motor (5), a pawl (7), and a ratchet (8). The main spindle (6) is driven to rotate by the main spindle motor (1). The needle-opening eccentric cam (2) is mounted on the main spindle (6). The circumferential surface of the needle-opening eccentric cam (2) is divided into four segments, which are respectively called the first circumferential surface segment (201), the second circumferential surface segment (202), the third circumferential surface segment (203), and the fourth circumferential surface segment (204) in a clockwise direction. The pawl (7) The needle opening pin (301) is radially slidably disposed on the surface of the needle opening eccentric cam (2) and meshes with the ratchet (8) sleeved and fixed on the main shaft (6). The needle opening pin (301) is driven by the needle pitch motor (5) to move, so that the needle opening pin (301) abuts against the circumferential surface of the needle opening eccentric cam (2) and enters the needle opening groove (20101) on the first circumferential surface segment (201), so that the pawl (7) is separated from the ratchet (8), or the needle opening pin (301) is removed from the needle opening groove (20101) and the pawl (7) is re-engaged with the ratchet (8).

9. The electronic needle spacing adjustment system for a sewing machine according to claim 8, characterized in that: It also includes a reset assembly, a linkage assembly and a needle opening assembly (3). One end of the reset assembly is fixed on the surface of the needle opening eccentric cam (2) and the other end is fixedly connected to the pawl (7). The linkage assembly includes a first linkage (401) and a second linkage (402). One end of the first linkage (401) is fixedly connected to the output shaft of the needle pitch motor (5). The other end of the first linkage (401) is hinged to one end of the second linkage (402). The other end of the second linkage (402) is fixedly connected to the needle opening assembly (3). The needle opening pin (301) is fixed at one end of the needle opening assembly (3).

10. An overlock sewing machine, characterized in that: Includes the electronic needle length adjustment system for the sewing machine as described in claim 8.

Images