Thread trimming, stitch length adjusting and presser foot lifting mechanism of sewing machine

Abstract

The utility model relates to the technical field of sewing machines, in particular to a thread trimming, stitch length adjusting and presser foot lifting mechanism of a sewing machine. Under the driving of the first driver, the thread trimming transmission rod rotates and presses the thread trimming crank, the thread trimming crank presses the hinged thread trimming connecting rod, and the pressed thread trimming connecting rod enables the indirectly connected thread trimming execution end to execute thread trimming action; after thread trimming is completed, under reverse driving of the first driver, the cutter return device is lifted to drive the thread trimming connecting rod to be lifted, then the thread trimming connecting rod enables the thread trimming execution end to return a cutter, resetting of the thread trimming mechanism is completed, good mechanical performance is achieved, mechanical noise is greatly reduced, the cutter return device part participates in thread trimming action and full-time cutter return action, and the thread trimming mechanism is convenient to operate. And the mechanical noise generated by the cutter returning action of the cutter returning device is greatly reduced.

Description

Technical Field

[0001] The present application relates to the technical field of sewing machines, and specifically proposes a thread trimming, stitch length adjustment and presser foot lifting mechanism for a sewing machine. Background Art

[0002] Using a stepper motor to control each sewing action of a sewing machine is one of the most advocated technologies at present. National patent CN111719251A proposes a structure and a sewing machine controlled by one motor for multiple sewing actions, including a motor, a presser foot lifting mechanism, a reverse stitching mechanism and a thread trimming mechanism. The motor includes an electromagnet and / or a relay, an encoder, a front output shaft and a rear output shaft. The front output shaft of the motor controls the thread trimming mechanism, the rear output shaft of the motor controls the presser foot lifting mechanism and the reverse stitching mechanism, the rear output shaft is fixed with a presser foot lifting cam and a reverse stitching cam, the rear output shaft of the motor passes through the electromagnet, the front output shaft is fixed with a tangent curved rod, the front output shaft of the motor passes through the encoder, the rear output shaft of the motor repeatedly rotates forward and reverse in the corner to output power to realize the reverse stitching (stitch length adjustment) action, and the front output shaft of the motor realizes the thread trimming action by rotating forward once in the corner. The thread trimming mechanism includes a tangent crank and a tangent drive crank, the tangent crank is fixed on the front shaft, the tangent crank has a crank ball, the tangent drive crank has a crank hole, the crank ball is installed in the crank hole of the tangent drive crank, and the motor of the thread trimming mechanism outputs power in one forward rotation within the angle. However, the structure and component structure of this scheme are relatively complex, and it is difficult to mass produce in manufacturing and processing. In particular, the tangent drive crank participates in the pushing and returning knife thread trimming actions, and the mechanical noise generated is relatively large, which affects the quality of the sewing machine. Summary of the invention

[0003] The present application is aimed at the problem of high noise of the thread trimming mechanism of the above-mentioned sewing machine, and proposes a thread trimming mechanism of the sewing machine, characterized in that the thread trimming mechanism comprises a first driver, a thread trimming transmission rod, a thread trimming crank, a thread trimming connecting rod, a knife return device, a knife return bracket and a thread trimming execution end, the first driver has a driving shaft on which a thread trimming transmission rod is fixed and a thread trimming crank is sleeved, under the drive of the first driver, the thread trimming transmission rod rotates to press down the thread trimming crank, and the pressed thread trimming crank presses down the hinged thread trimming connecting rod, and the pressed down thread trimming connecting rod makes the indirectly connected thread trimming execution end perform the thread trimming action; when the thread trimming is completed, under the reverse drive of the first driver, the knife return device is lifted up to drive the thread trimming connecting rod to lift up, and then the thread trimming connecting rod makes the thread trimming execution end return the knife, completing the resetting of the thread trimming mechanism, having good mechanical properties and greatly reducing mechanical noise.

[0004] The thread trimmer transmission rod and the thread trimmer crank are placed close together to facilitate the thread trimmer crank to lift the thread trimmer transmission rod.

[0005] Furthermore, the knife return device has a lifting part, the trimmer crank has a push rod, and the trimmer connecting rod has a force rod. The push rod of the trimmer crank is located at the yielding part of the knife return device and the upper part of the trimmer connecting rod, and the force rod is located above the lifting part. When the trimmer crank starts to press down, the push rod presses down the trimmer connecting rod, so that the force rod and the lifting part are pressed down together, that is, the trimmer connecting rod is pressed down; when the trimmer crank starts to lift, the push rod lifts the yielding part, and the knife return device lifts up to drive the lifting part to lift the force rod, thereby realizing the lifting of the trimmer connecting rod. Here, the knife return device part participates in the thread cutting action and is dedicated to the knife return action, so that the mechanical noise generated by the knife return action of the knife return device is greatly reduced.

[0006] The knife return device can be movably arranged on the knife return bracket, and the knife return bracket is fixed on the sewing machine body.

[0007] In addition, a stitch length adjustment mechanism of a sewing machine is proposed, characterized in that the first driver and the stitch length adjustment mechanism have a stitch length crank, a stitch length connecting rod, a swing seat and a feed dog, the stitch length crank is fixed on the driving shaft, the stitch length crank is hinged to the stitch length connecting rod, and the other end of the stitch length connecting rod is hinged to the swing seat; the swing amplitude of the swing seat is changed by the stitch length crank and the stitch length connecting rod, and the feed amplitude of the feed dog is indirectly changed, thereby realizing the stitch length adjustment action of the sewing machine, and the stitch length crank is fixed on the side of the driving shaft close to the first driver.

[0008] In addition, a presser foot lifting mechanism of a sewing machine is introduced, characterized in that the presser foot lifting mechanism is provided with a presser foot lifting cam, a presser foot lifting lever, a presser foot lifting connecting rod, a presser foot rod and a presser foot, the second driver is provided with a driving shaft, the presser foot lifting cam is fixed on the driving shaft, the presser foot lifting lever is movably arranged on the machine body, the presser foot lifting lever is provided with a shaft sleeve, the presser foot lifting cam rotates to contact the shaft sleeve to push the presser foot lifting lever to move, the other end of the presser foot lifting lever is hinged to the presser foot lifting connecting rod, and the other end of the presser foot lifting connecting rod is indirectly connected to the presser foot rod and the presser foot.

[0009] The presser foot lifting cam has a lifting contour surface and an origin contour surface. When the second driver is driven, the sleeve is transferred from the origin contour surface of the presser foot lifting cam to the lifting contour surface, the sleeve is gradually pushed, and the presser foot lifting connecting rod is pulled under the action of the presser foot lifting lever.

[0010] Furthermore, when the sleeve contacts the highest point of the lifting contour surface, the presser foot reaches the highest point. When the presser foot is to be lowered, the second driver drives in the opposite direction, and the highest point begins to separate from the sleeve, gradually separates from the lifting contour surface and enters the origin contour surface. The second driver stops driving, and the presser foot is lowered on the needle plate, completing a presser foot lifting process.

[0011] The first driver is fixedly installed on the side of the sewing machine head, and the second driver is fixedly installed on the rear side of the sewing machine head. Both the first driver and the second driver are electrically connected to the control system.

[0012] Compared with the prior art, the beneficial effects of the present application are as follows: under the drive of the first driver, the thread trimming transmission rod rotates and presses down the thread trimming crank, which in turn presses down the hinged thread trimming connecting rod, and the pressed down thread trimming connecting rod enables the indirectly connected thread trimming execution end to perform the thread trimming action; when the thread trimming is completed, under the reverse drive of the first driver, the knife return device is lifted up to drive the thread trimming connecting rod to lift up, and then the thread trimming connecting rod causes the thread trimming execution end to return the knife, completing the resetting of the thread trimming mechanism, having good mechanical properties, and greatly reducing mechanical noise, the knife return device does not participate in the thread trimming action, and is dedicated to the knife return action, so that the mechanical noise generated by the knife return action of the knife return device is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of a thread trimming, stitch length adjustment and presser foot lifting mechanism of a sewing machine of the present application;

[0014] Figure 2 It is a schematic diagram of a thread trimming and stitch length adjustment mechanism of a sewing machine of the present application;

[0015] Figure 3 It is an enlarged schematic diagram of a thread trimming and stitch length adjustment mechanism of a sewing machine of the present application;

[0016] Figure 4 This is a schematic diagram of the structure of a knife return device in a thread trimming mechanism of a sewing machine of the present application;

[0017] Figure 5 It is a schematic diagram of a presser foot lifting mechanism of a sewing machine of the present application;

[0018] Figure 6 It is an enlarged schematic diagram of the presser foot lifting drive of a sewing machine of the present application.

[0019] The specific feature names indicated by the numbers in the above drawings are as follows:

[0020] 10 thread trimming mechanism, 11 first driver, 111 driving shaft, 12 thread trimming transmission rod, 13 thread trimming crank, 131 pushing rod, 14 thread trimming connecting rod, 141 force bearing rod, 15 knife return device, 151 lifting part, 152 giving way part, 16 knife return bracket, 17 thread trimming execution end.

[0021] 20 needle pitch adjustment mechanism, 21 needle pitch crank, 22 needle pitch connecting rod, 23 swing seat, 24 feed dog.

[0022] 30 presser foot lifting mechanism, 31 second driver, 311 driving shaft, 32 presser foot lifting cam, 321 lifting contour surface, 321 highest point, 322 origin contour surface, 33 presser foot lifting lever, 331 shaft sleeve, 34 presser foot lifting connecting rod, 35 presser foot rod, 36 presser foot. DETAILED DESCRIPTION

[0023] The following is combined with Figure 1-6 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 explicit definition of the protection scope of the present application. These embodiments are only used to illustrate the present invention, but not to limit the present invention. In addition, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description, and are not used to limit the scope of the present invention. The change or adjustment of their relative relationship shall also be regarded as the scope of the present invention without substantial change in the technical content.

[0024] Referring to the above drawings, a sewing machine of the present application has a thread trimming mechanism 10, a stitch length adjustment mechanism 20, a presser foot lifting mechanism 30 and a control system, etc. The thread trimming mechanism 10 performs the thread trimming action of the sewing machine under the control of the control system, the stitch length adjustment mechanism 20 performs the stitch length adjustment action of the sewing machine under the control of the control system, and the presser foot lifting mechanism 30 also performs the presser foot lifting action of the sewing machine under the control of the control system. Among them, the thread trimming mechanism 10 and the stitch length adjustment mechanism 20 are realized under the drive of the first driver 11 of the sewing machine, and the presser foot lifting mechanism 30 is realized under the drive of the second driver 31 of the sewing machine. In addition, the first driver 11 is installed and fixed at the side position of the sewing machine head, and the second driver 31 is installed and fixed at the rear position of the sewing machine head. The first driver 11 and the second driver 31 are both electrically connected to the control system.

[0025] The thread trimming mechanism 10 comprises components such as a thread trimming transmission rod 12, a thread trimming crank 13, a thread trimming connecting rod 14, a knife return device 15, a knife return bracket 16 and a thread trimming execution end 17. The first driver 11 has a driving shaft 111 on which the thread trimming transmission rod 12 and a stitch crank 21 are fixed, and the thread trimming crank 13 is sleeved. The thread trimming transmission rod 12 and the thread trimming crank 13 are close to each other.

[0026] Driven by the first driver 11, the thread trimming transmission rod 12 rotates to press down the thread trimming crank 13, which in turn presses down the hinged thread trimming connecting rod 14, and the pressed thread trimming connecting rod 14 causes the indirectly connected thread trimming execution end 17 to execute the thread trimming action. When the thread trimming is completed, the thread trimming knife needs to be returned immediately. Under the reverse drive of the first driver 11, the knife return device 15 is lifted up to drive the thread trimming connecting rod 14 to lift up, and then the thread trimming connecting rod 14 causes the thread trimming execution end 17 to return the knife quickly, completing the reset of the thread trimming mechanism.

[0027] The knife return device 15 is movably arranged on the knife return bracket 16, and the knife return bracket 16 is fixed on the sewing machine body. The knife return device 15 has a lifting portion 151 and a yielding portion 152, the thread trimmer crank 13 has a push rod 131, and the thread trimmer connecting rod 14 has a force rod 141. The push rod 131 of the thread trimmer crank 13 is located above the yielding portion 152 of the knife return device 15 and the thread trimmer connecting rod 14, and the force rod 141 is located above the lifting portion 151. When the thread trimmer crank 13 starts to press down, the push rod 131 presses down the thread trimmer connecting rod 14, so that the force rod 141 and the lifting portion 151 are pressed down together, that is, the thread trimmer connecting rod 14 is pressed down. When the thread trimmer crank 13 starts to lift, the push rod 131 lifts the yielding portion 152, and the knife return device 15 lifts up to drive the lifting portion 151 to lift the force rod 141, thereby realizing the lifting of the thread trimmer connecting rod 14. Here, the knife return device partly participates in the thread trimming action and is dedicated to the knife return action, so that the mechanical noise generated by the knife return action of the knife return device is greatly reduced.

[0028] The stitch length adjustment mechanism 20 comprises components such as a first driver 11, a stitch length crank 21, a stitch length connecting rod 22, a swing seat 23 and a feed dog 24. The stitch length crank 21 is fixed on the drive shaft 111 and is located on the side close to the first driver 11; the stitch length crank 21 is hinged to the stitch length connecting rod 22, and the other end of the stitch length connecting rod 22 is hinged to the swing seat 23, and the swing seat 23 can output a swing source and indirectly transmit the swing source to the feed dog 24. When the stitch length needs to be adjusted, the first driver 11 is driven to rotate a certain angle under the control of the control system, and the swing amplitude of the swing seat 23 is changed by the stitch length crank 21 and the stitch length connecting rod 22, and the feed amplitude of the feed dog 24 is indirectly changed, thereby realizing the stitch length adjustment action of the sewing machine, and the sewing machine can sew at the new stitch length.

[0029] In the above-mentioned thread trimming mechanism 10 and needle length adjustment mechanism 20, the first driver 11 drives these two mechanisms to perform two sewing actions at different times, so that the thread trimming mechanism 10 can be driven without affecting the needle length adjustment mechanism 20; and the needle length adjustment mechanism 20 can be driven without interfering with the thread trimming mechanism 10.

[0030] The presser foot lifting mechanism 30 comprises components such as a second driver 31, a presser foot lifting cam 32, a presser foot lifting lever 33, a presser foot lifting connecting rod 34, a presser foot rod 35 and a presser foot 36. The second driver 31 comprises a driving shaft 311, on which the presser foot lifting cam 32 is fixed, the presser foot lifting lever 33 is movably arranged on the machine body, a shaft sleeve 331 is arranged on the presser foot lifting lever 33, the presser foot lifting cam 32 rotates to contact the shaft sleeve 331 so as to push the presser foot lifting lever 33 to move, the other end of the presser foot lifting lever 33 is hinged to the presser foot lifting connecting rod 34, and the other end of the presser foot lifting connecting rod 34 is indirectly connected to the presser foot rod 35 and the presser foot 36.

[0031] The presser foot lifting cam 32 has a lifting contour surface 321 and an origin contour surface 322. When the second driver 31 is driven, the sleeve 331 is transferred from the origin contour surface 322 of the presser foot lifting cam 32 to the lifting contour surface 321, and the sleeve 331 is gradually pushed. Under the action of the presser foot lifting lever 33, the presser foot lifting connecting rod 34 is pulled. When the sleeve 331 contacts the highest point 3211 of the lifting contour surface 321, the presser foot is at the highest position. When the presser foot is to be lowered, the second driver 31 drives in the reverse direction, and the highest point 3211 begins to separate from the sleeve 331, gradually separates from the lifting contour surface 321 and enters the origin contour surface 322. The second driver 31 stops driving, and the presser foot is placed on the needle plate, completing a presser foot lifting process.

[0032] The above is only one of the preferred implementation methods of the present application and is not intended to limit the present invention. The scope of the patent implementation of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made by using the shape, structure, and principle of the description and drawings of the present application, or directly or indirectly applied in other related technical fields; any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention are included in the patent protection scope of the present application.

Claims

1. A thread trimming mechanism for a sewing machine, characterized in that: The thread trimming mechanism comprises a first driver, a thread trimming transmission rod, a thread trimming crank, a thread trimming connecting rod, a knife return device, a knife return bracket and a thread trimming execution end. The first driver has a driving shaft on which a thread trimming transmission rod is fixed and a thread trimming crank is sleeved. When driven by the first driver, the thread trimming transmission rod rotates and presses down the thread trimming crank, which in turn presses down the hinged thread trimming connecting rod. The pressed down thread trimming connecting rod enables the indirectly connected thread trimming execution end to perform the thread trimming action. When the thread trimming is completed, under the reverse drive of the first driver, the knife return device is lifted up to drive the thread trimming connecting rod to lift up, and then the thread trimming connecting rod causes the thread trimming execution end to return the knife, thereby completing the resetting of the thread trimming mechanism.

2. A thread trimming mechanism for a sewing machine according to claim 1, characterized in that: The thread trimmer transmission rod and the thread trimmer crank are close to each other.

3. The thread trimming mechanism of a sewing machine according to claim 1, characterized in that: The knife return device has a lifting part, the thread trimmer crank has a pushing rod, and the thread trimmer connecting rod has a force rod. The pushing rod of the thread trimmer crank is located at the yielding part of the knife return device and the upper part of the thread trimmer connecting rod, and the force rod is located above the lifting part.

4. A thread trimming mechanism for a sewing machine according to claim 3, characterized in that: The knife return device has a yielding portion. When the thread trimmer crank starts to press down, the push rod presses down the thread trimmer connecting rod, so that the force-bearing rod and the lifting portion are pressed down together, that is, the thread trimmer connecting rod is pressed down; when the thread trimmer crank starts to lift, the push rod lifts the yielding portion, and the knife return device lifts up to drive the lifting portion to lift the force-bearing rod, thereby realizing the lifting of the thread trimmer connecting rod.

5. The thread trimming mechanism of a sewing machine according to claim 3, characterized in that: The knife return device can be movably arranged on the knife return bracket, and the knife return bracket is fixed on the sewing machine body.

6. A needle distance adjustment mechanism for a sewing machine, characterized in that: The stitch length adjustment mechanism comprises a first driver, a stitch length crank, a stitch length connecting rod, a swing seat and a feed dog. The stitch length crank is fixed on the driving shaft, the stitch length crank is hinged to the stitch length connecting rod, and the other end of the stitch length connecting rod is hinged to the swing seat. The swing amplitude of the swing seat is changed by the stitch length crank and the stitch length connecting rod, and the cloth feeding amplitude of the feed dog is changed indirectly, thereby realizing the stitch length adjustment action of the sewing machine. The stitch length crank is fixed on the side of the driving shaft close to the first driver.

7. A presser foot lifting mechanism for a sewing machine, characterized in that: The presser foot lifting mechanism comprises a presser foot lifting cam, a presser foot lifting lever, a presser foot lifting connecting rod, a presser foot rod and a presser foot. The second driver comprises a driving shaft, on which the presser foot lifting cam is fixed. The presser foot lifting lever is movably arranged on the machine body. A shaft sleeve is arranged on the presser foot lifting lever. The presser foot lifting cam rotates to contact the shaft sleeve to push the presser foot lifting lever to move. The other end of the presser foot lifting lever is hinged to the presser foot lifting connecting rod, and the other end of the presser foot lifting connecting rod is indirectly connected to the presser foot rod and the presser foot.

8. The presser foot lifting mechanism of a sewing machine according to claim 7, characterized in that: The presser foot lifting cam has a lifting contour surface and an origin contour surface. When the second driver is driven, the sleeve moves from the origin contour surface of the presser foot lifting cam to the lifting contour surface, the sleeve is gradually pushed, and the presser foot lifting connecting rod is pulled under the action of the presser foot lifting lever.

9. The presser foot lifting mechanism of a sewing machine according to claim 7, characterized in that: When the sleeve contacts the highest point of the lifting contour surface, the presser foot reaches the highest point. When the presser foot is to be lowered, the second driver drives in the reverse direction, the highest point begins to separate from the sleeve, gradually separates from the lifting contour surface and enters the origin contour surface. The second driver stops driving, and the presser foot is lowered on the needle plate, completing a presser foot lifting process.

10. A thread trimming mechanism or stitch length adjusting mechanism or presser foot lifting mechanism for a sewing machine according to claim 1 or 6 or 7, characterized in that: The first driver is fixedly installed on the side of the sewing machine head, and the second driver is fixedly installed on the rear side of the sewing machine head. Both the first driver and the second driver are electrically connected to the control system.

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