CN-121992589-A - Bird nest thread cutting prevention method based on small-gauge seam lifting and wire bonding linkage control

CN121992589ACN 121992589 ACN121992589 ACN 121992589ACN-121992589-A

Abstract

The application provides a bird nest thread cutting prevention method based on small needle distance seam lifting and thread cutting linkage control, which comprises the steps that after a seam lifting instruction is received, an electronic control unit controls a sewing machine to lift a first needle, a second needle, a first needle and a second needle until an N-th needle in a small needle distance sewing mode, a seam lifting stitch is formed on a fabric, the seam lifting stitch does not enter between a material pressing part and a middle needle plate of the sewing machine, a thread cutting driving source drives a main thread cutter and an auxiliary thread cutter to engage a thread head of a shearing surface, then a thread clamp is loosened, a thread clamp clamps threads, the electronic control unit controls the sewing machine to continue sewing with a target needle distance, when a thread picking rod moves downwards to pay-off, the thread driving source drives a thread plate to swing and thread, the thread plate pulls back a part of an upper thread on the fabric, and when the thread picking rod moves upwards to pay-off, the thread clamp is loosened, and the upper thread on the fabric continues to be pulled back a part. The method effectively shortens the length of the residual thread ends of the bird nest on the fabric after the bird nest is prevented from cutting the thread, and has better bird nest preventing effect.

Inventors

LI ZHIWEI
CHEN CHANGXI
LU BIN
LI WEINAN
KE XIANGLIN

Assignees

杰克科技股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260325

Claims (10)

1. A bird nest thread cutting prevention method based on small-gauge seam lifting and wire bonding linkage control is characterized by comprising the following steps of: S1, configuring an electric control unit, a bird nest preventing thread cutting mechanism, a thread bonding mechanism, a main thread clamp, a first thread loosening driving source, a presser foot and a thread taking-up lever capable of vertically reciprocating in a sewing machine, wherein the first thread loosening driving source is in transmission connection with the main thread clamp; the bird nest preventing thread cutting mechanism comprises a thread cutting driving source, a main thread cutting knife in transmission connection with the thread cutting driving source and an auxiliary thread cutting knife, wherein the main thread cutting knife is provided with a thread hooking groove and a main thread cutting knife, and the auxiliary thread cutting knife is provided with an auxiliary thread cutting knife; The wire bonding mechanism comprises a wire bonding driving source, a wire bonding plate capable of swinging, a wire bonding device and a second wire loosening driving source in transmission connection with the wire bonding device, wherein the wire bonding driving source is in transmission connection with the wire bonding plate, and a second wire passing hole is formed in the wire bonding plate; The presser foot comprises a presser foot bottom plate, a needle passing groove which is arranged in the presser foot bottom plate and penetrates up and down, and a pressing part which is formed by a presser foot bottom plate entity part, wherein the pressing part and the needle passing groove are distributed back and forth along the feeding direction of the sewing machine during normal sewing; The upper thread in the sewing machine sequentially passes through the thread-clamping device, the second thread-passing hole, the main thread-clamping device and the first thread-passing hole and then passes into a needle of the sewing machine; The first loose wire driving source, the shearing wire driving source, the wire bonding driving source and the second loose wire driving source are all in communication connection with the electric control unit; s2, the electronic control unit receives a seam starting instruction; the electronic control unit controls the first loose wire driving source to act so as to drive the main wire clamping device to clamp wires; S3, the electronic control unit controls the sewing machine to start sewing the first needle, the second needle, the third needle and the N needle in a small-stitch sewing mode, and stitch starting marks are formed on the fabric and do not enter between the material pressing part and a needle plate in the sewing machine; In the process of starting the first needle, the electronic control unit controls the thread cutting driving source to act, drives the main thread cutting knife to extend out and then back, and enables the upper thread end on one side of the needle to penetrate into the thread hooking groove; s4, the electric control unit controls the line cutting driving source to act, and drives the main line cutting knife to move towards the auxiliary line cutting knife, so that the main line cutting knife and the auxiliary line cutting knife are meshed, and line ends are cut; s5, the electric control unit controls the first loose wire driving source to reset and controls the second loose wire driving source to act so as to drive the main wire clamp to loose wires and the wire bonding wire clamp to clamp wires; S6, the electronic control unit controls the sewing machine to continue sewing with the target stitch length; in the process of continuing to sew the first needle, when the thread take-up lever moves downwards to pay off, the electronic control unit controls the thread-making driving source to act so as to drive the thread-making plate to swing and make threads, and the thread-making plate withdraws part of upper threads on the fabric; And when the take-up lever moves upwards to take up the thread, the electronic control unit controls the first thread loosening driving source to act and controls the second thread loosening driving source to reset, so as to drive the main thread clamp to clamp the thread and the thread clamp to loosen the thread, and the take-up lever continuously withdraws part of the upper thread on the fabric.
2. The method for preventing bird nest from trimming as claimed in claim 1, wherein the step S3 comprises the following steps: s31, before the first needle is sewn by the sewing machine or in the process that the first needle moves downwards by the sewing machine, the electric control unit controls the thread cutting driving source to act, and the thread cutting driving source drives the main thread cutting knife to move so that the thread hooking groove is positioned right below the needle; S32, an electric control unit controls the sewing machine to start a first needle in a small-stitch sewing mode, the needle moves downwards, the needle passes through a needle groove and a thread hooking groove, and under the action of a rotating shuttle in the sewing machine, an upper thread head on one side of the needle is brought to the position below a main thread cutter; s33, after the needle moves upwards and the standby needle moves upwards from the main thread cutter, the electric control unit controls the thread cutting driving source to act, the thread cutting driving source drives the main thread cutter to move, and the main thread cutter extracts at least one part of the upper thread end; and S34, the electronic control unit controls the sewing machine to start sewing the second needle, the third needle and the third needle until the Nth needle in the small-stitch sewing mode.
3. The bird nest thread cutting prevention method according to claim 2, wherein in the step S34, pre-drawing is performed after any one of the second needle, the third needle, and the Nth needle is sewn, the electric control unit controls the first thread loosening driving source to reset and controls the second thread loosening driving source to act so as to drive the main thread clamp to loosen threads and the thread clamp to clamp threads, and then, in the process of downwards moving and paying out the thread take-up lever, the electric control unit controls the thread tightening driving source to act so as to drive the thread plate to swing and wire, and the thread plate withdraws the upper thread so as to tighten the upper thread between the main thread clamp and the fabric; after the pre-drawing is finished, the electric control unit controls the first loose wire driving source to act and controls the second loose wire driving source to reset, so that the main wire clamp clamps wires and the wire bonding wire clamp loopers are driven to loose wires.
4. The method of claim 1 or 2, wherein in step S3, the absolute value of the current stitch length of the sewing machine is not more than 2.5mm when the sewing machine is operated in the small stitch length sewing mode.
5. The method of claim 1 or 2, wherein in step S3, the electronic control module controls the sewing machine to stitch the first needle to the Nth needle in a manner that the forward stitch and the backward stitch are switched.
6. The bird nest line shearing prevention method according to claim 1, wherein the wire bonding mechanism further comprises a fixedly arranged wire passing plate, the outer shell of the second loose wire driving source is fixedly connected with the wire passing plate, and a third wire passing hole, a fourth wire passing hole and a fifth wire passing hole are formed in the wire passing plate; along the axial direction of a main shaft in the sewing machine, the third wire through holes are distributed on one side of the wire bonding device, which is away from the main wire bonding device, and the fourth wire through holes and the fifth wire through holes are distributed on one side of the wire bonding device, which is facing the main wire bonding device; The third wire through holes are distributed on the upper side of the wire bonding device along the up-down direction, the fourth wire through holes and the fifth wire through holes are distributed on the lower side of the wire bonding device, and the second wire through holes are distributed between the fourth wire through holes and the fifth wire through holes; the upper thread in the sewing machine passes through the third thread passing hole, the thread-tying device, the fourth thread passing hole, the second thread passing hole, the fifth thread passing hole, the main thread-tying device and the first thread passing hole in sequence and then penetrates into a needle of the sewing machine.
7. The bird nest preventing and trimming method as claimed in claim 1, wherein the wire bonding mechanism further comprises a wire bonding connecting rod and a wire bonding driving shaft, the wire bonding connecting rod is installed in the sewing machine shell in a reciprocating manner, and the wire bonding driving source is connected with the wire bonding connecting rod and drives the wire bonding connecting rod to reciprocate; The wire bonding plate comprises a plate main body part, a first wire passing part, a first connecting plate and a second connecting plate, wherein the first wire passing part is bent and extended from the lower end of the plate main body part, the first connecting plate is extended from the side of the plate main body part, the second connecting plate is extended from the end part of the first connecting plate, the plate main body part is rotatably sleeved on a second wire loosening driving source, the plate main body part is parallel to the second connecting plate, two ends of a wire bonding driving shaft are respectively fixed on the plate main body part and the second connecting plate, and one end of the wire bonding connecting rod, which is far away from the wire bonding driving source, is rotatably sleeved on the wire bonding driving shaft.
8. The bird nest thread cutting prevention method according to claim 1, wherein the thread bonding mechanism further comprises a limit screw fixed to the first connecting plate; And the second connecting plate and the limit screw are closely arranged on two sides of the wire bonding connecting rod along the axial direction of the wire bonding driving shaft.
9. The bird nest thread cutting prevention method of claim 1, wherein the thread cutting driving source and the second thread loosening driving source are both electromagnets, and the thread cutting driving source and the second thread loosening driving source are fixedly installed on a sewing machine shell.
10. The method for preventing bird nest from trimming as claimed in claim 1, wherein in the step S1, a stitch length adjusting mechanism is further provided in the sewing machine, The needle distance adjusting mechanism comprises a needle distance adjusting driving source and a feeding mechanism connected between a main shaft and a tooth frame in the sewing machine, wherein the needle distance adjusting driving source is in transmission connection with a feeding transmission part for determining the needle distance of the sewing machine in the feeding mechanism, and the needle distance adjusting driving source is in communication connection with an electric control unit; In the step S3 and the step S6, the electronic control unit controls the output of the stitch adjusting driving source to enable the sewing machine to sew in the small-stitch sewing mode or enable the sewing machine to sew with the target stitch.

Description

Bird nest thread cutting prevention method based on small-gauge seam lifting and wire bonding linkage control Technical Field The invention relates to the technical field of sewing machines, in particular to a bird nest thread cutting prevention method based on small-gauge seam lifting and thread bonding linkage control. Background At present, a group of nest-shaped thread coils are formed on the reverse side of the seam of the fabric when the computer flat seaming machine is used for seam starting. Middle and high end clients and factories with certain requirements on sewing quality require that after sewing, thread heads of nest-shaped thread coils are cleaned, especially thin elastic material is taken as a main material, and the thinner the fabric is, the higher the sensitivity to the nest-shaped thread coils is. In this regard, some conventional sewing machines are equipped with a bird nest preventing thread cutting mechanism, which clamps the thread end of the upper thread on one side of the needle during the seam starting, and cuts the thread end after a preset number of needles (such as 2 needles or 3 needles) are subsequently sewn, thereby reducing bird nest-like thread coils accumulated on the fabric. Generally, the bird nest preventing thread cutting mechanism comprises a rotatable movable cutter, a thread cutting motor for driving the movable cutter to rotate, and a fixed cutter and a thread pressing plate which are fixedly arranged, wherein a seam lifting and thread hooking groove and a movable cutter cutting edge are arranged on the movable cutter, and a fixed cutter cutting edge is arranged on the fixed cutter. When the first needle of the sewing machine starts to move downwards, the thread cutting motor drives the movable knife to rotate, so that the thread starting and hooking groove on the movable knife rotates to the position right below the needle, the needle passes through the thread starting and hooking groove with an upper thread downwards, the upper thread end on one side of the needle is driven to the position below the movable knife under the action of the rotating shuttle, then the needle moves upwards to the position above the needle plate, the thread cutting motor drives the movable knife to rotate, the upper thread end is clamped between the movable knife and the thread pressing plate, the sewing machine continues to start to stitch for a set number of needles (such as 2 needles or 3 needles), the interweaving of a bottom thread and the upper thread is completed, the subsequent thread cutting is avoided, then the thread cutting motor drives the movable knife to continue to rotate, and the movable knife cutting edge of the movable knife is meshed with the fixed knife cutting edge of the fixed knife, and the thread end of the cut surface is shown in figure 1. As can be seen from fig. 1, after the upper thread ends are cut, the length of the bird nest residual thread ends remaining on the fabric=the thickness of the needle plate 10+the distance from the engagement position a of the movable knife 20 and the fixed knife 30 below the needle plate 10 to the needle hole 101 passing through the needle plate 10+the sewing distance L from the seam to the cut thread. The thickness of the needle plate 10 and the distance from the engagement position a between the movable knife 20 and the fixed knife 30 below the needle plate 10 to the needle passing hole 101 on the needle plate 10 are fixed by a mechanical structure, and the sewing distance L from the start of sewing to the cutting is determined by the number of sewing needles from the start of sewing to the cutting, for example, assuming that the sewing needle distance is 3mm, the sewing distance l=9mm from the start of sewing to the cutting after sewing 3 needles. It is apparent that the greater the number of sewing needles is, the greater the sewing distance L is, and the longer the length of the bird nest residual thread ends remains on the fabric. Therefore, when the existing bird nest preventing thread cutting mechanism is used for cutting threads in a seam starting mode, in order to avoid thread off after thread cutting, the threads can be cut at least after the second needle is used for realizing surface and bottom thread interweaving, and some thin sliding fabrics can be prevented from being off after thread cutting after at least three needles are sewn. Thus, when the thread ends are cut, the needle hole 101 on the needle plate 10 is relatively 2-3 pitches, and the residual thread ends of the bird nest on the fabric can be correspondingly lengthened by 2-3 pitches, so that the residual thread ends of the bird nest cannot be well shortened. Disclosure of Invention In view of the above-mentioned drawbacks of the prior art, the present invention aims to provide a bird nest thread trimming prevention method based on small-gauge seam lifting and wire bonding linkage control, which effectively shortens the length of residual bird nest th