JP2002119782A - Sewing thread twist-back preventer, sewing machine, two- needle sewing machine, and catch-stitching machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a sewing thread from being twisted back and loosened during the sewing operation such as back stitching, and to prevent any thread breakage or irregular stitch attributable to the loosening. SOLUTION: This sewing thread twist-back preventer comprises a re-twisting mechanism 12 for twisting the sewing thread 10 in the same direction as the twisting direction of the sewing thread to the sewing thread 10 which is drawn out of a bobbin 11 and leading to a sewing needle 4, a sewing direction detection part for detecting the sewing direction during the sewing operation, and a twist- back preventive means for driving the re-twisting mechanism 12 according to the result in detection of the sewing direction detection part. When the sewing direction detection part detects that the sewing direction is a predetermined one, the re-twisting mechanism 12 is driven, and the sewing thread 10 is continuously re-twisted in the same direction as the twisting direction. Twist-back and loosening of the sewing thread 10 during the sewing operation and thread breakage and irregular stitch of the sewing thread 10 attributable to the loosening can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing untwisting of a sewing thread in a sewing machine, a sewing machine provided with the untwisting device, and a two-needle sewing machine capable of preventing unwinding of a sewing thread.

[0002]

2. Description of the Related Art In sewing operations using a sewing machine, most of the so-called forward stitching, in which a sewing operation is performed while sending a cloth to a side (back side) away from an operator, is performed. Cannot be turned, or in the case of an electronic pattern stitch sewing machine, so-called backward stitching in which a sewing operation is performed while feeding a cloth to an operator side (front side) may be performed.

When both ends of a towel are simultaneously sewn with the left and right sewing machines as in an automatic towel sewing machine, the right sewing machine always performs forward sewing, while the left sewing machine always performs backward sewing.

[0004]

A sewing thread used to pass through a needle hole of a sewing needle is generally formed by twisting a plurality of threads. Then, in each sewing machine, when the sewing needle descends when the sewing needle pulls the sewing thread, and the sewing thread rubs against the edge portion of the needle hole of the sewing needle, the twist is performed in the same direction as the twisting direction of the sewing thread. A sewing thread is used that is twisted in the direction to be added.

[0005] For this reason, when the backward sewing is performed during the sewing operation using such a sewing thread, when the sewing thread rubs against the edge portion of the needle hole of the sewing needle when the sewing needle is lowered, the sewing thread is moved to the sewing thread. Is twisted in the direction opposite to the twisting direction (that is, the untwisting direction). In addition, the application of the twist in the twist return direction is continued while the backward stitching is being performed.

[0006] When a twist is applied to the sewing thread in the untwisting direction, the sewing thread is loosened for each thread forming the sewing thread, and the sewing thread is liable to be cut.
Seams are distorted.

In a two-needle sewing machine that performs double stitching, two rotary hooks disposed at positions facing two sewing needles are generally driven to rotate in the same direction. However, when the two rotary hooks are rotated in the same direction, in the sewing thread on the left side, the cloth feeding direction is opposite to the rotating direction of the rotary hook, which causes the seams to be jagged. Hitch stitches tend to occur, and the finished state of sewing decreases.

When the right rotary hook is rotated forward and the left rotary hook is rotated reversely, hitch stitch does not occur on the sewing thread on the left side. However, the sewing thread on the left side is twisted in the untwisting direction by rubbing against the blade point of the rotary hook and the needle hole of the sewing machine needle, and thread breakage and seam disorder are likely to occur due to the untwisting of the sewing thread. Become.

In a zigzag sewing machine that performs staggered sewing, sewing is performed while reciprocating a sewing needle to which a sewing thread is attached in a direction orthogonal to a cloth feeding direction. When the sewing thread is moved to, the sewing thread rubs against the blade point of the rotary hook or the needle hole of the sewing machine needle, so that twist is added in the direction of twisting return. .

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a sewing thread from being untwisted and loosened at the time of sewing work such as backward stitching, and to prevent thread breakage and seam disturbance caused by such loosening. It is to be.

Another object of the present invention is to improve the finished state of the double stitch by preventing the occurrence of hitch stitch and preventing the sewing thread from untwisting in a two-needle sewing machine performing double stitch.

Another object of the present invention is to prevent a sewing thread from being untwisted and loosened in a zigzag sewing machine that performs staggered sewing, and to prevent thread breakage and seam disturbance caused by such loosening. It is to be.

[0013]

According to a first aspect of the present invention, there is provided an apparatus for preventing untwisting of a sewing thread, wherein a sewing thread formed by twisting a plurality of threads is pulled out from a bobbin and is placed on a sewing thread path leading to a sewing needle. A twisting mechanism that is arranged and twists the sewing thread in the same direction as the direction in which the sewing thread is twisted, a sewing direction detection unit that detects a sewing direction during a sewing operation, and a detection result of the sewing direction detection unit. And a twist-return preventing means for driving the twist-adding mechanism accordingly.

Therefore, during the sewing operation, the sewing direction detecting section detects the sewing direction, and the sewing direction is a predetermined direction. Specifically, the sewing direction of the sewing operation is determined by the twist applied to the sewing thread during the sewing operation. If it is detected that the direction of returning the twist of the sewing thread is detected, the twist-resetting mechanism is driven by the untwist preventing means, and the twist is continuously applied to the sewing thread in the same direction as the twisting direction of the sewing thread.
For this reason, even when the sewing thread rubs against the edge of the needle hole of the sewing needle during the sewing operation and is twisted in the direction opposite to the twisting direction of the sewing thread (that is, in the direction of untwisting), the sewing thread is not twisted. Since the twist is applied in the same direction as the twisting direction of the sewing thread by the mechanism, the sewing thread is not loosened for each thread forming the sewing thread, and the twisted state is maintained. This prevents breakage of the thread and disturbance of the seam caused by the state where the sewing thread is loosened for each thread.

According to a second aspect of the present invention, in the apparatus for preventing untwisting of a sewing thread according to the first aspect, the twist adding mechanism includes a thread tensioner that clamps the sewing thread on the sewing thread path to apply tension, and A rotating body with a thread tensioner fixed,
And a drive unit for driving the rotating body to rotate.

Accordingly, the rotating body is driven to rotate by the drive of the driving unit, and the thread tensioner rotates integrally with the rotating body. At this time, twist is applied to the sewing thread held by the thread tensioner in the same direction as the direction in which the sewing thread is twisted.

According to a third aspect of the present invention, in the apparatus for preventing untwisting of the sewing thread according to the first aspect, the twisting mechanism opposes the outer peripheral surface by approaching the outer peripheral surface, and the sewing thread on the sewing thread path at the outer peripheral surface. And a drive unit for rotating the pair of disc-shaped rotating bodies in the same direction.

Accordingly, the pair of disk-shaped rotating bodies are driven to rotate in the same direction by the driving of the driving unit. At this time, the sewing thread held between the outer peripheral surfaces of these disk-shaped rotating bodies is Twisting is applied in the same direction as the twisting direction.

According to a fourth aspect of the present invention, in the apparatus for preventing untwisting of the sewing thread according to the first aspect, the twist adding mechanism includes a leaf spring, and the leaf spring, to which the leaf spring is attached, and which is provided on the sewing thread path. A leaf spring attachment body for sandwiching the sewing thread, and the leaf spring attachment body and the leaf spring in a direction in which twisting is applied to the sewing thread around a location where the sewing thread is sandwiched between the leaf spring attachment body and the leaf spring. And a drive unit for rotating the drive.

Therefore, the leaf spring mounting body and the leaf spring are integrally rotated by the driving of the driving portion, and the sewing direction of the sewing thread held between the leaf spring mounting body and the leaf spring is the same as that of the sewing thread. Twist is added in the direction. At this time, since the leaf spring mounting body and the leaf spring are driven to rotate so that the holding position of the sewing thread is substantially at the center, the centrifugal force is small even if centrifugal force acts on the leaf spring with the rotation. Value, the pressure for clamping the sewing thread by the leaf spring hardly changes, the sewing thread can be clamped with a stable force, and the twist can be stably added to the sewing thread.

[0021] The invention according to claim 5 is the invention according to claims 1 to 4.
In the apparatus for preventing untwisting of a sewing thread according to any one of the above, the twist adding mechanism is attached to a sewing machine main body.

Therefore, a new space for attaching the twisting mechanism to the conventional sewing machine is not required, and the twisting mechanism can be installed without increasing the size of the sewing machine.

According to a sixth aspect of the present invention, there is provided a sewing machine in which a sewing thread formed by twisting a plurality of threads and to which a sewing thread drawn from a bobbin is attached, and a bobbin around which a bobbin thread is wound are housed. A sewing thread having a rotary hook disposed at a position facing a tip of a sewing needle and capable of switching between forward sewing and backward sewing, wherein the device for preventing untwisting of a sewing thread according to any one of claims 1 to 4 is provided. Have.

Therefore, according to the sewing machine, it is possible to prevent the sewing thread from being untwisted at the time of backward stitching, and to prevent the thread breakage and the disorder of the seam caused by the sewing thread from being untwisted. Quality can be improved.

According to a seventh aspect of the present invention, there are provided two sewing needles which are arranged close to each other, are formed by twisting a plurality of threads, and are respectively attached with sewing threads drawn out from the bobbin, and a bobbin thread. The bobbin is stored at a position facing the tip of the sewing needle, and is rotatably driven in directions opposite to each other and along the cloth feeding direction.
In the two-needle sewing machine having two rotary hooks, one of the sewing threads is arranged on a sewing thread path from the thread winding to one of the sewing needles, and is arranged in the same direction as the sewing thread with respect to the sewing thread. It has a twist addition mechanism for adding twist.

Therefore, in a two-needle sewing machine that performs double stitching, generation of hitch stitches can be prevented by rotating the two rotary hooks in directions opposite to each other and along the direction in which the cloth is fed. Furthermore, at the time of sewing work, when one of the sewing threads is twisted in the reverse direction by rubbing against the sword tip of the rotary hook or by rubbing with the needle hole of the sewing machine needle, the twist is added to the sewing thread in the twisting direction by the twist adding mechanism. By adding, the return of twist of the sewing thread is prevented, and the breakage of the sewing thread and the disorder of the seam caused by the return of twist are prevented. Thereby, the finished state of the double stitch becomes very good.

[0027] The invention according to claim 8 is the second invention according to claim 7.
In the needle sewing machine, the twist adding mechanism includes a leaf spring,
A leaf spring attachment body to which the leaf spring is attached and which sandwiches the sewing thread on the sewing thread path by the leaf spring; and the sewing thread substantially centered on a position where the sewing thread is sandwiched by the leaf spring attachment body and the leaf spring. And a driving unit that rotationally drives the leaf spring mounting body and the leaf spring in a direction in which twist is applied to the plate spring.

Therefore, as described in the fourth aspect of the present invention, when twisting the sewing thread by rotating the leaf spring mounting body and the leaf spring, the leaf spring mounting body and the leaf spring have a position where the sewing thread is clamped. The centrifugal force acts on the leaf spring as it rotates, so that the centrifugal force is suppressed to a small value. Instead, the sewing thread can be clamped with a stable force, and twisting of the sewing thread can be stably performed.

According to a ninth aspect of the present invention, there is provided one sewing machine needle formed by twisting a plurality of threads and attaching a sewing thread drawn out from a bobbin, and the sewing machine needle in a direction orthogonal to a cloth feeding direction. A stitch sewing machine provided with a sewing needle reciprocating mechanism for reciprocating the sewing thread, the sewing thread is arranged on a sewing thread path from the thread winding to the sewing needle, and is in the same direction as the direction in which the sewing thread relies on the sewing thread. It has a twist addition mechanism for adding twist.

Therefore, when the sewing needle moves to one side during the staggered sewing, even if the sewing thread is rubbed against the blade point of the rotary hook or the needle hole of the sewing needle and twist is added in the twist return direction, the twist adding mechanism is used. By applying the twist in the twisting direction of the sewing thread, the untwisting of the sewing thread is prevented, and the thread breakage and the disorder of the seam due to the untwisting of the sewing thread do not occur.

According to a tenth aspect of the present invention, in the staggered sewing machine according to the ninth aspect, the twist adding mechanism comprises: a leaf spring;
A leaf spring attachment body to which the leaf spring is attached and which sandwiches the sewing thread on the sewing thread path by the leaf spring; and the sewing thread substantially centered on a position where the sewing thread is sandwiched by the leaf spring attachment body and the leaf spring. And a driving unit that rotationally drives the leaf spring mounting body and the leaf spring in a direction in which twist is applied to the plate spring.

Therefore, as described in the fourth aspect of the present invention, when twisting the sewing thread by rotating the leaf spring mounting body and the leaf spring, the leaf spring mounting body and the leaf spring have a position where the sewing thread is clamped. The centrifugal force acts on the leaf spring as it rotates, so that the centrifugal force is suppressed to a small value. Instead, the sewing thread can be clamped with a stable force, and twisting of the sewing thread can be stably performed.

[0033]

FIG. 1 shows a first embodiment of the present invention.
A description will be given with reference to FIG. FIG. 1 is a front view showing an attached state of the twist adding mechanism to the sewing machine, FIG. 2 is a perspective view showing the twist adding mechanism, FIG. 3 is a vertical sectional front view showing a part of the twist adding mechanism, and FIG. FIG.

As shown in FIG. 1, a sewing machine main body 2 and a mounting base 3 are fixed on the sewing machine base 1. The sewing machine main body 2 includes a sewing needle 4 that moves up and down, thread guide pieces 5, 6, 7,
A balance 8, a thread take-up spring 9, and the like are provided. A thread spool 11 around which a sewing thread 10 is wound and a twist adding mechanism 12 are attached to the mounting table 3. The twist adding mechanism 12 is a mechanism in which the sewing thread 10 pulled out from the bobbin 11 is arranged on a sewing thread path 13 reaching the sewing machine needle 4 and applies a twist to the sewing thread 10 in the same direction as the twisting direction of the sewing thread 10. .

A rotary hook (not shown) is arranged at a position below the sewing machine base 1 and opposite to the needle tip of the sewing needle 4, and a bobbin (a bobbin around which a bobbin thread is wound) is disposed in the rotary hook. (Not shown).

When the sewing operation is performed by setting the sewing thread 10 on the sewing machine, the sewing thread 10 is twisted by rubbing against the edge portion of the needle hole of the sewing needle 4. Here, the sewing thread 10 is formed by twisting a plurality of threads, and in a general sewing operation, the sewing thread 1 is used.
A sewing thread 10 is used in which the twisting direction of 0 and the twisting direction applied to the sewing thread 10 when rubbing against the edge portion of the needle hole of the sewing machine needle 4 during forward stitching are the same.

The twist adding mechanism 12 includes a motor 14 as a driving unit fixed to the mounting base 3, a first roller 16 fixed to a rotating shaft 15 of the motor 14 and driven to rotate, and an outer peripheral surface of the first roller 16 A second roller 17, which is a rotating body that is rotated by driving the first roller 16 in contact with the outer peripheral surface, a thread tensioner table 18 fixed to one side surface of the second roller 17, and a thread; It comprises a thread tensioner 19 attached to a tensioner table 18, a hollow shaft 20 fixed to the second roller 17 so as to extend to the other side of the second roller 17, and the like. The thread tension controller 19 is provided for the sewing thread path 1.
3 is a mechanism for sandwiching the upper sewing thread 10 and applying tension to the sewing thread 10.
2. It is constituted by a thread tension knob 23. The hollow shaft 20 is rotatably supported by the mounting base 3.

On the outer peripheral portion of the hollow shaft 20, a thread 11
Is detachably attached. The sewing thread 10 pulled out from the spool 11 is inserted into the hollow portion 2 in the hollow shaft 20.
0a, the hole 20a and the hole 18a are guided to the sewing machine main body 2 through a hole 18a formed in the thread tensioner table 18, and a part of the sewing thread path 13.

As shown in FIG. 4, this sewing machine has a CP
A control unit 24 having a microcomputer configuration including a U, a ROM, a RAM, and the like is provided. The control unit 24 includes a feed dog (see FIG. (Not shown) are connected, and a sewing direction detecting unit 26 for detecting a sewing direction at the time of sewing operation is connected.

The sewing direction detecting section 26 includes a proximity switch and a micro switch for detecting an operation position of a reverse feed lever (not shown) operated when performing reverse sewing, and a touch-back switch for operating during reverse sewing. For automatic thread trimmer sewing machines, a micro switch built into the touch back switch may be used, and for an automatic thread trimmer sewing machine with a back magnet operated at the time of automatic sewing, an electrical box that outputs a signal for controlling the back magnet may be used. it can. Then, when it is determined that the sewing direction at the time of the sewing operation is the backward sewing direction according to the detection result of the sewing direction detection unit 26, the motor 14 is driven (that is, the twist adding mechanism 12 is driven). Prevention means is control unit 2
4 functions.

In such a configuration, when the sewing operation is performed by setting the sewing thread 10 on the sewing machine and the sewing operation is performed by forward sewing, the motor 14 is not driven, and the twisting by the twist adding mechanism 12 is performed. Is not added.
During the forward stitching, when the sewing thread 10 rubs against the edge of the needle hole of the sewing machine needle 4, the sewing thread 10 is twisted in the twisting direction of the sewing thread 10. For this reason, at the time of the sewing operation of the forward stitching, the sewing thread 10 is not untwisted and is not loosened for each thread forming the sewing thread 10.

On the other hand, when the sewing direction detecting section 26 detects that the sewing direction is the backward sewing direction during the sewing operation,
The twisting mechanism 12 is driven based on the detection result. The driving operation of the twist adding mechanism 12 is as follows. First, the motor 14 is driven, and the first roller 16 is driven to rotate in the direction of the arrow (see FIG. 2) with the driving of the motor 14.
The second roller 17 is brought into contact with the outer peripheral surface of the roller 16 in the direction of the arrow, and the thread tensioner table 18 and the thread tensioner 19 are rotated integrally with the second roller 17. The thread tensioner 19 holds the sewing thread 10 pulled out from the bobbin 11 and guided to the sewing needle 4. The thread tensioner 19 is rotated in the direction of the arrow while holding the sewing thread 10, so that the sewing thread 10 is held. The twist is continued to be added. The direction of twist applied to the sewing thread 10 by the twist adding mechanism 12 is the same as the direction in which the sewing thread 10 is twisted.

For this reason, during the sewing operation in the backward sewing direction, the sewing thread 10 is continuously twisted by the twist adding mechanism 12 in the same direction as the direction in which the sewing thread 10 is twisted. Even if the edges of the needle holes are rubbed against each other and twisted in the direction opposite to the direction in which the sewing thread 10 is twisted (twist return direction), the two twists in the opposite directions are canceled out. Therefore, by driving the twisting mechanism 12 during the sewing operation in the backward stitching, the sewing thread 10 is not loosened for each thread forming the sewing thread 10 and the twisted state is maintained. Thereby, even at the time of the sewing operation in the reverse stitching, the thread breakage and the disorder of the seam caused by the loosening of the sewing thread 10 for each thread can be prevented.

Next, a second embodiment of the present invention will be described with reference to FIG.
7 will be described with reference to FIG. 1 to 4
The same parts as those described in are described by the same reference numerals, and the description thereof will be omitted (the same applies to the following embodiments).

In this embodiment, a twisting mechanism 27 having a structure different from that described in the first embodiment is provided. The twist adding mechanism 27 includes a pair of rollers 28 and 29, which are a pair of disk-shaped rotating bodies, and a pair of these rollers 2.
Power transmission roller 30 whose outer peripheral surface is in contact with 8, 29
And a motor 31 which is a driving unit.
The roller 28 is fixed to the rotation shaft 32 of the motor 31, and the outer peripheral surface of the roller 28 and the outer peripheral surface of the roller 29 are opposed to each other with a predetermined dimension “A” (see FIG. 7).
The sewing thread 10 pulled out from the roller 1
The thread guide piece 33 located between the outer peripheral surfaces of the
It is fixed to.

The motor 31 is fixed to a motor mount 34, and the motor mount 34 is screwed to the mount 3 so as to be adjustable in position. By adjusting the screw fixing position of the motor mount 34, the distance "A" between the outer peripheral surfaces of the rollers 28 and 29 can be adjusted.

In such a configuration, when the sewing operation is performed by setting the sewing thread 10 on the sewing machine, and the sewing operation is performed by the forward stitching, the motor 31 is not driven, and the twisting by the twist adding mechanism 27 is performed. No addition is made.

On the other hand, when the sewing direction detecting section 26 (see FIG. 4) detects that the sewing direction is the backward sewing direction during the sewing operation, the twist adding mechanism 27 is operated based on the detection result.
Is driven. In the driving operation of the twist adding mechanism 27, first, the motor 31 is driven, and the roller 28 is driven to rotate in the direction of the arrow (see FIG. 6) with the driving of the motor 31, and the power transmission roller 30 and the roller 29 are further driven. Are rotated in the directions indicated by the arrows. When the rollers 28 and 29 are driven to rotate in the same direction, twist is applied to the sewing thread 10 held between the outer peripheral surfaces of the rollers 28 and 29 in the direction indicated by the arrow (see FIG. 7). . The direction of twist applied to the sewing thread 10 by the twist adding mechanism 27 is the same as the direction in which the sewing thread 10 is twisted.

For this reason, during the sewing operation in the backward sewing direction, twisting is continuously applied to the sewing thread 10 by the twist adding mechanism 27 in the same direction as the twisting direction of the sewing thread 10, so that the sewing thread 10 is Even if the edges of the needle holes are rubbed against each other and twisted in the direction opposite to the direction in which the sewing thread 10 is twisted (twist return direction), the two twists in the opposite directions are canceled out. Therefore, by driving the twisting mechanism 12 during the sewing operation in the backward stitching, the sewing thread 10 is not loosened for each thread forming the sewing thread 10 and the twisted state is maintained. Thereby, even at the time of the sewing operation in the reverse stitching, the thread breakage and the disorder of the seam caused by the loosening of the sewing thread 10 for each thread can be prevented.

When the sewing thread 10 to be used is replaced with a thread having a different diameter, the distance "A" between the outer peripheral surfaces of the rollers 28 and 29 is adjusted by adjusting the screwing position of the motor mount 34 to the mount 3. Is adjusted to be approximately the same size as the diameter of the sewing thread 10 to be used. By this adjustment, even if the diameter of the sewing thread 10 changes, the sewing thread 10 is
29, the twist can be reliably added to the sewing thread 10 by the twist adding mechanism 27.

Next, a third embodiment of the present invention will be described with reference to FIG.
It will be described based on. The basic structure of the present embodiment is the first
Is the same as that of the embodiment of FIG.
Mounting structure. The peg 11 is attached to the mount 3 via a thrust bearing 35.

Thus, the sewing thread 10 from the thread spool 11 is
The resistance at the time of pulling out the sewing thread 10 is reduced, and the pulling out of the sewing thread 10 is performed smoothly.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
It will be described based on. The basic structure of the present embodiment is the first
This embodiment is the same as the above-described embodiment, except that the twisting mechanism 12 and the bobbin 11 are attached to the sewing machine main body 2.

In such a configuration, the twisting mechanism 1
There is no need to provide a space on the sewing machine stand 1 for attaching the spool 2 and the bobbin 11, and the twisting mechanism 12 can be installed without increasing the size of the sewing machine.

In each of the embodiments described above, the case has been described in which the twisting mechanisms 12 and 27 are driven at the time of backward sewing using the sewing thread 10 corresponding to forward sewing.
In the case where a thread for a knitting machine having a large number of reverse twists is used in a sewing machine, if the twisting mechanism 12, 27 is set to be driven at the time of forward sewing, the reverse twisted yarn for a knitting machine is used in the sewing machine. This also prevents the thread from being untwisted at the time of forward sewing, thereby expanding the range of thread types that can be used in the sewing machine.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. In the present embodiment, the twist adding mechanism 36 is attached to the sewing machine main body 2. The twist adding mechanism 36 includes a leaf spring 37, a leaf spring mounting body 39 to which the leaf spring 37 is fixed by screws 38 a and 38 b, a rotating disk 40 to which the leaf spring mounting body 39 is fixed, a motor 41 as a driving unit, and a motor 41. Are transmitted to the rotary disk 40.

The leaf spring 37 and the leaf spring mounting body 39 hold the sewing thread 10 which is pulled out from a thread winding (not shown) and reaches the sewing needle 4. By adjusting the amount of tightening of the screw 38a, the force for clamping the sewing thread 10 between the leaf spring 37 and the leaf spring mounting body 39 can be adjusted.

The sewing thread 10 pulled out from the thread winding (not shown) is inserted into the hollow hole 43b of the rotating shaft 43a of the gear 43, and the sewing thread 10 coming out of the hollow hole 43b is inserted from the lower side of the leaf spring mounting body 39. The second formed on the leaf spring mounting body 39
After passing through the hole 39b, the upper side of the leaf spring mounting body 39 (the leaf spring 3
7), passes through a holding portion formed by the leaf spring 37 and the leaf spring mounting body 39, passes through the first hole 39a, and is passed below the leaf spring mounting body 39.

When the driving force of the motor 41 is transmitted to the rotating disk 40, the rotating disk 40, the leaf spring mounting body 39 and the leaf spring 3
7 rotate together. This rotation is performed by the leaf spring mounting body 39.
The sewing is performed in a direction in which twist is applied to the sewing thread 10 with the position where the sewing thread 10 is sandwiched between the sewing thread 10 and the leaf spring 37 substantially at the center.

The sewing thread 10 drawn from the thread spool
On the sewing thread path 13 leading to the sewing needle 4, in addition to the twisting mechanism 36, a first thread tensioner 44, a second thread tensioner 45,
A balance 8 and the like are arranged.

In such a configuration, the motor 41 is not driven when the forward sewing operation is being performed.
The twisting mechanism 36 is not driven. When the sewing direction detecting unit 26 (see FIG. 4) detects that the sewing operation has been set in the backward stitching state, the motor 41 is driven, and the twist adding mechanism 36 is driven.

When the twisting mechanism 36 is driven, the motor 4
By the drive of 1, the rotating disk 40, the leaf spring mounting body 39, and the leaf spring 37 rotate integrally in the manner indicated by the arrow in FIG. 11, and are held between the leaf spring 37 and the leaf spring mounting body 39 of the sewing thread 10. At a portion passing through the needle hole of the sewing machine needle 4 from the portion, twist is applied in the twist direction of the sewing thread 10.

Therefore, as in the above-described embodiments, during the sewing operation in the backward sewing direction, the twisting mechanism 36 twists the sewing thread 10 in the same direction as the twisting direction of the sewing thread 10. Therefore, even if the sewing thread 10 rubs against the edge portion of the needle hole of the sewing needle 4 and is twisted in a direction opposite to the twisting direction (twist return direction) of the sewing thread 10, the two threads are opposite to each other. The twist in the direction is canceled out. Accordingly, by driving the twisting mechanism 36 during the sewing operation in the backward stitching, the sewing thread 10 is not unraveled for each thread forming the sewing thread 10 and the twisted state is maintained. Thereby, even at the time of the sewing operation in the reverse stitching, the thread breakage and the disorder of the seam caused by the loosening of the sewing thread 10 for each thread can be prevented.

Further, in the twist adding mechanism 36 of the present embodiment, the leaf spring mounting body 39 and the leaf spring 37 are driven to rotate so that the holding position of the sewing thread 10 is substantially at the center. Even if the centrifugal force acts on the leaf spring 37, the centrifugal force is suppressed to a small value, so that the pressure for clamping the sewing thread 10 by the leaf spring 37 hardly changes. Therefore, even when the twisting mechanism 36 is driven, the sewing thread 1
0 can be pinched with a stable force, the sewing thread 10 is prevented from slipping between the leaf spring attachment body 39 and the leaf spring 37, and the twist can be stably added to the sewing thread 10 and, as a result, In addition, the twist can be stably added to the sewing thread 10.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
3 will be described. Twist adding mechanism 3 of the present embodiment
The basic structure of 6a is the same as that of the fifth embodiment,
The different point is that the thread take-up spring 46 and the thread take-up spring guide 47 are attached to the leaf spring attachment 39.

Therefore, also in the present embodiment, substantially the same operations and effects as in the fifth embodiment can be obtained.

Next, a seventh embodiment of the present invention will be described with reference to FIG.
4 will be described. In the present embodiment, a twisting mechanism 12 is attached to the sewing machine main body 2 in the same manner as in the fourth embodiment shown in FIG. However, the mounting direction of the thread tensioner 19, which is a component of the twist adding mechanism 12, is changed. When the thread tensioner 19 is driven to rotate in the direction indicated by the arrow, the thread tension spring 22 is placed on the center of rotation. The center is located.

Therefore, when the thread tensioner 19 is driven to rotate in the direction of the arrow to twist the sewing thread 10, even if a centrifugal force acts on the thread tension spring 22 with the rotation,
The direction of action of the centrifugal force does not coincide with the direction in which the thread tension disc 21 can move, and the tension applied to the sewing thread 10 by the thread tensioner 19 hardly changes, so that a stable tension can be applied to the sewing thread 10. it can. For this reason, it is prevented that the stitches of the sewing thread 10 are disturbed due to the loosened state of the sewing thread 10. Further, since the sewing thread 10 is securely held by the thread tensioner 19 when the twisting mechanism 12 is driven, twisting of the sewing thread 10 can be stably performed.

Next, an eighth embodiment of the present invention will be described with reference to FIG.
5 will be described. This embodiment is different from the fifth embodiment described with reference to FIGS.
Is provided on a two-needle sewing machine.

The two-needle sewing machine is a sewing machine used for double stitching.
a, 48b and two rotary hooks (not shown) arranged at positions facing the needle tips of the two sewing needles 48a, 48b. A bobbin (not shown) around which a bobbin thread is wound is accommodated in the rotary hook. One (left) rotary hook is driven to rotate in the reverse direction, and the other (right) rotary hook is driven in the normal direction. The rotary kettle is driven to rotate, and both rotary hooks are driven to rotate in the direction along the cloth feeding direction. The directions of the two rotary hooks may be horizontal or vertical.

The two-needle sewing machine has one sewing needle 4
Two threads, a sewing thread 10a attached to the sewing machine needle 8b and a sewing thread 10b attached to the other sewing needle 48b, are used, and two thread windings (not shown) are used.

The twist adding mechanism 36 is connected to one of the sewing threads 10a.
Are arranged on the sewing thread path 13a. As described above, the twist adding mechanism 36 includes the leaf spring 37 and the leaf spring mounting body 3.
9, a rotating disk 40, a motor 41, gears 42 and 43, and the like. The motor 41 is configured to be rotationally driven at the same time as the sewing operation is started.

The other sewing thread 10b is attached to the sewing needle 48b via the first thread tensioner 49, the second thread tensioner 50, the balance 8 and the like arranged on the sewing thread path 13b after being pulled out from the bobbin. I have.

In such a configuration, in the twin-needle sewing machine according to the present embodiment, the one (left) rotary hook is driven to rotate in the reverse direction, so that the occurrence of hitch stitch of the left sewing thread 10a is prevented. . Further, the sewing thread 10a attached to the one (left) sewing needle 48a is twisted in the untwisting direction by rubbing against the sword tip of the rotary hook and the needle hole of the sewing needle 48a. The twist is added in the same direction as the twisting direction by the twist adding mechanism 36. For this reason, a twist in the opposite direction (twist return direction) to the twisting direction of the sewing thread 10a added to the sewing thread 10a by rubbing against the blade point of the rotary hook or the needle hole of the sewing needle 48a, and the twist is added by the twist adding mechanism 36. The twist in the same direction as the twist direction of the sewing thread 10a is canceled out. Therefore, the sewing thread 10a is not loosened during the double-stitch sewing operation, so that thread breakage and seam distortion do not occur.

The sewing thread 10b attached to the sewing needle 48b is twisted in the twisting direction of the sewing thread 10b when the sewing thread 10b rubs against the blade point of the rotary hook or the needle hole of the sewing needle 48b. No problem of untwisting occurs.

Thus, in the two-needle sewing machine, the occurrence of hitch stitches is prevented, and the occurrence of thread breakage and disturbance of the seam due to untwisting of the sewing threads 10a and 10b during the sewing operation is prevented. The finished condition of the stitch becomes very good.

Next, a ninth embodiment of the present invention will be described with reference to FIG.
6 will be described. The present embodiment is provided with a twisting mechanism described in each of the above-described embodiments with respect to a zigzag sewing machine capable of performing zigzag stitching. The details of the structure of the zigzag sewing machine are omitted, and The structure of the mechanism will be described with reference to the drawings of the above embodiments. FIG. 16 is an explanatory diagram showing the stitches of the zigzag stitch by the zigzag sewing machine.

The staggered sewing machine according to the present embodiment includes one sewing needle formed by twisting a plurality of threads and to which a sewing thread drawn from a bobbin is attached, and a sewing machine in a direction orthogonal to a cloth feeding direction. A sewing needle reciprocating mechanism for reciprocating the needle is provided. Furthermore, the twisting mechanism 3 described in the fifth embodiment (see FIGS. 10 to 12)
6 are provided.

When the zigzag stitch is performed by the zigzag sewing machine, the stitches are as shown in FIG. 16. When the zigzag stitch is performed while the sewing machine needle moves in one direction,
For example, when the stitch indicated by A in FIG. 16 is formed, the sewing thread 10 rubs against the blade point of the rotary hook and the needle hole of the sewing machine needle, so that twist is applied in the untwisting direction.

However, since the twisting mechanism 36 is provided in the staggered sewing machine, the twisting mechanism 36 can twist the sewing thread 10 in the twisting direction, thereby preventing the sewing thread 10 from untwisting. As a result, thread breakage and stitch disturbance due to untwisting of the sewing thread 10 do not occur.

In such a staggered sewing machine, when the stitch indicated by A is formed, a force in the direction in which the sewing thread 10 is untwisted acts, and when the stitch indicated by B is formed, the twist is returned to the sewing thread 10. No direction force acts. Therefore, the motor 41 of the twist adding mechanism 36 may be driven when the seam A is formed, and the motor 41 may be stopped when the seam B is formed.
The motor 41 may be constantly driven so that the sewing thread 10 is always twisted in the twisting direction.

[0082]

According to the apparatus for preventing untwisting of a sewing thread according to the first aspect of the present invention, the sewing direction at the time of the sewing operation is a direction in which a twist in the untwisting direction is applied to the sewing thread formed by twisting. If this is detected by the sewing direction detection unit, the twist adding mechanism is driven by the untwist preventing means based on the detection result, and the twist is continuously applied to the sewing thread in the same direction as the sewing direction of the sewing thread. Accordingly, it is possible to prevent the sewing thread from being untwisted and loosened for each of the threads forming the sewing thread during the sewing operation, and the breakage of the sewing thread or the seam generated due to such loosening can be prevented. Disturbance can be prevented.

According to the second aspect of the present invention, in the apparatus for preventing untwisting of a sewing thread according to the first aspect, the twist adding mechanism includes a thread tensioner that clamps a sewing thread on a sewing thread path to apply tension, and a thread tensioner. Since the rotating body has a fixed rotating body and a driving unit for driving the rotating body to rotate, the driving unit drives the rotating body to rotate, and the thread tensioner is rotated integrally with the rotating body. A twist can be applied to the sewing thread held by the thread tensioner in the same direction as the direction in which the sewing thread is twisted.

According to the third aspect of the present invention, in the apparatus for preventing untwisting of a sewing thread according to the first aspect, the twist adding mechanism opposes the outer peripheral surface by approaching the outer peripheral surface, and uses the outer peripheral surface to remove the sewing thread on the sewing thread path. Since it has a pair of disk-shaped rotating bodies to be sandwiched and a driving unit that drives the pair of disk-shaped rotating bodies to rotate in the same direction, the pair of disk-shaped rotating bodies are driven to rotate in the same direction by driving the driving unit. At this time, a twist can be applied to the sewing thread sandwiched between the outer peripheral surfaces of the disc-shaped rotating bodies in the same direction as the twisting direction of the sewing thread.

According to a fourth aspect of the present invention, in the apparatus for preventing untwisting of a sewing thread according to the first aspect, the twist adding mechanism includes a leaf spring, and a leaf spring to which the leaf spring is attached. A leaf spring mounting body for holding the sewing thread,
A driving unit for rotating the leaf spring mounting body and the leaf spring in a direction in which twist is applied to the sewing thread with the leaf spring mounting body and the leaf spring sandwiching the sewing thread substantially at the center is provided. The attachment body and the leaf spring can be integrally driven to rotate, and twist can be applied to the sewing thread sandwiched between the leaf spring attachment body and the leaf spring in the same direction as the twisting direction of the sewing thread. Furthermore, since the leaf spring mounting body and the leaf spring are driven to rotate so that the position where the sewing thread is held is substantially at the center, even if centrifugal force acts on the leaf spring with the rotation, the value can be suppressed to a small value. Thus, the sewing thread can be held with a stable force without substantially changing the pressure for holding the sewing thread by the leaf spring, and twisting can be stably applied to the sewing thread.

According to the invention described in claim 5, in the apparatus for preventing untwisting of a sewing thread according to any one of claims 1 to 4, the twist adding mechanism is attached to the sewing machine main body. On the other hand, a new space for mounting the twisting mechanism is not required, and the twisting mechanism can be installed without increasing the size of the sewing machine.

According to the sewing machine of the sixth aspect of the present invention, the sewing machine which can be switched between forward sewing and reverse sewing has the device for preventing the sewing thread from untwisting back according to any one of the first to fourth aspects. The sewing thread can be prevented from being untwisted at the time of sewing, and thread breakage or stitch failure caused by the sewing thread being untwisted can be prevented, and the quality of the sewing operation can be improved.

According to the two-needle sewing machine according to the seventh aspect of the present invention, hitch stitches can be prevented by rotating the two rotary hooks in directions opposite to each other and along the cloth feeding direction. Further, even if one of the sewing threads is twisted in the reverse direction by rotating the two rotary hooks in directions opposite to each other, the twist is added to the sewing thread in the twist direction by the twist adding mechanism. The sewing thread can be prevented from untwisting, and the sewing thread can be prevented from being broken or the seam disturbed due to untwisting, and the finished state of the double stitch, which is a sewing operation using a two-needle sewing machine, can be improved. Can be.

According to the eighth aspect of the present invention, in the two-needle sewing machine according to the seventh aspect, the twist adding mechanism includes a leaf spring and a leaf spring to which the leaf spring is attached, and the sewing thread on the sewing thread path is moved by the leaf spring. It has a leaf spring mounting body to be clamped, and a drive unit for rotating and driving the leaf spring mounting body and the leaf spring in a direction in which twist is applied to the sewing thread with the sewing thread sandwiched by the leaf spring mounting body and the leaf spring being substantially at the center. By driving the driving unit, the leaf spring mounting body and the leaf spring are integrally driven to rotate, and the sewing thread held between the leaf spring mounting body and the leaf spring is twisted in the same direction as the twisting direction of the sewing thread. Can be added. Furthermore, since the leaf spring mounting body and the leaf spring are driven to rotate so that the position where the sewing thread is held is substantially at the center, even if centrifugal force acts on the leaf spring with the rotation, the value can be suppressed to a small value. Thus, the sewing thread can be held with a stable force without substantially changing the pressure for holding the sewing thread by the leaf spring, and twisting can be stably applied to the sewing thread.

According to the staggered sewing machine according to the ninth aspect of the present invention, when the sewing needle moves to one side during the staggered sewing,
Even if the thread is twisted in the untwisting direction by rubbing against the needle point of the rotary hook or the needle hole of the sewing needle, the twisting mechanism prevents the thread from untwisting by adding the twist in the twisting direction. It is possible to prevent breakage of the thread and disturbance of the seam due to the untwisting of the sewing thread, and it is possible to perform a staggered sewing with a good finished state.

According to the tenth aspect, the ninth aspect is provided.
In the staggered sewing machine described above, the twist adding mechanism includes a leaf spring, a leaf spring attachment body to which the leaf spring is attached, and the leaf spring is used to clamp the sewing thread on the sewing thread path, the leaf spring attachment body, and the leaf spring. Since the leaf spring mounting body and the driving unit that rotationally drives the leaf spring in a direction in which twist is applied to the sewing thread about the center of the sewing thread held by the spring, the leaf spring mounting body is driven by driving the driving unit. The plate spring and the plate spring are integrally rotated to apply a twist to the sewing thread held between the plate spring mounting body and the plate spring in the same direction as the direction in which the sewing thread is twisted. Furthermore, since the leaf spring mounting body and the leaf spring are driven to rotate so that the position where the sewing thread is held is substantially at the center, even if centrifugal force acts on the leaf spring with the rotation, the value can be suppressed to a small value. Thus, the sewing thread can be held with a stable force without substantially changing the pressure for holding the sewing thread by the leaf spring, and twisting can be stably applied to the sewing thread.

[Brief description of the drawings]

FIG. 1 is a front view showing an attached state of a twist adding mechanism to a sewing machine according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a twisting mechanism.

FIG. 3 is a vertical sectional front view showing a part of a twisting mechanism.

FIG. 4 is a block diagram showing a control structure of the sewing machine.

FIG. 5 is a front view showing an attached state of a twist adding mechanism to a sewing machine according to a second embodiment of the present invention.

FIG. 6 is a side view thereof.

FIG. 7 is an explanatory diagram illustrating a state in which twist is applied to a sewing thread.

FIG. 8 is a front view showing an attached state of a twist adding mechanism to a sewing machine according to a third embodiment of the present invention.

FIG. 9 is a front view showing an attached state of a twisting mechanism to a sewing machine according to a fourth embodiment of the present invention.

FIG. 10 is a front view showing an attached state of a twisting mechanism to a sewing machine according to a fifth embodiment of the present invention.

FIG. 11 is a perspective view showing a twisting mechanism.

FIG. 12 is a side view showing a twisting mechanism.

FIG. 13 is a perspective view showing a twisting mechanism according to a sixth embodiment of the present invention.

FIG. 14 is a front view showing a twisting mechanism according to a seventh embodiment of the present invention.

FIG. 15 is a front view showing a part of a two-needle sewing machine according to an eighth embodiment of the present invention.

FIG. 16 is an explanatory view showing a staggered stitch by a staggered sewing machine according to a ninth embodiment of the present invention.

[Explanation of symbols]

 2 Sewing machine body 4 Sewing needle 10 Sewing thread 10a, 10b Sewing thread 11 Thread winding 12, 27, 36, 36a Twist adding mechanism 13 Sewing thread path 13a Sewing thread path 14 Driving unit 17 Rotating body 19 Thread tensioner 26 Sewing direction detecting unit 28, 29 Disc-shaped rotating body 31 Drive unit 37 Leaf spring 39 Leaf spring mounting body 41 Drive unit 48a, 48b Sewing needle

Claims (10)

[Claims] A sewing thread formed by twisting a plurality of threads is drawn out of a bobbin and arranged on a sewing thread path leading to a sewing needle, and is twisted with respect to the sewing thread in the same direction as the twisting direction of the sewing thread. A twist adding mechanism, a sewing direction detecting unit that detects a sewing direction at the time of sewing work, and a twist return preventing unit that drives the twist adding mechanism according to a detection result of the sewing direction detecting unit. Characteristic device to prevent untwisting of sewing thread. 2. The twisting mechanism includes: a thread tensioner that clamps the sewing thread on the sewing thread path to apply tension; a rotating body to which the thread tensioner is fixed; and a drive that rotationally drives the rotating body. The device for preventing untwisting of a sewing thread according to claim 1, further comprising: 3. The twist adding mechanism comprises: a pair of disk-shaped rotating bodies that oppose each other with an outer peripheral surface thereof close to and sandwich the sewing thread on the sewing thread path at the outer peripheral surface; and a pair of the disk-shaped rotating bodies. The device according to claim 1, further comprising a driving unit configured to rotate in the same direction. 4. The twist adding mechanism includes: a leaf spring; a leaf spring attached body to which the leaf spring is attached, and which sandwiches the sewing thread on the sewing thread path by the leaf spring; 2. A drive unit for rotating the leaf spring mounting body and the leaf spring in a direction in which twist is applied to the sewing thread about a position where the sewing thread is sandwiched by the leaf spring. Device for preventing the sewing thread from untwisting. 5. The apparatus for preventing untwisting of a sewing thread according to claim 1, wherein the twisting mechanism is attached to a sewing machine main body. 6. A single sewing needle formed by twisting a plurality of threads and attached with a sewing thread drawn out from a bobbin, and a bobbin around which a lower thread is wound are housed to face the tip of the sewing needle. A sewing machine having a rotary hook disposed at a position where the sewing thread can be switched between forward sewing and backward sewing. The sewing machine according to any one of claims 1 to 4, further comprising: sewing machine. 7. A bobbin wound with a bobbin around which two sewing needles, which are arranged close to each other, are formed by twisting a plurality of threads, and each of which is attached with a sewing thread drawn from a bobbin, and a bobbin thread are wound. A rotary hook that is disposed at a position facing the tip of the sewing needle and that is driven to rotate in a direction opposite to a direction along the cloth feeding direction. A two-needle sewing machine having a twisting mechanism disposed on a sewing thread path from the thread winding to one of the sewing needles and applying a twist to the sewing thread in the same direction as the twisting direction of the sewing thread. . 8. The twist adding mechanism includes: a leaf spring; a leaf spring attached body to which the leaf spring is attached and which sandwiches the sewing thread on the sewing thread path by the leaf spring; 8. A driving unit for rotating the leaf spring mounting body and the leaf spring in a direction in which twisting is applied to the sewing thread about a position where the sewing thread is sandwiched by the leaf spring. 2-needle sewing machine. 9. A sewing machine needle formed by twisting a plurality of threads and attaching a sewing thread drawn out from a bobbin, and a sewing machine needle for reciprocating the sewing machine needle in a direction orthogonal to a cloth feeding direction. A staggered sewing machine provided with a reciprocating mechanism, wherein the sewing thread is arranged on a sewing thread path from the bobbin winding to the sewing machine needle, and twists the sewing thread in the same direction as the direction in which the sewing thread is joined. A staggered sewing machine characterized by having: 10. The leaf twisting mechanism includes: a leaf spring; a leaf spring attached body to which the leaf spring is attached, and which sandwiches the sewing thread on the sewing thread path by the leaf spring; 10. A driving unit for rotating the leaf spring mounting body and the leaf spring in a direction in which twist is applied to the sewing thread about a position where the sewing thread is sandwiched by the leaf spring. Staggered sewing machine.