JPH0263036B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an empty ring sewing device for an overlock sewing machine which is capable of automatically cutting an empty ring.

Generally, when overlocking the edge of a fabric with an overlock sewing machine, when the sewing is completed, a hollow loop is created that connects the fabric. For this reason, conventional overlock sewing machines are equipped with an empty ring holding/cutting device that is integrated with a cutting blade and a clamping member made of an elastic material on the front side of the needle drop, so that when sewing is completed, The worker brings the empty ring along with the fabric to the front side, presses it against the cutting blade, uses the cutting edge to cut it, and then holds the cut end of the cut ring with a holding member to remove the empty ring left on the sewing machine side. By holding this ring on the upper surface of the throat plate and sewing this empty ring into the seam of the next fabric, it is possible to prevent the seam from fraying at the beginning of sewing without special bar-tacking work. There is.

By the way, the above-mentioned hollow ring is usually composed of one or two needle threads and two looper threads, and when cutting the hollow ring, each thread making up the hollow ring is cut at the same time. It is preferable that the shape of the hollow ring is maintained uniformly even at the cut end.

However, with the conventional method of cutting the hollow ring by pressing it against the cutting blade, the threads that make up the hollow ring may not be cut at the same time due to the operator's carelessness, resulting in one or two threads being thin. The tail may be cut unevenly.

This seems to occur because the empty ring unravels during cutting.

Therefore, if such unevenly cut hollow rings are sewn into the seam of the next fabric, not only will the aesthetic appearance of the seam be damaged, but some of the hollow rings with thin tails will be sewn. There is sufficient fraying, such as protruding from the eye, or an empty ring sewn into the seam that is not sufficiently caught between the seams and easily comes out from the end of the seam when pulled. There were cases where the stop function could not be obtained.

It seems that such a problem can be solved by shearing the empty ring with a pair of blades like scissors.
In some cases, an empty ring is inserted between the fixed blade and the movable blade, and the movable blade is driven by a driving means such as a solenoid to cut the blade. However, this type of device requires an operation switch to energize the solenoid and start the cutting operation, and the operator has to operate this operation switch at an appropriate time, which is cumbersome. was.

Furthermore, among conventional products of this type, there is a method in which the cut end of the cut empty ring is clamped by a clamping means driven by a driving means such as an electromagnetic solenoid, but the timing for releasing the clamp is If setting is difficult and the empty ring is released too quickly, it may not be sewn into the seam sufficiently and a portion of the empty ring may remain protruding from the sewing start. On the other hand, if the opening of the loop is slow, there may be a problem in that the sewing start end of the fabric is pulled through the clamped loop during the sewing of the loop.

The present invention was made based on the above circumstances, and although its purpose is to shear the hollow rings formed in a continuous manner on the fabric at once like scissors, it is not necessary to drive the movable blade. There is no need to worry about operating a switch, etc., and the empty ring can be cut automatically, and the empty ring held by the empty ring holding means can be cut at an appropriate timing while the empty ring is being sewn into the seam. This prevents a part of the empty ring from remaining in a protruding state at the end of the sewing start, and also prevents the fabric from being pulled through the clamped empty ring. To provide an empty ring sewing device for an overlock sewing machine, which can shorten the empty ring left at the rear end of the fabric after cutting the empty ring without any risk, and can even the length of the empty ring remaining on the sewing machine side to a constant length. It provides:

The present invention has been made in view of the above-mentioned circumstances.The present invention has been made in view of the above-mentioned circumstances. In an overlock sewing machine, the empty ring on the side connected to the needle is held by an empty ring holding means in front of the sewing machine, and the held empty ring is gradually fed out and sewn into the sewing start end of the fabric to be newly sewn. The ring sewing device includes: a driving means for driving a movable blade of the ring cutter; and a ring holding means for elastically pressing and holding the ring cut by the ring cutter; A sensor that detects objects passing near the needle drop, a rotary pulse generator that generates needle movement pulses in synchronization with the needle movement of the sewing machine, and a predetermined number of counts of the needle movement pulses from the time when the sensor detects the end of the fabric. a second delay operation means that outputs a stop signal to the sewing machine motor when the sensor detects an empty ring;
The present invention is characterized by comprising a delay operation means, and the following.

In the above-described empty chain sewing device for an overlock sewing machine, the sewing machine motor can be stopped when a predetermined number of needle movement pulses have been counted after the sensor detects the end of the fabric. The continuous empty rings can be made to have a constant length. Further, when the operator moves the empty loop formed in a row at the end of the fabric from the rear of the needle drop section to the front side of the needle drop, the sensor detects the passage of the empty loop.
When the passage of the empty ring is detected in this way, the first
The delay operation means outputs a drive signal to the drive means after a predetermined time delay after the empty ring is detected. Therefore, after the sewing machine motor has stopped, the operator simply moves the empty ring and crosses it with the empty ring cutter as described above, and the empty ring is automatically cut leaving a certain length on the sewing machine side. . At this time, since the empty ring is reliably cut by driving the movable blade, there is no possibility that the cut ends will be uneven due to uncut portions of the thread. The length of the loops connected to the fabric remains constant regardless of the level of skill of the worker, and it is possible to prevent the formation of unnecessary loops and the consumption of yarn. Also, when pulling the loop that connects to the rear end of the fabric toward you after stopping the sewing machine, there is a small amount of personal error in the time it takes to guide the loop from the sensor detection part near the needle drop to the loop cutter. Since it is small, there is no possibility of cutting errors in empty rings. Furthermore, when sewing the next piece of fabric is started, as the sewing work progresses, the empty ring elastically held by the empty ring holding means is pulled toward the needle drop section, overcomes the holding elastic force, and is removed from the holding section. break away. Therefore, a part of the empty ring does not remain in a protruding state at the beginning of sewing, or the end of the sewing start of the fabric is not pulled by the empty ring, and the empty ring does not remain in the seam of the fabric. It looks good and settles down.

Hereinafter, an embodiment in which the loop cutting device according to the present invention is applied to a two-needle overlock sewing machine will be described in detail with reference to FIGS. 1 to 11.

Figure 1 shows an external view of a two-needle overlock sewing machine, in which 1 is the sewing machine body, 2 is a throat plate fixed to the sewing machine body 1 via screws 3, 3, and 4 is the front side of this throat plate 2. It is a cross plate provided on the side, and is fixed to the sewing machine main body 1 side via screws 5, 5.

Further, 6 is a fabric guide table for guiding the fabric to be sewn, and 7 is provided on the throat plate 2 so as to be movable up and down, and applies a certain pressing force to the fabric fed on the throat plate 2. This presser foot 7 is attached to the tip of a presser arm 8 which is rotatably supported at the rear of the sewing machine main body 1 and can be raised and lowered so as to be swingable up and down.

Further, P indicates the needle drop portion.

By the way, on the cross plate 4 on this side of the needle drop part P, there is provided a ring holding/cutting device 12 which is an integrated ring cutting device 10 and a ring holding device 11.

The ring cutter 10 has a fixed blade 1 as shown in FIG.
3 and a movable blade 14, the fixed blade 13 is integrally attached to a bracket 15 that fixes it to the sewing machine main body 1 side, and the movable blade 14 is rotatably supported via a screw 16 screwed into the bracket 15. ing.

Further, a locking hole 1 in which a torsion coil spring 17 is wound around the screw 16 and one end thereof is provided in the movable blade 14.
8 and the other end is locked to the lower end of the fixed blade 13, and this torsion coil spring 17 elastically biases the tip of the movable blade 14 downward, and the movable blade 14 is fixed to the fixed blade 13. It is pressed against the side.

On the other hand, in the hollow ring holder 11, a hollow ring pressing member 19 is pivotally supported on a bracket 15 by a pin 20, and a spring 20a is attached to the protruding end of the pin 20 from the bracket.
After the nut 20b is fitted, the nut 20b is screwed. In normal conditions, the hollow ring pressing member 19 is in elastic contact with the bracket 15 and the cross plate 4 or throat plate 2, but its pressing force can be adjusted using the nut 20.
This is done by rotating b. Empty ring cutter 10
The cut ring is pressed between the pressing member 19 and the cross plate 4 or throat plate 2 by the action of the spring 20a.

Further, the movable blade 14 is driven by a rotary solenoid 21 disposed within the sewing machine main body 1.

That is, as shown in FIG. 3, the middle part of the drive lever 22 is fixed to the drive shaft 21a of the rotary solenoid 21, and an engagement pin 23 is provided protruding from one end of the drive lever 22.
3 is an L-shaped slide lever 25 that slides within a slit groove 24 provided on the sewing machine main body 1 side.
The slide lever 25 is engaged with a U-shaped cutout groove 25a provided at one end, and is driven forward and backward by the rotation of the rotary solenoid 21. The tapered surface 26 provided on the upper surface of the slide lever 25 is brought into sliding contact with the lower end of the movable blade 14, so that the movable blade 14 resists the biasing force of the coil spring 17 when the slide lever 25 moves forward. When the slide lever 25 is moved back, the movable blade 14 is rotated downward to cancel the cutting operation.

Reference numerals 27 and 28 are adjustment screws screwed onto the sewing machine main body 1 side, and the tips of these screws 27 and 28 are brought into contact with one side of the drive lever 22 to regulate the amount of rotation of the drive lever 22. I try to do that.

Incidentally, an inner needle plate pawl 29 is provided at the tip of the slide lever 25 and is driven forward and backward along the cloth traveling direction α.

This inner throat plate pawl 29 was conventionally provided integrally with the throat plate at a position parallel to the outer throat plate pawl. It is possible to move backward from the normal forward position parallel to the plate claw (the position shown by the dotted line) in the direction opposite to the direction of movement α of the fabric, and to move forward when actually sewing the fabric and forming an empty ring following this stitching. position and retracted to the retracted position for the rest of the period to prevent the empty ring that is formed just before the start of base stitching from passing over the inner throat plate pawl, which prevents the conventional two-needle overlay. This method allows the sewing of a hollow ring to be performed more smoothly and beautifully than when sewing an empty ring with a lock sewing machine, but since it is not directly related to the gist of the present invention, a detailed explanation will be omitted here. It is something.

Further, in this embodiment, no special driving means for driving the movable blade 14 is provided, but the rotary solenoid 21 for driving the inner throat plate pawl 29 forward and backward is used.

Incidentally, a fabric and empty loop detection sensor 30 is provided above the presser foot 7 via a support fitting 31 that is fixed to the sewing machine main body 1 side. This sensor 30 has a light emitting diode 3 as shown in FIG.
Half mirror 3 that tilts the light emitted from 2 at 45 degrees
3 and a condensing lens 34 onto the throat plate 2, and the light reflected from the throat plate 2 is again transmitted through a condensing lens 34 and a half mirror 33 to a position shifted by 90 degrees from the light emitting diode 32. The projection position of the light emitting diode 32 is a certain distance in front of the needle drop part P and passes through the notched recess 7a provided in the side edge of the presser foot 7 on the needle plate. It is set above 2. Additionally, this sensor 30 has a function of detecting the starting end and ending end of the fabric fed on the throat plate 2, and the function of detecting the starting end and ending end of the fabric fed on the throat plate 2, and the function of detecting the starting end and ending end of the fabric fed on the needle plate 2, and the function of detecting the starting end and end end of the fabric fed on the throat plate 2, and the function of detecting the starting end and end end of the fabric fed on the throat plate 2.As shown in FIGS. 40 and the hollow ring 41 formed continuously at the sewing end of the fabric 40, when the worker brings the light from the light emitting diode 32 projected onto the cutout recess 7a of the presser foot 7 as described above. It also has the function of detecting the passage of the hollow ring 41 by blocking the air ring 41.

Next, the block diagram of the control circuit of this embodiment is shown in Figure 9.
As shown in the figure.

As shown in FIG. 6 of Japanese Patent Laid-Open Publication No. 56-130177, this control circuit is connected to a control circuit indicated by a frame A provided for driving the inner throat plate pawl 29, which provides the necessary control for this device. A circuit is added as shown in frame B.

The control circuit indicated by frame A generates a fabric detection signal outputted from the fabric and empty loop detection sensor 30 and a rotational pulse generator (pulse signal synchronized with the needle movement of the sewing machine, for example, as described in the above-mentioned Publication No. 5). When the timer times set in the sewing start timer 104 and the sewing end timer 105 have elapsed based on the rotation pulses output from
It is designed to drive forward and backward.
Note that a detailed explanation will be omitted here.

By the way, in the control circuit shown in frame part B, 200 is a timer as a first delay operation means for setting the timing for driving the movable blade 14.

In other words, the empty ring detection signal output from the fabric and empty ring detection sensor 30 is input via the comparison circuit 106, and a predetermined time set in the timer 200 has elapsed since the empty ring detection signal was input. A drive signal for exciting the rotary solenoid 21 is output via the OR circuit 201. The timer time set in this timer 200 is as shown in FIG.
The time required for the hollow ring 41 to be conveyed between the fixed blade 13 and the movable blade 14 of the hollow ring cutter 10 as shown in FIG. set in the eye. Further, 202 is a release timer for resetting the output signal of the timer 200.
The timer 200 is reset after a predetermined period of time has elapsed since the input of the output signal.
The timer time set in the release timer 202 is the time required until the movable blade 14 is driven to cut the empty ring 41, and is normally set to about 0.3 seconds.

Further, 203 is a preset counter as a second delay operation means that outputs a stop signal to stop the sewing machine motor (not shown). A counting operation is started at the point in time, and a stop signal is output to the sewing machine motor when the number of rotation pulses outputted from the rotation pulse generator is counted by the preset count amount in this preset counter 203.

Reference numeral 204 is a release timer that outputs a reset signal to the preset counter 203 after a certain period of time from the time when the stop signal output from the preset counter 203 is input.
A stop signal is output to the sewing machine motor only for the timer time set to 04.

Incidentally, the preset amount set in the preset counter 203 can be arbitrarily changed from the outside.

Also, the timing chart of the above control circuit is
Shown in Figure 0.

Next, the operation of this device will be explained with reference to FIGS. 5 to 8 and 10.

When sewing the fabric 40 between the throat plate 2 and the presser foot 7, the preset counter 203 starts counting rotation pulses when the end of the fabric 40 passes through the notched recess 7a provided in the presser foot 7. The sewing machine motor stops when the count number set in the preset counter 203 is reached.

During this time, the fabric 40 completes the base stitching and, as shown in FIG. 5, an empty ring 41 is formed at the sewing end of the fabric 40. By the way, during these periods, the preset counter 203 is used to perform timing control in synchronization with the needle movement of the sewing machine, such as stopping the sewing machine motor when a predetermined number of needle movement pulses set in this counter 203 have been counted. The length of the empty ring 41 formed before the sewing machine motor is stopped is always constant regardless of the sewing speed.

Next, as shown in FIG. 6, when the worker holds the fabric 40 in his hand and rotates the hollow ring 41 counterclockwise, when the hollow ring 41 passes through the notch recess 7a of the presser foot 7, the fabric and the hollow ring are removed. In order to block the light projected from the detection sensor 30, a timer 200 is started, and after a predetermined time set in the timer 200, the rotary solenoid 21 is energized and the movable blade 14 starts the cutting operation.

Therefore, by this time, the empty ring 41 has been placed at the predetermined cutting position of the empty ring cutter 10, that is, between the pressing member 19 of the empty ring holder 111 and the cross plate 4 as shown in FIG. If inserted between the fixed blade 13 and the movable blade 14 of the ring cutter 10, each structure of the empty ring 41 sandwiched between the movable blade 14 and the fixed blade 13 will be cut by the drive of the movable blade 14. The threads are sheared all at once.

Further, as shown in FIG. 8, the cut end of the empty ring 41 that is sheared and left on the sewing machine main body 1 side is pushed toward the throat plate 2 and cross plate 4 by the pressing member 19 provided on the empty ring holder 11. Since the ring 41 held on the upper surface of the throat plate 2 is sewn into the seam one after another when sewing the next fabric starts, the ring 41 held on the upper surface of the throat plate 2 is sewn into the seam one after another as the sewing operation progresses. Therefore, the needle drop P
As a result of being pulled to the side, the hollow ring 41
After overcoming the pressing force of 9, it separates from the empty ring holder 11 and is completely sewn into the seam of the fabric.

Therefore, according to the empty ring sewing device in the overlock sewing machine according to the present invention, first, the empty ring 4 is
1 is sheared all at once by a ring cutter 10 having a movable blade 14 on at least one side,
Each thread that makes up the hollow ring is cut at the same time, and the shape of the hollow ring is maintained even at the cut end, so it is beautiful even when sewn into a seam, and does not protrude from the seam. There is no risk of the sewing machine coming out from the sewing start end.

Further, the movable blade 14 is driven by a drive means such as a rotary solenoid 21, and the needle drop portion P
When moving the empty ring 41 to the front side together with the fabric 40, the passage of the empty ring 41 is detected by the fabric and an empty ring detection means such as the empty ring detection sensor 30, and the empty ring 41 is moved to the front side together with the fabric 40. Timer 2 starts from the moment of detection.
Since the drive means is energized to cut the empty ring 41 after a predetermined time set in the delay operation means such as 00, the operator has to move the empty ring 41 to a predetermined cutting position. Only empty ring 4 is sufficient.
Cutting No. 1 is automatically performed.

In addition, since the cut ring 41 is held under pressure by adjusting the pressing force to an appropriate level by the pressing member, the ring can be released at an appropriate timing while being sewn into the seam. In conventional clamping methods using electromagnetic solenoids, etc., an error may occur in the timing of releasing the empty ring, resulting in a portion of the empty ring remaining protruding from the sewing start end, or when the fabric is sewn. This also eliminates the possibility that the starting side may be pulled through the clamped empty ring.

In addition, a preset counter 203 is provided, and the sewing machine motor is stopped when a certain number of needle movement pulses are counted from the time when the fabric and empty ring detection sensor 30 detects the end of the fabric.
Since the length of the hollow ring 41 formed continuously on the fabric 40 after sewing is completed can always be constant regardless of the sewing speed, the length of the hollow ring 41 remaining on the fabric 40 side after cutting the hollow ring is also the shortest length. The aligning threads are not wasted, and the work of moving the fabric 40 toward the front side becomes reliable and easy.

Furthermore, in this embodiment, no special driving means for the movable blade 14 is provided, and the movable blade 14 is driven by the rotary solenoid 21 that drives the inner throat plate pawl 29 forward and backward. The configuration is simple and can be implemented at low cost.

In this embodiment, a two-needle overlock sewing machine has been described, but it can also be applied to a single-needle overlock sewing machine. It is necessary to provide special drive means for driving the blade 14. Further, in this embodiment, a rotary solenoid 2 is used as a driving means for driving the movable blade 14.
1, for example, as shown in FIG. 11, a pneumatic cylinder 50 may be used, and the pneumatic pressure of the pneumatic cylinder 50 may be controlled by a solenoid valve (not shown) or the like. That is, the operating shaft 50a of the pneumatic cylinder 50 is fitted into one end of the connecting link 51, and the connecting link 52 is further fixed integrally to the other end of this connecting link 51 via screws 53, 53. An engagement pin 54 protruding from one end of the connecting link 52 is engaged with a U-shaped notch 25a provided at one end of the slide lever 25, and the slide lever 25 is moved by pneumatic control of the pneumatic cylinder 50. It is designed to move forward and backward.
Incidentally, the same parts as those shown in FIG. 2 are given the same numbers, and the explanation will be omitted.

[Brief explanation of the drawing]

Fig. 1 is a general view of an overlock sewing machine showing one embodiment of the present invention, Fig. 2 is a perspective view showing an empty ring cutter and an air ring holding means in the same embodiment, and Fig. 3 is a movable ring sewing machine in the same embodiment. A side view showing the blade driving means, FIG. 4 is a schematic diagram of the fabric and empty ring detection sensor in the same embodiment, FIGS. 5 to 8 are explanatory diagrams of the operation of the same embodiment, and FIG. 9 is a diagram of the same embodiment. 10 is a timing chart in the same embodiment, and FIG. 11 is a perspective view showing another embodiment of the movable blade driving means. 10... Empty ring cutter, 11... Empty ring holding means,
13... Fixed blade, 14... Movable blade, 21... Drive means (rotary solenoid), 30... Fabric and empty ring detection means, 50... Drive means (pneumatic cylinder), 200... First delay Operating means, 203...
...Second delay operation means.

Claims (1)

[Scope of Claims] 1. An empty loop connected to the sewing end of the fabric is pulled along with the fabric and cut by an empty ring cutter before the needle drop, and the empty ring on the side connected to the needle is cut before the needle drop. An empty ring sewing device for an overlock sewing machine, in which the held empty ring is held by an empty ring holding means and sewn into the sewing start end of a fabric to be newly sewn, the movable blade of the empty ring cutter a driving means for driving the hollow ring; the hollow ring holding means for elastically pressing and holding the hollow ring cut by the hollow ring cutter; a sensor for detecting an object passing near the needle drop; a sewing machine; a rotary pulse generator that generates a needle movement pulse synchronized with the needle movement of the sewing machine; and a second pulse generator that outputs a stop signal to the sewing machine motor when the sensor has counted a predetermined number of the needle movement pulses from the time when the sensor detects the end of the fabric. a delay operation means; a first circuit that outputs a drive signal to the drive means after a predetermined time delay from the time when the sensor detects an empty ring;
An empty ring sewing device for an overlock sewing machine, comprising: a delay operation means; and an empty ring sewing device.