JPH0634871B2 - Overlock sewing machine empty chain stitching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention provides an empty ring formed in series with an overlock sewing machine to form a seam on an edge of a cloth by over stitching, and then forming the seam on the seam. The present invention relates to an empty ring stitching device provided for the overlock sewing machine in order to cut a predetermined length from the sewing machine side and sew an empty ring continuing from the sewing machine side into a seam of the next cloth. .

[Conventional technology]

A conventional empty-loop stitching device attached to an overlock sewing machine is provided with an empty-loop holding and cutting device in which a cutting blade and a holding member made of an elastic material are integrated on a work surface on the front side of a needle drop portion. In addition, the operator brings the empty ring created when the sewing is completed together with the cloth to the front side and presses it against the cutting blade, cuts at the cutting edge, and the free end of the cut empty ring is held by the holding member. Hold the empty ring left on the sewing machine side on the upper surface of the needle plate, and sew this empty ring into the stitch of the next cloth to make a special bartacking work for the frayed stitch at the sewing start part. It was intended to be able to prevent without doing.

However, in such an empty-loop sewing-in device, in order to cut the empty ring formed in a continuous manner with the cloth, the operator moves the cloth to the front side of the needle drop point every time the sewing of one cloth is completed. This has been a problem in improving work efficiency and automating work.

For this reason, recently, as disclosed in JP-A-53-128443 and the like, an empty ring connected to a seam formed on a fabric is sucked into a suction tube at a rear side of a needle drop portion, and an opening of the suction tube is opened. The empty ring was cut from the sewing machine side with a predetermined length left by a cutting device provided inside, and the free end of the empty ring connected from this sewing machine side was moved to the front side of the needle drop portion by wind pressure, and thus moved. After sucking the free end of the empty ring by the free end suction part of the empty ring, the empty ring holding part arranged on the work surface of the cross plate is operated to hold the free end of the empty ring. Has been done.

[Problems to be solved by the invention]

However, in the conventional apparatus such as the one disclosed in Japanese Patent Laid-Open No. 53-128443, the empty ring holding section and the free end suction section of the empty ring are arranged on the work surface. The gripping part or the like interferes with the cloth feeding, and the cloth cannot be fed straight, so that the sewing looks unsatisfactory, and in extreme cases, the cloth may be damaged.

Further, in the conventional device, the length of the hollow ring sewn into the seam of the fabric is determined by the cutting position of the cutting device provided in the opening of the suction tube, so it is desired to change the length of the hollow ring sewn depending on the product. In this case, it was difficult to deal with this.

The present invention has been made in view of the above circumstances, and it is a first object of the present invention to provide an empty-loop sewing-in device for an overlock sewing machine that does not cause any trouble in insertion and feeding of cloth. The purpose is.

A second object of the present invention is to provide a pneumatic loop stitching device for an overlock sewing machine capable of changing the length of the pneumatic loop stitched to the seam of the fabric.

[Means for solving problems]

In order to achieve the first object, the present invention is provided on the front side of the needle drop portion, and the upper surface is flush with the working surface of the sewing machine, and the free end of the air ring moved by wind pressure is A holding plate that is movable in a direction intersecting the sewing shaft to form an insertable insertion port on the work surface, and is provided above the insertion port toward the insertion port side formed by the movement of the holding plate. The air blowout port is provided, and the free end of the hollow ring is inserted into the insertion port by the air blown from the air blowout port, and then the clamping plate is moved to close the insertion port to close the hollow ring with the needle. In order to achieve the above-mentioned second object, an empty chain stitching device for an overlock sewing machine, which is characterized in that it can be pinched on the front side of the drop portion, is provided on the front side of the needle drop portion, and the upper surface But An insertion port, which is on the same plane as the working surface of the sewing machine and is cut by the first cutting device behind the needle drop portion, and into which the free end of the empty ring moved by wind pressure can be inserted, is on the working surface. A first holding plate movable in a direction intersecting with the sewing shaft to be formed, and movable in a direction intersecting the sewing shaft together with the first holding plate in a state of being in close contact with the first holding plate only when it is driven. Further, when only the first holding plate moves, a second holding plate that forms the insertion opening between the first holding plate and the first holding plate, and work toward the insertion opening side formed by the movement of the first holding plate An air blowout port provided above the surface and a second cutting device provided between the needle drop portion and the first holding plate. Front end After inserting into the insertion opening, the first holding plate is moved to close the insertion opening to hold the empty ring on the front side of the needle drop portion, and in the empty ring holding state, the first holding plate and the second holding plate are held. By moving together, the sky ring can be moved to the second position.
The gist of the empty ring sewing device of an overlock sewing machine is characterized in that the empty ring is moved to the blade edge portion of the cutting device to cut the empty ring between the needle drop portion and the sandwiching portion.

[Action]

According to the empty-loop sewing-in device of the overlock sewing machine according to the first aspect of the present invention, the free end of the empty ring moved by the wind pressure is formed by moving the holding plate. It is inserted by the air blown from the air blowing port, and then the holding plate moves to close the insertion port, so that it is held on the front side of the needle drop portion. Moreover, the upper surface of the holding plate is flush with the work surface, so that the holding plate does not obstruct the insertion of the next cloth from the front side.

The empty-loop sewing-in device for an overlock sewing machine according to the second aspect of the present invention is the same as the holding plate in the empty-loop sewing-in device according to the first aspect of the present invention by replacing the holding plate with the first holding plate. By the action of the above, the empty ring is held between the first holding plate and the second holding plate, and further, the first holding plate and the second holding plate are moved together in the state of holding the empty ring, whereby the empty ring is moved. Is moved to the cutting edge portion of the second cutting device, and the empty ring is cut by the second cutting device between the needle drop portion and the holding portion.

〔Example〕

 Hereinafter, the present invention will be described based on illustrated embodiments.

1 to 3F, 1 is a cross plate of an overlock sewing machine, and a work plate 1a of the cross plate 1 has a needle plate 2 fitted therein at a position corresponding to a sewing machine needle. The needle plate 2 is fixed to the cross plate 1 by bolts 3, and the upper surface thereof constitutes a part of the working surface 1a. In addition, the needle plate 2 is formed with a needle drop portion 4 that penetrates the work surface 1a in the vertical direction, and a portion adjacent to the needle drop portion 4 is used as a starting point to move backward (direction of arrow B in the figure). The extending tongue 5 is integrally attached.
2A to 2C, X indicated by a one-dot chain line is a sewing shaft of this overlock sewing machine which coincides with the cloth feeding direction passing through the needle drop portion 4.

On the working surface 1a on the side where the tongue 5 is attached to the sewing shaft X and in front of the needle drop portion 4 (in the direction of the arrow A in the drawing), one side on the sewing shaft X and a sewing machine orthogonal to the sewing shaft X are formed. The rear side is formed by the needle plate 2, the front side of the sewing machine that is orthogonal to the sewing axis X is formed by the cross plate 1, and the recess 6 in which the side parallel to the sewing axis is the open side is formed. It is set up. A holding plate 7 whose upper surface is flush with the work surface 1a is fitted in the recess 6 so as to be movable in a direction orthogonal to the sewing axis X.

The holding plate 7 includes a first holding plate 71 arranged on the open side of the recess 6 and a second holding plate 72 arranged on the bottom side of the recess 6, and the first holding plate 71 The second holding plates 72 can be in close contact with each other at least on the needle drop portion 4 side. Further, the mechanism to be described later allows the first holding plate 71 to move independently in the direction orthogonal to the sewing axis X, whereby the second holding plate 71 is moved.
As shown in the figure, an empty ring insertion port H can be opened between the second holding plate 72 and the second holding plate 72. Meanwhile, the second holding plate
When 72 moves in a direction orthogonal to the sewing axis X, the first holding plate 71 also moves together.

Reference numeral 8a denotes a presser foot for holding a cloth as a work piece between the needle plate 2 and the presser foot 8a.
It is attached to the tip of a presser base 8b that is swingably supported on the presser foot.This presser base 8b swings by operating an air pump 8c, and the presser foot 8a is moved between the cloth presser position and the presser release position. Up and down.

Further, behind the tongue metal 5, a cloth guide 9 is provided upright from the work surface 1a at a predetermined distance from the sewing axis X and parallel to the sewing axis X.

An air ring cutting section 10 is provided on the back side of the guide surface of the cloth guide 9. The empty ring cutting section 10 is connected to an air suction source (not shown) and is provided with a suction passage 11 having a back surface of the cloth guide 9 as a part of an inner wall, and the suction hole 11a of the suction passage 11 is provided with a needle. The cloth guide 9 is provided near the rear end of the plate 2.
The first cutting device 12 is provided in the suction hole 11a. The first cutting device 12 has a fixed blade 12a having a cutting edge fixed to the lower end of the suction hole 11a, and is rotatably supported on the outside of the suction passage 11 from the upper surface of the suction passage 11 into the suction passage 11. The movable blade 12b is inserted, and the movable blade 12b is driven by a member interlocked with the main shaft of the sewing machine so that the blade edge thereof intersects with the fixed blade 12a. By doing this,
The empty ring generated by driving the sewing machine is the suction port 11a.
It is further inhaled and is cut by the fixed blade 12a and the movable blade 12b so that an empty ring of a constant length always remains on the needle plate side. still,
The drive of the movable blade 12b does not necessarily need to be linked to the drive of the sewing machine. For example, when the number of movements of the needle after the end of the cloth has passed the needle drop portion 4 is counted and the number of movements of the needle reaches a set number, After stopping the sewing machine with, the machine may be driven with a solenoid or the like, or
After confirming that the required length of the empty ring has been created, it may be driven by pedal operation or the like.

An air pressure feed pipe 13 connected to an air supply source (not shown in FIGS. 1 to 3F) in parallel with the suction passage 11 is disposed on the back surface side of the cloth guide 9. This air pressure pipe
At the tip of 13 is provided a nozzle 13a, whose open end is connected to the cloth guide 9 on the front side of the suction hole 11a and blows air in a direction orthogonal to the sewing axis X.

On the working surface 1a between the sewing shaft X adjacent to the suction hole 11a of the suction passage 11 and the cloth guide 9, an air suction source for air suction (not shown in FIGS. 1 to 3F) is connected. The suction port 14a of the suction tube 14 which is arranged to pass through the inside of the cross plate 1 is opened. That is, the suction port 14a is arranged on an extension line parallel to the sewing axis X extending from the tip of the tongue 5.

A blow pipe 15, which is connected to an air supply source (not shown in FIGS. 1 to 3F) and has a nozzle 15a as an air outlet at the tip, is supported on the pressing base 8b. The nozzle 15a is supported so as to blow air to the insertion port H side formed by driving the first holding plate 71 when the presser base 8b raises the presser foot 8a to the presser release position. .

Next, the drive mechanism of the holding plate 7 will be described.

First, the first holding plate 71 will be described. The first holding plate 71 is the first holding plate 71 provided in the cross plate 1.
It is driven by operating the air cylinder 16. Explaining this in detail below, a mounting piece 71a is integrally formed on the lower surface of the first holding plate 71, and the mounting piece 71a is
One end of a rod 18 slidably supported by the bracket 17 is fixed by penetrating the bracket 17 attached to the sewing machine main body in a direction orthogonal to the sewing axis X. This rod 18
A male screw 18a is screwed on the protruding portion from the bracket 17, and a spring receiver 19 is screwed on the male screw 18a. A compression spring 20 is stretched between the spring receiver 18 and the bracket 17, and the first holding plate 71 attached to the rod 18 by the urging force of the compression spring 20 is replaced with the second holding plate 72. It is urged in the direction of close contact (direction of arrow C in the figure). Piston rod of the first air cylinder 16
Attached to the rod 16a is a rod pressing member 21 that comes into contact with or comes close to the tip of the rod 18 when the first holding plate 71 is in close contact with the second holding plate 72 when the piston rod 16a is retracted. Has been done. Incidentally, a male screw is screwed on the piston rod 16a, and by adjusting the detent nut 22 screwed to this male screw,
The position of the rod pressing member 21 is set to the piston rod 16a.
It can be adjusted in the forward and backward directions. The first air cylinder 16 is attached to a position where the rod pressing member 21 can press the rod 18 against the urging force of the compression spring 20 by extending the piston rod 16a.

Next, driving of the second holding plate 72 will be described. The second holding plate 12 is driven by a second air cylinder 23 provided in the lower part of the cross plate 1 as a drive source. In detail, first, the second holding plate 72 is integrally formed with an operation piece 72a extending below the work surface 1a on the front side (arrow A side in the drawing). When the second holding plate 72 comes into contact with the needle plate 2 on the sewing axis X, the operation piece 72a is simultaneously formed with the contact member 24 integrally formed on the bracket 17.
Abut. One end of a guide rod 25 extending through the operation piece 72a and extending in a direction orthogonal to the sewing axis X is attached to the contact member 24, and the other end of the guide rod 25 is attached to the cross plate 1. It is connected to a fixed spring holder 26. Then, the spring receiving recess 26a formed in the spring receiving base 26 is formed.
The compression spring 27 is stretched in the spring receiving recess 72aa formed in the operation piece 72a, and the operation piece 72a is biased toward the contact member 24 by the biasing force of the compression spring 27. On the other hand, the abutment member 24 and the bracket 17 integral with the abutment member 24 are formed with a cutout portion 28 that opens to a contact surface with the operation piece 72a, and the second air cylinder 23 is formed in the cutout portion 28.
The tip of the swing arm 29 for transmitting the operation of is inserted. The swing arm 29 is formed in an L shape, and its corner portion 29a is rotatably supported. The upper end portion of one side rising from the corner portion 29a is inserted into the cutout portion 28 as described above. ing. Also, this swing arm
At the tip of one side extending laterally from the corner portion 29a of 29,
A rod receiver 29b is formed so as to come into contact with the piston rod 23a which moves forward and backward in the second air cylinder 23.
Therefore, when the piston rod 23a extends and pushes the rod receiver 29b upward, the swing arm 29 swings around the corner portion 29a, and the tip end portion inserted into the cutout portion 28 has the contact member 24. The operation piece 72a is pressed against the spring support 26 side against the biasing force of the compression spring 27 by protruding from the contact surface between the operation piece 72a and the operation piece 72a. When the operation piece 72a is pressed in this way, the second holding plate 72 formed integrally with the operation piece 72a moves to the first holding plate 71 side together with the first holding plate 71. . At this time, it goes without saying that the first holding plate 71 moves against the biasing force of the compression spring 20. Further, when the piston rod 23a of the second air cylinder 23 is retracted, the tip end of the swing arm 29 is cut out.
Since it returns to the inside, the operation piece 72a is biased by the compression spring 27 and contacts the contact member 24, and at the same time, the second holding plate 72 contacts the needle plate 2 on the sewing shaft X. Further, when the second holding plate 72 is moved so as to come into contact with the needle plate 2 on the sewing shaft X in this manner, the first holding plate 71 is also joined to the second holding plate 72 by the urging force of the compression spring 20. Move to the sewing axis X side. Therefore, when the second air cylinder 23 is actuated, the first holding plate 71 and the second holding plate 72 move together while being in close contact with each other.

A second cutting device 30 including a fixed blade 30a and a movable blade 30b each having a cutting edge parallel to the sewing axis X is disposed between the tongue 5 and the holding plate 7. This second cutting device
30 has the function of trimming the fabric edges prior to overedging,
As will be described below, the action of cutting the empty ring is performed, and as shown in FIG. 2C, the first holding plate 71 and the second holding plate 71
The holding plate 72 is provided on the movement locus of the empty ring Ch sandwiched between the holding plates 72 when the holding plates 72 move together to the first holding plate 71 side. Further, the movable blade 30b intersects each cutting edge by reciprocating around the rear side of the fixed blade 30a in synchronism with the driving of the sewing machine, whereby the empty ring Ch is moved as shown in FIG. 2C. It is designed to be cut when crossing a cutting device.

Incidentally, 31 is a cloth edge detecting sensor for detecting the edge of the cloth.

Next, the operation of the pneumatic chain stitching device configured as described above will be described with reference to the pneumatic circuit diagram shown in FIG. 4 and the schematic diagrams for explaining the operating process shown in FIGS. 3A to 3F.

First, the air ring cutting section 10 is operated to separate the air ring connected to the cloth from the cloth. That is, as will be described later, when the sewing machine is driven, the air suction source 101 (shown only in FIG. 4) connected to the suction passage 11 is activated, so that the empty loop formed in series with the seam of the cloth is By feeding, it is automatically sucked into the suction hole 11a and is driven by the movable blade 12b to be separated from the cloth. FIG. 3A shows a state in which the empty ring Ch separated from the cloth is sucked into the suction hole 11a. The space ring Ch has its base end side wound around the tongue 5.

The following operation will be described with reference to the timing chart shown in FIG.

When the driving of the sewing machine is stopped in the state shown in FIG. 3A, the suction by the air suction source 101 is also stopped. Here, when the plunger 201a is pressed to switch the pilot air supply switching valve 201 by performing a stepping operation of a step plate (not shown) of the sewing machine, the pilot air is supplied from the pilot air supply source 102 to the supply passage 301. Is supplied. The pilot air sent out to the air supply path 301 is used as the switching valve 2 that constitutes the delay timer valve device 202 for setting the idle suction time.
It is sent to the pressure receiving portion of the pneumatic switching valve 203 via 02c and the air supply path 302. As a result, this pneumatic switching valve 20
3 is an air suction source 103 for suction of the air ring and the suction tube described above.
14 and the suction port 14a is connected to the free end of the empty ring Ch that is cut by the empty ring cutting unit 10 to the 3B side.
Aspirate as shown. At this time, the base end side of the empty ring Ch is pulled out from the tongue 5 and the entire empty ring Ch is stretched.

Since the air sent to the air supply path 301 is also sent to the pressure receiving portion of the pneumatic switching valve 205 via the shuttle valve 204, the pneumatic switching valve 205 is connected to the pump operating air supply source 105 and The air pump 8c is switched to the connected side, and the air pump 8c
Raise.

When the plunger 201a of the pilot air supply switching valve 201 is pressed in this manner, as is clear from FIG. 5,
The suction from the suction port 14a and the lifting of the presser foot 8c are started at the same time.

The delay timer valve device 202 is configured by connecting a flow rate adjusting valve 202a, an air tank 202b, and the switching valve 202c in series. The air tank 202b is designed to discharge air so as to be sent to the pressure receiving portion of the switching valve 202c when the amount of air inside reaches a predetermined amount. Therefore, if the flow rate adjusting valve 202a is used to adjust the amount of air sent to the air tank 202c per hour and set the time for the amount of air in the air tank 202b to reach a predetermined amount, the air is supplied to the air supply passage 301. The switching valve 202c is switched after a predetermined time, and the supply of pilot air to the air supply passage 302 is stopped. Then, when the supply of pilot air to the air supply path 302 is stopped, the pneumatic switching valve 203 switches to the side that disconnects the connection between the suction tube 14 and the air suction source 103 for air suction. Suction from 14a is stopped. That is, the suction time T ₁ of the suction port 14a shown in FIG. 5 is determined by adjusting the flow rate adjusting valve 202a. As shown in FIG. 5, the pilot air supply switching valve before the suction time T ₁ elapses.
When the pressing of the plunger 201a by 201 is released, the presser base 8b is lowered at that time and the suction from the suction port 14a is stopped.

Reference numeral 206 denotes an area difference double Paulott valve. Among the pressure receiving portions of the area difference double pilot valve 206, the air supply passage 302 is connected to a first pressure receiving portion 206a having a large cylinder diameter, and a second cylinder portion having a small cylinder diameter. An air supply path for the pressure receiving portion 206b
301 is connected. The area difference double pilot valve 206 disconnects the air supply passage 301 and the air supply passage 303 connected to the flow rate adjusting valve 207a described later. That is, when the pilot air supplied to the air supply path 301 is being sent to the air supply path 302 via the switching valve 202c, the area difference double paolotte valve 206 is provided with the air supply path 301 and the air supply path 303. Located on the side that disconnects the
When 202c is switched and pilot air is no longer sent to the air supply passage 302, pilot air is supplied only to the second pressure receiving portion 206b, so that the air supply passage 301 and the air supply passage 303 are connected to each other. . Therefore, the area difference double pilot valve 206 supplies the pilot air to the air supply passage 303 at the time point t ₁ (see FIG. 5) when the suction of the suction port 14a is stopped.

The delay timer valve device 207 for setting the holding start time has the same configuration as the delay timer valve device 202 described above. By adjusting the flow rate adjusting valve 207a, the air tank 20
The time during which the air is sent to the pressure receiving portion of the switching valve 207c by the 7b can be set. Therefore, the switching valve 207c is switched after a lapse of a predetermined time T ₂ after the pilot air is supplied to the air supply passage 303, and the holding operation pilot air supply source 107 is connected to the air supply passage 304.

The air supply path 304 includes flow rate adjusting valves 208a, 209a of a delay timer valve device 208 for setting air pressure feeding time for air circulation movement, a delay timer valve device 209 for setting insertion opening time, and a delay timer valve device 210 for setting blow time. , 210a and switching valve 208
It is connected to the c, 209c, and 210c ports. The delay timer valve devices 208, 209 and 210 are respectively flow rate adjusting valves 208a and 209.
a, 210a, air tanks 208b, 209b, 210b, switching valves 208c, 209c,
210c is connected in series, and flow control valves 208a, 209a, 210a
Is adjusted to set the time from the supply of air to the air supply passage 303 to the discharge of air from the air tanks 208b, 209b, 210b. Switching valves 208c, 209c, 21
0c indicates that the air supply passages 304, 305, 306, 3 are respectively set until the air is discharged from the air tanks 208b, 209b, 210b.
It is located on the side connected to 07, and air tanks 208b, 209b,
When air is discharged from 210b, the air supply path
The connection between 304 and the air supply passages 305, 306, 307 is switched to the disconnecting side.
These air supply paths 305, 306, 307 are connected to the pressure receiving portions of the pneumatic switching valves 211, 212, 213, respectively. And
The air pressure switching valve 211 is switched to the side connecting the drive air supply source 108 to the above-described air pressure feeding pipe 13 when air is supplied to the air supply passage 305, and the pneumatic switching valve 212 is used.
By supplying air to the air supply passage 305,
The driving air supply source 109 is switched to the side connected to the first air cylinder 16, and the pneumatic switching valve 213 operates the driving air supply source 110 by supplying air to the air supply passage 307. Switching to the side connected to the blow pipe 15.

By supplying air from the driving air supply sources 108, 109, 110 in this way, air is blown out from the nozzle 13a of the air pressure feeding pipe 13, the first air cylinder 16 is operated, the piston rod 16a is extended, and the blow pipe 15 Air also blows out from the nozzle 15a. Therefore, the nozzles 13a, 1
The blowout of air from 5a and the extension of piston rod 16a are started simultaneously at time t _{2 as} shown in FIG. 5, and as is apparent from the above description, the time T ₃ during which air is blown out from nozzle 13a. The time T ₄ during which the piston rod 16a is driven toward the extending side and the time T ₅ during which air is blown out from the nozzle 15a are set by adjusting the flow rate adjusting valves 208a, 209a, 210a. As shown in FIG. 5, these times T ₃ , T ₄ , T ₅ are set to T ₃ <T ₄ <T ₅ .

When the air is blown out from the nozzle 13a, as shown in FIG. 3C, the empty ring Ch rotates around the tip of the tongue 5, and the free end Co of this empty ring Ch is moved to the front side of the sewing machine. . As described above, while the free end Co of the empty ring Ch moves, the piston rod 16a of the first air cylinder 16 extends and the first holding plate 71 moves, so that the second side B is located on the front side of the sewing machine. As shown in the drawings and FIG. 3D, an empty ring insertion port H is formed, and the empty ring Ch is blown into this insertion port H by the air blown from the nozzle 15a. As described above, the reason why the air blowing time T ₅ from the nozzle 15a is made longer than the driving time T ₄ of the first air cylinder 16 is that the driving air supply source 109 and the first air cylinder 16 are connected. This is because it takes time from when the piston is cut off until the piston rod 16a retracts and the insertion port H is closed. During this time, air is blown from the nozzle 15a as shown in FIG. 3E. The empty ring Ch is held between the first holding plate 71 and the second holding plate 72 without slack.

As described above, when the pilot air supply switching valve 201 is released from being pressed against the plunger 201a by the stepping operation of the step plate after the empty ring Ch is held as shown in FIG. 3E, the shuttle valve 204 is inserted. Pneumatic switching valve 2
The air sent to the pressure receiving part of 05 is shut off, and the pneumatic switching valve 205 returns to the side that disconnects the connection between the pump operating air supply source 105 and the air pump 8c, so that the presser foot 8c becomes a cloth on the needle plate 2. Lower to the work clamp position. Further, the switching valve 202c returns to the initial state by releasing the pressing force to the plunger 201a, and the switching valve 207c also returns to the initial state to disconnect the holding operation pilot air supply source 107 and the air supply passage 304. . Then, the supply of air to the air supply passage 304 is cut off, so that the switching valves 208c, 209c, 210c also return to the initial state.

Next, by operating the foot plate for raising the presser foot of the sewing machine, the plunger 2 of the pilot air supply switching valve 214 is operated.
14a is pressed to pilot air supply source 111 and air supply passage 30
Connect 1 '. The air supplied to the air supply path 301 ′ is supplied to the pneumatic switching valve 205 via the shuttle valve 204.
Of the pneumatic switching valve 205
Switches again to the side connecting the pump operating air supply source 105 and the air pump 8c, and the presser foot 8a rises to the presser release position. And after inserting the fabric in this position,
When the pressure on the operation portion 214a is released, the connection between the pilot air supply source 111 and the air supply path 301 'is cut off, the pneumatic switching valve 205 returns to the initial state, and the air of the air pump 8c is evacuated and the presser foot is pressed. 8a descends and sandwiches the cloth with the needle plate 2.

In this way, after the cloth is sandwiched between the presser foot 8a and the needle plate 2, the sewing machine is driven to form a seam at the edge of the cloth. A pilot air supply switching valve 215 is provided so that the plunger 215a is pressed when the footboard is pushed forward to drive the sewing machine.When the plunger 215a is pressed, the pilot air supply source 112 and the air supply are supplied. Switch to the side that connects path 308. The air supply passage 308 is connected to the pressure receiving portion of the pneumatic switching valve 216 and one inlet of the shuttle valve 217.

The pneumatic switching valve 216 switches to the side connecting the air supply source 101 and the suction passage 11 when air is sent to the switching operation unit. Thus, the air supply source 101 and the suction passage 11 are connected at the same time when the sewing machine is driven, and the air is sucked from the suction hole 11a. Therefore, the empty ring formed to reach the suction hole 11a from the tongue 5 connected to the rear end of the fabric is always sucked into the suction hole 11a, and the first cutting device 12 described above with reference to FIG. 3A. You will be cut as you did.

On the other hand, the air sent from the air supply passage 308 to the shuttle valve 217 is sent to the pressure receiving portion of the pneumatic switching valve 218 via the shuttle valve 217, and the pneumatic switching valve 218 is supplied to the pilot air supply source 113 and the air supply. Switch to the side that connects path 309.

The air supply path 309 is connected to the ports of the flow rate adjusting valve 219a and the switching valve 219c of the delay timer valve device 219 for setting the disconnection start time, and also to the port of the pneumatic switching valve 221.

In the pressure receiving portion of the pneumatic switching valve 221, the air supply passage 3
When 07 is connected and air is not sent to the air supply passage 307, that is, at all times, the pneumatic switching valve 221 connects the air supply passage 309 to the other inlet of the shuttle valve 217. Connected to the air passage 310. Therefore, once the pneumatic switching valve 218 is switched to connect the pilot air supply source 113 and the air supply path 309, for example, the driving of the sewing machine is stopped and the pressure receiving portion of the pneumatic switching valve 218 from the air supply path 308 is stopped. Even if the air is no longer sent to the air supply source, the air sent out from the air supply source 113 is sent to the pressure receiving portion of the air pressure type switching valve 218 via the air pressure type switching valve 221, the shuttle valve 217, etc. Unless the air supply passage 309 and the air passage 310 are disconnected by switching 221, air is continuously sent from the pilot air supply source 113 to the air supply passage 309.

When the air is sent to the air supply passage 309 as described above, the delay timer valve device 219 adjusts the flow rate adjusting valve 219a to set the time for the air tank 219b to release the air, and thereby the air supply passage 309 is supplied. The switching valve 219c is switched to the side connecting the air supply passage 309 and the air supply passage 311 after a predetermined time T ₆ from the air is sent. The air supply passage 311 is connected to the air supply passage 312 connected to the pressure receiving portion of the pneumatic switching valve 222 via the constant switching valve 220c that is not receiving pressure in the pressure receiving portion. The switching valve 220c constitutes a part of the delay timer valve device 220 for setting the cutting end time, and the delay timer valve device 220 includes the flow control valve 2c.
20a, an air tank 220b, and the switching valve 220c, and the air supply passage 311 is connected to the flow rate adjusting valve 220a.
Therefore, by adjusting the flow control valve 220a, the switching valve 220c is pressed by the air air to the air supply passage 311 is discharged from the air tank 220b from being supplied after a predetermined time T _7, the air supply passage 311 And the air supply path 312 is disconnected.

The pneumatic switching valve 222 is operated when air is being sent to the air supply passage 312, that is, when the switching valve 219c is the air tank 21.
After switching by the air discharged from 9b, switch valve 22
During the predetermined time T ₇ until 0c is switched by the air discharged from the air tank 220b, the driving air supply source 114 and the second air cylinder 23 are switched to each other. Accordingly, during the predetermined time T ₇ , the piston rod 23a of the second air cylinder 23 pushes the rod receiver 29b of the swing arm 29 upward, and the swing causes the swing arm 29 to swing around the corner portion 29a. Move. Due to this swinging, the upper end of the swinging arm 29 is an operation piece integrally formed with the second holding plate 72.
72a resists the urging force of the compression spring 27 stretched between the operation piece 72a and the spring receiving base 26, and the compression spring 20 urging the first holding plate 71 toward the second holding plate side. The first holding plate 71 and the second holding plate 72.
As shown in FIGS. 2C and 3F, moves the empty ring Ch to the side closer to the second cutter 30 while holding the empty ring Ch. By this movement, when the empty ring Ch intersects the second cutter 30 and is inserted between the fixed blade 30a and the movable blade 30b, the movable blade 30b is driven in synchronization with the driving of the sewing machine. As a result, the empty ring Ch sewn into the seam at the front end of the fabric is separated from the holding portion by the first holding plate 71 and the second holding plate 72.

As is clear from the above description of the operation, the length of the hollow ring sewn into the cloth is determined by the first holding plate 71 and the second holding plate.
It can be changed depending on the timing of moving 72 together. In other words, conversely, the flow control valve 219a of the delay timer valve device 219 is adjusted to drive the sewing machine until the second air cylinder 23 operates for a predetermined time T ₆
By changing, it is possible to select the length of the hollow ring sewn into the fabric.

As described above, air is continuously sent from the pilot air supply source 113 to the air supply passage 309 unless the pneumatic switching valve 221 is switched to disconnect the connection between the air supply passage 309 and the air passage 310. The pneumatic switching valve 221 is
Plunger 2 of the pilot air supply switching valve 201 described above
By a series of operations started by pressing 01a, switching is performed only when air is sent to the air supply passage 307 to connect the blow pipe 15 and the driving air supply source 110. Therefore, in a state where the air is not sent to the air supply path 307, the second air cylinder 23 is not driven even if the driving of the sewing machine is stopped and then the sewing machine is driven again. In this way, between the air supply passages 308 and 309,
By providing a circuit constituted by the shuttle valve 217, the pneumatic switching valve 218, the pilot air supply source 113, the pneumatic switching valve 221 and the air passage 310, even if the driving of the sewing machine is once stopped at the corner portion of the cloth or the like. After that, the second holding plate 72 will not operate unnecessarily.

As described above, the empty ring formed by connecting the seam to the end of the previous fabric is separated by the first cutting device 12, moved to the front side of the needle drop part 4 and held, and the tip of the next fabric is cut off. When sewn into, the fabric can be cut from the fabric by the second cutter 12 and sewn into the seam formed in the next fabric by a predetermined length.

In performing the function of the pneumatic chain stitching device for the overlock sewing machine according to the present invention, as shown in FIG. 6, the area difference double pilot valve 206 is removed from the pneumatic circuit shown in FIG. An air supply passage 301 connected to the switching valve 201 instead of the air supply passage 301 in FIG.
a is directly connected to the flow rate adjustment valve 207a of the holding timer setting delay timer valve device 207, and the air supply path 302a connected to the switching valve 202c is connected only to the pressure receiving portion of the pneumatic switching valve 203. May be. However, in FIG. 6, the same parts as those in FIG. 4 are designated by the same reference numerals. In the case of FIG. 6, an air supply passage 301a is connected to both the flow rate adjusting valves 207a and 202a of the delay timer valve device 207 and the idle timer suction time setting delay timer valve device 202. Therefore, as shown in FIG. 5, in order to cause the air to be blown out from the nozzles 13a and 15a and the operation of the first air cylinder 16 after a predetermined time T ₂ has elapsed after the suction time T ₁ from the suction port 14a has elapsed. Adjusting the flow rate adjusting valve 207a of the delay timer valve device 207 so as to switch to the side connecting the air supply paths 301a and 304 after T ₁ + T ₂ after the switching valve 207c is air-fed to the flow rate adjusting valve 207a. There is a need to. Therefore, in the pneumatic circuit shown in FIG. 6, when the suction time T ₁ is changed by adjusting the flow rate adjusting valve 202a of the delay timer valve device 202, the flow rate adjusting valve 2 of the delay timer valve device 207 is changed.
If you leave the 07a, to change the predetermined time T _2, case by changing the suction time T ₁ the predetermined time T ₂ are to be kept constant, together with the to adjust the flow rate regulating valve 202a It is also necessary to adjust the flow rate adjusting valve 207a.

Next, FIG. 7 is a block diagram showing a structure in which the shuttle valve 217, the pneumatic switching valves 218, 221, the pilot air supply source 113 and the air supply passage 310 are removed from the pneumatic circuit shown in FIG. An air supply passage 308a instead of the air supply passage 308 of FIG. 4 is connected to the switching operation section of the pneumatic switching valve 216, and the flow rate adjusting valve 219a and the switching valve 219c of the delay timer valve device 219 for setting the cutting start time are connected. Also shows an air circuit diagram directly connected, and the other parts in this air circuit diagram are denoted by the same reference numerals as those in FIG. In the air circuit diagram of FIG. 7, after driving the sewing machine to press the plunger 215a of the pilot air supply switching valve 215,
When the driving of the sewing machine is stopped and the pressing force on the plunger 215a is released, the fly will not be fed into the air supply passage 308a regardless of the progress of the process. Therefore, each time the sewing machine is driven, the second air cylinder 23 is driven, and in the case where seams are continuously formed on a plurality of edges of one piece of cloth, seams are formed on the second and subsequent edges. The second air cylinder 23 will operate unnecessarily. However, the pneumatic circuit shown in FIG. 7 still has the function of the present invention.

As is clear from the description of FIGS. 6 and 7 above, in performing the function of the present invention, the area difference double pilot valve 206 is removed from the pneumatic circuit of FIG. 4 as shown in FIG. Moreover, as shown in FIG. 7, a shuttle valve 217, pneumatic switching valves 218, 221, a pilot air supply source.
It is also possible to use a pneumatic circuit excluding 221 and the air passage 310.

Next, FIG. 8 shows another embodiment of the empty chain stitching device for an overlock sewing machine according to the present invention. In this embodiment, instead of the suction tube 14 arranged in the cross plate 1 in FIG. 1, the suction tube 1 is placed on the work surface 1a.
4'is provided, and the suction port 14a 'of this suction tube 14' is
It is arranged so that it can be arranged in the vicinity of the suction hole 11a of the air ring cutting portion 10 and on an extension line along the sewing axis X extending from the apex of the tongue 5. By doing so, it is not necessary to form a hole for the suction port in the cross plate 1 as in the case shown in FIG. 1, but it does not interfere with the passage of the cloth when sewing the cloth. It is necessary to move the suction tube 14 'from above the work surface 1a. Connect this suction tube 14 'to the work surface 1a.
The means for moving the suction tube 14 'from the top to a position that does not interfere with the passage of cloth may be such that the suction tube 14' is slid back from the work surface, or the suction port 14'a.
The suction tube 14 'may be rotated about a predetermined position so as to draw an arc. In this way, when arranging the suction port 14'a on the work surface 1a,
It is necessary to move the suction tube 14 'onto the work surface 1a only when suctioning. To perform this automatically, for example, in the pneumatic circuit diagram shown in FIG. 4, by pressing the operating portion 201a of the pilot air supply switching valve 201, the air supply source 103 for the air suction and the suction tube 14 '. When the suction tube 14 'is moved to a predetermined position on the work surface 1a at the same time, the suction tube 14' is disconnected from the suction air supply source 103 and the suction tube 14 'on the work surface 1a. It is sufficient to add a circuit configuration for moving the fabric from the place where it does not hinder the passage of the cloth.

In addition, it goes without saying that the air chain sewing device for an overlock sewing machine according to the present invention is not limited to the above-mentioned embodiment. For example, in the above-mentioned embodiment, a pneumatic circuit is used, but an air cylinder or the like is used instead. A solenoid or the like may be used to operate the device by an electric circuit, or a hydraulic circuit may be used or each of the circuits may be used in combination.

〔The invention's effect〕

As is clear from the above description, according to the empty-loop sewing-in device of the overlock sewing machine according to the first aspect of the present invention, the upper surface of the plate that holds the empty ring is flush with the work surface. Therefore, the holding plate does not interfere with the cloth inserted on the needle plate from the front side of the sewing machine, and it hinders the straight cloth from being fed or damages the quality of the product. There is no effect.

Further, according to the pneumatic loop sewing-in device of the overlock sewing machine according to the second aspect of the present invention, in addition to the effect obtained by the first aspect of the above-mentioned patent claim, the clamped second circular loop is provided. By moving the first and second holding plates together with the movement of the holding plate, the first and second holding plates are moved to the cutting edge portion of the second cutting device to cut between the needle drop portion and the holding portion. The length of the hollow ring sewn into the seam can be appropriately changed depending on the product.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a chain stitching device for an overlock sewing machine according to the present invention, and FIGS. 2A to 2C are cross plates for explaining the operation of a holding plate. Notched plan view, FIGS. 3A to 3
FIG. F is a perspective explanatory view showing a process of treating an empty ring by the embodiment apparatus, FIG. 4 is a view showing an example of a pneumatic circuit of the embodiment apparatus,
5 is a timing chart showing the operation of the pneumatic chain stitching device according to the pneumatic circuit diagram of FIG. 4, FIG. 6 is a diagram showing a modified example of the pneumatic circuit, and FIG. 7 is another modified example of the pneumatic circuit. 8 and 9 are partially cutaway perspective views showing another embodiment of the present invention. 1a ... Working surface 4 ... Needle drop portion 7 ... Clamping plate 71 ... Clamping plate 71 ... Clamping plate 72a ... Suction plate 11a ... Suction hole 12 ... First cutter 15a ... Nozzle (air outlet) 30 ... Second cutting Instrument H ... Insertion port X ... Sewing axis

Claims (2)

[Claims] 1. An overlock sewing machine which forms a seam by overlock stitching at an edge of a fabric and creates an empty ring continuous with the seam at an end of the fabric, the empty ring being provided rearward of a needle drop portion. The air ring sucked into the suction hole and cut by a cutter in the suction hole, and the free end of the air ring separated from the cloth by this cutting is moved by wind pressure to the front side of the needle drop portion, and this air ring has moved. It is provided on the front side of the needle drop section in the empty ring sewing machine of the overlock sewing machine in which the clamp is clamped on the front side of the needle drop section and the clamped loop is sewn into the seam formed on the next fabric. The upper surface is flush with the working surface of the sewing machine and the insertion end into which the free end of the air ring moved by the wind pressure can be inserted is moved in the direction intersecting the sewing shaft so as to form on the working surface. It is provided with a movable holding plate and an air blowing port provided above the insertion port toward the insertion port side formed by the movement of the holding plate, and is emptied by the air blown from the air blowing port. After inserting the free end of the ring into the insertion port,
An empty-loop sewing-in device for an overlock sewing machine, characterized in that the empty ring is clamped on the front side of the needle drop portion by moving the holding plate to close the insertion opening. 2. An overlock sewing machine which forms a seam by overlock stitching at the edge of the fabric and creates an empty ring continuous with the seam at the end of the fabric. The empty ring is provided rearward of the needle drop portion. The air is sucked into the suction hole and cut by the first cutter in the suction hole, and the free end of the empty ring separated from the cloth by this cutting is moved by wind pressure to the front side of the needle drop portion, and this movement is performed. In the over-loop sewing machine's empty-loop sewing-in device, in which the empty loop is clamped on the front side of the needle drop section and the clamped empty loop is sewn into the seam formed on the next cloth, in front of the needle drop section. Side that intersects with the sewing shaft so as to form an insertion port on the work surface where the free end of the empty ring that has been moved by wind pressure can be inserted, and the top surface is flush with the work surface of the sewing machine. The first holding plate movable in the direction and the first holding plate are movable in a direction intersecting with the sewing shaft while being in close contact with the first holding plate only when the first holding plate is driven, and only the first holding plate moves. A second nipping plate that forms the insertion opening with the first nipping plate, and an air blower provided above the work surface toward the insertion opening side formed by the movement of the first nipping plate. A second cutting device provided between the needle drop portion and the first holding plate, and the free end of the empty ring is inserted into the insertion port by the air blown from the air blowing port. Then, the first clamping plate is moved to close the insertion opening to clamp the empty ring by the first and second clamping plates, and in the empty ring clamping state, the first clamping plate and the second clamping plate are played. By moving the second cutting device to the cutting edge portion of the second cutting device so that the second cutting device cuts the empty ring between the needle drop portion and the holding portion. An empty chain stitching device for sewing machines.