JPH0634872B2 - 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 possible to change the length of the empty ring sewn into the seam of the fabric without causing any trouble in the insertion or the feeding of the fabric. An object of the present invention is to provide an empty chain stitching device for an overlock sewing machine.

[Means for Solving the Problems] In order to achieve the above object, an empty ring sewing-in device for an overlock sewing machine according to the present invention is provided on the front side of a needle drop portion and has an upper surface which is a work surface of the sewing machine. Sewn to form on the work surface an insertion port into which the free end of the air ring moved by wind pressure after being cut by the first cutting device on the same plane as and behind the needle drop portion can be inserted. A first holding plate movable in a direction intersecting with the shaft, and a first holding plate movable in a direction intersecting with the sewing shaft in a state of being closely attached to the first holding plate only when the first holding plate is driven. A second holding plate that forms the insertion opening with the first holding plate when only the plate moves, and an air suction opening below the insertion opening that is formed by the movement of the first holding 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 sucked into the air suction port. After that, the first clamping plate is moved to close the insertion opening, so that
While sandwiching by the second sandwiching plate and moving the first sandwiching plate and the second sandwiching plate together in the empty ring sandwiching state, the empty ring is moved to the cutting edge portion of the second cutter and the empty ring is moved. It is characterized in that the ring is cut between the needle drop portion and the sandwiching portion.

[Operation] The overlock sewing machine empty chain stitching device of the present invention is
The free end of the empty ring that has been moved by the wind pressure after being cut by the first cutting device behind the needle drop portion is formed by the movement of the first holding plate by the air sucked into the air suction port. By being introduced into the mouth and then closing the insertion opening by moving the first holding plate,
The empty ring is clamped by the first and second clamping plates in front of the needle drop portion. Here, the upper surface of the first holding plate is flush with the working surface of the sewing machine, and therefore
The clamping plate does not prevent the insertion of the next cloth from the front side. Further, the sandwiching plate is composed of a first sandwiching plate and a second sandwiching plate, sandwiches an empty ring between the first and second sandwiching plates, and further drives the second sandwiching plate to form the first sandwiching plate. Second empty ring sandwiched between
The cutting device of No. 2 cuts between the needle drop portion and the holding portion.

〔Example〕

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

1 to 4F, 1 is a cross plate of an overlock sewing machine, and a work plate 1a of the cross plate 1 is fitted with a needle plate 2 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.
It should be noted that X shown by a chain line in FIGS. 3A to 3C 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 86. The presser foot 86 swings by operating the air pump 8c, and the presser foot 8a moves 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, which is parallel to the sewing axis X and is spaced from the sewing axis X by a predetermined distance.

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 4F) in parallel with the suction passage 11 is disposed on the back 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 work 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 4F) 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.

Below the insertion port H formed by driving the first holding plate 71, a suction port 15 of a suction tube 15 connected to an air suction source (not shown in FIGS. 1 to 4F).
As shown in FIG. 2, a is open upward, that is, facing the insertion port H side.

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.

A compression spring 27 is stretched between the spring receiving concave portion 26a formed in the spring receiving base 26 and the spring receiving concave portion 72aa formed in the operating piece 72a, and the operation piece 72a is urged by the compression spring 27. Is urged toward the contact member 24. On the other hand, the abutting member 24 and the bracket 17 integrated with the abutting member 24 are formed with a cutout portion 28 that opens to a contact surface with the operation piece 72a. The tip of the swing arm 29 that transmits the operation is inserted. The swing arm 29 is formed in an L-shape, and a corner portion 29a thereof is rotatably supported, and an upper end portion of one side rising from the corner portion 29a has a cutout portion as described above.
Inserted in 28. A piston rod 23a for advancing and retreating in the vertical direction of the second air cylinder 23 is provided at the tip of one side extending laterally from the corner portion 29a of the swing arm 29.
A rod receiver 29b is formed so as to abut with. 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 manner, the second holding plate 7 formed integrally with the operation piece 72a is formed.
2 to the side of the first holding plate 71, the first holding plate 71
Move with. At this time, it goes without saying that the first holding plate 71 moves against the biasing force of the compression spring 20. When the piston rod 23a of the second air cylinder 23 is retracted, the tip of the swing arm 29 returns to the inside of the notch 28, so that the operating piece 72a is urged by the compression spring 27 to contact the contact member 24. At the same time, the second holding plate 72 comes into contact with the needle plate 2 on the sewing shaft X at the same time. Further, when the second holding plate 72 moves in such a manner as to come into contact with the needle plate 2 on the sewing shaft X, the first holding plate 71 is also moved by the urging force of the compression spring 20.
It moves to the sewing axis X side together with the second holding plate 72.
Therefore, when the second air cylinder 23 is operated, the first air cylinder 23
The 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 cloth edges prior to overedging and the function of cutting the empty ring as described below. As shown in FIG. 3C, the first holding plate 71 and the second holding plate are shown. It is provided on the movement locus of the empty ring Ch sandwiched between the two when the 72 moves together to the first holding plate 71 side. Further, the movable blade 30b crosses each cutting edge by performing a reciprocating motion centering on the rear side of the fixed blade 30a in synchronization with the driving of the sewing machine, whereby the empty ring Ch is moved as shown in FIG. 3C. 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. 5 and the schematic diagrams for explaining the operation process shown in FIGS. 4A to 4F.

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, since the air suction source 101 (shown only in FIG. 5) connected to the suction passage 11 is activated when the sewing machine is driven, 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. 4A 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. 4A, 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.

In this way, when the plunger 201a of the pilot air supply switching valve 201 is pressed, as is clear from FIG. 6,
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. 6 is determined by adjusting the flow rate adjusting valve 202a. As shown in FIG. 6, 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 pilot valve. Among the pressure receiving portions of the area difference double pilot valve 206, the air supply passage 302 is connected to the first pressure receiving portion 206a having a large cylinder diameter, and the second pressure receiving portion having a small cylinder diameter is connected. An air supply path is provided in the 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 passage 301 is being sent to the air supply passage 302 via the switching valve 202c, the area difference double pilot valve 206 is connected to the air supply passage 301 and the air supply passage 303. Located on the side where the connection is cut off, the switching valve
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 pilot air to the air supply passage 303 at the time point t ₁ (see FIG. 6) 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 supplies the air to the air supply passage 307 to suck the air suction source 110 to the suction side. Switch to the side connected to tube 15.

In this way, the pneumatic switching valves 211 to 213 are switched, air is supplied from the driving air supply sources 108 and 109, and the air suction source 110 sucks the air.
At the same time as the air is blown out from the nozzle 13a of No. 3, the first air cylinder 16 is actuated, the piston rod 16a is extended, and the air is sucked into the suction port 15a of the suction tube 15. That is, the air is blown from the nozzle 13a, the piston rod 1
The stretching of 6a and the suction of air into the suction port 15a simultaneously start at time t _{2 as} shown in FIG. Further, as is clear from the above description, the time T ₃ during which air is blown out from the nozzle 13a, the time T ₄ during which the piston rod 16a is driven toward the extending side, and the air is sucked into the suction port 15a. The time T ₅ is 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. 4C, 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 front side of the sewing machine shown in FIG. 3B. And as shown in FIG. 4D, the hollow ring insertion port H
Is formed, and the air ring Ch is introduced into the insertion port H by the air sucked into the suction port 15a. As described above, the time T ₅ for sucking air into the suction port 15a is set longer than the time T ₄ for driving the first air cylinder 16 because the driving air supply source is used.
It takes time from when the connection between 109 and the first air cylinder 16 is cut off until the piston rod 16a retracts and the insertion port H is closed. During this time, air is also supplied to the suction port 15a. By inhalation, as shown in Fig. 4E,
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. 4E, 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 suction source 101 and the suction passage 11 when air is sent to the switching operation portion. In this way, the air suction 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 which is connected to the rear end of the fabric and has a length reaching the suction hole 11a from the tongue 5 is always sucked into the suction hole 11a, and as described above with reference to FIG. It will be cut.

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 FIG. 3C and FIG. 4F, the empty ring Ch is moved to the side closer to the second cutting device 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 joining the seam to the end of the previous cloth is separated by the first cutting device 12, moved to the front side of the needle drop portion 4 and clamped, and the tip of the next cloth is cut. 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 of the overlock sewing machine according to the present invention, as shown in FIG. 7, the area difference double pilot valve 206 is removed from the pneumatic circuit shown in FIG. An air supply path 301 that is connected to the switching valve 201 and replaces the air supply path 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. 7, the same parts as those in FIG. 5 are designated by the same reference numerals. In the case of FIG. 5, 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. 6, after a predetermined time T ₂ has elapsed after the suction time T ₁ from the suction port 14a, the air is blown from the nozzle 13a, the operation of the first air cylinder 16 and the suction port.
In order to allow air to be sucked into 15a, the flow rate adjusting valve 207a of the delay timer valve device 207 is connected to the air supply path 301a after T ₁ + T ₂ after the switching valve 207c is fed into the flow rate adjusting valve 207a. It is necessary to adjust to switch to the side to connect 304. Therefore, in the pneumatic circuit shown in FIG. 7, 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 207a of the delay timer valve device 207 is left as it is. If you put
Since the predetermined time T ₂ also changes, if it is desired to keep the predetermined time T ₂ constant even if the suction time T ₁ is changed, the flow rate adjusting valve 202a is adjusted together with the flow rate adjusting valve 202a. It is necessary.

Next, FIG. 8 is a 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, which is an alternative to the air supply passage 308 of FIG. 5, is connected to the switching operation section of the pneumatic switching valve 216, and the flow control 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 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. 8, 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, air is not sent to the air supply passage 308a regardless of the progress of the process. Therefore, every time the sewing machine is driven, the second air cylinder 23 is driven, and when seams are continuously formed on a plurality of edges of one piece of fabric, when the seams are formed on the second and subsequent edges. The second air cylinder 23 will operate unnecessarily. However, the pneumatic circuit shown in FIG. 8 still has the function of the present invention.

As is clear from the description of FIGS. 7 and 8 above, in carrying out the operation of the present invention, the area difference double pilot valve 206 is removed from the pneumatic circuit of FIG. 5 as shown in FIG. Moreover, as shown in FIG. 8, 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. 9 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 14'a of this suction tube 14 '
Can be arranged in the vicinity of the suction hole 11a of the empty 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. The means for moving the suction tube 14 'from above the work surface 1a to a place where it does not interfere with the passage of cloth may be such that this suction tube 14' is slid back from the work surface, or the suction port 1
The suction tube 14 'may be rotated around a predetermined position so that 4'a draws an arc.
In this way, when the suction port 14'a is arranged on the work surface 1a, it is necessary to move the suction tube 14 'onto the work surface 1a only during suction. 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 '. The suction tube 14 'is moved to a predetermined position on the work surface 1a at the same time when the suction tube 1'is connected, and the suction tube 14' is disconnected from the air supply source 103 for the air suction.
It suffices to add a circuit configuration for moving 4 ′ from above the work surface 1a to a place where it does not interfere with the passage of the cloth.

Incidentally, it goes without saying that the pneumatic ring stitching device according to the present invention is not limited to the above-mentioned embodiment, and for example, in the above-mentioned embodiment, a pneumatic circuit is used, but instead of the air cylinder or the like, a solenoid or the like is used. The device may be operated 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 apparent from the above description, according to the empty ring sewing device of the overlock sewing machine of the present invention, since the upper surface of the plate that holds the empty ring is flush with the work surface of the sewing machine, the holding plate is It does not interfere with the insertion of the cloth that is inserted on the needle plate from the front side of the sewing machine, and it hinders the straight insertion of the inserted cloth, or damages the cloth, thus impairing the quality of the product. Never. Moreover, the sandwiched empty ring is moved to the blade edge portion of the second cutter by the movement of the second sandwiching plate so as to cut between the needle drop portion and the sandwiching portion. The effect that the length of the hollow ring sewn into can be appropriately changed depending on the product is obtained.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of an empty chain stitching device for an overlock sewing machine according to the present invention, FIG. 2 is a partial schematic sectional view, and FIGS. 3A to 3C are the same. FIG. 4A to FIG. 4F are perspective explanatory views showing a process of processing an air ring by the embodiment apparatus, and FIG. 5 is a pneumatic circuit of the embodiment apparatus for explaining the operation of the holding plate. The figure which shows an example, FIG. 6 is a timing chart figure which shows operation | movement of the pneumatic chain sewing device by the pneumatic circuit diagram of FIG. 5, FIG. 7 is a figure which shows the modification of a pneumatic circuit,
FIG. 8 is a view showing another modification of the pneumatic circuit, and FIG. 9 is a partially cutaway perspective view showing another embodiment of the present invention. 1a ... Working surface 4 ... Needle drop portion 7 ... Clamping plate 71 ... Clamping plate 72 ... Clamping plate 72a ... Suction plate 11a ... Suction hole 12 ... First cutter 15a ... Suction port 30 ... Second cutter H ... Insertion Mouth X ... Sewing axis

Claims (1)

[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 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. And a first nipping plate that is movable in a direction intersecting the sewing shaft while being in close contact with the first nipping plate only when the first nipping plate is movable. A second sandwiching plate that forms the insertion opening between the first sandwiching plate and the first sandwiching plate when moved, an air suction port formed below the insertion slot formed by the movement of the first sandwiching plate, and a needle A second cutting device provided between the drop portion and the first holding plate, and after inserting the free end of the empty ring into the insertion port by the air sucked into the air suction port, Clamping the empty ring by the first and second sandwiching plates by moving the sandwiching plate and closing the insertion port, and moving the first sandwiching plate and the second sandwiching plate together in the empty ring sandwiching state. More,
An empty ring sewing device for an overlock sewing machine, characterized in that an empty ring is moved to a cutting edge portion of a second cutting device to cut the empty ring between a needle drop portion and a holding portion.