JPH06296787A - Empty ring sewing device for overlock sewing machine - Google Patents

Abstract

PURPOSE:To provide an empty ring sewing device for overlock sewing machine in which a state such that an empty ring cut end penetrates between a presser foot and a throat plate to prevent the sure empty ring sewing operation is never caused, and beautiful back tucking can be surely performed. CONSTITUTION:A blowing pipe 8 for blowing an air flow comparatively weaker than the blowout air flow generated in an air passage 10 to the periphery of a needle falling point is provided substantially on the right side of the needle falling point, and the blowout air flow is turned on the side where a locking member 26 and a tension imparting member 35 are situated by this air flow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overlock sewing machine for a backtack sewing, which is capable of sewing back chain.

[0002]

2. Description of the Related Art Conventionally, an overlock sewing machine capable of backtack sewing is disclosed in, for example, Japanese Patent Laid-Open No. 3-9969.
As described in Japanese Patent Publication No. 3, an empty ring holding mechanism for holding an empty ring of a thread connected to a needle is provided on a cloth feeding side from a needle drop point, and an empty ring of a thread connected to a needle cut by a cutting device is provided. There is a structure in which the air ring is held by the air ring holding mechanism by moving the air ring toward the cloth feeding side from the needle drop point by the jet air flow.

[0003]

However, when the empty loop of the yarn connected to the needle cut by the cutting device moves toward the cloth feeding side from the needle drop point by the jet air flow, the empty ring cut end is It may get in between the presser foot and the needle plate and get caught by the presser foot or the claw of the needle plate.In such a case, the empty ring is not held by the empty ring holding mechanism and the sewing operation of the empty ring is reliable. There is a problem that it is not done. The present invention is
In order to solve the above-mentioned problems, the cut end of the hollow ring does not enter between the presser foot and the throat plate, and the sewing operation of the hollow ring is not reliably performed. An object of the present invention is to provide an empty-loop sewing-in device of an overlock sewing machine capable of sewing.

[0004]

In order to achieve the above object, the present invention provides a suction device for sucking an empty ring of a thread connected to a work cloth toward the cloth feed-out side from a needle drop point at the end of sewing, and a suction device therefor. A cutting device that cuts the empty ring sucked by the suction device, and a moving unit that moves the empty ring of the yarn connected to the needle cut by the cutting device to the cloth feeding side from the needle drop point by the jet air flow, In an empty-loop stitching device of an overlock sewing machine, which is provided with empty-loop holding means for holding the empty ring moved by the moving means, a blowing means for blowing an air flow from around the right side of the needle drop point to the vicinity of the needle drop point. The air flow ejected by the moving means is swirled to the side of the empty ring holding means by the air flow blown from the blowing means.

[0005]

According to the above construction, the empty loop of the yarn which is connected to the needle cut by the cutting device moves to the cloth feeding side from the needle drop point by the jet air flow, but at this time, the blowing means drops the needle. Blow an air stream around the needle drop point from approximately the right side of the point. This air flow causes the jet air flow to swirl toward the side of the empty ring holding means that holds the empty ring, and the cut end of the empty ring draws an arc about the needle drop point along this air flow. Thus, the empty ring holding means is moved and held. This ensures that the empty chain stitching operation is performed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are partially cutaway plan views of a two-needle overlock sewing machine according to this embodiment. On the work cloth supporting surface 2 of the bed portion 1 of the sewing machine main body, needle passing holes 3a and 3d through which the left and right two needles 5a and 5b pass, an opening 3c for the feed dog, and a needle plate outer claw 3b for forming a thread loop. And needle plate middle claw 3e
The needle plate 3 having the is arranged. Above the needle plate 3,
A presser foot 4 for pressing the work cloth is disposed on the work cloth supporting surface 2, and a presser foot middle pawl 4a and a presser foot outer pawl 4b are formed on the presser foot 4. On the other hand, below the needle plate 3, a feed dog 6 which is projected and retracted on the needle plate 3 through the feed dog opening 3c is provided.

A cutter device 7 having a pair of cutting blades 7a and 7b for cutting the edges of the work cloth prior to forming the stitches is attached to the bed portion 1 on the cloth feeding side from the needle drop point. Has been done. Further, on the cloth feeding side with respect to the needle drop point, the bed 1 is mounted with a support 11 having an air passage 10 extending substantially along the cloth feeding direction, and the upper surface thereof is covered with a cover 12. At the rear end (not shown) of the air passage 10, a suction pipe (not shown) for generating an intake air flow for sucking the empty ring R of the yarn connected to the end of the work cloth in the air passage 10, A jet pipe (not shown) that generates a jet air flow for blowing the air ring R back to the cloth feeding side is provided in the air passage 10.

Inside the cover 12, the fixed blade 1 is provided in the vicinity of the opening 10a of the air passage 10 which diffuses in a trumpet shape.
3, and an air ring cutting device 15 composed of a reciprocating movable blade 14 is arranged, and the air ring R sucked into the air passage 10 is cut by the cooperation of the fixed blade 13 and the movable blade 14. It is supposed to be done. In addition, this empty ring cutting device 15
Has the same structure as that described in Japanese Utility Model Publication No. 58-22705. Further, on the substantially right side of the needle drop point, a blowing pipe 8 for blowing an air flow relatively weaker than the air flow ejected from the ejection pipe around the needle drop point is provided.

On the cloth feeding side of the needle plate 3, an air ring holding means is provided below the bed portion 1. The structure will be described with reference to FIGS. 1 to 4. In the support member 20 provided upright on the bed portion 1, a pair of elongated holes 2 extending in the left-right direction is provided.
The slide plate 22 having the number 3 is supported by the elongated hole 23 and the pair of shafts 21 provided in the support member 20 so as to be slidable in the left-right direction. A cutting air cylinder 24 is provided at the left end of the support member 20, and the tip of the piston 24 a is connected to one end of the sliding plate 22. Therefore, the sliding plate 22 is arranged at the right end position when the piston 24a of the cutting air cylinder 24 is projected, and is located at the left end position when the piston 24a is retracted (see FIG.
(Solid line position).

As shown in FIG. 3, a support block 25 is provided at the upper right end of the sliding plate 22 so as to be slidable together with the sliding plate 22, and a recess 25a is formed in the upper surface thereof.
Are formed. At the upper rear end of the support block 25,
The locking member 26 is rotatably supported by a shaft 27.
The locking member 26 is formed with a locking piece 26 a extending above the support block 25 and a forked portion 26 b arranged on the right side surface of the support block 25. The locking member 26 lies in the recess 25a of the support block 25 and is positioned inside the work cloth support surface 2, and the hollow ring R is recessed in the recess 25a.
3a and the locking position (the position shown by the alternate long and short dash line in FIG. 3) for locking onto the workpiece a, the locking piece 26a is separated from the recess 25a and protrudes onto the work cloth supporting surface 2, and the air flow from the air passage 10 is ejected. And a restricting position (a solid line position in FIG. 3) for restricting the position of the empty ring R by abutting the empty ring R blown back to the cloth feeding side by the air flow from the blowout pipe 8. There is.

A thread gripping air cylinder 30 is mounted on a projecting portion 25b provided on the lower front surface of the support block 25, and a coupling tool 31 having an engaging pin 31a is mounted on a piston 30a thereof. . Also, the support block 25
A connecting link 28 is rotatably supported by a shaft 29 at the central portion on the right side surface of the central portion. The connecting link 28 has a forked portion 28a formed at the front end thereof to engage with the engagement pin 31a of the connecting tool 31, and an engaging projection 28b is provided at the rear end portion thereof so that the forked portion of the locking member 26 is provided. Two
6b is engaged. Then, the thread gripping air cylinder 30
When the piston 30a is retracted, the locking member 26 is arranged at the restricting position via the connecting tool 31 and the connecting link 28, and when the piston 30a is projected, the locking member 26 is arranged at the locking position.

On the other hand, on the upper left side surface of the support block 25, as shown in FIG. 4, a tension applying member 35 is rotatably supported by a shaft 36. At the side edge of the tension applying member 35, an engaging portion 35a that engages with the empty ring R locked on the recess 25a by the locking member 26 is formed.
In addition, a projecting piece 35b located outside the locking piece 26a of the locking member 26 is formed at the tip portion thereof. further,
The tension applying member 35 is provided with an engagement protrusion 35c that protrudes into a notch recess 25c formed in a notch on the upper left side surface of the support block 25. This tension applying member 3
5 protrudes above the work cloth supporting surface 2 and the protrusion 3
5b is a locking piece 2 of the locking member 26 arranged at the regulating position.
6a and the retracted position (the position shown in FIG. 3 to FIG. 5) arranged rearward, and the locking member 26 is laid down in the recessed position 25a of the support block 25 in the locked position and locked. Engagement in which the empty ring R locked by the member 26 is further pushed from the initial locking position toward the cloth feeding side by the engagement between the empty ring R and the engaging portion 35a to give tension to the empty ring R. It is arranged so that it can be switched to the position (the position shown in FIG. 6).

Further, on the left side surface of the support block 25, an operating scale 37 can be moved up and down through the engagement of a long hole 37a formed therein and a shaft 38 protruding from the left side surface of the support block 25. Supported by. A transmission member 40, which is movable in the cutout recess 25c of the support block 25, is attached to the upper end of the operating scale 37, and the forked portion 40a formed at the tip of the transmission member 40 applies tension to it. Member 35
Is engaged with the engaging projection 35c. On the other hand, the lower end of the operating scale 37 is connected to a piston 39a of a tensioning air cylinder 39 provided on the sliding plate 22. Then, when the piston 39a of the tension applying air cylinder 39 is projected, the operating scale 37 and the transmission member 40 are integrally moved upward, and based on the engagement between the bifurcated portion 40a of the transmission member 40 and the engagement protrusion 35c, the tension applying member. 35 is arranged in the retracted position.

Further, when the piston 39a of the tensioning air cylinder 39 is retracted in the state where the locking member 26 is arranged at the locking position (the state shown in FIG. 5), the working scale 37 and the transmission member 40 are integrated. 4 and is arranged at the position indicated by the chain double-dashed line in FIG. 4, and the tension applying member 35 is arranged at the engagement position, as shown in FIG. At this time, the tension applying member 3
A gap is maintained between the protruding piece 35b of No. 5 and the locking piece 26a of the locking member 26, and even if the tension applying member 35 is at the engaging position, the locking member 26 moves a few times within the range of the clearance. It can be moved, and the lock of the empty ring R can be loosened.

Further, in the sewing machine of the present embodiment, as shown in FIG.
As shown in, a needle bar 5 in which a left needle 5a and a right needle 5b are fitted is provided above the needle plate 3 so as to be movable up and down. By moving the needle bar 5 up and down, the left needle 5a is moved. 5a passes through the left needle passage hole 3a, and the right needle 5b passes through the right needle passage hole 3d. The yarn guide 74 and the yarns Y1 and Y2 are provided on the yarn feeding side of the needle bar 5.
Thread tension adjusters 82, 84 and the like for adjusting the tension of the thread when forming the ground stitch and when forming the empty ring are provided.
4 and a thread tension adjuster 82, a thread loosening device 80 is arranged. The thread loosening device 80 is a thread loosening air cylinder 76.
The yarn Y1 supplied from a thread spinning machine (not shown) passes through the thread tension adjuster 82, the thread loosening device 80, the thread guide 74, etc., to the left needle 5a, and the thread Y2 is It is passed through the tension adjuster 84, the thread guide 74 and the like and passed through the right needle 5b.

On the other hand, in the vicinity of the needle drop point, an upper looper 72 and a lower looper 70 (the lower looper 70 is lower than the needle plate 3) which are rotated by the sewing machine drive shaft are arranged. The yarn Y3 is passed through the upper looper 72. Then, the work cloth on the work cloth support surface 2 is fed in the direction of arrow P in FIG. 1 by the cooperation of the feed dog 6 and the presser foot 4, and the needles 5a and 5b, the upper looper 72, and the lower looper accompanying this are fed. In cooperation with 70, overlock seams are formed along its edges.

Next, the shape of the needle plate 3 will be described in detail with reference to FIGS. 1 and 2 and FIGS.
Has a length shorter than that of the needle plate outer claw 3b, and the hollow ring R is shown in FIG.
When pulled by an appropriate force in the direction of arrow P, the left needle 5
The yarn Y1 of a is formed to have a length that allows the yarn Y1 of a to move from the left needle passage hole 3a to the right needle passage hole 3d. On the other hand, as shown in FIG. 9, the presser foot middle claw 4a has a length of the needle plate middle claw 3a.
It is formed to be shorter than e and has the outer claw 4 of the presser foot 4.
The presser foot middle claw root 4c on the side opposite to the b side is located at substantially the same position as the needle plate middle claw root 3g on the side opposite to the outer claw 3b side of the needle plate 3. Further, the presser foot outer nail base 4d on the side of the middle pawl 4a of the presser foot 4 is located closer to the needle passing position of the right needle 5b than the needle plate outer nail base 3f on the side of the middle pawl 3e of the needle plate 3 is. Along with
The presser foot is located closer to the needle passing position than the nail base 4c. Accordingly, when the presser foot 4 is installed, it can be easily installed at a specific position by simply aligning the presser foot middle nail base 4c with the needle plate middle nail base 3g. In addition, a loop formed by the yarn Y1 described later can be reliably formed.
As shown in FIG. 8, the empty ring guide groove 94 is provided at the right end of the needle plate 3.
Is formed, and in the vicinity thereof, the hollow ring R is provided with a hollow ring guide groove 94.
A chamfered portion 92 is provided to guide the operator so that he / she can easily escape from the vehicle.

Next, the structure of the control unit of the sewing machine in this embodiment will be described with reference to FIG. To the CPU 44, a ROM 45 that stores a control program for the sewing machine and a RAM 46 that is a working memory are connected. Further, the CPU 44 has a cutting air cylinder 24,
Thread gripping air cylinder 30, tensioning air cylinder 3
9 and a yarn loosening air cylinder 76 are connected via a cutting valve 47 for opening and closing, a yarn gripping valve 48, a tension applying valve 49, and a yarn loosening valve 86, respectively. Further, it is connected to a sewing machine motor 50 for driving the sewing machine, a suction valve 51 for generating an intake air flow in the air passage 10 for sucking the air ring R, a jet valve 52 for generating a jet air flow, and a blow pipe 8. The blowout valve 88 is connected.

The operation of the sewing machine thus configured will be described. Sliding plate 22 during sewing machine operation
Is arranged at the left end position, and the locking member 26 and the tension applying member 35 are respectively arranged at the locking position and the engaging position, as shown in FIG. Further, an intake air flow is formed in the air passage 10 based on the operation of the suction valve 51. In this state, the work cloth on the work cloth support surface 2 is pressed against the feed dog 6 by the presser foot 4, and is transferred in the direction of arrow P in FIG. After the edges of the cloth are cut, the overlock stitches are formed by the cooperation of the needles 5a and 5b and the upper and lower loopers 70 and 72 at the needle drop point.

When sewing is completed up to the cloth feeding side end of the work cloth, one end is connected to the work cloth and the other end is connected to the needles 5a and 5b through the needle plate outer claw 3b and the needle plate middle claw 3e. An empty ring R is formed. The CPU 44 separates the presser foot 4 upward from the work cloth support surface 2 before stopping the sewing machine motor 50. When the empty ring R reaches a predetermined length,
The air ring R is sucked into the air passage 10 by the intake air flow, the yarn Y1 moves from the left needle passage hole 3a to the right needle passage hole 3d, and in this state, the air ring cutting device 15 is actuated to move the air ring R. Is separated from the work cloth.

After that, the CPU 44 stops the sewing machine motor 50 to stop the operation of the sewing machine at the needle up position, and stops the formation of the suctioned air flow through the suction valve 51. At this time, since the lower looper 70 rotates from left to right and stops, the yarns Y1 and Y2 connected to the empty loop R scooped by the lower looper 70 are carried to the right outer side of the needle plate outer claw 3b ( (R 'position in FIG. 2). Further, the CPU 44 causes the piston 39a of the tension applying air cylinder 39 to project through the tension applying valve 49, and arranges the tension applying member 35 in the retracted position. Further, the CPU 44 immerses the piston 30a of the yarn gripping air cylinder 30 via the yarn gripping valve 48, disposes the locking member 26 in the regulating position, and locks the locking piece 2 thereof.
6a is projected above the work cloth supporting surface 2.

Subsequently, the CPU 44 forms a jet air flow in the air passage 10 via the jet valve 52. This air flow follows the shape of the opening 10a that expands into a trumpet shape,
It is ejected in the direction of arrow A in FIG. At the same time,
An air flow relatively weaker than the jet air flow is blown from the blow pipe 8 through the blow valve 88 around the needle drop point in the direction of arrow C in FIG. Due to this weak air flow, a negative pressure is generated around the blowing pipe 8, and the jet air flow jetted in the arrow A direction changes from the arrow A direction to the arrow B direction. As a result, the cut end of the empty ring R moves from the direction of arrow A to the direction of arrow B so as to draw an arc around the needle drop point.
The movement of the moved empty ring R is restricted by the locking piece 26a of the locking member 26, and the empty ring R is positioned on the recess 25a. After a predetermined time from the generation of the air flow, the CPU 44 stops the formation of the air flow via the ejection valve 52 and the ejection valve 88.

Thereafter, the CPU 44 causes the thread grasping valve 48 to
The piston 30a of the thread-clamping air cylinder 30 is projected through the hook, the locking member 26 is switched from the restricting position to the locking position, and the end of the empty ring R is recessed 25a, as shown in FIG. And the locking piece 26a. Then C
The PU 44 retracts the piston 39a of the tension imparting air cylinder 39 through the tension imparting valve 49, and switches the tension imparting member 35 from the retracted position to the engaged position as shown in FIG. With the switching of the tension applying member 35, the engaging portion 35a of the tension applying member 35 engages with a part of the empty ring R, and the empty ring R is pushed out in the direction away from the needle drop point (see FIG. 2). R ″ position). By this pushing out, the slack of the empty ring R is removed with the locking portion of the empty ring R locked by the locking member 26 as the fixed end, and an appropriate tension is applied to the empty ring R. As a result, the empty ring R is held and securely embedded in the empty ring guide groove 94 as shown in FIG. 8 without flowing onto the cutting edge 7b of the cutter device 7.

In this state, the CPU 44 drives the yarn loosening air cylinder 76 via the yarn loosening valve 86. Then, the yarn loosening device 80 pulls the yarn Y1 out of a yarn spinning machine (not shown) by a predetermined length, and then returns the yarn loosening air cylinder 76 to the original position. As a result, the yarn Y1 is loosened by a predetermined amount on the yarn delivery side of the yarn tension adjuster 82, that is, on the left needle 5a side. Although FIG. 8 shows the case where the yarn connected to the empty ring R is formed in a Y shape by the needle plate outer claw 3b, it is formed on one side surface of the needle plate outer claw 3b in a biased manner. In some cases, the effect of the present invention is not affected even in such a case.

After that, when a new work cloth is placed on the work cloth support surface 2 and the sewing operation is performed again, a new empty ring R is formed until the new work cloth tip reaches the needle drop point. It is formed. When the needle bar 5 is lowered at the first stitch forming the hollow ring R, the loosened yarn Y1 of the left needle 5a is
The needle hole resistance of a forms a loop 90 as shown in FIG. The loop 90 is formed by the presser foot middle claw 4 of the presser foot 4.
It is formed on the right needle 5b side by being guided by a and the root 4d of the presser foot outer pawl 4b. In addition, since the root 4d of the presser foot outer pawl 4b is located close to the needle passing position of the right needle 5b, the loop 90 is stably formed behind the right needle 5b, whereby the right needle 5b is It goes through this loop 90.

The needles 5a and 5b are connected to the needle passage holes 3a and 3
After passing d, the yarns Y1 and Y2 are scooped by the lower looper 70, and the yarn Y1 is held by the yarn Y2 so as to be located behind the right needle 5b. In this state, a new empty ring R is formed behind the needle drop point by sequentially driving the sewing machine. At this time, a new empty ring R or The empty ring R held on the front side is stepped on by the needles 5a, 5b, or the needles 5a, 5b are empty ring R.
It is possible to stably sew the previously formed hollow ring R to the edge of the work cloth without straddling the edge.

After a lapse of a predetermined time from the start of the sewing machine motor 50, the CPU 44 projects the piston 24a of the cutting air cylinder 24 through the cutting valve 47 and moves the support block 25 together with the sliding plate 22 to the right end. Along with this movement, the air ring R located in the air ring guide groove 94
Is guided by the chamfered portion 92 of the needle plate 3 and escapes from the empty ring guide groove 94 without being applied with excessive tension.
Then, the empty ring R is arranged on the cutting edge 7b of the cutter device 7, and the empty ring R is cut simultaneously with the cutting of the work cloth edge by the cutter device 7. In this way, after the length of the hollow ring R sewn into the new work cloth is set to a predetermined length, the sliding plate 2
2, and the support block 25 is returned to the left end.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the present embodiment, the air cylinder is used as the yarn loosening means for the yarn Y1, but an electromagnetic solenoid may be used. It is also possible to open all the thread tension adjusters in the thread Y1 or switch them to an appropriate tension state by a known means.

[0029]

As described above, according to the present invention, when the jet air flow for blowing back the empty ring of the yarn connected to the needle to the cloth feeding side is jetted, the blowing means is located substantially to the right of the needle drop point. By blowing an air flow relatively weaker than the jet air flow around the needle drop point, the jet air flow is swirled to the side of the empty ring holding means that holds the empty ring. Due to this air flow, the cut end of the empty ring connected to the needle does not enter between the presser foot and the needle plate, and the empty ring is drawn along this air flow so as to draw an arc about the needle drop point. It moves to the holding means and is securely held there, whereby the empty chain sewing operation is surely performed.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view of a two-needle overlock sewing machine according to an embodiment of the present invention.

FIG. 2 is a partially cutaway enlarged plan view of the two-needle overlock sewing machine according to the present embodiment.

FIG. 3 is a right side view of the empty ring holding mechanism according to the present embodiment.

FIG. 4 is a left side view of the empty ring holding mechanism according to the present embodiment.

FIG. 5 is an explanatory diagram showing an operating state of the empty ring holding mechanism according to the present embodiment.

FIG. 6 is an explanatory diagram showing an operating state of the empty ring holding mechanism according to the present embodiment.

FIG. 7 is an explanatory diagram showing a state of a thread at the time of sewing.

FIG. 8 is an explanatory view showing a state of holding an empty ring on the needle plate.

FIG. 9 is an explanatory diagram showing loop formation.

FIG. 10 is a block diagram showing a configuration of a control unit according to the present embodiment.

[Explanation of reference numerals] 8 blow-out pipe 15 air-ring cutting device 26 locking member (air-ring holding means) 35 tension applying member (air-ring holding means) 44 CPU 88 blow-out valve Y1 thread Y2 thread R empty ring

Claims (1)

[Claims] 1. A suction device for sucking an empty ring of a thread connected to a work cloth toward the cloth delivery side from a needle drop point at the end of sewing, and a cutting device for cutting the empty ring sucked by the suction device. , Moving means for moving the empty ring of the yarn connected to the needle cut by the cutting device to the cloth feeding side from the needle drop point by the jet air flow, and the empty ring holding for holding the empty ring moved by the moving means An over-locking sewing machine loop stitching device including a means for ejecting an air flow from around substantially the right side of the needle drop point to the vicinity of the needle drop point, and the air flow ejected by the moving means from the blowing means. An air-loop sewing device for an overlock sewing machine, characterized in that it is swung to the side of the idle-loop holding means by an air flow blown thereinto.