JP3391846B2 - Double chain stitch machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-needle, double chainstitch sewing machine, and more particularly to a multi-needle, double chainstitch sewing machine capable of continuously and smoothly drawing an empty ring.

[0002]

2. Description of the Related Art Two or three needles, such as a flat stitch sewing machine and a double chain stitch sewing machine, which do not use a top decoration thread and which are formed of two or three needles and one looper. Double chain stitch of thread or three-needle four-thread (JIS L 0120)
In the sewing machine forming 406 and 407 ), it is important in order to improve the sewing efficiency that the sewing machine is continuously operated to feed the cloth one after another to continuously and smoothly form an empty ring between the cloths.

However, in the above-mentioned conventional type of sewing machine, when one cloth is sent out after sewing, an empty ring formed continuously with the sewing end is pushed down by a needle descending for forming the next stitch. Is hung down below the needle plate,
When the looper goes to scoop the needle thread loop formed on the needle rising from the bottom dead center, it is impossible to feed the empty loop by hooking the hanging empty loop at the same time, and the left and right needle threads must be clothed. Due to the fact that it is not possible to maintain a predetermined interval, stable stitch formation becomes impossible, and it becomes impossible to hold the feed dog at the rear of the stitch forming area in the feed direction and pull it out on the throat plate and feed it out. I can't put out an empty ring.

To solve this problem, Japanese Patent Laid-Open No. 3-23
No. 887 has a tongue protruding from the lower side of the nail formed by a gate-shaped slit extending from the needle hole of the needle plate in the cloth feeding direction, and when the cloth is sewn, the cloth is formed on the tongue. The same type of stitches that are used to hold the empty ring is used to prevent the empty ring from falling due to the needle lowering, and the formed empty ring is arranged in the feed direction and then sent out by the feed dog, A sewing machine designed to produce
For No. 1, when the cloth has been sewn, the tension of the right needle thread of the two needles is released and the right needle thread is brought closer to the left needle thread side by the looper thread, and then backward in the cloth feed direction of the needle hole. A sewing machine has been proposed in which it is fed by a feed dog and an auxiliary feed member after being arranged.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multi-needle double chain stitch sewing machine capable of more reliably withdrawing an empty ring than the above-mentioned conventional ones. .

[0006]

A double chainstitch sewing machine according to the present invention has a plurality of needles which move up and down in a direction orthogonal to the cloth feeding direction and a direction in which the needles are arranged below a needle plate, as shown in the drawing. In a multi-needle, double chain stitch sewing machine that forms a double chain stitch with one looper that swings to the back, it swings in conjunction with the looper (4) and engages with the needle tip when the needle is raised. A loop support (9) that is provided on the needle receiver (7) that performs the needle guiding action and laterally supports the needle thread loop formed on the needle (6), and the tension of the thread tensioner for forming the ground stitch or forming an empty ring. And a needle plate (11), (24) are provided, and the needle plates (11), (24) are formed in the cloth feeding direction and are surrounded by the slit (15). Claw pieces (14), (26), which are notch protrusions (14a), (27), and other portions are notched, and claw pieces (14), (2)
6) Needle holes (1
2), (13), (29) and the rear feed dogs (18), (1) formed behind the slit (15) in the cloth feeding direction and for pulling out the air ring.
9) is arranged, and the feed dog holes (16), (17) and the cross rails (21), (2) between the slit (15) and the feed dog hole (16) are provided.
8) It is characterized in that it has guide grooves (22) and (30) for guiding the air ring formed on the upper surface toward the other side from the center.

According to the double chainstitch sewing machine of the present invention, the tip end of the claw piece 14 is cut out leaving a part thereof, so that the distance from the needle holes 12, 13 to the cross rail 21 is shortened. Two
Since 1 can be closer to the needle hole than the conventional one,
The length of the needle thread connected to the looper 4 to the cross rail 21 becomes short. In other words, since the length of the needle thread in the free state becomes short, in the example shown in FIGS. 2 and 6, the needles 5 and 6 descend and the looper 4 reaches the left dead center and turns over, and moves rightward. When moving in front of the needle, the right needle thread N ₁ engaged with the looper 4
The amount of movement of the thread to the right along with the looper is reduced, and the thread tension regulator is switched to form an empty ring to increase the tension of the lower thread N ₃ and decrease the tension of the right needle thread N _1. On the contrary, the right needle thread N ₁ connected to the looper 4 is converged toward the left needle thread N ₂ side to form a bundled empty ring 8. After that, the air ring 8 passes through the guide groove 22 of the horizontal bar 21, and the rear feed dog 18 for pulling out the air ring,
It is clamped by 19 and the presser foot and pulled out rearward. At this time, since tension acts on each needle thread between the looper 4 and the cross rail 21, the left needle thread is moved slightly to the right as shown in the figure. It will be pulled out.

The reason why the protrusion 14a is left on a part of the tip of the claw is as follows. That is, in FIG. 6, the right protruding portion 1
Without 4a, the right needle thread N ₁ connected to the looper 4 when the needle is raised
Is lifted on the needle plate from the slit 15 near the right corner of the claw piece 14, but when it descends next, it will descend diagonally across the right needle hole 12 to the guide groove 22 on the upper surface of the claw piece 14. As a result, the needle thread tension is increased by catching on the tip of the claw piece 14 or thread breakage occurs.
On the other hand, when the protrusion 14a is located on the right side of the tip of the nail, the right needle thread N ₁ is blocked by the protrusion 14a and cannot be lifted up on the needle plate. Therefore, when the needle descends, the right needle thread N ₁ is caught by the nail piece. The needle thread tension does not rise and thread breakage does not occur. Since the guide groove of the left needle thread is on the left side, even when the needle thread is lifted up on the needle plate when the needle is raised, the left needle thread does not drop below the nail piece from the left corner of the nail piece and is not caught by the tip of the nail piece when the needle descends.

Further, the loop support 9 is provided on the needle receiver,
For the following reasons. That is, as shown in FIGS. 2 and 3, after the looper 4 moves to the left and scoops the right needle thread loop that is formed when the needle rises, when scooping the left needle thread loop, The continuous left needle thread loop tries to fall to the right because the empty ring is slightly "right" of the needle as described above. This is supported by the loop support 9 from the right side to prevent the loop from falling down, so that the looper 4 reliably scoops the left needle thread loop.

In the double chainstitch sewing machine according to the present invention,
The rear feed dog for pulling out the empty ring and the feed dog hole in which the feed dog is arranged are preferably formed in a step shape corresponding to the shape of the slit 15 on the front side in the cloth feed direction, and are separated in the front and rear. It is desirable to provide them individually.

[0011]

[0012]

In the above-described double chain stitch sewing machine, as a device for switching the tension of the thread tension regulator between ground stitching and forming an empty loop, for example, a manual operating member such as a foot pedal,
It is also possible to use a mechanism for activating the thread slackening member that loosens the tension of the thread tension regulator by the movement of the member, but it is preferable to use a sensor for cloth detection installed in the stitch forming area such as a needle plate, What is used is an actuating mechanism that actuates a thread loosening member that loosens the tension of the thread tension regulator depending on the presence or absence of cloth detection by the sensor. In the case of the former, the switching of the tension at the time of ground stitching and at the time of forming the empty ring is manually performed, whereas in the latter case, it is automatically performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a two-needle, double chainstitch sewing machine according to the present invention. Two rows of thread tension devices A ₁ and A _{2 are shown.}
In the thread tension device A, the A ₁ row is adjusted for ground stitching, and the A ₂ row is adjusted for forming an empty ring. The tension is switched so that the row becomes inactive, and when the empty ring is formed, the right needle thread N
The tension of ₁ is weakened and the tension of the lower thread (looper thread) N ₃ is strengthened. The above-mentioned tension switching is performed by a sensor (not shown) provided near the stitch forming area, for example, the needle hole of the needle plate. It is automatically performed depending on the presence or absence of cloth detection. That is, when the sensor does not detect the cloth after the cloth is sewn and an empty ring is formed, the tension is switched as described above.

The bobbin thread N ₃ directed from the thread tension device A toward the bobbin thread reel 1 is engaged with a thread take-up spring 2 formed of a torsion coil spring arranged on the bobbin thread reel device 1 side, and then the bobbin thread reel 1 and It passes through the lower thread guide 3 and the looper 4,
Left and right hands 5, 6 that move up and down, and looper 4 that swings left and right
By cooperation of, thereby forming a double chain stitch of two needle three thread between the left needle thread N ₂ of the right needle thread N ₁ and the left needle 6 of the right needle 5. During formation of the seam, the bobbin thread reeling device 1 reels in the bobbin thread from the thread tension device side, and pulls back the bobbin thread N ₃ which is loosened as the looper 4 moves to the right and tightens the thread while the looper 4 moves to the left. Performs the function of supplying the amount of thread required for seam formation,
The thread take-up spring 2 bends to bend the bobbin thread N ₃ when the thread tension of the thread is small, while the thread take-up spring 2 is raised when the thread tension is switched so that the bobbin thread N ₃ passes straight. When the bobbin thread reeling device 1 finishes pulling back the bobbin thread N ₃ , the bobbin thread to be relaxed is pulled back to the thread tension device side, and the right needle thread N ₁ kept at a low tension is left by the left needle. It is arranged so as to be brought closer to the yarn N ₂ side.

2 and 3, the needle receiver 7 that swings together with the looper 4 and engages with the tips of the needles 5 and 6 when the needle 5 rises from the bottom dead center to perform a needle guiding action. As shown
When the needle rises from the bottom dead center, the needle thread loop of the left needle 6 is supported from the right side, and it is prevented that the needle thread loop is pulled by the empty ring 8 and tries to fall to the right side, so that the looper 4 can be securely held. the needle thread loop so as to scoop, loop support 9 looper 4 and the needle 5,
It is attached so that it does not interfere with 6.

FIG. 4 shows a needle plate 11 used in the sewing machine.
The claw piece 14 formed in the cloth feeding direction from the needle holes 12 and 13 is cut away while leaving a part on the right side as a projecting portion 14a, and the length thereof is as shown in FIG. It is shorter than the claw piece 14 'and surrounds the claw piece 14 so that the needle hole 1
The tip of the slit 15 reaching 2 and 13 has a step shape. Two feed dog holes 16 and 17 divided by a reinforcing horizontal bar 23 are formed in the back and forth, and rear feed dogs 18 and 19 for pulling out the air ring are arranged in the front and rear.
The front feed dog hole 16 and the rear feed dog 18 are formed in a step shape so that the front side is aligned with the slit 15, and the slit 1
Guide groove 22 to reach the feed Haana 16 from the slit 15 in the refracted leftward from the center of the upper surface of the rung 21 of between 5 and feed dog hole 16 is formed (see FIG. 2).

FIG. 6 shows that when the tension of the right needle thread N ₁ is weakened and the tension of the lower thread N ₃ is increased by the thread tension device A, the looper 4 moves from the left dead center to the right. The right needle thread N connected to the looper 4 is shown as it moves.
₁ is on the left side and left needle thread N _{2 is} slightly closer to the right side,
It shows a state in which it is tightened when passing through the left dead center, becomes a grouped empty ring 8 through a guide groove 22, is sandwiched by the rear feed teeth 18 and 19 and the presser foot 20 and is pulled out rearward. . In the figure, W indicates the cloth after the end of the sewing in which the empty ring 8 is connected.

FIG. 7 shows a needle plate 24 used in a three-needle double chain stitch sewing machine. The left claw piece 25 is short, and the right claw piece 26 is a left half with a protruding portion 27 left. Shorten and cross rail 2
Reference numeral 8 corresponds to the claw pieces 25 and 26, and has a bent shape in which the left side is close to the needle hole 29, and a guide groove 30 for guiding an air ring is provided on the left side thereof.

[0020]

The present invention is constructed as described above and has the following effects. According to the double chainstitch sewing machine of claim 1, by making the claw piece shorter than the conventional one,
The needle thread hanging on the looper is less likely to move with the movement of the looper, and the tension switching device increases the tension of the lower thread and reduces the tension of one of the needle threads to reduce the left and right needle threads. Will be focused and become an integrated empty ring,
The bundled empty ring should be pulled out through the guide groove of the cross rail and held by the rear feed dog with the presser foot, and the needle receiver should be provided with a loop support to support the needle thread loop from the side. The hollow loop is reliably formed and pulled out because the hollow loop is surely formed by the scooping of the thread loop.

If a thread take-up spring is provided so as to absorb the looseness of the bobbin thread when the bobbin thread retractor has finished pulling back the bobbin thread, a low tension can be maintained. The needle thread present is closer to the needle thread having a higher tension and is more easily converged, so that it becomes a tight hollow ring and is easily pulled out.

[Brief description of drawings]

FIG. 1 is a perspective view of a two-needle double chain stitch sewing machine.

FIG. 2 is a perspective view of a seam forming area when forming an empty ring.

FIG. 3 is a front view of the same.

FIG. 4 is a plan view of a needle plate.

FIG. 5 is a plan view of a conventional needle plate having a claw piece.

FIG. 6 is a plan view of a needle plate when forming an empty ring.

FIG. 7 is a plan view of a needle plate for three needles.

[Explanation of symbols]

1 ... bobbin thread reel 2 ... thread take-up spring 4 ... looper 5, 6 ... needle 7 ... needle receiver 8 ... empty ring 9 ... loop support 11, 24 ...
.Needle plates 12, 13, 29 ... Needle holes 14, 14 ',
25, 26 ... Claw pieces 14a, 27 ... Projection portion 15 ... Slit 16, 17 ... Feed dog hole 18, 19 ...
· Rear feed dogs 21, 23, 28 ... Horizontal crosspieces 22, 30 ...
· Guide groove A ··· thread tension apparatus N ₁ ··· the right needle thread N ₂ ··· left needle thread N ₃ ··· under yarn W ··· cloth

Continuation of front page (56) Reference JP-A-3-23887 (JP, A) JP-A-5-300991 (JP, A) JP-A-5-237275 (JP, A) JP-A-49-22232 (JP , A) JP 55-138494 (JP, A) JP 4-34062 (JP, A) Actual opening 1-138377 (JP, U) Actual opening 1-101497 (JP, U) Actual opening 60-176789 (JP, U) Actual Kaihei 5-88480 (JP, U) Japanese Patent Publication 57-58191 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) D05B 1/10 D05B 63/00-65/06 D05B 73/12

Claims (4)

(57) [Claims] 1. A multi-needle forming a double chain stitch with a plurality of needles that move up and down in a direction orthogonal to the cloth feed direction and one looper that swings in the direction in which the needles are arranged below the needle plate. In the double chain stitch sewing machine, the needle receiver (7) swings in conjunction with the looper (4) and engages with the needle tip when the needle is raised to perform a needle guiding action.
A loop support (9) which is provided on the needle (6) and laterally supports a needle thread loop formed on the needle (6), a device for switching the tension of the thread tension adjuster for ground stitching or forming an empty ring, and a needle plate (11). ),
(24) is provided, and the needle plates (11) and (24) are formed in the cloth feeding direction and surrounded by the slit (15), and the protruding portions (14a) and (27 ), The other notched claw pieces (14), (26), and needle holes (12), (13) formed at the slit ends on both sides of the claw pieces (14), (26), respectively.
(29) and rear feed dogs (18) and (19) formed behind the slit (15) in the cloth feed direction for the empty ring drawing out, and the feed dog holes (16) and (17) and the above Guide rails (22) for guiding the air ring, which are formed on the upper surfaces of the horizontal rails (21) and (28) between the slit (15) and the feed dog hole (16) from the center to the other side,
A double chainstitch sewing machine having (30). 2. The rear feed dog for pulling out the empty ring and the feed dog hole in which the feed dog is arranged are formed in a step shape corresponding to the slit shape on the front side in the cloth feed direction. Double chain stitch sewing machine. 3. The double chain stitch sewing machine according to claim 1, wherein the rear feed dog for pulling out the empty ring and the feed dog hole in which the feed dog is arranged are separately provided in front and back. 4. The double chain stitch sewing machine according to claim 1, wherein a thread take-up spring for the bobbin thread is provided between the thread tension device and the bobbin thread reeling device.