JPH08229275A - Device for preventing skip stitch of sewing start end in sewing machine - Google Patents

Abstract

PURPOSE: To prevent the generation of a skip stitch by providing a sewing machine with a device for moving the thread end of needle thread hung from a needle between a cloth presser and a needle plate from a rear part to a front side, installing a thread end holder in front of a needle passing hole at the lower surface of the cloth presser and thereby preventing the slackening of the thread at a sewing start end. CONSTITUTION: An air ejecting pipe 9 as a thread end moving device whose one end is connected through a valve 8 to a high pressure air source 7 is disposed in the rear part and on the slightly left side of a sewing machine needle 1 and an ejecting port 10 formed on the other end of the air ejecting pipe 9 is opened towards the slightly right side in front of the sewing machine at the upper surface of the needle plate 2. In the meantime, an intake pipe 13 as the thread end holder whose air sucking port 12 is opened in front of the needle passing hole 11 at the lower surface of the cloth presser 6 is attached and the intake pipe 13 is connected to an air evacuating device 16 through a flexible connecting pipe 14 and the valve. Then, the thread end of the needle thread cut and hung from the needle 1 when sewing is ended is sent from the needle passing hole 11 of the cloth presser 6 to the front side by ejected air from the ejecting port 10 and held by air sucking force at the sucking port 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewing machine needle, a needle plate, and a feed dog which moves through the hole of the needle plate to move back and forth and up and down.
The present invention relates to a stitch skip prevention device at a sewing start end in a sewing machine provided with a presser foot provided so as to face a feed dog.

[0002]

2. Description of the Related Art When starting a sewing operation using a sewing machine,
Since the thread end of the sewing thread cut at the end of sewing in the previous sewing operation is in a loose state, especially in a double chain stitch sewing machine, the loop of the needle thread that forms the first stitch Becomes too large and falls sideways, and during the progress of stitching for 2 or 3 stitches, normal stitches are not obtained and stitch skipping easily occurs, resulting in defective sewing products.

[0003]

In order to eliminate the slack of the thread at the beginning of sewing, it has been hitherto made, for example, in Japanese Patent Laid-Open No. 3-921.
Various types of yarn end holding devices such as No. 92 and Jitsukaihei 2-4577 are used. However, since these thread end holding devices hold the thread ends above and to the side of the presser foot of the sewing machine, the thread tension increases as the needle drops when sewing is started, and the thread end is held. If the release timing does not match, there is a problem that abnormal tension is applied to the needle thread to cause puckering on the cloth, or the thread is loosened and skipped.

Accordingly, an object of the present invention is to provide an apparatus which, in sewing work by a sewing machine, prevents loosening of the thread at the sewing start end to prevent the occurrence of stitch skipping, and can obtain a sewn product without wrinkles at the start of sewing. To provide.

[0005]

In order to solve the above-mentioned problems, a stitch skipping preventive device for a sewing start end in a sewing machine of the present invention is a sewing machine needle, a needle plate and a hole in the needle plate. In a sewing machine having a feed dog that moves in a horizontal direction and a presser foot provided opposite to the feed dog, the needle end of the needle thread that hangs down from the needle between the presser foot and the needle plate is moved to the front side of the needle. The present invention is characterized in that the device and the yarn end of the needle thread in a state of being laid along the lower surface of the cloth presser from the needle passage hole of the cloth presser are held by a holding device attached to the cloth presser.

One example of using an air control mechanism for the means is to provide a fumarolic pipe connected to a high-pressure air supply source behind the sewing machine needle so that its discharge port is opened toward the front of the needle plate upper surface. An intake pipe having an air suction port opened is provided in front of the needle passage hole on the lower surface of the work clamp, an air pressure reducing device is connected to the intake pipe, and the yarn end of the yarn connected to the needle is ejected from the discharge port. Transfer to the air suction port by air flow,
It is configured to be held in the suction tube by its suction action.

Further, one example of combining a mechanical mechanism is to provide a needle thread wiping rod so as to reciprocate back and forth between the cloth presser and the needle plate, and to provide air to the front side of the needle passage hole on the lower surface of the cloth presser. An air intake pipe with an open suction port is provided, an air pressure reducing device is connected to the air intake pipe, and the needle thread wiper rod is moved from the rear to the front of the cloth presser so that the yarn end of the yarn connected below the needle is moved. It is transferred to the air suction port and held by the suction action in the suction pipe. Further, the yarn end holding device may be a mechanical mechanism.

When the sewing machine equipped with a needle thread cutting device is used in the former example, a control is performed in which air is ejected from the fusogenic pipe in conjunction with the thread cutting operation and suction is performed in the intake pipe. It is desirable to provide a device, and also to provide a control device for performing the ejection action from the fumarole pipe and the suction action in the intake pipe in conjunction with the lifting and lowering of the presser foot, or in conjunction with the lowering of the presser foot. A control device for stopping the suction action in the intake pipe can be provided.

[0009]

[Function] After sewing the cloth, cutting the thread continuing to the rear end of the cloth, raising the cloth presser to remove the cloth, and then hanging down the needle between the cloth presser and the needle plate by the thread end moving device. The thread is moved to the front side of the needle, and the thread end holding device holds the thread end of the needle thread in a state of being laid along the lower surface of the cloth presser from the needle passage hole of the cloth presser. Next, supply the cloth to be sewn next onto the needle plate,
When the presser foot is lowered onto the needle plate, the needle thread held along the lower surface of the presser foot is pinched between the needle passage hole on the upper surface of the cloth and the lower surface of the presser foot and the thread end holding device. The sewing machine is fixed in the same way as when the sewing machine was stopped during sewing.
When the sewing machine is started, the needle thread forms a stable needle thread loop as the cloth advances, and it is possible to prevent the occurrence of skipped stitches that tend to occur at the beginning of sewing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the shapes, structures and arrangements shown in the drawings and the description thereof. 1 and 2, the sewing machine needle 1 holds a needle thread NT, moves up and down through a needle drop hole 3 of a needle plate 2 as the sewing machine is driven, and is provided below the needle plate 2 and is not shown. A seam is formed in cooperation with a looper that holds a looper thread. On the other hand, feed dog 4
Moves forward and backward and up and down through the feed dog hole 5 provided in the needle plate 2, and cooperates with the cloth presser 6 provided facing the feed dog 4 to feed the cloth W supplied onto the needle plate. Send from the front of the falling hole 3 to the rear.

In this sewing machine, a high-pressure air source 7 is connected through a valve 8 at one end, and a fumarole tube 9 as a yarn end moving device is connected.
Is provided on the rear side of the sewing machine needle 1 (on the left side in the figure) and slightly on the left side, and the discharge port 10 provided on the other end is opened toward the front side (on the right side in the figure) of the sewing machine on the upper surface of the needle plate 2 toward the right side. I am letting you. On the other hand, the needle passing hole 11 on the lower surface of the presser foot 6
An intake pipe 13 serving as a yarn end holding device having an air suction port 12 opened to the front is provided, and the intake pipe 13 is connected to an air pressure reducing device 16 via a flexible connecting pipe 14 and a valve (not shown). are doing. The valves 8 and the like can be manually operated, but are controlled by a drive control mechanism of a sewing machine (not shown). Further, the drive control mechanism of this sewing machine can control the valve in association with the operations of the needle thread cutting device and the cloth presser lifting device.

In the apparatus of this embodiment, after sewing the cloth, the needle thread NT connected to the rear end of the cloth is cut, the cloth presser 6 is lifted to remove the cloth, and then the fumarole pipe provided behind the sewing machine needle 1. When air is ejected from the discharge port 10 of 9 toward the front arrow A direction on the upper surface of the needle plate 2, the thread cutting end TE which is continuous with the lower part of the needle 1 is arranged along the lower surface of the presser foot 6 in the vicinity of the air suction port 12. Be sprayed on. The yarn end TE is sucked and held in the intake pipe 13 by the suction action of the air pressure reducing device 16 connected to the air suction port 12 via the connecting pipe 14 and the valve 15.

Next, when the cloth W to be sewn next is supplied onto the needle plate 2 and the cloth presser 6 is lowered onto the needle plate, the needle thread whose thread end TE is held in the intake pipe is The part TM closer to the needle is sandwiched between the upper surface of the cloth and the lower surface 6a of the cloth presser between the needle hole 11 of the cloth presser and the air suction port 12. In this way, the state in which the thread end is held between the lower surface of the presser foot and the cloth at the start of sewing is the same as the state of the thread during normal sewing, so that thread slack or pulling occurs. Never.

Since the yarn end TE is held only in the suction pipe 13 by the suction action and is not mechanically firmly held, the yarn tension is strong even if the suction action is not stopped at the start of sewing. In this case, it is gradually pulled back from the holding portion, and wrinkles due to abnormal yarn tension do not occur.

[0015]

As described above, according to the present invention, in the sewing operation by the sewing machine, the thread end of the needle thread that is cut off at the end of sewing and hangs down from the needle is also moved from the needle passage hole of the presser foot to the front side by the moving device. The sewing machine holds the sewing machine along the lower surface of the presser foot by the holding device, and when the sewing is started next time, the thread end of the needle thread is sandwiched between the upper surface of the cloth and the lower surface of the presser foot, and the sewing machine is stopped during sewing. When the sewing machine is started, the needle thread forms a stable needle thread loop as the cloth advances, so that the occurrence of skipped stitches that tends to occur at the start of sewing can be prevented. Further, the work efficiency can be improved by controlling the yarn end moving device and the holding device in association with the sewing machine drive device, the thread trimming device, the cloth presser lifting device, and the like.

[Brief description of drawings]

FIG. 1 is a side view of a main part of a sewing machine adopting an embodiment of the present invention,

FIG. 2 is likewise a side view showing the action of the sewing machine, 1:
Sewing machine needle, 2: Needle plate, 3: Needle drop hole, 4: Feed dog, 6: Presser foot, 7: High pressure air source 9: Fume tube (thread end moving device), 10: Discharge port, 11: Needle passage hole , 1
2: Air suction port, 13: Intake pipe (thread end holding device),
14: Connection pipe, 16: Air pressure reducing device

Claims (6)

[Claims] 1. A sewing machine comprising a sewing machine needle, a needle plate, a feed dog that moves back and forth and up and down through a hole of the needle plate, and a cloth presser provided to face the feed dog. A device for moving the thread end of the needle thread hanging from the needle between the needle plates from the rear side to the front side is provided, and a thread end holding device is provided in front of the needle passage hole on the lower surface of the work clamp to pass the needle thread. A stitch skipping preventive device for a sewing start end in a sewing machine, wherein the device is held along a lower surface of a presser foot through a hole and is held by the thread end holding device. 2. A high-pressure air supply for a sewing machine comprising a sewing machine needle, a needle plate, a feed dog penetrating through a hole of the needle plate and moving back and forth and up and down, and a presser foot provided opposite to the feed dog. An air intake pipe connected to the source is provided behind the sewing machine needle so that its discharge port is opened toward the front of the needle plate upper surface, and the air suction port is opened before the needle passage hole on the lower surface of the work clamp. The air pressure reducing device is connected to the intake pipe,
The skipping of the sewing start end in the sewing machine is characterized in that the yarn end of the yarn connected to the needle is transferred to the air suction port by the air flow ejected from the discharge port and held by the suction action in the suction pipe. Prevention device. 3. The sewing machine according to claim 2, further comprising a needle thread cutting device, and a control device for interlocking with the thread cutting operation to eject air from the fumarolic pipe and perform suction action on the intake pipe. A stitch skip prevention device at the sewing start end of the sewing machine. 4. A stitch skipping preventive device for a sewing start end of a sewing machine according to claim 2, further comprising a control device for interlocking with lifting and lowering of said cloth presser to cause ejection from said fumarole pipe and suction action on said intake pipe. . 5. A stitch skipping preventive device for a sewing start end of a sewing machine according to claim 2, wherein a space between the needle passage hole and the air suction port on the lower surface of the presser foot is formed in the same plane as the main part of the lower surface of the presser foot. . 6. A sewing machine including a sewing machine needle, a needle plate, a feed dog that moves back and forth and up and down through a hole of the needle plate, and a cloth presser provided so as to face the feed dog. A needle thread wiping rod is provided so as to reciprocate back and forth between the needle plates, and an intake pipe with an air suction port opened is provided in front of the needle passage hole on the lower surface of the presser foot, and an air pressure reducing device is installed in the intake pipe. By connecting and moving the needle thread wiping rod from the rear side to the front side of the cloth presser, the yarn end of the thread continuing under the needle is transferred to the air suction port and held by the suction action in the suction tube. A stitch skip prevention device at the sewing start end of a sewing machine.