JPH0430879B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention has a plurality of needles arranged in parallel in a direction perpendicular to the cloth feeding direction, reciprocating along the cloth feeding direction,
The present invention relates to a thread cutting device for a multi-row double chain stitch sewing machine, which includes a plurality of loopers that cooperate with each needle to form a double chain stitch.

Conventional technology A multi-row double chainstitch sewing machine that is used exclusively for sewing bands or tapes onto fabrics, such as when sewing elastic bands around the waist of jogging pants, has a looper that runs in the fabric feed direction. There are two types in which the looper reciprocates vertically along the cloth and multiple needles are lined up in a direction perpendicular to the cloth feed, and a type in which the looper reciprocates horizontally and the needles are arranged diagonally in the cloth feed direction. There is one. With the latter type, the stitches formed by each needle at the same time shift in the feed direction, but with the former type, there is no misalignment, so the advantage is that the overlap stitches at the end of the stitch can be beautifully finished. However, in conventional sewing machines of this type, cutting the needle thread and looper thread after sewing was completed manually using scissors.

It has also been proposed to cut threads by installing a thread cutting device consisting of a movable blade and a fixed blade that cuts threads in cooperation with the movable blade (Special Publication No. 61-27209
issue).

Problems to be Solved by the Invention The present invention attempts to perform thread cutting by providing a thread cutting device, but when installing the thread cutting device, care should be taken so that it does not interfere with the movement of the looper, feed dog, etc. In addition, it is desirable that the length of the remaining yarn be short enough to prevent it from falling out, and that there be no difference in the length of the remaining yarn extending from each needle or looper.

The present invention improves the conventional thread cutting device,
It is an object of the present invention to provide a thread cutting device installed in the sewing machine described above that satisfies the above-mentioned requirements.

Means for Solving the Problems The thread cutting device of the present invention has a plurality of needles arranged in parallel in a direction perpendicular to the cloth feed direction, and reciprocates along the cloth feed direction, and cooperates with each needle to form a plurality of rows of double needles. In a multi-row double chain stitch sewing machine consisting of a plurality of loopers that form chain stitches, a plurality of hook-shaped hooks are installed corresponding to each looper so that they can move back and forth between the upper and side of the loopers. A knife, a hook-shaped knife drive means that faces the looper, bends or bends near the looper, and advances or retreats along a path along the looper; A receiving knife is biased in the forward direction by an engaging means that engages with the receiving knife when the knife is retracted from the looper and causes the receiving knife to retreat against the action of the spring; and a release means that engages with the latch lever to release the locking of the receiving knife by the latch lever, and when the hook-shaped knife moves back, the thread is cut in cooperation with the receiving knife activated by the retreating of the hook-like knife. It is characterized by:

The route that the hook-shaped knife follows is like a J or L shape, and the hook-shaped knife drive means that moves the hook-shaped knife back and forth along these routes uses a link mechanism, for example, a parallel link and a mechanism that moves the link back and forth. The actuating mechanism moves the parallel links together toward the looper and moves them forward, and after moving forward a certain amount, one of the opposing links is rotated relative to the other link that stops moving. Those using a link mechanism that allows the hook-shaped scalpel to draw a J-shaped trajectory or those that use a cam mechanism, for example, as shown in the following example, a J- to L-shaped For example, a cam mechanism is used in which a pair of guide holes is provided, a guide pin is fitted into each hole, and the movable plate is moved in a J or L shape by an operating mechanism such as an air cylinder connected to the movable plate. can be mentioned.

Example Figure 1 shows a multi-row double chainstitch sewing machine.
Inside the bed 1, a plurality of loopers 3 are arranged in parallel, which reciprocate back and forth along the cloth feeding direction and cooperate with the needle 2 to form a double chainstitch, and the whole is indicated by the reference numeral 4 on the side of the looper. A thread cutting device is provided.

As shown in detail in FIGS. 2 to 4, the thread cutting device 4 consists of a guide path 5a extending in the left-right direction toward the looper 3 and a guide path 5b extending in the front-rear direction along the looper 3. A movable plate 6 has a pair of L-shaped guide holes 5 formed therein, a pair of fixed guide pins 7 that are slidably fitted into each guide hole 5 of the movable plate 6, and a movable plate 6 that passes through a long hole 8. A thin plate-like mounting plate 11 is attached to the movable plate 6 so that its position can be adjusted in the left and right direction by a set screw 9 fixed to the plate, and a thin plate-shaped mounting plate 11 is provided with the same number of loopers as the loopers 3 and the spacing between the loopers. Hook-shaped scalpels 12 installed in parallel at the same intervals
an air cylinder 15 which is diagonally connected to the movable plate 6 and whose piston rod 14 advances and retreats with a motion component along the guide path 5a and a motion component along the guide path 5b; A receiving knife 17 is slidably supported by a rod 16 extending in the direction, and has a cutting edge formed at its tip, a leaf spring (not shown) attached to the lower side of the receiving knife 17, and a plate spring (not shown) protruding from the side of the receiving knife 17. A guide member 211 has a guide groove 19 into which the protrusion 18 fits, and guides the movement of the receiving knife 17 along the rod 16 to stop the rotation of the receiving knife 17.
a coil spring 22 that urges the sewing machine to the left in the figure; a claw lever 24 that is pivotally supported on the sewing machine frame and that removably engages with the protrusion 23 of the receiving knife 17 to lock the receiving knife 17; A helical spring 25 urges the claw lever 24 to rotate counterclockwise in the figure, a stopper pin 26 restricts the counterclockwise movement of the claw lever 24, and a stopper pin 26 that is pivoted on the same axis as the claw lever 24 at the bent part. Bell crank-shaped release lever 28
a helical spring 31 that is hooked on the claw lever 24 and the release lever 28 to open both levers and engage one side of the release lever 28 with the tongue piece 29 that projects upward from the claw lever 24; and a movable plate 6. A protruding part 33 is formed protruding from the side of the lever 28 and engages with the stepped part 32 of the receiving knife 17, and a protruding part 33 is provided to protrude upward from the movable plate 6 and engages with the other side part of the release lever 28 to release the lever 2.
8 and a pin 35 for rotational operation.

Thread cutting by this device is performed as follows.

The thread cutting device 4 is always in the state shown in FIG. 2, and when cutting the thread, from this state the switching valve (not shown) of the air cylinder 15 is switched,
The piston rod 14 is made to protrude. The movable plate 6 is guided by the guide pin 7 due to the motion component along the guide path 5a and moves to the left in the figure. Guide route 5a
By the time the right end reaches the guide pin 7, the pin 35 engages with the release lever 28, and the lever 28 is rotated counterclockwise in the figure against the action of the helical spring 31. When the pin 35 comes off the tip of the release lever,
The release lever 28 rotates clockwise in the figure and returns to its original position. When the right end of the guide path 5a reaches the guide pin 7, the pin 35 is therefore located on the left side of the release lever 28 (see FIG. 3). At the time when the right end of the guide path 5a engages with the guide pin 7, each hook-shaped knife 12 also closes to each corresponding looper 3.
is located behind. When the piston rod 14 further protrudes from this, the movable plate 6 is guided by the guide pin 7 and pushed downward in the figure by its motion component along the guide path 5b. As a result, each hook-shaped knife 12 protrudes from the receiving knife 17 and moves forward along the looper 3, passing through the needle thread loop hung on each looper 3. 3 shows a state in which the rear end of the guide path 5b is engaged with the guide pin 7 and the hook-shaped knife 12 has reached the forward end, and FIG. 6 shows the hook-shaped knife 12
The state when the thread has passed through the needle thread loop 41 is shown. In the figure, 37 is a needle hole formed in the throat plate 38 (see FIG. 1), and 40 is a retainer. This retainer moves perpendicular to the direction of movement of the looper. In other words, when the looper advances toward the front, it engages the looper thread connected to the seam from the left and moves to the right, pulling the looper thread away from the looper and widening the gap so that the needle can reliably pass through the gap. .

As described above, the hook-shaped knife 12 moves to the left facing the looper during thread cutting, and after reaching behind the looper, moves forward along the looper in an L-shaped trajectory. FIG. 5 shows the trajectories of these hook-shaped scalpels.

Immediately after the hook-shaped knife 12 reaches the forward end, the switching valve of the air cylinder 15 is switched again and the piston rod 14 begins to retract. Accordingly, the movable plate 6 moves in the opposite direction to that described above, and the hook-shaped knife 12 moves back along an L-shaped trajectory. That is, first, the movable plate 6 is guided by the guide pin 7,
The pin 7 retreats until it reaches the front end of the guide path 5b (the right end of the guide path 5a), and the hook-shaped knife 12 retreats on the looper. On the way, the needle thread loop 41 and the looper thread 42 that are hung on the looper 3 are captured and once pulled rearward. Then, as the movable plate 6 moves to the right, it is pulled to the right. When the movable plate 6 moves an appropriate amount to the right, the pin 35 moves to the release lever 28 as shown in FIG.
The lever is pushed and rotated clockwise in the figure to push the tongue piece 29, and the claw lever 24 is rotated in the same direction to release the engagement with the protrusion 23 of the receiving knife 17. The receiving knife 17 released from the lock by the pawl lever 24 flies out to the left in the figure by the action of the coil spring 22, and each hook-shaped knife 1 is placed between the cutting blade at the tip and a leaf spring (not shown) pressed against the lower surface of the receiving knife 17.
2 and cut the needle thread 41 and looper thread 42 captured by each hook-shaped knife 12. Note that the receiving knife 17 is stopped from moving to the left by the stepped portion 32 engaging with the protruding portion 33 of the movable plate 6 that moves to the right. In FIG. 4, the stepped portion 32 is replaced by the protruding portion 33.
This shows the state at the time when the thread has been engaged and thread trimming has been completed. When the movable plate 6 tightens and moves to the right,
Accordingly, the receiving knife 17 is also pushed back to the right by the protrusion 33 against the action of the coil spring 22.
On the way, the pin 35 moves backward as it comes off from the release lever 28, and the receiving knife 17 is engaged with the claw lever 24, which has been engaged with the stopper pin 26 and returned to the state shown in FIGS. 2 and 3. The protrusion 23 is engaged. The engaging portion of the tip of the receiving knife with the protrusion 23 is an inclined surface 24a as shown in the figure, so as the protrusion 23 moves to the right in the figure, the claw lever 24 is moved by the action of the helical spring 25. I am pushed up against it. Immediately after the protrusion 23 passes, it moves back, engages with the protrusion 23, locks the fixed knife, and returns to the state shown in FIG. 2.

Effects of the Invention As described above, the present invention is a multi-row double chain stitch sewing machine in which the loopers are lined up front and back along the cloth feeding direction, in which the thread cutting device is arranged on the side of the looper, and when cutting the thread, the hook-like knife is moved to the looper. The thread is cut by the thread cutting device, which moves forward and backward along a path along the looper, and cuts the thread in cooperation with a receiving knife that moves in the opposite direction when retracting. The thread cutting device is located on the side of the looper, so it can be installed not only on sewing machines with a regular-sized bed but also on sewing machines with a cylindrical bed. Since the thread is cut in cooperation with the hook-shaped scalpel on the way back, the cut end of the thread can be cut to an appropriate length without being too long or too short. Since the hook-shaped knives move in opposite directions, the time lag between the hook-shaped knives when cutting the thread is reduced, making it possible to cut the thread instantaneously, and ensuring that the remaining thread lengths extending from each needle and looper are the same. The receiving knife is moved forward by the spring, the receiving knife is moved backward by the hook-shaped knife, the receiving knife is held in the retreated position and restrained by the latch lever, and the receiving knife is released by the latch lever by the hook-shaped knife. Each is performed by an integrally provided release means, and the movement of the receiving knife is performed by a spring and the movement of a hook-shaped knife. This has the advantage of simplifying the structure.

[Brief explanation of drawings]

Figure 1 is a perspective view of a multi-row double chainstitch sewing machine, Figure 2
The figure is a plan view of the thread cutting device installed in the bed of the sewing machine in its normal state, FIG. 3 is a plan view when the hook-shaped knife reaches the forward end, and FIG. 4 is a plan view when thread cutting is completed. FIG. 5 is a diagram showing the trajectory of the hook-shaped knife, and FIG. 6 is a perspective view showing the state when the hook-shaped knife passes through the needle thread loop. 1... Bed, 3... Looper, 4... Thread cutting device, 5
...Guide hole, 6...Movable plate, 7...Guide pin, 12...Hook-shaped knife, 15...Air cylinder, 17...Reception knife, 22...Coil spring, 24...Claw lever, 2
5, 31... Helical spring, 28... Release lever.

Claims (1)

[Claims] 1.Made of a plurality of needles arranged in parallel in a direction perpendicular to the cloth feeding direction and a plurality of loopers that reciprocate along the cloth feeding direction and cooperate with each needle to form multiple rows of double chain stitches. In this multi-row double chainstitch sewing machine, a plurality of hook-shaped knives are installed corresponding to each looper so as to be able to reciprocate between the upper side and the side of the looper, and the hook-shaped knife faces the looper. a hook-shaped knife driving means that bends or bends near the looper and advances or retreats along a path along the looper;
A receiving knife that is normally biased in the forward direction by a spring, a latch lever that removably locks onto the receiving knife in the retreated position and restrains the receiving knife in the retreating position, and a hook-shaped knife are provided integrally. an engaging means that engages with the receiving knife when the knife is retracted from the looper and causes the receiving knife to retreat against the action of a spring; and an engaging means that is provided integrally with the hook-shaped knife and that is provided integrally with the hook-shaped knife while the knife is being retreated from the looper. and a release means that engages with the latch lever and releases the locking of the receiving knife by the latch lever, so that when the hook-shaped knife moves back, the thread is cut in cooperation with the receiving knife that is activated by the retreating of the hook-like knife. A thread cutting device for a multi-row double chainstitch sewing machine, which is characterized by: