JPH0418553Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial field of application 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 along the feed direction. One type has a looper that reciprocates vertically and has multiple needles lined up in a direction perpendicular to the fabric feed, and the other type has a looper that reciprocates horizontally and the needles are arranged diagonally in the feeding direction. There is. 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, cutting the needle thread and looper thread after sewing has been done manually using scissors on conventional sewing machines of this type.

Problems that the invention aims to solve This invention aims to improve work efficiency by installing a thread cutting device in the sewing machine mentioned above, and using the thread cutting device to cut the thread that was previously done manually. However, when installing a thread cutting device, it is necessary to ensure that it does not interfere with the movement of the looper, feed dog, etc., and for space reasons, it is better to install it on the side of the looper rather than behind it. desired. In this case, special measures are required for the thread cutting device to ensure thread cutting for each looper.

The object of this invention is to provide a thread cutting device installed in the above-mentioned sewing machine that satisfies this requirement.

Means for Solving the Problem According to the present invention, therefore, the first link is provided with a first protrusion and is guided by a guide means to move forward or backward toward the looper, and the first link is disposed parallel to the link, and when moving backward, the first link is arranged parallel to the first link. a second link having a second protrusion that engages with the first protrusion; a pair of parallel links that connect the first and second links so that both links move parallel to each other; an actuation mechanism that moves the link back and forth; a spring that biases the first link so that when the second link moves forward toward the looper, the first link moves forward; and A thread trimming knife supported and moving parallel to the first and second links, a plurality of hook-shaped knives arranged in parallel on the thread trimming knife, and corresponding to each looper; A receiving knife has a cutting edge along the arrangement direction of the hook-shaped knife and cuts the thread in cooperation with each hook-shaped knife, and the first link, which moves forward as the second link moves forward, restricts the forward movement of the first link to a certain position. A thread cutting device is provided, which includes a stopper means, and in which each hook-shaped knife draws a substantially J-shaped trajectory due to the advancement of the second link and its corresponding rotation.

Here, the guide means includes a pair of elongated holes or elongated grooves formed in either one of the first link and the fixing member on the sewing machine frame, and a pair of elongated holes or elongated grooves that are attached to the other and are slidable in the elongated holes or elongated grooves, respectively. It consists of a pair of pins that fit together, a groove formed on one of the first link and the fixing member, and a protrusion or a protrusion formed on the other side and slidably fitted into the groove. Examples include a cylindrical body into which a part of the first link is slidably fitted.

An example of the actuation mechanism is one consisting of a cylinder or solenoid, and a linkage mechanism that connects the cylinder or solenoid to a second link.

The thread cutting knife table may be attached directly to the parallel link, or may be attached to an extended portion of one end of the parallel link. Further, a side protrusion can be provided on the parallel link or an extension thereof, and a thread cutting knife table can be attached to the first protrusion. By doing so, the movement locus of the thread trimming knife can be set to the optimum condition in relation to the installation space.

The receiving knife is fixed to the first link, or directly to the sewing machine frame near the first link, or to a mounting member attached to the sewing machine frame. In the case of the former, which is fixed to a link, the receiving knife moves forward and approaches the looper to cut the thread, making it possible to shorten the cut end of the thread. Although a plurality of receiving knives may be individually provided corresponding to the hook-shaped scalpels, they are preferably formed as a single unit.

Regarding the stopper means, for example, a protrusion may be formed on the first link so as to be engaged with a separately provided stopper, or a side end surface of the cylindrical body constituting the guide means may be used. , the protrusion may be engaged with this, and furthermore, an elongated hole or elongated groove and a pin constituting the guide means may be used. That is, one end of the elongated hole or elongated groove is used as a means for restricting the movement of the pin.

As the spring, a tension spring that connects the first and second links or a compression spring that biases the first link from the rear end is used.

Example In the figure, needles 1 are arranged in parallel in a direction perpendicular to the cloth feeding direction, and move back and forth in the bed 2 along the cloth feeding direction to form a double chain stitch in cooperation with the needle 1. A plurality of loopers 3 are arranged in parallel, and a thread cutting device, generally designated by reference numeral 4, is provided on the side of the looper.

The thread cutting device 4 has a base plate 5 fixed within the bed, as shown in detail in FIGS. 2 and 3.
A pair of elongated holes 6, 6 are bored in the longitudinal direction, and protrusions 7, 7 are formed on both sides, and guided by stepped screws 8, 8 fixed to the base plate 5 through each elongated hole 6, 6. and a link 9 that slides in the lateral (left and right) direction on the base plate;
The pin 1 is arranged parallel to the pin 1 and is attached to the one protrusion 7 when moving along the link 9 to the right in the figure.
The link 13 has a protruding piece 12 that engages with the link 13, and the link 13 has a bell crank shape, and one end is pivoted to the link 13, and a bent part 14b is pivoted to the link 9.
and a pair of parallel links 14 that form a parallelogram together with a part of 13, a tension spring 15 that connects both links 9 and 13 by hanging one end on the link 13 and the other end on the link 9, and a tension spring 15 with both ends parallel to each other. A thread trimming knife stand 16 is pivoted on the other end 14a projecting to the side of the link 14, a hook-shaped knife 17 is attached to the knife stand in the same number and at the same spacing as the loopers 3, and a hook-shaped knife 17 is fixed to the link 9 and attached to the hook. A receiving knife 18 that cuts the thread in cooperation with the shaped knife 17, a stopper 19 fixed to the base plate 5 and with which the protrusion 7 engages, an air cylinder 21, and the cylinder and the link 1.
3 and a link mechanism 22 that connects the two.

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 thread cutting is performed, the switching valve (not shown) of the air cylinder 21 is switched from this state, and the piston rod 23 is moved backward. As a result, the link 13 moves to the left in the figure via the link mechanism 22, and the link 9, which is connected by the tension spring 15, moves in conjunction with this movement and moves to the left in the figure together with the link 13 ( The same applies to the thread cutting knife table 16).
During the movement of the link 9, the protruding piece 7 engages with the stopper 19, stopping the movement of the link 9. However, as the link 13 moves further to the left, the parallel links 14, 14 move around the bent portion 14b as shown in the figure. It rotates counterclockwise, and the link 13 and the thread cutting knife table 16 rotate while keeping the link 9 in a parallel state. The tip of each knife then traces an arcuate trajectory to reach the top of the looper (see FIG. 3), and passes through the needle thread loop placed on each looper 3. That is, as shown in Fig. 4, the knife 17 moves in a J-shaped trajectory, that is, to the left, and then moves toward the front side of the sewing machine and follows a trajectory that is an asymptote with respect to the fabric feeding direction (the same direction as the looper movement). and reach their corresponding loopers. FIG. 5 shows the state when the hook-shaped knife 17 has passed through the needle thread loop 25. 26 in the diagram
is a needle hole formed in the throat plate 27 (see FIG. 1), and 29 is a retainer. This retainer moves perpendicular to the direction of movement of the looper. That is, when the looper advances toward the front side, it engages from the left with the looper thread connected to the seam, moves to the right, pulls the looper thread away from the looper, widens the gap, and ensures that the needle can be inserted through the gap.

Immediately after the hook-shaped knife reaches the forward end, the switching valve of the air cylinder 21 is switched again, and the piston rod 23 moves forward. As a result, each of the links moves backward by following the movement opposite to the above. That is, first, the link 13, the thread cutting knife table 16, and the hook-shaped knife 17 retreat in the same direction as the cloth feeding direction, and retreat to the right along a J-shaped trajectory. During this time, the hook-shaped scalpel 17 captures the needle thread loop 25 and the looper thread 30 that are hung on the looper 3, and cuts each thread in cooperation with the receiving knife 18 which pulls them and waits. The tension spring 15 is once stretched by the link 13 that continues to move to the left after the link 9 stops, but as the link 13 moves to the right, it contracts and returns to its original state. When the link 13 completes its rotation and moves further to the right, the protruding piece 12 of the link 13 engages with the pin 11 of the link 9, which moves the link 9 to the right, resulting in the state shown in FIG. to be restored.

In the illustrated device, the receiving knife 18 is installed parallel to the link 9, so that thread cutting is performed in the middle of the arc locus shown in FIG. Alternatively, it may be installed diagonally. In the former case, the lengths of the cut ends of each needle thread and looper thread are the same or almost the same, but in the latter case, the thread is cut near the base of the arcuate trajectory shown in Figure 4 or on the straight trajectory. The length of each piece will be slightly different.

Effects of the invention As described above, this invention is a thread cutting device for a multi-row double chainstitch sewing machine in which the needles are arranged in a direction perpendicular to the cloth feeding direction and the loopers are parallel to each other in the cloth feeding direction in correspondence with each needle. It is placed on the side of the looper, and in this type of sewing machine, conventional scissors are used,
Thread cutting, which used to be done by hand, can now be done using a thread trimming device, improving work efficiency and making it suitable not only for sewing machines with regular-sized beds, but also for sewing machines with cylindrical beds. Moreover, by making each hook-shaped knife movable in a J-shaped trajectory, it is possible to reliably cut the thread for each looper and to make the lengths of the thread cutting ends the same. It has the following effects.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a multi-row double chainstitch sewing machine equipped with a thread cutting device according to the present invention, Fig. 2 is a plan view of the thread cutting device in normal operation, and Fig. 3 is a perspective view of the thread cutting device during thread trimming. FIG. 4 is a plan view showing the locus of the hook-shaped scalpel, and FIG. 5 is a perspective view showing the state when the hook-shaped knife passes through the needle thread loop. 1... Needle, 2... Bed, 3... Lupa, 4...
... Thread cutting device, 9, 13... Link, 14... Parallel link, 16... Thread cutting knife stand, 17... Hook-shaped knife, 18... Receiving knife.

Claims (1)

[Claims for Utility Model Registration] (1) A plurality of needles arranged in parallel in a direction perpendicular to the cloth feeding direction, and a plurality of rows of double rings that reciprocate along the cloth feeding direction and cooperate with each needle. A multi-row double chainstitch sewing machine comprising a plurality of loopers forming a seam, the first link having a first protrusion and moving forward or backward toward the looper while being guided by a guide means; a second link that is arranged in parallel and has a second protrusion that engages with the first protrusion when retracting; and a pair that connects the first and second links so that both links move parallel to each other. a parallel link, an operating mechanism for moving the second link back and forth, and the first link is attached so that when the second link moves forward toward the looper, the first link moves forward in conjunction with this. a thread cutting knife supported by both of the parallel links and moving parallel to the first and second links; and a plurality of thread cutting knives arranged in parallel on the thread cutting knife in correspondence with each looper. a hook-shaped scalpel, a receiving knife that has a cutting edge along the arrangement direction of the hook-shaped knives and cuts the thread in cooperation with each hook-shaped knife, and a first knife that moves forward as the second link moves forward. a stopper means for restricting the forward movement of the second link to a fixed position, and each hook-shaped female draws a substantially J-shaped trajectory by the forward movement of the second link and its subsequent rotation. Thread cutting device for double chainstitch sewing machine. (2) The thread cutting device for a multi-row double-ring sewing machine according to claim 1, wherein the parallel link has a lateral protrusion, and a thread trimming knife is attached to the protrusion. (3) The guide means is attached to a pair of elongated holes or elongated grooves formed in one of the first link and the fixed member fixed to the sewing machine frame, and is attached to the other, and is slidable in the elongated holes or elongated grooves, respectively. A thread cutting device for a multi-row double chainstitch sewing machine as claimed in claim 1, which is a utility model registration device, and comprises a pair of pins that fit together. (4) The thread cutting device for a multi-row double chainstitch sewing machine according to claim 1, wherein the guide means is a cylindrical body into which a portion of the first link is slidably fitted. (5) The thread cutting device for a multi-row double chainstitch sewing machine according to claim 3, wherein the stopper means comprises one end of a long hole or long groove and a pin that engages with the end. (6) In the multi-row double chainstitch sewing machine according to claim 4, the stopper means comprises a protrusion shaped at the side end of the cylindrical body and the first link that engages with the stopper means. Thread cutting device.