JP3555992B2 - Thread removal method for chain stitch machines - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a chain stitch sewing machine that forms a chain stitch on a work cloth by connecting a large number of loops in a chain with a vertical movement and a cloth feed of a crochet provided with a hook portion. For example, the present invention relates to a method for removing a thread from a crochet.
[0002]
[Prior art]
The technique shown in FIGS. 7 and 8 is known as a conventional thread removing method. In the first conventional method shown in FIG. 7, for example, when one pattern is completed and the sewing machine moves to the next sewing place, an attempt is made to remove the thread by moving the crochet 31 up and down with the cloth feeding stopped. Can be That is, first, as shown in FIG. 7A, at the sewing end point of the previous handle, the crochet 31 is raised, and the thread T is drawn upward through the needle hole 32a of the needle plate 32 and the work cloth W. As a result, the final loop L is formed larger than usual due to the binding. Next, as shown in FIG. 3B, the crochet 31 is lowered, and the hook 31a is released from the final loop L. Subsequently, the crochet 31 is raised with the hook portion 31a facing forward in the sewing direction, and the thread T of the final loop L is removed from the crochet 31. Thereafter, the work cloth W is fed, and the sewing start point of the next pattern is positioned directly below the crochet 31.
[0003]
On the other hand, in the second conventional method shown in FIG. 8, when moving to the next sewing place, the thread is removed by feeding the work cloth W back and forth while holding the crochet 31 at a constant height. Done. That is, first, as shown in FIG. 3A, the work cloth W is fed from the sewing end point by a movement amount much larger than the normal pitch, and a long final loop L is formed. Next, as shown in FIG. 2B, the work cloth W is returned in the opposite direction, and a gap is formed between the hook 31a of the crochet 31 and the tip of the final loop L. Subsequently, as shown in FIG. 3C, the crochet 31 is rotated, and the hook 31a is turned rearward in the sewing direction. Thereafter, the work cloth W is fed while the crochet 31 is held at the same height, the thread T is removed from the crochet 31, and the sewing start point of the next pattern is positioned immediately below the crochet 31. The second conventional method is a known technique disclosed in Japanese Patent Application Laid-Open No. H05-51989.
[0004]
[Problems to be solved by the invention]
By the way, since the chain stitch is formed by connecting a large number of loops in a chain, the final loop may be pulled backward in the sewing direction by the previous loop. In such a case, according to the first conventional method, as shown in FIG. 7B, the thread T of the final loop L once disengaged from the hook portion 31a by the lowering of the crochet 31 causes the subsequent rise of the crochet 31. The hook portion 31a may be hooked again. When the work cloth W is sent to the next sewing place in a state where the thread T has been caught, the work cloth W is forcibly pulled by the thread T when the thread is not cut, and in the case after the thread cut, However, the yarn ends are pulled out to the front side of the work cloth W, and in any case, there is a problem that the finish is deteriorated.
[0005]
On the other hand, according to the second conventional method, since the crochet 31 is rotated after being retracted, and the hook portion 31a is directed rearward in the sewing direction, the thread T can be securely released from the hook portion 31a. However, in order to do this, the work cloth W has to be sent back and forth, which requires not only a special cloth feed control for thread removal, but also wastes considerable time in cloth feed. Further, it is necessary to form the loop L considerably long so that the loop L does not stand up due to the elasticity of the thread T (described in the lower right column of page 2 of the above-mentioned publication). However, there is also a problem that the garment protrudes greatly from the work cloth W and deteriorates the appearance of the sewing product. In order to avoid this problem, when the final loop L is formed to be short, the crochet 31 moves relatively at a fixed height position when feeding cloth for relocation, and thus the loop standing on the back side of the crochet 31 L may collide, and the yarn T may be cut by the impact at this time.
[0006]
Therefore, an object of the present invention is to provide a thread removing method in a chain stitch sewing machine that can reliably remove a thread from a crochet with a simple control without adversely affecting a finish when changing a sewing place or the like. .
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a thread removing method according to the present invention is configured to connect a large number of loops in a chain with a vertical movement and a cloth feed of a crochet provided with a hook portion, and to perform a chain stitch on a work cloth. In the chain stitch sewing machine forming the eyes, while the cloth feed is stopped, the crochet is raised, the thread is pulled out of the work cloth, the crochet is lowered, and after rotating the crochet so that the hook portion is directed backward in the sewing direction. The crochet is raised and the thread is removed from the crochet.
[0008]
Here, the term "rear in the sewing direction" includes a range of 90 to 270 with respect to the sewing direction, preferably a range of 120 to 240, and more preferably a range of 150 to 210. .
[0009]
[Action]
According to the thread removing method of the present invention, the crochet is rotated at the lowered position, the hook portion is turned rearward in the sewing direction, and then the crochet is raised, so that even when the loop is formed in a state inclined backward, the loop is formed. The thread can be securely removed from the crochet without hooking on the hook. Further, since the thread removal is performed in a state where the cloth feeding is stopped, no special cloth feeding control is required, and the yarn can be detached in a short time by a simple control of simply moving the crochet up and down and rotating. Furthermore, since the thread can be removed even when the loop is in the upright state, the loop can be formed to a minimum length to improve the appearance of the sewn product. In addition, when the cloth is fed after the yarn is removed, the crochet is raised, so that the collision between the crochet and the loop can be avoided, and the yarn breakage can be prevented.
[0010]
【Example】
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a head portion of a chain stitch embroidery sewing machine. A support frame 2 is attached to a front surface of the sewing head 1. A needle bar 4 is supported on the support frame 2 via a guide cylinder 3 so as to be vertically movable, and a crochet needle 5 having a hook portion 5a is attached to a lower end of the needle bar 4. A needle plate 6 is provided below the sewing machine head 1, and a looper 7 for supplying a thread to the crochet 5 is provided below the needle plate 6. The work cloth W is stretched over the embroidery frame 8 above the needle plate 6.
[0011]
A drive shaft 10 common to a plurality of heads of the multi-head embroidery sewing machine is provided behind the sewing machine head 1. The drive shaft 10 is connected to a main shaft 13 via gears 11 and 12, and a crank 14 is attached to a front end of the main shaft 13. An elevating frame 15 is interposed between the sewing machine head 1 and the support frame 2, and its horizontally long hole 15 a is connected to an eccentric pin 14 a of the crank 14. A connecting member 28 is pivotally attached to the upper end of the elevating frame 15 so as to be tiltable, and the connecting member 28 is urged in the counterclockwise direction in FIG. With this biasing, the hook portion 28a of the connecting tool 28 is removably engaged with the engaging pin 30a of the lifter 30 mounted on the guide bar 29 so as to be liftable.
[0012]
On the other hand, a slider 16 is externally fitted on the upper part of the guide cylinder 3, and the slider 16 is connected to the needle bar 4 by a screw 17 via a needle bar holding body 18. The fitting portion 30b of the lift 30 is fitted in the outer circumferential groove 16a of the slider 16. An operation shaft 33 is rotatably mounted on the support frame 9 of the sewing machine head 1, and a lifting lever 34 is fixed to the operation shaft 33. When the operation shaft 33 and the lifting lever 34 rotate clockwise in FIG. 1 with the hook 28a disengaged from the engaging pin 30a, the lifting lever 34 contacts the driven pin 30c at the upper end of the lift 30. The lift 30 is lifted upward by contact.
[0013]
Accordingly, when the hook portion 28a is engaged with the engagement pin 30a, the rotation of the main shaft 13 causes the lifting frame 15, the coupling tool 28, the lifting element 30, the needle bar 4 and the crochet 5 to move up and down integrally, With the vertical movement of the crochet 5 and the cloth feeding by the embroidery frame 8, a number of loops are connected in a chain, and a chain stitch is formed on the work cloth W. When the hook portion 28a is disengaged from the engagement pin 30a, the lifting shaft 34 does not move up and down even if the main shaft 13 rotates. The needle bar 4 and the crochet 5 are lifted up to a lifting position, for example, about 20 mm higher than the top dead center position at the time of sewing via the needle 30.
[0014]
The guide cylinder 3 is rotatably supported by the support frame 2 and is rotated by a direction control shaft 20 around a vertical axis via gears 21 and 22. The needle bar 4 is connected to the guide cylinder 3 so as to be integrally rotatable through fitting of the vertical groove 3 a of the guide cylinder 3 and the needle bar gripping body 18. At the time of sewing, the direction control shaft 20 is rotated at an angle based on the embroidery data, whereby the guide cylinder 3 and the needle bar 4 are integrally rotated, and the direction of the hook 5a of the crochet 5 is adjusted to the sewing direction. It is configured to be controllable.
[0015]
A slide cylinder 25 is supported at the lower end of the support frame 2 via a guide cylinder 24 so as to be vertically movable, and a nipple 26 is attached to the lower end thereof. To the upper end of the slide cylinder 25, a control member 27 for controlling the elevation of the nipple 26 independently of the needle bar 4 is connected. The nipple 26 holds the work cloth W and prevents the work cloth W from rising when the crochet 5 rises and comes out of the work cloth W, and always guides the vertical movement of the crochet 5 so that the crochet 5 swings. To prevent
[0016]
Next, an embodiment of a thread removing method of the chain stitch embroidery sewing machine configured as described above will be described with reference to FIGS. When the sewing of one pattern is completed, the cloth feed is stopped at that time, and in the case of a sewing machine equipped with a thread cutting device, the thread T is cut below the needle plate 6. Next, as shown in FIG. 2, the nipple 26 is raised. Subsequently, the operating shaft 33 and the lifting lever 34 are rotated to raise the crochet 5 to a lifting position higher than the top dead center position, as shown in FIG. 6a and the work cloth W are pulled out upward and the loop L is formed larger than usual for binding.
[0017]
Again, as shown in FIG. 4, only the crochet 5 is lowered to a position close to the work cloth W, and the hook portion 5 a is released from the loop L. With the crochet 5 lowered in this way, the direction control shaft 20 is rotated, and as shown in FIG. 5, the crochet 5 is rotated by 180 °, and the hook 5a is turned rearward in the sewing direction. Then, the operating shaft 33 and the lifting lever 34 are rotated, and as shown in FIG. 6, the crochet 5 is raised to a lifting position higher than the top dead center position, and the thread T is removed from the crochet 5. In this way, even when the loop L is formed to be inclined rearward due to the elasticity of the thread T, there is no possibility that the thread T is hooked on the hook portion 5a when the crochet 5 is raised, and the thread T can be securely removed from the crochet 5. Can be.
[0018]
After removing the thread, the work cloth W is fed, and the sewing start point of the next pattern is positioned directly below the crochet 5. At this time, since the thread T is completely disengaged from the crochet 5, the thread end after thread trimming is pulled out to the front side of the work cloth W, or the work cloth W is forcibly pulled when the thread is not trimmed. The embroidery pattern can be finished with a good appearance without fear of occurrence. Further, since the work cloth W is fed after the crochet 5 has been raised, the collision between the crochet 5 and the loop L can be reliably avoided, and yarn breakage can be prevented.
[0019]
As described above, according to the thread removing method of the present embodiment, since the thread removing is performed in the state where the cloth feed is stopped, no special cloth feed control is required, and the crochet 5 can be moved up and down using the existing mechanism. The thread T can be removed in a short time by a simple control that only rotates. Further, since the thread can be removed even when the loop L is upright, it is possible to improve the appearance of the sewn product by forming the loop L to a minimum length necessary for binding the thread.
[0020]
Note that the present invention is not limited to an embroidery sewing machine, and may be implemented in a chain stitch sewing machine of a type in which a work cloth is fed by a feed dog on a sewing machine bed, and other components within a range not departing from the spirit of the present invention. Can be embodied by appropriately changing the shape and configuration.
[0021]
【The invention's effect】
As described above in detail, according to the thread removing method of the chain stitch sewing machine of the present invention, when changing the sewing location, the crochet is rotated at the lower position, and the hook portion is turned rearward in the sewing direction. As a result, the yarn can be reliably removed from the crochet with a simple control without adversely affecting the finish.
[Brief description of the drawings]
FIG. 1 is a sectional view of a main part of a chain stitch embroidery sewing machine in which a thread removing method according to an embodiment of the present invention is performed.
FIG. 2 is a sectional view showing an initial operation of the yarn removing method.
FIG. 3 is a sectional view showing a second operation of the yarn removing method.
FIG. 4 is a sectional view showing a third operation of the yarn removing method.
FIG. 5 is a sectional view showing a fourth operation of the yarn removing method.
FIG. 6 is a sectional view showing a fifth operation of the yarn removing method.
FIG. 7 is a sectional view showing a yarn removing method of the first conventional example.
FIG. 8 is a sectional view showing a yarn removing method according to a second conventional example.
[Explanation of symbols]
4 Needle bar 5 Crochet 5a Hook 6 Needle plate 8 Embroidery frame 13 Main shaft 20 Direction control shaft T Thread L Loop W Work cloth

Claims (1)

With the vertical movement of the crochet equipped with the hook part and the cloth feed, a number of loops are connected in a chain, and in a chain stitch sewing machine that forms a chain stitch on the work cloth, with the cloth feed stopped, It is characterized by raising the crochet, pulling out the thread from the work cloth, lowering the crochet, rotating the crochet so that the hook portion is directed backward in the sewing direction, and then raising the crochet and removing the thread from the crochet. Thread removal method for chain stitch machines.

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