JP6785439B2 - Fabric sewing method and double chain sewing machine - Google Patents

Description

In the present invention, for example, using a double-ring sewing machine represented by a two-needle type horizontal tubular shape, the front and rear body parts are sewn first to form a loop like a T-shirt or underwear. Regarding the sewing method of fabrics including round fabrics such as hemming stitching to prevent fraying of the edges of the round fabrics and the double chain stitch sewing machine used for sewing, especially the ends of the looper thread cut after sewing. Regarding the processing technology of parts.

For example, taking the hem pull stitching of a round fabric using a two-needle type double chain stitch sewing machine as an example, the sewn portion of the round fabric (the overlapped fabric in which the edge portion is folded back and overlapped on the back side of the fabric). While feeding the portion) in a predetermined sewing progress direction along the upper surface of the needle plate, a plurality of needle thread loops are formed under the needle plate by the vertical movement of a plurality of needles arranged in parallel in a direction orthogonal to the sewing progress direction. The plurality of needle thread loops are captured by advancing the looper capable of advancing and retreating in a direction substantially orthogonal to the sewing progress direction between one side portion and the other side portion in the parallel direction of the plurality of needles. By looping the captured plurality of needle thread loops with the looper thread held by the looper, a double chain stitch is formed on the entire circumference of the sewn portion (overlapped fabric portion) of the round fabric.

As shown in FIGS. 21 (A) and 21 (B), the two-needle type double chain stitch sewing machine that forms the double chain stitch as described above has left and right needle threads NTa and NTb (FIG. 22). Two left and right needles 1a and 1b arranged in parallel in a direction orthogonal to the sewing progress direction H and a looper thread LT (see FIG. 22) so as to hold and reciprocate up and down with respect to the needle plate 2. ) Can be moved forward and backward in a direction substantially orthogonal to the vertical and forward double movement path of the needles 1a and 1b, and the needle thread loops NTa'and NTb' formed by the needles 1a and 1b under the needle plate 2 during the advance movement. A looper 3 for capturing (see FIG. 22), an advance position P1 to the left front close to the needle plate 2 and the looper 3, and a retract position P2 to the right rear of the advance position P1. The needle thread loop is provided with a thread trimming device 4 that can be reciprocally driven and is moved from the retracted position P2 to the advanced position P1 to perform a cutting action after the completion of a predetermined sewing operation, that is, at the end of sewing. By looping NTa'and NTb' with the looper thread LT held by the looper 3, a double chain stitch A having a predetermined length is formed on the sewing fabric W.

The thread trimming device 4 has needle thread portions NTa1, NTb1 and looper thread portions LT1 protruding toward the back surface side of the sewing fabric W at the end of sewing in which a double chain stitch A having a predetermined length is formed on the sewing fabric W. In the thread trimming device 4, the movable scalpel 5, the fixed scalpel 6, and the end of the looper thread portion LT1 arranged and cut at the lower part of the movable scalpel 5 are referred to as the movable scalpel 5. It has a looper thread pinching member 7 made of a leaf spring that is elastically pinched and held between the threads, and a thread pinching auxiliary spring 8 for adjusting the pinching holding force of the looper thread pinching member 7. Then, the thread trimming device 4 including the movable female 5, the fixed female 6, the looper thread pinching member 7, and the thread pinching auxiliary spring 8 is reciprocally driven and moved between the retracted position P2 and the advanced position P1. After the thread trimming device 4 is moved to the advance position P1, only the movable scalpel 5 is moved between the external position (advanced position) closer to one side of the needle drop position and the external position closer to the other side of the needle drop position. A reciprocating drive moving mechanism 9 for reciprocating drive movement is provided.
Since the reciprocating drive moving mechanism 9 has the same configuration as the reciprocating drive moving mechanism in the embodiment of the present invention described later, the corresponding constituent members include the reciprocating drive moving mechanism described in the embodiment of the present invention. It has the same code.

As shown in FIGS. 21A and 21B, the thread trimming device 4 of the conventional double chain sewing machine having the above-mentioned basic configuration has the movable knife 5 on the side edge of the tip of the movable knife 5. Is a looper thread that catches by hooking the looper thread portion LT1 projecting to the back surface side of the sewing fabric W when the needle is driven and moved backward from the external position closer to the other side to the outer position closer to one side. The catching portion 10 is formed, and the movable scalpel 5 is closer to the side edge of the movable scalpel 5 than the looper thread catching portion 10 toward the base end, and the movable scalpel 5 is closer to one side than the other side of the needle drop position. A needle thread catching portion 11 is formed (for example,) that sequentially hooks and catches the left and right needle thread portions NTa1 and NTb1 protruding toward the back surface side of the sewing fabric W when it is driven and moved backward to an external position (for example). , Patent Document 1).

Next, the thread trimming operation by the thread trimming device 4 of the conventional double chain sewing machine described above will be described.
First, as shown in FIG. 22 (a), the thread trimming device 4 is moved to the advance position P1 which is an external position closer to one side of the needle drop position at the end of sewing, and then as shown in FIG. 22 (b). In addition, only the movable scalpel 5 is driven and moved in the direction of the arrow x from the advance position P1 toward the other side-side external position of the needle drop position. Due to this forward drive movement, as shown in FIG. 22C, the looper thread catching portion 10 on the tip side of the movable female 5 is hung between the vicinity of the tip of the looper 3 and the back surface side of the sewing fabric W. Immediately after crossing the looper thread portion LT, the moving direction of the movable female 5 is reversed, and the looper thread portion LT1 is hooked on the looper thread catching portion 10 and captured. Subsequently, as shown in FIG. 22D, the movable scalpel 5 is driven to go-around in the direction of the arrow y from the external position closer to the other side of the needle drop position toward the advance position P1, and this go-around drive movement. Occasionally, the left and right needle thread portions NTa1 and NTb1 protruding toward the back surface side of the sewing fabric W are hooked and captured by the needle thread capturing portion 11. Then, the movable female 5 is further driven and moved in the direction of the arrow y, so that the needle thread portions NTa1, NTb1 and the looper thread captured by the needle thread capturing unit 11 are captured as shown in FIG. 22 (e). The looper thread portion LT1 captured by the portion 10 is cut by the sliding contact between the trapped portions 11 and 10 and the fixing female 6. After that, as shown in FIG. 22 (f), the needles 1a and 1b move upward of the needle plate 2, and the tip of the cut end portion LT2 of the looper thread LT1 held by the looper 3 is a movable female 5. It is elastically sandwiched and held between the looper thread sandwiching member 7 and the looper thread sandwiching member 7 to prepare for the next sewing. Then, as the fabric moves in the sewing progress direction H with the start of the next sewing, the tip of the looper thread cutting end portion LT2 elastically sandwiched and held between the movable female 5 and the looper thread sandwiching member 7. Is naturally pulled out from between the movable female 5 and the looper thread pinching member 7 (pinching and holding is released).

Jitsufuku No. 6-32072

In the conventional double chain sewing machine having the above configuration, the cutting positions of the needle thread portions NTa1, NTb1 and the looper thread portion LT1 by the thread trimming device 4 do not enter the vertical and forward double movement paths of the needles 1a and 1b. As described above, the left and right needle thread portions NTa1 and NTb1 and the cut end portion LT2 of the looper thread portion LT1 after cutting are predetermined because the position is far from the needle drop position and is further to the right outer position than the right needle 1b. It becomes a thread residue with a length. In particular, the cut end portion LT2 of the looper thread is elastically sandwiched and held between the movable female 5 and the looper thread pinching member 7 at the outer position on the right side of the right needle 1b with the tip portion separated from the needle drop position. Therefore, when sewing the next fabric portion, the looper thread cutting end portion LT2 does not form a part of the double chain stitch A of the sewing start portion, and as shown in FIG. It sticks out like a long beard to the outside, resulting in poor finish such as deterioration of the appearance and quality of the sewn product.

In particular, when the looper yarn is a type of yarn in which a plurality of ultrafine filaments are bundled, when the looper yarn is cut by a thread trimmer, the cut end portion of the looper yarn is separated into a plurality of ultrafine fiments, and the separated plurality of the looper yarns are separated. The filaments may protrude from the outside of the stitch in different directions or stand up from the surface of the fabric, resulting in a very poor appearance and further deterioration in finish.

In order to eliminate such a poor finish, conventionally, after the sewing is finished, the sewing maker manually cuts the cut end portion of the looper thread protruding from the stitch of the sewing material W by using, for example, hand scissors. It was done. However, in this case, it takes troublesome manual work to cut the thread every time the sewing of one sewn product is finished, which not only lowers the sewing work efficiency but also increases the work load on the sewing maker. In addition, there is a problem that the degree of freedom of the hands of the sewing maker is hindered, the operability of the fabric is deteriorated, and the sewn fabric is easily damaged by hand scissors or the like.

The present invention has been made in view of the above circumstances, and the cut end portion of the looper thread is cut at the end of sewing by using a hand scissors or the like, which reduces the sewing work efficiency, increases the work load, and improves the operability of the fabric. A method of sewing a fabric that can keep the remaining length of the cut end of the looper thread short so that the appearance does not deteriorate, regardless of the type of thread, without the troublesome manual work that causes deterioration and damage to the fabric. And to provide a double chain stitch sewing machine.

In order to achieve the above object, in the method for sewing a fabric according to the first invention, the fabric is fed in a predetermined sewing progress direction along the upper surface of the needle plate and arranged in parallel in a direction substantially orthogonal to the sewing progress direction. A plurality of needle thread loops are formed under the needle plate by the vertical movement of the plurality of needles, and the sewing progresses between one side portion and the other side portion in the parallel direction of the plurality of needles. The plurality of needle thread loops are captured by the advancement of loopers capable of advancing and retreating in directions substantially orthogonal to the direction, and the plurality of captured needle thread loops are looped by the looper threads held by the looper to form a plurality of needle thread loops on the fabric. A method of sewing a fabric for forming a double chain stitch of a needle, which is arranged on the other side of the needle in a parallel direction when the looper is located at a substantially advanced end after sewing is completed. The first step of freeing the cut end portion of the looper thread that is cut by the thread trimming device and connected to the thread hole at the tip of the looper, and the cut end portion of the looper thread in the free state are set in the sewing progress direction of the looper. The second step of shifting to the lower side so as to be in a posture along the substantially sewing progress direction, and the third step of holding the vicinity of the tip of the cut end portion of the looper thread shifted to the lower side of the sewing progress direction. By operating the needle and the looper at least half a turn to form a step and an empty ring or to form a seam on the next fabric, the plurality of intermediate portions of the looper thread held near the tip portion are formed. Of the needles in the book, the needles are guided to a set position within the range connecting the neighboring parts of both end needles in the parallel direction, and the movement of the middle part of the looper thread from the guided set position is prevented except in the sewing progress direction. Of the fourth step of holding the needle and the looper in the rotating state following the fourth step, the needle is lowered from the position where the needle is near the top dead point and the looper is near the advanced end. The fifth step of releasing the holding of the cut end portion of the looper thread with respect to the vicinity of the tip portion at the set operation position within the rotation operation range until the looper reaches the position near the retracting end and near the point. The fifth and subsequent steps are characterized in that a predetermined sewing is performed with the cut end portion of the looper thread in a free state.

Further, in the method for sewing the fabric according to the second invention, the overlapped fabric portion in which the edge portion of the round fabric is folded back and overlapped on the back surface side of the fabric is formed along the upper surface of the needle plate in a predetermined sewing progress direction. A plurality of needle thread loops are formed under the needle plate by the vertical movement of a plurality of needles arranged in parallel in a direction substantially orthogonal to the sewing progress direction, and one of the parallel directions of the plurality of needles is formed. The plurality of needle thread loops are captured by the advance of a looper capable of advancing and retreating in a direction substantially orthogonal to the sewing progress direction between the side portion and the other side portion, and the captured plurality of needle thread loops are captured by the looper. This is a method of sewing a fabric in which a double-ring stitch is formed on the entire circumference of the overlapped fabric portion of the round fabric by looping with a looper thread held by the looper, and the looper is omitted after the sewing is completed. When the needle is located at the advanced end, the cut end portion of the looper thread that is cut by the thread trimming device arranged on the other side portion in the parallel direction of the needle and is connected to the thread hole at the tip end portion of the looper is freed. One step, the second step of shifting the cut end portion of the free state looper thread toward the lower side of the looper in the sewing progress direction so as to be in a posture along the substantially sewing progress direction, and the sewing progress direction. A third step of holding near the tip of the cut end of the looper thread that has been transferred to the lower side, and at least half a turn of the needle and looper to form an air ring or a stitch on the next fabric. By operating the needle, the middle portion of the looper thread held near the tip portion is guided to a set position within the range connecting the vicinity portions of the both end needles in the parallel direction among the plurality of needles. Of the fourth step of holding the movement of the intermediate portion of the looper thread from the guided set position in a state of being blocked except for the sewing progress direction, and the rotation operation of the needle and the looper following the fourth step, the said At the set operation position within the rotational operation range from the position where the needle is near the top dead point and the looper is near the advance end to the position where the needle is near the bottom dead point and the looper is near the retract end. It has a fifth step of releasing the holding of the cut end portion of the looper thread with respect to the vicinity of the tip portion, and after the fifth step, a predetermined sewing is performed with the cut end portion of the looper thread in a free state. It is characterized by that.

Further, the double chain stitch sewing machine according to the third invention is arranged in parallel with a needle plate that sets a fabric and guides feeding in a predetermined sewing progress direction and needle threads in a direction substantially orthogonal to the sewing progress direction. A plurality of needles that are held and moved up and down, and a direction that holds the looper thread and is substantially orthogonal to the sewing progress direction between one side portion and the other side portion in the parallel direction of the plurality of needles. A looper that can move forward and backward and catches a plurality of needle thread loops formed by the needle under the needle plate during the advance movement, and a looper thread and needle thread that are arranged on the other side of the needle in the parallel direction and cut after sewing. A double chain stitch is formed on the fabric by looping the plurality of needle thread loops captured by the advance operation of the looper with the looper thread held by the looper. When the looper is located at the substantially advanced end after the sewing is completed, the double chain stitching sewing machine is cut by the thread trimming device and connected to the thread hole at the tip of the looper in a free state. A means for shifting the cut end portion of the looper thread and the sewing progress direction for shifting the cut end portion of the looper thread so as to move toward the lower side in the sewing progress direction of the looper so as to be in a posture along the substantially sewing progress direction. A looper thread holding means capable of holding and releasing the vicinity of the tip of the cut end portion of the looper thread transferred to the lower side, and the needle for forming an air ring or forming a stitch on the next fabric. And by operating the looper at least half a turn, the middle part of the looper thread holding the vicinity of the tip portion is set within the range connecting the vicinity portions of the needles at both ends in the parallel direction among the plurality of needles. It has a looper thread guiding portion that guides the looper thread to a position and a looper thread holding groove portion that holds the looper thread holding groove portion that is guided to a set position by the guiding portion so that the pull-out movement of the intermediate portion of the looper thread is blocked except in the sewing progress direction. With the looper thread holding member and the looper thread holding member holding the middle portion of the looper thread, the needle and the looper are rotated to move the needle to a position near the top dead point and the looper near the advance end. Control to release the holding by the looper thread holding means at the set operation position within the rotation operation range until the needle reaches the position near the bottom dead point and the looper reaches the position near the retracting end. It is characterized in that the means is provided, and after the control operation of the control means, a predetermined sewing is performed on the next fabric while the cut end portion of the looper thread is left in a free state.

Further, in the double chain stitch sewing machine according to the fourth invention, the overlapped fabric portion in which the edge portion of the round fabric is folded back and overlapped on the back surface side of the fabric is set and the feed is fed in a predetermined sewing progress direction. A needle plate to guide, a plurality of needles arranged in parallel in a direction substantially orthogonal to the sewing progress direction, holding the needle thread and moving up and down, and one side of the plurality of needles in the parallel direction holding the looper thread. A looper that can advance and retreat in a direction substantially orthogonal to the sewing progress direction between the portion and the other side portion, and catches a plurality of needle thread loops formed by the needle under the needle plate during the advance operation, and the needle. The looper is provided with a thread trimming device that is arranged on the other side of the parallel direction and cuts the looper thread and the needle thread after sewing, and the looper holds the plurality of needle thread loops captured by the advance operation of the looper. It is a double chain stitch sewing machine for sewing round cloth, which is configured to form a double chain stitch on the entire circumference of the overlapped cloth portion of the round cloth by looping with the looper thread. When the looper is located at the substantially advanced end after the sewing is completed, the cut end portion of the looper thread that has been cut by the thread trimming device and connected to the thread hole at the tip of the looper to be in a free state is described. A means for shifting the cut end portion of the looper thread to shift the looper toward the lower side in the sewing progress direction so as to be in a posture along the substantially sewing progress direction, and a cutting of the looper thread shifted to the lower side in the sewing progress direction. The looper yarn holding means capable of holding and releasing the vicinity of the tip of the end portion, and the needle and the looper being operated at least half a turn to form an air ring or a stitch on the next fabric. The looper thread guide portion and this guide guide the middle portion of the looper thread held near the tip portion to a set position within the range connecting the vicinity portions of the needles at both ends in the parallel direction among the plurality of needles. The looper thread holding member having the looper thread holding groove portion that holds the looper thread in the middle portion guided to the set position by the portion in a state of being blocked except for the sewing progress direction, and the looper thread holding member. While the middle part of the looper thread is held, the needle and the looper are rotated to move the needle from a position near the top dead point and the looper near the advance end, and the needle near the bottom dead point and the looper. The control operation of the control means is provided with a control means for controlling the release of the holding by the looper yarn holding means at the set operation position within the rotation operation range until the yarn reaches the position near the retracting end. After that, the cut end portion of the looper yarn is left in a free state for the next fabric. It is characterized in that it is configured to perform a predetermined sewing.

According to the fabric sewing method and the double chain sewing machine according to the first to fourth inventions having the above-mentioned characteristics, after a predetermined sewing operation (after the sewing is completed), the other side in the parallel direction of a plurality of needles. The cut end of the looper thread that has been cut by the thread trimming device at the part (outside to the right of the needle drop position) and is connected to the thread hole at the tip of the looper and is in a free state, is directed toward the lower side in the sewing progress direction of the looper. In order to shift to a posture along the approximate sewing progress direction and to hold the vicinity of the tip of the cut end portion of the transferred looper thread at the transition position, and then to form an empty ring or to form a stitch on the next fabric. By operating the needle and the looper at least half a turn, the middle part of the looper thread whose tip is held is set within the range connecting the vicinity parts of the needles at both ends in the parallel direction among the plurality of needles. It is guided to a position, and at the guided position, the middle part of the looper thread is held in a state of preventing the pull-out movement in a direction other than the sewing progress direction, and the needle is the top dead point in the subsequent rotation operation of the needle and the looper. At the set operation position within the rotation operation range from the vicinity to the position near the bottom dead point and from the position near the advance end to the position near the exit end, the cut end portion of the looper thread The holding near the tip of the looper thread is released, and then the predetermined sewing is performed on the next fabric while the cut end of the looper thread is left in a free state. It is possible to shorten the length of the cut end portion of the looper thread, that is, the thread residue of the looper thread as much as possible by releasing it at the stage before the sewing operation for the next fabric. Further, by moving the cut end portion of the looper thread sequentially from the guided holding position in the sewing progress direction, the looper thread end is moved near the left and right needle thread portions formed by the needles at both ends in the parallel direction during a predetermined sewing operation. It is possible to keep the position within the range connecting the outer sides of the left and right needle thread portions, which is the largest in the range connecting the portions, that is, within the approximate width of the stitch formed by the next sewing operation. ..

As described above, the remaining length of the cut end portion of the looper thread cut by the thread trimmer can be shortened as much as possible, and the thread end can be kept at a position within the substantially width of the stitch. Even when a looper thread of a type that can be separated into multiple ultrafine fiments by cutting is used as the thread, the tip of the cut end portion of the looper thread including the multiple extrafine filaments is large to the outside of the stitch. It is possible to prevent the appearance from being deteriorated due to sticking out or rising from the surface of the fabric, resulting in poor finish. Therefore, it is necessary for the sewing maker to perform a troublesome and time-consuming manual work of cutting the cut end portion of the looper thread short by using, for example, hand scissors, after the sewing is completed or before the sewing of the next fabric is started. The operability of the fabric is improved because the sewing work efficiency can be improved by that amount, the work load on the sewing maker can be reduced, and the degree of freedom of the sewing maker's hands is increased. It is possible to improve the sewn finish, and since the sewn fabric is not damaged by hand pinching or the like, the appearance and quality of the sewn product can be improved.

In particular, when hemming sewing is performed on a round fabric as a sewing target as in the second and fourth inventions, the sewing start portion and the sewing end portion are sewn in a slightly overlapping manner. At this time, the sewing start is started. Guide and hold the cut end of the looper thread of a predetermined length after pre-sew that protrudes outward from the stitch of the part to the set position within the range connecting the vicinity of each of the needles at both ends in the parallel direction. By sequentially pulling out and moving from the induction holding position in the sewing progress direction, the cut end portion of the looper thread can be processed so as to have a short length and the thread end stays within the substantially width of the stitch. Therefore, it is necessary to interrupt the sewing operation once in the middle of sewing, cut the cut end portion of the looper thread short using a hand scissors, etc., and then restart the sewing operation to perform lap stitching, which is troublesome and time-consuming work. It is no longer possible to sew the hem of the round fabric all at once, including the lap stitch at the end of sewing, and there is no time loss for looper thread processing. The work can be done very efficiently.

In the method of sewing the fabric according to the first invention and the second invention, the feed amount of the fabric at the sewing start portion of the predetermined sewing performed with the cut end portion of the looper thread in the free state in the fifth and subsequent steps. Is preferably set to be smaller than the feed amount of the fabric at the time of normal sewing.
In this case, since the amount of fabric feed when performing a predetermined sewing with the cut end portion of the looper thread left in a free state is smaller than in the normal case, the tip of the cut end portion of the looper thread is a needle at both ends in the parallel direction. It is located in the stitches in a form in which they are intricately entwined with each other, and it is possible to prevent the remaining end of the thread from protruding to the left and right of the needle thread portion, and further improve the appearance.

Further, in the method for sewing the fabric according to the first invention and the second invention, in the fourth step, the middle portion of the looper thread in which the vicinity of the tip portion is held is in the parallel direction among the plurality of needles. It is preferable that the looper thread is guided to a position between the needles at both ends and the movement of the intermediate portion of the looper thread is prevented from the guided position except in the sewing traveling direction.
In this case, since the position where the middle part of the looper thread is sequentially pulled out and moved in the sewing progress direction as the holding of the vicinity of the tip of the looper thread is released is between the needles at both ends in the parallel direction, a short looper thread is used. The end can be securely fastened to a position within the width of the stitch formed by the next sewing operation so that the stitch does not protrude outward.

Further, in the double chain sewing machine according to the third and fourth inventions, the transfer means of the cut end portion of the looper thread is an air ejection nozzle, and between the air ejection nozzle and the looper thread holding means. Is provided with a looper thread guide member having a passage through which the cut end portion of the looper thread blown off by the air ejected from the air ejection nozzle is corrected to a substantially horizontal posture along the sewing progress direction. Is preferable.
In this case, since the cut end portion of the looper thread is blown off by the air ejected from the nozzle, the looper thread can be reliably moved to the lower side in the sewing progress direction regardless of the type of thread, and the air ejection nozzle can be moved. Since it can be installed in a fixed position and does not require a moving part, the structure is simple and the space is small, and it is suitable for installation inside the sewing machine bed. In addition, by guiding the cut end of the looper thread that is blown off by the air through the passage of the looper thread guide member, the cut end of the looper thread that tends to wobble is reliably corrected to a horizontal posture along the substantially sewing progress direction as specified. can do.

Further, as the double chain stitch sewing machine according to the third invention and the fourth invention, even if it is a two-needle type horizontal tubular double chain stitch sewing machine applied to hemming stitching at the end of a round cloth. A two-needle type flatbed type double chain stitch sewing machine may be used.

It is a perspective view of the whole of the two-needle type horizontal cylinder type double chain sewing machine which concerns on embodiment of this invention, in the state which the upper surface part of the sewing machine bed part is removed. It is a perspective view of the main part in the state where the sewing machine arm part of the horizontal cylinder type double chain stitch sewing machine of the same two-needle type is cut off. The same as above shows a state in which the thread trimming device of the two-needle type horizontal tubular double-ring sewing machine is retracted to the retracted position, (A) is a plan view of the main part, and (B) is FIG. 3 (A). It is a vertical sectional view along the line III-III of. The same as above shows a state in which the thread trimmer is advanced to the advanced position and the movable scalpel is driven and moved to the leftmost position, (A) is a plan view of the main part, and (B) is FIG. 4 (A). It is a vertical sectional view along the IV-IV line of. It is an exploded perspective view explaining the structure of the reciprocating drive moving mechanism in the thread trimming apparatus. It is the figure which looked at the example of the stitch structure of the double chain stitch from the back side of the sewing cloth. It is the figure which looked at the other example of the stitch structure of a double chain stitch from the back side of the sewing cloth. It is the figure which looked at another example of the stitch structure of a double chain stitch from the back side of a sewn cloth. Another example of the stitch structure of double chain stitching is a view seen from the back side of the sewn fabric. It is an external perspective view which shows the state of the hemming stitch of a round cloth. It is an enlarged perspective view of the main part which shows the state immediately after the thread trimming is completed after the sewing is finished. It is an enlarged perspective view of the main part which shows the state which shifts the looper thread cutting end portion to the lower side in the sewing progress direction of a looper. It is an enlarged perspective view of the main part which shows the state which sandwiched and held the vicinity of the tip end part of the looper thread cutting end part shifted to the lower side in the sewing progress direction of a looper. The same state as in FIG. 13 is shown, (A) is an enlarged perspective view of a main part viewed from the sewing progress direction, and (B) is a view taken along the line VV of FIG. 14 (A). The middle part of the looper thread cutting end is guided between the left and right needles, (A) is an enlarged perspective view of the main part as seen from the sewing progress direction, and (B) is VI- of FIG. 15 (A). It is a VI line arrow view. A state in which the middle portion of the looper thread cutting end portion is guided between the left and right needles and enters the holding groove portion is shown, (A) is an enlarged perspective view of the main portion as viewed from the sewing progress direction, and (B) is FIG. It is a VII-VII line arrow view of (A). It shows a state in which the looper has advanced to the vicinity of the needle drop, (A) an enlarged perspective view of a main part viewed from the sewing traveling direction, and (B) is a view taken along the line VIII-VIII of FIG. 17 (A). FIG. 6 is a perspective view of a main part showing a state in which the sewing machine operates once from the state of FIG. 14 and the looper reaches the vicinity of the advanced end. FIG. 5 is a perspective view of a main part showing a state in which the sewing machine is further operated by one rotation from the state of FIG. 18 and the looper reaches the vicinity of the advancing end, and the seam at that time. FIG. 5 is a perspective view of a main part showing a state in which the sewing machine is further operated one rotation from the state of FIG. 19 and the looper reaches the vicinity of the advancing end, and the seam at that time. A state in which the entire thread trimming device of the conventional double-ring sewing machine is advanced to the advanced position is shown, (A) is a plan view of the main part, and (B) is a vertical sectional view along the IX-IX line of FIG. is there. (A) to (f) are perspective views of the main part which sequentially shows the thread trimming operation of the thread trimming apparatus of the conventional double chain sewing machine. It is the figure which looked at the example of the stitch structure of the conventional double chain stitch from the back side of the sewing cloth.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, the same components as those of the conventional double chain sewing machine will be described with the same reference numerals.
FIG. 1 is a perspective view of the entire two-needle type horizontal tubular double-ring sewing machine according to the present invention in a state where the upper surface portion of the sewing machine bed portion is removed, and FIG. 2 is a two-needle type horizontal tubular type sewing machine. It is a perspective view of the main part in the state where the sewing machine arm part of the double chain stitch sewing machine is cut off.

In the two-needle type horizontal tubular double-ring sewing machine M, the sewing machine arm portion 21 and the sewing machine bed portion 22 extend substantially parallel to each other from the upper part and the lower part of the sewing machine body 20 toward the left side. .. Inside the sewing machine arm portion 21, two left and right needles 1a and 1b (see FIGS. 3 and 4) arranged in parallel with the sewing machine spindle and a direction substantially orthogonal to the sewing progress direction are reciprocated up and down. A drive mechanism, a presser drive mechanism that reciprocates a cloth presser (not shown) up and down, a power transmission mechanism to each of these drive mechanisms, etc. are incorporated, but these drive mechanisms and power transmission mechanisms are well known, so explanations will be given. Omit.

A needle plate 2 having a needle drop groove portion forming a needle drop position is fixed to the upper surface of the sewing machine bed portion 22, and a looper thread LT is placed in the sewing machine bed portion 22 below the needle plate 2. FIG. 4 (FIG. 4) shows a looper 3, a thread trimming device 4, and a blade edge portion 6e of a fixing female 6 of the thread trimming device 4, which are held and moved in and out in the left-right direction substantially orthogonal to the vertical and forward double motion path of the needles 1a and 1b. As shown in A) and (B), the advance position P1 to the left front where the contact member 34 described later abuts on the stopper member 33 described later at a position close to the needle plate 2 and the looper 3 and FIG. As shown in (A) and (B), a state in which the thread trimming device 4 is moved to the advanced position P1 while being reciprocally driven to move between the retracted position P2 on the right rear side of the advanced position P1. Reciprocating drive movement in which only the movable knife 5 described later is linearly reciprocated in the xy direction between the external position closer to one side (right side) and the external position closer to the other side (left side) of the needle drop position. A mechanism 9 and the like are incorporated.

In the two-needle type double chain sewing machine M having the above configuration, the needle thread loops NTa'and NTb' formed by the needles 1a and 1b under the needle plate 2 are looped by the looper thread LT held by the looper 3. As a result, as shown in FIGS. 6 to 9, a double chain stitch A having a predetermined length is formed on the sewing fabric W.

In the thread trimming device 4, the thread trimming device 4 is close to the needle plate 2 and the looper 3 via the reciprocating drive moving mechanism 9, and the advance position P1 and the retracted position to the right rear of the advance position P1. It is configured so that it can be reciprocally driven and moved to and from P2. Then, the thread trimming device 4 is used for thread cutting to cut the left and right needle thread portions NTa1, NTb1 and the looper thread portion LT1 projecting to the back surface side of the sewing fabric W after the predetermined sewing operation is completed, that is, at the end of sewing. The movable knife 5 and the fixed blade portion 6e are arranged at the position closest to the needle drop position within the range of the right needle 1b among the left and right needles 1a and 1b at the advance position P1 so as not to enter the vertical movement path. It has a scalpel 6. Further, the looper thread pinching member 7 made of leaf spring and the thread pinching auxiliary spring 8 for adjusting the pinching holding force of the looper thread pinching member 7 provided in the conventional double chain stitch sewing machine shown in FIG. 21 are also provided. The looper thread pinching member 7 and the thread pinching auxiliary spring 8 are moved to a position where the cut end portion LT2 of the looper thread LT1 after cutting is not pinched and held. Therefore, as shown in FIG. 11, the cut end portion LT2 of the looper thread LT1 cut by the thread trimming device 4 after the sewing is completed is connected to the thread hole 3a at the tip of the looper 3 and hangs down in a free state. Although the looper thread pinching member 7 and the thread pinching auxiliary spring 8 are moved to a position where the looper thread cutting end portion LT2 is not sandwiched and held, the movable female 5 is fixed in order to ensure the looper thread cutting. The state of elastically pressurizing the scalpel 6 is moved to a position where it can be maintained.

The movable scalpel 5 is composed of a strip-shaped plate material that is long in the left-right direction, and the movable scalpel 5 is placed on the side edge portion of the movable scalpel 5 made of the long strip-shaped plate material near the tip, as in the conventional case. A looper thread catching portion 10 is formed to hook and catch the looper thread portion LT1 protruding from the back surface side of the sewing fabric W when the looper thread portion LT1 projects from the lateral external position to the one side external position. At the same time, the movable scalpel 5 returns to the side edge portion of the movable scalpel 5 closer to the base end than the looper thread catching portion 10 from the other side-side external position of the needle drop position to the one-side-side external position. A needle thread catching portion 11 is formed which sequentially hooks and catches the left and right needle thread portions NTa1 and NTb1 protruding toward the back surface side of the sewing fabric W when it is driven and moved, and the movable knife 5 is in the advance position. When the needle thread catching portion 11 captures the needle thread portion 11 and moves the needle thread portion NTb1 on the right and left sides when the needle thread drop position is moved backward from one side (right side) side external position to the other side (left side) side outside position. , NTa1 and the looper thread part LT1 captured by the looper thread catching part 10 are moved to a position closer to the other side (right side) than the one side (right side) side (right side) side of the needle drop position and the needle thread catching part. It is configured to cut by sliding contact between the 11 and the looper thread catching portion 10 and the blade edge portion 6e of the fixed blade 6.

The thread trimming device 4 is reciprocally driven and moved between the advance position P1 and the retracted position P2, and in a state where the thread trimmer 4 is moved to the advance position P1, only the movable knife 5 is needled. The reciprocating drive moving mechanism 9 that linearly reciprocates in the xy direction between the external position closer to one side (right side) and the external position closer to the other side (left side) of the drop position is shown in FIG. 3 (A). , (B), FIGS. 4 (A), (B) and 5 are configured.
That is, the lower surface of the right end portion of the movable female 5 is fixed to the movable female base 24 via a screw 23. A U-shaped notch 25 is formed in a substantially central portion of the movable female base 24 in the longitudinal direction (left-right direction), and the movable female base 24 is located in the left-right position sandwiching the notch 25 in the longitudinal direction of the movable female base 24. A pair of long left and right slits 26a and 26b are formed along the line.

The fixed female 6 is arranged on the upper surface of the movable female 5, and a female base guide 27 is superposed on the lower surface of the right end portion of the fixed female 6, and the fixed female 6 and the female base guide 27 are arranged. It is fixed to the left end of the fixing female base 29 via a screw 28. The movable female base 24 is a cylindrical nut 31a with a brim that is inserted from the upper surface side into one end of a pair of left and right links 40a and 40b and a headed bolt 48 that is inserted into the back surface (lower surface) of the fixed female base 29. , 31b allows the cylindrical nuts 31a and 31b with brim to rotate at one end of the pair of left and right links 40a and 40b, and the pair of left and right slits 26a and 26b in the movable female base 24. It is sandwiched in a state where it can be slidably moved within the length range of.

The other ends of the pair of left and right links 40a and 40b are inserted from the upper surface side thereof, and sleeves 41a and 41b with brims that allow rotation within the other ends of the pair of left and right links 40a and 40b are screwed 42a. It is screwed to the device mounting base 30 via 42b, whereby the movable female base 24 and the fixed female base 29 can reciprocate in the left-right direction as the pair of left and right links 40a and 40b swing. It is supported by the device mounting base 30 in this state.
Of the sleeves 41a and 41b with a brim, the sleeve 41b with a brim on the right side has a thread trimming device 4 with the sleeve 41a with a brim on the left link 40a as a fulcrum by changing the pitch of the holes at both ends of the link 40b on the right side. The position of the needle drop portion of the movable female 5 at the advance position P1 and the position of the advance movement starting point in the sewing progress direction with respect to the looper 3 are formed in an executor shape so as to be finely adjustable.

The fixed female base 29 is formed with a contact member 34 that abuts on the stopper member 33 screwed to the device mounting base 30 at a position below the left link 40a of the pair of left and right links 40a and 40b.

Further, an engaging protrusion 36 is formed at the rear portion of the central portion of the fixed female base 29 in the longitudinal direction so as to abut and separate from the protrusion 35 protruding rearward from a position slightly to the right of the left end of the movable female base 24. The movable female base 24 is configured so that the movable female base 24 cannot move further to the right by itself when the engaging protrusion 36 comes into contact with the protrusion 35. Further, the movable female base 24 is always leftward together with the fixed female base 29 via a spring 37 which is screwed to the device mounting base 30 and whose one end is elastically contacted with the right end surface of the contact member 34. It is elastically urged to.

The device mounting base 30 is formed with a groove 46 into which the fixing female base 29 is slidably fitted in the left-right direction, and is fixed to the sewing machine bed portion 22 via a plurality of screws 47 arranged around the device mounting base 30. ing. Further, the device mounting base 30 is pivotally connected to the tip of a piston 48 of an air cylinder (not shown) via a stepped screw 43, and is pivotally connected to the device mounting base 30 in the direction of arrows ab about the shaft 44. A drive lever 45 that can be driven and swung is attached to, and a tapered circular portion 45a at the tip of the drive lever 45 is engaged with a U-shaped notch 25 formed in a substantially central portion of the movable female base 24. ing.

According to the reciprocating drive moving mechanism 9 configured as described above, as shown in FIGS. 3A and 3B, when the drive lever 45 is driven and swung in the b direction due to the extension of the piston 48, In the thread trimming device 4, since the contact member 34 of the fixed female base 29 is elastically urged to the left by the spring 37, the movable female base 24 moves to the right and comes into contact with the engaging protrusion 36. Further, it moved to the right against the elastic urging force of the spring 37, and the columnar nuts 31a and 31b of the pair of left and right links 40 and 41 moved closer to the leftmost side of the pair of left and right slits 26a and 26b. Moving to the state, the left end surface of the contact member 34 of the fixed female base 29 is separated from the stopper member 33. In this state, the thread trimming device 4 is in the retracted position P2 and stands by in an inclined posture so as not to hinder the movement of the looper 3.

Next, as shown in FIGS. 4A and 4B, when the drive lever 45 is driven and swung in the a direction due to the contraction of the piston 48, the contact member 34 of the fixed female base 29 is elastic of the spring 37. Move to the left in combination with the urging force. Along with this, the thread trimming device 4 reduces the tilt angle of the tilted posture by swinging the pair of left and right links 40, 41 while the engaging protrusion 36 and the protrusion 35 are in contact with each other, and the fixed female base 29 It moves to the left until the left end surface of the hit member 34 comes into contact with the stopper member 33. As a result, the thread trimming device 4 moves to the advance position P1 and takes a posture substantially orthogonal to the sewing traveling direction.

When the piston 48 further contracts from this state and the drive lever 45 is driven and swung in the a direction, the engaging projection 36 of the fixed female base 29 remains at the advance position P1 while the fixed female base 29 remains at the advance position P1. And the protrusion 35 of the movable female base 24 are separated from each other, and the movable female base 24 passes through the needle drop position of the needle plate 2 and moves in the left direction (x direction). That is, only the movable scalpel 5 fixed to the movable scalpel base 24 moves leftward (forward movement) between the needle plate 3 and the looper 3. At this time, the movable female base 24 and the fixed female base 29 are supported by the device mounting base 30 in a state where they can reciprocate in the left-right direction as the pair of left and right links 40a and 40b swing. The female 5 is controlled so as to be linearly moved by a pair of left and right links 40 and 41.

Next, when the piston 48 is extended, the drive lever 45 is driven and swung in the b direction, and accordingly, the movable female 5 moves to the right (y direction) from the position where the movable female 5 is most leftward. Retreat to the lower part of the fixed female 6 waiting at the advance position P1 (go-around movement). As the piston 48 further contracts from this state, the thread trimming device 4 is moved backward to the retracted position P2 shown in FIGS. 3A and 3B.

In addition to the configuration and the apparatus described above, the double chain sewing machine M of the present embodiment includes an air ejection nozzle 50 arranged at a position on the upper side of the sewing traveling direction H of the looper 3 and the looper 3. The opening / closing thread pinching mechanism 60 arranged at a position facing the air ejection nozzle 50 on the lower side of the sewing progress direction H, and the air ejection nozzle 50 and the opening / closing thread above the advance / retreat operation path of the looper 3. The looper thread guide member 70 arranged between the pinching mechanism 60 and the looper 3 are arranged at a position closer to the retracting side of the looper 3 than the opening / closing type thread pinching mechanism 60 on the lower side of the sewing progress direction H of the looper 3. The looper thread holding member 80 and a control means for controlling the opening / closing operation of the opening / closing type thread pinching mechanism 60 are provided.

Among the above components, the air ejection nozzle 50, the opening / closing type thread pinching mechanism 60, the looper thread guide member 70, and the looper thread holding member 80 are each housed and arranged inside the sewing machine bed portion 22. However, in order to avoid complication due to overlap between these components and each component of the reciprocating drive moving mechanism 9 described above, the description of each of these components in FIGS. 1 and 2 is omitted. The control means is incorporated in a control unit (not shown) for controlling the operation of the entire double chain sewing machine.

The air ejection nozzle 50 is cut by the thread trimming device 4 when the looper 3 is located at a substantially advanced end after sewing is completed, and as shown in FIG. 11, the thread hole at the tip of the looper 3 is cut. As shown in FIG. 12, by ejecting air toward the cut end portion LT2 of the looper thread portion LT1 which is connected to 3a and hangs down in a free state (referred to as the looper thread cut end portion LT2 in the following description). The looper thread portion cut end portion LT2 is blown off toward the lower side of the sewing progress direction H of the looper 3 through the upper portion of the looper 3 and functions as a looper thread transfer means.

The opening / closing type thread pinching mechanism 60 is configured to be openable / closable by a fixed pinching piece 61 and a slider piece 62 that moves in perspective with respect to the fixed pinching piece 61 via an air cylinder (not shown), and is configured from the nozzle 50. As shown in FIG. 13, the fixed sandwich piece 61 and the slider piece are located near the tip of the looper thread cutting end portion LT2 which is blown away to the lower side of the sewing progress direction H of the looper 3 by the ejected air. A looper that is temporarily pinched and held by the closing operation with the 62, and is released from the pinching and holding near the tip of the looper thread cutting end portion LT2 by the opening operation of the fixed pinching piece 61 and the slider piece 62. It functions as a temporary thread pinch holding means.

As the looper thread temporary pinching and holding means, the looper thread cutting end portion LT2 is forcibly pinched and held and pinched by the opening and closing operation of the fixed pinching piece 61 and the slide piece 62 as in the above-mentioned opening and closing type thread pinching mechanism 60. The looper thread cutting end portion LT2 is sandwiched and held by an elastic force such as a spring by the fixed sandwich piece 61 and the slide piece 62, and the looper thread cutting end portion LT2 is next. It also includes a material configured to be pulled out of the pinching holding position and released from the pinching holding position against the elastic force of the spring or the like when the seam of the sewing start portion of the fabric is pulled.

As shown in FIG. 12, the looper thread guide member 70 moves the looper thread cutting end portion TL2 blown over the upper portion of the looper 3 by the air ejected from the nozzle 60 in the substantially sewing progress direction H. It has a passage 71 through which the thread is passed while being corrected to a substantially horizontal posture along the line. The upper surface plate portion 72 of the passage 71 in the looper thread guide member 70 can visually confirm whether or not the looper thread cutting end portion LT2 has passed through the passage 71 and has been corrected to a substantially horizontal posture along the substantially sewing direction H. It is formed in a transparent window like this. Further, when the intermediate portion LT2a of the looper thread cutting end portion LT2 is guided toward the looper thread holding member 80 on the right wall portion 74 of the passage 71 in the looper thread guide member 70, the opening / closing type thread pinching mechanism. A looper thread slide groove 73 is formed to guide the portion near the tip portion sandwiched and held by the 60 to the lower side in the sewing traveling direction H {see FIGS. 14 (B) to 17 (B)}.

The looper thread holding member 80 reaches the tip of the opening / closing thread pinching mechanism 60 by operating the needles 1a, 1b and the looper 3 half a turn to form an empty ring or to form a stitch on the next fabric. As shown in FIGS. 15A and 16A, the intermediate portion LT2a of the looper thread cutting end portion LT2 whose vicinity of the portion is sandwiched and held is extended to a substantially central position between the left and right needles 1a and 1b. The looper thread guiding portion 81 to be guided and the intermediate portion LT2a of the looper thread cutting end portion LT2 guided by the guiding portion 81 to a substantially central position between the left and right needles 1a and 1b are shown in FIGS. 16 to 19. As shown, it has a looper thread holding groove portion 82 that holds the looper thread holding groove portion 82 in a state in which the pull-out movement in a direction other than the sewing progress direction H is prevented.

More specifically, the looper thread holding member 80 is entirely composed of a substantially lateral V-shaped plate-shaped member when viewed from the sewing progress direction H, and the V-shaped open portion is a looper thread midway portion. It is formed on the receiving guide portion 83 of the LT2a. The looper thread guiding portion 81 is formed from an inclined edge that is located at the highest position on the advanced end side of the looper 3 along the upper side of the receiving guide portion 83 and is gradually lowered toward the entrance of the looper thread holding groove portion 82. The looper thread holding groove portion 82 is guided to a substantially central position between the left and right needles 1a and 1b in a state where the intermediate portion LT2a of the looper thread cutting end portion LT2 is in sliding contact with the guide portion 81 formed of the inclined edge thereof. It is configured to be dropped and held in.

The looper thread holding member 80 is one of a pair of front and rear needle receivers (not shown) provided in the sewing bed portion 22 in the sewing progress direction H so as to prevent the left and right needles 1a and 1b from wobbling. It is fixed to the needle holder 90 on the front (lower) side of the sewing progress direction H, and the looper thread holding groove portion 82 of the looper thread holding member 80 holds the middle portion LT2a of the looper thread cutting end portion LT2. When the needles 1a, 1b and the looper 3 are operated substantially one turn via the control means, the pinching holding by the opening / closing type thread pinching mechanism 60 is released, and then double chain stitching is performed on the next fabric portion. By controlling so as to form the seam A, the tip (thread end) of the looper thread cutting end portion LT2 stays at a position within the substantially width of the seam A of the double chain stitch of the next fabric portion. It is configured to be processed into states.

Next, the hem pull stitch of the round cloth W such as the hem of the T-shirt is performed by using the two-needle type horizontal tubular double chain stitch sewing machine M according to the present embodiment configured as described above. The sewing operation will be described with reference to FIGS. 10 to 20.

First, as shown in FIG. 10, at the hem of the round fabric W, the overlapped fabric portion in which the edge portion of the fabric is folded back to the back side of the fabric and overlapped is set on the needle plate 2, and then the round fabric is set. The overlapped fabric portion of W is fed and guided in the predetermined sewing traveling direction H, and the rotation operation of the sewing machine M is started. By the ascending / descending operation of the left and right needles 1a and 1b, the advancing / retreating operation of the looper 3, and the feeding action of the round cloth W accompanying the rotational operation of the sewing machine M, the same steps as shown in FIGS. Then, hemming stitching is performed to form a double chain stitch stitch A on the entire circumference of the overlapped fabric portion of the round fabric W.

After the sewing (hem pulling sewing) is completed, the needle thread portions NTa1, NTb1 and the looper thread portion LT1 are cut by the thread trimming device 4. At this time, since the cutting position is a position away from the needle drop position so as not to enter the vertical reciprocating path of the needles 1a and 1b, and is an external position on the right side of the right needle 1b, after cutting. The left and right needle thread portions NTa1 and NTb1 and the cut end portion LT2 of the looper thread portion LT1 have a predetermined remaining thread length.

After the above cutting, the left and right needle thread portions NTa1 and NTb1 that have been cut are lifted upward within the width of the stitch A, and a stitch A is formed at the sewing start portion of the next fabric with an appropriate remaining thread length. .. On the other hand, the looper thread cutting end portion LT2 that has been cut and remains at a predetermined length will protrude largely like a whiskers to the outside of the seam A as it is. Therefore, in order to treat the looper thread cutting end portion LT2 as a short thread remaining length so as to be visually fastened at a position within the substantially width of the double chain stitch formed at the sewing start portion of the next fabric. The step operation as described below is performed.

First step: First, the cut looper thread cutting end portion LT2 is separated from the needle drop position at the tip portion and further to the right outside position than the right needle 1b, as in the conventional case, and the movable knife 5 and the looper thread pinching member. As shown in FIG. 11, it is separated from the position of the left needle 1a to the left as a free state connected to the thread hole 3a at the tip of the looper 3 located at the substantially advanced end without being sandwiched and held between the two. Let it hang down at the vertical position.

Second step: Next, with the fixed pinching piece 61 and the slider piece 62 of the opening / closing type thread pinching mechanism 60 being opened, air is blown from the air ejection nozzle 50 toward the looper thread cutting end portion LT2. By ejecting, as shown in FIG. 12, the looper thread cutting end portion LT2 is blown off and shifted toward the lower side of the sewing progress direction H of the looper 3 through the upper portion of the looper 3. At this time, the looper thread cutting end portion TL2 blown over the upper portion of the looper 3 by the air ejected from the nozzle 50 is guided to the passage 71 of the looper thread guide member 70 and passed through the passage 71. The looper thread cutting end portion LT2 is corrected to a substantially horizontal posture along the substantially sewing traveling direction H.

Third step: Subsequently, at the same time as stopping the air ejection from the nozzle 50, the slider piece 62 of the opening / closing type thread pinching mechanism 60 is slid toward the fixed piece 61 to close both pieces 62 and 61. , As shown in FIGS. 13 and 14, the vicinity of the tip end portion of the looper thread cutting end portion LT2 is sandwiched and held.

Fourth step: In this state, the needles 1a and 1b and the looper 3 are operated half a turn with the operation of the sewing machine M in order to form an air ring or a stitch on the next fabric. As shown in A), the middle portion LT2a of the looper thread LT1 whose tip portion is sandwiched and held by the opening / closing type thread pinching mechanism 60 is the receiving guide portion 83 of the looper thread holding member 80 as the looper 3 moves backward. After being accepted by the user, the needle is guided toward a substantially central position between the left and right needles 1a and 1b in a state of being slidably contacted with the guide portion 81 having an inclined edge. At the same time, as shown in FIG. 15B, the portion in the vicinity of the tip portion sandwiched and held by the opening / closing type thread pinching mechanism 60 faces the lower side of the looper thread slide groove 73 in the sewing progress direction H. You will be guided by a slide. As a result of this state continuing, the looper thread midway portion LT2 guided to a substantially central position between the left and right needles 1a and 1b is dropped and held in the looper thread holding groove portion 82 as shown in FIG. 16 (A). At the same time, as shown in FIG. 16B, the portion near the tip portion sandwiched and held by the opening / closing type thread pinching mechanism 60 is the innermost end portion (in the sewing progress direction H) in the looper thread slide groove 73. Moved to the bottom).

Fifth step: Subsequently, the left and right needles 1a and 1b and the looper 3 are rotated by the operation of the sewing machine M, and when the looper 3 reaches the vicinity of the needle drop (near the middle portion between the left and right needles 1a and 1b), As shown in FIG. 17, the looper 3 advances the rear side of the needles 1a and 1b while pushing up the looper thread portion near the thread hole 3a at the tip of the looper 3. Then, the left and right needles 1a and 1b and the looper 3 rotate due to the subsequent operation of the sewing machine M, and the looper 3 retreats from a position near the advance end before reaching the advance end by rotating approximately half a turn after reversing at the advance end. As shown in FIG. 18, the slider piece 62 of the opening / closing type thread pinching mechanism 60 is slid to the side away from the fixed piece 61 at the set operation position until the position near the entrance end is reached, and both pieces 62 and 61 are moved. By opening the looper thread, the pinching and holding near the tip of the looper thread cutting end portion LT2 is released.

In the fifth and subsequent steps, the left and right needles 1a and 1b and the looper 3 are rotated to perform a predetermined sewing for forming the double chain stitch A on the next fabric. Since the cut end portion LT2 is released from being pinched and held before the predetermined sewing operation, the looper thread cut end portion LT2 is used as the looper thread having a stitch structure at the start of sewing, and thus its length. That is, the remaining thread of the looper thread becomes shorter. Further, the looper thread cutting end portion LT2 is in a free state when the intermediate portion LT2a passes through the looper thread holding groove portion 82 of the looper thread holding member 80 and is in a free state, and after the sewing operation of the first stitch, the short looper thread is formed. The thread end LTE of the cut end portion LT2 is located within the width of the stitch A at the sewing start portion, for example, as shown in FIG.

After that, the predetermined sewing of the next fabric is continued, and even after the second stitch and the subsequent sewing operations, the short looper thread cutting end portion LTE2 starts sewing at the thread end LTE, for example, as shown in FIG. It remains positioned within the width of the seam A at the location.

The double chain stitch A, which has been sewn to the next fabric by the operations of the first step to the fifth step and the fifth and subsequent steps, has a structural form as shown in FIGS. 6 to 9. In any of the structural forms of the stitch A shown in FIGS. 6 to 9, the length of the looper thread cutting end portion LTE2, that is, the remaining thread of the looper thread is short, so that the thread end LTE is the stitch A. It does not protrude significantly to either the left or right side of.

When the stitch A of the structural form shown in FIGS. 6 to 9 is observed in detail, the thread end LTE of the looper thread cutting end portion LT2 is the right or left needle thread portion as shown in FIGS. 7 and 8. Although it may protrude to the outside, the amount of protrusion is very small, and the looper thread cutting end part LTE2 protrudes greatly toward the outside of the left and right needle thread parts, or rises from the fabric surface. As a result, it can be processed to the extent that the appearance does not deteriorate visually.

In particular, in the fifth and subsequent steps, among the predetermined sewing performed with the looper thread cutting end portion LT2 in the free state, the feed amount of the fabric W of at least one to three stitches at the start of sewing is usually set thereafter. By setting it smaller than the feed amount of the fabric at the time of sewing, the pitch of the left and right needle thread portions becomes smaller, and the looper thread cutting end portion LT2 is pressed by the looper thread or needle thread that forms the stitch A of the next fabric. Therefore, it is possible to prevent the thread end LTE of the looper thread from protruding to the left and right of the needle thread portion, and to further improve the appearance.

As described above, the remaining length of the looper thread cutting end portion LT2 cut by the thread trimming device 4 can be shortened as much as possible, and the thread end can be kept at a position within the substantially width of the stitch A. Even when a looper thread of a type that can be separated into a plurality of ultrafine fiments by cutting is used as the looper thread, the tip (thread end) of the looper thread cut end portion LT2 including the plurality of ultrafine filaments is separated. It is possible to prevent the appearance from being deteriorated due to a large protrusion to the outside of the seam A or rising from the surface of the fabric, resulting in poor finish.

Therefore, it is necessary for the sewing maker to perform a troublesome and time-consuming manual work of cutting the cut end portion LT2 of the looper thread short by using, for example, hand scissors, after the sewing is completed or before the sewing of the next fabric is started. The operability of the fabric is also improved because the sewing work efficiency can be improved by that amount, the work load on the sewing maker can be reduced, and the degree of freedom of the sewing maker's hands is increased. The sewn finish can be improved, and the sewn fabric W is not damaged by hand scissors or the like, so that the appearance and quality of the sewn product can be improved.

In particular, when the hem pull stitch is performed on the round fabric W as the sewing target as in the present embodiment, the sewing start portion and the sewing end portion are sewn slightly in layers. At this time, the first stitch at the start of sewing is performed. It is possible to keep the looper thread cutting end portion LT2 protruding like a whiskers on the back surface of the fabric W at a position within the substantially width of the stitch A of the sewing start portion of the next fabric by the operations of the first to fifth steps and thereafter. Therefore, it is not necessary to temporarily interrupt the sewing operation in the middle of sewing, hold a pair of scissors or the like to manually perform a short cutting process, and then restart the sewing operation to perform lap stitching. Therefore, it is possible to continuously perform hemming stitching on the entire circumference of the round fabric W including the lap stitching at the end of sewing, eliminating the time loss for processing the long remaining looper thread cutting end portion LT2. It is possible to further improve the sewing work efficiency, and it is possible to obtain a good appearance and a good-looking finish.

In the above embodiment, an air ejection nozzle that is structurally simple and does not take up space is used as a transition means for shifting the looper thread cutting end portion LT2 to the lower side of the sewing progress direction H of the looper 3. Not limited to this, a holding tool for holding the looper thread cutting end portion LT2 is provided, and the looper thread cutting end portion LT2 is moved by moving this holding tool to the lower side of the sewing progress direction H of the looper 3. You may.

Further, as an operation position in which both pieces 62 and 61 of the opening / closing type thread pinching mechanism 60 are opened to release the pinching holding near the tip end portion of the looper thread cutting end portion LT2, the looper 3 reaches the advanced end. It may be set anywhere from the position near the advancing end to the position near the advancing end after reversing at the advancing end and reaching the position near the retreating end. It is possible to shorten the remaining thread of the looper thread by setting it to the position of.

Further, in the above embodiment, the looper thread holding member 80 is composed of a plate-shaped member having a substantially lateral V-shape when viewed from the sewing progress direction H, and the V-shaped open portion is in the middle of the looper thread. Along with being formed in the receiving guide portion 83 of the partial LT2a. The guide portion 81 is formed from an inclined edge in which the advancing end side of the looper 3 is located at the highest position along the upper side of the receiving guide portion 83 and is gradually lowered toward the entrance of the looper thread holding groove portion 82. However, in addition to this, a looper having an inclined edge having a reverse slope, that is, an inclined edge formed from an inclined edge in which the advanced end side of the looper 3 is located at the lowest position and is gradually higher toward the entrance of the looper thread holding groove portion 82. Any shape of plate-shaped member may be used as long as it has an inclined edge capable of guiding and guiding the intermediate portion LT2a of the thread cutting portion LT2 between the left and right needles, and the inclined edge (induction portion) 81. The looper thread holding groove portion 82 may be formed of a wire rod.

Further, in the above-described embodiment, the application is applied to a two-needle type horizontal tubular double-ring sewing machine, but the present invention is not limited to this, and may be applied to a two-needle type flatbed type double-ring sewing machine. It may be applied to a multi-needle type horizontal cylinder type or flat bed type double chain sewing machine having three or more needles. However, in the case of a multi-needle type sewing machine having three or more needles, it is preferable to guide and hold the middle portion LT2a of the looper thread cutting end portion LT2 among the plurality of needles between the needles at both ends in the parallel direction. It is preferable to guide and hold the needle at a substantially central position in the parallel direction. When applied to any type of sewing machine, the same effect as that of the above-described embodiment can be obtained.

1a, 1b Needle 2 Needle plate 3 Looper 3a Tip thread hole 4 Thread trimmer 50 Air ejection muzzle (Transfer means for looper thread cutting end)
60 Retractable thread pinching mechanism (looper thread holding means)
70 Looper thread guide member 71 Passage 80 Looper thread holding member 81 Inclined edge (looper thread guide part)
82 Looper thread holding groove NTa, NTb Needle thread LT Looper thread LT1 Protruding and cutting looper thread part LT2 Looper thread cutting end part LT2a Looper thread Midway part LTe Looper thread thread end M Double chain sewing machine W Sewing fabric (round) Cloth)
A Double chain stitch H Sewing direction

Claims (13)

While feeding the fabric along the upper surface of the needle plate in a predetermined sewing progress direction, a plurality of needle thread loops are moved under the needle plate by the vertical movement of a plurality of needles arranged in parallel in a direction substantially orthogonal to the sewing progress direction. The plurality of needle threads are formed by advancing and retreating a looper capable of advancing and retreating in a direction substantially orthogonal to the sewing progress direction between one side portion and the other side portion in the parallel direction of the plurality of needles. A method of sewing a fabric in which a loop is captured and a plurality of needle thread loops captured are looped by a looper yarn held by the looper to form a double chain stitch of a plurality of needles on the fabric.
When the looper is located at the substantially advanced end after the sewing is completed, the looper thread is cut by the thread trimming device arranged on the other side in the parallel direction of the needle and connected to the thread hole at the tip of the looper. The first step to free the ends and
The second step of shifting the cut end portion of the looper thread in the free state toward the lower side in the sewing progress direction of the looper so as to be in a posture along the substantially sewing progress direction.
The third step of holding the vicinity of the tip of the cut end portion of the looper thread shifted to the lower side in the sewing progress direction, and
By operating the needle and the looper at least half a turn to form an air ring or to form a stitch on the next fabric, the plurality of needles in the middle portion of the looper yarn held near the tip portion. Of these, a state in which the needles are guided to a set position within the range connecting the neighboring portions of the needles at both ends in the parallel direction, and the movement of the intermediate portion of the looper thread is blocked from the guided set position except in the sewing progress direction. And the 4th step to hold
Among the rotational movements of the needle and the looper following the fourth step, the needle is near the top dead center and the looper is near the advanced end, the needle is near the bottom dead center and the looper is near the retracted end. In the set operation position within the rotation operation range until the position is reached, the fifth step of releasing the holding of the cut end portion of the looper thread with respect to the vicinity of the tip portion, and
Have,
From the fifth step onward, a method for sewing a fabric, which comprises performing a predetermined sewing while leaving the cut end portion of the looper thread in a free state. Of the predetermined sewing performed with the cut end portion of the looper thread in the free state in the fifth and subsequent steps, the feed amount of the fabric at the sewing start portion is set to be smaller than the feed amount of the fabric at the time of normal sewing. The method for sewing a fabric according to claim 1, wherein the fabric is sewn. In the fourth step, the middle portion of the looper thread held near the tip portion is guided to a position between the needles at both ends in the parallel direction among the plurality of needles, and the guided position is used as the guide. The method for sewing a fabric according to claim 1, wherein the movement of the intermediate portion of the looper thread is held in a state of being blocked except in the sewing traveling direction. The overlapped fabric portion in which the edge portion of the round fabric is folded back and overlapped on the back surface side of the fabric is fed in the predetermined sewing progress direction along the upper surface of the needle plate and parallel to the direction substantially orthogonal to the sewing progress direction. A plurality of needle thread loops are formed under the needle plate by the vertical movement of the plurality of arranged needles, and the sewing is performed between one side portion and the other side portion in the parallel direction of the plurality of needles. The plurality of needle thread loops are captured by the advance of a looper capable of advancing and retreating in a direction substantially orthogonal to the traveling direction, and the captured plurality of needle thread loops are looped by the looper thread held by the looper to form the round object. Overlapping of fabrics This is a method of sewing fabrics that forms double-chain stitches all around the fabric part.
When the looper is located at the substantially advanced end after the sewing is completed, the looper thread is cut by the thread trimming device arranged on the other side in the parallel direction of the needle and connected to the thread hole at the tip of the looper. The first step to free the ends and
The second step of shifting the cut end portion of the looper thread in the free state toward the lower side in the sewing progress direction of the looper so as to be in a posture along the substantially sewing progress direction.
The third step of holding the vicinity of the tip of the cut end portion of the looper thread shifted to the lower side in the sewing progress direction, and
By operating the needle and the looper at least half a turn to form an air ring or to form a stitch on the next fabric, the plurality of needles in the middle portion of the looper yarn held near the tip portion. Of these, a state in which the needles are guided to a set position within the range connecting the neighboring portions of the needles at both ends in the parallel direction, and the movement of the intermediate portion of the looper thread is blocked from the guided set position except in the sewing progress direction. And the 4th step to hold
Among the rotational movements of the needle and the looper following the fourth step, the needle is near the top dead center and the looper is near the advanced end, the needle is near the bottom dead center and the looper is near the retracted end. In the set operation position within the rotation operation range until the position is reached, the fifth step of releasing the holding of the cut end portion of the looper thread with respect to the vicinity of the tip portion, and
Have,
The fifth and subsequent steps are a method for sewing a fabric, which comprises performing predetermined sewing while leaving the cut end portion of the looper thread in a free state. Of the predetermined sewing performed with the cut end portion of the looper thread in the free state in the fifth and subsequent steps, the feed amount of the fabric at the sewing start portion is set to be smaller than the feed amount of the fabric at the time of normal sewing. The method for sewing a fabric according to claim 4, wherein the fabric is sewn. In the fourth step, the middle portion of the looper thread held near the tip portion is guided to a position between the needles at both ends in the parallel direction among the plurality of needles, and the guided position is used as the guide. The method for sewing a fabric according to claim 4, wherein the movement of the intermediate portion of the looper thread is held in a state of being blocked except in the sewing traveling direction. A needle plate that sets the fabric and guides the feed in the predetermined sewing progress direction, a plurality of needles that are arranged in parallel in a direction substantially orthogonal to the sewing progress direction, hold the needle thread, and move up and down, and a looper thread. It can be held and moved forward and backward in a direction substantially orthogonal to the sewing progress direction between one side portion and the other side portion in the parallel direction of the plurality of needles, and the needles are placed under the needle plate during the advancement operation. It is equipped with a looper that captures a plurality of needle thread loops to be formed, and a thread trimming device that is arranged on the other side of the needle in the parallel direction and cuts the looper thread and the needle thread after sewing, and is captured by the advance operation of the looper. A double chain stitch sewing machine configured to form a double chain stitch on the fabric by looping the plurality of needle thread loops with the looper thread held by the looper.
When the looper is located at a substantially advanced end after sewing is completed, the cut end portion of the looper thread that has been cut by the thread trimming device and connected to the thread hole at the tip of the looper to be in a free state is attached to the looper. A means of shifting the cut end portion of the looper thread, which shifts the looper thread so as to be in a posture along the substantially sewing progress direction toward the lower side in the sewing progress direction, and
A looper thread holding means capable of holding and releasing the vicinity of the tip of the cut end portion of the looper thread shifted to the lower side in the sewing progress direction, and
By operating the needle and the looper at least half a turn to form an air ring or to form a seam on the next fabric, the plurality of needles in the middle portion of the looper yarn held near the tip portion. Of these, the looper thread guiding portion that guides the looper thread to the set position within the range connecting the neighboring portions of the needles at both ends in the parallel direction and the intermediate portion of the looper thread that is guided to the set position by this guiding portion are pulled out. A looper thread holding member having a looper thread holding groove portion that holds the looper thread holding groove portion in a state of being blocked except in the sewing progress direction,
With the middle portion of the looper thread held by the looper thread holding member, the needle and the looper are rotated to move the needle down from a position where the needle is near top dead center and the looper is near the advanced end. A control means for controlling to release the holding by the looper thread holding means at a set operation position within the rotation operation range until the looper reaches a position near the dead center and the retracting end.
With
A double-ring sewing machine characterized in that after the control operation of the control means, a predetermined sewing is performed on the next fabric while the cut end portion of the looper thread is left in a free state. The transfer means of the cut end portion of the looper yarn is an air ejection nozzle, and the looper yarn blown off by the air ejected from the air ejection nozzle is cut between the air ejection nozzle and the looper yarn holding means. The double chain sewing machine according to claim 7, further comprising a looper thread guide member having a passage through which the end portion is corrected to a substantially horizontal posture along a substantially horizontal sewing traveling direction. The seventh aspect of claim 7, wherein the looper thread holding member is arranged so that the looper thread guiding portion is positioned between the needles at both ends in the parallel direction among the plurality of needles. Double chain stitch sewing machine. The edge of the round fabric is folded back to the back side of the fabric, and the overlapped fabric portion is set and the needle plate guides the feed in the predetermined sewing progress direction, in a direction substantially orthogonal to the sewing progress direction. The sewing progress direction extends between a plurality of needles arranged in parallel and holding the needle threads to move up and down, and between one side portion and the other side portion of the plurality of needles in the parallel direction while holding the looper thread. A looper that can move forward and backward in a direction substantially orthogonal to the needle plate, and a looper that catches a plurality of needle thread loops formed under the needle plate during the advance movement, and a looper that is placed on the other side of the needle in the parallel direction and after sewing. A thread trimming device for cutting the thread and the needle thread is provided, and the plurality of needle thread loops captured by the advance operation of the looper are looped with the looper thread held by the looper to superimpose the round fabric. A double chain stitch sewing machine for sewing round fabrics, which is configured to form double chain stitches on the entire circumference of the fabric portion.
When the looper is located at a substantially advanced end after sewing is completed, the cut end portion of the looper thread that has been cut by the thread trimming device and connected to the thread hole at the tip of the looper to be in a free state is attached to the looper. A means of shifting the cut end portion of the looper thread, which shifts the looper thread so as to be in a posture along the substantially sewing progress direction toward the lower side in the sewing progress direction, and
A looper thread holding means capable of holding and releasing the vicinity of the tip of the cut end portion of the looper thread shifted to the lower side in the sewing progress direction, and
By operating the needle and the looper at least half a turn to form an air ring or to form a seam on the next fabric, the plurality of needles in the middle portion of the looper yarn held near the tip portion. Of these, the looper thread guiding portion that guides the looper thread to the set position within the range connecting the neighboring portions of the needles at both ends in the parallel direction and the intermediate portion of the looper thread that is guided to the set position by this guiding portion are pulled out. A looper thread holding member having a looper thread holding groove portion that holds the looper thread holding groove portion in a state of being blocked except in the sewing progress direction,
With the middle portion of the looper thread held by the looper thread holding member, the needle and the looper are rotated to move the needle down from a position where the needle is near top dead center and the looper is near the advanced end. A control means for controlling to release the holding by the looper thread holding means at a set operation position within the rotation operation range until the looper reaches a position near the dead center and the retracting end.
With
After the control operation of the control means, a double for sewing a round fabric, characterized in that a predetermined sewing is performed on the next fabric while the cut end portion of the looper thread is left in a free state. Chain stitch sewing machine. The transfer means of the cut end portion of the looper yarn is an air ejection nozzle, and the looper yarn blown off by the air ejected from the air ejection nozzle is cut between the air ejection nozzle and the looper yarn holding means. The double ring for sewing a round fabric according to claim 10, wherein a looper thread guide member having a passage through which the end portion is corrected to a substantially horizontal posture along a substantially horizontal sewing progress direction is provided. Sewing machine. The tenth aspect of the present invention, wherein the looper thread holding member is arranged so that the looper thread guiding portion is arranged at a position between the needles at both ends in the parallel direction among the plurality of needles. Double chain stitch sewing machine. The double-ring sewing machine according to claim 7 or 10, wherein the target sewing machine is a two-needle type horizontal tubular double-ring sewing machine.

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