JP5522577B2 - Double chainstitch sewing machine with seams - Google Patents

Description

  The present invention is a sewing machine typified by a horizontal cylindrical double chain stitch sewing machine, in which a double chain stitch is formed by a needle thread and a looper thread, and the seam of the double chain stitch is formed. The present invention relates to a double chain stitch sewing machine with a fray prevention device for preventing fraying at the end portion.

  A double chainstitch sewing machine, such as a horizontal cylinder, moves forward and backward in a direction substantially perpendicular to the vertical movement path of the needle holding one or more needles holding and holding the needle thread and a looper thread A sewing thread by capturing a needle thread loop formed by the needle below the needle plate by an advance operation of the looper, and looping the needle thread with the looper thread held by the looper. This is a sewing machine which forms double chain stitches.

  As shown in FIG. 20, a common double chain stitch seam formed by a double chain stitch sewing machine has an end portion of the looper thread 10 cut at the end of sewing as indicated by an arrow in FIG. When pulled in the direction, the looper thread 10 slips out from the final needle thread loops 20a, 20b formed by the needle threads 20, 20, and the slipping out easily propagates toward the sewing start side. There is a problem that fraying occurs in the entire eye.

  Such fraying also occurs in the stitches of double chain stitches formed by one needle thread or two or more needle threads and a looper thread.

  For the purpose of preventing fraying peculiar to the stitches formed by the double chain stitch sewing machine as described above, the applicant of the present application is provided with a fraying prevention device as shown in Japanese Patent Application Nos. 2011-016821 and 2011-115174. A double chain stitch sewing machine has been developed and a patent application has already been filed (hereinafter referred to as a patent application technology by the present applicant).

  As shown in FIGS. 21 to 23, a fraying prevention device for a seam of a double chain stitch sewing machine (here, a two-needle sewing machine) of the patent application already filed by the present applicant is used. , 20 and needles 2 and 2 (see FIGS. 11 to 17) that move up and down with respect to the needle drop positions A and A that are set at substantially the center of the needle plate P and spaced in the left-right direction, and a looper. A looper 1 that holds the thread 10 and is capable of moving back and forth in the direction in which the needle drop positions A and A are aligned, and that captures the needle thread loops 20a and 20b formed below the needle plate P when advanced (see FIGS. 11 to 17) 21, and can move toward and away from the looper 1. As shown in FIG. 21, it extends between a standby position away from the looper 1 and a yarn hooking position approaching the looper 1 as shown in FIG. 23. A thread hook that swings in a plane substantially parallel to the needle plate P about the vertical support shaft 30. A thread operation air cylinder (hereinafter referred to as a thread operation cylinder) 32 as a hook actuator for driving and swinging the hook 3 and the thread hook 3 to the standby position and the thread hook position, and a thread hook 3, the needle thread loops 20a and 20b, which are disposed at a position farther from the needle plate P than 3 and captured by the thread hook 3 at the thread hook position, are held at a holding position between the thread hook position and the standby position. The swing lever 9 and the stopper lever 4 that swing about the vertical support shaft 90 in a plane substantially parallel to the needle plate P, and the engagement that engages the stopper lever 4 with a part of the swing lever 9. A stopper air cylinder (hereinafter referred to as a stopper cylinder) 42 as a stopper actuator for driving and swinging from a position to a retracted position deviated from the engagement position, and swinging with the thread hook 3. One of the connecting rod 35 that interlocks the bar 9 and the thread operating cylinder 32 and the stopper cylinder 42 are selectively controlled after normal sewing is finished, and the thread hook 3 is caught at the thread hook position. A control unit 8 (see FIG. 8) is configured to hold the needle thread loop 20b at the holding position, and to perform a sewing operation for at least one stitch while maintaining this state.

  In addition, in the anti-fraying device for the double chain stitch sewing machine of the already-applied patent application by the present applicant, the same or corresponding constituent members and constituent parts in the anti-fraying device described as an embodiment of the present invention described later and The constituent parts are denoted by the same reference numerals as those used in the embodiment of the present invention, and detailed description thereof will be omitted.

  According to the above-mentioned patent application technology by the present applicant, after normal sewing is finished, the operations of the thread hook 3, the stopper lever 4 and the swing lever 9 are controlled via the control unit as described above. By performing the sewing operation for one stitch, as shown in FIG. 18, the looper thread 10 is formed on the right side (the left side in FIG. 18) formed on the back surface of the sewing fabric at the end of the stitch M of the double chain stitch. ) In the final needle thread loop 20a, folded back in front of the needle thread 20 that slips out to the back of the sewing fabric when sewing for one stitch to prevent fraying, and passes through the right final needle thread loop 20a. Disconnected. On the other hand, the needle thread 20 on the left side (right side in FIG. 18) that slips out to the back surface of the sewing fabric when sewing for one stitch is in the final needle thread loop 20b formed on the back surface of the sewing fabric at the end of normal sewing. , The final needle thread loop 20b is looped by itself to form a single-ring stitch. As a result, the looper thread 10 is held between the left needle thread 20 and the left final needle thread loop 20b as shown in FIG.

  In FIG. 18, the left final needle thread loop 20 b and the needle thread 20 are shown in a relaxed state to clearly show the entanglement, but the actual left final needle thread loop 20 b has passed the needle thread 20. Later, as shown in FIG. 19, it is strongly tightened to be in the same state as the right final needle thread loop 20a, and the looper thread 10 is firmly held between the needle thread 20 and the left final needle thread loop 20b. The left needle thread loop 20 and the left needle thread loop 20c formed one time before are restrained while being stretched. As shown in FIG. 19, since this constraint is maintained regardless of the force from which direction the looper thread 10 is applied, it is possible to reliably prevent fraying peculiar to the stitches M of the double chain stitch. it can.

  Japanese Patent Application No. 2011-016821   Japanese Patent Application No. 2011-115174

  As described above, the double chain stitch sewing machine with a stitch fray prevention device according to the patent application technology of the present applicant can effectively prevent the occurrence of fraying peculiar to the stitches of the double ring stitch. is there. However, in the double chain stitch sewing machine with a fraying prevention device according to the patent application technology of the present applicant, the following problems to be improved remain.

  That is, in the patent application technology by the present applicant, as shown in FIGS. 21 to 23, the thread hook 3, the stopper lever 4, the swing lever 9, which are components of the seam fray prevention device, The thread operation cylinder 32 and the stopper cylinder 42 were supported by a single needle plate base 11 which is long and large in the left-right direction and to which the needle plate P is attached and which is fixed to the upper surface of the sewing machine bed portion. More specifically, a support shaft 30 for swinging the thread hook lever 3 is supported at a position in the vicinity of the rear side of the needle plate P on the left side portion of the needle plate base 11, while the needle plate is provided on the right side portion of the needle plate base 11. The stopper lever 4, the swing lever 9, the thread operating cylinder 32 and the stopper cylinder 42 are supported at positions away from P, and forward from the tip of the swing lever 9 and the swing support shaft 30 of the thread hook 3. The structure that the connecting rod 35 was connected between the front-end | tip part of the extension part 3c extended so that it might return was taken. In FIG. 21 to FIG. 23, reference numeral 6 denotes a looper yarn holder that is fastened and fixed to the yarn hooking hook 3 via fixing screws 60, 60.

As described above, in the double chain stitch sewing machine according to the patent application technology already filed by the present applicant, all the components in the fraying prevention device of the seam are supported by the single needle plate base 11 which is long and large in the left-right direction. It had been. Therefore, after attaching the needle plate base 11 on which the constituent members of the anti-fraying device are assembled and supported to the upper surface of the sewing machine bed portion, for example, the sewing machine bed at the lower part of the needle plate base 11 such as a looper or a member for operating the looper Adjust the sewing tone by correcting the position and motion trajectory of the members that are contained in the sewing machine, or perform maintenance such as replacement of various parts that are also built into the sewing machine bed. When it is necessary to remove the needle plate P, it is not possible to secure a sufficiently large working space for adjustment and maintenance. Therefore, in order to secure a wide working space, the entire long and large needle plate base 11 is once removed from the sewing machine bed portion and subjected to predetermined adjustment and maintenance. The work which requires labor, such as attaching the whole 11 to a sewing machine bed part, is forced.

  In particular, air tubes 33 and 43 for supplying operating air to the cylinders 32 and 42 are connected to the thread operating cylinder 32 and the stopper cylinder 42. When the needle plate base 11 is removed and attached, these air tubes are connected. It is necessary to perform a very troublesome and time-consuming work such as dragging 33, 43 from the inside of the sewing machine bed so as not to obstruct the work, and pushing it into the sewing machine bed again after the work. In addition, if such troublesome and time-consuming adjustment and maintenance work is not performed, there is a possibility that the sewing tone may be deteriorated or the predetermined fraying prevention function may not be reproduced. As described above, there is no choice but to perform a very troublesome and labor-intensive work, and there remains a problem to be improved in this respect.

  The present invention has been made in view of the above circumstances, and can effectively prevent the occurrence of fraying peculiar to the stitches of double chain stitches, and also adjusts the sewing tone by correcting the position of members constituting the stitches. Also, maintenance such as replacement of various parts housed in the sewing machine bed can be performed very easily and easily without much trouble, labor and labor, and it has a sewing tone and a predetermined fraying prevention function. An object of the present invention is to provide a double chainstitch sewing machine with a fraying prevention device for a seam that can always be reliably reproduced.

In order to achieve the above object, a double chain stitch sewing machine with a stitch fray preventing device according to the present invention includes a needle that moves up and down while holding a needle thread, and a vertical movement path of the needle that holds a looper thread. A looper that can move forward and backward in a direction substantially perpendicular to the needle and that captures a needle thread loop formed by the needle below the needle plate during the advancement operation, and a needle attached to the needle plate and attached to the upper surface of the sewing machine bed portion And a needle base loop formed by the needle under the needle plate is captured by the looper, and the needle thread is looped with the looper thread held by the looper to double the sewing thread. A double chain stitch sewing machine for forming a seam of a chain stitch, which is capable of moving toward and away from the looper and spans between a standby position away from the looper and a threading position approaching the looper. The needle plate around the vertical support shaft A needle thread holding mechanism having a thread hook that swings in a parallel plane, and a hook actuator that swings and drives the thread hook to the standby position and the thread hook position, and a thread hook of the needle thread holding mechanism Is arranged at a position away from the needle plate so that the thread thread hook caught by the thread hooking position is held at a holding position between the thread hooking position and the standby position. A stopper member having a stopper member capable of temporarily stopping and releasing the swing of the hanging hook from the yarn hooking position to the standby position, a stopper mechanism for controlling the stopping and releasing of the stopper member, and the needle thread holding mechanism A connecting member for interlockingly connecting the thread hook and the stopper member of the stopper mechanism, and causing the looper to advance after finishing normal sewing, and the needle thread retainer The thread hook is moved closer to the looper to move the needle thread loop caught at the thread hooking position to the holding position, and this state is maintained to perform a sewing operation for at least one stitch. And a control unit for controlling the needle thread holding mechanism and the stopper mechanism in association with the vertical movement of the needle, the advance / retreat operation of the looper, and the feed operation of the sewing fabric, and a double ring with a fraying prevention device for stitches. In the sewing machine
The needle plate base includes a left needle plate base portion to which the needle plate is attached and which supports a swing support shaft of the thread hook, and a right needle plate that fixedly supports the stopper member, the hook actuator, and the stopper actuator. The right throat plate base is fixed to the sewing machine bed, and the left throat plate base is fastened and fixed to the upper surface of the sewing machine bed via a screw member. And it is attached so that fixation is possible.

  According to the double chain stitch sewing machine with a fraying prevention device of the seam according to the present invention having the above-described characteristic configuration, when the looper is advanced after finishing normal sewing, the thread of the needle thread holding mechanism By moving the hook close to the looper, moving the needle thread loop captured by the looper to the holding position, and maintaining this state to perform the sewing operation for at least one stitch, the needle that descends The needle thread loop held by the needle thread loops itself, and the looper thread is pressed at this loop looping part to prevent the looper thread from coming off. Can be prevented.

  In addition, in the present invention, the needle plate base attached to the sewing machine bed portion includes the left needle plate base portion to which the needle plate is attached and the thread hook of the needle thread holding mechanism is swingably supported, and the stopper mechanism. The right and left needle plate bases that fix and support the stopper member, hook actuator, and stopper actuator are divided into two parts, and the left and right side needle plate base parts are individually attached to the sewing machine bed part and frayed. Since the stopper device can be assembled to the sewing machine bed portion, the sewing bed portion of the entire fray stopper device is compared with the case where one long and large needle plate base is handled as in the patent application technology of the present applicant. Installation (assembly) with respect to can be easily performed with little effort.

  In addition, after assembling to the sewing machine bed, for example, the position and motion trajectory of the members constituting the sewing housed inside the sewing machine bed at the bottom of the needle plate base, such as the looper and its operating member, are corrected. When it is necessary to adjust the sewing tone, or when maintenance such as repair or replacement of various parts housed inside the sewing machine bed at the bottom of the needle plate base is required, air tubes or power It is not necessary to remove the right needle plate base part from the sewing machine bed part for fixing and supporting the hook actuator and stopper actuator to which the supply line is connected. It is possible to secure a sufficiently large working space just by removing it. Therefore, adjustment of the sewing tone and maintenance such as repair and replacement of various parts housed in the sewing machine bed are small and light, and only the left throat plate base where the air tube and power supply line are not attached It can be performed easily, easily and with good workability without much trouble, labor and labor by simply handling the handle, and this makes it possible to perform a good sewing tone and a predetermined fray prevention function with good reproducibility at all times. As a result, the present inventors have succeeded in solving the problems left in the already-applied patent application technology of the present applicant.

  In the double chain stitch sewing machine with a fraying prevention device according to the present invention, the stopper mechanism is engaged with a stopper member that is directly connected to the hook actuator and linearly reciprocates, and a part of the stopper member. A swing lever that can be disengaged, a spring that swings and biases the swing lever in a direction in which the thread hook is positioned at the standby position, and the swing lever that resists the biasing force of the spring. Preferably, the stopper actuator is disengaged from a part of the stopper member.

  In this case, the movement of the stopper member in the return direction (the movement in the direction in which the yarn hook is located at the standby position) is performed by the biasing force of the spring. The stopper actuator that operates the lever may be a stopper actuator that can push and drive the stopper member. Therefore, when an air cylinder is used as the stopper actuator, a single-action air cylinder can be used, and the stopper actuator can be reduced in size and cost.

  Further, in the double chain stitch sewing machine with a seam fray preventing device according to the present invention, the swing lever in the stopper mechanism is attached to a movable base attached to the right throat plate base portion so as to be adjustable in the left-right position. (Claim 3).

  In this case, the needle thread held by the thread hook is securely adjusted so that the self-looping to prevent fraying of the seam is performed by adjusting the position of the movable base to the right and left with respect to the right needle plate base. The timing at which the looper comes out of the loop can be adjusted easily and appropriately.

  Further, in the double chainstitch sewing machine with a stitch fray preventing device according to the present invention, the hook actuator of the needle thread holding mechanism and the stopper actuator of the stopper mechanism are arranged in two upper and lower stages on the lower surface of the right needle plate base. It is preferably fixedly supported in an overlapped state (claim 4).

  In this case, since the two actuators are fixedly supported on the right throat plate base in a state where the upper and lower layers are overlapped, the two actuators are arranged at positions separated from each other as in the patent application technology by the present applicant. Compared to the case where the actuators are juxtaposed, the plane space occupied by the actuator can be reduced and made compact, and can be housed in the machine bed portion in a good appearance.

  Further, in the double chain stitch sewing machine with a seam fray preventing device according to the present invention, the thread hook of the needle thread holding mechanism is provided between the thread hook position, the holding position and the standby position together with the thread hook. A looper thread holding body that holds the looper thread extending from the looper to the sewing fabric in front of the lowering position of the needle by swinging in a plane substantially parallel to the needle plate about the support shaft. It is preferable that it is attached (Claim 5).

  In this case, the looper thread is held at a position in front of the lowering position of the needle by the looper thread holder that operates together with the thread hook, so that the looper thread can be reliably positioned together with the needle thread with a simple configuration. be able to. Therefore, the self-looping can be reliably performed, and fraying of the seam can be more reliably prevented.

  Further, in the double chain stitch sewing machine with a fraying prevention device of the seam according to the present invention, it is preferable that the looper thread holding body is attached to the thread hook so as to be adjustable in position. .

  In this case, the relative position between the needle thread and the looper thread can be set appropriately, and the self-thread looping can be more reliably performed to further enhance the fraying prevention effect of the stitches.

  Moreover, in the double chain stitch sewing machine with a fraying preventing device for stitches according to the present invention, it is preferable that both the hook actuator of the needle thread holding mechanism and the stopper actuator of the stopper mechanism are air cylinders. .

In this case, it is possible to operate the thread hook in the needle thread holding mechanism and the swing lever in the stopper mechanism with good responsiveness based on the control signal from the control unit. The operation can be carried out reliably and efficiently.
As these actuators, electromagnetic solenoids may be used.

  Further, in the double chain stitch sewing machine with a stitch fray preventing device according to the present invention, a pin protrudes upward from the connecting end portion of the connecting member and the connecting end portion of the thread hook. It is preferable that a connection hole that can be inserted into the pin and extracted upward from above the pin is formed.

  In this case, in order to perform adjustments such as adjusting the sewing tone and repairing or replacing various parts housed in the sewing machine bed, the left needle plate base is fixed to the sewing machine bed from the upper surface, and the sewing machine bed When removing the upper part of the head, the left needle plate base part can be removed without the need for troublesome operations such as loosening and removing the connecting screw between the connecting member and the thread hook and pulling out the connecting pin. It is possible to release the connection between the thread hook and the connecting member simply by lifting up. Further, after the adjustment and maintenance described above, the thread hook and the connecting member can be returned to the connected state simply by fixing the left needle plate base to the sewing machine bed from above. As a result, the above-described adjustment and maintenance work can be further simplified.

  Furthermore, in the double chain stitch sewing machine with a fraying prevention device of the seam according to the present invention, the left needle plate base or the machine bed is provided at a plurality of locations separated from a plurality of fixed connection and connection release locations by the screw member. Further, a knock pin capable of positioning the left needle plate base portion with respect to the sewing bed portion is projected, and a pin hole that can be fitted to the knock pin is formed in the sewing bed portion or the left needle plate base portion. (Claim 9).

  In this case, when the left needle plate base is attached to or detached from the sewing machine bed, the left needle plate base is securely positioned at a predetermined position of the sewing machine bed by fitting a plurality of dowel pins and pin holes. be able to. Therefore, even if the left throat plate base is repeatedly attached to and detached from the sewing machine bed during the above adjustment and maintenance, the left throat plate base is always attached to the sewing machine bed while maintaining a predetermined position and posture. be able to. As a result, not only the normal sewing but also the fraying prevention function of the seam can always be properly and reliably performed.

  In addition, the fraying prevention device of the seam according to the present invention can be suitably applied to a horizontal cylindrical double chain stitch sewing machine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall perspective view of a horizontal cylindrical double chain stitch sewing machine with a seam fray preventing device according to an embodiment of the present invention. It is a perspective view which shows the structure of the principal part of the fraying prevention apparatus of the seam in a horizontal cylindrical double chain stitch sewing machine same as the above. It is a perspective view which shows the state which removed a part of structure of the principal part of the fraying prevention apparatus same as the above. It is a top view which shows the structure of the principal part of the fraying prevention apparatus of a seam same as the above. It is a bottom view of the principal part explaining the structure and 1st operation | movement of a stopper mechanism of the fraying prevention apparatus of a seam same as the above. It is a bottom view of the principal part explaining a structure and 2nd operation | movement of a stopper mechanism same as the above. It is a bottom view of the principal part explaining a structure and 3rd operation | movement of a stopper mechanism same as the above. It is a bottom view of the principal part explaining a structure and 4th operation | movement of a stopper mechanism same as the above. It is a block diagram which shows the structure of the control system of a horizontal cylinder type double chain stitch sewing machine including the fray prevention device of a seam same as the above. It is a time chart explaining the operation | movement content of the control part in the fraying prevention apparatus of a seam same as the above. It is explanatory drawing of the 1st fraying prevention operation | movement by the fraying prevention apparatus of a seam same as the above. It is explanatory drawing of the 2nd fraying prevention operation | movement by the fraying prevention apparatus of a seam same as the above. It is explanatory drawing of the 3rd fraying prevention operation | movement by the fraying prevention apparatus of a seam same as the above. It is explanatory drawing of the 4th fraying prevention operation | movement by the fraying prevention apparatus of a seam same as the above. It is explanatory drawing of the 5th fraying prevention operation | movement by the fraying prevention apparatus of a seam same as the above. It is explanatory drawing of the 6th fraying prevention operation | movement by the fraying prevention apparatus of a seam same as the above. It is explanatory drawing of the 7th fraying prevention operation | movement by the fraying prevention apparatus of a seam same as the above. It is the figure which looked at the stitch structure of the 2 needle double chain stitch obtained by the present invention from the back of the sewing cloth. It is explanatory drawing of the fraying prevention effect of the stitch structure shown in FIG. It is the figure which looked at the common stitch structure of the sewing end part from the back surface of the sewing fabric. It is a top view which shows schematically the structure of the principal part of the fraying prevention apparatus of the stitch in the patent application technique by this applicant. It is a bottom view which shows schematically the structure of the principal part of the fraying prevention apparatus of the stitch in the patent application technique by the present applicant same as the above. It is a top view explaining the operation | movement state of the principal part of the fraying prevention apparatus of the stitch in the patent application technique by this applicant same as the above.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an overall perspective view of a horizontal cylindrical double chain stitch sewing machine according to an embodiment of the present invention. FIGS. 2 and 3 are stitches provided in the horizontal cylindrical double chain stitch sewing machine according to the present invention. FIG. 4 is a plan view showing the configuration of the main part of the fraying prevention device of the seam. In the following description, the expressions “left, right” and “front, rear” indicated by arrows in FIGS. Here, “front” is the side closer to the sewing manufacturer, “rear” is the side away from the sewing manufacturer, and “left, right” is “left, right” when viewed from the front closer to the sewing manufacturer. It is.
Moreover, in this Embodiment, it demonstrates using the same code | symbol for the structural member and structural part which are the same as or correspond to the patent application technique by the present applicant demonstrated based on FIGS. 21-23.

  As shown in FIG. 1, the horizontal cylindrical double chain stitch sewing machine according to the embodiment of the present invention includes a sewing machine arm portion C and a sewing bed portion B that are substantially parallel to each other from the vertical position of the sewing machine body D to the left. It extends in parallel. As shown in FIG. 4, the horizontal cylindrical double chain stitch sewing machine includes a looper 1, two needles 2 and 2 (see FIGS. 11 to 17), and a needle attached to the upper surface of the sewing machine bed portion B. A plate base 11, a fray preventing device H for stitches provided on the needle plate base 11, and a needle plate P attached on the needle plate base 11 are provided. The needles 2 and 2 are raised and lowered through the operation of the needle bar drive mechanism. A and A in FIGS. 2 and 4 indicate the needle drop positions (lower positions) of the needles 2 and 2. The needle drop positions A and A are set at an approximate center of the needle plate P with a gap in the left-right direction.

  The looper 1 moves forward and backward (leftward and rightward) in the direction in which the needles 2 and 2 (needle drop positions A and A) are arranged through the operation of the looper driving mechanism. The solid line in FIG. 4 shows a state where the looper 1 is moved to the leftward position, and the broken line in FIG. 4 shows a state where the looper 1 is moved to the rightward position. As shown by the solid line in FIG. 4, the tip of the looper 1 in the leftward position extends leftward beyond the needle drop positions A and A, and is in the rightward position as shown by the broken line in FIG. The tip of the looper 1 is located to the right of the needle drop positions A and A.

The horizontal cylindrical double chain stitch sewing machine sews the sewing fabric (not shown) set on the needle plate P by the upward and downward movements of the needles 2 and 2 and the leftward and rightward movements of the looper 1. . The sewing fabric is pressed onto the needle plate P by a presser foot (not shown), and is fed and moved in the direction of arrow Y in FIG. 4 by the operation of the feed mechanism provided inside the sewing machine bed B. The feed mechanism is provided with a feed dog that protrudes above the needle plate P and moves backward, and that repeats an operation of being immersed under the needle plate P and returning to the front direction. The feed is intermittently moved in the arrow Y direction.

  The needle bar drive mechanism, looper drive mechanism, and feed mechanism described above are known mechanisms that operate in synchronization with each other by transmission from a sewing machine main shaft (not shown). The needles 2 and 2 hold the needle threads 20 and 20 (see FIGS. 11 to 17) separately, and pass through the sewing fabric and below the needle plate P while the sewing fabric stops moving. Then, it rises and exits above the sewing fabric. The looper 1 holds the looper thread 10 (see FIGS. 11 to 17), moves to the left as the needles 2 and 2 start to rise, and loops 20a and 20a of the needle threads 20 and 20 formed below the needle plate P. Capture 20b. The sewing fabric is fed and moved when the needles 2 and 2 are raised. The needles 2 and 2 descend through the sewing fabric that has been fed and catch the looper thread 10 held by the looper 1 that is retracting to the right. The double chain stitch sewing machine repeats the above operation to form double chain stitch stitches on the sewing fabric.

The fraying prevention device H provided in the horizontal cylindrical double chain stitch sewing machine as described above includes a needle thread holding mechanism, a stopper mechanism, a thread hook 3 (described later) of the needle thread holding mechanism, and the stopper mechanism. A connecting rod 35 as a connecting member for interlockingly connecting the stopper member 4 (described later) and a control unit 8 (described later).

  The needle thread holding mechanism has a vertical hook 30 that extends between a thread hook 3 and a standby position where the thread hook 3 is separated from the looper 1 and a thread hook position close to the looper 1. And a reciprocating thread manipulating cylinder 32 as a hook actuator for driving and swinging as a center. A support shaft 30 serving as a swing center of the thread hook 3 is disposed in the vicinity of the right rear corner of the needle plate P and is supported on the needle plate base 11.

  The thread hook 3 has an arcuate curved shape, and is continuously connected to the front end portion of the support arm 3e extending leftward from the support shaft 30 so as to be folded forward. The front end portion of the thread hook 3 faces the needle drop positions A and A from the rear left side on the lower side of the needle plate P, and a hook portion 3b protruding outward is formed at the front end portion. Yes. The support arm 3e has an extending portion 3c that extends forward from the support shaft 30, and one end of a connecting rod 35 is connected to the tip of the extending portion 3c.

  As shown in FIG. 4, a looper yarn holder 6 having an arcuate curved shape is fastened to the base of the yarn hook 3 with two fixing screws 60, 60. The tip of the looper thread holder 6 extends forward substantially along the left side of the yarn hook 3 and faces the needle drop positions A and A at a position in front of the tip of the yarn hook 3. Is formed with a looper yarn receiving portion 6a that is bifurcated. The position of the looper holder 6 can be adjusted with respect to the thread hook 3 by loosening the fixing screws 60, 60, and this position adjustment ensures that the looper thread 10 is held by the looper thread receiving portion 6a at the tip. It is configured.

  As shown in FIGS. 5 to 8, the stopper mechanism is fixed to the distal end portion (left end portion) of the output rod 31 of the yarn operation cylinder 32 via a set screw 36 and supplied via an air tube 33. A stopper member 4 that linearly reciprocates in the left-right direction when the yarn operation cylinder 32 is expanded and contracted by the operating air, and a swing lever 9 that can be engaged with and released from a part of the stopper member 4. A spring 91 that engages the swing lever 9 with a part of the stopper member 4 and biases the thread hook 3 in the direction in which the yarn hook 3 is positioned at the standby position; On the other hand, the swing lever 9 is constituted by a one-acting (extrusion drive type) stopper cylinder 42 as a stopper actuator for forcibly releasing the engagement from a part of the stopper member 4. To have.

  The output rod 41 of the stopper cylinder 42 causes the swing lever 9 to swing and bias the spring 91 as the stopper cylinder 42 is pushed out to the left by the operating air supplied through the air tube 43. It is configured to swing counterclockwise against this.

  The swing lever 9 is supported on the upper surface of a swing lever mounting base (movable base) 92 so as to be swingable about a vertical support shaft 90. The swing lever 9 has an engaging claw 9a that can be engaged with a part of the stopper member 4 at the tip, and as shown in FIG. Is moved to the left, that is, when the yarn hook 3 is moved to the standby position, the biasing force of the spring 91 makes contact with the side of the stopper member 4 and the yarn operating cylinder 32 contracts. When the stopper member 4 is driven and moved to the right by the operation, as shown in FIG. 6, the engaging claw 9a at the tip is swung clockwise around the support shaft 90 by the biasing force of the spring 91. The stopper member 4 can be engaged with a part.

  Further, as shown in FIG. 7, when the contracted yarn operating cylinder 32 is again extended by a small amount, the engaging claw 9a at the tip of the swing lever 9 is engaged with a part of the stopper member 4, and the stopper The drive movement of the member 4 in the left direction is temporarily stopped. In this state where the stopper member 4 is temporarily stopped, the thread hook 3 is moved to a holding position between the standby position and the thread hook position via the connecting rod 35 and stopped. At this time, the hook portion 3b at the tip of the thread hook 3 moves from the thread hook position shown in FIG. 4 (between the left and right needle drop positions A and A) to the left rear of the needle drop position A on the left side. The left needle thread 20 is hooked and held in the holding position. Further, the looper yarn holder 6 advances to the front side of the looper 1 and the looper yarn receiving portion 6a at the tip holds the looper yarn 10 in front of the needle drop position A on the left side.

  Further, as shown in FIG. 8, the output rod 41 is pushed out to the left as the stopper cylinder 42 is extended, so that the swing lever 9 is counterclockwise against the swing biasing force of the spring 91. The engaging claw 9a at the tip of the swing lever 9 is disengaged from a part of the stopper member 4, and the temporary stop of the stopper member 4 is released. As a result, the yarn operating cylinder 32 is extended to the maximum, and the yarn hook 3 and the looper yarn holder 6 are returned to the standby position via the connecting rod 35.

  As described above, in the present embodiment, the thread hook 3 and the looper thread holder 6 of the needle thread holding mechanism are moved to the above-described standby position, thread hooking position, Swing between the holding position.

Further, the horizontal cylindrical double chain stitch sewing machine in the present embodiment includes a thread trimming mechanism 5 that cuts the needle thread 20 and the looper thread 10 after the end of sewing. As shown in FIGS. 16 and 17, the thread trimming mechanism 5 includes a thread trimming hook 50, a thread trimming knife 51, a leaf spring 59 that presses the thread trimming hook 50 against a sliding contact portion with the thread trimming knife 51, and A thread trimming actuator 58 (see FIG. 9). The thread trimming hook 50 is provided with a first hook portion 52 and a second hook portion 53 projecting rearward at the tip portion. Since the thread trimming mechanism 5 is publicly known, description and illustration of other detailed configurations are omitted.

FIG. 9 is a block diagram showing the configuration of the control system of the horizontal cylindrical double chain stitch sewing machine including the seam fray preventing device H as described above.
The control unit 8 of the double chain stitch sewing machine includes a depression signal 21a and a return signal 21b by the pedal switch 21, a needle position signal 22 transmitted when the needles 2 and 2 are in the vicinity of the top dead center, and a thread trimming. A signal 23 and a needle thread wiping signal 24 are input.

  On the other hand, the control unit 8 outputs an operation control signal to each of the yarn operation cylinder 32, the stopper cylinder 42, and the yarn trimming actuator 58. The yarn hook 3 and the looper yarn holder 6 operate as described above according to the operation control signals output from the control unit 8 to the yarn operation cylinder 32 and the stopper cylinder 42, and the yarn trimming actuator 58 of the yarn trimming mechanism (not shown). Are expanded and contracted according to the thread trimming signal 23 output from the control unit 8.

  Further, the control unit 8 includes a sewing machine motor 80 that is a driving source of the sewing machine main shaft, a presser foot cylinder 81 that raises and lowers the presser foot for presser foot, an air wiper 82 that flips up the needle threads 20 and 20 that are cut as will be described later. Operation control signals are also output to the feed reduction mechanism 83 that adjusts the feed amount of the sewing fabric and the looper thread suppression mechanism 84 that suppresses the feed of the looper thread 10 to the looper 1.

  The feed reduction mechanism 83 changes the operation mode of the feed dog in the feed mechanism, for example, by tilting the operation path of the feed dog with respect to the needle plate P to shorten the protrusion time on the needle plate P, thereby Shorten the time for the feed dog to act on the sewing fabric on P or change the length of the lever that circulates the feed dog to reduce the unit feed pitch by the feed dog, etc. Since the feed reduction mechanism 83 is known in the art, detailed illustration and description thereof will be omitted.

  The looper yarn suppressing mechanism 84 includes a yarn tension plate that clamps a midway portion of the looper yarn 10 that is fed into the looper 1, and an actuator that operates to increase or decrease the looper yarn clamping strength of the yarn tension plate. The looper yarn clamping strength by the tension plate is increased to increase the resistance applied to the looper yarn 10, thereby suppressing the feeding of the looper yarn 10. Since such a looper yarn suppressing mechanism 84 is known, Detailed illustration and description are omitted.

  After the end of forming the double chain stitch, the control unit 8 moves the thread hook 3 and the looper thread holder 6 to the sewing machine motor 80, the presser foot cylinder 81, the air wiper 82, the feed reduction mechanism 83, and the looper thread. By operating in conjunction with the suppression mechanism 84, the fraying prevention operation of the stitches of the double chain stitch is executed.

  FIG. 10 is a time chart showing the operation contents of the control unit 8 for preventing fraying in time series. The control unit 8 is a computer including a CPU, a ROM, and a RAM. The fraying prevention operation according to the time chart of FIG. 10 is executed by a series of operations of the CPU according to a control program stored in the ROM.

FIGS. 11 to 17 are explanatory views of the fraying prevention operation by the fraying prevention device H in the horizontal cylindrical double chain stitch sewing machine of the present invention, and the thread hook 3 generated by the operation of the control unit 8 according to the time chart of FIG. The operation state of the looper thread holder 6 and the thread trimming hook is shown.

  When a sewing manufacturer using a sewing machine finishes normal sewing, he / she stops stepping on the pedal for driving the sewing machine and then performs fraying prevention operation. In this case, depress the pedal. Manipulate. The pedal switch 21 is attached to the pedal, and outputs a depression signal 21a during a depression operation, and outputs a depression signal 21b when a depression operation is performed.

  When the normal sewing is completed and the pedal for driving the sewing machine is returned from the depressed state to the neutral state, that is, the control unit 8 performs the depression signal 21a and the depression from the pedal switch 21. When none of the signals 21b is output, a stop command is output to the sewing machine motor 80 with reference to the needle position signal 22 given to the input side. As a result, the sewing machine pauses with the needles 2 and 2 in the vicinity of the top dead center and the looper 1 moving to the left.

  Thereafter, the control unit 8 stands by until the pedal is turned back. When the stepping operation is performed at the time of S2 in FIG. 10 and the stepping signal 21b is input to the input side, the control unit 8 starts the fraying stop operation described below. The control unit 8 returns to the normal sewing operation when the depression signal 21a is input again from the pedal switch 21, so that the sewing manufacturer continues the normal sewing by depressing the pedal again. be able to.

  In FIG. 10, the neutral state is to be maintained from the time point S1 to the time point S2, but this neutral state is not necessarily maintained, and the pedal at the end of normal sewing is not necessarily required. This operation may be continuously shifted from the depressed state to the depressed state. In this case, when passing through the neutral position during the transition process, neither the depression signal 21a nor the return signal 21b is output, and the control unit 8 uses the no-signal state as a trigger as described above. After the needles 2 and 2 are raised near the top dead center and the looper 1 is moved leftward, the fraying prevention operation is started.

  Further, in the time chart of FIG. 10, the pedal return operation at the time of S2 is to be continued during the execution of the fraying prevention operation described below. It is not necessary to continue until the operation is completed, and the fraying prevention operation is continuously performed by the operation of the control unit 8 even after the input of the stepping signal 21b is stopped.

  FIG. 11 shows a state of the needles 2 and 2 and the looper 1 at the start of the fraying prevention operation. The needles 2 and 2 are in a state where they are pulled out above the sewing cloth in which the stitches M of the double ring stitch are formed by the two needle threads 20 and 20 and the one looper thread 10. The looper 1 moves to the left under the sewing fabric and is in a state where the two needle thread loops 20a and 20b formed by the needles 2 and 2 are captured. When the needle threads 20 and 20 and the looper thread 10 are cut in this state, a sewing end portion as shown in FIG. 20 is formed.

  After the fraying stop operation is started, the control unit 8 first gives an operation command to the output side thread operation cylinder 32. As a result, the thread operating cylinder 32 operates from the extended state shown in FIG. 5 to the contracted state shown in FIG. 6, and the stopper member 4 is driven to move rightward. Accordingly, the thread hook 3 and the looper thread holder 6 are moved. Swings around the support shaft 30 via the stopper member 4 and the connecting rod 35 and moves from the standby position to the thread hooking position. At this time, the hook portion 3b at the tip of the thread hook 3 is on one side (left side). While hooking the needle thread loop 20 a, the swing lever 9 in the stopper mechanism swings clockwise around the support shaft 90 by the biasing force of the spring 91, and the engaging claw 9 a at the tip thereof is a part of the stopper member 4. Can be engaged.

  Immediately thereafter, the control unit 8 gives an operation command to the yarn operation cylinder 32, and the yarn operation cylinder 32 is slightly extended from the state shown in FIG. 6 to the state shown in FIG. Driven to the left. When the thread operating cylinder 32 is extended by a small amount, the engaging claw 9 a at the tip of the swing lever 9 is engaged with a part of the stopper member 4. As a result, the leftward drive movement of the stopper member 4 is temporarily stopped. In the state where the leftward movement of the stopper member 4 is temporarily stopped in this way, as shown in FIG. 12, the thread hook 3 is connected to the standby position and the thread hook position via the connecting rod 35. And the left needle thread loop 20a is held in the holding position, and the looper thread holding body 6 advances to the front side of the looper 1 and the looper thread receiving portion 6a at the tip. Holds the looper thread 10 in front of the needle drop position A on the left side.

  After stopping the yarn hook 3 and the looper yarn holder 6 from moving at the holding position as described above, the control unit 8 controls the sewing machine motor 80, the feed reduction mechanism 83, and the looper yarn suppression mechanism at the time of S3 in FIG. An operation command is given to 84. This operation command is given with reference to the needle position signal 22 until the needles 2 and 2 are raised again to the position near the top dead center after the needles 2 and 2 are lowered. As a result, a sewing operation for one stitch is performed on the sewing fabric. The sewing for one stitch is executed under a feed amount smaller than that during normal sewing by the operation of the feed reduction mechanism 83. Further, the sewing for one stitch is executed in a state where the feeding of the looper thread 10 to the looper 1 is suppressed by the operation of the looper thread suppression mechanism 84. As a result, tightening of the looper thread 10 at the end of sewing is improved, and the fraying prevention effect described later can be enhanced.

  As shown in FIG. 12, the thread hook 3 and the looper thread holder 6 hold the needle thread 20 and the looper thread 10 by completing the feed movement of the sewing fabric, and the needles 2 and 2 penetrate the sewing fabric. The needle 2 is lowered and continues until the left needle 2 passes through the needle thread loop 20a held by the thread hook 3 and catches the needle thread loop 20a. At this time, the looper thread 10 held by the looper thread holder 6 is positioned so as to cross the front side of the left needle 2 as shown in FIG. Accordingly, the left needle 2 does not catch the looper yarn 10, and the looper yarn 10 is only caught on the rear side of the looper 2 by the right needle 2.

  The control unit 8 gives an operation command to the stopper cylinder 42 of the stopper mechanism at the timing when the left needle 2 catches the needle thread loop 20a, that is, at the time of S4 in FIG. Along with this, the output rod 41 is driven to push leftward. As a result, as shown in FIG. 8, the swing lever 9 is swung counterclockwise against the swing biasing force of the spring 91, and the engaging claw 9 a at the tip of the swing lever 9 is moved. The engagement is released from a part of the stopper member 4, and the temporary stop of the stopper member 4 is released. By releasing the stop with respect to the stopper member 4 as described above, the yarn operation cylinder 32 is extended to the maximum at the time of S4. As a result, as shown in FIG. 13, the yarn hook 3 and the looper yarn holder 6 swing around the support shaft 30 via the stopper member 4 and the connecting rod 35 and return from the holding position to the standby position. Then, the holding of the needle thread loop 20a and the looper thread 10 is released.

  Then, the looper 1 moves to the right as the needles 2 and 2 descend, and comes out of the captured needle thread loop 20a. As shown in FIG. 14, when the looper 1 is pulled out, the right needle 2 is in a state of capturing the looper thread 10 in the same manner as in normal sewing, while the left needle 2 is in the left needle thread loop 20a. It will be in the state where was captured.

  In this state, the looper 1 turns to the left and the hands 2 and 2 turn up. As shown in FIG. 15, the leftward looper 1 catches the left and right needle thread loops 20a and 20b, and the ascending needles 2 and 2 come out above the sewing fabric. As a result, the needle thread 20 captured by the looper 1 loops the looper thread 10 at the position of the right needle 2 while looping the looper thread 10 at the position of the left needle 2, while the needle thread loop 20 a formed earlier is needled. Looping with the yarn 20, so-called self-looping.

  After the sewing operation for one stitch, the needles 2 and 2 are raised to the vicinity of the top dead center, and the looper 1 is finished in the state of reaching the vicinity of the leftward end. After that, the control unit 8 waits until the thread trimming signal 23 is given. When the thread trimming signal 23 is given at the time of S5 in FIG. By causing the cutting actuator 58 to perform a predetermined operation, the thread cutting hook 50 reaches the advancing end along the upper portion of the looper 1 as shown in FIG. At this time, the first hook portion 52 at the distal end portion of the thread trimming hook 50 reaches the left side of the looper yarn 10 extending from the distal end of the looper 1 to the sewing fabric through the needle thread loops 20a and 20b held by the looper 1. The second hook portion 53 faces the left needle thread 20 from the left side.

  Subsequently, the thread trimming hook 50 that has reached the advanced end moves backward. At this time, the first hook portion 52 captures the looper thread 10 and the second hook portion 53 sequentially captures the two needle threads 20 and 20. The looper thread 10 and the needle threads 20, 20 thus captured are pulled to the retracted end of the thread trimming hook 50, and are brought into sliding contact with the leading edge portion of the thread trimming knife 51 as shown in FIG. It will be cut off. The end portion of the cut looper yarn 10 is held in a state of being sandwiched between the yarn cutting hook 50 and the leaf spring 59 on the looper 1 side from the cutting position.

  The looper yarn suppressing mechanism 84 continues to operate until the above-described thread trimming operation is completed, and applies a predetermined tension to the looper yarn 10 extending from the tip of the looper 1 to the sewing fabric. As a result, the first hook portion 52 at the tip of the thread trimming hook 50 can reliably capture and cut the looper thread 10 without looseness.

  After completing the cutting operation as described above, the control unit 8 stands by until the needle thread wiper signal 24 is input. When the needle thread wiper signal 24 is input at S6 in FIG. An operation command is output to operate the air wiper 82. The air wiper 82 blows out air and jumps up the cut ends of the needle threads 20 and 20 that are continuous with the needles 2 and 2. Thereafter, the control unit 8 outputs an operation command to the presser foot cylinder 81 at the time of S7 in FIG. 10 to operate the presser foot cylinder 81, and raises the presser foot for presser foot to perform a series of fraying prevention operations. finish.

By the series of fraying prevention operations described above, the structure of the double chain stitch seam M by the horizontal cylindrical double chain stitch sewing machine as shown in FIG. 18 is obtained. As shown in FIG. 18, the looper thread 10 is formed on the right side (the left side in FIG. 18 when the seam M is viewed from the back side of the sewing fabric) formed on the back side of the sewing fabric at the end of the double chain stitch seam M. ) In the needle thread loop 20a, and then folded back in front of the needle thread 20 on the same side that slips out to the back of the sewing fabric during the sewing operation for preventing fraying. It is cut at the position that passed again.

  On the other hand, the needle thread 20 on the left side (the right side in FIG. 18) that slips out to the back of the sewing fabric during the sewing operation for one stitch for preventing fraying is the sewing fabric at the end of normal sewing as described above. The left final needle thread loop 20b is looped by passing through the left needle thread loop 20b formed on the back surface thereof to form a single ring stitch. Therefore, as shown in FIG. 18, the looper thread 10 is held between the left needle thread 20 and the left final needle thread loop 20b.

  In FIG. 18, the left final needle thread loop 20b is shown in a relaxed state to clearly show the entanglement with the needle thread 20, but the actual left final needle thread loop 20b passes through the needle thread 20. After that, as shown in FIG. 19, it is tightly tightened to be in the same state as the right final needle thread loop 20a. Then, as shown in FIG. 19, when the cut end of the looper thread 10 is pulled in the direction of the arrow, the loop of the looper thread 10 passing in front of the right needle thread 20 is reduced, and the right final needle thread loop 20a. Drawn into. As a result, the needle thread 20 is sandwiched between the looper thread 10 and the right final needle thread loop 20a, and the needle thread 20 and the looper thread 10 form a “knot” as shown in FIG. Is formed. Since this “knot” also functions to add resistance to the looper thread 10 and prevent the looper thread 10 from coming off, when the state shown in FIG. The fraying can be surely prevented by the synergistic action of the left-hand thread looping portion and the right “knot”.

  The configuration described in detail above, and the characteristic configuration of the double chainstitch sewing machine with a fraying prevention device of the seam that performs the fraying prevention operation as described above, that is, the patent application technology by the present applicant. The improved configuration adopted by the present invention in order to solve the problems remaining in the above will be described below with reference to FIGS.

  As shown in FIGS. 2 to 4, the needle plate base 11 attached to the upper surface of the sewing machine bed portion B is divided into a left needle plate base portion 11 </ b> L and a right needle plate base portion 11 </ b> R. The left throat plate base 11L has the throat plate P removably attached to the upper surface thereof via a set screw 100, and a support shaft 30 serving as a swing center of the thread hook 3 of the needle thread holding mechanism. I support it.

  The needle plate near the front end (left end) near the left end of the left needle plate base 11L divided into two parts, specifically, near the front end (left end) of the sewing machine arm portion C indicated by the phantom line in FIG. Screw holes 101 are formed at locations apart from the P mounting locations, and the left throat plate base portion 11L is fastened to the upper surface of the sewing machine bed portion B through set screw members 102 that are screwed into the screw holes 101. It is attached so that it can be fixed and released (removable).

  Further, as shown in FIG. 3, the upper surface of the sewing machine bed portion B and the left throat plate base portion 11L are provided with knock pins 103 and the knock pins 103 at locations apart from the two fastening fixing locations by the set screw member 102. A pin hole 104 to be fitted is formed, and the left needle plate base portion 11L is positioned at a predetermined position and posture with respect to the sewing machine bed portion B by inserting and fitting the pin hole 104 into the knock pin 103 from above. In this state, the left needle plate base 11L can be fastened and fixed to the upper surface of the sewing machine bed B by screwing the set screw member 102 into the screw hole 101.

  In the present embodiment, the knock pin 103 is protruded upward from the upper surface of the sewing machine bed portion B, and the pin hole 104 is formed in the left throat plate base portion 11L. 103 may protrude downward from the lower surface of the left needle plate base 11L, and the pin hole 104 may be formed on the upper surface of the sewing machine bed portion B.

  On the other hand, the right needle plate base portion 11R divided into two forms a cylinder mounting base portion that supports the thread operating cylinder 32 and the stopper cylinder 42 (hereinafter, the right needle plate base portion 11R is referred to as a cylinder mounting base portion). The above-described stopper mechanism is disposed below the cylinder mount 11R. Specifically, as shown in FIGS. 5 to 8, the thread operating cylinder 32 is fixedly supported on the lower surface of the cylinder mounting base portion 11 </ b> R via the mounting screw 105, and at the lower part of the thread operating cylinder 32. The stopper cylinders 42 are arranged in a two-tiered manner, and the stopper cylinders 42 are fixedly supported on the cylinder mounting base portion 11R via mounting screws 106.

  The cylinder mounting base portion 11R is assembled to the side surface of the sewing machine bed portion B through a set screw member 107 in a fixed state. Here, the fixed state means that the anti-fraying device H is fixed to a predetermined position by tightening the set screw member 107 when the anti-fraying device H is assembled to the sewing machine bed portion B. Refers to the state fixed in position.

  One end (right end) of the connecting rod 35 is rotatably connected to the stopper member 4 in the stopper mechanism by a pin screw 108. A stopper member that linearly reciprocates in the left-right direction as the thread operating cylinder 32 expands and contracts is provided on the cylinder mounting base portion 11R at a location corresponding to the connecting portion of the one end of the connecting rod 35 and the stopper member 4 by the pin screw 108. A long long groove 109 is formed along the left-right direction so as to allow 4 linear reciprocating movements.

  Further, a connecting end portion 35a connected to the extending portion 3c connected to the yarn hook 3 at the other end of the connecting rod 35 is bent downward by substantially the thickness of the extending portion 3c. A pin 110 protrudes upward from the connecting end portion 35a of the connecting rod 35 bent downward, and can be inserted into the extended portion 3c from above the pin 110. Further, a connecting hole 111 that can be extracted upward is formed. As a result, when the left needle plate base 11L is released from the sewing machine bed B after being unfixed from the sewing machine bed B, the connecting rod 35 and the extending part 3c are fixedly connected, for example, a set screw or the like is loosened. Then, it is not necessary to perform the operation of releasing the interlocking state of both, and by simply lifting the left throat plate base 11L upward, the connection hole 111 of the extending portion 3c is extracted upward from the pin 110 and connected to the connection rod 35. It is possible to release the interlocking state with the extending portion 3c (thread hook 3). Further, when attaching the left needle plate base 11L to the sewing machine bed portion B, the connecting hole 111 is inserted into the pin 110 from above only by moving the left needle plate base 11L from above toward the sewing bed portion B. It is possible to return the connecting rod 35 and the extending portion 3c (thread hook 3) to the interlocking state. The connecting end portion 35a of the connecting rod 35 does not necessarily have to be bent downward. That is, the connecting rod 35 may have a flat plate shape over its entire length.

  Further, a swing lever mounting base (movable base) 92 that supports the swing lever 9 in the stopper mechanism so as to be swingable about a support shaft 90 in the vertical direction is provided on the cylinder mounting base portion 11R with a long length in the left-right direction. It is attached to the left and right via a hole 93 and a set screw 94 so that the position can be adjusted. This is because the swing lever mounting base 92 is adjusted to the left and right with respect to the cylinder mounting base portion 11R even after the cylinder mounting base portion 11R is fixed to the sewing machine bed portion B via the set screw member 107. As a result, it is possible to arbitrarily adjust the timing at which the looper 1 comes out of the needle thread loop 20a held by the thread hook 3 and thereby reliably performs looping of the own thread to prevent fraying of the seams. It is made to be able to be made.

In the horizontal cylindrical double chain stitch sewing machine of the present embodiment having the seam fraying prevention device H adopting the characteristic configuration as described above, the seam fraying prevention device H is assembled to the sewing machine bed portion B. At this time, the left needle plate base 11L and the right cylinder mounting base 11R of the needle plate base 11 divided into right and left can be individually attached to the sewing machine bed B. Therefore, compared with the case where a single long and large needle plate base is handled as in the already applied patent application by the present applicant, the attachment (assembly) work to the sewing machine bed portion B of the fray prevention device H as a whole can be performed with less effort. It can be carried out.

  In addition, after the needle plate base 11 (the left needle plate base portion 11L and the right cylinder mounting base portion 11R) is once assembled to the sewing machine bed portion B, for example, the needle plate base 11 such as the looper 1 or its operating member. If it is necessary to adjust the sewing tone by correcting the position and movement locus of the members constituting the sewing housed inside the sewing machine bed B at the lower part of the sewing machine, or the sewing machine at the lower part of the needle plate base 11 When maintenance such as repair or replacement of various parts housed in the bed part B becomes necessary, the thread operating cylinder 32 and the stopper cylinder 43 to which the air tubes 33 and 43 are connected are set at predetermined positions. It is not necessary to remove the cylinder mounting base 11R that is firmly fixed to the sewing machine bed B, and only the left needle plate base 11L is unfixed from the sewing bed B and removed. It is possible to ensure a sufficiently large working space.

  Therefore, by adjusting only the left throat plate base 11L, which is small and light, and the air tubes 33 and 43 are not attached to each other, adjustment of the sewing tone, repair of various parts housed in the sewing machine bed B, Maintenance such as replacement can be performed very easily, simply and with good workability. As a result, it is possible to always exhibit a good sewing tone and a predetermined fraying prevention function with good reproducibility, and to solve the problems remaining in the already-patented application technology by the present applicant.

  Further, as in the present embodiment, a configuration is adopted in which the swing lever 9 in the stopper mechanism is swing-biased using the spring 91 in the direction in which the thread hook 3 in the needle thread holding mechanism is located at the standby position. As a result, the movement of the stopper member 4 in the return direction (the movement in the direction in which the yarn hook is located at the standby position) is performed by the biasing force of the spring 9, so that the stopper member 4 is engaged and disengaged partially. Since a single-acting air cylinder can be used as the stopper cylinder 42 for operating the swing lever 9 that moves, the stopper cylinder 42 can be reduced in size and cost.

  Further, as in the present embodiment, a configuration in which the thread operating cylinder 32 in the needle thread holding mechanism and the stopper cylinder 42 in the stopper mechanism are fixedly supported on the lower surface of the cylinder mounting base portion 11R in a two-tiered state. By adopting, the two air cylinders 32 and 42 occupy as compared with the case where the two air cylinders 32 and 42 are arranged (positioned side by side) at positions separated from each other as in the patent application technology of the present applicant. Therefore, the entire fraying prevention device H can be made compact by reducing the plane space to be used, and the fraying prevention device H can be housed in the sewing machine bed portion B.

  In addition, as in the present embodiment, a vertical support shaft 30 is provided on the thread hook 3 in the needle thread retaining mechanism along the thread hook position, the holding position and the standby position together with the thread hook 3. A configuration is adopted in which a looper thread holding body 6 that holds the looper thread extending from the looper 1 to the sewing fabric in front of the lowering position of the needle 2 by swinging in a plane substantially parallel to the needle plate P as the center is adopted. Accordingly, the looper thread 10 can be reliably positioned together with the needle thread 20 while having a simple configuration, whereby the own thread looping can be reliably performed and the fraying prevention effect of the seam can be further ensured. can do.

  In particular, the relative position of the needle thread 20 and the looper thread 10 can be appropriately set by attaching the looper thread holder 6 to the thread hook 3 so that the position thereof can be adjusted. Looping can be performed more reliably, and the fraying prevention effect of the seam can be further enhanced.

  Further, as in the present embodiment, the pin 110 protrudes upward from the connecting end portion 35a of the connecting rod 35, and the pin 110 is connected to the connecting end portion (extension portion 3c) on the thread hook 3 side. By adopting a structure in which a connecting hole 111 that can be inserted into the pin 110 and pulled out from above is formed, adjustment of the sewing tone, repair and replacement of various parts housed in the machine bed B, etc. In order to perform maintenance, when the left throat plate base 11L is fixed to the sewing machine bed B from the upper surface and is removed above the sewing machine bed B, the connecting rod 35 and the extension 3c on the thread hook 3 side No need for troublesome operations such as unscrewing and removing the connecting screw or pulling out the connecting pin, and by simply lifting the left throat plate base 11L upward, the thread hook It is possible to uncoupling a connecting rod 35 and. Further, after the adjustment and maintenance described above, the thread hook 3 and the connecting rod 35 can be returned to a predetermined connected state simply by fixing the left needle plate base 11L to the sewing machine bed B from above. Is possible. As a result, the above-described adjustment and maintenance work can be further simplified.

  In the above embodiment, the hook actuator and the stopper actuator using the air cylinder have been described. However, an electromagnetic solenoid may be used as the actuator.

  Further, in the above embodiment, the description has been given of the case in which the stitches of the double chain stitch are formed by the two needles 20, 20 and the one looper thread 10. However, three or more needle threads are used. Forming multi-needle double chain stitch seams, forming single needle double chain stitch seams using one needle thread, and double chain stitch seams The sewing machine may be applied to an upper decorative double chain stitch sewing machine that performs upper decorative sewing.

  Further, in the above-described embodiment, one needle thread loop of the needle thread loops formed by the two needle threads 20 and 20 is captured and held at the holding position, and one stitch is sewn in this state. Although the description has been given of the case where the yarn is looped and the fraying is stopped by performing the operation, a plurality of needle thread loops may be captured and held in the holding position, and the sewing operation in this holding state is performed by one stitch. It is not limited to minutes, but may be two stitches or more.

In the above-described embodiment, the looper yarn holder 6 is attached to the yarn hook 3 in a state of being fastened together, and both of them 6 and 3 swing together. 6 may be provided separately from the yarn hook 3 and may be operated separately by a dedicated actuator different from the yarn operation cylinder 32 for operating the yarn hook 3.
Furthermore, the installation of the looper yarn holder 6 is not essential.

DESCRIPTION OF SYMBOLS 1 Looper 2 Needle 3 Thread hook 4 Stopper member 6 Looper thread holding body 8 Control part 9 Swing lever 10 Looper thread 11 Needle plate base 11L Left needle plate base part 11R Cylinder mounting base part (right needle plate base part)
20 Needle thread 20a, 20b Needle thread loop 30 Vertical support shaft 32 Thread operation cylinder (hook actuator)
35 Connecting rod (connecting member)
42 Stopper cylinder (Stopper actuator)
91 Spring 92 Swing lever mounting base (movable base)
102 Screw member 103 Knock pin 104 Pin hole 110 Pin 111 Connection hole A Needle drop position B Sewing bed part P Needle plate M Double chain stitch seam H Fray prevention device

Claims (10)

A needle that moves up and down while holding the needle thread, and a needle thread loop that holds the looper thread and can move forward and backward in a direction substantially perpendicular to the vertical movement path of the needle, and the needle forms below the needle plate during the advance operation And a needle plate base attached to the upper surface of the sewing machine bed portion, and a needle thread loop formed under the needle plate by the needle is captured by the looper. A double chain stitch sewing machine that forms double chain stitch stitches on a sewing fabric by looping the needle thread with another looper thread held by the looper,
In a plane that is capable of approaching and moving away from the looper, and that is substantially parallel to the needle plate about a vertical support shaft between a standby position separated from the looper and a thread hooking position approaching the looper. A needle thread holding mechanism having a thread hook that swings and a hook actuator that drives and swings the thread hook to the standby position and the thread hook position;
A needle thread loop that is disposed at a position farther from the needle plate than the thread hook of the needle thread holding mechanism and is captured by the thread hook at the thread hook position is between the thread hook position and the standby position. A stopper member that can temporarily stop and release the swing of the yarn hook from the yarn hooking position to the standby position, and a stopper actuator that controls the stop and stop release of the stopper member A stopper mechanism having,
A connecting member for interlockingly connecting a thread hook of the needle thread holding mechanism and a stopper member of the stopper mechanism;
After the normal sewing is finished, the looper is moved forward, and the needle thread loop thread caught at the thread hooking position by moving the thread hook of the needle thread holding mechanism closer to the looper is held at the holding position. The needle thread holding mechanism and the stopper mechanism are associated with the needle vertical movement, the looper advance / retreat operation, and the sewing fabric feed operation so that the sewing operation can be performed for at least one stitch while maintaining this state. A double chain stitch sewing machine with a fraying prevention device for stitches,
The needle plate base includes a left needle plate base portion to which the needle plate is attached and which supports a swing support shaft of the thread hook, and a right needle plate that fixedly supports the stopper member, the hook actuator, and the stopper actuator. It is divided into two parts:
The right needle plate base is fixed to the sewing machine bed, and the left needle plate base is attached to the upper surface of the sewing machine bed via a screw member so as to be fastened and fixed. A double chainstitch sewing machine with a fray-stop device for seams.   The stopper mechanism includes a stopper member that is directly connected to the hook actuator and linearly reciprocates, a swing lever that can be engaged with and released from a part of the stopper member, and the swing lever that is threaded. A spring that swings and biases the hook in a direction in which the hook is located at the standby position; and a stopper actuator that disengages the swing lever from a part of the stopper member against the biasing force of the spring. The double chain stitch sewing machine with a fray prevention device for a seam according to claim 1. 3. The double chain stitch sewing machine with a fray preventing device for a stitch according to claim 2 , wherein the swing lever in the stopper mechanism is attached to a movable base that is attached to the right needle plate base so as to be adjustable in the left-right position.   The hook actuator of the needle thread holding mechanism and the stopper actuator of the stopper mechanism are fixedly supported on the lower surface of the right needle plate base portion in a state of being vertically stacked in two stages. Double chainstitch sewing machine with fraying prevention device for seams described.   The thread hook of the needle thread holding mechanism swings in a plane substantially parallel to the needle plate about the support shaft between the thread hook, the thread hooking position, the holding position, and the standby position. The looper thread holding body for holding the looper thread extending from the looper to the sewing fabric on the front side of the lowering position of the needle is attached to the stitch according to any one of claims 1 to 4. Double chain stitch sewing machine with anti-fray device.   6. The double chain stitch sewing machine with a seam fray preventing device according to claim 5, wherein the looper thread holding body is attached to the thread hook so as to be adjustable in position.   The double chain stitch sewing machine with a fray preventing device for a stitch according to any one of claims 1 to 4, wherein both the hook actuator of the needle thread holding mechanism and the stopper actuator of the stopper mechanism are air cylinders.   A pin protrudes upward from the connection end portion at the connection end portion of the connection member, and the connection end portion of the thread hook is inserted into the pin from above the pin and pulled out upward. The double chain stitch sewing machine with a fraying preventing device for a seam according to any one of claims 1 to 7, wherein a possible connecting hole is formed.   On the left throat plate base or the machine bed portion, knock pins that can position the left throat plate base with respect to the machine bed portion protrude from a plurality of fixed connection and connection release locations by the screw member. The stitch fraying prevention device according to any one of claims 1 to 8, wherein a pin hole that can be fitted to the knock pin is formed in the sewing bed portion or the left needle plate base portion. Double chainstitch sewing machine with device.   The double chain stitch sewing machine with a fray preventing device for a stitch according to any one of claims 1 to 9, wherein the target sewing machine is a horizontal cylindrical double chain stitch sewing machine.

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