JP4310289B2 - Chain stitch sewing machine - Google Patents

Description

  The present invention relates to a chain stitch sewing machine capable of performing multicolor chain stitching by selectively using a plurality of sewing threads having different colors and properties with a single looper. In particular, the present invention relates to a chain stitch sewing machine that is suitable for performing chain stitch on a tubular workpiece.

Conventionally, a reed-driven reed needle and a looper arranged to supply a sewing thread below the needle plate cooperate with each other, and the looper is rotationally controlled synchronously with the sewing operation of the reed needle. A chain stitch sewing machine that performs chain stitch on a workpiece is known. Also, one sewing machine head (also referred to as a sewing head) is provided with one looper, and a plurality of sewing threads having different colors and properties are prepared for this single looper. Also known is a chain stitch sewing machine in which chain stitches (that is, multicolor chain stitches) using multi-colored threads are applied to a sewing object by selectively inserting a thread through the looper. As an example of a chain stitch sewing machine capable of performing multi-color chain stitching by selectively using a plurality of such sewing threads with a single looper, a ring disclosed in Patent Document 1 or Patent Document 2 shown below is used. There are sewing machines. In a conventional chain stitch sewing machine as disclosed in the following Patent Document 1 or Patent Document 2, in order to selectively supply any one of a plurality of sewing threads to the looper, A laterally slidable thread supply mechanism is arranged. In this thread supply mechanism, a plurality of sewing threads are set in parallel along the slide direction, and the thread supply mechanism is slid so that a desired sewing thread is appropriately positioned directly below the looper, and in this state, the air The sewing thread is changed in color by inserting the sewing thread located immediately below the looper through the injection of the looper into the looper.
Japanese Patent No. 3457040 JP 2002-317374 A

  As described above, the conventional chain stitch sewing machine changes the color of the sewing thread by sliding the thread supply mechanism in which a plurality of sewing threads are set in parallel. Therefore, the sewing machine is applied only to a planar sewing product. It was something that could not be done. On the other hand, there are also cylindrical sewing objects such as T-shirts and hats. As is well known, in order to perform normal sewing or embroidery on a cylindrical sewing product, it is necessary to position a cylindrical hook bed with a built-in hook inside the cylindrical sewing product. Similarly to this, in order to carry out chain stitching on a cylindrical sewing product, it is necessary to position a looper inside the cylindrical sewing product. However, in the conventional chain stitch sewing machine capable of changing the color of the sewing thread by arbitrarily inserting a plurality of threads into a single looper, the sliding direction of the thread supply mechanism that can slide in the lateral direction Since the plurality of sewing threads are arranged linearly in parallel with each other, the thread supply mechanism has a lateral width corresponding to the number of sewing threads. In order to carry out chain stitching on a cylindrical workpiece with such a conventional chain stitching device, a thread supply mechanism having a lateral width corresponding to a plurality of sewing threads is positioned inside the cylindrical workpiece with a looper. It is also necessary to allow the thread supply mechanism to slide. For this reason, the cylindrical sewing product that can be chain-sewn is not limited to a considerably large size, but is a large-size sewing product that can be chain-sewn. However, the sewing range is extremely limited, and the practicality is poor. Accordingly, in the past, there has been no chain stitch sewing machine suitable for performing a chain stitch (multicolor chain stitch) with a multicolor thread on a tubular workpiece.

  The present invention has been made in view of the above points, and in a chain stitch sewing machine having one looper corresponding to one sewing machine head, a desired sewing thread is sewn to the looper from a plurality of sewing threads. An object of the present invention is to provide a chain stitch sewing machine having a compact thread supply mechanism that selectively supplies a possible state. Another object of the present invention is to provide a chain stitch sewing machine suitable for chain stitching with a multi-colored thread on a cylindrical workpiece.

  A chain stitch sewing machine according to the present invention includes a reed-driven reed needle, a looper disposed below a needle plate and driven to rotate in synchronization with a sewing operation, and any one of a plurality of thread supply ports. A connecting member that is selectively driven to be connected to the threading port of the thread, and a thread of one thread supply port that is connected to the threading port of the looper via the connecting member. And a mechanism for inserting the looper through the threading port of the looper so that the sewing work can be performed, and performing the chain stitch by the cooperation of the looper through which the sewing thread is inserted in the sewing workable state and the hook needle. Features.

  According to this, the connecting member having one yarn passage is selectively driven to connect any one of the plurality of yarn supply ports to the threading port of the looper, and the yarn of the looper is connected via the connecting member. By inserting the thread of one thread supply port leading to the threading port into a state in which sewing can be performed with respect to the threading port of the looper, a plurality of different colors and properties with respect to a single looper The whole thread supply mechanism for selectively supplying the sewing thread and the looper can be configured to be housed in a looper base having a shape in which one end protrudes, and from this one end, the cylindrical sewing product Therefore, it is possible to provide a chain stitch sewing machine suitable for performing a chain stitch on a cylindrical workpiece. In addition, since the structure of the thread supply mechanism itself can be simplified, the present invention can be advantageously applied not only to a cylindrical sewing product but also to a sewing machine that performs chain stitching on a flat sewing product.

  As a preferred embodiment of the present invention, the plurality of yarn supply ports are arranged in an arc shape, and the connecting member is driven to rotate, so that any one of the plurality of yarn supply ports is connected to the yarn of the looper. It is connected to a through hole. As a result, the mechanism for supplying the sewing thread to the threading port of the looper can be made smaller, and the sewing thread can be changed in color without requiring a large drive configuration such as sliding the whole. The present invention can be advantageously applied to a sewing machine that performs chain stitching on a cylindrical sewing product.

  According to the present invention, by selectively connecting any one of the plurality of thread supply ports to the threader opening of the looper by the connecting member, the sewing thread is switched for a single looper. The thread supply mechanism of the sewing thread can be configured more compactly than before, and this provides an excellent chain stitch sewing machine that is suitable for performing multi-color chain stitching on a cylindrical sewing product. There is an effect.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is an external view of a multi-head chain stitch sewing machine according to an embodiment of the present invention, which includes a plurality of chain stitch sewing heads 3. 1 is a sewing machine frame, 2 is a table, and the table 2 has a front table 2a that can be raised and lowered. On the front surface of the sewing machine frame 1, a plurality of (four in the illustrated example) sewing machine heads 3 for sewing with a well-known structure are arranged, and each sewing machine head 3 is reciprocated up and down. 4 (see FIG. 7 described later). A cylindrical looper base (looper part) 5 is arranged below each sewing machine head 3. A non-illustrated base sash frame that is moved in the X / Y direction is disposed on the table 2, and a pair of left and right support arms 6 are provided on the base sash frame corresponding to each sewing head 3. . The pair of support arms 6 supports a sewing frame 7 on which a cylindrical sewing object H such as a body of a T-shirt is set. The looper base 5 has a so-called cylindrical shape (cylinder shape or rod shape) in which the front end protrudes into the space so that it can enter the inside of the cylindrical sewing object H set on the sewing frame 7. The base portion (one end near the back) is fixed to the sewing machine frame 1 and has a cantilever support structure.

  Next, the internal structure of the looper base 5 will be described in detail. FIG. 2 is a side view of the looper base 5 according to the same embodiment as viewed from the front side of the sewing machine shown in FIG. 1, and FIG. 3 is a side sectional view of the looper base 5. In FIGS. 2 and 3, the front end portion that protrudes into the space is illustrated on the left, and the base portion (one end on the back) fixed to the sewing machine frame 1 is positioned on the right. FIG. 4 is a top view of the looper base 5, and FIG. 5 is a bottom view of the looper base 5. FIG. 6 is a front view of the looper base 5 as seen from the front of the sewing machine shown in FIG. As apparent from FIGS. 2 and 5, the base 8 of the looper base 5 is fixed to the sewing machine frame 1 by four stud bolts 9. A plurality of covers are provided above and below the base 8, and the looper base 5 is formed so as to cover the whole with these covers. 2, 4, 5, and 6 show the looper base 5 with the covers removed for easy understanding of the explanation (in the drawings, the covers are imaginary lines). ).

  As shown mainly in FIG. 2, FIG. 3, FIG. 4, FIG. 5, etc., a looper R is disposed at the tip of the base 8 (left side of FIG. 2 and FIG. 3, lower side of FIG. 4 and FIG. 5). The looper R is rotatably supported by a base 8 and a support member 10 fixed below the base 8 so as to have a predetermined distance. A pulley portion Ra is formed on the outer periphery of the looper R. On the other hand, a motor 14 is fixedly installed at the base of the base 8 (the right side of FIGS. 2 and 3, the upper side of FIGS. 4 and 5), and a drive pulley 15 is fixed to the motor shaft of the motor 14. It is. A bearing member 13 is provided in front of the intermediate position between the tip and base of the base 8, and the bearing member 13 includes a large-diameter pulley 12 a and a small-diameter pulley 12 b that are arranged vertically with the base 8 interposed therebetween. The intermediate pulley 12 is rotatably supported. A timing belt 16 is stretched between the pulley portion Ra of the looper R and the large-diameter pulley 12a of the intermediate pulley 12, while between the small-diameter pulley 12b of the intermediate pulley 12 and the drive pulley 15 of the motor 14. A timing belt 17 is stretched over. According to such a configuration, as the driving pulley 15 is rotated by driving the motor 14, the rotation is transmitted to the small-diameter pulley 12b by the timing belt 17, and is fixed to the common shaft with the small-diameter pulley 12b. The diameter pulley 12a is rotated. Further, as the large-diameter pulley 12a rotates, the rotation is transmitted to the pulley portion Ra by the timing belt 16. In this way, the looper R can be finally driven to rotate by the rotational force transmitted from the motor 14.

  FIG. 7 is an enlarged side sectional view showing a side section of the looper base 5 shown in FIG. FIG. 8 is a perspective view showing a part of the configuration in the tip of the looper base 5 according to the embodiment. As apparent from FIG. 7, the looper R has a threading hole 11 penetrating vertically so that the sewing thread T can pass therethrough. The threading hole 11 is bent at the middle portion as shown in the figure, and is formed so as to lead out the sewing thread T inserted from the thread insertion port 11a which is the opening at the lower end from the opening Rb at the upper end. . That is, the threading hole 11 is formed such that the thread insertion opening 11a, which is an opening at the lower end, is formed at the rotation center position of the looper R, and the upper end opening Rb on the opposite side is formed at a position eccentric from the rotation center of the looper R. The shape is bent at the part. A yarn outlet tube 45 is erected at the upper end opening Rb, and the upper end thereof serves as a yarn outlet 11b. The thread outlet 11b guides the sewing thread T toward the needle hole 43a that allows the needle needle 4 of the needle plate 43 fixed to the bracket 34 to pass therethrough. As is well known, the looper R is driven to rotate as described above with the hook 4 lowered and its hook (not shown) positioned in the needle hole 43a, so that it is led out from the thread outlet 11b. The sewn thread T is wound around the heel needle 4, and then the heel needle 4 is raised and the wound thread T is hooked by the heel portion and pulled out on the surface of the sewing product, so that the chain stitch is performed. The sewing thread T is fed from a plurality of thread spools arranged in a thread stand (not shown), and any one of the sewing threads T fed from the plurality of thread spools selectively enters the threading hole 11 of the looper R. (The details will be described later).

  As shown in FIGS. 3 and 5, the shaft 18 is rotatably supported by a bearing 19 fixed to the bottom surface of the base 8 and a bracket 20 fixed to the bottom surface of the support member 10. A driven gear 21 is fixed to the rear end portion of the shaft 18, and the driven gear 21 meshes with a drive gear 22 positioned below. The drive gear 22 is fixed to a slide shaft 23 that is slidably driven in the left-right direction in accordance with a color change command for the sewing thread T to the chain stitch sewing machine. Both the drive gear 22 and the driven gear 21 are spiral gears. Accordingly, the shaft 18 is rotationally driven via the drive gear 22 and the driven gear 21 in accordance with the slide drive of the slide shaft 23. As shown in FIGS. 5, 6, 8, or the like, a plurality of (9 in the illustrated example) guide tubes 24 are arranged in an arc shape centered on the axis of the shaft 18. Each guide tube 24 is configured such that a sewing thread T fed from a plurality of thread spools arranged in a thread stand device (not shown) can be set from the rear end portion toward the front end portion. The tip of each guide tube 24 is supported by a bracket 20, and the bracket 20 has a plurality of thread supply ports serving as outlets of the sewing thread T set in each guide tube 24 so as to correspond to each guide tube 24. is doing. On the other hand, the rear portion of each guide tube 24 is bent and the rear end portion is formed substantially vertically downward. The rear end of each guide tube 24 is fixed in series in the left-right direction to a guide member 26 fixed to the sewing machine frame 1, and the unillustrated thread disposed at a predetermined position below the guide member 26. The sewing thread T fed out from the standing device is drawn into each guide tube 24 from the rear end portion. Further, the front portion of the bent portion of each guide tube 24 is supported by a support member 25.

  The connecting member 27 is fixed to the tip of the shaft 18 that is rotatably supported on the bottom surface of the base 8 as described above. As is apparent from FIGS. 7 and 8, the connecting member 27 has one inclined connecting hole 27a (yarn passage), and has a connecting portion 27b at the tip thereof. The connecting hole 27a (yarn passage) has a front end portion (left side in FIG. 7) at a position on the extension of the axis of the shaft 18, and a rear end portion (right side in FIG. 20 thread supply ports). As a result, the connecting member 27 is rotated at a predetermined angle (pitch) along with the rotation of the shaft 18 as described above, and the connecting hole 27a (yarn passage) of the connecting member 27 is supported by the bracket 20 at the tip thereof. The guide pipes 24 can be selectively connected to the guide pipes 24 in sequence, and in response to this, one thread passage through which the sewing thread T passes is formed with one of the guide pipes 24.

  An air supply block 28 is fixed to the bottom surface of the support member 10. As is apparent from FIGS. 7 and 8, the nozzle 29 is fixed to the air supply block 28, and the air supply block is located at a position where the linkage portion 27 b of the connecting member 27 enters the rear end portion of the nozzle 29. 28 and the connecting member 27 are arranged with each other. A connecting pipe 30 is fixed to the tip of the nozzle 29, and the upper end of the connecting pipe 30 faces the thread insertion port 11a of the looper R almost closely. FIG. 9 is a plan sectional view of the air supply block 28. A connector 31 is fixed to the air supply block 28, and a tube 32 from an air supply source (not shown) is connected to the connector 31. As a result, air is supplied from the air supply source into the air supply block 28. When air is supplied to the air supply block 28, the air flows into the annular space 28b formed between the nipple portion 29a of the nozzle 29 and the air supply block 28 through the air passage 28a, and further the outer periphery of the nipple portion 29a. From the threaded portion toward the inside of the connecting pipe 30 and is discharged from the thread outlet 11b of the threading hole 11. For this reason, the inside of the nipple portion 29a becomes a negative pressure, and the suction force of the yarn is generated. That is, if the shaft 18 is rotated to connect the connecting hole 27a of the connecting member 27 to the guide tube 24 through which the desired sewing thread T is passed, and the air is supplied from the air supply source, the desired sewing thread T becomes the looper R. Is inserted into the threading hole 11. In this way, a supply path of a series of sewing threads T that continues from the thread stand device (not shown) to the guide tube 24 (the thread supply port of the bracket 20), the connecting hole 27a of the connecting member 27, and the threading hole 11 of the looper R. Is to be formed.

  As shown in FIG. 4, a movable blade 33 is rotatably supported on a bracket 34 fixed to the upper surface of the base 8. The movable blade 33 has a connecting arm 33 a, and the connecting arm 33 a is connected to a lever 36 via a connecting plate 35. The lever 36 is fixed to the upper end of a shaft 37 that is pivotally supported by the base 8, and a drive arm 38 is fixed to the lower end of the shaft 37 as shown in FIG. The distal end of the drive arm 38 is connected to the fixed block 40 via a connecting eye 39. The fixed block 40 is fixed to a slide shaft 41 that is slidably driven in the left-right direction in response to a thread trimming command to the chain stitch sewing machine. Thereby, if the slide shaft 41 is slid, the movable blade 33 will be rotated. A fixed blade 42 is fixed to the side surface of the bracket 34, and the sewing thread T is cut by the fixed blade 42 and the movable blade 33 that is rotated. That is, at the time of sewing, the movable blade 33 is in a rotational position indicated by a solid line in FIG. 4, that is, a position that does not have any influence on the sewing thread T derived from the looper R. As the cutting operation of the sewing thread T, first, the movable blade 33 is rotated clockwise (in FIG. 4) to a position where the sewing thread T can be captured on the fixed blade 42 side. Next, the movable blade 33 is rotated counterclockwise, the sewing thread T is captured, and the movable blade 33 returns to the rotation position indicated by the solid line in FIG. At this time, the movable blade 33 and the fixed blade 42 mesh with each other, and the sewing thread T is cut. At this time, the thread end of the cut sewing thread T on the looper R side is held by a holding member (not shown). The holding of the thread end of the sewing thread T on the looper R side is released by rotating the movable blade 33 clockwise by a certain amount.

  A thread handing device for handing a thread end of the sewing thread T inserted through the looper R (having been sewn up to now) so as to be positioned in the guide pipe 24 below the rear end portion of each guide pipe 24. Is provided. As such a yarn handing device, for example, a pulling-down member described in Japanese Patent Application Laid-Open No. 2002-317374 related to the applicant's application, an increasing means for increasing the pulling-down amount of the yarn, and the like may be used. Since these are publicly known, description thereof is omitted here. Of course, it goes without saying that the present invention is not limited to the above.

  Next, in the chain stitch sewing machine according to the present invention having the above-described configuration, the operation when performing chain stitch on a tubular workpiece will be described. In each guide tube 24, sewing threads T having different colors and properties fed from a plurality of thread spools arranged in a thread stand device (not shown) are set. When starting the chain stitching, first, the shaft 18 is rotated to connect the connecting hole 27a of the connecting member 27 to any of the guide pipes 24 on which the desired sewing thread T is set. When air is supplied from the air supply source to the air supply block 28 in this state, the sewing thread T set in the guide tube 24 connected by the supplied air is inserted into the threading hole 11 of the looper R, and the sewing thread T The yarn end is led out from the yarn outlet 11b. Then, the movable blade 33 is rotated from the thread outlet 11b through the connecting hole 27a of the connecting member 27, the connecting pipe 30 of the air supply block 28, and the threading hole 11 of the looper R by rotating the movable blade 33 in the same manner as when cutting the thread. The thread end of the sewing thread T is held.

  When the thread end of the sewing thread T is held, the motor 14 is driven to rotate the looper R and the needle 4 of the sewing machine head 3 is moved up and down. Further, the sewing frame 7 on which the cylindrical sewing product H is set is moved in the X / Y direction so as to be synchronized with these operations. In this way, a chain stitch such as a pattern or embroidery by a desired sewing thread T is performed on the workpiece H.

  When changing the sewing thread T for chain stitching, the rotation of the looper R and the vertical movement of the heel needle 4 are stopped, and then the movable blade 33 is sequentially rotated clockwise and counterclockwise to cut the sewing thread T. When the sewing thread T is cut, the movable blade 33 is further rotated by a certain amount in the clockwise direction to release the holding of the thread end of the sewing thread T on the looper R side. Then, the sewing thread T inserted through the looper R is manually fed by a thread handling device (not shown), and the thread end on the looper R side of the sewing thread T released from the holding is positioned in the guide tube 24. Next, the shaft 18 is rotated to connect the connecting hole 27a of the connecting member 27 with the guide tube 24 on which the next desired sewing thread T is set, and air is supplied to the air supply block 28 so that the sewing thread T is looped through the looper R. Then, the movable blade 33 is rotated to hold the thread end of the sewing thread T inserted into the looper R. Then, in the same manner as described above, the looper R is rotated and the heel needle 4 is moved up and down to carry out chain stitching with the desired sewing thread T on the workpiece H. As is known, chain stitch types include chain stitching, loop stitching, and the like, which can be switched according to the setting of the sewing operation.

  As described above, according to the chain stitch sewing machine shown in the above embodiment, a plurality of threads are guided to the vicinity of the looper R by the guide pipe 24, and the thread of each guide pipe 24 and the looper R is rotated by the rotation of the connecting member 27. Since the insertion hole 11 is configured to be connectable, a member positioned below the looper R can be made very small, and the looper base 5 can be formed into a narrow cylindrical shape. Thereby, it can position on the inner side of various kinds of cylindrical sewing objects H. Further, when the sewing thread T is changed, only the small bulky connecting member 27 is rotated, so that not only the drive source can be reduced in size but also the color change can be performed at a high speed.

In the above embodiment, air from the air supply source is supplied only to the air supply block 28 so that the sewing thread T set in the connected guide tube 24 is inserted into the threading hole 11 of the looper R. However, the present invention is not limited thereto, and the movement of the sewing thread T in the guide tube 24 may be assisted by supplying air also to the vicinity of the rear end portion of the guide tube 24.
The sewing thread T is guided to the vicinity of the looper R, and the threading port of the looper R and the end of the guide tube 24 are selectively connected by the connecting member 27, so that a plurality of sewing threads are connected to the single looper R. It is not always necessary to be able to locate the inside of the cylindrical sewing product H. In other words, the present invention may be applied to a sewing machine that sews a flat workpiece.

The arrangement of the guide tube 24 for guiding the sewing thread T to the vicinity of the looper R and the arrangement of the plurality of thread supply ports of the bracket 20 are not limited to the arcuate arrangement around the axis of the shaft 18, for example, in parallel. You may arrange. However, in such a case, in order to connect the connecting hole 27a of the connecting member 27 to each guide tube 24, it goes without saying that the connecting member 27 is driven not to rotate but to move in parallel.
The guide tube 24 is not limited to a tubular one, and any guide tube 24 may be used as long as it can guide the sewing thread T to the bracket 20.
As is well known, the sewing frame 7 is driven in the X / Y direction in accordance with the sewing pattern data. However, the sewing frame 7 is not limited to the planar X / Y drive, and is not limited to rotation such as embroidery sewing of a hat. It may include driving. Moreover, the structure which moves the sewing machine head 3 and the looper base 5 according to a sewing pattern may be sufficient.

1 is an external view of a multi-headed chain stitch sewing machine according to an embodiment of the present invention. It is the side view which looked at the looper base from the right toward the front of the said sewing machine shown in FIG. It is a sectional side view of a looper base. It is a top view of a looper base. It is a bottom view of a looper base. It is the front view which looked at the looper base from the front of the said sewing machine shown in FIG. It is the figure which expanded and showed the side sectional view similar to FIG. 3 about the front-end | tip part. It is a perspective view which extracts and shows a part of structure in the front-end | tip part of the looper base which concerns on the Example. It is a plane sectional view of an air supply block.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sewing machine frame, 2 ... Table, 2a ... Front table, 3 ... Sewing head for chain stitches, 4 ... Acupuncture needle, 5 ... Looper base (looper part), 6 ... Support arm, 7 ... Sewing frame, 8 ... Base, 9 ... Stud bolt, 10 (25) ... Support member, 11 ... Threading hole, 11a ... Thread insertion port, 11b ... Thread outlet, 12 ... Intermediate pulley, 12a ... Large diameter pulley, 12b ... Small diameter pulley, 13 ... Bearing member , 14 ... motor, 15 ... drive pulley, 16 (17) ... timing belt, 18 ... shaft, 19 ... bearing, 20 ... bracket, 21 ... driven gear, 22 ... drive gear, 23 ... slide shaft, 24 ... guide tube, 26 ... Guide member, 27 ... Connecting member, 27a ... Connecting hole, 27b ... Linking portion, 28 ... Air supply block, 28a ... Air passage, 28b ... Annular space, 29 ... Nozzle, 29a ... Nipple portion, DESCRIPTION OF SYMBOLS 0 ... Connecting pipe, 31 ... Connector, 32 ... Tube, 33 ... Movable blade, 34 ... Bracket, 35 ... Connecting plate, 36 ... Lever, 37 ... Shaft, 38 ... Drive arm, 39 ... Connection eyepiece, 40 ... Fixed block , 41 ... Slide shaft, 42 ... Fixed blade, 43 ... Needle plate, 44 ... Needle needle, 45 ... Thread outlet tube, H ... Sewing object, R ... Looper, Ra ... Pulley part, Rb ... Upper end opening, T ... Sewing thread

Claims (2)

A reciprocating needle,
A looper disposed below the needle plate and driven to rotate in synchronization with the sewing operation;
A connecting member having one yarn passage selectively driven to connect any one of a plurality of yarn supply ports to a threading port of the looper;
A mechanism for inserting a thread of one thread supply port that is passed through the threading port of the looper through the connecting member into a state in which sewing can be performed with respect to the threading port of the looper;
A chain stitch sewing machine, wherein a chain stitch is performed by cooperation of a looper through which a sewing thread is inserted in a state where the sewing operation is possible and the heel needle.   The plurality of yarn supply ports are arranged in an arc shape, and the connecting member is rotationally driven to connect any one of the plurality of yarn supply ports to the threading port of the looper. The chain stitch sewing machine according to claim 1.

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