Abstract: A threading device of a sewing machine includes a thread inserting base formed with a thread path hole having a thread inserting port opened toward an outer side of a sewing machine frame, and further formed with an air path hole which joins the thread path hole in the vicinity of the thread inserting port, an air supply device coupled to the air path hole to supply compressed air, and illuminating means provided on the sewing machine frame to irradiate a joining portion of the thread path hole and the air path hole. The thread inserting base includes a transparent member through which at least the joining portion of the thread path hole and the air path hole can be visually recognized.

Abstract: A sewing machine includes an upper looper formed with a thread hole, an upper looper shaft which oscillates the upper looper between an upper position and a lower position, switching means operable to switch a coupled state and a decoupled state between the upper looper and the upper looper shaft, moving means for moving the upper looper, which has been decoupled from the upper looper shaft by the switching means, to the lower position, a thread guiding pipe formed with a thread discharging port, and first operating means operable to decouple the upper looper and the upper looper shaft via the switching means, and to move the thread discharging port of the thread guiding pipe to a position at which the thread discharging port is aligned with the thread hole of the upper looper in the lower position.

Abstract: A sewing machine includes a looper formed with a thread hole, a looper shaft holding the looper, and a thread pipe fixed to the looper shaft. The thread pipe includes a thread inserting port at one end and a thread discharging port at the other end. The sewing machine further includes a nozzle from which air is sprayed toward the thread inserting port, a switching mechanism operable to disconnect the looper from the looper shaft when the looper is at a front position, and a moving member which moves the looper to a rear position when the looper is disconnected from the looper shaft by the switching mechanism. When the looper is disconnected from the looper shaft and is moved to the rear position, the thread discharging port matches the thread hole, and the thread inserting port becomes close to the nozzle.

Abstract: A lower end of a thread guide lever, which is rockably attached to a lower looper and supports a thread pipe, and an air ejecting unit, which faces a thread inserting hole of the thread pipe and ejects air toward the thread inserting hole, are coupled via a coupling member so that they are interlocked with each other. The coupling member is moved such that a discharging port of an air nozzle is positioned at an ejecting position close to the thread inserting hole when a thread discharging hole is positioned at a threading position which is coincident with a thread hole of a lower looper, and such that the air nozzle is moved to a standby position when the thread discharging hole is moved to a retreating position.

Abstract: A threading device of a sewing machine includes a thread inserting base formed with a thread path hole having a thread inserting port opened toward an outer side of a sewing machine frame, and further formed with an air path hole which joins the thread path hole in the vicinity of the thread inserting port, an air supply device coupled to the air path hole to supply compressed air, and illuminating means provided on the sewing machine frame to irradiate a joining portion of the thread path hole and the air path hole. The thread inserting base includes a transparent member through which at least the joining portion of the thread path hole and the air path hole can be visually recognized.

Abstract: A sewing machine includes an upper looper formed with a thread hole, an upper looper shaft which oscillates the upper looper between an upper position and a lower position, switching means operable to switch a coupled state and a decoupled state between the upper looper and the upper looper shaft, moving means for moving the upper looper, which has been decoupled from the upper looper shaft by the switching means, to the lower position, a thread guiding pipe formed with a thread discharging port, and first operating means operable to decouple the upper looper and the upper looper shaft via the switching means, and to move the thread discharging port of the thread guiding pipe to a position at which the thread discharging port is aligned with the thread hole of the upper looper in the lower position.

Abstract: A sewing machine includes a looper formed with a thread hole, a looper shaft holding the looper, and a thread pipe fixed to the looper shaft. The thread pipe includes a thread inserting port at one end and a thread discharging port at the other end. The sewing machine further includes a nozzle from which air is sprayed toward the thread inserting port, a switching mechanism operable to disconnect the looper from the looper shaft when the looper is at a front position, and a moving member which moves the looper to a rear position when the looper is disconnected from the looper shaft by the switching mechanism. When the looper is disconnected from the looper shaft and is moved to the rear position, the thread discharging port matches the thread hole, and the thread inserting port becomes close to the nozzle.

Abstract: A darning width adjusting device for a sewing machine includes a lower knife holder supported by a sewing machine frame such that a moving position of the lower knife holder is adjustable in a direction orthogonal to a cloth feeding direction, a thread-sliding piece which sets a darning width by picking up a thread at a tip thereof in the vicinity of a stitch point, a thread-sliding piece holder supported by the sewing machine frame such that a moving position of the thread-sliding piece is adjustable in the orthogonal direction to the cloth feeding direction, a thread-sliding piece adjusting means for adjusting the moving position of the thread-sliding piece, and a lower knife holder adjusting means for adjusting the moving position of the lower knife holder to a position exceeding a outside marginal position of the thread-sliding piece.

Abstract: A darning width adjusting device for a sewing machine includes a lower knife holder supported by a sewing machine frame such that a moving position of the lower knife holder is adjustable in a direction orthogonal to a cloth feeding direction, a thread-sliding piece which sets a darning width by picking up a thread at a tip thereof in the vicinity of a stitch point, a thread-sliding piece holder supported by the sewing machine frame such that a moving position of the thread-sliding piece is adjustable in the orthogonal direction to the cloth feeding direction, a thread-sliding piece adjusting means for adjusting the moving position of the thread-sliding piece, and a lower knife holder adjusting means for adjusting the moving position of the lower knife holder to a position exceeding a outside marginal position of the thread-sliding piece.

Abstract: A cloth cutting knife driving device is capable of being released, through an interlocking connection between an upper knife rocking arm and a sewing machine main shaft. The device includes a drive shaft, which is able to swing rotatably, by interlocking with a main shaft, a rocking arm rotatably supported on the drive shaft at one end providing a rocking motion, and a cloth cutting knife supported at the one end of the rocking arm that is rigidly held in a cloth cutting position or an inactive position, which is vertically displaced through the motion of the arm. The device has a coupled and released state between the drive shaft and rocking arm, which are brought about by an engaging part on the drive shaft and a movable member, movable relative to the rocking arm in a direction perpendicular to an axis of the drive shaft.

Abstract: A chain stitch sewing machine comprises a needle for penetrating through a cloth on a throat plate to be vertically moved interlockingly with a main spindle of the sewing machine, thereby holding a needle thread, a cloth presser mounted on the throat plate and serving to press the cloth, a looper having a looper thread for reciprocating in such a direction as to cross a cloth feeding direction below the throat plate interlockingly with the main spindle of the sewing machine, a main feed dog for feeding a loop formed by the needle thread and the looper thread in cooperation of the needle and the looper rearward in the cloth feeding direction, and a loop engagement member for protruding from an upper surface of the throat plate and engaging the loop with the cloth presser when the main feed dog is descending from the upper surface of the throat plate.

Abstract: Disclosed is a chainstitch sewing machine having a plurality of needles having needle threads which are moved up and down through needle holes of a throat plate, a looper having a looper thread, which is reciprocatively moved in a direction orthogonal to a cloth feeding direction under the throat plate, guide holes provided in the throat plate for guiding loops formed by the needle threads and a looper thread by the cooperation of the needles and the looper, to a rear part in a cloth feeding direction, and a main feed dog, disposed at a part closer to a rear than the guide hole, for feeding the loops in the cloth feeding direction.

Abstract: A chain stitch sewing machine comprises a needle for penetrating through a cloth on a throat plate to be vertically moved interlockingly with a main spindle of the sewing machine, thereby holding a needle thread, a cloth presser mounted on the throat plate and serving to press the cloth, a looper having a looper thread for reciprocating in such a direction as to cross a cloth feeding direction below the throat plate interlockingly with the main spindle of the sewing machine, a main feed dog for feeding a loop formed by the needle thread and the looper thread in cooperation of the needle and the looper rearward in the cloth feeding direction, and a loop engagement member for protruding from an upper surface of the throat plate and engaging the loop with the cloth presser when the main feed dog is descending from the upper surface of the throat plate.

Abstract: A cloth cutting knife driving device is capable of being released, through an interlocking connection between an upper knife rocking arm and a sewing machine main shaft. The device includes a drive shaft, which is able to swing rotatably, by interlocking with a main shaft, a rocking arm rotatably supported on the drive shaft at one end providing a rocking motion, and a cloth cutting knife supported at the one end of the rocking arm that is rigidly held in a cloth cutting position or an inactive position, which is vertically displaced through the motion of the arm. The device has a coupled and released state between the drive shaft and rocking arm, which are brought about by an engaging part on the drive shaft and a movable member, movable relative to the rocking arm in a direction perpendicular to an axis of the drive shaft.

Abstract: Disclosed is a chainstitch sewing machine having a plurality of needles having needle threads which are moved up and down through needle holes of a throat plate, a looper having a looper thread, which is reciprocatively moved in a direction orthogonal to a cloth feeding direction under the throat plate, guide holes provided in the throat plate for guiding loops formed by the needle threads and a looper thread by the cooperation of the needles and the looper, to a rear part in a cloth feeding direction, and a main feed dog, disposed at a part closer to a rear than the guide hole, for feeding the loops in the cloth feeding direction.

Abstract: An upper decorative stitching spreader 11 is switched active or inactive by an upper decoration switching mechanism 25. By placing the spreader 11 in active state, upper decorative stitches which are formed from above the fabric are added to the conventional over-edge chain stitches and lower decorative stitches which are formed from below the fabric. On the other hand, by placing the spreader 11 in an inactive state; that is, by stopping the spreader 11, over-edge chain stitching without upper decorative stitching, and lower decorative stitching which is performed from below the fabric are performed without interference with the spreader 11.