Abstract: A thread tension adjusting apparatus, used in a sewing machine, adjusts tension of a supplied thread by adjusting a thread holding force. The apparatus is provided on a thread supply path running from a thread source to a thread processing section such as a needle and a looper. The thread tension adjusting apparatus comprises a pair of members respectively having portions opposed to each other. At least one of the members is a piezoelectric actuator for changing a distance between the portions when being driven, whereby to adjust a thread holding force.

Abstract: An upper feed device for a sewing machine comprises an upper feed arm having its base end coupled with a longitudinally swinging crank and an upper feed dog attached at its front end. The mechanism for vertically moving the upper feed arm consists of a clutch mechanism comprising a lever rotatably mounted on a vertical feed shaft and swinging in cooperation with the main shaft, an abutment disposed on the lever and an abutment of a collar disposed on the vertical feed shaft, which is capable of disconnecting the cooperation of the lever and the vertical feed shaft, and a crank having a roller slidably fitting with a guide disposed parallel to the upper feed arm and which moves vertically through its attachment to the vertical feed shaft. A block is provided below the roller to engage with the free lower end surface of the crank and is adjustable in its mounting position to prevent the roller from descending more than specified.

Abstract: A sewing apparatus for forming cuffs for sweat jackets or anklets for sweat pants or the like. The apparatus includes a movable table carrying an end of an elastic tape continuous to a supply source. The tape advances on a carrying table to a cutting device where the tape is cut. The front end of the tape is transferred to gripping blades which can be inverted, simultaneously with the return movement of the movable table. The tape is further let out toward the gripping blades by a predetermined length feeding device and the gripping blades turn so that the tape front end is folded back on the tape rear part. The tape rear part is cut off and the folded cut-piece is supplied to a sewing machine by a conveying device automatically and sewn to join both ends along the cut line.

Abstract: In a thread supply device used in a sewing apparatus having a plurality of needles and a looper mechanism, needle threads guided to the needles and a looper thread guided to the looper are cut by a thread cutting unit at a cutting position, which is off a thread supply path, after a sewing operation is finished but before the following sewing operation starts. The thread supply device comprises a supply mechanism, a stopping mechanism, a memory and a control unit. The supply mechanism forcibly supplies the needle threads and the looper thread. The stopping mechanism stops the threads from being supplied. The memory stores an extra length of each thread, which is required for a cutting operation. The control unit reads out the extra length from the memory and controls the supply mechanism and the stopping mechanism so that each thread is supplied in the extra length.

Abstract: An automatic thread supply device for a conventional overlocking sewing machine is disclosed. Each of a needle thread, an upper looper thread and a lower looper thread is supplied to a thread supply roller but the supply is stopped for an optimum period by a thread holder, whereby the supply length of each thread is adjusted. In forming a thread chain, the total supply length of the looper threads is not more than five times of the length of the needle thread, and the smallest length of the above threads is not more than half of the total length of the remaining threads. In this way, a highly expandable thread chain is formed having a good appearance.

Abstract: A waist part cloth guiding device for a sewing machine comprises a guide which folds and guides a side edge portion of a cylindrical cloth to enclose a ring band ahead of the needle drop point, while feeding the band together with the cloth in a cloth feed direction by a forced feeding device, regardless of the operation of a main shaft of the sewing machine. After setting the ring band to be inserted into the folded portion of the cylindrical cloth at a position close to the needle drop point of the sewing machine, the side edge portion of the cylindrical cloth may be automatically guided and folded to the lower side of the ring band.

Abstract: A cover thread cutter for a multi-needle sewing machine, the hook of the thread cutter retracts at an oblique angle above a curved cover thread laying finger and captures the cover thread at a position above the curved cover thread laying finger. While pulling the captured cover thread up to the cutting position, it is held against a specified needle, as in ordinary seam forming, and the thread end is held in this state after being cut off.

Abstract: A taped chaining thread sewing device is designed to sew by operation of an overedge sewing machine a tape into the upper surface of the fabric sent into the needle location of the sewing machine, and also sew the chaining thread cut off from the preceding fabric into the lower surface of the fabric. The tape is cut off together with the unnecessary edge portion of the fabric by a cutter at the start of sewing of the leading end from the sewing part on the fabric. Before the final end of the fabric passes the cutter, a tape guide of the taped chaining thread sewing device moves, and therefore the unsewn portion of the tape is cut off together with the unnecessary edge portion of the fabric from the sewn part by the cutter. By the chaining thread sewn into the beginning part of sewing of the fabric, it is not necessary to perform any particular bar tacking job at the beginning of sewing in a separate process.

Abstract: A chaining thread sew-in device for sewing a chaining thread produced consecutively in the seams of a preceding cloth and in the seams of a next cloth when forming seams by an overlock sewing machine. The free end of the chaining thread (Ch) cut off from the preceding cloth is inserted into an insertion hole (H) opening on a sewing machine working face (1a), and the inserted chaining thread (Ch) is pinched beneath the sewing machine working face (1a), so that the chaining thread to be sewn into the seams of the next cloth is set at specified position on the sewing machine working face (1a). The chaining thread set at a specified position is moved to a cutter (40) installed side of the machine by driving a sub-pinching plate (72, 272), and is cut off from the pinched part by this cutter (40).

Abstract: A sewing method and apparatus is disclosed for preventing raveling of a cut cloth edge in the making of garments such as slacks and skirts. A pair of sewing machines symmetrically arranged with respect to a cloth feeding line are disposed oppositely to each other. Each sewing machine has an auxiliary guide for contacting the upper surface of a cloth, a cloth edge guide and a cloth stopper. Opposite edges of the cloth are simultaneously and automatically guided along respective sewing lines by the guides and serged by the sewing machines without failure. In operating the pair of sewing machines, another additional sewing machine can be operated to serge other edges of the next cloth.

Abstract: A chaining thread sew-in device for sewing a chaining thread produced consectively in the seams of a preceding cloth and in the seams of a next cloth when forming seams by an overlock sewing machine. The free end of the chaining thread (Ch) cut off from the preceding cloth is inserted into an insertion hole (H) opened on a sewing machine working face (1a), and the inserted chaining thread (Ch) is pinched beneath the sewing machine working face (1a), so that the chaining thread to be sewn into the seams of the next cloth is set at specified position on the sewing machine working face (1a). The chaining thread set at a specified position is moved to a cutter (40) installed side of the machine by driving a sub-pinching plate (72, 272), and is cut off from the pinched part by this cutter (40).

Abstract: A needle thread feed regulating device utilized in high speed overedge sewing machines which form safety stitches composed of overedge stitches and double chain stiches. The needle thread feed regulating device comprises a thread guide mounted on the sewing machine frame and an oscillating thread guide which moves in cooperation with the sewing machine main shaft. The oscillating thread guide has a cam plate which regulates the feed of both the thread for overedge stitches and the thread for double chain stitches.

Abstract: An automatic thread supply device for a conventional overlocking sewing machine is disclosed. Each of a needle thread, an upper looper thread and a lower looper thread is supplied to a thread supply roller but the supply is stopped for an optimum period by a thread holder, whereby the supply length of each thread is adjusted. In forming a thread chain, the total supply length of the looper threads is not more than five times of the length of the needle thread, and the smallest length of the above threads is not ore than half of the total length of the remaining threads. In this way, a highly expandable thread chain is formed having a good appearance.

Abstract: In the needle thread wiper of sewing machine according to the invention, the hook formed at the front end of a leaf spring is projected in or out from the front end of the guide element formed nearly in a J-form, and when inserting this hook into the front end of the guide element, the needle threads extending between the needle and cloth is hooked on the front end of this hook so as to be placed into the front end of the guide element together with the hook. At the front end of the guide element, at the positions corresponding to the both flat surfaces of the leaf spring, notches are formed so as to extend from the front end to the base part side. The needle thread introduced into the front end of the guide element is guided by the notches and placed deeply into the guide element. The needle thread is held merely in a state of being hooked between the hook and the guide element, and so that is easily unhooked, almost without any resistance, when the needle is lowered upon start of next sewing step.

Abstract: A clamping mechanism installed on a circulating conveyor is composed of a clamp and a supporting plate and a latch lever axially attached to the supporting plate. The clamp is designed to be opened to a specified extent by a coiled spring. When the clamp is closed against the operation of the coiled spring, it engages with a latch of a latch lever so as to be locked.A cloth sent out from the sewing machine advances between the opened clamp and the supporting plate. The clamp is closed by an air cylinder and clamps the cloth.When the latch lever engages with a limiting lever set at a specified position in the direction of movement of the conveyor, the lock is unlocked, and the clamp is opened to release the cloth.

Abstract: A chaining thread sew-in device of an overlock sewing machine is related having a first pinching plate and a second pinching plate which form a part of the working face of the sewing machine on the operator side of a needle drop point. The plates are capable of opening an insertion hole into which a free end side of a chaining thread linked to the sewing machine side can be inserted in the working face by driving the first pinching plate, capable of pinching the chaining thread between itself and the second pinching plate, toward the second pinching plate. By returning the first pinching plate to the initial position while the chaining thread is inserted into the insertion hole a cutter 30 capable of crossing the chaining thread cuts the chaining thread by moving the second pinching plate 71 to the first pinching plate 71 side in when the chaining thread is inserted into the insertion hole.

Abstract: A thread regulating apparatus for a sewing machine having a plurality of thread regulators. Each regulator nips a thread between a pair of tension discs to apply tension to the thread. The tension applied to the thread is determined according to combination patterns of tension values stored in a memory.

Abstract: A thread cutter for an interlock sewing machine wherein the sewing machine has a small diameter cylindrical arm and the cloth being sewn is fed along the axis of the arm. A plurality of needles are disposed along a line orthogonal to the axis of the arm and an arcuated, movable member having a hook at its tip is pivotably supported ahead of feed dogs on the sewing machine relative to the line of feed. The arcuated, movable member is turned by means of an operative plate disposed along the axis of the arm and, in cooperation with a fixed blade, cuts threads after the cloth has been sewn.

Abstract: A needle driving apparatus for a sewing machine for allowing oscillatory movement of a needle bar through the motion of a lever which oscillates up and down interlocking with a main shaft, wherein a rectangular slider is rotatably supported by a fork provided on the end of the oscillating lever. On the upper end of the needle bar is fixed a guide member having a guide groove which is orthogonal with the needle bar and slidably fitted to the fork of the oscillating lever, and the rectangular slider is fitted in the guide groove of the guide member.

Abstract: A thread cutting device for a cylinder bed sewing machine for sewing by means of a plurality of needles a piece of fabric supported on a cylindrical bed while transporting the fabric piece in a given direction, wherein a hook portion of a thread catch member which is adapted to plunge into and retreat from needle thread loops in orthogonal relation to an obliquely inclined plane of opening of the needle thread loops so that a plurality of needle and looper threads are accurately caught into the hook portion and then carried along thereby for cutting. In addition, an arrangement is disclosed which enables the mounting of the thread cutting device without interferring with the movement of a looper, even if the available space within the bed is very limited.