Abstract: A sewing machine includes a thread take-up lever that supplies an upper thread to a needle from a thread supply source, a hook which catches the upper thread inserted in the needle, and which intertwine the upper thread with a lower thread, and a control unit that controlling a hook release phase at which the hook releases the upper thread in such a way that a hook/upper-thread necessary amount that is necessary when the upper thread is intertwined with the lower thread becomes smaller than a thread-take-up-lever/upper-thread supply amount that is supplied by an operation of the thread take-up lever. The control unit controls the hook release phase at a plurality of timings.

Abstract: To provide a sewing machine that can control tension on a needle thread and tension on a bobbin thread on a per-stitch basis; that enables even heads of a multi-head embroidery sewing machine to form an identical embroidery; and that enables even a plurality of sewing machines to form identical embroidery. A memory device stores for each stitch of embroidery data a needle thread control torque value and a bobbin thread control torque value. In a needle thread torque control zone, an upstream grip section main body is closed, and a downstream grip section main body is opened. A needle thread motor is subjected to torque control in accordance with the needle thread control torque value. In the meantime, in a position control zone, the upstream grip section body is opened, and the downstream grip section body is closed, thereby subjecting the needle thread motor to position control.

Abstract: A sewing machine includes a thread holding device disposed downstream of a thread take-up lever and upstream of a needle bar in terms of a threading path of a needle thread, and including a fixed first disc and a movable second disc movable by an electromechanical unit between holding and releasing positions to be closer to and remote from the first disc, respectively. The first and second discs respectively have first and second holding surfaces cooperatively defining a thread holding clearance to permit passage of the needle thread therethrough. The needle thread can be clamped in the thread holding clearance so as to prevent the needle thread being pulled out of the needle during a thread cutting procedure. A required amount of the needle thread remaining on the needle can be secured.

Abstract: A thread tensioning device or apparatus for a sewing machine enables accurate, repeatable measurement and monitoring of the compression forces applied to the thread tensioning discs thereof. The apparatus further includes a visual display or output corresponding to the actual amount of compressive force being applied. The device further includes a comparator, which compares the electrical signal to a predetermined reference value to control or regulate the normal operation of the sewing machine.

Abstract: A thread feeding apparatus for a sewing machine which has a simplified mechanism for accuracy of manufacturing and improved durability so as to accommodate high speed sewing. The thread feeding apparatus for the sewing machine has upstream grippers for respectively gripping an upper looper thread and a lower looper thread, closed by a stitch forming device at the time of the stitch forming and opened at the time of the cloth feeding, downstream grippers for gripping the respective threads introduced from the respective upstream grippers, opened at the time of the stitch forming so that the respective threads are pulled by the stitch forming device and closed at the time of cloth feeding, and reciprocators which are respectively driven in a synchronous manner with a left needle, a right needle, an upper looper and a lower looper, at the time of cloth feeding.

Abstract: A sewing machine that has at least one needle which moves with alternating motion, taking the upper thread through the piece to the sewn, a shuttle to hook an upper thread to form a loop below the piece to be sewn, a bobbin housing in a bobbin-case located internally in the shuttle, the bobbin containing a lower thread which overlaps the upper thread through the loop, two mutually independent levers which act on the upper thread and are mobile with periodic motion between a position where the upper thread is allowed to be fed to the shuttle and a position of complete recovery of the upper thread in which the loop is closed to form a stitch, the upper thread being synchronized with movement of the levers by periodic tension.

Abstract: A thread feeding apparatus for a sewing machine which has a simplified mechanism for accuracy of manufacturing and improved durability so as to accommodate high speed sewing. The thread feeding apparatus for the sewing machine has upstream grippers for respectively gripping an upper looper thread and a lower looper thread, closed by a stitch forming device at the time of the stitch forming and opened at the time of the cloth feeding, downstream grippers for gripping the respective threads introduced from the respective upstream grippers, opened at the time of the stitch forming so that the respective threads are pulled by the stitch forming device and closed at the time of cloth feeding, and reciprocators which are respectively driven in a synchronous manner with a left needle, a right needle, an upper looper and a lower looper, at the time of cloth feeding.

Abstract: A thread tension device for a sewing machine includes two or more pairs of discs for engaging with two or more threads. Two or more tension applying members are engaged with the pairs of discs for applying a biasing force against the pairs of discs. Two or more micro-adjusting mechanisms are engaged with the tension applying embers for adjusting the biasing force against the pairs of discs. An actuator is engaged with the micro-adjusting mechanisms for actuating the micro-adjusting mechanisms simultaneously.

Abstract: A apparatus for forming a knot where a knot is formed in chain-stitching. In the method, a first loop is formed by a stitch to an article to be sewn, two stitches ahead of a final stitch, is drawn through a second loop which is formed by a stitch one stitch ahead of the final stitch, whereby a knot where the first loop is fastened by the second loop is formed, such that a third loop is inserted through the second loop and is then cut. The sewing machine including a single needle and a rotary looper and including a yarn feed adjusting device for adjusting a degree of feed of a yarn to the single needle. The yarn feed adjusting device sets a fed volume of the yarn during formation of the second loop to a value larger than that of the final or third loop and the first loop.

Abstract: An apparatus for clamping an individual thread out of a plurality of threads, which are guided in side-by-side relationship, includes a transport unit with a drivable transport shaft and a rotatable contact pressure shaft. A thread is guided between the shafts. A clamping unit with an abutment and a clamping pin acting thereagainst is used for clamping a respective thread. Between the clamping pin and one of the functional parts of the transport unit, there is an operative connection. Increasing the clamping of a thread in the clamping unit causes an increasing release of the thread in the transport unit and vice-versa. The operative connection can adopt a central position in which the thread is loose both in the transport unit and in the clamping unit.

Abstract: An overlock sewing machine which can switch its operation from an ordinary over-edge chain stitch to a rolled seam or vice versa with no requirement for a complicated operation of adjusting thread tension is obtained. This overlock sewing machine is provided with a spring for providing a thread with prescribed tension. The overlock sewing machine is further provided with a switching mechanism for switching the thread tension between that for the rolled seam and that for the over-edge chain stitch by switching the spring between a tensioning state and a non-tensioning state. Thus, the thread tension is readily switched between that for the rolled seam and that for the over-edge chain stitch.

Abstract: A sewing machine includes a stitch forming device which forms stitches on a work sheet by locking an upper and a lower thread with each other, and a tension changing device which changes a tension of the lower thread to stop supplying of the lower thread to the stitch forming device at a predetermined timing. A sewing machine for forming stitches on a work sheet by locking an upper and a lower thread with each other, includes a pattern selecting device which selects one of a plurality of different stitch patterns, a detecting device which detects the selected one stitch pattern, and a tension changing device which changes, based on the detected one stitch pattern, a maximum tension of the lower thread to a corresponding one of a plurality of different tension values.

Abstract: A thread feeding device for a sewing machine, is simply constructed but can feed a plurality of looper threads individually in amounts necessary for each seam with adjustment of the tensions of the looper threads by one adjustment knob. The thread feeding device includes a shaft fixed on the machine body orthogonally of the feeding direction of a plurality of threads. A rotor is mounted on the shaft as to rotate intermittently in one direction only. A plurality of thread holders are provided on the rotor for holding and letting off the threads individually. In each thread holder the radius from the center of rotation of the rotor to the position where the thread is held is set to a value corresponding to the individual length of feed of the thread.

Abstract: A multi-needle chain-stitch seam is secured against unravelling and loosening by the following steps: A beginning region (A) of the seam is formed with short needle thread loops (6,7) an intermediate region (B) of the seam is formed with long needle thread loops (9) and an end region (C) is again formed with short needle thread loops (6,7).An adjusting member (67) actuated in a controlled manner on a sewing unit influences the formation of the stitches of the seam.

Abstract: A thread tensioning device comprising a stationary electromagnet mounted on a sewing machine arm and a tensioning wheel having a relatively low mass. The tensioning wheel is rotatable concentric to a longitudinal axis of the electromagnet and is mounted on the electromagnet so as to be moveable only slightly in the direction of the longitudinal axis. A friction disk is positioned at one end of the electromagnet so as to be between the electromagnet and the tensioning wheel. A current flows through an excitation winding in the electromagnet and its value is varied within given limits by a suitable current control device, thereby causing the electromagnet to pull a flat side of the tensioning wheel with corresponding force against an application side of the friction disk, whereby a corresponding variable thread tensioning force is applied to a sewing thread passing through the tensioning wheel to the sewing machine.

Abstract: A thread-pulling device is fastened on the arm of a sewing machine. The thread-pulling device has a thread clamp that can be opened and closed on the thread, and can be moved toward and away from the sewing machine arm. In operation, the needle thread, which has been pulled off the spool and extends to the sewing needle, is conducted through the thread clamp. After an initial seam has been completed, the thread clamp is closed on the thread and moved to an extended position which is remote from the arm. In this way, a given length of the needle thread is pulled off the spool, thus providing the proper length of needle thread for dependable formation of the first stitch of the following seam. Then, shortly after the start of the following sewing process, the thread clamp is moved back over an intermediate distance toward the sewing machine arm so as to pull back the initial piece of the needle thread that is now hanging down from the back of the material at the start of the seam.

Abstract: An apparatus and a method for supplying thread in a chain stitch sewing machine are disclosed, the apparatus comprising a needle vertically reciprocating between a top end point and a bottom end point in one sewing cycle; a looper horizontally reciprocating in one sewing cycle; a thread supply device for forcibly supplying a needle thread to the needle; and a thread supply control device for controlling the thread supply device so that the needle thread is supplied in at least two periods in each sewing cycle, the periods being discontinuous.

Abstract: An apparatus and method for maintaining the continuity of a free thread chain between successively sewn fabric parts by tensioning the free thread chain with a puller roller activated by drive means responsive to the sensing of the edges of the fabric parts.

Abstract: A sewing apparatus displays a stitch pattern and forcibly supplies a thread based on the displayed stitch pattern. The apparatus comprises a sewing mechanism, an automatic thread supply device, a key input unit, a memory, a selector and a display. The sewing mechanism has a sewing section which includes a needle and a looper driven in accordance with a rotation of a main shaft. The automatic thread supply device forcibly carries a needle thread and a looper thread to the sewing section. The key input unit sets lengths per stitch of the needle thread and the looper thread which are to be supplied by the automatic thread supply device to the sewing section. The memory stores a plurality of stitch patterns in correspondence with combinations of the lengths of the threads to be supplied per stitch. The selector selects one of the stitch patterns corresponding to the combination set by the key input unit. The display displays in graphics the stitch pattern selected by the selector.

Abstract: A yarn brake which can be used in projectile looms and rapier looms is actuated by a stepping motor with the rotational movement of a drive shaft of the stepping motor being converted to a linear movement of the braking member of the yarn brake.

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 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: The feed dog (17) for the fabric in a sewing machine is provided with a spring-wire (21) bent and passing through a hole of a support (23). When the feed dog (17) is in its upper position, the support (23) abuts the plate (18), which lowers the end (24) of the wire (21) so as to exert a tension on the lower thread (8) of the seam. When the feed dog is lowered, the wire (21) resumes its normal position, namely its end (24) is displaced upwardly with respect to the dog (17) and the thread (8) is thus relaxed.

Abstract: A device is provided for controlling the tension of a longitudinally moving thread. The device includes at least two adjacent plates which are applied one against the other and between which the thread passes. The plates, and thus the thread, can be tightened so that the desired tension can be creatred. Opposed surfaces of the plate each incorporate at least one gripping surface for the thread which cooperates with at least one corresponding gripping surface of the other plate. The periphery essentially about the surfaces is formed with at least two indentations arranged in such a way that each indentation of the gripping surface of a plate coincides with at least a portion of a corresponding indentation on the gripping surface of the other plate.

Abstract: An upper thread carried by a vertically reciprocating needle is drawn from a bobbin through a tensioning device, a supply device and a take-up lever. A predetermined amount of the upper thread is first supplied by actuating the supply device, while applying no tension thereto. An additional amount of the upper thread is then supplied by operation of the take-up lever with a predetermined tension being given thereto. The additional amount is detected by a sensor. The supply device includes a one-way clutch for allowing the upper thread to travel in a predetermined direction which, however, may not be conveyed from the needle side when the supply device is made operative. A CPU controls the amount of thread first supplied by the supply device which will always be smaller than an amount actually required for producing a stitch, resulting in an additional amount to be supplied supplemental in cooperation with the tensioning device.

Abstract: A thread securing device in a sewing machine wherein an upper thread located along a thread guiding path is caught during the travel of a thread take-up member to effect automatic hooking of the thread thereto. The thread securing device includes a thread saving member capable of saving an amount of the upper thread corresponding to a predetermined amount of the upper thread to be taken up by the thread take-up member during its movement from a thread loosening position to a thread take-up position, and capable of feeding the saved amount of the upper thread freely in accordance with the thread take-up movement of the thread take-up member; and an actuating member adapted to catch the upper thread extending along the thread guiding path when the thread take-up member is not holding the upper thread and then supply an amount of the upper thread corresponding to the predetermined amount, to the thread saving member.

Abstract: A thread brake for braking a weft thread in a weaving machine includes a rigid stop and an elastically deformable blade which has a free end supported to press resiliently against the rigid stop. Thread guides are provided to guide weft threads between the rigid stop and the elastically deformable blade. The thread brake is activated when the deformable blade elastically presses against the rigid stop. When contacted by a switching device, however, the elastically deformable blade is pushed against its resilient force and removed from the rigid stop, at least in the region of the switching device, deactivating the thread brake.

Abstract: A sewing apparatus for use on a quilting machine having an intermittent tension mechanism and a hopping presser foot mechanism cooperating with eccentric cams located on the main drive shaft of the sewing apparatus.The intermittent tension mechanism includes an eccentric cam having an outer surface adapted to abut a cam follower which engages thread holding tension disks that are biased together by action of a spring. Pressure between the disks is increased during the final tightening of the stitch due to the reciprocating motion of the cam follower.The hopping presser foot mechanism includes a rocking bar pivotally connected at one end to a reciprocating arm and slidingly and pivotally connected at the other end to a presser foot bar. A ball and race mechanism pivotally connects the rocking bar with the reciprocating arm. The arm reciprocates due to action of the eccentric cam.

Abstract: A method of automatically controlling thread tension in a sewing machine according to which a first thread tension device is provided between an upper thread source and a thread take-up lever, and a second thread tension device is provided between the first tension device and the thread take-up lever. The first thread tension device is operated to apply a constant pressure to the upper thread such that the thread take-up lever is able to draw out the upper thread upon moving upward. The second thread tension device is operated to fixedly hold the upper thread until the thread take-up lever moves upward to an upper dead point thereof through a lower dead point thereof, at which the take-up lever moves downward to supply the upper thread to the needle. The second thread tension device is further operated to effect release of the upper thread when the thread take-up lever reaches the upper dead point thereof and until the thread take-up lever moves downward to a thread supply starting position thereof.

Abstract: An automatic thread tension control sewing machine comprising thread tension controller for clamping an upper thread with a predetermined pressure to control an amount of the upper thread supplied to a needle and a loop taker, thread tension setting means that determines a pressure with which the thread tension controller clamps the upper thread, upper thread supplying mechanism, a releasing mechanism controlling operation of the upper thread supplying mechanism, and a central processing unit for actuating the releasing mechanism in accordance with a selected stitch pattern.

Abstract: A sewing machine includes an automatic thread tension adjusting device comprising an upper thread tension member arranged in an a thread running path between an upper thread source and a main thread take-up lever. An auxiliary thread take-up lever is arranged in the upper thread running path between the main thread take-up lever and a needle holding the upper thread. A thread engaging part guides the upper thread. A thread presser is arranged laterally of the upper thread running path between the main and auxiliary thread take-up levers and normally clamps the upper thread. A detector detects a predetermined rotation phase of a drive shaft of the machine and thread elongation, respectively, and generates respective electric signals. A control circuit causes the thread presser to release the upper thread in response to the electric signals generated by the detector.

Abstract: A sewing machine having a vertically reciprocating needle carrying an upper thread, a needle plate secured to a sewing machine housing and provided with a needle penetrating hole, a loop-taker arranged below the needle plate and operated in synchronism with reciprocation of the needle for interlocking a lower thread carried thereby with the upper thread, and a feed dog for feeding a fabric placed on the needle plate in a predetermined direction on which a stitch composed of the interlocked upper and lower threads has been formed. A swingable arm is operated to interfere with the normal travelling path of the lower thread between the loop-taker and the needle hole to draw a predetermined amount of the lower thread out of the loop-taker, while the fabric is not being fed.

Abstract: A lower thread tension adjusting device for a sewing machine comprising first and second tension arrangements mounted on a bobbin carrier of the sewing machine for tensioning a lower thread with a predetermined tension and a predetermined additional tension, respectively. A positioning device is mounted on the bobbin carrier and movable between first and second set positions in which the positioning devices moves the second tension arrangement to operative and inoperative positions wherein the second arrangement provides and does not provide the predetermined additional tension of the lower thread. A guide assembly guides the lower thread to positions adjacent to one end and a center of a laterally elongated needle hole and simultaneously guides the positioning device to the first and second positions thereof. A control unit moves the guide assembly between first and second guide positions thereof in accordance with selected patterns of straight and zigzag stitches, respectively.

Abstract: In a sewing machine provided with a thread supply stopping device for selectively controlling supply of a needle thread between a needle thread supply source and a take-up lever, an adjustable pre-tension exerting device exerts a tension equal to or lower than a tension of a bobbin thread on the needle thread between the needle thread supply source and the thread stopping device.

Abstract: A thread undercut attachment for use on multi-needle sewing machines uses a single piston actuated cutting blade which passes through the sewing area beneath the workpiece and above the loopers. To prevent the needles and loopers from becoming unthreaded or to prevent undue lengths of thread after cutting, apparatus is provided for creating a measured amount of slack in the threads leading to the needles and loopers, and then holding the threads firmly to prevent further payout of thread when the workpiece is pulled toward the operator.

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 needle thread tension control system includes a pair of thread clamping members and a driving mechanism for driving the thread clamping members in timed relation with the rotating speed of a arm shaft. A controlling mechanism controls the driving mechanism to effect a disengaging displacement of the thread clamping members to be smaller than an amount of engaging displacement therof for a predetermined angle of rotation of the arm shaft. The controlling mechanism includes a specific cam drive linkage in the driving mechanism to effect the differential displacements of the clamping members.

Abstract: A sewing machine comprises a bed 3 on which a work-supporting table 3a is defined and from which a post 4 carrying a cantilevered support arm 5 provided with a needle-holding head 6 at its free end, rises up. An upper shaft 9 performing a rotating motion is housed within the arm 5 and it imparts a reciprocating movement, through a connecting rod-crank linkage 10, to a needle bar 11 vertically slidable in the head 6. Along the upper shaft 9 a plurality of eccentrics 19, 20, 21 are distributed to which auxiliary sewing operation devices 22, 32, 39 detachably associated with the sewing machine 1 are operativley engageable through respective connecting rods 23, 33, 50 and transferring motion mechanisms. A preformed opening 5 is formed in the support arm 5, through which connecting rod 50 is mounted to eccentric 21. An opening 36 is formed in support arm 5 through which stem 37 passes.

Abstract: An apparatus for stitching material in a sewing machine having a throat plate having a stitch tongue, a stitch forming instrumentality for forming an overedge stitch having a needle, an upper looper, and a lower looper. The apparatus has first plates for applying tension to a first thread passing to the upper looper, second plates for applying tension to a second thread passing to the needle, third plates for applying tension to a third thread passing to the lower looper, fourth plates for selectively applying tension to the first thread, fifth plates for selectively applying tension to the second thread, and sixth plates for selectively applying tension to the third thread.

Abstract: A method and apparatus for forming stitches with a sewing machine by periodically rewinding needle thread onto its spool as a sewing needle pulls off bobbin thread so as to form tight lock stitches without a take up lever.

Abstract: A servo device for a multineedle sewing machine which includes two needle bars; driving and steop devices for said needle bars; devices for engaging and disengaging the two needle bars relative to the driving and stop devices; a feed-length adjustment device associated with at least one feed dog for the transport of the material being sewn; an adjustable thread tensioning device for the needle threads; devices for locking each needle bar selectively in its highest position; a positioning drive for the multineedle sewing machine; and a device including a position indicator attached to an arm shaft of the multineedle sewing machine, for adjusting the speed of rotation and positioning of the needle bars in predetermined positions.

Abstract: A garment has a collar/lapel which is produced by folding a part of the boundary area between a body piece and a flyback. A first expansible and contractible interfacing member is fitted to an area of the body which becomes the rear side of the collar/lapel when it is folded but no interfacing is fitted to the area of the flyback which becomes the front side of the collar/lapel when it is folded. A second expansible and contractible interfacing member is fitted to the area of the flyback which becomes a rear side of the collar when it is folded. A stitch by means of which the first expansible and contractible member is sewn to the body is provided in the proximity of the position where the first expansible and contractible interfacing member fitted to the body is folded as a collar.

Abstract: In a conventional sewing machine, as the take-up lever is driven by the take-up lever crank, the take-up lever does not keep its uppermost position during the feed motion of a work fabric. Accordingly, the length of the thread path extending from the thread supply source to the eye of the needle varies remarkably during feed motion, and thus the needle thread equivalent to the amount consumed by stitch feed motion cannot be extracted from the supply source. In the present automatic needle thread supply control system, during a specific period from a time before finishing of each feed motion to a time when the needle reaches the throat plate, the take-up lever is held at its uppermost position. During a given period corresponding to the comparatively latter half of the specified period, thread supply stopping is released, whereby the needle thread equivalent to the amount consumed by each stitch feed motion can be extracted certainly from the supply source toward the take-up lever.

Abstract: When a lower thread is effected with tension by an upper thread, a lower thread tension device is actuated in a certain working distance with very small resistance to an extent that a lower thread is drawn as if without resistance. If the lower thread is effected with said tension outside of said distance, it is not drawn out with large resistance. An actuation means successively receives information about thread consumed in each of the stitches and information about rotation phase of the sewing machine from a phase sensor. In the distance of a strong resistance, the lower thread is prohibited from drawing, and the thread is tightened in this distance.

Abstract: There is a zigzag sewing machine provided with a horizontal rotary loop taker device which is restrained with respect to the rotation direction, and holds therein a bobbin carrier horizontally attached, and is supplied with a lower threads from the left side to the left basic line marked with an axial line in front of the needle, and provided with a feed dog which is provided nearly to passage of the needle to move vertically and laterally. In such a sewing machine a cam portion is provided for supplying the lower thread to a lower thread contacting portion of the bobbin carrier or a lower thread contacting portion of a part connecting right and left teeth of the feed dog, whereby the amount of supplying the lower thread is adjusted properly with respect to the left basic line and the right basic line during zigzag stitching, and the slack amount of the lower thread is adjusted properly with respect to the left basic line and the right basic line during forming stitches.

Abstract: A device at a sewing machine for applying a tensile stress in a material to be fed for sewing, particularly a thread, a ribbon etc. Several pneumatic cylinders are arranged in parallel for generating a variable force acting upon at least one friction element. Several pneumatic cylinders are combined into groups, which are selectively controllable by compressed air valves and a selector switch. Due to the special construction of the pneumatic cylinders, there is obtained a cost-saving tensioning device for generating a tensile stress in a material.

Abstract: A method for drawing the free end of the needle thread from the upper workpiece surface to the lower workpiece surface when sewing the first stitch of a seam to be produced by a sewing machine having a reciprocable needle, which carries the needle thread drawn from a spool by means of a thread lever, at least one presser foot lowerable upon and liftable from the workpiece, and a rotatingly drivable hook, the point of which seizes and withdraws the needle thread for the stitch formation. In order to safely and automatically prevent the thread end of the needle thread from being clamped between the presser foot and the workpiece, the needle thread is held between the needle and the thread take-up lever while the needle thread loop is withdrawn by the hook beak, so that the thread end is drawn through the workpiece by the hook beak.

Abstract: The invention relates to a method of controlling an upper thread in a sewing machine. The sewing machine includes a needle holding the upper thread and vertically movable in association with a spindle, a loop taker holding a bobbin case carrier having a lower thread and rotatable in association with the spindle for forming a lock stitch in cooperation with the needle, and a thread take-up lever vertically movable in association with the spindle for loosening or taking up the upper thread. For a period of time from a moment at which a loop of the upper thread is released from a loop taker to a moment at which stitch tightening is completed, a tension required for stitch tightening is rendered to the upper thread.

Abstract: Opposing plates of a thread tensioning device for use on a lock stitch sewing machine in a thread handling system wherein needle thread is caused to pass between elongate members of a thread holder which meters thread to the looptaker of the machine are formed with recesses through which the thread can fall without restraint to supply thread to the looptaker during the movement thereof from a loop seizing to a cast-off position.

Abstract: A device is disclosed for pulling out and cutting off the needle and looper threads in a sewing machine with a delivery roller for delivering material to the machine sewing station. The delivery roller is driven over a first drive, which is dependent on the sewing machine main drive and over a second drive, which is independent of the sewing machine main drive. On the looper of the sewing machine is secured a cutting blade for the needle thread. Furthermore, a needle thread clamp is provided. In order to manage, with a single means for pulling out the needle and looper threads by different lengths, a cutting device for the looper thread is arranged between the cutting blade and the delivery roller, with a guide which is traversed by a thread inlet groove and with a counterknife for a thread severing knife that moves transverse to the material feeding direction. The delivery roller is driven over the second drive for pulling out the threads.