Abstract: A device for disabling and enabling one or more needles in a quilting machine, a multi-needle embroidery machine, or the like, is described.The device comprises a linear actuator (24) adapted to carry a needle (22) and to keep the latter, for a predetermined time, in a raised position relative to fabric (10) to be sewn.The device includes stitching yarn (44) return means (38) being actuated when needle (22) is disabled, in order to subject to a limited tension the portion of stitching yarn located between the disabled needle and the fabric to be sewn, to prevent the yarn from becoming tangled and from breaking.Furthermore, during the entire operating stage as mentioned above, the known yarn tensioning device (48) through which the stitching yarn is led before arriving at the needle, is disabled.

Abstract: A relatively long needle (22) is supported at the lower end of a needle bar (28). The needle bar (28) and needle (22) are moved up and down and forwardly and rearwardly. The needle bar (28) and needle (22) are moved forwardly while they are in materials (M) which are being sewed together, to in that manner advance the materials (M) stitch by stitch. The materials (M) are supported on a bed (10) which includes a slot (20) which is elongated in the direction of the stitch path. The needle (22) is received in the slot (22). A side boundary of the slot (20) provides a side guide surface (84) which is contiguous a first side of the needle (22). An upper thread (76) extends downwardly from a thread guide (110) into a side groove (86) in the first side of the needle (22), to and through a needle eye (80). A recess (82) is formed in the second side of the needle (22) above the needle eye (80). Following downward movement of the needle (22) through the materials (M), the needle (22) is moved upwardly.

Abstract: A sewing machine comprises a thread deflecting device arranged between a thread take-up lever and a needle and which in response to a swinging movement of a needle bar effected in response to selection of a zigzag stitch, deflects the upper thread laterally of a fabric feeding direction. A thread blocking device is provided on one side of the thread deflecting device. The sewing machine further comprises an actuator operated in response to actuation of a zigzag stitch pattern selecting key to move the thread blocking device to an operative position thereof. The thread blocking device in the operative position blocks the upper thread as it is deflected in one direction by the thread deflecting device to give a predetermined degree of tension to the upper thread, so that the stitch is tightened on one side of the zigzag stitch in addition to the tightening of the stitch by a thread take-up lever.

Abstract: A cam shaft of a rotary looper thread take-up is extended short of a thread guide and thus provides a free space there-between. A thread introduced from the tip-end-side of the cam shaft is prevented from being entangled into the cam shaft when the looper thread becomes broken. In a preferred embodiment, three slit-like guides placed in parallel and two cams placed there-between are effective to introduce the looper thread into the rotary looper thread take-up by a simple operation without requiring an operator to visually align the thread to pass through an eyelet.

Abstract: A thread guiding device in a sewing machine comprising a guide path for guiding an upper thread from a thread source to a needle and defined by a first thread guide, a pair of discs for releasably holding an upper thread, and a second thread guide formed by a spring hook of a thread tension spring member and an end portion of a take-up lever, the first and second thread guide and the thread tension spring member lying in a common plane to define a straight-line guide path.

Abstract: A sewing machine having an upper thread supply, a main thread take-up lever and a needle, is provided with an automatic upper thread tension device for absorbing slackening of the upper thread during its supplying phase. The tension device includes a thread tension member arranged between the upper thread supply and the main thread take up lever to impart an adjustable pretension to the upper thread. A thread presser is arranged laterally of the path of the upper thread between the main thread take-up lever and the needle to guide the upper thread from the thread tension member to the main thread take-up lever and to clamp the upper thread and release the same during the predetermined supplying phase. An auxiliary thread take-up lever is arranged between the main take-up lever and the needle and cooperating with a thread guide to draw the slackened part of the upper thread against the guide during the supplying phase.

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: Apparatus and method for severing the needle and looper threads of a chain stitch formed by a sewing machine having an in-line looper system. The sewing machine has a needle plate and a needle carrying the needle thread through the material and the needle plate to form a needle loop of needle thread therebelow that has a needle side running to the needle. The apparatus comprises a stationary knife, a spring positioned below the stationary knife and biased in a direction toward the stationary knife, and a movable knife slidably mounted between the stationary knife and the spring which yieldingly urges the movable knife thereagainst. The movable knife has one penetrating end with a pair of axially offset barbs, a lagging barb and a leading barb closer to the penetrating end of the movable knife than the lagging barb. These three elements cooperate to hook and sever the needle side of the needle loop and the looper thread below the needle plate and prepare the looper thread for the next stitch.

Abstract: The invention herein described comprises a programmable microprocessor control unit 2 controlling a plurality of actuators 6, 7, 8, 9, 10, respectively associated with the differential feed dog, main feed dog and upper feed dog and/or with the presser foot and the tension group of an industrial sewing machine 5. On the basis of the adjustment parameters keyed-in in said control unit, each actuator individually causes the adjustment of the movements of each feed dog, of the pressure exerted by the presser foot and of the force causing the dish-shaped elements of the tension group to be moved close to each other to retain the threads interposed therebetween.

Abstract: A thread control device for the looper thread of a chain stitch sewing machine having a rotating thread take-up disc and a cover plate containing a slot for the thread take-up disc. To prevent broken thread being wound up on a main shaft, a tube carrying a pressure medium, such as a stream of air, is disposed between the thread take-up disc and a looper eye. Tension is thereby mantained in the looper thread even if the thread breaks downstream of the thread take-up disc.

Abstract: A plurality of tension disk assemblies in an overedge sewing machine are disposed on a shaft supported for rotation around its axis and are spaced apart from each other in an axially distributed relationship. Each tension disk assembly comprises first and second tension disks forming a pair for holding therebetween a thread to be tensioned. The first tension disk is movable in opposite directions axially of the shaft, and the second disk is substantially immovable in the direction of the axis of the shaft. The resilient force of a spring acts on each first tension disk, whereby the latter is pressed against the second tension disk associated therewith. When the shaft is turned, as by a manual operating lever, this rotary motion is converted into a linear motion through a cam device. This linear motion removes the resilient force of the spring from the first tension disk. Thus, a thread tension released state is established simultaneously in the plurality of tension disk assemblies.

Abstract: An automatic thread tensioning device for positioning the crossing points of upper and lower threads in the center of thickness of a fabric undergoing stitching. The positioning is effected by making calculations based on measured results of thread tension, without needing to detect the various kinds of characteristics of fabrics, threads, or lower thread tension responding to an existing type of stitching condition. The proper upper thread tension may be determined for the stitching conditions of fabrics which have different characteristics and for stitching conditions of fabrics which have conventionally been difficult to deal with, simply by pressing buttons and making test stitchings. If an upper thread tensioning device has a motor, a stitching operation may be made more easily.

Abstract: A demand responsive sewing machine thread take-up construction is disclosed accommodating a shortened thread introduction path which facilitates operator interface and reduces construction costs while providing for improved reliability and uniformity of thread manipulation by the take-up.

Abstract: A sewing machine system is disclosed for accurately controlling the amount of supply of a needle thread to a thread take-up member from a thread supplying source in response to various conditions of sewing.The system controls supply and withholding of the needle thread with an accurate timing by putting an electrostrictive element into operation or non-operation in relation to a parameter signal on sewing conditions and a synchronizing signal derived from the timing of rotation of the arm shaft of sewing machine.

Abstract: A thread tension control device for overedging sewing machines wherein each needle thread tension controller and each looper thread tension controller provide two springs designed to clamp two tension discs wherethrough a thread is passed. A slide plate, by its horizontal sliding motion, either causes the two springs to be active or causes one of the two springs to be released thereby obtaining either strong or weak thread tension. A workpiece end detector defines either an overedging process or thread chain forming process and sends a signal to actuate the horizontal sliding motion of the slide plate. Thus, the proper thread tensioning for each needle thread and each looper thread for either an overedging process or a thread chain forming process may be automatically adjusted.

Abstract: A looper assembly for a two thread bag closing sewing machine in a simple arc within a single plane on one side of a moving needle, the plane being parallel to the needle axis and intersecting the line of movement of the bags at an angle of less than 45 degrees to reduce thread wear and breakage. A process of stitching the bags utilizing looper movement within a single plane is also disclosed.

Abstract: A lower thread tension device is provided in association with adjustment of an upper thread tension device in such a manner that when the tension of the upper thread tension device is strong within an adjusting range, the lower thread tension is adjusted strongly, and when the tension of the upper thread tension device is weak within the adjusting range, the lower thread tension is adjusted weakly. The upper and lower thread tension device includes a dial for adjusting an upper thread tension, a potentiometer connected to the dial, and an electromagnet with an actuator acting on the lower thread to adjust its tension in response to a signal received from the potentiometer due to rotation of the dial. The upper and lower thread tension device includes a dial for adjusting an upper thread tension, a potentiometer connected to the dial, and an electromagnet with an actuator acting on the lower thread to adjust its tension in response to a signal received from the potentiometer due to rotation of the dial.

Abstract: This invention makes a proper calculation to an amount of supplying a lower thread to be required to forming of a stitch with stitching information in relation with changing of a needle dropping position from a preceding stitch to a present stitching, so that the lower thread is forcibly drawn out in accordance with said calculation, and makes a proper calculation to tension of an upper thread optimum to forming of a stitch with stitching information so as to determine the optimum upper thread tension in accordance with said calculation, or makes a calculation to the amount of supplying the upper thread optimum to forming of a stitch with stitching information so as to draw out the upper thread in accordance with said calculation.

Abstract: A sewing machine is equipped with a needle thread tensioning device which has two gripping discs mounted on a pin. The gripping discs are connected via a spring mechanism with two adjusting members on the same axis capable of movement relative to one another, of which at least one is mounted on a threaded section of the pin. In addition, the tensioning device has a mechanism for occasional suspension of the effect of the spring. With the tensioning device, in spite of the common mounting of both the adjusting members on the same pin, two tensions of varying degrees, a main tension and an auxiliary tension, can be adjusted and transmitted to the needle thread independently of one another and quickly switched one for the other. For this purpose, the two adjusting members are designed as inner and outer parts and separated from one another by a stationary support placed between the inner and the outer part.

Abstract: An automatic thread tension adjusting device for a sewing machine designed to automatically adjust the tension of upper thread to produce desired stitches each formed with the upper and lower threads interlocked with each other within the thickness of a fabric to be sewn, the interlocking position of the threads depending upon the types of stitches such as the straight stitches and zigzag stitches. The thread is held and drawn-out at predetermined angular positions of an upper drive shaft, which are detected by sensors to thereby draw out a required amount of upper thread depending upon the thickness of the fabric and the type of stitches. The required amount of the upper thread is supplied to a thread take-up lever to determine the upper thread tension during the formation process of each stitch.

Abstract: A device for regulating upper thread tension in a sewing machine having an upper thread tension device with two discs receiving an upper thread therebetween, a spring pressing the discs one against the other, a presser body positioned between the spring and the discs, and a manually operated dial for actuating the presser body, the regulating device having an indicator for indicating a thread tension of a proper value and operatively connectable to the dial and movable thereby, in which a relation between a moving amount of the presser body and a moving amount of the indicator is regulated and a pressure of the thread tension is adjusted to the movement of the thread tension indicator.

Abstract: A slit (7) is formed which lies in a vertical plane and extends from an upper surface of a sewing machine frame (1) to a front surface. A tension device (5), a thread take-up spring (30), and upper and lower thread guides (23, 24) are disposed along the direction in which the slit (7) extends. A thread take-up lever (12) is installed so that it is reciprocated horizontally across the space between the pair of thread guides (23, 25). The placement of the thread in the tension device (5), thread take-up spring (30), and two thread guides (23, 24) can be attained by simply pulling the upper thread vertically downward through the slit (7). When the thread take-up lever is reciprocated, during its forward stroke it arrests the portion of the thread positioned between the two thread guides (23, 24) and draws it in V form. During its return stroke, the thread take-up lever (12) releases the thread to allow the latter to loosen in loop form.

Abstract: There is provided an automatic sewing machine which comprises, a main shaft, a bed, a needle bar having a needle secured to the lower end thereof, a thread straining control device, an operation device and an alarm device.

Abstract: The frame of a sewing machine is divided into a rear frame section (1) and a front cover (2). Mounted on seats formed on the rear frame section (1) are such components as an arm shaft unit (4), a loop taker unit (10), a presser and needle bar unit (3) and a bottom arm shaft unit (8). Mounted on the front cover (2) are a bobbin winder (60), operating panels (83, 84), control knob (68), etc. A pattern selecting dial (26), a reverse lever (32), a work feed control dial (87), etc. are held by mechanism components mounted on the rear frame section (1) and are exposed to the outside through openings (61, 62) in the front cover (2).

Abstract: A tension setting device of the sewing machine comprises an upper thread tension device on the machine frame. A selecting device for selecting a thread tension in response to a thickness of a fabric being sewn is mounted to the machine frame. An auxiliary upper thread tension device cooperating with the selecting device and actuated thereby to adjust upper thread tension in response to the thickness of the fabric is provided in the tension setting device. A lower thread adjusting device cooperates with the thread tension selecting device to adjust the lower thread in response to the thickness of the fabric being sewn.

Abstract: A thread tightening control apparatus according to the present invention is capable of tightening upper and under threads accurately and in good order, irrespective of fabric thickness, by the relative movement between a needle and a fabric holding body.The apparatus is provided with setting means capable of generating a plurality of setting signals of different timings at which the drive pulses are to be supplied to the drive means in dependence upon fabric thickness. Shifting means is operable in association with a selected setting signal for moving a period during which drive means is supplied with drive pulses by the actuating means forward or backward with respect to a predetermined rotational angle of a spindle. As a result, the distance between the tip of the needle and the surface of the fabric at the completion of fabric feed is set to a predetermined minimum length irrespective of fabric thickness.

Abstract: A thread tension device of a sewing machine having a fabric presser bar lifting lever, comprises a mount plate fixedly arranged in the sewing machine, a support shaft having one end secured to said mount plate, a pair of first and second thread tensioning disks coaxially mounted on the support shaft and having concentrically arranged curved thread clamping faces which are pressed against each other to clamp therebetween an upper thread of the sewing machine, a spring operated to adjustably press the disks against the mount plate, a thread tension adjusting member operated to increase or decrease an elastic force of the spring, an actuating plate and a transmission rod having one end connected to the actuating plate and the other end operatively connected to the fabric presser bar lifting lever.

Abstract: A method of automatically adjusting thread tension in a sewing machine including detecting changes of load subjected on the needle bar caused when the needle penetrates the fabric to be sewn and adjusting the electric driving part of the thread tension device in accordance with the values of the changing components of the load.

Abstract: A thread tensioning device, wherein a helical spring of varying diameter is deflected by a control knob with a defined operating range to increase tension in sewing thread moved through the device, is provided with a member which is formed to engage one or more intermediate coils of the spring while the spring is deflected more than a predetermined amount by the control knob and thereby increase thread tension obtainable over a portion of the operating range of the knob.

Abstract: A lockstitch sewing machine is provided with a thread handling device comprising opposing lengths of cloth that receive and frictionally engage thread therebetween to maintain the takeup of the machine thread and impose restraint upon the descent of the thread when the takeup is moved downwardly from a stitch setting position.

Abstract: The needle of an individual embroidery location of a multitude or row of linearly arranged embroidery locations in an embroidery machine is mounted at an axially displaceably guided needle carrier. According to a programmed control and by means of a related switching lever the needle can be individually coupled to or decoupled from an oscillating drive rail which is common to all the needles of the row. A thread guiding roller which is journaled for free rotation at a roller supporting lever and associated with a related one of the needles supplies a thread to the related needle. Simultaneously with the coupling or decoupling of the needle to the oscillating drive rail the roller supporting lever is pivoted between an operative position and an inoperative position in which the thread guiding roller is respectively coupled to or decoupled from a braking member which is common to all embroidery locations.

Abstract: A sewing machine has a loop taker rotated in horizontal plane and a bobbin carrier contained in the loop taker. The bobbin carrier has an abutment secured thereto and a leaf spring mounted on the abutment and movable to and away from the abutment to adjust a tension applied to a lower thread extending between the abutment and the leaf spring. A plurality of windings are provided on a stationary horizontal plane adjacent the underside of the loop taker. The windings are progressively energized by selective operation of an electric control part to create a revolving magnetic field. A magnet is rotated in accordance with the revolving magnetic field, and the rotation of the magnet is transmitted through a series of gears to a cam which actuates a member influencing the movement of the leaf spring, thereby adjusting the tension applied to the lower thread.

Abstract: A work clamp shifting mechanism for a four hole button sewing machine in which operator influenced cam shifts the work holding jaws between two detent retained positions and also releases the thread tension during each shift between detent positions to defer the work from being disoriented in the work holding jaws.

Abstract: An electromagnetic driving device is provided at a non-rotating part of a sewing machine, thereby to rotate a first magnet via transmission mechanism. A second magnet which is opposite to the first magnet with an appropriate space thereby, is rotatably provided with respect to a bobbin carrier. These magnets keep a certain one rotating relative position by means of the opposing magnetic poles, thereby to transmit rotation of the first magnet to the second magnet. Rotation of the second magnet actuates a tension adjusting mechanism comprising a thread tension adjusting spring provided on the bobbin carrier, via the transmission mechanism so as to adjust the thread tension, and controls the electromagnetic driving device in response to designation of the thread tension. Thus, the tension of the lower thread may be adjusted when attaching the bobbin carrier in the sewing machine.

Abstract: A thread tensioning module and a cover for a thread holder and cooperating take-up are mounted adjacent to one another in a front opening in the bracket arm housing of a sewing machine. The module and cover form interconnecting thread receiving slots in the bracket arm opening providing for the movement of thread into thread tensioning mechanism carried by the module and into the thread holder as the machine is threaded by an operator.

Abstract: A thread tightening device for a sewing machine of the type having a main shaft, a vertically reciprocable needle bar with a needle carrying an upper thread, a loop taker and a drive shaft for driving the loop taker and a feed dog; the thread tightening device includes a group of pattern cams operatively connected to the main shaft, pattern selecting device and an arrangement for controlling the vertical movement of the feed dog. This arrangement comprises a control cam and a rotatable shaft, the control cam being slidably axially mounted on the rotatable shaft but not turnable with respect to the shaft. The thread tightening device also includes an element arranged for vertical reciprocating movement in a timed relation with the feed dog, which element engages a lower thread during the stitching operation of the sewing machine.

Abstract: A needle thread control mechanism for sewing machines which permits a machine operator to adjust the stitch tightness includes a thread take-up mechanism arranged wholly outside of the machine frame and a thread controlling mechanism arranged directly between the needle thread take-up mechanism and a thread supply source. A thread controller, adapted to cooperate with the thread take-up mechanism, is also provided.

Abstract: A thread tensioning module for use on a sewing machine is provided with a plastic housing and with mechanism at the rear of the housing for receiving and applying frictional resistance to the movement of thread therethrough. The mechanism includes a pair of thread engageable members, one of which extends beyond the other and the side wall of the module on the thread entering side thereof to catch and enable thread to be positioned between the members.

Abstract: A sewing machine having two needles supported in a needle holder, which needle holder is horizontally displacable, to present one needle to an active workstation in a prethreaded manner and simultaneously shift the other needle which has a different thread therein, into an adjacent inactive position. As the needles are being shifted, the needle moving to inactive status has its thread clamped against the needle holder by a wheel, to secure the thread from being pulled therefrom or straying. A vacuum tube arranged at each respective inactive position or station sucks the tail of the thread therein. A pair of thread guides, one for each thread, are arranged for vertical movement, to pullback on the dangling thread of the inactive needle, to prevent the thread from whipping during its inactive status. Each thread passes around a thread engaging wheel comprising a dual bobbin monitor arranged on a single axis.

Abstract: An assembly for adjustment of lower thread tension for a sewing machine having a loop taker and a bobbin carrier which is held by the loop taker and carries a bobbin loaded with the lower thread. The assembly comprises a base plate and a resilient member, one end of which is connected to the base plate. A tension is given to the lower thread while the thread is passed between the base plate and the resilient member. A substantially L-shaped presser element having an upper vertical and a lower horizontal portion is provided for the assembly and is turnably attached to an inner wall of the bobbin carrier. The vertical portion of the presser element is adapted to press a free end of the resilient member against the base plate. A permanent magnet or electromagnet acts on the horizontal portion of the presser element without contact thereto.

Abstract: A sewing machine is provided with a thread handling device including an elongate rigid member and a strip from which resilient fibers extend outwardly to contact thread passing between the rigid member and strip, and with a thread engaging cam which prevents a premature descent in said device and improperly formed stitches resulting therefrom.

Abstract: A thread handling device including an elongate rigid member and a strip with fibers extending outwardly to contact thread in a sewing machine passing between the rigid member and strip is provided with bracketing thread controlling cams which improve the performance of said device.

Abstract: An automatic thread setting device for electronically controlled material and needle position type sewing machines. The device has pattern selecting means, cloth thickness designating means, upper and lower thread tension adjusting means, and electronic memory means. Selection of a pattern automatically sets the thread tension. Selection of a different pattern automatically resets the tension.

Abstract: A thread tensioning device for a sewing machine is provided with a rigid beam which pivots on an adjustable fulcrum in engagement with a mounting plate. The device includes an adjustable tension selector movable along the plate and beam for varying the tension on needle thread disposed between the plate and beam.

Abstract: In a double-needle lock-stitch sewing machine, an assembly for arresting threads being drawn from the needles by an uptake stroke of a thread lever, thereby ensuring predetermined lengths of thread at the needles for an ensuing stitch, comprises a spring-loaded clamp disposed between the sewing lever and the needles. The clamp is periodically actuatable via a system of levers in the sewing-machine head by a cam mounted on the sewing-machine base and cooperating with a radial lug on a shaft driving a rotary thread gripper and bobbin holder. A spring-loaded plate engaging a pair of thread-tension control disks is pivotable by the lever system to release the disks upon actuation of the clamp. The clamp is particularly useful in controlling the length of a leading thread portion prior to beginning a sewing seam.

Abstract: A sewing machine is provided with a thread handling device having a thread holding and a thread metering function. The device includes a pair of parallel elongate members, and a length of easily compressible resilient material which is carried by one of the members and compressed against the other member. Needle thread extending between the resilient material and said other member is subjected to frictional resistance by the resilient material during movement in the device.

Abstract: A thread tightening device for a sewing machine of the type having a main shaft, a vertically reciprocable needle bar with a needle carrying an upper thread, a loop taker and a drive shaft for driving the loop taker and a feed dog, the thread tightening device includes a group of pattern cams operatively connected to the main shaft, pattern selecting device and an arrangement for controlling the vertical movement of the feed dog. This arrangement comprises a control cam and a rotatable shaft, the control cam being slidably axially mounted on the rotatable shaft but not turnable with respect to the shaft. The thread tightening device also includes an element arranged for vertical reciprocating movement in a timed relation with the feed dog, which element engages a lower thread during the stitching operation of the sewing machine.

Abstract: A thread tension control system for a sewing machine comprises the following elements arranged in sequence in a path of thread travel extending between the thread supply and needle of a sewing machine, an infinitely variable thread tension control device; a tortuous path thread tension control device; a check spring; and a take-up arm. The tortuous path thread tension control device comprises a generally cylindrical thread tension control post for receiving at least one wrap of thread, the thread tension control post being disposed approximately orthogonal to the path of thread travel. The tension control post is disposed in the path of thread travel between the infinitely variable thread tension control device and in the check spring to effectively multiply the tension provided by the infinitely variable thread tension control device and insulate the same from changes in pressure along the stitch line.

Abstract: An electronic thread tension control device whereby electrical signals indicating the fabric thickness, the amount of fabric being fed, the needle's amplitude and the size of the thread to be used are transmitted to the control circuitry thereby producing the appropriate output signal that will adjust the tensioning means accordingly.

Abstract: A tension device for sewing machines is disclosed having thread tensioning discs and a linear actuator for applying a compressive force between the discs. The invention is characterized in that for any given tension setting of the device, the applied compressive force, or tension, remains constant regardless of any variations in the spacing of the discs due to variations in the thread thickness, up to the range of travel of the linear actuator.