Abstract: A bobbin holding member magnetically adheres within a bobbin case holder which houses a bobbin. The bobbin is securely retained in the bobbin case holder without allowing the bobbin to be removed therefrom during a sewing operation. The bobbin holding member is installed in the bobbin case holder freely detachably, and thus the bobbin easily can be replaced.

Abstract: The amount of a bobbin thread wound in a bobbin of a full rotary hook is increased by making a circumferential portion of a bobbin case holder between a thread separating portion and a thread releasing portion thinner than the remainder of the circumference, thereby increasing the inner diameter of the bobbin case holder. Thereby, the inner diameter of the bobbin housed in the bobbin case holder and the inner diameter of the cylindrical portion housing the bobbin case can be increased and consequently an outer diameter of a flange of the bobbin can be increased, thereby increasing the amount of the bobbin thread wound around the bobbin.

Abstract: A fully rotating hook includes an inner bobbin case, an outer loop taker mounted about the bobbin case, the loop taker having a track groove formed therein, a rotating member for rotating the loop taker such that relative rotation occurs between the loop taker and the bobbin case, and a stopper member for preventing rotation of the bobbin case with the loop taker while the loop taker is rotating. The track groove of the loop taker is formed by at least one wall therein which is coated with a layer of synthetic resin material having a small coefficient of friction to reduce friction between a track projection member on the bobbin case and the track groove of the loop taker.

Abstract: A rotary looper for a lockstitch sewing machine, which can receive either a coreless thread package or a thread-wound bobbin. An upper bobbin-housing part is provided with two separate thread-tensioning elements and with respective thread-guide slots associated with them. In this way, the thread withdrawn either from a coreless thread package or a looper-thread bobbin passes over an optimally-shaped thread path on its way to the sewing area, and in both cases, a specifically adapted thread-tensioning force is exerted on the thread withdrawn. Preferably, the front part of the thread supply, in the coreless package or bobbin, can be accommodated in front of the movement path of the sewing needle, whereby the bobbin-housing can accommodate an extra-wide thread supply. An upwardly extended shoulder is provided on the lower part of the bobbin housing, so that the axially widened needle thread loop can slide unimpeded over the axially-extended bobbin-housing upper part.

Abstract: A sewing machine has at least one rotating top thread hook, the hook enclosing a bobbin housing which accommodates a bottom thread. A spring bar is mounted in the base of the sewing machine and has a free end for bearing against the bobbin housing. The free end of the spring bar is displaceable by the top thread as it is being looped. To prevent unwanted displacement or oscillation of the spring bar, a cam is disposed in the base closely adjacent to the free end of the spring bar. The cam prevents displacement of the free end beyond a predetermined range of displacement.

Abstract: A rotary looptaker includes a looptaker body rotatable about a vertical axis and a bobbin case restrained from rotary motion with the looptaker body. A plurality of annular protrusions are provided on a flange of the bobbin case so as to extend in a circumferential direction of the bobbin case and are in engagement with a flat surface formed on a raceway of the looptaker body. When the looptaker body is rotated, the bobbin case slides relative to the looptaker body through a very small contact area between the annular protrusions and the flat surface, thus reducing sliding friction between the looptaker body and the bobbin case. Accordingly, noise and vibration are decreased when a rotation restraining projection of the bobbin case contacts a restraint element secured to a machine frame.

Abstract: A loop taker comprising a bobbin case holder in which is housed a bobbin whose axis is inclined relative to the rotational axis of a cup-shaped hook body in such a way that the bobbin is kept away from a path of needle movement, and also a sewing machine equipped with the loop taker. Thereby, it is possible to increase the outer diameter of the bobbin or increase the length of the bobbin, and it is possible to increase the quantity of bobbin thread wound on the bobbin.

Abstract: A horizontal lock-stitch bobbin basket includes a cylindrical side wall, a laterally extending flange formed at the top of the side wall, and a rotation restraining notch formed in the top face of the flange. An elongated bore is defined by the side wall adjacent the restraining notch to provide for needle clearance. The bobbin basket is made of plastic and includes a needle guarding member the (1) protects the area of the bobbin basket adjacent to the bore from being accidentally damaged by the needle of a sewing machine, and (2) deflects the needle into the elongated bore.

Abstract: A sewing machine having a thread monitor associated with a bobbin mounted for rotation. The bobbin includes first and second reflecting surfaces associated with an inner side of a second bobbin flange, and first and second light outlet openings associated with a second bobbin flange. A light source is provided for directing light toward the reflecting surfaces. A light receiver is positioned so as to receive light emerging from the first and second outlet opening. The light receiver produces signals representing the light intensity received by the light receiver. A Schmitt trigger provides a pulse to a microprocessor coinciding with a revolution of the bobbin. For each revolution of the bobbin, an A/D converter converts signals received from the light receiver into digital signals which are compared. The digital signal having the maximum value for the revolution is stored in a memory and then compared with a subsequent maximum value.

Abstract: A sewing machine with a lockstitch rotary hook containing a bobbin, has a thread monitor with which light signals of a radiation source are conducted to a light receiver via inlet and outlet openings in parts of the rotary hook and in at least one of the flanges of the bobbin. For determination of a predeterminable thread and length, the hub which connects the flanges of the bobbin comprises a truncated cone-shaped region, in the surface of which the outlet opening extending substantially parallel to the axis of the hub ends.

Abstract: A lubricating device for a revolving lock stitch shuttle of machines such as sewing and embroidering machines comprises a shuttle body which has a hub portion which surrounds its associated shuttle arbor and which lies adjacent a bearing mounting for the arbor. The hub portion is hollow and defines a lubricating oil chamber between it and the associated bearing and a gap between the shuttle hub portion and the associated bearing is bridged by a fixed ring member which is carried on a bracket which is secured to the bearing. The ring member has an opening therethrough providing an access for a nozzle tube for feeding oil from an external reservoir to the hub recess from when the oil is advanced by the centrifugal force of the rotation of the shuttle to the periphery of the shuttle.

Abstract: A fully rotating hook includes an inner bobbin case, an outer loop taker mounted about the bobbin case, the loop taker having a track groove formed therein, a rotating member for rotating the loop taker such that relative rotation occurs between the loop taker and the bobbin case, and a stopper member for preventing rotation of the bobbin case with the loop taker while the loop taker is rotating. The bobbin case includes a case body having a bottom and accommodated in the loop taker, and a track projection member made of synthetic resin material having a substantially small friction coefficient and removably fixed to the case body. The track projection member includes a flange-like track projection fitting within the track groove of the loop taker and a surrounding portion for surrounding the bottom of the loop taker.

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 lockstitch sewing machine includes a rotary hook. For the rotation secure retention of the bobbin housing of the hook, two cams are arranged in the central region of the loop cast-off side, which receive a spring rod between them. A shoulder formed at the bobbin housing is associated with the cam or with the spring rod. Through the special position of the cams, the movement resistances during the guiding of the needle thread loop around the bobbin housing is reduced to a minimum.

Abstract: A thread-tensioning device for being mounted on a bobbin housing, the bobbin housing having an upper part and a lower part which define a space for receiving a bobbin, and a jacket for substantially surrounding the bobbin. The thread-tensioning device includes a thread-tensioning member, such as a lever, having a first end swingably supported on the upper part of the housing, and a second end comprising a finger for bearing on the thread package on the bobbin. A central part of the lever is received by a slot in the jacket of the bobbin housing. A leaf spring bears upon the lever to urge the finger toward the interior of the bobbin-receiving space and against the thread package. The arrangement produces a detaining force and a braking force which combine to result in a relatively constant thread-tensioning force.

Abstract: A rotary looptaker having an annular groove formed therein and a bobbin case having a track rib formed thereon, wherein the looptaker is driven for rotation with the annular rib fitted into the annular groove and permanent magnetic pieces are respectively provided in the annular rib and the annular groove so that magnetic repulsive forces are produced therebetween.

Abstract: A lockstitch sewing machine includes a rotary hook, with a bobbin housing and a cam is provided for the rotation-secure retention of the bobbin housing and it is arranged a small distance behind the stitch hole in the direction of hook rotation. A holding finger for holding the bobbin housing against rotation with the hook body projects from the bobbin housing, as well as a supporting finger arranged substantially 90.degree. before the stitch hole. A shoulder projecting from the bobbin housing is associated with the supporting finger.

Abstract: A rotary hook assembly including a bobbin case basket, for therein accommodating a bobbin case containing a bobbin having bobbin thread wound therearound, on the outer periphery of which there is formed a guide rim. A rotary hook, for therein accommodating the bobbin case basket, has a guide groove formed on the inner periphery thereof. A metal hard-facing coating layer is applied on the outer periphery of the bobbin case basket, the inner periphery of the rotary hook, and/or the outer periphery of the bobbin case by utilizing an ion-plating method.

Abstract: A displaceable cover for the housing of a sewing machine loop catch mechanism comprises a plate fixed to a pin which in turn is rotatably and slidably mounted in relatively fixed bearings. A spring element exerts upon the pin both a torsion torque and downward axial thrust. Opening of the cover is accomplished by depressing one end of a pivoted lever to cause the other end thereof to raise the cover from engagement within the housing and allowing the spring elements to swing the cover into an open position.

Abstract: A fully rotating hook includes an outer member or rotary loop taker having a track groove therein and an inner shuttle member or bobbin case a projection extending into the groove. A spaced relation between the track groove and the projection is maintained by feeding compressed air into a clearance therebetween.

Abstract: A rotary hook for a sewing machine has a rotatable hook drive shaft driving a hook body in cooperation with a reciprocating needle which moves toward and away from the rotary hook. The hook body has a revolving rotary hook tip which is movable in a path relative to the needle and is engageable with the thread presented by the needle. The rotary hook includes a thread deflecting shoulder to enlarge the thread to form a needle thread loop, includes a case holder having an annular guide rib and a pin extending axially outwardly of the holder. A bobbin case has a central hollow sleeve into which the pin extends and a latch engageable with the pin to hold the case holder to the bobbin case. The case each holder and the bobbin case have a sidewall with interiors which are in substantial alignment. The bobbin case holder has a rearwall formed as a substantially truncated cone which is eccentric to the guide rib and the bobbin case has an annular sidewall and a frontwall have an arched mushroom shape.

Abstract: A lower thread tension adjusting device is disclosed, which is used in combination with a sewing machine having a horizontal rotary loop taker and a stationary bobbin carrier accomodating a bobbin. A lower thread drawn from the bobbin is passed between a base plate secured to the outer face of the bobbin carrier and the free end of a resilient plate having one end secured to the base plate, so that by manipulation of an adjusting screw a variable degree of tension can be applied to the lower thread. The device is so designed that when an index provided on the adjusting screw is in alignment with a reference mark of the base plate, the lower thread will be given a predetermined standard value of tension.

Abstract: A stopper device for a lock stitch sewing machine includes a retaining member having a contacting face and which is moved in the downstream direction, with respect to the rotary running direction of the loop taker, when a needle thread loop passes between a contacting face of the bobbin case and such contacting face of the retaining member. This facilitates the passing of the needle thread loop. An arrangement returns the contacting face of the retaining member in the upstream direction.

Abstract: A mechanism for allowing adjustment of a cushion spring assembly to vary the distance between the wall of the bobbin case and the cushion spring in two directions. Means are incorporated to permit movement of the cushion spring assembly to facilitate removal of the bobbin case from the loop taker, without affecting the adjustment of the mechanism.

Abstract: A bobbin case, which is loosely confined within the looptaker of a sewing machine, is biased both into engagement on one side against the looptaker and about the looptaker axis toward a position of engagement with a stop by a continuously engaging light force applying resilient member, and a shock absorber is disposed for engagement with the bobbin case only upon movement thereof through a predetermined distance in opposition to the bias of said resilient member.

Abstract: A rotating sewing machine hook (1) with a horizontal shaft in which the axis of the under thread bobbin (15) forms an angle (a>0) to the hook shaft in a horizontal plan, whereby the width of the bobbin can be increased without the use of thread guide plates, because the inclination of the bobbin in the bobbin holder (6) facilitate the passage of the upper thread around the bobbin holder.

Abstract: A hanging bobbin case in a sewing machine having a horizontal axis rotating hook is disclosed. The weight of the bobbin case is vertically supported by a finger portion of a bracket which is hingeably attached to the machine frame for easy removal of the bobbin. Projections formed in the bracket limit sideways movement of the bobbin case for preventing contact with the interior walls of the hook.

Abstract: In a horizontally rotating looptaker for a sewing machine having a bobbin case mounted for relative rotation on a raceway within a rotating cup-shaped hook body a magnet is carried by the bobbin case adjacent the outer periphery thereof and a fixed member of magnetic material is disposed in close, non-contacting relation to said magnet to continuously bias said bobbin case into engagement with the raceway to prevent the occurrence of undesirable noise.

Abstract: A non-spill bobbin case device having a bobbin thread tension spring and a direct bobbin thread path extending from the bobbin thread tension spring across the bobbin case device spaced from the outer face of a bobbin flange supported in the bobbin case, and having a leaf spring with a first end attached thereto, the second end of which impinges upon the outer face of the bobbin flange. An indirect thread path is established by reeving the bobbin thread through a hook provided on the end of the leaf spring in engagement with the bobbin flange so that upon thread demand, the leaf spring is removed from the bobbin flange to permit free rotation thereof; but when thread demand ceases, the end of the leaf spring comes immediately into contact with the bobbin flange to deter further rotation thereof.

Abstract: A non-rotatable, disc-like bobbin carrier is nested in a cup-shaped, vertical axis, rotary loop taker that slidably supports the bobbin carrier at its periphery on an annularly extending, discontinuous lip constituting a circular race slightly offset eccentrically from the loop taker axis of rotation. As the loop taker rotates, the eccentrically positioned bobbin carrier jogs back and forth in reciprocating fashion against one and then the other of a pair of diametrically opposed fixed stops that cooperate to preclude rotation of the bobbin carrier. The movement of the bobbin carrier away from and against each stop is synchronized with movement of a thread loop about the bobbin carrier to permit free passage of the loop between the fixed stops and the moving bobbin carrier.

Abstract: A bobbin case positioning and retaining structure of one piece unitary construction for maintaining the bobbin case in proper operating position. The bobbin case is held captive without the need for operator manipulatable locking devices.

Abstract: A sewing machine bobbin case is provided with a thread tensioning device that includes a pivotally movable arm which is spring biased into a position preventing thread from entering the device during the sewing of materials on the machine, but which is disposable by a finger in a position providing for the introduction of thread into the device in preparation for the performance of a bobbin winding operation.

Abstract: An internal housing comprises an upper part 1, a lower part 3 and a middle part 2. The middle part 2 connects the internal housing to an external housing 4 to form a rotary loop taker. The external housing 4 comprises an elastic piece 6 for engaging thread as well as a tail base 42 and an internally tapered ring 5 for fitting the loop taker into a sewing machine. The middle part 2 provides a ring about which the external housing 4 is rotatable, and to facilitate this rotation, this middle part is of or coated with Teflon.

Abstract: A variable pull-off mechanism for a sewing machine is provided with a thread pull-off disc on a rotatably mounted shaft which is concentric with the drive shaft of a vertical axis looptaker. The disc is formed with thread catching edges which engage and pull-off thread from a bobbin as the disc is oscillated between a fixed and a controllable position in accordance with the operation of a servomotor responsive to various control signals.

Abstract: A bobbin case for a shuttle having a rotary hook in which a plurality of pins for connecting an upper portion made of metal and a lower portion made of plastic are flexibly connected to the lower portion such that the pins may be slightly inclined upon contact between the upper portion and the pins due to vibrations transmitted from the rotary hook to the upper portion, thereby preventing generation of noise.

Abstract: A device for preventing the rotation of the bobbin case member of a horizontally fully rotatable shuttle comprises a retaining member adapted to contact one portion of the inner shuttle member for retaining the bobbin case member against rotation. One of the contact faces of the bobbin case member and the retaining member is partly formed with a recess. The retaining member is reciprocally movable along the contact face of the bobbin case member to prevent the rotation of the shuttle member and permit release of an upper thread free of resistance.

Abstract: A sewing machine for sewing workpieces, comprises a stationary bottom part with an arm which has one end pivotally mounted on the bottom part and an opposite end overlying the bottom part. The arm is movable from a fixed sewing position to an inoperable position away from the point of stitch formation. A revolving looper is mounted on the end of the opposite arm and it has a thread exit opening and a needle is mounted for upward and downward movement in the bottom part for cooperation with the looper. The workpiece is clamped between the base part and the arm and the needle traverses the workpiece upwardly. The construction includes a looper thread guide member mounted on the opposite arm adjacent the looper and has a thread deflector located between the needle path and the thread exit opening of the looper and extending above the point of stitch formation directly laterally of the needle path crosswise to the axis of the looper.

Abstract: A hook for a sewing machine comprising a hook body, a bobbin case holder arranged in the hook body, a bobbin case arranged in the bobbin case holder and a bobbin in the bobbin case. The bobbin case holder has a bottom wall from which extends a pin. The pin is provided with resilient check elements. A pin portion extends centrally from a bottom wall portion of the bobbin case defining a hole therein having a shape suitable to provide together with the pin of the bobbin case holder a locking system to lock the bobbin case to the bobbin case holder. A lever is positioned in the hole to ensure locking and release of the bobbin to and from the bobbin case. The bobbin is inserted in the bobbin case so as to close it upwardly.

Abstract: A bobbin thread tensioning device on a bobbin case is provided with a pair of bobbin thread accepting members, one of which is biased toward the other by an adjustable spring. The thread accepting members are disposed relative to each other and with respect to a rotatable hook to assure seizure of the bobbin thread by the hook beak.

Abstract: A lockstitch sewing machine is provided with a rotatable loop and bobbin case assembly providing for limited contact between the loop taker and bobbin case, and including a bracket which is affixed to the bed of the machine and is connected with the bobbin case at substantially diametrically opposite locations thereon to constrain the bobbin case angularly and rotationally but permit needle thread to be moved by the loop taker between the bobbin case and bracket during the formation of lockstitches.

Abstract: A bobbin case for use in machines having underbed thread trimmers incorporates a thread guide consisting of a piano wire soldered to the cylindrical skirt of the case in the region between the leaf tension spring and the point at which the thread is cut by the trimming blade. A groove is formed under and partly through the wire and also partly through the cylindrical skirt. The groove is directed at an angle to the longitudinal direction of the skirt such as to place the groove in line with the direction of movement of the thread to facilitate smooth thread handling.

Abstract: In a lockstitch sewing machine, a bobbin thread replenishing mechanism for selectively rotating the bobbin to wind replenishment thread thereon from a needle by means of a spindle selectively engaging the bobbin for rotating the bobbin with the machine looptaker wherein a slip clutch provided with an elongated slot is positioned around a flattened end portion of the spindle generally within a central aperture of a bobbin thread control cam. The slip clutch has an enlarged lower flange which rests on the looptaker base and rubs against the thread control cam so that by this arrangement the spindle will be driven with the looptaker by way of friction coupling of the slip clutch between the looptaker and the thread control cam. Should sufficient resistance of the turning of the spindle arise, the looptaker and thread control cam turn freely relative the slip clutch thereby preventing overwinding of the bobbin.

Abstract: A shuttle device provided with a rotating hook comprises a rotatable race secured to a verticle driving shaft. A bobbin carrier is journalled in the race and has a pair of spaced abutment faces on opposite sides of the path of the needle. The abutment faces cooperate with two spaced beaks on an oscillating escapement so that one of the beaks is always in contact with one of the abutment faces to prevent the carrier from rotating. The oscillation of the escapement permits a space to be left alternatively for each pair of cooperating beaks and abutment faces for the passage of the upper thread loop. The escapement is resiliently yieldable to prevent injury to the beaks or abutment faces, in the event of thread jamming between the sliding contact faces of the shuttle race and the bobbin carrier.

Abstract: A sewing machine having a semi-rotating looper assembly, characterized in that the driving mechanism for said semi-rotating looper assembly comprises a motor, a rotatable link, and a sector gear formed on said rotatable link. Said sewing machine further comprises a cloth-feeding mechanism including cloth-feeding teeth, a spring for biasing said cloth-feeding teeth in one direction and to a level below the plane of the cloth to be fed, and a swingable lever connected to said link. Said semi-rotating looper assembly includes a rotating looper holder opening in the table surface of the machine body, a slit formed in the inner peripheral wall of said rotating looper holder, and a rotating looper disposed in said rotating looper holder and having a bobbin holding portion and an edge. Said looper assembly further includes a driving mechanism for causing a partial reciprocatory rotary motion of said rotating looper within said rotating looper holder.

Abstract: A plate is provided in association with the bobbin case of a sewing machine for movement on a hinge between an open position in which the bobbin case can be readily removed from the bed of the machine, and a closed position wherein the plate holds down the bobbin case and prevents it from rotating while the machine is in operation.

Abstract: A sewing machine is provided with bobbin case restraining means including a pivoted member to engage and restrict movement of the bobbin case, and including a latch for the pivoted member, the pivoted member and latch being movable into a bobbin case restraining position during movement of a bed slide plate toward a closed position.

Abstract: A lock stitch sewing machine having a rotary loop taker adapted to carry a loop of thread about a stationary bobbin thread case. The bobbin thread case is restrained from rotation by a finger which is disposed between abutments in the bobbin thread case for opening a passage to allow the needle thread loop past the bobbin thread case rotation restraining means, the rotation restraining finger is vibrated at a frequency greater than four cycles per rotation of the loop taker.

Abstract: A sewing machine bobbin adapted for disposal in a bobbin case. The bobbin includes a hollow cylindrical core on which a thread mass is wound adapted for slidable disposal over a center post mounted in the bobbin case, and a latch is mounted on the post for securing the cylindrical core and the thread mass in the bobbin case, the post and the latch having a combined axial length greater than the axial width of the bobbin case. The improvement of the invention comprises constructing the hollow cylindrical core so that the edge of at least one end thereof is axially tapered radially inwardly along the axis of the core away from its end towards the center post of the bobbin case and has an axial length which is greater than the axial distance between the bobbin case and the latch. The thread mass is wound on the core so that the tapered edge extends axially outwardly along the core axis beyond the surface of the thread mass.

Abstract: A fully rotating hook .[.includes an outer member or rotary loop taker having a track groove therein and an inner shuttle member or bobbin case a projection extending into the groove. A spaced relation between the track groove and the projection is maintained by feeding compressed air into a clearance therebetween..]. .Iadd.assembly for a lock stitch sewing machine having an inner bobbin case for supporting a thread bobbin with a track projection extending circumferentially around the bobbin case, an outer loop taker mounted about the bobbin case and having a track groove extending circumferentially around an inner peripheral surface thereof and air passages for injecting compressed air into a clearance between adjacent surfaces of the projection and the groove. The air passages can be formed in the groove of the loop taker and in the projection.

Abstract: A rotary hook assembly including a bobbin case basket, for therein accommodating a bobbin case containing a bobbin having bobbin thread wound therearound, on the outer periphery of which there is formed a guide rim. A rotary hook, for therein accommodating the bobbin case basket, has a guide groove formed on the inner periphery thereof. A metal hard-facing coating layer is applied on the outer periphery of the bobbin case basket, the inner periphery of the rotary hook, and/or the outer periphery of the bobbin case by utilizing an ion-plating method.