Abstract: A shuttle body 3 having aloop seizing beak 10 for seizing a needle thread 9 is rotatably attached to a shuttle race body 2, pressed by a driver 4, and continuously rotated in a rotation direction B in synchronization with vertical motion of a needle 8. A bobbin case 5 in which a bobbin thread 12 wound around a bobbin 5 is accommodated is attached to the shuttle body 3. Under a state where the bobbin thread 12 is pulled out from the bobbin case 5, the shuttle body 3 is rotated, the needle thread 9 is seized by the loop seizing beak 10, the loop of the needle thread 9 is expanded along the outer face of the shuttle body 3, the loop of the needle thread 9 is passed over the shuttle body 3 and the bobbin case 5 so that the shuttle body 3 and the bobbin case 5 are passed through the loop of the needle thread 9, whereby the needle thread 9 is wound around the bobbin thread 12 and a stitch can be formed.

Abstract: A wall of an inner loop taker includes a guiding surface, a first vertical surface which extends continuously to an inward end of the guiding surface in a radial direction of the inner loop taker and is parallel to an axial line of a needle, and a second vertical surface which is formed on the inward side of the first vertical surface in the radial direction of the inner loop taker but closer to the axial line of the needle than the first vertical surface and which is parallel to the axial line of the needle. A first angle .theta.

Abstract: A bobbin which is housed in a bobbin case holder is held, as it is elastically pressed by a peripheral wall of a bobbin case. Passing through a gap which is created between an outermost portion of a flange of the bobbin which is disposed on an open end side of the bobbin case holder and an inner peripheral surface of the peripheral wall of the bobbin case and between the flange of the bobbin which is disposed on the open end side of the bobbin case holder and the inner surface of an end wall of the bobbin case, a bobbin thread which is wound around the bobbin is led outside through the bobbin thread leading hole which is formed in the end wall of the bobbin case.

Abstract: A wall of an inner loop taker includes a guiding surface, a first vertical surface which extends continuously to an inward end of the guiding surface in a radial direction of the inner loop taker and is parallel to an axial line of a needle, and a second vertical surface which is formed on the inward side of the first vertical surface in the radial direction of the inner loop taker but closer to the axial line of the needle than the first vertical surface and which is parallel to the axial line of the needle.

Abstract: A hook assembly includes a bearing rib on a bobbin case basket or at least a surface layer thereof composed of a synthetic resin, such as a liquid crystal polymer, which has properties such that the amount of the rotating friction generated between such surface layer and an inner surface layer of a groove shaped bearing raceway in which the bearing rib is fitted is lower, with no industrial sewing machine oil therebetween than such industrial sewing machine oil where to be provided therebetween. The hook assembly thus has good durability without any lubrication being provided. Accordingly, oil staining of threads and sewing materials by a lubricant is avoided, and sewing quality is enhanced.

Abstract: A bobbin case holder body and a track projection portion are made of steel. A coating member of a liquid crystal polymer is integrally molded to the outer surface of the track projection portion so as to have a thickness t which is selected to be 0.3 to 0.5 mm. A part of the coating member is fitted into a groove formed in the track projection portion, thereby preventing the member from peeling off. In a loop spreading portion, the track projection portion made of steel is exposed from the coating member so that a so-called thread handing area is prevented from being formed. Therefore, wear resistance and durability are improved.

Abstract: The friction coefficient between a track projection of an inner bobbin case holder and a track groove of an outer loop taker is reduced so that the outer loop taker can be rotated a small torque. One portion of the inner bobbin case holder opposite to a needle location is made of a synthetic resin or a synthetic resin containing metal powder carbon fiber, glass grains, ceramic powder or the like.

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: An oscillating loop taker includes a bobbin case holder having a needle thread guiding projection which with a wedge forms a recess in which fits a driver member. A radial dimension from an axis of rotation of the holder to an inner leading edge portion of the projection is less than a radial dimension from such axis to an inner surface of the holder defining a space within which is housed a projection. The inclination of a needle thread guide face at the recess side of the projection is set to a desired comparatively large value. The circumferential length of the needle thread guide face is made comparatively long to enable a needle thread to be easily transferred onto the outer circumferential face of the bobbin case. Thereby, the bobbin thread is permitted to pass between the inner peripheral face in the vicinity of the base end portion of the projection and the outer peripheral end portion of the bobbin case.

Abstract: An electromagnet including a coil unit having a plurality of electrically insulative substrates, each having a spiral conductor formed thereon, the substrates being stacked together with the spiral conductors parallel with each other. The conductors of the unit are connected in series with each other so that magnetic fluxes formed of electric currents flowing through the conductors are directed in the same direction at the central positions of the spirals of the spiral conductors, and there are formed holes at the central positions for receiving a ferromagnetic core which is moved in response to a direct electric current passed through the coil unit. A valve may be connected to the ferromagnetic core to form an electromagnetic valve assembly.

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.