Abstract: A single- or multiple-head embroidery machine has stitch-forming tools which are formed in each case by a thread-guiding needle that interacts with a double-lock-stitch gripper to form stitches, and also has a feed device for obtaining relative movements between the embroidery material and the stitch-forming tools. The relative movements occur depending on the movements of the needle. In order to avoid a temporal overlap between the stitch-forming phase and the feed movement of the embroidery material, the double-lock-stitch gripper rotates at a rotational speed which corresponds to n times the rotational speed of the machine main shaft, wherein “n” is an integer greater than the number “2”.

Abstract: A variable timing system for a sewing machine is provided comprising a shuttle hook having a hook tip, a first helical gear mounted on the shuttle hook, a lower shaft configured to rotate the shuttle hook in synchronization with a needle bar, and a second helical gear mounted on the lower shaft and capable of engaging with the first helical gear. In accordance with embodiments, at least one of the helical gears is axially movable. The variable timing system may comprise a control device configured to generate a control signal representative of a current sewing situation. A drive force mechanism may receive the control signal and in response, transmit axial movement to the axially moveable helical gear to move the gear into proper position relative to a threaded needle of the sewing machine.

Abstract: Rotary hook drive device for a sewing machine includes: a rotary hook rotatably provided on a rotary hook support; a cylindrical grooved cam provided on a drive shaft drivable to rotate in one direction; a cam follower engaged in a cam groove of the cylindrical grooved cam and capable of making reciprocative movement about a support shaft in response to rotation of the cylindrical grooved cam; and a transmission mechanism that transmits the reciprocative movement of the cam follower to the rotary hook to cause the rotary hook to make reciprocative pivoting movement. Such arrangements can prevent deviation in driving timing of the rotary hook and simplify the construction of the rotary hook drive device.

Abstract: A sewing machine including a head portion including a needle bar, the needle bar being for mounting a needle threaded with a needle thread; a principal shaft; a sewing machine motor for driving the needle bar via the principal shaft; a bed portion including a loop taker for taking a thread loop of the needle thread in cooperative operation with the needle; a loop taker drive shaft connected to move in association with the loop taker; a loop taker drive unit including a loop taker drive motor for driving the loop taker drive shaft independently of the principal shaft; a synchronization control unit for controlling at least one of the loop taker drive motor and the sewing machine drive motor so that the loop taker and the principal shaft rotate in synchronization; and an offset adjustment unit provided to the synchronization control unit and for adjusting an amount that the phase of the loop taker is offset from a reference phase offset amount preset for the loop taker with respect to the principal shaft.

Abstract: An embroidery machine having a plurality of beds and corresponding heads. In each of the heads, a plurality of needle bars supporting needles and thread take up levers are provided. Each bed contains a rotary hook drive motor provided independent of a sewing machine motor which drives a spindle extending through the heads. The rotary hook drive motor is driven in synchronization with the spindle for performing embroidery stitching, but is driven independently of the spindle at a specific rotation angle range thereof based on number of stitching. In each bed, a conventional needle thread holding mechanism is dispensed with. By controlling rotation of the rotary hook drive motor, a residual end part of the needle thread has a sufficient length capable of avoiding disengagement of the residual end part from an eyelet of the needle at a thread cutting operation.

Abstract: A shuttle hook driving device for driving a shuttle hook having a beak disposed between a needle drop position and a bobbin thread lead-out point of a bobbin in a sewing machine which includes a main shaft, a needle bar, a thread take-up lever, and a conversion mechanism for converting a rotation of the main shaft into an oscillating motion, the shuttle hook driving device comprises: a counter balance connected to the needle bar and the thread take-up lever, the counter balance being mounted on the main shaft such that the counter balance is displaced a predetermined angle with respect to the main shaft as compared with a standard sewing machine; an output shaft received the oscillating motion from the conversion mechanism, the output shaft being connected to the conversion device in right-left inverted relation with respect to an axis thereof as compared with the standard sewing machine, using an uppermost point of the needle bar as a reference; and a driver connected to the output shaft, for driving the shu

Abstract: In a zig-zag sewing machine wherein a sewing needle is shifted laterally with respect to a hook rotated about a fixed axis, the hook is optimally timed with respect to the needle at each shifted stitch position of the needle by accelerating rotation of the hook to advance it into optimal disposition relative to the needle at one stitch position of the needle and decelerating rotation of the hook to retard it into equally optimal disposition relative to the needle at the other stitch position of the needle.

Abstract: A sewing machine needle has a chamfer portion formed in its shaft which defines an interspace between the needle shaft and a thread running in an upward direction parallel to the needle shaft to permit a thread loop catching device to enter into the interspace during machine operation. The chamfer portion is formed by a portion of the needle shaft which is displaced with respect to the axis of the needle which extends substantially parallel thereto and yet which has substantially the same transverse cross-section as other portions of the shaft and by shaft transition portions which adjoin the displaced shaft portion which extend at an angle with respect to the needle axis. In this manner, a deep chamfer portion is obtained so as to increase the interspace between the needle shaft and sewing thread so that a reliable engagement of the sewing thread by the thread loop catching device can be achieved without the necessity of a so-called loop stroke.

Abstract: This disclosure relates to hook drive mechanisms for sewing machines and in particular to a hook drive mechanism wherein the hook member is freely supported by a bearing means in a hook support plate carried by the bed portion of the frame and is driven by a likewise freely supported drive member. The support plate with the hook member is supported for relative adjustment with the needle for adjusting the hook point-to-needle relationship. The hook member is readily removable in that it is freely supported in the aforementioned bearing means and is otherwise only restrained by a movable restraining means carried by a hook member cover plate which when removed from restraining relationship permits the bobbin and the hook member to be easily lifted out from the machine. Further, means are carried on the hook support plate for adjusting and maintaining tension on a timing belt drive means for the hook mechanism.

Abstract: A sewing machine loop taker support bracket that is adjustable to permit the use of various size loop takers. The loop taker shaft is journalled in one end of the support bracket and is coupled by a timing belt to a lateral stud shaft journalled in the opposite end of the bracket, the stud shaft being driven through bevel gears by the machine bed shaft. Various size loop takers are accommodated by loosening the support bracket from the machine frame and adjusting the bracket about the stud shaft axis until the loop taker is properly positioned.