Abstract: For the continuous drive of a hook of a sewing machine, two drive cams (17) alternately engage in the back of the hook. During the passing of the upper thread loop, the respective drive cam (17) on which the thread would get hung up is out of engagement. The hook is situated in a conical hook race guide and is held therein by magnets.

Abstract: A bobbin detachably installed into an inner hook of a sewing machine is disclosed. The bobbin includes a bobbin shaft; and a pair of flanges that are provided at both axial ends of the bobbin shaft. The bobbin shaft is cylindrical and includes a first opening and a second opening defined on axial ends thereof, the bobbin shaft being provided with a restriction member in a proximity of either of the first and the second opening to allow attachment of the bobbin to the inner hook through the first opening.

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.