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 double-lock-stitch sewing machine has a reciprocating needle forming an upper-thread loop with the aid of a rotary gripper assembly. The loop is carried by and formed by a main hook or point of the assembly around a stationary bobbin to engage a bobbin thread in a double-lock-stitch. A counter hook or counter point on the gripper assembly, which normally serves only to control movement of the loop from the main point, is formed on an underside with an auxiliary hook portion for drawing an extra thread length from the supply during each stitch and thus inhibiting bunching of the workpiece.