Hook timing arrangement for zig zag sewing machines

In a sewing machine of the type adapted for forming stitches in a zig-zag pattern, said sewing machine having a thread-carrying needle, needle manipulating means for reciprocating said needle longitudinally to form thread loops and for shifting said needle laterally between spaced first and second loop-forming positions to distribute the thread loops in a zig-zag pattern, a looptaker rotatable about a fixed axis and having a hook for cooperating with said needle to seize the thread loops, and means for rotating said looptaker, the improvement comprising means coupling said looptaker rotating means to said needle manipulating means for alternately accelerating and decelerating rotation of said looptaker in timed relation to lateral shifting movement of said needle between its first and second loop-forming positions to advance said hook of said looptaker into a first loop-seizing disposition in relation to said needle at its said first loop-forming position and to retard said hook of said looptaker into a second loop-seizing disposition in relation to said needle at its said second loop-forming position.