Zigzag sewing machine

Abstract

A zigzag sewing machine includes a frame, a needle bar supporting member mounted on the frame for swinging motion about a horizontal fixed axis, and a needle bar carried by the needle bar supporting member for endwise reciprocation. A rotary member is rotatably supported by the frame for rotary motion about an axis parallel to the horizontal fixed axis, and a connecting rod is connected eccentrically and pivotally at the upper end thereof to one side of the rotary member. The connecting rod is connected pivotally at the lower end thereof to the needle bar at a position below the upper end. At a moment when the shuttle hook of a shuttle catches a loop, the upper end of the connecting rod and the shuttle hook of the shuttle move in a direction opposite to the direction of swinging motion of the needle bar supporting member. When the shuttle hook catches a loop, the lower end of the connecting rod is located above the horizontal fixed axis about which the needle bar supporting member swings. Accordingly, when the shuttle hook catches a loop with the needle located at the opposite ends of its lateral swinging motion range, the needle is located at substantially the same height.