Overlock sewing machine having looping width adjusting mechanism

摘要

An overlock sewing machine having a dial and a conversion means for converting the rotary motion of the dial into a linear motion which are associated with a cutter blade holder such that the adjustment of the distance between a stationary claw and a movable claw adjusts the looping width in correspondence with the linear movement of the cutter blade holder perpendicular to the direction of feed of the cloth caused by rotation of the dial. The movable claw, carried by a movable member, can move between an operative position in which the movable claw is positioned next to the side of the stationary claw and an inoperative position spaced away from the side of the stationary claw. The position at which the cutter blade holder is supported on the machine body is offset from the position at which the upper and lower cutting blades make contact. A spring-like resilient member is disposed between the throat plate or the machine body and the cutter blade holder or the lower cutter blade so as to upwardly or downwardly bias the cutter blade holder. An extension on either the stationary or movable claw is adapted to lap over the other claw to prevent the cloth from dropping into the gap between the two claws preventing any disorder in the seam.