ANNULAR THREAD CUTTING DIE HEAD FOR THREAD CUTTING MACHINE AND THREAD CUTTING DEVICE

摘要

An annular thread cutting die head for a power driven threading machine is comprised of an annular support plate supporting a plurality of radially displacable thread cutting dies spaced apart about the axis of the die head, and an annular cam plate assembly coaxial with and pivotal relative to the support plate to radially displace the cutting dies. The cam plate assembly is spring biased to pivot relative to the support plate in the direction to radially retract the cutting dies, and is selectively operable relative to the support plate to achieve the cutting of a straight thread or to achieve the cutting of a tapered thread. In connection with the cutting of a tapered thread, receding replacement of the cutting tools is controlled by a unique cam arrangement on the machine carriage engaged by the cam plate assembly under the spring bias and independent of torque imposed on the die head during the threading operation.