A portable power tool of an impulse type.

摘要

A rotary power tool is operated by an air motor or electric motor drive designed to produce an adjustable output torque. The driven impulse member (40) has a cam surface (64) driven by a driver (66) which is axially or radially movable in a driving cage (32) mechanism whereby the torque developed by the power tool cyclically varies betweeen zero and a predetermined adjustable maximum quantity. Due to the cyclical variation in the torque developed there is no impact component of the torque delivered and therefore the tightening torque will not increase as the number of torque cycles increases.