Patent ID: 7591326
Filing Date: 2009-09-22
Classification: B23B,B25B,B25D,F16D

Abstract:
1. A power tool, comprising: a tool bit that performs a predetermined operation by rotating around its longitudinal axis, a driving mechanism that drives the tool bit, and a torque limiter engaged with the driving mechanism that transmits a torque of the driving mechanism to the tool bit when a torque acting upon the tool bit is lower than a predetermined set value, while interrupting the torque transmission of the driving mechanism when the torque acting upon the tool bit exceeds the set value, wherein the torque limiter comprises: an elastic member that applies a biasing force in the axial direction of the first rotating member with respect to the ball via the pressing member, a power transmission interrupted region comprising a groove that is continuously formed in the circumferential direction in a depth shallower than or equal to the shallowest groove part of the power transmitting region to interrupt the torque transmission between the first and second rotating members by release of the engagement with the ball in the circumferential direction, wherein, when the ball is in the power transmitting region, the pressing member contacts the first rotating member such that the biasing force of the elastic member is prevented from acting upon the ball, while, when the ball is moved from the power transmitting region to the power transmission interrupted region, the pressing member is pushed by the ball in the axial direction and applies the biasing force of the elastic member to the ball.