It is an object of the invention to provide an effective technique for
improving the durability of a torque limiter utilized in a power tool.
The object is achieved by a representative power tool comprising a tool
bit, a driving mechanism and a torque limiter. The torque limiter
includes first and second rotating members, a ball, a pressing member and
an elastic member. The second rotating member includes a power
transmitting region with a groove continuously formed from a deepest
groove part to a shallowest groove part to allow torque transmission and
a power transmission interrupted region with a groove shallower than the
shallowest groove part of the power transmitting region to interrupts the
torque transmission. According to this construction, when the ball is in
the power transmitting region, the pressing member contacts the first
rotating member and is held in a position in which the biasing force of
the elastic member is prevented from acting upon the ball.