Patent ID: 8944180
Filing Date: 2015-02-03
Classification: B25B,B25F

Abstract:
1. A power tool which performs a predetermined operation on a workpiece by driving a tool bit comprising: a prime mover that drives the tool bit, and a power transmitting mechanism that transmits torque of the prime mover to the tool bit, wherein: the power transmitting mechanism has a driving-side member which is rotationally driven by the prime mover, and a driven-side member to which the tool bit is coupled, and when the tool bit is not pressed against the workpiece, the power transmitting mechanism is held in a power transmission interrupted state in which torque of the driving-side member is not transmitted to the driven-side member, and when the tool bit is pressed against the workpiece, the power transmitting mechanism is held in a power transmission state in which the tool bit moves together with the driven-side member in an axial direction of the tool bit so that the driven-side member receives the torque from the driving-side member and the tool bit is driven, and a tapered portion is provided between the driving-side member and the driven-side member and inclined with respect to the axial direction of the tool bit, and when the driven-side member moves in the axial direction of the tool bit, frictional force is caused on the tapered portion and the torque of the driving-side member is transmitted to the driven-side member by the frictional force, wherein an intervening member is provided between the driving-side member and the driven-side member and can be engaged with the both members, and the torque of the driving-side member is transmitted to the driven-side member via the intervening member by frictional contact of the intervening member with the tapered portion.