Patent ID: 7712546
Filing Date: 2010-05-11
Classification: B25B,B25F,Y10T

Abstract:
1. A rotary fastening tool comprising: a tool body, a motor housed within the tool body, a driving-side rotating member that is rotationally driven by the motor, a driven-side rotating member that is disposed coaxially with the driving-side rotating member, a tip-end side rotating member that is disposed coaxially with the driven-side rotating member and rotationally driven via the driven-side rotating member, the tip-end side rotating member driving a tool bit to perform a tightening operation and a rotation control mechanism that allows the tip-end side rotating member to rotate in the tightening direction during the tightening operation of the tool bit, wherein, when the tip-end side rotating member is fixed to a workpiece with the tool bit during the tightening operation and when torque transmission from the driving-side rotating member to the driven-side rotating member is interrupted, the rotation control mechanism locks the tip-end side rotating member and the tool body together against rotation with respect to each other to prevent the tool body from rotating in the tightening direction, wherein, during a loosening operation of the tool bit, the rotation control mechanism is disabled from locking the tip-end side rotating member and the tool body by utilizing a rotation of the driven-side rotating member in the loosening direction to allow the loosening operation of the tool bit.