US Patent 7168503 Power hand tool

A power hand tool includes a housing that houses a motor, a transmission gear set, a torque control mechanism and an impact mechanism. The torque control mechanism has an adjustment device that is movable between a first position and a second position inside the housing by a rotation action to set a predetermined output torque of the power hand tool. The output torque of the power hand tool is at the minimum condition and the adjustment device stops the impact mechanism from working to prevent destruction to the torque setting of the power hand tool when the adjustment device is in the second position.