Patent ID: 7059425
Filing Date: 2006-06-13
Classification: B25D

Abstract:
1. A reciprocating power tool comprising: a tool bit that performs a predetermined operation on a workpiece by a reciprocating movement; a driving motor that drives the tool bit; a power transmission mechanism including an internal gear that is prevented from rotating under normal operation, wherein the power transmission mechanism converts a rotating output of the driving motor into linear motion in the axial direction of the tool bit; a planetary gear that engages the internal gear; a power transmission pin that is eccentrically disposed on the planetary gear, wherein the internal gear is allowed to rotate by a predetermined degree in relation to a load applied to the tool bit, and an internal gear rotation control device having a first gear engaging portion and a second gear engaging portion, wherein the first gear engaging portion engages a first notch of the internal gear when a load is applied to the tool bit to prevent rotation of the internal gear, and the first gear engaging portion disengages from the notch when no load is applied to the tool bit to allow the internal gear to rotate until the second gear engaging portion engages a second notch of the internal gear to prevent rotation of the internal gear, and whereby the relative position of the power transmission pin is changed with respect to the point of engagement between the internal gear and the planetary gear, so that a linear stroke of the power transmission pin in the axial direction of the tool bit is changed.