Abstract: It is an object of the present invention to provide a reciprocating power tool having a further improved power transmission mechanism for converting a rotating output of a driving motor into linear motion in the axial direction of the tool bit. According to the present invention, a representative reciprocating power tool may comprise a tool bit, a driving motor, a power transmission mechanism. The power transmission mechanism converts a rotating output of the driving motor into linear motion in the axial direction of the tool bit. The power transmission mechanism includes an internal gear, a planetary gear and a power transmission pin. The internal gear is allowed to rotate by a predetermined degree in relation to a load applied to the tool bit. As the result of rotation of the internal gear, 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.

Abstract: It is an object of the invention to provide a reciprocating power tool having a further improved power transmitting mechanism for converting a rotating output of a driving motor into linear motion in the axial direction of the tool bit. The representative reciprocating power tool may comprise a tool bit, a driving motor and a power transmitting mechanism that converts a rotating output of the driving motor into linear motion in the axial direction of the tool bit. The power transmitting mechanism includes an internal gear, a planerary gear, a power transmitting part, a rotation preventing mechanism and an internal gear rotation lock. Further, an internal gear rotation lock prevents the internal gear from rotating in a direction opposite to said predetermined direction. Therefore, the internal gear rotated only in one direction via the internal gear rotation lock and as a result, the internal gear can be reliably locked in a predetermined position without causing rattling.

Abstract: It is, accordingly, an object of the present invention to provide an electric hammer with improved construction, while ensuring the vibration reduction performance. According to the present invention, a representative electric hammer may include a hammer bit, a driving motor, a crank mechanism and a counter weight. The crank mechanism drives a striker by converting a rotating output of the driving motor to linear motion in the axial direction of the hammer bit. The counter weight is detachably mounted to the crank mechanism and serves to reduce vibration of the striker. According to the representative hammer, because the counter weight is detachably mounted to the crank mechanism, it is possible to switch between the mode in which the counter weight is mounted on the hammer body in order to reduce and alleviate vibration and the mode in which the counter weight is removed from the hammer so that the operation can be performed with the hammer having a lighter weight and slimmer appearance.

Abstract: It is an object of the invention to provide a technique for further improving the vibration reducing performance in the power tool, while avoiding complicating the construction of the power tool. According to the present invention, a representative power tool may comprise a striker, a tool bit and a vibration reducer. The vibration reducer serves to reduce vibration on the striker by reciprocating in a direction opposite to the reciprocating direction of the striker. The path of the center of gravity of the vibration reducer is arranged to coincide with a path of the center of gravity of the striker. With such construction, because rotating moment is not exerted onto the reciprocating cylinder during the operation of the power tool, vibration reduction can be performed in a stable manner.

Abstract: It is, accordingly, an object of the present invention to provide an electric hammer with improved construction, while ensuring the vibration reduction performance. According to the present invention, a representative electric hammer may include a hammer bit, a driving motor, a crank mechanism and a counter weight. The crank mechanism drives a striker by converting a rotating output of the driving motor to linear motion in the axial direction of the hammer bit. The counter weight is detachably mounted to the crank mechanism and serves to reduce vibration of the striker. According to the representative hammer, because the counter weight is detachably mounted to the crank mechanism, it is possible to switch between the mode in which the counter weight is mounted on the hammer body in order to reduce and alleviate vibration and the mode in which the counter weight is removed from the hammer so that the operation can be performed with the hammer having a lighter weight and slimmer appearance.

Abstract: It is an object of the present invention to provide a reciprocating power tool having a further improved power transmission mechanism for converting a rotating output of a driving motor into linear motion in the axial direction of the tool bit. According to the present invention, a representative reciprocating power tool may comprise a tool bit, a driving motor, a power transmission mechanism. The power transmission mechanism converts a rotating output of the driving motor into linear motion in the axial direction of the tool bit. The power transmission mechanism includes an internal gear, a planetary gear and a power transmission pin. The internal gear is allowed to rotate by a predetermined degree in relation to a load applied to the tool bit. As the result of rotation of the internal gear, 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.