Patent ID: 8561716

Claim:
A power tool comprising: a housing, a motor housed in the housing, an internal mechanism driven by the motor, the internal mechanism including a motion converting mechanism and a power transmitting mechanism, an internal mechanism chamber provided formed within the housing to house at least a part of the internal mechanism, a tool bit disposed in one end of the housing and driven by the internal mechanism in the longitudinal direction of the tool bit to perform a predetermined operation, a handgrip connected to the other end of the housing, and a dynamic vibration reducer including a weight and an elastic element, the elastic element being adapted to apply a biasing force to the weight, wherein the weight reciprocates in the longitudinal direction of the tool bit against the biasing force of the elastic element, whereby the dynamic vibration reducer reduces vibration which is caused in the housing in the longitudinal direction of the tool bit in the working operation, and wherein the dynamic vibration reducer including the weight and the elastic member is located in a hermetic space within the internal mechanism chamber, wherein: the elastic element includes a first spring and a second spring, the first spring being mounted on one single side of the weight in the forward and rearward directions, the second spring being mounted on another single side of the weight in the forward and rearward directions; and each of the first spring and second spring includes two separate springs flanking the corresponding single side of the weight.