초록 ▼

It is an object of the invention to provide an improved technique for lessening an impact force caused by rebound of a tool bit after the striking movement of the tool bit. Representative impact power tool (101) includes a tool body (103), a hammer actuating member (119, 145), a driving mechanism (1

It is an object of the invention to provide an improved technique for lessening an impact force caused by rebound of a tool bit after the striking movement of the tool bit. Representative impact power tool (101) includes a tool body (103), a hammer actuating member (119, 145), a driving mechanism (113, 115), a weight (163) and an elastic element (165). A reaction force that the hammer actuating member receives from the workpiece when performing a hammering operation is transmitted from the hammer actuating member to the weight (163) and then, the weight (163) is caused to move rearward to push the elastic element (165). As a result, the reaction force can be absorbed by the elastic element (165). The elastic force of the elastic element (165) is prevented from acting upon the weight (163) forward beyond the reaction force transmitting position.

대표청구항 ▼

I claim: 1. An impact power tool comprising: a tool body, a hammer actuating member disposed in a tip end region of the tool body to perform a predetermined hammering operation on a workpiece by reciprocating movement in an axial direction of the hammer actuating member, an air spring, a driving me

I claim: 1. An impact power tool comprising: a tool body, a hammer actuating member disposed in a tip end region of the tool body to perform a predetermined hammering operation on a workpiece by reciprocating movement in an axial direction of the hammer actuating member, an air spring, a driving mechanism that linearly drives the hammer actuating member by means of the air spring, a weight located in a reaction force transmitting position, the reaction force transmitting position being defined by a state in which the weight is placed in direct contact with the hammer actuating member or the weight is placed in contact with the hammer actuating member via direct contact with an intervening member made of hard metal, wherein a reaction force that the hammer actuating member receives from the workpiece when performing a hammering operation is transmitted from the hammer actuating member to the weight, when the weight is located in the reaction force transmitting position, an elastic element that is elastically deformed when the reaction force transmitted to the weight causes the weight to move rearward from the reaction force transmitting position and directly contact the elastic element, wherein the elastic element absorbs the reaction force and a control member that prevents an elastic force of the elastic element from displacing the weight forward beyond the reaction force transmitting position. 2. The impact power tool as defined in claim 1, further comprising an elastic member, aside from the elastic element, wherein the elastic member is disposed between the hammer actuating member and a striking mechanism that includes a cylinder fixedly mounted to a gear housing that contacts the tool body and wherein, during hammering operation, a pushing force acts upon the hammer actuating member when the hammer actuating member is pressed against the workpiece causing the hammer actuating member to move rearward and contact the elastic member such that the elastic member elastically connects the hammer actuating member to the tool body, thereby positioning the tool body with respect to the workpiece. 3. The impact power tool as defined in claim 2, wherein the weight and the elastic member are disposed along substantially parallel longitudinal axes of the hammer actuating member. 4. The impact power tool as defined in claim 2, wherein the hammer actuating member contacts the weight and the elastic member via the intervening member made of hard metal, the intervening member being disposed between the hammer actuating member and the weight and between the hammer actuating member and the elastic member. 5. The impact power tool as defined claim 2, wherein the hammer actuating member includes an impact bolt that receives a driving force of the driving mechanism, and a tool bit that is caused to reciprocate by collision with the impact bolt, and wherein the tool bit transmits the reaction force from the workpiece to the weight in the state of contact with the weight. 6. The impact power tool as defined in claim 1, wherein the control member comprises a stopper that contacts the weight to prevent the weight from moving forward beyond the reaction force transmitting position. 7. The impact power tool as defined in claim 1, wherein the hammer actuating member includes an impact bolt that receives a driving force of the driving mechanism, and a tool bit that is caused to reciprocate by collision with the impact bolt, and wherein the impact bolt transmits the reaction force from the workpiece to the weight in a state of contact with the weight. 8. The impact power tool as defined in claim 1 further comprising a vibration reducing weight, aside from said weight, wherein the vibration reducing weight is connected to the tool body to reduce vibration by reciprocating in the same direction as the hammer actuating member. 9. The impact power tool as defined in claim 1 further comprising: an air spring actuation member switched between a non-actuating position in which the air spring is disabled to operate and an actuating position in which the air spring is enabled to operate and a biasing member that biases the air spring actuation member to be placed in the non-actuating position. 10. The impact power tool as defined in claim 9, wherein, when the hammer actuating member is pressed against the workpiece during hammering operation, the hammer actuating member is pushed rearward by the workpiece and directly pushes the air spring actuation member from the non-actuating position to the actuating position. 11. The impact power tool as defined in claim 1, wherein the intervening member is mounted between the hammer actuating member and the weight such that the intervening member does not move in an axial direction of the hammer actuating member with respect to the tool body when the hammer actuating member moves from an unloaded state to a loaded state.