Abstract: A power tool for performing a predetermined operation by using a tool driven by a motor including a first housing to which the tool is attached at an end of the first housing and which has a cylindrical portion of the first housing, a second housing which has a cylindrical portion of the second housing covering the cylindrical portion of the first housing, and a vibration reduction member which is provided between the cylindrical portion of the first housing and the cylindrical portion of the second housing and which reduces transmission of vibration between the first housing and the second housing via elastic shearing deformation of the vibration reduction member. A direction of the shearing deformation of the vibration reduction member corresponds to a direction of a rotation axis of the motor.

Abstract: A hammer drill includes, in a cylinder accommodated in a housing, a piston configured to advance and retract and an impact element to operate together with the piston with an air chamber interposed therebetween, and a bit mounted in a front part of a tool main body so that an impact operation can be transmitted to the bit by advancing and retracting movement of the impact element. Vent holes are provided in the cylinder, and configured to discharge air in the air chamber to outside of the cylinder, and to introduce the air outside the cylinder into the air chamber by the movement of the piston. One of the vent holes is located at a center of an upper half of a periphery of the cylinder and the other vent hole is located in a lower half of the periphery of the cylinder.

Abstract: An impact tool includes a reaction force transmitting member, a first elastic member that biases the transmitting member forward, and a second elastic member that is pushed by the transmitting member and compressively deforms when the transmitting member moves rearward by receiving a striking reaction force caused when a tool bit strikes a workpiece, thereby cushioning the force. When the tool bit is pressed against the workpiece, the transmitting member is pushed by the tool bit and compresses the first elastic member, and comes in contact with the second elastic member in an uncompressed state, so that the transmitting member is placed in a predetermined working position in the longitudinal direction. When the transmitting member receives the striking reaction force in the working position, the transmitting member moves rearward in the axial direction of the tool bit and compressively deforms the second elastic member, thereby cushioning the striking reaction force.

Abstract: A representative power tool according to the invention performs a predetermined operation on a workpiece at least by axial linear movement of a tool bit 119 coupled to a front end region of a housing 103. The power tool includes driving mechanisms 113, 115 that are housed within the housing 103 and linearly drives the tool bit 119, and a dynamic vibration reducer 151 that has a weight 153 which is allowed to linearly move under a biasing force of an elastic element, and reduces vibration caused during operation, by movement of the weight 153 in the axial direction of the tool bit. A dynamic vibration reducer housing space 149 for housing the weight 153 and the elastic element of the dynamic vibration reducer 151 is integrally formed with the housing 103.

Abstract: It is an object of the invention to provide a technique that contributes to rationalization of a mechanism relating to reduction of vibration in an impact tool. Representative impact tool includes a tool body, a hammer actuating member, a dynamic vibration reducer and a positioning elastic element. The positioning elastic element contacts the hammer actuating member and thereby positions the tool body with respect to the workpiece so as to absorb a reaction force caused by rebound from the workpiece and acts on the hammer actuating member when the hammer actuating member performs the hammering operation on the workpiece. The positioning elastic element includes the elastic element formed as a component part of the dynamic vibration reducer.

Abstract: A hammer drill includes, in a cylinder accommodated in a housing, a piston configured to advance and retract and an impact element to operate together with the piston with an air chamber interposed therebetween, and a bit mounted in a front part of a tool main body so that an impact operation can be transmitted to the bit by advancing and retracting movement of the impact element. Vent holes are provided in the cylinder, and configured to discharge air in the air chamber to outside of the cylinder, and to introduce the air outside the cylinder into the air chamber by the movement of the piston. One of the vent holes is located at a center of an upper half of a periphery of the cylinder and the other vent hole is located in a lower half of the periphery of the cylinder.

Abstract: Improving vibration reduction of a handle in a hand-held power tool by performing a predetermined operation on a workpiece by linear movement of a tool bit in an axial direction. The power tool includes a power tool body, a handle and a vibration-proofing part. The vibration-proofing part includes an elastic element that is disposed between the power tool body and the handle and reduces transmission of vibration from the power tool body to the handle, and also includes a body-side receiving part and a handle-side receiving part which are opposed to each other so as to hold the elastic element. The vibration-proofing part is designed such that deformation of the elastic element is shearing deformation in each of the direction of a z-axis defined along the axial direction of the tool bit and the directions of a y-axis and an x-axis which intersect with the z-axis.

Abstract: A power tool for performing a predetermined operation by using a tool driven by a motor including a first housing to which the tool is attached at an end of the first housing and which has a cylindrical portion of the first housing, a second housing which has a cylindrical portion of the second housing covering the cylindrical portion of the first housing, and a vibration reduction member which is provided between the cylindrical portion of the first housing and the cylindrical portion of the second housing and which reduces transmission of vibration between the first housing and the second housing via elastic shearing deformation of the vibration reduction member. A direction of the shearing deformation of the vibration reduction member corresponds to a direction of a rotation axis of the motor.

Abstract: A representative power tool according to the invention performs a predetermined operation on a workpiece at least by axial linear movement of a tool bit 119 coupled to a front end region of a housing 103. The power tool includes driving mechanisms 113, 115 that are housed within the housing 103 and linearly drives the tool bit 119, and a dynamic vibration reducer 151 that has a weight 153 which is allowed to linearly move under a biasing force of an elastic element, and reduces vibration caused during operation, by movement of the weight 153 in the axial direction of the tool bit. A dynamic vibration reducer housing space 149 for housing the weight 153 and the elastic element of the dynamic vibration reducer 151 is integrally formed with the housing 103.

Abstract: Representative impact tool according to the invention includes a reaction force transmitting member 161 that receives a striking reaction force caused when a tool bit 119 strikes a workpiece, a first elastic member 163 that biases the reaction force transmitting member 161 forward, and a second elastic member 171 that is pushed by the reaction force transmitting member 161 and compressively deforms, thereby cushioning the striking reaction force, when the reaction force transmitting member 161 moves rearward by receiving the striking reaction force.

Abstract: Improving vibration reduction of a handle in a hand-held power tool by performing a predetermined operation on a workpiece by linear movement of a tool bit in an axial direction. The power tool includes a power tool body, a handle and a vibration-proofing part. The vibration-proofing part includes an elastic element that is disposed between the power tool body and the handle and reduces transmission of vibration from the power tool body to the handle, and also includes a body-side receiving part and a handle-side receiving part which are opposed to each other so as to hold the elastic element. The vibration-proofing part is designed such that deformation of the elastic element is shearing deformation in each of the direction of a z-axis defined along the axial direction of the tool bit and the directions of a y-axis and an x-axis which intersect with the z-axis.

Abstract: It is an object of the invention to improve vibration reduction of an auxiliary handle for a hand-held power tool. According to the invention, a representative elongate auxiliary handle 121 to be mounted to a tool body 103 of a power tool 101 includes a handle body 123 that is fixedly mounted to the tool body 103 and an elongate grip 125. The grip 125 has a grip region on its outer surface to be held by a user, and the grip 125 is mounted to the handle body 123 via elastic elements 133 in between a middle region of the grip region in its longitudinal direction and an end of the grip which is remote from the tool body 103.

Abstract: It is an object of the invention to provide a technique for further improving the vibration reducing performance in a power impact tool that linearly drives a tool bit by using a swinging mechanism. According to the invention, a representative power impact tool is provided with a motor, a rotating shaft, a swinging member, a tool driving mechanism and a counter weight. The swinging member is supported by the rotating shaft to swing in the axial direction of the rotating shaft by rotation of the rotating shaft. The counter weight is disposed in a region higher than a lower end region of the swinging member in the vertical direction to intersect with the axis of the rotating shaft, and a lower end of the counter weight is connected to the lower end region of the swinging member.

Abstract: It is an object of the invention to provide a technique that contributes to rationalization of a mechanism relating to reduction of vibration in an impact tool. Representative impact tool includes a tool body, a hammer actuating member, a dynamic vibration reducer and a positioning elastic element. The positioning elastic element contacts the hammer actuating member and thereby positions the tool body with respect to the workpiece so as to absorb a reaction force caused by rebound from the workpiece and acts on the hammer actuating member when the hammer actuating member performs the hammering operation on the workpiece. The positioning elastic element includes the elastic element formed as a component part of the dynamic vibration reducer.

Abstract: It is an object of the invention to provide a technique for further improving the vibration reducing performance in a power impact tool that linearly drives a tool bit by using a swinging mechanism. According to the invention, a representative power impact tool is provided with a motor, a rotating shaft, a swinging member, a tool driving mechanism and a counter weight. The swinging member is supported by the rotating shaft to swing in the axial direction of the rotating shaft by rotation of the rotating shaft. The counter weight is disposed in a region higher than a lower end region of the swinging member in the vertical direction to intersect with the axis of the rotating shaft, and a lower end of the counter weight is connected to the lower end region of the swinging member.