Abstract: It is an object of the invention to provide a power tool with a rational placement of a dynamic vibration reducer within a tool body. A representative hammer drill embodied as a power tool according to this invention has a dynamic vibration reducer 151 which is placed within an internal space 110 located to a motion converting section 113 side of a driving motor 111 within a body 103. An inner edge of the internal space is defined by an outer edge of the motion converting section 113, and an outer edge of the internal space is defined by an outer periphery of the driving motor 111.

Abstract: The impacting tool has a tool holder and a locking part. The locking part can be driven to move between the bit holding position, where it is engaged with the tool bit inserted into the bit inserting hole so that pullout is restrained, and a bit holding released position where the engagement is released and pullout is allowed. The locking part and the tool holder can be integrated with each other while moving in the longitudinal direction of the tool bit, so that they can be driven to move between the bit anchored position where the locking part is set at the bit holding position and the engagement state with respect to the tool bit is maintained, and the bit last connection/disconnection allowed position where the locking part is set at the bit holding released position and releasing of the engagement with respect to the hammer bit is allowed.

Abstract: An electric tool causes a drive mechanism to drive a tip tool to thereby cause the tip tool to perform predetermined work, and the drive mechanism is provided with a driving gear and a driven gear which meshes with the driving gear. The electric tool is configured in such a manner that an axial force or a radial force generated by the meshing between the driving gear and the driven gear is measured to detect the state of torque acting on the tip tool, and drive control of the drive mechanism is performed according to the detected state of torque.

Abstract: Disclosed is a striking tool technology that contributes to reducing clutch sizes. The striking tool causes a tool bit to perform a striking operation in the long axis direction and to perform a rotational operation about the long axis, thereby causing the tool bit to carry out a predetermined machining operation. The striking tool comprises a tool body; a motor which is housed in the tool body and drives the tool bit; and a clutch which, on a route where the torque of the motor is transmitted to the tool bit, is disposed in a high rotational speed and low torque region that is a stage prior to where the rotational speed of the motor is reduced, which transmits the torque of the motor to the tool bit in a normal state, and which cuts off the transmission of torque generated about the tool bit long axis in the tool body if the torque exceeds a predetermined torque level.

Abstract: A power tool capable of performing vibration damping action in working operation, without an increase in size. The working tool includes a motor, a housing in which an internal mechanism driven by the motor is stored, a tool bit disposed on one end of the housing, a hand grip continuously connected to the other end of the housing, and a dynamic damper. The dynamic damper is disposed by utilizing a space between the housing and the internal mechanism so that the damping direction of the dynamic damper faces the longitudinal direction of the tool bit.

Abstract: Provided is a power tool which is capable of more reliably detecting excessive reaction torque acting on a tool body. More specifically, provided is a handheld power tool which causes a tip tool to rotate so as to carry out a predetermined machining operation, the handheld power tool comprising a tool body, a motor which is housed in the tool body and causes the tip tool to rotate, a first sensor which detects the torque state of the tip tool, a second sensor which detects the motion state of the tool body, and a torque cut-off mechanism which cuts off the transmission of torque between the motor and the tip tool. The torque cut-off mechanism is configured to cut off the transmission of torque on the condition that the first sensor and the second sensor respectively detect a preset threshold value for the first sensor and the second sensor.

Abstract: A striking tool comprises a tool body; a motor housed in the tool body; striking action drive mechanisms which are driven by the motor and strike a tool bit; a rotational drive mechanism which is driven by the motor and causes the tool bit to rotate; an operating mode switching member which switches between a first operating mode wherein the tool bit performs the striking operation and a second operating mode wherein the tool bit performs rotational operation at a minimum; and a clutch which transmits and cuts off torque between the motor and the rotational drive mechanism. The striking tool is capable of switching between operation modes while preventing excessive reaction torque from acting on the tool body.

Abstract: An electric hammer comprising a hammer bit performing hammering work on a work, a drive motor, a hammering piece driven by the drive motor to apply a hammering force to the hammer bit, and a mechanism for damping vibration generated during hammering. The damping performance of the electric hammer is enhanced by causing the driving amount applied to the damping mechanism to vary between a first mode where the damping mechanism generates vibration of the hammer bit subjected to an external force from the work during the load driving time and thereby optimizes the damping and a second mode where the damping mechanism generates vibration corresponding to the vibration of the hammer bit not subjected to an external force from the work during the no-land driving time and optimizes damping.

Abstract: A power tool capable of performing vibration damping action in working operation, without an increase in size. The working tool includes a motor, a housing in which an internal mechanism driven by the motor is stored, a tool bit disposed on one end of the housing, a hand grip continuously connected to the other end of the housing, and a dynamic damper. The dynamic damper is disposed by utilizing a space between the housing and the internal mechanism so that the damping direction of the dynamic damper faces the longitudinal direction of the tool bit.

Abstract: It is an object of the invention to provide a technique for reducing vibration by counter weights which smoothly operate without linearly reciprocating, in a reciprocating power tool. The reciprocating power tool has first and second bevel gears 123, 147 which are opposed to each other on either side of a pinion 119 and rotationally driven in opposite directions at the same reduction ratio by the pinion 119. Further, the reciprocating power tool has a slider 107 which is caused to linearly reciprocate in a longitudinal direction of a tool bit 111 by a crank 129. The first and second bevel gears 123, 147 are provided with first and second counter weights 143, 145 in positions displaced from their rotation axes, respectively.

Abstract: A hand-held power tool has a tool body, a motor housed in the tool body and a grip part designed to be held by a user, and performs a predetermined operation on a workpiece by a tool bit rotationally driven by the motor. The power tool includes a clutch that transmits torque and interrupts torque transmission between the motor and the tool bit, a non-contact torque sensor that detects torque acting on the tool bit in non-contact with a rotation axis rotating together with the tool bit, and a clutch control system that controls coupling and decoupling of the clutch according to a torque value detected by the non-contact torque sensor.

Abstract: A power tool capable of performing vibration damping action in working operation, without an increase in size. The working tool includes a motor, a housing in which an internal mechanism driven by the motor is stored, a tool bit disposed on one end of the housing, a hand grip continuously connected to the other end of the housing, and a dynamic damper. The dynamic damper is disposed by utilizing a space between the housing and the internal mechanism so that the damping direction of the dynamic damper faces the longitudinal direction of the tool bit.

Abstract: A hammer drill equipped with a main body part; a drive motor; a motion conversion mechanism, and a vibration absorber which are housed in the main body part; and a handgrip which is provided as a continuation of the main body part at a position closer to the rear end side of the tool than the drive motor and used for gripping the tool. The absorber is in a configuration where vibrations of the main body part are suppressed during a machining operation.

Abstract: It is an object of the invention to provide a rational forced vibration of a dynamic vibration reducer in an impact tool that linearly drives a tool bit in an axial direction of the tool bit via a swinging member. An impact tool includes a motor 111, a swinging member 129 that swings in the axial direction of a tool bit 119 by rotation of the motor 111, a driving element 141 that is caused to reciprocate by swinging movement of the swinging member 129 and a first air chamber 143a in which pressure is fluctuated by reciprocating movement of the driving element 141, and the tool bit 119 is driven by pressure fluctuations of the first air chamber 143a. The impact tool further includes a second air chamber 163 in which pressure is fluctuated by swinging movement of the swinging member 129, and a dynamic vibration reducer 151 having a weight 155 and an elastic element 157 which exerts a biasing force on the weight 155.

Abstract: A power tool capable of performing vibration damping action in working operation, without an increase in size. The working tool includes a motor, a housing in which an internal mechanism driven by the motor is stored, a tool bit disposed on one end of the housing, a hand grip continuously connected to the other end of the housing, and a dynamic damper. The dynamic damper is disposed by utilizing a space between the housing and the internal mechanism so that the damping direction of the dynamic damper faces the longitudinal direction of the tool bit.

Abstract: It is an object of the invention to provide a technique for a reduction of an impact force cased by rebound of a tool bit after its striking movement in an impact power tool. The representative impact power tool includes a tool body, a hammer actuating member, a striker, a weight and an elastic element. A reaction force is transmitted from the hammer actuating member to the weight and the elastic element is elastically deformed when the weight moves ward by the reaction to absorb the reaction force. The invention is characterized in that the mass of the weight is set to about 40% or more of the mass of the striker.

Abstract: A power tool capable of performing vibration damping action in working operation, without an increase in size. The working tool includes a motor, a housing in which an internal mechanism driven by the motor is stored, a tool bit disposed on one end of the housing, a hand grip continuously connected to the other end of the housing, and a dynamic damper. The dynamic damper is disposed by utilizing a space between the housing and the internal mechanism so that the damping direction of the dynamic damper faces the longitudinal direction of the tool bit.

Abstract: It is an object of the invention to provide a technique that contributes to improvement of the vibration reducing performance of a dynamic vibration reducer in a power tool while realizing reduction in size of the dynamic vibration reducer. A representative power tool which linearly drives a tool bit to perform a predetermined operation on a workpiece includes a tool body and a dynamic vibration reducer. The dynamic vibration reducer has a weight and an elastic element. The weight has an internal space that extends in the axial direction of the tool bit from at least one end of the weight in said axial direction. One end of the elastic element is inserted and received in the internal space, while the other end of the elastic element is placed on the tool body directly or via the body side member.

Abstract: An electric hammer comprising a hammer bit performing hammering work on a work, a drive motor, a hammering piece driven by the drive motor to apply a hammering force to the hammer bit, and a mechanism for damping vibration generated during hammering. The damping performance of the electric hammer is enhanced by causing the driving amount applied to the damping mechanism to vary between a first mode where the damping mechanism generates vibration of the hammer bit subjected to an external force from the work during the load driving time and thereby optimizes the damping and a second mode where the damping mechanism generates vibration corresponding to the vibration of the hammer bit not subjected to an external force from the work during the no-land driving time and optimizes damping.

Abstract: An electric hammer comprising a hammer bit (313) performing hammering work on a work, a drive motor, a hammering piece (334) driven by the drive motor to apply a hammering force to the hammer bit, and a mechanism (371) for damping vibration generated during hammering. The damping performance of the electric hammer is enhanced by causing the driving amount applied to the damping mechanism (371) to vary between a first mode where the damping mechanism (371) generates vibration of the hammer bit (313) subjected to an external force from the work during the load driving time and thereby optimizes the damping and a second mode where the damping mechanism (371) generates vibration corresponding to the vibration of the hammer bit (313) not subjected to an external force from the work during the no-land driving time and optimizes damping.