Abstract: A wireless communications system includes a tool having a first wireless communications unit and a transceiver having a second wireless communications unit to receive a signal transmitted from the first wireless communications unit. Further, the transceiver has a setting unit for setting wireless communications parameters for wireless communications between the first and the second wireless communications unit, and the tool has a tool control unit for setting in the wireless communications unit the wireless communications parameters set by the setting unit and transmitted to the tool by wireless communication.

Abstract: A charging circuit includes a battery pack provided with one or more secondary batteries and a battery charger for charging the secondary batteries, the battery pack being detachably attachable to the battery charger. The charging circuit further includes a control unit for performing a charging control, a monitoring unit for detecting charged voltage of the secondary batteries to determine completion of charging, a storage unit storing charging data for use in the charging control of the control unit and determination of the charging completion of the monitoring unit and a changing unit for changing the charging data. The monitoring unit and the storage unit are arranged in the battery pack, and the changing unit and the control unit are arranged in the battery charger.

Abstract: A changeover operation device, for changing over the positions of at least two components to establish three or more speed modes in a speed changer mechanism accommodated within a housing having an opening, includes operation handles arranged in a corresponding relationship with the components. Each of the operation handles is movable between two specified positions along a specified operation direction to change over the positions of the components. The operation handles are continuously arranged within the opening of the housing, one of the operation handles being partially overlapped with the other.

Abstract: An electric power tool includes a motor, a speed reduction mechanism, a power output unit, a control circuit unit, and a housing. The housing provided with an air supply-exhaust hole. The motor includes a stator core wound with coils, a rotor core and an electronic circuit unit. The electronic circuit unit includes a circuit board, electronic components arranged in the circuit board and including a switching element, coil connection portions arranged in the circuit board and connected to the coils and a control circuit connection portion arranged in the circuit board and connected to the control circuit unit. The motor further includes a radiator member for dissipating heat generated in the switching element of the electronic circuit unit and an insulating cover member molded to cover the electronic components, the coil connection portions, the control circuit connection portion, the circuit board and the radiator member.

Abstract: A battery pack which is detachably connected to a charger and charged by connecting thereto, includes a battery assembly including a plurality of secondary batteries serially connected; a pair of power terminals connected to a negative and a positive electrode of the battery assembly, respectively; a control circuit adapted to individually detect voltages across respective secondary batteries and output a charge control signal to the charger when the detected voltages exceed a predetermined value; a signal terminal adapted to output the charge control signal to the charger; and a temperature measurement element for detecting a temperature of the battery assembly. Further, the control circuit changes the predetermined value to be compared with the detected voltages based on the detected temperature of the temperature measurement element.

Abstract: A rotary impact tool includes a drive power source for producing rotational power, a drive shaft driven by the rotational power supplied from the drive power source, an output shaft operatively connected to the drive shaft for receiving the rotational power, an impact mechanism operatively couplable with the drive shaft. The rotary impact tool further includes a changeover unit for changing over an impact mode in which the impact mechanism is operated and a drill driver mode in which the rotational power produced by the drive power source is transferred to the output shaft without operating the impact mechanism and a multi-stage speed reduction mechanism for transferring the rotational power produced by the drive power source to the output shaft through the drive shaft at variable speeds in at least three speed modes including a low speed mode, a middle speed mode and a high speed mode.

Abstract: A rechargeable electric power tool includes a motor driven by a secondary battery, a switching element for regulating power distribution to the motor, a motor control unit for controlling rotation of the motor through the switching element, a lead wire for supplying a drive current to the motor therethrough and a trigger switch changed over by a user for turning on or off the drive current supplied to the motor through the lead wire. In the rechargeable electric power tool, upon changeover of the trigger switch, a microcomputer determines a magnitude relation between a detected temperature outputted from a first thermistor and a first temperature threshold value. If the detected temperature is determined to be greater than the first temperature threshold value, the microcomputer is set in a limited operation mode in which a revolution number of the motor is limited to a predetermined value or less.

Abstract: A charging controller connected to at least one of secondary cells and detachably connected to a charger or a cell driver, the charging controller including: a charging amount control circuit detecting a cell voltage of each secondary cell and outputting a charging control signal for instructing the charger to reduce a charging current when the detected cell voltage exceeds the target voltage; and a protection circuit detecting a cell voltage of each secondary cell and cutting off a current path from the charger to the secondary cell when the detected cell voltage exceeds the upper limit voltage, the protection circuit operating by using the secondary cell as a power source while at least the charger is not connected. In the charging controller, while neither the charger nor the cell driver are connected, the charging amount control circuit does not operate.

Abstract: A battery pack includes cylindrical columnar battery cells arranged at least in two rows and two columns along vertical and horizontal directions orthogonal to center axes of the battery cells. Each of the battery cells includes an electrode terminal formed in one end portion thereof. The battery pack further includes a connector plate to which the electrode terminals of four vertically and horizontally adjoining battery cells are joined. The connector plate is arranged to parallel connect each pair of the battery cells adjoining in the same direction to form battery cell blocks. The connector plate is configured to serially connect the battery cell blocks. The center axes of the battery cells are positioned at vertexes of a parallelogram when the vertically and horizontally adjoining battery cells are seen at one end side thereof. The connector plate has a contour conforming to respective sides of the parallelogram.

Abstract: A brushless motor driving circuit includes a battery for supplying a power to the brushless motor driving circuit; a driver circuit; a bridge circuit including a plurality of N-channel FETs; a control unit for rotating a brushless motor by switching the bridge circuit through the driver circuit based on a rotor position detection signal; a floating voltage generator for applying a voltage to a first group of the FETs of the bridge circuit; and a converter which is powered from the battery. The converter has an output connected to an input of the floating voltage generator for the first group of the FETs of the bridge circuit and an input of the driver circuit for a second group of the FETs of the bridge circuit to dedicatedly supply a power to gates of the FETs, and the control unit is powered from the battery without using the converter.

Abstract: An electric power tool includes a three-phase bridge motor circuit including upper and lower switching units of U, V and W phases arranged in upper and lower rows; a brushless motor rotationally operated by an electric power supplied through the motor circuit; and temperature detecting units for detecting temperatures of the switching units to output detection results such that the operation of the brushless motor is restrained or stopped depending on the detection results outputted from the temperature detecting units. The motor circuit is formed by mounting the switching units at six points on a mounting surface of a circuit board, and the temperature detecting units are arranged on a surface of the circuit board opposite to the mounting surface.

Abstract: An electric power tool includes a cylindrical reducer case accommodating the speed reduction mechanism. The speed reduction mechanism includes a planetary gear train and a movable member which is axially slidable to be engaged with or disengaged from the planetary gear train. The electric power tool includes the reducer case including a slide hole formed through a sidewall of the reducer case and axially extended and a rotary plate which is rotatable around a periphery of the reducer case about the axis, the rotary plate including an operation slot formed axially obliquely and overlapped with the slide hole; a supporting member radially outwardly protruded from the movable member and extended through the slide hole and the operation slot; and a biasing unit for applying a pressing force to the supporting member in a moving direction of the supporting member when the rotary plate is rotated to a position.

Abstract: An electric power tool includes a motor; a speed reducer for transferring a rotational power of the motor at a reduced speed; and a reduction ratio changing unit for changing a reduction ratio of the speed reducer. The speed reduction mechanism includes an axially slidable changeover member and a gear member, the changeover member being engaged with or disengaged from the gear member depending on an axial slide position thereof. The reduction ratio changing unit includes a shift actuator for axially sliding the changeover member, a driving state detector for detecting a driving state of the motor, a slide position detector for detecting a slide position of the changeover member and a controller for driving the shift actuator and for changing a drive control of the shift actuator depending on detection results of the slide position detector unit and the driving state detector unit, respectively.

Abstract: An electric power tool includes a motor; a speed reducer for transferring a rotational power of the motor at a reduced speed; and a reduction ratio changing unit for changing a reduction ratio of the speed reducer. The speed reduction mechanism includes an axially slidable changeover member and a gear member, the changeover member being engaged with or disengaged from the gear member depending on an axial slide position thereof. The reduction ratio changing unit includes a shift actuator for axially sliding the changeover member, a driving state detector for detecting a driving state of the motor, a slide position detector for detecting a slide position of the changeover member and a controller for driving the shift actuator and for temporarily decreasing or increasing a rotational power of the motor depending on detection results of the driving state detector and the slide position detector, respectively.

Abstract: In a rechargeable electric power tool, upon changeover of a trigger switch, a microcomputer determines the magnitude relation between the detected temperature outputted from the first thermistor and the first temperature threshold value, the second temperature threshold value and the third temperature threshold value, and the magnitude relation between the first calculated temperature increase rate and the first preset temperature increase rate. If the detected temperature is determined to be greater than the first temperature threshold value or if the first calculated temperature increase rate is determined to be greater than the first preset temperature increase rate after the detected temperature has been determined to be greater than the second temperature threshold value, the microcomputer is set in a limited operation mode in which the revolution number of the motor is limited to a predetermined value or less.

Abstract: An installation structure of a temperature sensor in a brush motor includes a holding plate; a metal-made fixing base; and a brush holder arranged on the fixing base to hold a brush in place. The metal-made fixing base is provided on the holding plate, and the fixing base includes a sensor attachment portion to which the temperature sensor is attached. Further, the sensor attachment portion is positioned outside the holding plate.

Abstract: A rotary impact tool includes a drive shaft rotationally driven by a rotational drive power source, a hammer arranged around the drive shaft, a ball engaging with a cam groove formed on the outer circumferential surface of the drive shaft and a cam groove formed on the inner circumferential surface of the hammer, an anvil engageable with the hammer along a rotational direction and a spring for biasing the hammer toward the anvil. The hammer is designed to rotate along a rotational locus decided by the cam groove of the drive shaft and the cam groove of the hammer. The rotational locus of the hammer as seen in a development view describes a curve in which the lead angle of the rotational locus varies continuously with the change in hammer rotation angle.

Abstract: A rotary tool includes an externally operable operation switch; a motor serving as a power source; a power transfer block for transferring the rotation of the motor; a load detection unit for detecting an amount of load of the motor; and a control unit for controlling the motor. The control unit is configured to perform an operation control by which the motor is controlled so that a rotation speed of the motor is increased in proportion to the operation amount of the operation switch and a feedback control by which the rotation speed of the motor is controlled depending on the detection result of the load detection unit. The control unit inhibits the feedback control during the time when the operation amount of the operation switch is equal to or less than a threshold and performing the feedback control only when the operation amount of the operation switch is greater than the threshold.

Abstract: A battery charger for charging a detachably attached battery pack by supplying an electric power from an external power source, the battery charger includes a notification unit for notifying a user of a charging operation by turning on or flickering a light-emitting member. The notification unit notifies the user of a power connection state of the battery charger by turning on or flickering the light-emitting member immediately after the battery charger is electrically connected to the external power source without attaching the battery pack thereto, and the notification unit turns off the light-emitting member after a predetermined period of time lapses and keeps the light-emitting member in an off-state until the battery pack is attached to the battery charger.

Abstract: An electric power tool includes a housing, a motor arranged within the housing, a power transmission unit arranged within the housing for transferring rotation of the motor to a work tool, a motor control unit arranged within the housing for controlling the rotation of the motor, and a trigger switch retractably provided to the housing for instructing the motor control unit to control the rotation of the motor. The electric power tool further includes a wireless communication device arranged within the housing for wirelessly communicating the work information on the content of works. The wireless communication device includes an antenna unit. The wireless communication device is covered with a shock-absorbing material. The antenna unit is arranged to lie higher than the trigger switch when the electric power tool is stored in a specified storage state.