Abstract: A charging control system. The system has a function as a switch controller which includes a charge mode judging executor 66, a charging time monitoring executor 68 and a switch controlling executor 72. The executor 66 judges whether present control is a constant current control or a constant voltage control. The executor 68 monitors whether or not a constant current charging time exceeds a threshold time by utilizing a judging result of the executor 66. The executor 72 turns a switch 54 off when a monitoring result of the executor 68 indicates that the constant current charging time exceeds the threshold time.

Abstract: A transportable power tool such as an impact driver has a power unit in which a motor and a reducer-transmitter are contained, a grip and a coupler unit with which a battery pack is coupled. Maximum dimensions of the power unit and maximum dimensions of the battery pack in a direction perpendicular to both of center axes of the power unit and the grip and in a direction parallel to the center axis of the power unit are larger than those of the grip in the same directions. Operation members used for selecting an operation mode of the motor and a display device are provided at positions near to the grip from a line binding contacting portions of the power unit and the battery pack when the power unit and the battery pack are simultaneously contacted with the same plane in each state.

Abstract: In a power impact tool for fastening a fastening member, a torque for fastening the fastening member can be estimated without using a high-resolution sensor and a high-speed processor.

Abstract: In a power fastening tool for fastening a fastening member such as a screw or a fastening member, malfunction that driving of a motor is stopped before the fastening member is fastened completely can be prevented. A fastening judger judges that the fastening operation is completed when a value of an estimated torque T for fastening the fastening member becomes larger than a predetermined lower limit value T1 previously set by a user and a value of a torque variation ratio ??T varies from positive to negative. Thus, it is possible to prevent malfunction for stopping driving of a motor even when the value of the torque variation ratio ??T varies from positive to negative due to trouble before the vale of the estimated torque T becomes larger than the lower limit value T1.

Abstract: The battery pack used for the battery powered electrical device of the present invention comprises a case for accommodating at least two battery modules, a switching means provided on a side of the case, and an output terminal formed on the case. The switching means selectively closes and opens a series electrical connection of the at least two battery modules. The switching means cooperates with an actuator, which is provided on a side of a device's main body holding the battery pack detachably, to establish the series electrical connection when the case is attached to the device's main body, and to interrupt the series electrical connection when the case is detached from the device's main body.

Abstract: A charger includes a battery pack receiving therein a plurality of batteries and having a projection provided with a contacting terminal, and a charger section having a mounting hole provided with a charging terminal, the battery pack being set on the charger section with the projection mounted into the mounting hole of the charger section for charging the batteries. The battery pack has vent ports through a wall on the side having the projection, while the charger section has blast ports at positions opposing the vent ports and a blower disposed to be on a side of the mounting hole and below the blast ports, for blowing air from the blower, through the vent ports into the interior of the battery pack, for elevating blow rate to the battery pack, battery cooling and gas discharge out of the battery pack.

Abstract: A charger includes a battery pack receiving therein a plurality of batteries and having a projection provided with a contacting terminal, and a charger section having a mounting hole provided with a charging terminal, the battery pack being set on the charger section with the projection mounted into the mounting hole of the charger section for charging the batteries. The battery pack has vent ports through a wall on the side having the projection, while the charger section has blast ports at positions opposing the vent ports and a blower disposed to be on a side of the mounting hole and below the blast ports, for blowing air from the blower, through the vent ports into the interior of the battery pack, for elevating blow rate to the battery pack, battery cooling and gas discharge out of the battery pack.

Abstract: A charger includes a battery pack receiving therein a plurality of batteries and having a projection provided with a contacting terminal, and a charger section having a mounting hole provided with a charging terminal, the battery pack being set on the charger section with the projection mounted into the mounting hole of the charger section for charging the batteries. The battery pack has vent ports through a wall on the side having the projection, while the charger section has blast ports at positions opposing the vent ports and a blower disposed to be on a side of the mounting hole and below the blast ports, for blowing air from the blower, through the vent ports into the interior of the battery pack, for elevating blow rate to the battery pack, battery cooling and gas discharge out of the battery pack.

Abstract: A charger includes a battery pack receiving therein a plurality of batteries and having a projection provided with a contacting terminal, and a charger section having a mounting hole provided with a charging terminal, the battery pack being set on the charger section with the projection mounted into the mounting hole of the charger section for charging the batteries. The battery pack has vent ports through a wall on the side having the projection, while the charger section has blast ports at positions opposing the vent ports and a blower disposed to be on a side of the mounting hole and below the blast ports, for blowing air from the blower, through the vent ports into the interior of the battery pack, for elevating blow rate to the battery pack, battery cooling and gas discharge out of the battery pack.

Abstract: A charger includes a battery pack receiving therein a plurality of batteries and having a projection provided with a contacting terminal, and a charger section having a mounting hole provided with a charging terminal, the battery pack being set on the charger section with the projection mounted into the mounting hole of the charger section for charging the batteries. The battery pack has vent ports through a wall on the side having the projection, while the charger section has blast ports at positions opposing the vent ports and a blower disposed to be on a side of the mounting hole and below the blast ports, for blowing air from the blower, through the vent ports into the interior of the battery pack, for elevating blow rate to the battery pack, battery cooling and gas discharge out of the battery pack.

Abstract: A driving circuit for brushless motor has a measure for damping the motor with both upper side and lower side power MOSFET's of half-bridges in pairs which corresponding to three phase coils in bipolar system rendered to be in reverse operating state by turning off a single control power source. The circuit is thereby made realizable an effective motor damping with a simpler circuit structure.