Abstract: An electric tool switch mechanism includes a trigger switch for operating to at least rotate or stop a DC motor; and a power switch connected between the DC motor and a battery power source and closed when a pressed amount of the trigger switch exceeds a predetermined threshold value. The mechanism further includes a switching device connected between the DC motor and the battery power source via the power switch; a control circuit for controlling to turn the switching device on/off using a desired on-duty when the pressed amount of the trigger switch exceeds the threshold value; and a stopping unit that is controlled by the trigger switch for forcibly turning the switching device off before the power switch is changed from on to off when the trigger switch is released.

Abstract: A charging apparatus includes a battery pack, which includes a cell voltage detection unit outputting a signal if a detected cell voltage is not smaller than V1, and a temperature sensor detecting a temperature of the battery pack; and a charger, which includes a charging control circuit and a pack voltage detection unit detecting a voltage across two terminals of the battery pack. If the detected temperature from the temperature sensor exceeds 0° C., the charging control circuit switches to a constant voltage charging when the signal from the cell voltage detection unit is received; and if otherwise, the charging control unit switches to the constant voltage charging when receiving the signal or the detected pack voltage exceeds V2, whichever occurs first.

Abstract: An electrical apparatus includes an electrical apparatus main body and a battery pack. The electrical apparatus main body has a load, a manipulation switch, a power receiving electrode, a main body control unit for controlling the electric power supplied from the power receiving electrode in response to a manipulation of the manipulation switch, a signal generation unit for generating an on-manipulation signal if the manipulation switch is switched on, and a main body signal electrode for outputting the on-manipulation signal. The battery pack has a battery, a power supplying electrode, a battery control unit for controlling the electric power supplied from the battery to the power supplying electrode, a battery signal electrode for receiving the on-manipulation signal, and a power supplying unit for starting a power supply from the battery to the battery control unit when the battery signal electrode receives the on-manipulation signal.

Abstract: A battery pack for a power tool has a less-current consuming over-discharge protection. The battery pack includes a battery stack composed of a plurality of series connected secondary cells, and a discharge detector configured to monitor a cell voltage across each of the secondary cells and to provide a discharge stop signal when any one of the cell voltages becomes lower than a predetermined threshold. The discharge stop signal is fed to deenergize the power tool. The discharge detector is composed of a voltage monitor and a power controller. The voltage monitor includes a plurality of comparators and a plurality of constant voltage elements each providing a constant voltage determining the threshold. Each comparator is configured to compare each cell voltage with the threshold to give a comparison result. The voltage monitor is energized by the battery stack to provide the discharge stop signal based upon the comparison results.

Abstract: An impact power tool includes an impact mechanism for applying a striking impact to an output shaft by using an output power of a motor. A strike detection unit detects the striking impact applied by the impact mechanism to obtain a striking timing and a striking speed detection unit calculates a striking speed from the striking timing obtained by the strike detection unit and a rotation angle of the motor obtained by a rotation angle detection unit. A control unit counts the number of striking impact detected by the strike detection unit and stops the motor if the number of striking impact reaches a predetermined strike number. The control unit is designed to correct the predetermined strike number when the striking speed obtained in the striking speed detection unit is equal to or lower than a specified striking speed.

Abstract: A rotary impact tool can be used in a work especially precision or finishing of fastening is important. The rotary impact tool comprises a rotary driving mechanism including a driving source for rotating a driving shaft, a hammer fixed on the driving shaft, an output shaft to which a driving force is applied by impact blow of the hammer, a torque setting unit used for setting a fastening torque, a processor for calculating fastening torque from impact blow of the hammer, a rotation speed setting unit used for setting rotation speed of the driving shaft, and a controller for rotating the driving shaft of the rotary driving mechanism in a rotation speed set in the rotation speed setting unit and for stopping rotation of the driving shaft of the rotary driving mechanism when the fastening torque calculated in the processor becomes equal to or larger than a reference value of fastening torque previously set in the torque setting unit.

Abstract: An electric tool switch mechanism includes a trigger switch for operating to at least rotate or stop a DC motor; and a power switch connected between the DC motor and a battery power source and closed when a pressed amount of the trigger switch exceeds a predetermined threshold value. The mechanism further includes a switching device connected between the DC motor and the battery power source via the power switch; a control circuit for controlling to turn the switching device on/off using a desired on-duty when the pressed amount of the trigger switch exceeds the threshold value; and a stopping unit that is controlled by the trigger switch for forcibly turning the switching device off before the power switch is changed from on to off when the trigger switch is released.

Abstract: A charging device for charging battery packs includes charging terminals including a first charging terminal to be connected to an electrode of a first battery pack and a second charging terminal to be connected to an electrode of a second battery pack. Here, the first and the second battery pack are different in kind. Further, the charging device includes a conversion unit for supplying electricity to the first charging terminal when the electrode of the first battery pack is connected to the first charging terminal and supplying electricity to the second charging terminal when the electrode of the second battery pack is connected to the second charging terminal.

Abstract: A charging apparatus includes a battery pack, which includes a cell voltage detection unit outputting a signal if a detected cell voltage is not smaller than V1, and a temperature sensor detecting a temperature of the battery pack; and a charger, which includes a charging control circuit and a pack voltage detection unit detecting a voltage across two terminals of the battery pack. If the detected temperature from the temperature sensor exceeds 0° C., the charging control circuit switches to a constant voltage charging when the signal from the cell voltage detection unit is received; and if otherwise, the charging control unit switches to the constant voltage charging when receiving the signal or the detected pack voltage exceeds V2, whichever occurs first.

Abstract: A battery pack for a power tool has a less-current consuming over-discharge protection. The battery pack includes a battery stack composed of a plurality of series connected secondary cells, and a discharge detector configured to monitor a cell voltage across each of the secondary cells and to provide a discharge stop signal when any one of the cell voltages becomes lower than a predetermined threshold. The discharge stop signal is fed to deenergize the power tool. The discharge detector is composed of a voltage monitor and a power controller. The voltage monitor includes a plurality of comparators and a plurality of constant voltage elements each providing a constant voltage determining the threshold. Each comparator is configured to compare each cell voltage with the threshold to give a comparison result. The voltage monitor is energized by the battery stack to provide the discharge stop signal based upon the comparison results.

Abstract: When charging of a secondary battery is started, a power source section for supplying an electric current for charging the secondary battery gradually increases the supply amount of the current. If the charging current has reached a predetermined first threshold current, the power source section is operative to set the supply amount of the current to a predetermined constant current for a constant current charging. If a terminal voltage of the secondary battery has reached a predetermined threshold voltage, the power source section is operative to supply a predetermined voltage for a constant voltage charging to the secondary battery.

Abstract: A battery pack for a power tool of self-contained over-charge protection is proposed. The battery pack includes a battery stack composed of a plurality of series connected secondary cells, and a charge terminal connected through a charge current path to the battery stack for flowing a charge current from a charger. The battery pack includes an interrupter inserted in the charge current path, and an over-charge detector which detects a cell voltage across each of the secondary cells and actuates the interrupter to open the charge current path when any one of the cell voltages becomes higher than a predetermined threshold (VTH3). Thus, even if the charger fails to limit the charge current, the battery pack can itself protect the secondary cells from being over-charged.

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: 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: An electrical apparatus includes an electrical apparatus main body and a battery pack. The electrical apparatus main body has a load, a manipulation switch, a power receiving electrode, a main body control unit for controlling the electric power supplied from the power receiving electrode in response to a manipulation of the manipulation switch, a signal generation unit for generating an on-manipulation signal if the manipulation switch is switched on, and a main body signal electrode for outputting the on-manipulation signal. The battery pack has a battery, a power supplying electrode, a battery control unit for controlling the electric power supplied from the battery to the power supplying electrode, a battery signal electrode for receiving the on-manipulation signal, and a power supplying unit for starting a power supply from the battery to the battery control unit when the battery signal electrode receives the on-manipulation signal.

Abstract: A charging device for use in charging plural types of secondary batteries includes a power source unit for supplying a charging current to an object secondary battery, a battery type signal receiving unit for receiving a battery type signal, a battery temperature signal receiving unit for receiving a battery temperature signal, a blowing unit for blowing an air to the secondary battery, a storage unit for storing reference judging temperatures for determination of charging-incongruent temperatures of the plural types of secondary batteries, in a matching relationship with the types of the secondary batteries, and a control unit. The control unit allows the blowing unit to perform a blowing operation, if the temperature of the secondary battery exceeds a reference judging temperature, and to stop the blowing operation, if otherwise.

Abstract: A rotary impact tool can be used in a work especially precision or finishing of fastening is important. The rotary impact tool comprises a rotary driving mechanism including a driving source for rotating a driving shaft, a hammer fixed on the driving shaft, an output shaft to which a driving force is applied by impact blow of the hammer, a torque setting unit used for setting a fastening torque, a processor for calculating fastening torque from impact blow of the hammer, a rotation speed setting unit used for setting rotation speed of the driving shaft, and a controller for rotating the driving shaft of the rotary driving mechanism in a rotation speed set in the rotation speed setting unit and for stopping rotation of the driving shaft of the rotary driving mechanism when the fastening torque calculated in the processor becomes equal to or larger than a reference value of fastening torque previously set in the torque setting unit.

Abstract: A rotary impact tool can be used in a work especially precision or finishing of fastening is important. The rotary impact tool comprises a rotary driving mechanism including a driving source for rotating a driving shaft, a hammer fixed on the driving shaft, an output shaft to which a driving force is applied by impact blow of the hammer, a torque setting unit used for setting a fastening torque, a processor for calculating fastening torque from impact blow of the hammer, a rotation speed setting unit used for setting rotation speed of the driving shaft, and a controller for rotating the driving shaft of the rotary driving mechanism in a rotation speed set in the rotation speed setting unit and for stopping rotation of the driving shaft of the rotary driving mechanism when the fastening torque calculated in the processor becomes equal to or larger than a reference value of fastening torque previously set in the torque setting unit.

Abstract: A rotary impact tool can be used continuously for fastening a plurality of fastening members such as screws, bolts or nuts in tight fastening mode. The rotary impact tool comprises a rotary driving mechanism including a motor for rotating a driving shaft, a hammer engaged with the driving shaft, an output shaft to which a driving force is applied by impact blow of the hammer, a main switch operated by a user for controlling fastening operation, and a controller for controlling on and off of the motor. The controller has a normal fastening mode and a tight fastening mode, and a tight fastening mode setting switch used for setting the tight fastening mode is further comprised. When the tight fastening mode setting switch is switched on, the controller continuously drives the rotary driving mechanism so as to perform tight fastening operation continuously.

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.