Other

Tomoo Muramatsu

Yutaka Matsunaga

Kazuyoshi Horikawa

Shinichi Nakane

Masatoshi Sugiura

Masahiko Sakoh

A charging system includes an electric power tool (,) and a charger (,) having internal rechargeable batteries (,) and a controller (,) for monitoring the charge/discharge level of the batteries (,). The electric power tool (,) additionally includes a pair of charge terminals (,) for carrying current to charge the batteries (,), a temperature terminal (,) for outputting to the charger (,) data on the temperature of the batteries, and a data terminal (,) for outputting to the charger data on the battery charge/discharge level from the controller (,). The charger (,) includes a pair of charge terminals (,), a temperature terminal (,), and a data terminal (,) that are electrically connected to the corresponding tool terminals when the tool (,) is set on the charger for a charge. The charging system indicates the remaining charge level on an indicator unit (,) based on the received data on the battery charge/discharge level and changes the amount of the charging current based on the data on the battery charge/discharge level and the battery temperature data received from the tool (,).

Power tool charging system having a charge level indicator and charge control functions

An improved charging system for preventing battery deterioration and for accurate indication of the remaining battery charge level includes an electric power tool (,) and a charger (,). The electric power tool (,) is provided with an internal rechargeable batteries (,) and a second controller (,). The charger (,) is provided with circuitry for charging, a microcomputer (,), and discharge circuitry which is comprised of a manually-operated battery refreshing button (,), a discharge relay (,) and a discharge resistor (,). Upon depression of the battery refreshing button (,), the microcomputer (,) causes the batteries (,) of the electric power tool (,) to be charged to a full level and discharged to a predetermined level twice. When the two-cycle operation of full charge and discharge is completed, the second controller (,) of the electric power tool (,) updates the remaining charge level of the batteries (,).

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Nisshin, Japan

Tomoo Muramatsu