Black Decker Inc.

Keith E McQuaid

Steven J Phillips

David A Miller

Michael F Cannaliato

Oleksiy P Sergyeyenko

Oleksiy Petrovych Sergyeyenko

Christopher Wade Shook

Fugen Qin

Keith D Flaharty

Lyle Matson

A power tool is provided which accommodates interchangeable tool heads. The power tool includes: a tool body having a housing and an electric motor mounted within the housing, as well as a tool head that releasably attaches via a mechanical connection and an electrical connection to the tool body. The tool releasably connects to the output shaft of the electric motor when the tool head is attached to the tool body. A tool switch interposed between a power source for the electric motor and the electric motor is operable to supply power from the power source to the electric motor. A tool accessory switch interposed between the tool accessory and the power source for the electric motor is operable to supply power from the power source via the electrical connection to the tool accessory, thereby providing the tool operator independent control of the tool accessory.

Power tool having interchangeable tool heads with an independent accessory switch

A simplified control scheme is presented for use in a power tool. The power tool may be comprised of two or more lithium-ion battery cells connected in series and operable to drive the motor in the tool. A charging circuit is configured to receive a charging current from an AC adapter and to supply the charging current to the battery cells. A microcontroller monitors the voltage of the battery cells and terminates charging of the battery cells in accordance with the monitored voltages of the battery cells. The microcontroller does not receive power from the battery cells but is only powered by the AC adapter. Of note, each of the battery cells preferably employs an electrolyte composition comprised of a redox shuttle material. In combination with other tool components, the use of the redox shuttle material reduces or eliminates the need for expensive charge and discharge controls, thereby reducing the cost of the tool.

Charge control scheme for use in power tools

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Baltimore, MD, United States of America

Keith E McQuaid