US Patent 7814816 Power tool, battery, charger and method of operating the same

A power tool includes a housing assembly having a first housing portion and a second housing portion supported for pivoting movement relative to the first housing portion about a pivot axis. The first housing portion supports a motor. The second housing portion includes a chuck for supporting a tool element. The power tool also includes a gear supported within the housing assembly for rotation relative to at least one of the first and second housing portions about the pivot axis. The gear is operable to transfer drive force from the motor to the tool element.