US Patent 9956677 Power tool with interchangeable power heads

A power tool system which includes a first base unit and a second base unit. The first and second base units each include a housing, a motor housed in the housing, a coupler which is operatively connected to and selectively drivable by the motor and a trigger for activating the motor to drive the coupler. The system also includes a first attachment head which is removably couplable with both the first base unit and the second base unit so that it can be driven by the respective motor of the base unit to which it is attached and a second attachment head which is removably couplable to the first base unit, but which is not couplable with the second base unit.