Multi-headed power tool and fastening system for same and systems for fastening heads thereon

A power tool comprising:

• a housing;
• a motor and transmission assembly received in the housing;
• a trigger for activating the motor and transmission assembly;
• an output shaft driven by the motor and transmission assembly via a back end thereof for rotation about an axis;
• a head interface coupled to a forward end of the output shaft, the head interface comprising a mating surface and a circumferential groove;
• a tool head element configured for selective engagement on the head interface, the tool head element comprising:
• a housing including an input shaft configured to removably couple with the output shaft;
• and
• a collar comprising a plurality of locking elements, each locking element being biased inwardly towards the input shaft by biasing elements;
• wherein, upon attachment of the tool head element to the head interface, the plurality of locking elements are aligned into the circumferential groove of the head interface and held by the biasing elements therein to engage the tool head element onto the head interface and establish a drive connection between the output shaft and input shaft such that, when the motor and transmission assembly of the power tool is operated, the input shaft is configured to rotate with the output shaft about the axis and thus drive the tool head element.