QUICK-CHANGE DEVICE

A quick-change device for a rotary power tool， such as a circular saw， comprising: a grip hub; a threaded bolt; a bolt key; wherein the bolt key is connected to the threaded bolt， such that the bolt key has at least an extended position and a collapsed position; wherein the threaded bolt is configured to pass through a bolt hole of the grip hub and threadably connect to a spindle of a circular saw; wherein the bolt key is configured to be able to be unscrewed from the spindle when in the extended position， such that an external tool is not needed to remove the threaded bolt from the spindle; wherein the bolt key is configured to matingly stow next to the grip hub when the bolt key is flipped down into the collapsed position; and wherein the threaded bolt may be quickly and safely removed and reengaged for the purpose of switching one or more saw blades.