US Patent 7588484 Mounting system for grinding wheels and the like

A mounting system for rotating tools such as grinding wheels in a hand-held power tool, includes a hub mountable to the tool drive shaft and a rotating tool element removably affixable to the hub. The tool has at least one flange that engages a corresponding circumferential groove in a hub wall. Both the hub and tool have complimentary lock elements to frictionally retain the tool in a releasably fixed orientation upon the hub. One of the lock elements is in the form of a depression, while a mating element located on the other ports is a complimentary projection.