US Patent 7621815 Flexible clutch

A clutch is provided for releasably coupling an axially rotatable driving shaft to a coaxial driven shaft. The clutch comprises a gear, having a plurality of cogs, coaxially secured to one of said driving shaft or said driven shaft; and a receptor coaxially secured to the other of said driving shaft or said driven shaft. The receptor comprises a hub and a plurality of flexible extension segments defining a cavity matingly engaging the gear cogs. When the driven shaft encounters rotational resistance greater than a range of normal operation, the extension segments flex out of engagement with the gear cogs to allow rotation of the driving shaft without rotation of the driven shaft.