US Patent 7189039 Tool coupling for rotating tools

A tool assembly includes first and second tool bodies, a tool coupling interconnecting the tool bodies, and a drawing member for drawing the tool bodies together along a common longitudinal axis. The tool coupling includes a male portion disposed on one of the tool bodies, and a female portion disposed on the other of the tool bodies. The male portion has a plurality of tongues spaced apart around the axis, the tongues being flexible in a radial direction with reference to the longitudinal axis. The female portion has a non-circular recess defining a plurality of corner portions receiving respective ones of the flexible tongues for radially steering the tool bodies during axial mating thereof.