Integral connection for plastic water pump impeller

Claim 1

An axially compact and integral connection between a plastic impeller and a coaxial metal impeller drive shaft, comprising, a male plug formed on said impeller having a surface with a non-circular cross section, a female socket formed on said drive shaft having a surface of non circular cross section that interfits closely with said male plug, a substantially rigid cylindrical wall on said drive shaft generally concentric with and surrounding said socket and facing in one radial direction, a cylindrical wall on said impeller that is generally concentric with and surrounds said plug with a diameter substantially equal to said drive shaft cylindrical wall and facing in the other radial direction, so that said drive shaft and impeller walls are also closely interfittable, said impeller cylindrical wall further being molded with a sufficiently small radial thickness so as to be partially flexible in the radial direction, a circular rib formed on one of said drive shaft and impeller cylindrical walls, and, a circular groove formed on the other of said drive shaft and impeller cylindrical walls and sized so as to fit closely within said circular rib, whereby, said impeller may be connected to said drive shaft by forcibly pushing said impeller onto said drive shaft, with said plug and socket interfitting so as to prevent turning between said impeller and drive shaft, and with said circular rib entering said circular groove as said impeller wall is simultaneously radially flexed, thereby axially locking said impeller to said drive shaft, said generally concentric plug, socket and cylindrical walls also occupying overlapping axial space so as give an axially compact connection.