Helicopter rotor head mounting assembly

Claim 1

In a helicopter rotor head mounting assembly having an elogated rotor drive shaft, said rotor shaft being substantially cylindrical with an inward taper near the upper end thereof, and having a threaded portion beginning proximate the smallest diameter portion of said taper and extending upwardly the remaining length of said drive shaft, said rotor shaft having a vertically splined portion about the outer surface thereof below said taper, a rotor hub adapted to carry a plurality of helicopter rotor blades received by said rotor shaft, said hub having a longitudinal bore therethrough with a first tapered portion at the upper end thereof conforming to said taper on said rotor shaft, said bore being internally splined below said first tapered portion to conform to and mate with said splined portion of said rotor shaft for secure rotation therewith, said bore expanding radially outwardly and downwardly at a location below the internal splines thereof to produce a second tapered portion therewithin, means associated with said threaded portion for applying a force downwardly on said hub to firmly engage said taper of said rotor shaft with said first tapered portion of said hub; the improvement comprising: an annular split cone mounted between said rotor shaft and said hub at the location of said second tapered portion, said split cone having a cylindrical inner surface conforming to said rotor shaft and a tapered outer surface conforming to and mating with said second tapered portion of said hub bore, said split cone having an upper edge free from engagement with both said rotor shaft and said hub, an annular plate, means securing said plate to the bottom of said hub around said rotor shaft, a plurality of circumferentially spaced loading means carried by said plate, each of said loading means being adapted to apply a radially directed force to said split cone independently, thereby distributing the radially directed force to effect a uniform forced engagement between said rotor shaft and said inner surface of said split cone.