Pitch stop assembly for variable pitch propulsor

Claim 1

A pitch change system for changing blade pitch on a variable pitch propulsor having a rotatable disc and a plurality of blades mounted to the disc for rotation therewith, each blade further being selectively rotatable about its longitudinal axis for pitch change, said pitch change system comprising a pitch change actuation assembly including a ballscrew being relatively rotatable with respect to the propulsor disc, a ballscrew nut operatively connected to the blades of the propulsor disc and threadably mounted on the ballscrew so as to rotate with the propulsor disc and axially translate along the ballscrew in response to a relative rotation between the ballscrew and the propulsor disc; and a pitch stop assembly; and a pitch change drive assembly operatively associated with the ballscrew of the pitch change actuation assembly for selectively rotating the ballscrew relative to the propulsor disc, said pitch change system characterized in that the pitch stop assembly of the pitch change actuation assembly comprises: a first stop means having ballscrew nut stop means associated therewith, said first stop means rotating and translating with the ballscrew nut; second stop means mounted for rotation with the propeller disc, said second stop means having a reverse pitch stop means, a feather pitch stop means, an overspeed pitch stop means and a minimum low pitch stop means associated therewith, said second stop means disposed in operative relationship with said first stop means whereby translation of the ballscrew nut relative to the ballscrew is precluded upon engagement of said ballscrew nut stop means with any one of said pitch stop means of said second stop means; and means for selectively rotating said second stop means relative to said first stop means whereby said ballscrew nut stop means may selectively bypass at least one of said feather pitch stop means and said overspeed pitch stop means.