Lead screw driven shaft phase control mechanism

Claim 1

A phase controlling system between a rotatable driving member (215) and a rotatable shaft (202), said system characterized by: said driving member (215) being coaxially mounted to and axially affixed with respect to said shaft (202) and angularly rotatable therewith; an intermediate assembly including an axially shiftable member (228) coaxially mounted with respect to said rotatable shaft and said driving member capable of axial movement relative thereto and for angular motion with respect to one of said shaft and said driving member as it moves axially; said intermediate assembly further including a carrier drive nut member (238) having an interior threaded portion (242) and being restrained from rotable movement but capable of axial movements relative to said shaft and said driving member; means attaching said shiftable member (228) and said carrier drive nut member (238) for axial movement together; a rotable jack shaft (243) coaxial with said rotatable shaft having an exterior threaded end portion (244) adapted to engage said interior threaded portion (242) of said carrier drive nut member (238); said rotable jack shaft (243) being operatively connected to an electric motor (204) for selected rotation whereby subsequent relative rotation between said threaded portions produces selective axial movement of said carrier drive nut member (238) and shiftable member (228) with respect to said rotatable shaft and driving member between predetermined first and second positions; said intermediate assembly (228, 238, and 243) providing a unidirectional drive, such as to allow the drive motor (204) to change the angular position of said shaft (202) with respect to said driving member (215) as set by said electric motor but to prevent torque forces exerted by said shaft to self-induce timing changes.