Transmission synchronizer with shift inhibitor

In a manual transmission double-acting synchronizer clutch and speed gear assembly comprising;

• a main shaft with said clutch located intermediate high and low range speed gears journally mounted on said shaft, each said speed gear having an external splined tooth surface concentrically associated therewith, a clutch hub fixed on said shaft intermediate said speed gears having an external splined tooth surface, a shift sleeve having an internal splined tooth surface coupled to said hub external splined tooth surface adapted for slidable fore and aft travel on said hub for selective engaging either said fore or aft speed gear splined tooth surface, respectively, alternately coupling said speed gears for rotation with said shaft, a blocker ring concentrically surrounding said shaft intermediate each said speed gear and said clutch hub, one or more fore and aft internal and external sets of cone surfaces, a clearance between each said set of cone surfaces with an associated external cone surface for reciprocal movement relative thereto, means attaching each said external cone surface to an associated one of said speed gears, resilient thrust means for moving an associated one of said blocker rings toward its associated speed gear in shifting operation of said sleeve toward a selected speed gear to effect frictional engagement of said one blocker ring internal conical surface with its associated speed gear external internal cone surfaces providing cone torque therebetween, said hub formed with diametrically opposed keyways, each said keyway having a radially slidable locking key therein, spring means interconnecting said locking keys and operative to bias said keys inwardly to a predetermined location enabling said sleeve to be selectively shifted fore or aft into synchronized engagement with an associated speed gear, said locking keys operative during a predetermined rotational speed of said main shaft to extend outwardly under centrifugal force to a predetermined location, said extended keys adapted to contact associated stop faces or cam faces formed in said sleeve interior splines, whereby said sleeve is permitted to move in one axial direction to engage one of said speed gear spline surfaces by virtue of its cam faces causing said locking keys to be moved to their predetermined retracted locations, and whereby said sleeve is prevented from moving in the other axial direction obviating engagement with the other speed gear spline surface.

In a double-acting gear synchronizer clutch assembly comprising fore and aft range speed ratio gears journally mounted on a main drive shaft, each said gear having an externally splined surface fixed thereon, said clutch including an externally splined hub fixed on said shaft intermediate said gears and having fore and aft cylindrical portions, each said cylindrical portion encircling an associated fore and aft blocker ring surrounding said shaft, a clutch sleeve encircling said hub portion and having internal spline teeth in continual engagement with said hub portion external spline teeth, said sleeve being axially movable in either a fore or aft direction by a shifting arrangement such that said sleeve internal spline teeth are adapted to selectively engage with either said fore or aft gear externally splined surface, and resilient loading means for moving each said blocker ring toward its associated fore or aft gear during the axial shifting operation of said sleeve toward each said gear to effect frictional engagement of associated fore an aft internal and external cone means selectively interconnecting each said blocker ring with its associated fore or aft gear, whereby upon said sleeve moving from its neutral position either fore or aft wherein associated cone means of the fore or aft blocker ring and gear are fictionally loaded by said resilient loading means developing cone means torque therebetween, whereby the selected blocker is rotated in one direction to an indexed position, and wherein upon the index torque developed in said indexed position exceeding the cone torque developed by its associated cone means its associated blocker ring is rotated in the opposite direction allowing said sleeve internal splines to pass into lock-up engagement with its associated gear external splined surface as said sleeve completes its full axial travel, the improvement wherein:

• said hub formed with diametrically opposed keyways, each said keyway having a radially slidable locking key therein, spring means interconnecting said locking keys and operative to bias said keys inwardly to a predetermined location enabling said sleeve to be selectively shift fore and aft into synchronized engagement with an associated speed gear, said locking keys operative during a predetermined rotational speed of said shaft to extend outwardly under centrifugal force to a predetermined location, said extended keys adapted to contact associated stop faces or cam surfaces formed in said sleeve interior splines, whereby said sleeve is permitted to move in one axial direction to engage one of said gear spline surfaces by virtue of said cam faces causing said keys to move inwardly to their predetermined retracted positions.