Automatic free wheeling hub assembly

An automatic free wheeling hub assembly adapted for a four wheel drive vehicle to drivingly connect a wheel to the vehicle drive axle, said vehicle including a wheel hub mounted upon a drive axle shaft;

• said hub assembly comprising a support having an axial bore through which the axle shaft extends;
• a universal joint axially aligned with and spaced from said axle shaft and projected into said support;
• means journalling said axle shaft upon said support;
• means axially securing said axle shaft upon said support;
• means journalling said universal joint upon said support;
• means axially securing said universal joint to said support;
• said axle shaft having at one end thereof internally splined teeth;
• said universal joint having a cavity aligned with the axle shaft;
• said universal joint at said cavity being provided with internally splined teeth matching and axially aligned with the internally splined teeth provided at said one end of said axle shaft;
• an axially movable cylindrical clutch disc positioned within said cavity having an end face, said clutch disc having external teeth matching and movable along said internally splined teeth of said universal joint and being selectively engagable with the internally splined teeth provided at said one end of said axle shaft;
• fluid responsive actuating means including a movable member mounted within said cavity and axially abutting said end face;
• said movable member dividing said cavity into a pair of chambers upon its opposite sides;
• a resilient element between said clutch disc and shaft axially biasing said clutch disc completely within the cavity of said universal joint, out of engagement with the internal teeth of said axle shaft;
• said fluid responsive actuating means being responsive to a pressure differential in said chambers thereby moving said movable member and said clutch disc axially in said cavity overcoming said resilient element effecting engagement of the teeth of said clutch disc and said axle shaft, part of the teeth of said clutch disc remaining engaged with the internal teeth of said universal joint, said clutch disc functioning as a connecting element between said axle shaft and said universal joint;
• said wheel hub and axle shaft, when disengaged from said clutch disc, being adapted to turn freely as a unit, independent from said clutch disc, support and universal joint.