Dynamic seals for vehicle air suspensions

A vehicle suspension assembly comprising, in combination, at least two axles each having exterior portions adapted to be carried by parts of a vehicle body and interior portions adapted to lie within a sealed, air containing support assembly, said axles being spaced apart in front to rear relation, a wheel unit carried by each of said axles, said sealed support assembly including a pair of side plates, a track unit and a seal assembly, each of said side plates being supported in substantially airtight relation to said axle, each of said side plates having a given height and front and rear end portions extending respectively forwardly of said front axle and rearwardly of said rear axle, each of said side plates also including a smooth primary sealing surface facing the interior of said support assembly, at least one of said side plates having a passage therein for connection to a pressurized air supply, said track unit including an endless, air impermeable support track having opposed side margins and a center tread portion lying therebetween, said track having portions which are in contact with and trained over portions of said wheel units and positioned thereby so as to have a movement path defined by upper and lower run portions joined by rounded end portions, said seal assembly including a pair of air impermeable sealing diaphragms, each having inner and outer margins with the outer diaphragm margins being joined to said track side margins in airtight relation, an elongated inflatable primary seal unit with a body of tubular cross section, said seal body having a pair of inner margins, a pair of opposed sidewalls joined at their outer margins by an imperforate seal body end portion, one of said seal body sidewalls being imperforate and attached at its inner sidewall margin to said inner diaphragm margin in air tight relation and the other seal body sidewall having its outer margin forming a sealing surface which is disposed in substantially airtight opposed end face sliding sealing relation to said end plate sealing surface, said other seal body sidewall having its inner sidewall margin comprised of spaced apart webs having air entry openings therebetween, said webs having their inner margins affixed to both said one inner sidewall margin and said diaphragm inner margin, thereby forming a common inner diaphragm and seal margin, and means for supporting said common inner diaphragm and seal margin for movement along a path lying generally parallel to and spaced inwardly apart from the travel path of said track unit, whereby said sealing surface on said primary seal body will also follow a travel path parallel to the travel path of said track unit.