Fluid truck snubber

Claim 1

In a railway truck snubber assembly adapted to be interposed in a spring group intermediate a bolster member and side frame member of a railway truck assembly, the improvement comprising: a hydraulic snubber having a piston assembly telescopically movable with respect to a snubber casing, along an axis; said piston assembly having one end portion thereof slidably received within said snubber casing; biasing means received within said casing and operative to bias said piston assembly away from said casing along said axis; other biasing means adapted to be directly interposed intermediate said snubber and one of such members to bias said snubber towards the other of such members; said other biasing means being operationally adapted to have one end portion thereof engage a piston rod of said piston assembly adjacent the other end portion thereof and to have the other end portion of said biasing means directly communicate with the one of such members; said other biasing means being operative to bias said snubber out of operative engagement with the one of such members when such railway truck assembly is normally operating in an unloaded condition; the biasing force of said other biasing means being always less than the biasing force of said biasing means; and said other biasing means and said snubber being cooperable to initiate hydraulic snubbing by said snubber substantially only when such railway truck assembly is normally operating in a loaded condition, the bias of said other means is partially overcome and said snubber is in operative engagement with both of such members.