Patent ID: 8196912

Claim:
A cold formed railcar spring comprising: a spring formed from a preform of thermoplastic polyester elastomer having a durometer hardness ranging between about 40 and about 45 on the Shore D scale, with said preform having a selected initial axial length and a generally cylindrical shape of a predetermined diameter between first and second axial ends thereof and defining an axial bore opening to said first and second ends, with said preform and said bore being substantially uniform in cross section perpendicular to a central axis of said preform, and wherein the elastomer of said preform is such that, upon being axially compressed at least 30% of the initial axial length of said preform, said elastomer will permanently retain a substantial portion of the length reduction after being compressed and whereby said preform is thereafter transmuted into said spring for absorbing, dissipating and returning energy imparted thereto; and first and second metal plates adapted to be mechanically fastened at the first and second ends, respectively, of said preform, with each plate having a pair of generally parallel and planar surfaces defining a predetermined thickness therebetween and a generally centralized bore extending through each plate, with each plate further including a profiled periphery, and with each plate further including a plurality of radially spaced mechanical fasteners extending generally perpendicular to the planar surfaces of said plate, with a plurality of said fasteners being formed as an integral part of each plate and having first and second generally parallel surfaces along with a barb extending from a side of said fastener, and wherein said barb defines a radial shoulder extending generally parallel to and spaced from the planar surface of the plate arranged in abutting relation with the axial end of said spring member such that, upon axial compression of said preform onto said plate, said fastener is pressed axially inward of one end of said preform and with elastomer material of said preform passing between the radial shoulder on said barb on said fastener and said plate whereby mechanically interlocking said plate to one end of said preform, and wherein each fastener is oriented relative to the central axis of the preform to influence radial expansion of said spring during a working cycle of said spring.