Dual rate spring with elastic spring coupling

Abstract

A supportive spring system particularly adaptable to vehicles such as railway cars that are operated with widely variable loads from empty to fully loaded condition. Such a spring system utilizing a plurality of helical spring units comprises multiple nested springs with primary springs having greater axial length than one or more secondary springs so that the primary springs alone provide the necessary supportive capacity to yieldingly support the weight due to an empty or slightly loaded car. When cars are heavily loaded, the secondary springs also become supportive and all sets of springs act in unison. To prevent the secondary springs from bouncing and becoming misaligned due to the vehicle's movement on the track, the lower coterminating end coils of the primary and secondary springs are yieldingly bonded together by an elastomeric material.

Dependencies are inferred from the claim text.