Abstract: A spring mounting cradle for an over-pressure valve assembly has integral valve-element camming surfaces provided adjacent the lower ends of a pair of the bent legs forming the cradle.

Abstract: A spring mounting cradle for an over-pressure valve assembly has integral valve-element camming surfaces provided adjacent the lower ends of a pair of the bent legs forming the cradle.

Abstract: A fail-safe fluid actuator comprising a piston slidably disposed within a cylinder. In the event of a pressure loss, the piston is urged to a fail-safe position by a plurality of externally mounted constant force spring mechanisms. In one embodiment the mechanisms are located at one end of the cylinder with a telescoping cover for protecting them from exposure and damage. In another embodiment the mechanisms are located at the side of the cylinder whereby the overall length of the actuator is significantly shortened. The fail-safe force applied to the piston by the spring mechanisms is externally adjustable, and they are readily accessible fur replacement or repair.

Abstract: A pressure relief valve for releasing fluid through a vent in a railway tank car, tank trucks and similar vessels. A valve disk is normally biased in a closed position by a plurality of constant-force springs of laminated steel tapes on drums supported on upright angle brackets symmetrically arranged around a valve seat. The pressure at which the valve opens is determined by a preselection of the number of springs, laminated tapes per spring, and the restoring force of each tape.