High pressure valve for railway car brake control valve device

摘要

A spool type valve arrangement in which a booster spring is employed to overcome static friction of the spool valve O-rings and thereby assure prompt actuation of the spool valve member. The arrangement is such that the booster spring is only active through a limited distance of travel from release position toward application position, this limited distance of spool valve travel being selected so as to occur prior to any transition of the port connections controlled by the spool valve. In this manner, the spool valve return spring force need not be increased in order to reset the spool valve sufficiently to reestablish the original spool valve port connections.