(under subclass 418) Apparatus in which the valve means comprises a main or primary valve which is movable by fluid under pressure to control the flow of motive fluid to or from the motor and a secondary or pilot valve operable to control the application of pressure fluid to the main valve, or a fluid actuator therefor, so as to control movement of said main valve, said fluid under pressure being separate or separated from the motive fluid controlled by the main or primary valve and not entering the working chamber.
SEE OR SEARCH THIS CLASS, SUBCLASS:
304+, for cyclically operable expansible chamber motors having a pilot valve controlled distributor. NOTE "PLACEMENT OF PATENTS" IN THE CLASS DEFINITION AND THE PARAGRAPHFOLLOWING THE TITLE IN THE SCHEDULE OF THIS CLASS.
