Valve open-close indicating apparatus

Abstract

A valve open-close indicating apparatus comprises a cylindrical housing having two opposite ends in the axial direction thereof, a sleeve arranged in the housing for axial reciprocation between the opposite ends of the housing, and a cylindrical elastic member for urging the sleeve from both outer sides with respect to the axial direction so that the sleeve is normally situated in an intermediate position between the opposite ends. When a piston moves toward one end of the housing to open a valve, the sleeve is pressed toward the one end against the urging force of the cylindrical elastic member, and the indicating apparatus indicates "open." When the piston moves toward the other end to close the valve, the sleeve is pressed toward the other end against the urging force, and the indicating apparatus indicates "closed." When the piston is situated between the opposite ends, the sleeve is restored to the intermediate position by means of the cylindrial elastic member without being pressed by the piston, and the indicating apparatus indicates nothing. The sleeve is normally restored to the intermediate position by means of the cylindrical elastic member, and is moved as required, toward either of the opposite ends by means of the piston.

Dependencies are inferred from the claim text.