Self-indicating relief valve

Claim 1

A RELIEF VALVE COMPRISING (A) A HOUSING HAVING A LONGITUDINAL PASSAGE AND AN INLET AND AN OUTLET COMMUNICATING WITH SAID PASSAGE, (B) SAID HOUSING BEING PROVIDED WITH A SHOULDER PORTION EXTENDING INWARDLY INTO SAID PASSAGE TO DEFINE A VALVE SEAT SURFACE EXTENDING IN A PLANE SUBSTANTIALLY NORMAL TO THE AXIS OF SAID PASSAGE, (C) VALVE MEANS PIVOTALLY CARRIED BY SAID HOUSING IN SAID PASSAGE, (D) BIASING MEANS CARRIED BY SAID HOUSING AND ENGAGING WITH SAID VALVE MEANS TO URGE SAME TOWARD SAID INLET AND INTO SEATING ENGAGEMENT WITH SAID VALVE SEAT SURFACE WHEREBY TO NORMALLY CLOSE COMMUNICATION BETWEEN SAID INLET AND SAID OUTLET AND TO VARIABLY OPEN COMMUNICATION ONLY WHEN PRESSURE AT SAID INLET EXCEEDS THE FORCE OF SAID BIASING MEANS, (E) POSITION INDICATING MEANS CARRIED EXTERIORLY OF SAID HOUSING AND OPERABLY CONNECTED TO SAID VALVE MEANS TO MOVE INTERMEDIATE A FIRST POSITION AND A SECOND POSITION RESPECTIVELY AS SAID VALVE MEANS MOVES INTERMEDIATE A FULLY OPENED AND A FULLY CLOSED POSITION, AND (F) INDICIA MEANS ASSOCIATED WITH SAID POSITION INDICATING MEANS TO INDICATE THE POSITION OF SAID VALVE MEANS.