Pressure relief means for gauges

Claim 1

A PRESSURE GAUGE COMPRISING A GENERALLY CYLINDRICAL HOUSING OPEN AT ONE END, A GAUGE MOVEMENT INCLUDING A PRESSURE-SENSITIVE BOURDON TUBE MOUNTED WITHIN SAID HOUSING, A COVER PLATE OF GENERALLY DISC-LIKE FORM MOUNTED IN SAID HOUSING AND MOVABLE BETWEEN A SEATED POSITION CLOSING THE OPEN END OF SAID HOUSING TO SEAL THE INTERIOR THEREOF FROM THE ATMOSPHERE AND AN UNSEATED POSITION EXPOSING SAID OPEN END FOR VENTING THE INTERIOR OF SAID HOUSING TO THE ATMOSPHERE, MEANS DEFINING AN ANNULAR GROOVE ON THE INNER PERIPHERAL SURFACE OF SAID HOUSING, BIASING MEANS IN SAID HOUSING OPERABLE TO NORMALLY RETAIN SAID PLATE IN THE SEATED POSITION, AND OPERABLE IN RESPONSE TO EXCESSIVE PRESSURES IN SAID HOUSING TO PERMIT MOVEMENT OF SAID COVER PLATE TO SAID UNSEATED POSITION, SAID BIASING MEANS CONSISTING OF A RESILIENT ANNULUS MOUNTED IN SAID ANNULAR GROOVE HAVING A RADIALLY INWARDLYPROJECTING ARM WITH ITS TERMINAL END AT APPROXIMATELY THE CENTER OF SAID ANNULUS, MEANS DEFINING AN INTERNALLYTHREADED OPENING IN SAID TERMINAL END, AND A FASTENER CONNECTED TO SAID COVER PLATE HAVING A THREADED PORTION ENGAGEABLE WITHIN SAID THREADED OPENING IN SAID TERMINAL END OPERABLE TO FLEX SAID ARM TOWARD SAID COVER PLATE AND THEREBY URGE SAID COVER PLATE TO SAID SEATED POSITION.