Air vent device for sealed housings

Claim 1

AN ASSEMBLY INCLUDING A SEALED DIFFERENTIAL HOUSING HAVING MOVABLE PARTS THEREIN IMMERSED IN A LUBRICANT AND A PAIR OF LEG PORTIONS, SAID MOVABLE PARTS AND LUBRICANT BEING HEATED DURING OPERATION OF SAID PARTS AND COOLED WHEN SAID PARTS ARE NOT IN USE CAUSING PRESSURE BUILD-UP AND SUBATMOSPHERIC OR VACUUM CONDITIONS, RESPECTIVELY, WITHIN SAID HOUSING, MEANS FOR RELIEVING SAID PRESSURE BUILD-UP AND VACUUM CONDITIONS COMPRISING A BODY SECURED TO ONE OF SAID HOUSING LEG PORTIONS ABOVE THE NORMAL LEVEL OF THE LUBRICANT, SAID BODY HAVING A PASSAGEWAY COMMUNICATING WITH SAID HOUSING AND FIRST AND SECOND APERTURES OPENING TO THE ATMOSPHERE AND COMMUNICATING WITH SAID PASSAGEWAY, PRESSURE RESPONSIVE MEANS WITHIN SAID BODY, MEANS BIASING SAID PRESSURE RESPONSIVE MEANS TOWARD A POSITION OVERLYING AND CLOSING SAID APERTURES, SAID PRESSURE RESPONSIVE MEANS BEING MOVABLE TO OPEN SAID FIRST APERTURE WHEN THE PRESSURE WITHIN SAID HOUSING EXCEEDS A FIRST PREDETERMINED LEVEL AND BEING MOVABLE TO OPEN SAID SECOND APERTURE WHEN SAID PRESSURE FALLS BELOW A SECOND PREDETERMINED LEVEL.