Flying helmets

Claim 1

A FLYING HELMET FITTED WITH A VISOR PIVOTED ABOUT A POINT ON SAID HELMET AND CAPABLE OF MOVEMENT BETWEEN AN UPPER OPEN POSITION AND A LOWER CLOSED POSITION, THE SAID HELMET INCLUDING A LEVER RESPONSIVE TO G-FORCES PIVOTED AT A POINT ON THE SAID VISOR ABOUT A GENERALLY HORIZONTAL AXIS, SPRING MEANS CONNECTING THE SAID LEVER TO THE SAID HELMET, AND AUTOMATIC LOCKING MEANS COMPRISING A PROJECTION ON THE SAID LEVER AND A COOPERATING PROJECTION ON THE SAID HELMET WHEREBY THE SAID VISOR CAN BE LOCKED IN THE LOWER CLOSED POSITION, THE SAID SPRING MEANS BEING ANCHORED AT EACH END AT POINTS SO LOCATED IN RELATION TO THE SAID VISOR PIVOT POINT AND THE SAID LEVER PIVOT POINT AS TO CONSTITUTE TO A TWO STAGE OVER-CENTER MECHANISM, OPERATION THROUGH THE FIRST STAGE OF THE SAID MECHANISM BEING BROUGHT ABOUT BY MANUAL LOWERING OF THE SAID VISOR INTO THE CLOSED POSITION DURING WHICH THE LINE OF ACTION OF THE SAID SPRING MEANS IS TRANSFERRED FROM ONE SIDE TO THE OTHER SIDE OF THE SIDE VISOR PIVOT POINT THUS BIASSING THE SAID VISOR INTO THE CLOSED POSITION, THE EFFECT OF A SUBSEQUENT G-FORCE EQUIVALENT TO THAT WHICH MIGHT BE EXPERIENCED BY A WEARER OF THE SAID HELMET ON BEING EJECTED FROM AN AIRCRAFT BY AN EJECTION SEAT BEING TO CAUSE OPERATION THROUGH THE SECOND STAGE OF THE SAID MECHANISM, THE SAID LEVER PIVOTING SO THAT THE LINE OF ACTION OF THE SAID SPRING MEANS IS TRANSFERRED FROM ONE SIDE TO THE OTHER SIDE OF THE SAID LEVER PIVOT POINT WITH THE RESULT THAT THE SAID LEVER BECOMES BIASSED INTO A POSITION WHICH RESULTS IN OPERATIONS OF THE SAID LOCKING MEANS TO LOCK THE SAID VISOR IN THE LOWER CLOSED POSITION.