Mask for the protection against poison gases

Claim 1

IN A MASK ASSEMBLY, IN COMBINATION: (A) A FACE PIECE DEFINING A CAVITY THEREIN; (B) AN APPROXIAMTELY CUP-SHAPED MUZZLE MEMBER IN SAID CAVITY, (1) SAID FACE PIECE AND SAID MUZZLE MEMBER EACH HAVING A FRONT PORTION, A REAR PORTION, AND TWO OPPOSITE SIDE PORTIONS CONNECTING THE FRONT AND REAR PORTIONS, (2) SAID MUZZLE MEMBER DEFINING A REARWARDLY OPEN SPACE THEREIN AND SEPARATING A FRONT PART OF SAID CAVITY ADJACENT SAID FRONT PORTION OF THE FACE PIECE FROM A REARWARDLY OPEN REMAINDER OF SAID CAVITY, (3) THE FRONT PORTION OF SAID FACE PIECE BEING FORMED WITH AN APERTURE COMMUNICATING WITH SAID FRONT PART; (C) FASTENING MEANS SEALINGLY FASTENING SAID FRONT PORTIONS TO EACH OTHER IN ABUTTING ENGAGEMENT; (D) ATTACHING MEANS RELEASABLY ATTACHING SAID REAR PORTIONS TO EACH OTHER IN ABUTTING ENGAGEMENT; (E) EYEPIECE MEANS ON A PORTION OF SAID FACE PIECE IN CONTACT WITH SAID REMAINDER OF SAID CAVITY; (F) EACH SIDE PORTION OF SAID MUZZLE MEMBER DEFINING AN ELONGATED CONDUIT WITH A CORRESPONDING SIDE PORTION OF SAID FACE PIECE, SAID CONDUIT BEING LATERALLY CLOSED BY SAID ABUTTINGLY ENGAGED FRONT AND REAR PORTIONS, (1) SAID CONDUITS HAVING RESPECTIVE FIRST LONGITUDINAL END PORTIONS COMMUNICATING WITH SAID FRONT PART OF SAID CAVITY, AND LATERALLY SPACED RESPECTIVE SECOND END PORTIONS HAVING RESPECTIVE ORIFICES IN SAID REMAINDER OF SAID CAVITY FACING IN A PREDETERMINED DIRECTION TOWARD SAID EYEPIECE MEANS, (2) SAID MUZZLE MEMBER BEING FORMED WITH A PASSAGE THERETHROUGH LATERALLY SPACED FROM SAID ORIFICES IN OPPOSITE DIRECTIONS, SAID PASSAGE EXTENDING FROM SAID REMAINDER OF SAID CAVITY TO SAID SPACE IN A DIRECTION SUBSTANTIALLY OPPOSITE TO SAID PREDETERMINED DIRECTION; (G) ONE-WAY VALVE MEANS IN SAID PASSAGE, SAID VALVE MEANS BEING SELECTIVELY RESPONSIVE TO A PRESSURE IN SAID CAVITY HIGHER THAN THE PRESSURE IN SAID SPACE TO OPEN SAID PASSAGE; AND (H) EXHAUST MEANS FOR EXHAUSTING EXHALED AIR FROM SAID SPACE.