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Claim 1

IN A GAUGE OF THE CHARACTER DESCRIBED HAVING A CENTRAL CAVITY THEREIN CLOSED AT ONE END BY A HEAD PORTION HAVING A SUCTION INLET OPENING THEREIN COMMUNICATING WITH SAID CAVITY, THE COMBINATION OF AN AIR INPERVIOUS LINER WITHIN SAID CAVITY AND HAVING ONE END OF THE LINER SEALED AGAINST SAID HEAD PORTION AND ENCIRCLING SAID SUCTION INLET OPENING, A HOLLOW CUP DISPOSED WITHIN SAID LINER FOR MOVEMENT LONGITUDINALLY THEREOF AND HAVING CONVERGING SIDE WALLS CONNECTED BY A TRANSVERSE BOTTOM WALL, A COLLAPSIBLE DIAPHRAGM DISPOSED WITHIN SAID LINER IN SPACED RELATION TO SAID HEAD PORTION FOR RECEIVING SAID MOVABLE CUP MEMBER, SAID DIAPHRAGM HAVING FREELY FLEXIBALE INNER CONVERGING SIDE WALLS ENCLOSING SAID ALIGNED WITH SAID CUP CONVERGING SIDE WALLS AND TERMINATING AT ONE END IN AN ATTACHMENT TO SAID CUP BOTTOM WALL, OUTER SEMI-RIGID DIAPHRAGM SIDE WALLS DISPOSED ADJACENT SAID LINER AND TERMINATING IN FLANGES EXTENDING BENEATH THE OPEN PERIPHERY OF THE ADJACENT END OF SAID LINER FOR SEALING SAID END OPENING, THE ADJACENT UPPER END OF SAID OUTER DIAPHRAGM WALLS HAVING AN INWARDLY CURVED PORTION FORMING A CONTINUATION OF THE ADJACENT ENDS OF SAID INNER DIAPHRAGM WALLS, AND COIL SPRING MEANS DISPOSED BETWEEN SAID ABUTTING SAID HEAD PORTION AND SAID CUP BOTTOM WALL WITHIN SAID CUP SIDE WALLS.