Air cushion device with series resonator chamber

Claim 1

AN AIR CUSHION DEVICE COMPRISING A PAIR OF SHELL MEMBERS HAVING CIRCULAR HORIZONTAL WALLS BOUNDED BY VERTICALLY OPPOSITELY EXTENDING CYLINDRICAL WALLS DISPOSED IN TELESCOPED RELATION FORMING A FIXED CROSS SECTION RESONATOR CHAMBER VERTICALLY THEREBETWEEN AND AN ANNULAR RECESS RADIALLY THEREBETWEEN, A PREFORMED FLEXIBLE MEMBRANE HAVING A DISHED LOWER WALL PORTION SECURED CENTRALLY THEREOF TO ONE OF SAID MEMBER AND AN OUTER CYLINDRICAL WALL PORTION DISPOSED IN SAID RECESS AND RE-ENTRANTLY FOLDED ABOUT A CIRCUMFERENTIAL BEAD, SAID BEAD HAVING A CROSS SECTIONAL DIAMETER GREATER THAN THE RADIAL DIMENSION OF SAID RECESS, MEANS FOR INTRODUCING AIR UNDER PRESSURE INTO SAID FIXED CROSS SECTION CHAMBER, MEANS PROVIDING RESTRICTED COMMUNICATION BETWEEN SAID FIXED CROSS SECTION CHAMBER AND SAID VARIABLE CROSS SECTION CHAMBER, AND MEANS FORMING A PLURALITY OF APERTURES IN SAID MEMBRANE ADJACENT THE CENTER THEREOF.