Hydraulic baffle for waterbed mattress

Claim 1

In a waterbed mattress comprising a top sheet and a bottom sheet joined together to form a sealed envelope filled with liquid, the improvement comprising a damping structure floating freely within the envelope to dampen wave action in the mattress, the damping structure comprising: a bottom panel of flexible sheet material extending over substantially the entirety of the upper surface of the bottom sheet, a plurality of vertically disposed tubular structures coupled to the bottom panel to each extend independently upwardly therefrom, said tubular structures having free floating and independent top ends which are not interconnected, the tubular structures distributed over the bottom panel, the cumulative volume of the tubular structures comprising a substantial amount of the total volume of the envelope, each tubular structure having side walls of flexible material and a substantially horizontal top panel with the side walls coupled to the bottom panel to close a bottom end of the tubular structure and with the side walls coupled to the top panel to close a top end of the tubular structure, the top panel, bottom end and side walls of each tubular structure having, respectively, top port means, bottom port means, and side port means therethrough to permit relatively free liquid flow into and out of the tubular structure, each top panel comprising a thin plate of low density floatation means to float the top end of the tubular structure upwardly into engagement with the undersurface of the top sheet and restrict liquid flow through the top port means, the tubular structures being of a height that: (a) when the mattress is uncompressed, the bottom panel hangs downwardly from the top panels with the bottom panel spaced from the uppersurface of the bottom sheet, and (b) when the mattress is compressed, the bottom panel engages the uppersurface of the bottom sheet restricting liquid flow through the bottom port means.