CPC A63B 21/0088 (2013.01) [A63B 21/00181 (2013.01); A63B 21/4009 (2015.10); A63B 22/02 (2013.01); A63B 2208/053 (2013.01); A63B 2225/093 (2013.01)] | 14 Claims |
1. A differential air pressure (DAP) exercise system comprising an inflatable enclosure having a base portion secured to a DAP platform and a collapsible chamber connected to the base portion, the collapsible chamber comprising:
a pair of opposing substantially inelastic flexible sheets, each sheet having a base region attached to the inflatable enclosure base portion and a perimeter portion extending upward from the base region, each base region attached to the inflatable enclosure base portion at an opposite lateral side of the DAP platform from each other, each perimeter portion defining a chamber profile shape corresponding with a lateral profile of the chamber in an inflated, uncollapsed state, each perimeter portion comprising a top region, a front region, and a rear region; and
a seam securely attaching the pair of flexible sheets to each other along the corresponding perimeter portions at the corresponding top, front and rear regions;
wherein, in the inflated state:
inner regions of each of the flexible sheets expand apart under pressure and define an enclosure inner space therebetween;
the flexible sheets each transmit outboard forces from the pressure to the seam, the outboard forces applied at the seam from opposite transverse directions in a counterbalanced arrangement; and
application of the outboard forces through each sheet to the seam define a curved, low hoop stress edge portion along the enclosure at the corresponding top, front and rear regions when inflated.
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