1
David T Davis, Edward A Gilchrest Jr, Matthew L Prancuk: Pneumatic lift with unidirectional valve. Woodlark Circle, Duane Morris, April 9, 2013: US08413277 (8 worldwide citation)

A pneumatic lift including inflatable mattresses stacked one atop another and arranged in air flow communication with one another, but with each being independently deflatable.


2
David T Davis, Edward A Gilchrest JR, Matthew L Prancuk: Pneumatic Lift With Unidirectional Valve. Woodlark Circle, April 14, 2011: US20110083280-A1

A pneumatic lift including inflatable mattresses stacked one atop another and arranged in air flow communication with one another, but with each being independently deflatable.


3
Pneumatic lift with unidirectional valve. Woodlark Circle, August 8, 2013: US20130198964-A1

A pneumatic lift including inflatable mattresses stacked one atop another and arranged in air flow communication with one another, but with each being independently deflatable.