(under subclass 55) The spring encircling rigid annulus in the spring wheel is resiliently supported against radial motion relative to the wheel center by a chamber or chambers filled with fluid under pressure greater than atmospheric, whether under load or not, with the exception of ... indented hereunder, wherein the pressure may at times be
atmospheric or less.
SEE OR SEARCH THIS CLASS, SUBCLASS:
40+, for spring wheels with chambers having elastic walls wherein the pressure is atmospheric.
