Bi-surface sealing mechanism with rolling/sliding O-ring

Claim 1

In combination with a piston having a cylindrical outer wall, having an imaginary centerline parallel to said cylindrical outer wall, and moving in a direction of travel parallel to said centerline, and a stationary cylinder wall concentric and adjacent to said cylindrical outer wall of said piston, (a) a circumferential groove formed in one of said concentric walls and including (i) a floor having serrations formed therein, (ii) a pair of upstanding generally opposed elongate curved walls, the shortest distance across said groove between said opposed wall thereof being generally constant along the length of said circumferential groove, and (b) an endless annular elastic hose generally having, prior to being compressed in said groove, (i) a constant circular cross-sectional area along the length thereof, and (ii) a smooth continuous cylindrical surface area, said annular elastic hose being positioned in said circumferential groove against one of said opposed walls of said groove and compressed between (c) said serrated floor of said groove, and (d) a second surface formed integrally on one of said concentric walls, said shortest distance across said groove being such that during movement of said piston in said direction of travel parallel to said centerline, said hose (e) rolls away from one of said opposed walls of said groove and between said floor of said groove and said second surface toward said other of said pair of opposed walls of said groove, (f) rolls to a position against said other of said pair of opposed walls of said groove, and (g) maintains (i) said position against said other of said pair of opposed walls of said groove, and (ii) sliding contact with said second surface formed integrally on one of said concentric walls, while said piston continues to move in said direction parallel to said piston centerline, said serrations maintaining said hose in generally fixed position against said other of said pair of opposed walls of said groove while said piston continues to move in said direction of travel and causing said hose to roll at a generally equivalent rate along the length thereof from said one of said pair of opposed walls of said groove to said other of said pair of opposed walls of said groove.