Tip seal back-up member for use in fluid apparatus of the scroll type

Claim 1

A wrap element with tip seal and back-up member for use in fluid apparatus of the scroll type comprising a. a wrap element defining at least a first flank surface of generally spiroidal configuration about a reference axis, said flank surface extending generally in an axial direction and terminating in a tip surface lying in a plane substantially perpendicular to said reference axis; b,. a groove disposed within said tip surface of spiroidal configuration generally conforming to that of said flank surface, said groove including at least a radially outer lateral wall and a bottom wall; c. a tip seal disposed at least partially within said groove and extending longitudinally about the spiroidal configuration thereof; and d. a back-up member comprising a strip of material disposed within said groove between its bottom wall and said tip seal and extending longitudinally about the spiroidal configuration of the groove, said strip of material having a preformed configuration such that its radially inner edge portion engages the tip seal and is disposed axially toward the tip surface of said wrap element with respect to the radially outer edge portion thereof, which outer edge portion engages a wall of the groove, and said strip of material being constructed of an elastic material such that as said radially inner edge portion is displaced toward the bottom wall of the groove and relative to the radially outer edge portion, an opposing spring force is developed in order to provide a seal and prevent fluid from leaking under the tip seal.