Patent ID: 8444185

Claim:
A seal assembly for use sealing a gap between two opposing members of a joint assembly, the seal assembly comprising: an annular elastomeric seal comprising a central radially outer convex surface region and a central radially inner concave surface region, the central radially outer convex surface region terminating at each axial end with a radially outward extending lip, and the annular elastomeric seal being of an essentially uniform thickness in the circumferential direction between the central radially outer convex surface region and the central radially inner concave surface region; and an extrusion preventing ring disposed on a radial side of the annular elastomeric seal for radially supporting the annular elastomeric seal against extrusion past the extrusion preventing ring to preventing radial extrusion of the annular elastomeric seal through a gap disposed on a side of the extrusion preventing ring opposite the sealing member, the extrusion preventing ring comprising a continuous length of strip having opposing ends, the strip having sufficient axial stiffness or rigidity so as not to buckle or bend when subjected to a force applied to the interior or exterior surface of the ring, which strip is wound upon itself to form an innermost turn at least partially overlapped by an adjacent turn to define an overlap region by an amount that enables the ring to expand and contract radially without a circumferential gap forming between the opposing ends of the strip, and wherein the ring is configured to radially expand by decreasing the length of the overlap region as the force is applied to the interior surface of the ring and configured to radially and contract by increasing the length of the overlap region as the force is applied to the exterior surface of the ring.