Axially locked pipe joint

Claim 1

In a pipe joint which includes relatively telescoping, substantially cylindrical bell and spigot members and an annular, resilient sealing gasket carried in said bell member and elastically embracing said spigot member and providing a fulcrum for limited angular deflection of said members; that improvement which comprises: a. an annular bearing ring carried circumferentially on said spigot member and defining thereon a radial enlargement disposed in axially outwardly spaced relation to said bell member, said bearing ring being formed with an outer, arcuately convex bearing surface; b. an annular locking collar carried for limited, universal pivoting movement on said bearing ring and having an inner diameter greater than the outer diameter of said spigot member, but less than the outer diameter of said bearing ring, said locking collar being formed with an inner, arcuately concave bearing surface engaging the arcuately convex bearing surface of said bearing ring and having a center of curvature disposed approximately at the center of a radial plane passing through the medial portion of said gasket; the radius of curvature of the concave bearing surface of said locking collar being cooperatively greater than the radius of curvature of the convex bearing surface of said bearing ring whereby to provide a full circle line of contact between said bearing ring and said locking collar throughout the full range of angular deflection of said bell and spigot members; and c. means detachably connecting said locking collar with said bell member and preventing accidental axial separation thereof.