Pipe coupling

Claim 1

A coupling for connecting a cylindrical pipe end portion to the beaded end portion of a second pipe in axially aligned, noncontacting relation, said coupling including: a. an annular resilient liner, composed of a low-to-intermediate durometer hardness synthetic elastomeric material, surrounding said pipe end portions, said liner having a substantially cylindrical outer surface with an inwardly directed annular surface recess, said liner further having a profiled inner surface, said inner surface includng an inwardly projecting rib portion extending between said pipe ends with said rib portion being located in the area substantially radially inwardly from said liner external surface recess; a profiled first portion adjoining one side of said rib portion and substantially surrounding said beaded pipe end portion; a profiled second portion having a recessed section and a contoured section, with said recessed section adjoining the other side of said rib portion and substantially surrounding the annular end surface of said cylindrical pipe end portion and said contoured section substantially surrounding a first outer peripheral surface section of said cylindrical pipe end portion; and a cylindrical third portion, adjoining the contoured section of said profiled second portion and surrounding a second annular outer peripheral surface section of said circular pipe end portion; b. an annular, generally cylindrical, compliant layer of fluorofilm material interposed between said pipe end portions and the rib, first, and second portions of said liner inner surface for substantially the entire axial extent of said liner portions, said layer, which is in the range from 0.005 to 0.020 inches thick, reacting and yielding to conform to said pipe end portions in substantially the same manner as said liner; c. a force-development member, including a flexible generally cylindrical one piece clamp ring having a bridging strip for providing at least 360* of surroundment of said liner, said clamp ring also surrounding said resilient liner for the full axial extent of said liner, said clamp ring further including multiple semi-independent constriction means for constricting said clamp ring at least in the areas thereof generally overlying said liner first portion and said liner third portion, said multiple semi-independent constriction means allowing said clamp ring, if necessary, to develop a conical configuration to thereby adapt to a variety of outside diameters of pipe ends on one side of said coupling as necessary due to normal pipe manufacturing tolerances; and d. a compliant expander ring of high density plastic material interference-fitted into said recessed section of said liner profiled second portion and abutting the other side of said liner rib portion, said ring by reason of its interference fit, causing a slight radial expansion of the recessed section of said liner profiled second portion into said external surface recess in said liner outer surface, with said radial expansion also slightly increasing the diameter of the contoured section of said lIner profiled second portion and thereby preventing said cylindrical pipe end from damaging said liner second section during the insertion of said cylindrical pipe end, said ring, by reason of its compliancy, upon the constriction of said semi-independent constriction means overlying said liner third portion, allowing at least a part of said liner second portion to be displaced radially inwardly into circumferential contact with said cylindrical pipe end first outer peripheral surface section.