Coupling sleeve

Claim 1

A coupling sleeve for joining a first and a second conduit section, each of said conduit sections having two ends and a length equal to at least four times its external diameter, and having circular cylindrical outer wall surfaces with an axial passage of constant cross-sectional dimensions and configurations, one end of each of said conduit sections having a flat substantially perpendicular end face and external thread means thereon and the other end of each of said conduit sections being non-threaded and having a flat substantially perpendicular end face and a length of reduced outside diameter extending axially inwardly from said flat substantially perpendicular end face at said other end of said conduit section to form a stop shoulder in said outer wall surface at said non-threaded end, and a lock ring means positioned in a lock ring groove located in said outer wall surface near and spaced axially inwardly from said stop shoulder, said lock ring means in its normal unbiased condition projecting in part above said outer wall surface, said coupling sleeve comprising: (a) a body having an axially inward end with an end face and an axially outward end with an end face; (b) a first radially inwardly extending flange at said axially inward end; (c) a second radially inwardly extending flange adjacent said axially outward end, said second flange having female thread means thereon; (d) said first flange defining a central opening of a diameter slightly greater than the diameter of said outer wall surface; (e) said second flange defining a central opening smaller than the diameter of said outer wall surface, but slightly greater than the diameter of said length of reduced outside diameter, said central openings being in axial alignment so that said coupling sleeve may be slipped onto said other non-threaded end of said first conduit section; (f) an axial clearance formed between said first and second flanges having an axially extending wall; and (g) an annular undercut disposed between an axially outward face of said first flange and said wall of said axial clearance constructed and arranged to receive foreign material trapped between said axially outward face of said first flange and said lock ring means to ensure proper cooperation of said outward face with said lock ring means, (h) at least one of said lock ring means and a cooperating surface of said first flange having camming means to constrict said lock ring means into said annular lock ring groove when said coupling sleeve is moved axially inwardly on said non-threaded end of said first conduit section; (i) said axial clearance receiving said lock ring means when it returns to its normal unbiased position as said first flange clears said lock ring means; (j) said axially outward face of said first flange adapted to cooperate with said lock ring means to prevent said lock ring means from being forced radially inwardly entirely into said lock ring groove so that said coupling sleeve is prevented from being pulled axially outwardly from said other non-threaded end of said first conduit section as said coupling sleeve is threaded onto said one externally threaded end of said second conduit section so as to force said end faces of said first and second conduit sections together; (k) said length of reduced outside diameter extending axially inwardly at least the width of said second flange so that said coupling sleeve may be backed off said externally threaded end of said second conduit section after said first and second conduit sections are assembled whereby said second flange will abut said stop shoulder and said end face of said coupling sleeve will be at least flush with said flat substantially perpendicular end face of said first conduit section to permit said first conduit section to be laterally displaced from said second conduit section without longitudinal movement of either conduit section.