O-ring push-pull pipe joint

A push-pull pipe joint comprising:

• an outer pipe coupling member having an open end and comprising:
• a pair of tapered internal grooves near the open end of the coupling member wherein said pair comprises an inner groove further from the open end abutting an outer groove closer to the open end,
• a junction located between the grooves,
• wherein the diameter of the outer groove immediately adjacent said junction is larger than the diameter of the inner groove immediately adjacent said junction, forming a circumferential ridge between the grooves, and
• wherein the outer groove comprises a portion tapering toward a smaller diameter nearer the open end and a flat portion between the tapered portion and the ridge;
• an internal pipe to be joined, wherein the outside diameter of the pipe smaller than the inside diameter of the coupling member open end;
• and
• an O-ring gasket compressed between an inner surface of the coupling and an outer surface of the pipe,
• wherein the pipe rolls the compressed O-ring gasket along the inner groove and into the abutting outer groove, wherein the O-ring gasket is further rolled and is trapped by the tapered portion of the outer groove, thereby forming a joint between the pipe and the coupling end.

A method for joining a pipe and a coupling member having an open end and an outer tapered groove near the open end abutting an inner tapered groove, with a junction formed by a circumferential ridge located between said grooves wherein each groove has a flat section and a tapered section which tapers toward the open end, comprising the steps of:

• fitting an O-ring gasket into the flat section of the inner groove;
• sliding the pipe inside the end of the coupling member and engaging an inside annular surface of the O-ring gasket, compressing the O-ring gasket against an inner surface of the coupling;
• retracting the pipe from the coupling member to roll the O-ring gasket against the decreasing diameter taper of the inner groove;
• and
• further retracting the pipe until the entire O-ring gasket rolls past said circumferential ridge at the junction between the grooves and expands into the flat portion of the outer groove, wherein the O-ring gasket is restrained by the tapered portion of the outer groove.

A push-pull pipe joint comprising:

• an outer coupling member having an open end and comprising:
• a pair of tapered internal annular grooves near the open end comprising an inner groove further from the open end abutting an outer groove closer to the open end,
• wherein each inner groove has a tapering portion which tapers at a constant angle toward the adjacent outer groove, forming a conical section, and
• wherein each outer groove has a tapering portion which tapers at a constant angle toward the open end, decreasing the groove diameter to a diameter equal to the inside diameter of the open end the;
• diameter of said outer groove is greater than the diameter of said inner groove where said grooves are abutting
• an internal pipe to be joined to the outer coupling member, wherein the outside diameter of the pipe is slightly smaller than the inside diameter of the open end;
• and
• an O-ring gasket compressed between an inner surface of the coupling and an outer surface of the pipe,
• wherein the pipe rolls the compressed O-ring gasket along the inner groove tapering portion and into the abutting outer groove, wherein the O-ring gasket is further rolled and is trapped by the tapered portion of the outer groove, thereby forming a joint between the first pipe and the coupling end.