Heavy duty tube coupling

Claim 1

A tube coupling consisting of only two pieces: a body and a threaded member; interengageable threads on said body and said threaded member; said body having an aperture for fluid under pressure; a unitary inner sleeve and a unitary outer sleeve on said body each substantially coaxially surrounding said aperture and defining a metal tube-receiving annular groove therebetween extending into said body from a first end thereof; said threaded member adapted to have an annular inner surface overlying said outer sleeve of said body and to have a first end adjacent said first end of said body in the assembled condition; an annular cam surface on the inner surface of said threaded member reducing in cross-sectional area toward said first end of said threaded member; an annular cam follower outer surface intermediate the longitudinal ends of said outer sleeve of said body reducing to a smaller diameter toward said first end of said body; said unitary inner sleeve having an outer end at said body first end and an intermediate annular area longitudinally intermediate said outer end and the bottom of said annular groove; and whereby with a tube in place in said annular groove the threaded member may be tightened on the body to have said cam surface and cam follower surface interact and the unitary outer sleeve crushed inwardly in an annular area intermediate the longitudinal ends thereof onto the outer surface of the tube and the tube and unitary inner sleeve crushed radially inwardly only in said intermediate annular area to form a fluid pressure-tight seal of at least several atmospheres between the body and the tube.

Claim 21

The method of obtaining a fluid-tight seal in a tube coupling having only a body and an interengaging threaded member, the body having unitary inner and outer sleeves defining an annular tube-receiving groove therebetween extending into a first end of the body, and an annular cam follower intermediate the ends of the outer sleeve engageable by a cam on the threaded member, said method comprising the steps of: inserting an end of a tube longitudinally into the annular groove until the end of the tube engages the bottom of the groove; and tightening the threaded member to engage the cam with the cam follower and causing the corresponding intermediate annular portion of the outer sleeve and only the intermediate annular portions of the inner sleeve and the tube to be compressed in a radially inward direction to make a fluidtight seal between the outer sleeve and the outer surface of the tube, with relative rotation between the cam and follower and an absence of rotation among the tube and inner and outer sleeves.

Claim 22

The method of obtaining a fluid-tight seal in a tube coupling having only a body and an interengaging threaded member, the body having unitary inner and outer sleeves defining an annular tube-receiving groove therebetween extending into a first end of the body, and an annular cam follower intermediate the ends of the outer sleeve engageable by a cam on the threaded member, said method comprising the steps of: inserting an end of a tube longitudinally into the annular groove until the end of the tube engages the bottom of the groove; and tightening the threaded member to engage the cam with the cam follower and causing the corresponding intermediate annular portion of the outer sleeve and only the intermediate annular portions of the inner sleeve and the tube to be compressed in a radially inward direction to make a fluidtight seal between the outer sleeve and the outer surface of the tube, with relative rotation between the cam and follower and an absence of rotation among the tube and inner and outer sleeves.