Coupling fitting for connecting two parts

Claim 2

In the fluid-tight, tension, compression and torsion resisting joining of the end portions of a pair of fluid carrying tubes, the improvement with the tube end portions to be joined having exterior cylindrical surfaces; of a single one-piece sleeve in faying contact with and connecting said tube end portions in which said sleeve is formed with an initial inner surface from end to end substantially matching said cylindrical exterior surfaces on said tube end portions and an initial outer surface formed with a plurality of radially thickened and circumferentially directed gripping bands disposed in axial spaced relation along the length of said sleeve to be radially opposite to the tube end portions within said sleeve; said sleeve and tube end portions being formed of material yieldable to external pressure applied upon said sleeve, whereby said gripping bands on said sleeve are substantially completely transposed into said tube end portions to shape said tube end portions thereto and effect the fluid-tight, tension, compression and torsion resisting joining thereof, said initial outer surface of said sleeve being thereby altered to a uniform cylindrical form from end to end, the material of said sleeve being sufficiently rigid to retain the deformation and transposition of said gripping bands from the exterior surface thereof to said tube end portions, and said tube end portion being formed of material having a greater springback than that of said sleeve material to maintain outward hoop stress on said sleeve.

Claim 3

The improvement of claim 1 in which means is disposed between said sleeve and tube ends in faying contact to increase the resistance to leakage, tension and torsion stress.

Claim 4

The improvement of claim 2 wherein said stress increasing means is carried by said tube end portions.

Claim 5

The improvement of claim 2 wherein said sealing and stress increasing means is carried by said sleeve and includes a series of annular rings having inner surfaces engaging said tube end portions.

Claim 6

The improvement of claim 4 wherein said annular rings are formed of a material different from the material of said sleeve.

Claim 7

In a coupling assembly including a pair of pressure fluid carrying tubes to be connected for resisting tension, compression and torsion stresses, the improvement with the tubes to be joined having end portions formed initially with exterior cylindrical surfaces; of a single one-piece coupling sleeve in faying contact witH and connecting said tube end portions in which said coupling sleeve is formed with an initial inner surface substantially matching said cylindrical exterior surfaces on said tube end portions and an initial outer surface formed with a plurality of radially thickened and circumferentially directed gripping bands disposed in axial spaced relation along the length of said sleeve with at least one thickened gripping band aligned opposite each of said tube end portions within said sleeve; said coupling sleeve being formed of material yieldable to external pressure applied upon said sleeve to substantially completely transpose said gripping bands into said tube end portions, and said tube end portions being formed of material yieldable to external pressure from said gripping bands and having a greater springback than that of said coupling sleeve, whereby on connecting said tube end portions with said coupling sleeve the initial radially thickened outer surface of said coupling sleeve is altered to a uniform cylindrical form and said gripping bands are radially imprinted into said tube end portions to the configuration of said inwardly transposed gripping bands, the material of said coupling sleeve being sufficiently rigid to retain the deformation and transposition of said gripping bands from the exterior surface thereof to said tube end portions.

Claim 8

In a coupling assembly including a pair of pressure fluid carrying tubes to be connected for resisting tension, compression and torsion stresses, the improvement with the tubes to be joined having end portions formed initially with exterior cylindrical surfaces; of a single one-piece coupling sleeve in faying contact witH and connecting said tube end portions in which said coupling sleeve is formed with an initial inner surface substantially matching said cylindrical exterior surfaces on said tube end portions and an initial outer surface formed with a plurality of radially thickened and circumferentially directed gripping bands disposed in axial spaced relation along the length of said sleeve with at least one thickened gripping band aligned opposite each of said tube end portions within said sleeve; said coupling sleeve being formed of material yieldable to external pressure applied upon said sleeve to substantially completely transpose said gripping bands into said tube end portions, and said tube end portions being formed of material yieldable to external pressure from said gripping bands and having a greater springback than that of said coupling sleeve, whereby on connecting said tube end portions with said coupling sleeve the initial radially thickened outer surface of said coupling sleeve is altered to a uniform cylindrical form and said gripping bands are radially imprinted into said tube end portions to the configuration of said inwardly transposed gripping bands, the material of said coupling sleeve being sufficiently rigid to retain the deformation and transposition of said gripping bands from the exterior surface thereof to said tube end portions.

Claim 9

The improvement in the coupling assembly set forth in claim 6 wherein said radially thickened and circumferentially directed gripping bands vary in radial thickness about the circumference, whereby said sleeve and tube end portions are resistant to torsional stress.

Claim 10

The improvement in the coupling assembly set forth in claim 6 wherein said sleeve is initially exteriorly axially convergently tapered toward its opposite end portions whereby upon transposition of its said gripping bands inwardly said tapered end portions are transposed to form end portions having axially divergent tapered internal surfaces adjacent said tubes, and a film of protective material is disposed between said tube end portions and said axially divergent tapered surfaces in said sleeve.

Claim 11

The improvement in the coupling assembly set forth in claim 6 wherein said plurality of gripping bands includes at least one gripping band aligned with each tube end portion that varies in radial thickness as the band extends circumferentially of said sleeve to provide for torsional resistance, and includes at least one other gripping band aligned with each portion that has a substantially uniform radial thickness as the band extends circumferentially of said sleeve.