Tube coupling for large diameter tubes

Claim 2

A tube coupling comprising: a coupling body having a bore and a counterbore, said counterbore being substantially cylindrical throughout a portion of its length and being provided with a coaxial rearwardly opening, generally frusto-conical camming mouth; a tube stub having a bore, a first end defined by a substantially cylindrical exterior surface and a second end adapted to be secured to a tube; said tube stub having a ferrule defined by an outwardly expanded nose with an external surface having substantially the form of a right circular forwardly converging conical frustum, said external surface of said nose prior to make-up of the coupling, defining a half-angle with respect to the axis of the tube stub bore less than that defined by said camming mouth with respect to the axis of the coupling body bore, the forward end of said nose terminating with a curved apical zone seated against said camming mouth in initial nonpressure contact along a line of predetermined diameter, said curved apical zone being defined by a radius drawn from a center; said center being located substantially in the plane of said cylindrical external surface of said first end of said tube stub; said curved apical zone intersecting said cylindrical exterior surface of said first end of said tube stub; said ferrule further being provided with a back face; a coupling nut threadedly engaged with the body and provided with a coaxial internal thrust surface disposed in axially spaced opposition to the camming mouth and cooperable with said back face to advance said nose into said camming mouth in a wedging action sufficient to establish a seal upon make-up of the coupling.

Claim 3

The of claim 1 in which the difference in half-angles defined by said external surface of said nose and said camming mouth is in the range of about 2*to 3*.

Claim 4

A tube coupling comprising: a coupling body having a bore and a counterbore, said counterbore being substantially cylindrical throughout a portion of its length and being provided with a coaxial rearwardly opening, generally frusto-conical camming mouth; a tube stub having a bore, a first end defined by a substantially cylindrical exterior surface and a second end adapted to be secured to a tube; said tube stub having a ferrule defined by an outwardly expanded nose with an external surface having substantially the form of a right circular forwardly converging conical frustum, said external surface of said nose prior to make-up of the coupling, defining a half-angle with respect to the axis of the tube stub bore less than that defined by said camming mouth with respect to the axis of the coupling body bore, the difference in half-angles defined by said external surface of said nose and said camming mouth being in the range of 2* to 3*, the forward end of said nose terminating with a curved apical zone seated against said camming mouth in initial nonpressure contact along a line of predetermined diameter, said curved apical zone being defined by a radius drawn from a center; said ferrule further being provided with a back face; a coupling nut threadedly engaged with the body and provided with a coaxial internal thrust surface disposed in axially spaced opposition to the camming mouth and cooperable with said back face to advance said nose into said camming mouth in a wedging action sufficient to establish a seal upon make-up of the coupling.

Claim 5

A tube coupling comprising: a coupling body having a bore and a counterbore, said counterbore being substantially cylindrical throughout a portion of its length and being provided with a coaxial rearwardly opening, generally frusto-conical camming mouth; a tube stub having a bore, a first end defined by a substantially cylindrical exterior surface and a second end adapted to be secured to a tube; said tube stub having a ferrule defined by an outwardly expanded nose with an external surface having substantially the form of a right circular forwardly converging conical frustum, said external surface of said nose prior to make-up of the coupling, defining a half-angle with respect to the axis of the tube stub bore less than that defined by said camming mouth with respect to the axis of the coupling body bore, the difference in half-angles defined by said external surface of said nose and said camming mouth being in the range of 2* to 3*, the forward end of said nose terminating with a curved apical zone seated against said camming mouth in initial nonpressure contact along a line of predetermined diameter, said curved apical zone being defined by a radius drawn from a center; said ferrule further being provided with a back face; a coupling nut threadedly engaged with the body and provided with a coaxial internal thrust surface disposed in axially spaced opposition to the camming mouth and cooperable with said back face to advance said nose into said camming mouth in a wedging action sufficient to establish a seal upon make-up of the coupling.

Claim 6

The invention of claim 3 in which said center is located substantially in the plane of said cylindrical exterior surface of said first end of said tube stub.

Claim 7

A tube coupling comprising: a coupling body having a bore and a counterbore, said counterbore being substantially cylindrical throughout a portion of its length and being provided with a coaxial rearwardly opening, generally frusto-conical camming mouth; a tube stub having a bore, a first end defined by a substantially cylindrical exterior surface and a second end adapted to be secured to a tube; said tube stub having a ferrule defined by an outwardly expanded nose with an external surface having substantially the form of a right circular forwardly converging conical frustum, said external surface of said nose prior to make-up of the coupling, defining a half-angle with respect to the axis of the tube stub bore less than that defined by said camming mouth with respect to the axis of the coupling body bore, the forward end of said nose terminating with a curved apical zone seated against said camming mouth in initial nonpressure contact along a line of predetermined diameter, said curved apical zone being defined by a radius drawn from a center, said center being located in the plane of said cylindrical exterior surface of said first end of said tube stub; said ferrule further being provided with a back face; a coupling nut threadedly engaged with the body and provided with a coaxial internal thrust surface disposed in axially spaced opposition to the camming mouth and cooperable with said back face to advance said nose into said camming mouth in a wedging action sufficient to establish a seal upon make-up of the coupling.

Claim 8

A tube coupling comprising: a coupling body having a bore and a counterbore, said counterbore being substantially cylindrical throughout a portion of its length and being provided with a coaxial rearwardly opening, generally frusto-conical camming mouth; a tube stub having a bore, a first end defined by a substantially cylindrical exterior surface and a second end adapted to be secured to a tube; said tube stub having a ferrule defined by an outwardly expanded nose with an external surface having substantially the form of a right circular forwardly converging conical frustum, said external surface of said nose prior to make-up of the coupling, defining a half-angle with respect to the axis of the tube stub bore less than that defined by said camming mouth with respect to the axis of the coupling body bore, the forward end of said nose terminating with a curved apical zone seated against said camming mouth in initial nonpressure contact along a line of predetermined diameter, said curved apical zone being defined by a radius drawn from a center, said center being located in the plane of said cylindrical exterior surface of said first end of said tube stub; said ferrule further being provided with a back face; a coupling nut threadedly engaged with the body and provided with a coaxial internal thrust surface disposed in axially spaced opposition to the camming mouth and cooperable with said back face to advance said nose into said camming mouth in a wedging action sufficient to establish a seal upon make-up of the coupling.

Claim 9

The invention of claim 5 in which the difference in half-angles defined by said external surface of said nose and said camming mouth is in the range of about 2* to 3*.

Claim 10

The invention of claim 5 in which said thrust surface is defined as a rearwardly converging generally frusto-conical surface.

Claim 11

The invention of claim 5 in which said thrust surface contacts said back face upon make-up of the coupling.

Claim 12

The invention of claim 5 in which a slip ring is disposed between said thrust surface and said back face.

Claim 13

The invention of claim 5 in which said ferrule is integral with said tube stub.

Claim 14

The invention of claim 5 in which said ferrule is provided with a body and said back face is defined on said body.

Claim 15

The invention of claim 11 in which said body includes a generally cylindrical surface having an axis parallel to the axis of said tube stub and said coupling nut is provided with an internal generally cylindrical surface disposed closely adjacent said surface of said body.

Claim 16

A tube coupling comprising: a coupling body having a bore and a couNterbore, said counterbore being substantially cylindrical throughout a portion of its length and being provided with a coaxial rearwardly opening, generally frusto-conical camming mouth; a tube stub having a bore, a first end defined by a substantially cylindrical exterior surface and a second end adapted to be secured to a tube; said tube stub having a ferrule defined by an outwardly expanded nose with an external surface having substantially the form of a right circular forwardly converging conical frustum, said external surface of said nose prior to make-up of the coupling, defining a half-angle with respect to the axis of the tube stub bore less than that defined by said camming mouth with respect to the axis of the coupling body bore, the forward end of said nose terminating with a curved apical zone seated against said camming mouth in initial nonpressure contact along a line of predetermined diameter, said curved apical zone being defined by a radius drawn from a center; a counterbore provided in said tube stub at said first end, said counterbore extending into said tube stub a distance sufficient to reduce the wall thickness of said tube stub in the area of contact of said nose and said camming mouth; said ferrule further being provided with a back face; a coupling nut threadedly engaged with the body and provided with a coaxial internal thrust surface disposed in axially spaced opposition to the camming mouth and cooperable with said back face to advance said nose into said camming mouth in a wedging action sufficient to establish a seal upon make-up of the coupling.

Claim 17

A tube coupling comprising: a coupling body having a bore and a couNterbore, said counterbore being substantially cylindrical throughout a portion of its length and being provided with a coaxial rearwardly opening, generally frusto-conical camming mouth; a tube stub having a bore, a first end defined by a substantially cylindrical exterior surface and a second end adapted to be secured to a tube; said tube stub having a ferrule defined by an outwardly expanded nose with an external surface having substantially the form of a right circular forwardly converging conical frustum, said external surface of said nose prior to make-up of the coupling, defining a half-angle with respect to the axis of the tube stub bore less than that defined by said camming mouth with respect to the axis of the coupling body bore, the forward end of said nose terminating with a curved apical zone seated against said camming mouth in initial nonpressure contact along a line of predetermined diameter, said curved apical zone being defined by a radius drawn from a center; a counterbore provided in said tube stub at said first end, said counterbore extending into said tube stub a distance sufficient to reduce the wall thickness of said tube stub in the area of contact of said nose and said camming mouth; said ferrule further being provided with a back face; a coupling nut threadedly engaged with the body and provided with a coaxial internal thrust surface disposed in axially spaced opposition to the camming mouth and cooperable with said back face to advance said nose into said camming mouth in a wedging action sufficient to establish a seal upon make-up of the coupling.