Method of assembly of two metallic parts

Claim 1

A method of assembly of two tubular parts, the first part being formed of a hard metal the second part being formed of a malleable metal, the two tubular parts having a common axis of assembly, said method comprising the steps of (1) machining the end portion of said first part to reduce the external diameter of the end portion of said first part over a given length, designated as the assembly length, said first part end portion being machined along the assembly length in such a manner that the assembly length is a surface of revolution about the axis of the said first part, said surface of revolution including a groove at the portion of the assembly length most remote from the end of the first tubular part which carries said surface of revolution, said groove having a first conical surface at an angle α to the axis of the said first tubular part, said groove having a second conical surface at an angle β to the axis of said first tubular part, the said first and second conical surfaces being joined at corresponding ends thereof by a curved, beaded segment, designated as a toric surface, the said first conical surface opening to the original external surface of the said first tubular part, the said second conical surface opening to said portion of reduced diameter of the first tubular part, said assembly length also having at least one reversed conical surface groove of revolution axially spaced from said first mentioned groove, said reversed conical surface groove having one surface perpendicular to the axis of the first tubular part and having its other surface in the form of a conical surface which is opposite in direction, with respect to the axis of the first tubular part, to the conical surfaces in the first mentioned groove and (2) forcing an end of the second tubular part against the first tubular part end having said reduced external diameter, in a coaxial direction, to thereby deform the second tubular part end into said first mentioned groove on the first tubular part, and to thereby deform a portion of the second tubular part into said conical surface groove of revolution, the said end of the second tubular part completely filling the volume of material removed by machining from the said end of the first tubular part, the external and internal diameters of the first and second tubular parts, after said forcing step, being the same.

Claim 2

A method of assembly of two tubular parts, the first part being formed of a hard metal the second part being formed of a malleable metal, the two tubular parts having a common axis of assembly, said method comprising the steps of (1) machining the end portion of said first part to reduce the external diameter of the end portion of said first part over a given length, designated as the assembly length, said first part end portion being machined along the assembly length in such a manner that the assembly length is a surface of revolution about the axis of the said first part, said surface of revolution including a groove at the portion of the assembly length most remote from the end of the first tubular part which carries said surface of revolution, said groove having a first conical surface at an angle α to the axis of the said first tubular part, said groove having a second conical surface at an angle β to the axis of said first tubular part, the said first and second conical surfaces being joined at corresponding ends thereof by a curved, beaded segment, designated as a toric surface, the said first conical surface opening to the original external surface of the said first tubular part, the said second conical surface opening to said portion of reduced diameter of the first tubular part, said assembly length also having at least one reversed conical surface groove of revolution axially spaced from said first mentioned groove, said reversed conical surface groove having one surface perpendicular to the axis of the first tubular part and having its other surface in the form of a conical surface which is opposite in direction, with respect to the axis of the first tubular part, to the conical surfaces in the first mentioned groove and (2) forcing an end of the second tubular part against the first tubular part end having said reduced external diameter, in a coaxial direction, to thereby deform the second tubular part end into said first mentioned groove on the first tubular part, and to thereby deform a portion of the second tubular part into said conical surface groove of revolution, the said end of the second tubular part completely filling the volume of material removed by machining from the said end of the first tubular part, the external and internal diameters of the first and second tubular parts, after said forcing step, being the same.