High-strength joint and fastener assembly therefor

Claim 2

In a high-strength joint comprising at least two structural members with substantially aligned bores therein, a sleeve of relatively hard material having a limited ductility, said sleeve having a cylindrical exterior surface and a tapered internal surface and extending throughout the length of said aligned bores, a bolt having a driving head and a shank, said shank including a tapered segment having a taper complimentary to said sleeve internal taper and a threaded end portion, a threaded fastener member adapted to coact with said bolt threaded end portion, the improvement wherein: said sleeve includes a single longitudinally disposed expandable joint extending throughout the longitudinal extent of said sleeve to allow said sleeve to expand radially outwardly within the confines of said aligned bores in said structural members when said joint is loaded thereby to impart a uniform stress to the wall surfaces defining said bores, said expandable joint comprising a scarfed step joint wherein a potion of said sleeve overlaps another portion of said sleeve in face-to-face abutting relationship.

Claim 3

In a high-strength joint comprising at least two structural members with substantially aligned bores therein, a sleeve having a cylindrical exterior surface and a tapered internal Surface within said aligned bores, a bolt having a driving head and a shank, said shank including a tapered segment having a taper complimentary to said sleeve internal taper and a threaded end portion, a threaded fastener member adapted to coact with said bolt threaded end portion, the improvement wherein: said sleeve includes a single longitudinally disposed expandable joint to allow said sleeve to expand radially outwardly within the confines of said aligned bores in said structural members when said joint is loaded thereby to impart a uniform stress to the wall surfaces defining said bores, said expandable joint comprising a scarfed step joint wherein a portion of said sleeve overlaps another portion of said sleeve in face-to-face abutting relationship, said overlapping portions of said joint comprising arcuate finger extensions of said sleeve, each said extension being of the order of one-half the thickness of the sleeve and having a radius of curvature coincident with the radius of curvature of said sleeve at that point.

Claim 4

In a high-strength joint comprising at least two structural members with substantially aligned bores therein, a sleeve having a cylindrical exterior surface and a tapered internal Surface within said aligned bores, a bolt having a driving head and a shank, said shank including a tapered segment having a taper complimentary to said sleeve internal taper and a threaded end portion, a threaded fastener member adapted to coact with said bolt threaded end portion, the improvement wherein: said sleeve includes a single longitudinally disposed expandable joint to allow said sleeve to expand radially outwardly within the confines of said aligned bores in said structural members when said joint is loaded thereby to impart a uniform stress to the wall surfaces defining said bores, said expandable joint comprising a scarfed step joint wherein a portion of said sleeve overlaps another portion of said sleeve in face-to-face abutting relationship, said overlapping portions of said joint comprising arcuate finger extensions of said sleeve, each said extension being of the order of one-half the thickness of the sleeve and having a radius of curvature coincident with the radius of curvature of said sleeve at that point.

Claim 5

A fastener assembly for a high-strength joint comprising a bolt having a driving head, a shank threaded at its end, said shank including a tapered midportion having a generally frustoconical configuration with the wider end adjacent said driving head and the narrower end adjacent said threaded end, an internally threaded nut adapted to engage and coact with said threaded end, and a sleeve member of relatively hard material having a limited ductility, said sleeve having a generally cylindrical exterior and a frustoconical internal surface complimentary to the frustoconical portion of said bolt shank, said sleeve extending longitudinally throughout the frustoconical portion of said bolt shank and further including a longitudinally disposed expandable joint extending throughout the longitudinal extent of said sleeve thereby to permit a uniform radially outward expansion of said sleeve when said nut is progressively engaged on said bolt while said bolt is positioned within said sleeve, said expandable joint comprising overlapped arcuate extensions of the wall of said sleeve.

Claim 6

A fastener assembly for a high-strength joint comprising a bolt having a driving head, a shank threaded at its end, said shank including a tapered midportion having a generally frustoconical configuration with the wider end adjacent said driving head and the narrower end adjacent said threaded end, an internally threaded nut adapted to engage and coact with said threaded end, and a sleeve member of relatively hard material having a limited ductility, said sleeve having a generally cylindrical exterior and a frustoconical internal surface complimentary to the frustoconical portion of said bolt shank, said sleeve extending longitudinally throughout the frustoconical portion of said bolt shank and further including a longitudinally disposed expandable joint extending throughout the longitudinal extent of said sleeve thereby to permit a uniform radially outward expansion of said sleeve when said nut is progressively engaged on said bolt while said bolt is positioned within said sleeve, said expandable joint comprising overlapped arcuate extensions of the wall of said sleeve.

Claim 7

A fastener assembly for a high-strength joint comprising a blot having a driving head, a shank threaded at its end, said shank including a tapered midportion having a generally frustoconical configuration with the wider end adjacent said driving head and the narrower end adjacent said threaded end, an internally threaded nut adapted to engage and coact with said threaded end, and a sleeve member having a generally cylindrical exterior and a frustoconical internal surface complimentary to the frustoconical portion of said bolt shank, said sleeve further including a single longitudinally disposed expandable joint thereby to permit a uniform radially outward expansion of said sleeve when said nut is progressively engaged on said bolt while said bolt is positioned within said sleeve, said expandable joint comprising overlapped arcuate extensions of the wall of said sleeve, each said arcuate extension having a thickness approximately equal to one-half the wall width of the sleeve.

Claim 8

A fastener assembly for a high-strength joint comprising a blot having a driving head, a shank threaded at its end, said shank including a tapered midportion having a generally frustoconical configuration with the wider end adjacent said driving head and the narrower end adjacent said threaded end, an internally threaded nut adapted to engage and coact with said threaded end, and a sleeve member having a generally cylindrical exterior and a frustoconical internal surface complimentary to the frustoconical portion of said bolt shank, said sleeve further including a single longitudinally disposed expandable joint thereby to permit a uniform radially outward expansion of said sleeve when said nut is progressively engaged on said bolt while said bolt is positioned within said sleeve, said expandable joint comprising overlapped arcuate extensions of the wall of said sleeve, each said arcuate extension having a thickness approximately equal to one-half the wall width of the sleeve.