Expandable fastener and locking means therefor

An expandable fastener assembly for use in locking relationship with an interiorly threaded member comprising

• a screw body having an expandable, exteriorly threaded section, said body defining a cavity extending therethrough which is co-axial with a longitudinal axis thereof, said cavity including a cylindrically shaped first segment extending from a first opening on a first end of said body to a position in a central region of said body, and a frusto-conically shaped second segment communicating with said first segment and extending at a first predetermined constant rate of taper to a second opening on a second end of said body, and
• an elongated spindle having a cylindrically shaped first end portion adapted for relatively close fitting slidable engagement with said first segment, and a second portion forming a frusto-conically shaped boss extending from connection with said first end portion at a second predetermined constant rate of taper, said boss being insertable by it's smaller end into said second opening and segment to radially expand said threaded section to lock said body in an interiorly threaded member, said screw body comprising a bolt which includes said exteriorly threaded section and a bolthead integrally attached to one end of said section, said first opening being on said bolthead, said bolthead defining a first circular recess disposed eccentrically within a second circular recess, said first opening being centered on a base of said first recess, said first recess being sized to retain a threaded fastener therein while being rotatably adjusted on a threaded end portion of said first spindle segment which projects out of said cavity through said first opening, said second recess being sized to retain a circular split locking ring therein when said ring is disposed about said threaded fastener and said threaded fastener is disposed in said first recess such that opposing ends of said ring bind between said threaded fastener and a peripheral wall of said second recess as opposing ends of said ring are rotated toward the narrowest spacing between the peripheries of said first and second recesses and as said threaded fastener is rotatably advanced on said first spindle end portion.

An expandable fastener assembly for use in conjunction with an internally threaded member comprising:

• an elongated screw body having a longitudinal axis, a first end and a second end and an exteriorally threaded end portion, said screw body defining an elongated cavity extending therethrough which is co-axial with said longitudinal axis and a series of circumferentially spaced apart expansion slots opening onto said threaded end portion and extending radially into said body to communicate with said cavity, said cavity having a cylindrically shaped segment extending from an interior end in said threaded end portion of said body to an opening on said first end, and a frusto-conically shaped segment joining the interior end of said cylindrically shaped segment and extending to an opening on said second end, the diameter of said frusto-conically shaped segment increasing at a first, predetermined constant rate moving from it's joinder with said cylindrically shaped segment to it's opening on said second, end;
• an elongated spindle having a cylindrically shaped end portion adapted for close conforming, slidable disposition within said cylindrically shaped segment of said cavity and a frusto-conically shaped boss attached to one end of said cylindrically shaped end portion, the diameter of said boss increasing at a second predetermined constant rate moving from it's joinder with said one end portion to an end thereof, said second predetermined rate being greater than said first predetermined rate the axial lengths of said frusto-conically shaped segment of said cavity and of said boss being essentially equal;
• means for releasably securing said spindle at a desired position in said cavity such that said screw body assembly can be locked at a desired position within an internally threaded member, and
• means for gripping said screw body for threadably advancing and retracting said screw body into and from an internally threaded member.

An expandable fastener for use in locking relationship with an interiorly threaded member comprising

• an expandable bolt having an elongated, exteriorly threaded body and a bolthead attached to one end of said body, said bolt defining a cavity extending therethrough which is co-axial with a longitudinal axis thereof, said cavity including a cylindrically shaped first segment extending from a first opening on said bolthead to a position in a central region of said body, and a frusto-conically shaped second segment communicating with said first segment and extending to a second opening on a free end of said body, and
• an elongated spindle having a first cylindrically shaped portion adapted for relatively close fitting slidable engagement with said first segment, and a second portion forming a frusto-conically shaped boss connected to said first portion, said boss being insertable by it's smaller end into said second opening and segment to expand said threaded body to lock said bolt to an interiorly threaded member, said bolthead defining a first circular recess disposed eccentrically within a second circular recess, said first opening being centered on a base of said first recess and being sized to retain a threaded fastener therein while being rotatably adjusted on a threaded end portion of said first spindle segment which projects out of said cavity through said first opening, said second recess being sized to retain a circular split locking ring therein when said ring is disposed about said threaded fastener and said threaded fastener is disposed in said first recess such that opposing ends of said ring bind between said threaded fastener and a peripheral wall of said second recess as opposing ends of said ring are rotated toward the narrowest spacing between said first and second recesses as said threaded fastener is rotatably advanced on said first segment.