US 2004/0167525 A1 · Anti-splay medical implant closure with multi-stepped removal counterbore

Abstract

An anti-splay closure with a multi-stepped counterbore includes a cylindrical body with an external, helically extending anti-splay guide and advancement flange and a breakaway installation head. The body includes a central bore formed by a plurality of component bores diminishing in diameter in steps toward a forward end of the body to create shoulders which intersect the bores at circular edges. The circular edges form multiple locations for engagement by a reverse threaded, self-tapping fastener removal tool or easy-out. The closure is used with an open headed bone implant screw which is provided with internal, helically extending mating guide and advancement structures complementary to the flange of the body so that said body is rotatably receivable in said bone screw.

Claims21

Dependent claims

A closure for setting engagement with a structural member and comprising:

(a) a substantially cylindrical body having an outer cylindrical surface relative to a central axis;
(b) a guide and advancement flange extending helically about said outer cylindrical surface, said flange having a leading surface and a trailing surface relative to a direction of forward advancement along said axis;
(c) at least one of said leading surface and said trailing surface being compound in contour spaced from said body cylindrical surface and including an inward facing anti-splay surface component facing generally toward said body axis;
and
(d) said body having a multi-stepped bore formed therein, said multi-stepped bore including a plurality of substantially cylindrical component bores sequentially diminishing in diameter in steps toward said direction of forward advancement thereby forming a plurality of cylindrical surfaces that intersect shoulders at respective circular edges sized and shaped so as to be adapted to provide a grip to an easy out tool.

2 more elements

A closure for setting engagement with a structural member and comprising:

(a) a substantially cylindrical body having an outer cylindrical surface relative to a central body axis of rotation;
(b) an external guide and advancement flange extending helically about said outer cylindrical surface, said flange having a trailing surface relative to said forward advancement direction;
(c) said trailing surface being compound in contour and including an inward anti-splay surface component facing generally toward said body;
(d) said body having a multi-stepped bore formed therein, said multi-stepped bore including a plurality of substantially cylindrical component bores diminishing in diameter in steps from a rear surface of said body toward a forward direction thereof along said axis thereby forming a plurality of cylindrical surfaces that intersect shoulders at respective circular edges;
and
(e) said cylindrical component bores diminishing in such steps and having such cylindrical lengths as to form said respective circular edges having locations and diameters sized and shaped so as to enhance engagement of said body by a reverse threaded, self-tapping removal tool.

3 more elements

A closure for setting engagement with a structural member and including a substantially cylindrical body having an outer cylindrical surface relative to a central axis and a guide and advancement flange extending helically about said outer cylindrical surface relative to said axis, said flange having a leading surface and a trailing surface relative to said forward advancement direction, and wherein:

(a) at least one of said leading surface and said trailing surface being compound in contour and including an inward anti-splay surface component facing generally toward said fastener axis;
and
(b) said body having a multi-stepped bore formed therein, said multi-stepped bore including a plurality of substantially cylindrical component bores diminishing in diameter in steps toward said forward advancement direction thereby forming a plurality of cylindrical surfaces that intersect shoulders at respective circular edges.

Dependencies are inferred from the claim text.

Anti-splay medical implant closure with multi-stepped removal counterbore

Life of this patent

Anti-splay medical implant closure with multi-stepped removal counterbore

Life of this patent

Abstract

Claims21