Drive system for prosthetic fasteners

A threaded fastener with tool engaging means on a threaded shank adapted for use with a drive tool, said tool engaging means comprising:

• an end surface formed on an end of said fastener;
• a recessed socket formed in said end surface for receiving a drive tool, said recessed socket having a top edge and a bottom edge;
• a central axis extending through said fastener;
• alternating merging concave and convex curved partially-cylindrical surfaces formed inside said recessed socket, the axes of curvature of said partially-cylindrical surfaces being generally parallel to each other and to said central axis, said recessed socket formed with six concave partially-cylindrical surfaces;
• beveled surface portions formed on said concave partially-cylindrical surfaces sloping towards the central axis from the tope edge of the recess to the bottom edge thereof for releasably engaging complementarily beveled surface portions formed on said drive tool, said beveled surface portions formed on at least three alternately spaced concave partially-cylindrical surfaces such that each beveled surface portion neighbors at least one non-beveled concave partially-cylindrical surface.

A threaded fastener with tool engaging means on a threaded shank adapted for use with a drive tool, said tool engaging means comprising:

• an end surface formed on an end of said fastener;
• a recessed socket formed in said end surface for receiving a drive tool, said recessed socket having a top edge and a bottom edge;
• a central axis extending longitudinally through the fastener;
• alternating merging concave and convex partially-cylindrical surfaces formed inside said recessed socket, the axes of curvature of said partially-cylindrical surfaces being generally parallel to each other and to said central axis, said recessed socket formed with at least five concave partially-cylindrical surfaces;
• beveled surface portions formed on at least three concave partially-cylindrical surfaces in said recessed socket of which at most two of said beveled surfaces are formed on neighboring concave partially-cylindrical surfaces, said beveled surface portions slope towards the central axis from the top edge of the recess to the bottom edge thereof for releasably engaging complementarily beveled surface portions formed on mating convex partially-cylindrical surfaces formed on said drive tool;
• said complementarily beveled surface portions being sloped inwardly towards said central axis.

A fastener and driver combination comprising:

• a threaded fastener with an end surface formed on an end of said fastener, engagement means formed on said end surface for receiving said driver, said recessed socket having a top edge and a bottom edge, a central axis extending longitudinally through said fastener;
• a driver for imparting rotational torque to said fastener and including a drive bit portion engagable with said engagement means, a bit axis extending longitudinally through said bit;
• alternating merging concave and convex partially-cylindrical surfaces formed on an outside surface of one of said engagement means and said bit, mating partially-cylindrical surfaces formed on an inside surface on the other of said engagement means and said bit, the axes of curvature of said partially-cylindrical surfaces being generally parallel to each other and to said central axis and said bit axis for releasably retaining said fastener on said driver, at least five convex partially-cylindrical surfaces formed on said outside surface and matingly engagable concave partially-cylindrical surfaces formed on said inside surface;
• beveled surface portions being formed on said concave partially-cylindrical surfaces of said inside surface, said beveled surface portions sloping inwardly towards said central axis at an angle from the top edge of the recess to the bottom edge thereof, said beveled surface portions being formed on at least three concave partially-cylindrical surfaces of which at most two of said beveled surface portions are formed on neighboring concave partially-cylindrical surfaces, correspondingly beveled surface portions formed on said outside surface on each convex partially-cylindrical surface.

A threaded fastener and driver combination, said fastener being formed with tool engaging means on a threaded shank for engagement with said driver, said tool engaging means comprising a recessed socket formed in an end of said shank for receiving a cooperatively formed portion of said driver, said recessed socket having a top edge and a bottom edge;

• a central axis extending longitudinally through the fastener;
• alternating concave and convex partially-cylindrical surfaces formed inside said recessed socket, the axes of curvature of said partially-cylindrical surfaces being generally parallel to each other and to said central axis, said recessed socket formed with at least three concave partially-cylindrical surfaces;
• beveled surface portions sloping towards the central axis from the top edge of the recess towards the bottom edge thereof and are formed on three of said concave surfaces being disposed generally at the apices of an equilateral triangle;
• said driver being formed for imparting a rotational torque to said fastener when engaged therewith and including a bit portion formed with alternating concave and convex partially-cylindrical surfaces for complementary engagement with said alternating concave and convex partially-cylindrical surfaces formed inside said recessed socket, complementary beveled surface portions formed on each of said convex surfaces of said bit portion for complementary engagement with said beveled surface portions formed on three of said concave surfaces formed in said recessed socket, when said driver is engaged with said fastener, said beveled surfaces formed on said convex partially-cylindrical surfaces releasably engaging said beveled surface portions formed on three of said concave surfaces formed inside said recessed socket.

A fastener and driver combination comprising:

• a threaded fastener with engagement means formed on said end surface for receiving said driver, a central axis extending longitudinally through said fastener;
• a driver for imparting rotational torque to said fastener and including a drive bit engagable with said engagement means, a bit axis extending longitudinally through said bit and being coaxial with said central axis when said bit is engaged with said engagement means;
• alternating merging concave and convex partially-cylindrical surfaces formed on an outside surface of one of said engagement means and said bit, corresponding partially-cylindrical surfaces formed on an inside surface on the other of said engagement means and bit, said inside surface being defined by a top edge and a bottom edge thereof, axes of curvature of said partially-cylindrical surfaces being generally parallel each other and with said central axis and said bit axis for releasably retaining said fastener on said driver, at least six convex partially-cylindrical surfaces formed on said outside surface and matably formed concave partially-cylindrical surfaces formed on said inside surface;
• first beveled surface portions formed at the apices of a triangle formed between three of said partially-cylindrical surfaces formed on said inside surface, said first beveled surface portions being sloped inwardly towards said central axis from said top edge towards said bottom edge, second beveled surface portions cooperatively formed on each of said convex surfaces formed on said outside surface for engagement with said first beveled surface, when said bit is releasably inserted into said engagement means said bit is triangularly releasably engaged in said engagement means to prevent said fastener from wobbling when driven by said driver.