US 5,122,134 AGranted

Surgical reamer

AssigneePfizer Hospital Products Group, Inc.

InventorsRocco R. Borzone, Frank B. Gray

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Abstract

The cutting head for a surgical reamer has a leading end for insertion into a bone canal and a trailing end for attachment to a drive shaft. The cutting head has a cutting surface formed about an axis of rotation of the cutting head. The cutting surface is formed by the rotation of the cutting edges on a plurality of flutes spaced around the axis of rotation. Each cutting edge has a first portion spaced a predetermined radial distance from the axis of rotation at the tip portion and terminates at a terminating point which is at a greater radial distance from the axis of rotation than the starting point. The cutting edge on each flute has a second portion having a starting point at the trailing end of the cutting head which is at a second predetermined radial distance from the axis of rotation. The second portion extends axially towards the tip portion and terminates at a point at a greater radial distance from the axis of rotation than the starting point thereof. A third curved portion starts at the terminating point of the first portion and terminates at the terminating point of the second portion and intersects the first and second portions tangentially.

Claims16

Dependent claims

A cutting head for a surgical reamer of the type having a series of circumferentially spaced flutes extending from a leading end of the cutting head, said leading end for insertion into a bone, to a trailing end of the cutting head, each flute having a cutting edge thereon generating upon rotation a surface of revolution formed about an axis of rotation of the cutting head, said cutting edge of each flute comprising:

a curved central portion intermediate the leading and trailing ends of said cutting head formed as a sector of a torus;
a first section extending in a straight line from a point at a first radial distance from said axis of rotation adjacent the leading end of the cutting head to a point of intersection on said central portion at a second radial distance from said axis of rotation, said second radial distance being larger than said first radial distance, said straight line of said first section forming a tangent with said sector of a torus at said first point of intersection;
and
a second section extending in a straight line from a point at a third radial distance from said axis of rotation adjacent the trailing end of the cutting head to a first point of intersection on said central portion at a fourth radial distance from the axis of rotation, said fourth radial distance being greater than said third radial distance, said curved central portion being disposed at a greater radial distance from said axis of rotation than said second and fourth distances, said straight line of said second section forming a tangent with said sector of a torus at said second point of intersection.

1 more element

Dependencies are inferred from the claim text.