US 5,735,732 AGranted

Precision drill sharpener and grinding wheel assembly therefor

OwnerDavid A. Bernardinventor

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Abstract

A precision drill sharpener and grinding wheel assembly is provided, as is a corresponding drill chuck for use with the drill sharpener, in which the drill sharpener includes a lever and spring clip alignment subassembly for properly positioning a drill in the drill chuck, and sharpening ports for sharpening the drill and splitting the drill tip, the sharpening ports being positioned such that a single grinding wheel assembly is used to both sharpen the drill and split the tip. The drill sharpener uses a small diameter grinding wheel operated at high speed to provide cutting rates comparable to large industrial sharpeners. The drill chuck is of short length, relative to most of the drills to be sharpened, and is open at a back end, enabling the manipulation of the drill by its shank relative to the drill chuck when disposed in the alignment subassembly.

Claims23

Dependent claims

A drill sharpener comprising:

a housing;
a grinding wheel assembly comprising a grinding wheel disposed within said housing;
a drill mounting chuck having a barrel portion;
a pair of peripheral cams carried by the barrel portion of the chuck;
said housing contains at least two chuck receiving ports, said at least two chuck receiving ports including an alignment port having an opening therein for receiving and positioning a drill relative to the chuck and the cams carried by the chuck;
a second port having a chuck receiving opening therein to position the chuck and the drill in operative relation to a grinding surface of the grinding wheel for sharpening said drill;
wherein the alignment port houses a pair of spring clips for engaging a drill to be aligned and subsequently sharpened, said spring clips being mounted such that leading edges of the spring clips are substantially parallel to each other, said spring clips further being biased toward a first closed position at which said leading edges are closely spaced, and means for moving said spring clips to an open position wherein said leading edges are spread apart such that a drill can be inserted past said leading edges in said alignment port, said spring clip moving means further permitting said spring clips to return toward said first position, wherein said leading edges can engage the drill for alignment purposes.

4 more elements

A drill sharpener comprising:

a housing;
a grinding wheel assembly comprising a grinding wheel operatively coupled to said motor shaft;
a drill mounting chuck;
a pair of peripheral cams carried by the barrel portion of the chuck;
said housing defining at least one chuck receiving ports having a chuck receiving sleeve therein to position the chuck and a drill in operative relation to a grinding surface of the grinding wheel;
wherein said grinding wheel is made of steel and is of a small diameter, and said grinding surface comprises diamond plated to said grinding wheel;
wherein said motor operates at speeds on the order of 15,000 revolutions per minute,
and wherein said grinding wheel assembly is coupled to said motor shaft in a direct drive arrangement;
and wherein said grinding wheel assembly comprises:
an electrically non-conductive hub having a central bore extending through at least a lower portion thereof, said bore being sized to be press fit onto said motor shaft, said non-conductive hub having a cylindrical peripheral surface extending along at least a portion of the longitudinal extent of said hub;
and wherein said grinding wheel comprises a hollow steel cylinder having said diamond plating bonded to an exterior peripheral surface thereof, said steel cylinder being secured to said non-conductive hub, wherein an interior surface of said wheel is mated with said cylindrical peripheral surface of said non-conductive hub;
and wherein said grinding wheel assembly further comprises a heat sink disk made of a material having high thermal conductivity secured to an upper extent of said non-conductive hub to secure said grinding wheel in its proper longitudinal position on said hub, and being in intimate contact with said hub to draw heat away from said hub for dissipation into an environment.

9 more elements

Dependencies are inferred from the claim text.