Underwriters Laboratories, Inc.

Jeffrey B Hall

William D Parker

A sharpener apparatus includes a base, a linear bearing assembly mounted on the base, and a support block carried by the bearing assembly for reciprocating movement along a rectilinear path relative to the base. A planar abrasive surface underlies the support block which has one or more open channels for receiving workpieces in sliding relation with the longitudinal axes of the workpiece preferably inclined to the abrasive surface. A pusher member is supported by the support block adjacent each channel for applying a constant force longitudinally of the corresponding workpiece to urge its tip against the abrasive surface. Manual or powered reciprocating movement of the support block effects an abrasive action of the workpiece tips against the abrasive surface to form a highly accurate and repeatable tip geometry, such as a chisel point, on each workpiece.

Sharpener apparatus

An apparatus for testing a dielectric sample for susceptibility to surface electrical failure due to tracking. The apparatus includes an enclosure continuously purged of air-borne contaminants, which eliminates external drafts, and a base disposed within the enclosure for supporting the dielectric sample. A pair of electrodes are operably interconnected with a variable voltage power supply and adapted to engage the dielectric sample on a first side with a mutual separation. A source of water and water borne contaminants intermittently discharges the water and water-borne contaminants in droplet form onto the dielectric test sample between the electrodes.

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Clayton, NC, United States of America

Jeffrey B Hall