Importance

Loading Importance Indicators...

Abstract

A hand-held drill is provided that has a pneumatically operated drill motor. A portion of the air that operates the drill motor is directed against the drill motor housing to slidably move the housing within an outer casing to provide a constant feed of the drill bit. The feed rate is controlled by a rate limiter axially aligned with the drill motor and including a piston attached to the drill motor, the piston being mounted within a cylinder filled with hydraulic fluid. The piston has a bore formed through it that permits flow of hydraulic fluid through the bore and a flow control valve is placed within the bore that controls the flow of fluid through the bore to limit the rate of movement of the piston through the hydraulic fluid and thereby control the rate of movement of the drill motor through the casing. Preferably, the drill includes a vacuum collar surrounding the drill bit to remove dust and material particles from the workpiece.

Loading the Abstract Image...

First Claim