PNEUMATISCHE BOHREINRICHTUNG

摘要

An automated and adjustable control system for conducting peck drilling operations wherein a drill bit is advanced stepwise in successively increasing penetrations, rapidly retracted after each penetration to remove cuttings, thereafter rapidly advanced toward a work face and then slowed to a drilling advanced rate beginning with the bit a predetermined distance from the work face. Preferably, a pneumatic means rapidly retracts the drill upon completion of each penetration step. A feed rate control unit is partially retracted but limited to a distance less than retraction of the drill. When the drill is rapidly advanced by pneumatic means during each penetration step, the feed rate is decreased by the feed rate control unit to a uniform drilling rate prior to engaging the work face in the work piece.