Oil switch having anti-flash device for restricting arc type discharges upon switch openings

Claim 1

AN ELECTRICAL OIL CIRCUIT-BREAKING SWITCH, COMPRISING A GENERALLY TUBULAR ENCLOSURE OF AN ELECTRICALLY INSULATING MATERIAL CONTAINING AN OIL FILLING; A CONDUCTIVE ROD AXIALLY SHIFTABLE WITHIN SAID ENCLOSURE; FIRST CONTACT MEANS SLIDABLY ENGAGING SAID ROD AND SECOND CONTACT MEANS WITHIN SAID ENCLOSURE AXIALLY SPACED FROM SAID FIRST CONTACT MEANS AND ENGAGEABLE BY SAID ROD UPON SHIFTING THEREOF BETWEEN AN OPEN-CIRCUIT POSITION AND A CLOSED-CIRCUIT POSITION; AND AN ANTI-FLASH DEVICE WITHIN SAID ENCLOSURE BETWEEN SAID FIRST AND SECOND CIRCUIT MEANS FOR RESTRICTING THE DEVELOPMENT OF AN ARC DISCHARGE BETWEEN SAID SECOND CONTACT MEANS AND SAID ROD UPON WITHDRAWAL OF SAID ROD FROM SAID SECOND CONTACT MEANS, SAID ANTI-FLASH DEVICE COMPRISING A TUBULAR CAGE GENERALLY COAXIAL WITH SAID ROD, A PLURALITY OF ELECTRICALLY NONCONDUCTIVE SECTORAL ELEMENTS RECEIVED IN SAID CAGE AND RADIALLY SHIFTABLE THEREIN, SAID ELEMENTS DEFINING IN AN INNERMOST POSITION THEREOF A PERIPHERALLY CLOSED TUBE HAVING AN AXIAL APERTURE FOR SAID ROD OF A CROSS-SECTIONAL AREA SMALLER THAN THAT OF SAID ROD TO RESTRICT THE AREA SURROUNDING AN ESTABLISHED ARC UPON WITHDRAWAL OF SAID ROD THROUGH SAID DEVICE, THEREBY THROTTLING THE PATH OF THE ARC AND CREATING TURBULENCE IN SAID OIL FILLING, SPRING MEANS SURROUNDING SAID ELEMENTS FOR URGING SAME INWARDLY BUT ENABLING RESILIENT EXPANSION OF SAID ELEMENTS RADIALLY OUTWARDLY BY SAID ROD UPON INSERTION OF SAID ROD THROUGH SAID CAGE BETWEEN SAID ELEMENTS, AND MEANS ON SAID CAGE SPANNING SUBSTANTIALLY THE ENTIRE CROSSSECTION OF SAID ENCLOSURE SURROUNDING SAID ROD FOR BLOCKING THE PASSAGE OF A DISCHARGE PAST SAID DEVICE OTHER THAN THROUGH SAID AXIAL PASSAGE.