Battery casing with improved seal and vent

Claim 1

IN A BATTERY INCLUDING A FIRST CASING PART HAVING SIDE WALLS AND AN END WALL, BATTERY PLATES AND AN ELECTROLYTE FOR PROVIDING A D.C. VOLTAGE ACROSS THE PLATES, THE IMPROVEMENT COMPRISING: A SECOND CASING PART IN CONFRONTING RELATION TO SAID FIRST CASING PART AND FORMING THEREWITH AN ENCLOSURE FOR SAID BATTERY PLATES AND ELECTROLYTE, AND RESILIENT SEALING MEANS POSITIONED AROUND THE PERIPHERAL PORTION OF SAID SECOND CASING PART, SAID SEALING MEANS HAVING A PORTION EXTENDING TO THE OUTER AXIALLY FACING SIDE OF SAID SECOND CASING PART WHREIN OUTWARD MOVEMENT OF THE SECOND CASING PART WILL MOVE THE SEALING RING OUTWARD WITH IT, SAID FIRST CASING PART HAVING AN INWARDLY EXTENDING PORTION FORMING AN OUTWARDLY AXIALLY FACING SEAT FOR THE INNER AXIALLY FACING SIDE OF SAID SEALING MEANS, SAID SECOND CASING PART HAVING A PROTION EXTENDING TO AN OUTER AXIALLY FACING PORTIN OF SAID SELAING MEANS WHERE IT BEARS AGAISNT THE SEALING MEANS TO PRESS THE SAME AGAINST SAID SEAT TO FORM A GAS TIGHT SEAL FOR THE BATTERY, AND SAID FIRST CASING PART HAVING A VENT PASSAGE COMMUNICATING BETWEEN THE OUTWARDLY AXIALLY FACING SURFACE OF SAID SEALING MEANS SEAT AND THE EXTERIOR OF THE BATTERY AND WHICH, UNDER NORMAL INTERIOR PRESSURES OF THE BATTERY, IS SEALED BY THE SEALING MEANS AND, UNDER ABNORMALLY HIGH INTERIOR GAS PRESSURES WHICH MOVES SAID SECOND CASING PART AND THE SEALING MEANS OUTWARDLY, IS UNSEALED TO PERMIT ESCAPE OF GAS THROUGH THE RESULTING CLEARANCE BETWEEN THE SEALING MEANS AND THE SEAT THEREFOR.