Apparatus for vacuum gassing sand forms

Claim 1

IN A CHECK VENT FOR A CORE BOX ADAPTED FOR USE IN CURING A SAND FORM THE COMBINATION WHICH COMPRISES A RIGID METAL CYLINDER DISPOSED IN AN APERTURE IN A WALL OF SAID CORE BOX AND ARRANGED IN SEALING CONTACT THEREWITH, SAID CYLINDER HAVING A TRANSVERSE BARRIER PROVIDED WITH A PLURALITY OF SUBSTANTIALLY PARALLEL SLOTTED OPENINGS WHICH EXTEND THERETHROUGH, SAID OPENINGS BEING SIZED TO OBSTRUCT THE PASSAGE OF SAND WHILE PERMITTING THE PASSAGE OF GAS THERETHROUGH AND A FLEXIBLE DISK SEATED IN SAID APERTURE ADJACENT SAID CYLINDER AND EXTENDING ACROSS THE BORE THEREOF, SAID DISK HAVING A SURFACE ARRANGED FOR SEALING CONTACT AT THE PERIPHERY OF SAID APERTURE TO SEAL SAID APERTURE AGAINST THE ENTRY OF GAS INTO SAID CORE BOX WHENEVER THE PRESSURE OF GAS THEREWITHIN IS LESS THAN ATMOSPHERIC PRESSURE AND TO OPEN SAID APERTURE TO ALLOW THE PASSAGE OF GAS OUT OF SAID CORE BOX WHENEVER THE PRESSURE OF GAS THEREWITHIN IS GREATER THAN ATMOSPHERIC PRESSURE, SAID DISK HAVING A RIDGE MOLDED UPON A SURFACE THEREOF, A FASTENER RECEPTACLE DISPOSED ADJACENT SAID DISK AND AN ELONGATED METAL FASTENER LODGED IN SAID RIDGE OF SAID DISK, SAID FASTENER EXTENDING THROUGH AT LEAST A PART OF SAID DISK INTO SAID FASTENER RECEPTACLE AND RETENTIVELY ENGAGED THEREIN.