Safety pressure vessel for carbonated beverages and the like

Claim 1

A SAFETY CAP STRUCTURE FOR A PRESSURE VESSEL HAVING A WIDE-MOUTHED OPENING DEFINED BY AN ANNULAR PROJECTION OF ITS WALL AND IN WHICH THE FREE END PORTION OF SAID PROJECTION IS FLARED OUTWARDLY TO PROVIDE AN INTERNAL CONICAL SEALING SURFACE COMPRISING A FLANGED DISC-LIKE CAP ADAPTED TO BE RECEIVED OVER SAID OUTWARDLY FLARED END OF SAID ANNULAR PROJECTION WITH THE FLANGE THEREOF CONCENTRIC WITH AND RADIALLY OUTWARD OF SAID ANNULAR PROJECTION, SAID CAP HAVING AN INNER ANNULAR SEALING SURFACE CONCENTRIC WITH BUT RADIALLY INWARD OF SAID CONICAL SEALING SURFACE, A PLURALITY OF CIRCUMFERENTIALLY EXTENDING AND CIRCUMFERENTIALLY SPACED LUGS CARRIED BY SAID ANNULAR PROJECTION AND POSITIONED ON THE OUTSIDE THEREOF BETWEEN THE OUTER END OF THE FLARED PORTION THEREOF AND THE BODY OF SAID CONTAINER; EACH OF SAID LUGS HAVING A FLAT PORTION EXTENDING GENERALLY PARALLEL WITH THE SAID END OF SAID FLARED PORTION OF SAID PROJECTION, AN INTERMEDIATE PORTION INCLINED STEEPLY TOWARD THE BODY PORTION OF SAID CONTAINER, AND AN END PORTION SLIGHTLY INCLINED TOWARD SAID BODY PORTION OF THE CONTAINER, A SEALING RING WHICH IS OF INVERTED U-SHAPE IN RADIAL CROSSSECTION HAVING SIDE WALL PORTIONS LYING AGAINST SAID CONICAL AND ANNULAR SEALING SURFACES, THE FLANGE ON SAID CAP HAVING RADIALLY INWARD DIRECTED DETENTS TO ENGAGE UNDERNEATH SAID LUGS AND TO COMPRESS SAID SEALING RING UPON ROTATION OF SAID CAP ON SAID ANNULAR PROJECTION IN ONE DIRECTION AND THE CONSEQUENT MOVEMENT OF THE CAP TOWARD THE BODY PORTION OF SAID CONTAINER, THE ARRANGEMENT BEING SUCH THAT SAID SEALING RING IS INEFFECTUAL WHEN SAID DETENTS ARE UNDER THE FLAT PORTIONS OF SAID LUGS BUT IS OPERATIVE TO EFFECT A SELF-SEALING ACTION WHEN SAID DETENTS ARE UNDER THE SLIGHTLY INCLINED END PORTIONS OF SAID LUGS WHEN SAID SLIGHTLY INCLINED PORTIONS ARE IN THEIR NORMAL POSITIONS WITH RESPECT TO SAID CONICAL SEALING SURFACE, AND SAID SLIGHTLY INCLINED PORTIONS OF SAID LUGS BEING YIELDABLE IN AN OUTWARD DIRECTION PARALLEL WITH THE AXIS OF SAID ANNULAR PROJECTION WHEREBY UPON THE APPEARANCE OF EXCESSIVE PRESSURE WITHIN THE CONTAINER SAID CAP CAN LIFT OFF SLIGHTLY TO RENDER SAID SEALING RING INEFFECTUAL AND THUS PERMIT THE RELEASE OF EXCESS PRESSURE IN SAID CONTAINER.