Closure having pressure-activated release mechanism

Claim 1

APPARATUS FOR RELEASING AN OBJECT FROM THE INTERIOR OF AN AIR-DROPPED CONTAINER UPON CONTACT OF SAID CONTAINER WITH A BODY OF WATER COMPRISING: A TUBULAR CASING HAVING A PERIPHERAL GROOVE FORMED IN THE INNER SURFACE ADJACENT ONE END THEREOF, SAID CASING FORMING PART OF SAID CONTAINER AND HOUSING SAID OBJECT; AND A RESILIENT, DISC-SHAPED CLOSURE MEMBER HAVING A PERIPHERAL PORTION EXTENDING INTO AND RESTRAINED AGAINST MOVEMENT BY SAID GROOVE WHEN SAID CLOSURE MEMBER IS IN A FIRST CONFIGURATION AND BEING WITHDRAWN FROM SAID GROOVE WHEN SAID CLOSURE MEMBER IS FLEXED TO A SECOND CONFIGURATION; A BACK-UP PLATE INTERPOSED BETWEEN SAID OBJECT AND SAID CLOSURE MEMBER, SAID BACK-UP PLATE HAVING AN ANNULAR PORTION BEARING AGAINS THE PORTION OF SAID CLOSURE MEMBER ADJACENT SAID PERIPHERAL PORTION TO PROVIDE A FREE SPACE FOR SAID CLOSURE MEMBER TO ASSUME ITS SECOND CONFIGURATION; THE WEIGHT OF SAID OBJECT BEARING CONTINUOUSLY AGAINST SAID CLOSURE MEMBER AND SAID BACK-UP PLATE WHEREBY CONTACT WITH A BODY OF WATER WILL CAUSE SAID CLOSURE MEMBER TO FLEX FROM SAID FIRST TO SAID SECOND CONFIGURATION TO CAUSE SAID PERIPHERAL PORTION TO BE WITHDRAWN FROM SAID GROOVE AND THE WEIGHT OF SAID OBJECT WILL CAUSE SAID CLOSURE MEMBER AND SAID BACK-UP PLATE TO BE EJECTED FROM SAID CASING.