Closure for container

Claim 1

A CONTAINER PARTLY DEFINED BY A WALL HAVING AN OPENING THEREIN; A RESILIENT SEALING ELEMENT FOR SAID OPENING HAVING AN ANNULAR OUTER WALL PORTION RECEIVED BY AND ATTACHED TO SAID WALL AT THE OPENING, A RELATIVELY THIN AND FLEXIBLE ANNULAR PORTION JOINING WITH THE ANNULAR WALL PORTION AND INITIALLY INWARDLY THEREOF AND AN INITIALLY UPWARDLY EXTENDING CENTRAL PORTION INCREASING IN RELATIVE THICKNESS INWARDLY FROM THE RELATIVELY THIN AND FLEXIBLE ANNULAR PORTION AND HAVING AN ANNULAR V-SHAPED GROOVE PORTION EXTENDING INWARDLY FROM THE TOP OF THE CENTRAL PORTION AND A PORTION WITHIN THE OUTLINE OF THE ANNULAR V-SHAPED GROOVE PORTION ADAPTED FOR FORMING AN APERTURE THERETHROUGH, SAID ANNULAR WALL PORTION HAVING THREADS THEREON FOR RECEIVING A CLOSING AND OPERATING MEMBER FOR THE SEALING ELEMENT, AND A CLOSING OPERATING MEMBER FOR THE SEALING ELEMENT HAVING A THREADED PORITON FOR RECEPTION BY THE THREADED PORTION OF THE SEALING ELEMENT AND A CENTRAL PORTION FOR ABUTMENT AGAINST THE TOP OF THE UPWARDLY EXTENDING CENTRAL PORTION OF THE SEALING ELEMENT SO AS TO PUSH IT DOWNWARDLY AS THE CLOSING AND OPERATING MEMBER IS THREADED TO THE SEALING ELEMENT WHEREBY THE RELATIVELY THIN AND FLEXIBLE ANNULAR PORTION AND THE CENTRAL PORTION IS FLEXED INTO A GENERALLY HORIZONTAL POSITION WITH THE RELATIVELY THIN AND FLEXIBLE PORTION FLEXED INTO SEALING ENGAGEMNT WITH THE ADJACENT PORTION OF THE UPSTANDING FLANGE AND WHEREUPON THE ANNULAR VSHAPED GROOVE PORTION CLOSES TO FORM A SOLID RIGID PORTION WITH THE CENTRAL PORTION OF THE SEALING ELEMENT AS THAT PORTION FLEXES INTO THE GENERALY HORIZONTAL EXTENDING POSITION.