Expansion plug

Claim 1

A RESILIENT EXPANSION PLUG COMPRISING A HEAD; A PAIR OF ELONGATED DEFORMABLE TONGUES DEFINING BETWEEN THEMSELVES AN ELONGATED SLOT, SAID TONGUES HAVING FIRST END PORTIONS INTEGRAL WITH SAID HEAD, SECOND END PORTIONS DISTANT FROM SAID HEAD, AND SAID TONGUES BEING OPPOSITELY BOWED TO DEFINE OUTWARDLY BULGING MEDIAN PORTIONS LOCATED INTERMEDIATE SAID FIRST AND SECOND END PORTIONS, AT LEAST SAID MEDIAN PORTIONS BEING PROVIDED WITH EXTERNAL PROTRUBERANCES; AN INTEGRAL CONNECTING WEB OF LESS WIDTH THAN SAID TONGUES EXTENDING ACROSS SAID SLOT BETWEEN THE SECOND END PORTIONS OF SAID TONGUES; AND A PAIR OF ARCUATE ELONGATED LEAF SPRINGS OF A WIDTH NO GREATER THAN THAT OF SAID TONGUES RECEIVED IN SAID SLOT AND CONFORMING TO THE BOWED CONFIGURATION OF SAID TONGUES FOR BIASING THE MEDIAN PORTIONS OF SAID TONGUES AWAY FROM EACH OTHER, SAID SPRINGS HAVING END PORTIONS PROVIDED WITH RECESSES BEING OPENAT THEIR LOWER ENDS FOR ACCOMMODATING SAID WEB.