Fitting for attachment to perforated members

Claim 1

A FITTING FOR ATTACHMENT TO A PERFORATED MEMBER COMPRISING A BUSH OF DEFORMABLE ELECTRICAL INSULATING MATERIAL HAVING STOP MEANS ADJACENT ONE OF ITS ENDS, SAID BUSH BEING DIMENSIONED TO PASS PART AWAY THROUGH A PERFORATION IN SAID MEMBER TO AN EXTENT DETERMINED BY SAID STOP MEANS, SAID STOP MEANS BEING POSITIONED SO THAT THE OTHER END OF SAID BUSH PROJECTS BEYOND SAID PERFORATION, AN ANNULAR GROOVE FORMED AROUND SAID BUSH BETWEEN SAID STOP MEANS AND SAID OTHER END OF SAID BUSH, SAID GROOVE BEING POSITIONED ALONG THE LENGTH OF THE BUSH SO AS TO REGISTER AT LEAST IN PART WITH THE THICKNESS OF SAID PERFORATED MEMBER WHEN SAID BUSH IS FITTED THEREIN, AN ANNULAR SEAL ARRANGED IN SAID GROOVE, A SPIGOT OF ELECTRICAL CONDUCTING MATERIAL FOR INTRODUCTION INTO THE BORE OF THE BUSH, THE SPIGOT INCLUDING A FRUSTO-CONICAL SHAPED ENLARGEMENT OF THE SPIGOT CROSS-SECTION SO POSITIONED ALONG THE LENGTH OF THE SPIGOT THAT WHEN THE SPIGOT IS LOCATED WITHIN THE BORE, THE FRUSTO-CONICAL ENLARGEMENT LIES AXIALLY BEYOND THE EDGE OF THE MEMBER DEFINING THE PERFORATION, TO EXPAND THE PROJECTING END OF THE BUSH RADIALLY OUT JUST BEYOND SAID EDGE DEFINING SAID PERFORATION, A PROJECTION ON SAID SPIGOT INTERMEDIATE SAID FRUSTO-CONICAL SHAPED ENLARGEMENT AND THE END OF THE SPIGOT REMOTE FROM THAT WHICH IS INTRODUCED INTO SAID BORE, THE EXTENT TO WHICH THE SPIGOT MAY BE INTRODUCED THEREIN BEING DETERMINED BY SAID PROJECTION AND A SUBSTANTIALLY CYLINDRICAL ENLARGEMENT OF THE SPIGOT CROSS-SECTION INTERMEDIATE SAID FRUSTOCONICAL SHAPED ENLARGEMENT AND SAID PROJECTION ALONG SPIGOT, SAID CYLINDRICAL ENLARGEMENT BEING POSITIONED ALONG THE LENGTH OF THE SPIGOT SO THAT WHEN THE SPIGOT IS LOCATED WITHIN THE BORE, SAID CYLINDRICAL ENLARGEMENT REGISTERS AT LEAST IN PART WITH SAID GROOVE TO EXPAND THE PORTION OF THE BUSH CONTAINING THE GROOVE AND THEREBY URGE THE SEAL INTO SEALING ENGAGEMENT WITH SAID PERFORATED MEMBER.