Terminal-bushing construction

Claim 1

A TERMINAL BUSHING INCLUDING A FIRST CONICAL SHELL COMPOSED OF INSULATING MATERIAL AND HAVING BOTH THE SMALL AND LARGE ENDS THEREOF OPEN, A GROUND-FLANGE ASSEMBLY ADAPTED TO BE MOUNTED ON ELECTRICAL EQUIPMENT AND INCLUDING A GROUND FLANGE COLLAR HAVING A SUBSTANTIALLY UNIFORM DIAMETER SUBSTANTIALLY EQUAL TO THE DIAMETER OF THE LARGE END OF THE FIRST CONCIAL SHELL, THE LARGE END OF THE FIRST CONICAL SHELL SUBSTANTIALLY ABUTTING AGAINST ONE END OF THE GROUND FLANGE COLLAR, A SECOND CONICAL SHELL COMPOSED OF INSULATING MATERIAL DISPOSED PARTIALLY WITHIN THE FIRST CONCIAL SHELL WITH THE WALL OF THE SECOND CONICAL SHELL TAPERING IN THE SAME DIRECTION AS THE WALL OF THE FIRST CONICAL SHELL, THE WALL OF THE SECOND CONIAL SHELL BEING SPACED FROM THE WALL OF THE FIRST CONICAL SHELL, THE GROUNDFLANGE ASSEMBLY ALSO INCLUDING A RING OF PREDETERMINED THICKNESS SECURED TO THE OTHER END OF THE COLLAR AND FORMING AN ANNULAR SHOULDER, THE SECOND CONICAL SHELL EXTENDING THROUGH SAID RING AND HAVING AN OUTWARDLY EXTENDING ANNULAR FALNGE PORTION AT THE LARG END THEREOF ADJACENT SAID RING AND ABUTTING AGAINST THE ANNULAR SHOULDER FORMED BY SAID RING WHEREBY THE SECOND CONICAL SHELL IS SECURED AGAINST SUBSTANTIAL MOVEMENT FARTHER WITHIN THE FIRST CONICAL SHELL, THE SMALL END OF THE SECOND CONICAL SHELL HAVING AN AXIAL BORE THERETHROUGH OF PREETERMINED DIAMETER, AN AXIALLY-EXTENDING STUD COMPOSED OF CONDUCTIVE MATERIAL EXTENDING THROUGH THE FIRST AND SECOND CONICAL SHELLS AND THROUGH SAID AXIAL BORE, THE STUD HAVING AN ANIN THE SECOND CONICAL SHELL, SAID LAST-NAMED ANNULAR FLANGE ENGAGING THE SMALL END OF THE SECOND CONICAL SHELL ADJACENT THE BORE THERETHROUGH, A SPRING ASSEMBLY MOUNTED ON THE SMALL END OF THE FIRST CONICAL SHELL AND INCLUDING SPRINGS AND A SPRING-SEAT PLATE SECURED TO THE STUD AT A PREDETERMINED POSITION THEREON, AND A CAP ENCLOSING THE SPRING ASSEMBLY, THE SPRINGS OF THE SPRING ASSEMBLY EXERTING FORCE BETWEEN SAID SPRING-SEAT PLATE AND THE SMALL END OF THE FIRST CONICAL SHELL WHEREBY COMPRESSIVE STRESS IS APPLIED TO THE FIRST CONICAL SHELL AND TENSILE STRESS IS APPLIED TO THE SECOND CONICAL SHELL BY WAY OF THE STUD AND THE ANNULAR FLANGE THEREON, THE SECOND CONICAL SHELL BEING INTERPOSED IN THE ELECTRIC FIELD BETWEEN THE STUD AND THE GROUND FLANGE ASSEMBLY AND INCREASING THE BREAKDOWN VOLTAGE OF THE BUSHING.