IMPROVEMENTS IN OR RELATING TO INSULATORS

摘要

1340702 Insulators PILKINGTON BROS Ltd 19 April 1971 [20 April 1970] 18804/70 Heading H2C An electrical insulator comprises insulating bodies 1, e.g. of toughened glass or ceramic material, each having a central recessed head 4 and a shed 2, with a diameter in the range 10 to 24 inches and provided with annular ridge 3. The bodies are connected by metal intercaps 5, e.g. of malleable cast iron 5/ 16 inch thick (or within the range “ to ¥ inch) each having an upper portion 6, receivable in the recess of a head 4, and a lower portion 7, of outer diameter 4 to 14 inches, which surrounds the head of a further body. The bodies and the intercaps are bonded together by cement mortar 8, the inner and outer surfaces of each head 4 and the outer surface of portion 6 of each intercap being formed with dimples or grooves 9 to promote keying with the cement. A top fitting 10, e.g. of malleable cast iron, is bonded round the head 4 of the uppermost body and has lugs 11 or flanges with screw threaded holes 12. A base fitting 13 is bonded to the lowermost body and has holes 17 which coincide with holes 12 of the top fitting so that a number of insulator assemblies can be bolted together to provide a larger insulator (Fig. 2, not shown). Alternatively, a greater number of insulating bodies may be bonded together (Fig. 3, not shown). A further embodiment is described (Figs. 4 to 9, not shown) in which the insulating bodies have annular ridges (3) projecting below the lower limit of shed (2), a flat top wall (25) with recesses (26) formed on its lower surface and vertically extending recesses (28) provided around the outer surface of head (4), the additional recesses improving keying between the bodies and cement. A top fitting (10) (Fig. 5, not shown), having annular ridges (21) on its internal face and a base fitting (13) (Fig. 4, not shown), having external annular ridges (21) and, at its upper end, an inwardly directed annular flange (23) with radial grooves (24) on its upper surface, are employed. Each intercap (5) has annular grooves (27) on its upper, outer surface and part of the lower, inner surface is formed from a plurality of flat regions (29). An inwardly directed flange (30) having radial grooves (31) on its upper surface is also provided at the top of each intercap.