Publication: Electrical World
New York, NY, United States
A New Insulator
We illustrate herewith a new form of insulator for which a patent has been granted to Albert Vickers and Wm. Dibb, of Syracuse, N. Y., and which is manufactured by the Noti Insulator Company, of the same place. The insulator is designed to do away with tie-wires, and is very simple and cheap. The trouble with the present form of insulator, necessitating the use of a tie-wire, is appreciated by all telephone and telegraph construction men. The theoretically perfect way of suspending a wire is to rest it in a perfectly smooth saddle of glass or porcelain not in contact with any other wire or metal liable to cause corrosion and mechanical injury to the wire. The only difficulty in carrying out this idea seemed to be the provision of a practical method of anchoring the wires to each insulator. It was with this end in view that the insulator here described was devised. The wire rests easily in a cavity in the top of the insulator and is held firmly, but not jammed, against one wall of the cavity. It is in contact with nothing but smooth, rounding surfaces of glass or porcelain; there is no chance for abrasion or mechanical injury, and the wire is securely anchored.
The lower part of the insulator is of the ordinary pattern, screwing to the pin, except that a less number of threads may be employed, as the insulator cannot unscrew. The top of the insulator is provided with a cavity shaped as shown in Figs. 1 and 2, and two opposite recessed slots. A cylindrical plug slightly tapered, as shown in Fig. 3, is provided of same material as the insulator, and of a diameter less by the thickness of the wire used than the greatest width of cavity.
The wire is laid in the slots and plug pushed home until the groove in plug comes opposite the wire, thus crowding the wire slightly against the wall of the cavity. It will be seen that with plug in position, the wire cannot be withdrawn in any direction, cannot fly up, and the resistance to lateral pull is enormous. In experiments made by cutting the line wire close to the insulator it is stated that the wire beyond did not slip a particle, and during a six months' test, leaving one inch of wire beyond the insulator, the wire has not moved. The principle of the insulator can be better seen in Fig. 4, and depends on the roller action of the plug against the narrowing sides of the cavity, binding the wire tighter as the endwise pull increases. It is almost impossible for the plug to come out unless intentionally removed, as the bearing of the wire against the groove in the plug serves to keep it in place.