Publication: Electrical Review
New York, NY, United States
The Dunton Tree Insulator.
The Dunton tree insulator is an ingenious piece of apparatus recently manufactured and placed upon the market by Messrs. Dunton and Field, 117 Main street, Cambridge, Mass. As may be seen from the accompanying illustration this insulator is designed specifically to be used by keeping current-carrying wires from making contact with the swinging limbs of trees. The insulator is so constructed that it can be used with any size of wire, and is made of the highest grade of malleable iron. The arm swings on a sleeve which is lag-screwed to the limb of a tree and turns in a cone-shaped casting pivoted to the lower end of the arm, which allows the glass insulator to be in a vertical position at all times when tied to the wire. A standard locust pin is driven in the cone-shaped casting and can not turn or come out when assembled to the arm. Special lag-screws are furnished with the insulators so that the body of the screw will enter the limb at least three-quarters of an inch, thus giving the full strength of the screw.
This insulator allows the wire to be tied solid to the glass without injury to the wire or to the tree. It allows the limb of the tree to which the insulator is attached to move in any direction. The apparatus is constructed so that any ordinary single, double and triple-petticoated insulator may be used.