Publication: Electrical World
New York, NY, United States
A Novel Tree Insulator.
It is safe to say that a large proportion of the troubles on overhead electric circuits is due to grounds, leaks and broken wires caused by imperfect insulation and support of the conductors where they pass among trees. In order to provide more effective means for the insulation and support of wires under these and other unfavorable conditions, the Brodie Electric Company, of Manchester, N. H., has brought out a line of special insulators, one form of which is shown in the accompanying illustration.
It will be noticed that insulation is secured by the use of a petticoat glass insulator supported by a malleable iron collar which is attached to the lag screw in such a way that the collar and the screw are adjustable with respect to each other, so that no matter what the inclination of the tree limb to which it is attached the insulator may always remain in a vertical position and its insulating surfaces dry. The wire is carried on a porcelain pulley held by a bifurcated metallic "pin which screws into the thread in the glass and is cemented in place. The pulley not only furnishes additional insulation to the wire but allows it to move freely so that the strain on the conductor is equalized and the liability to trouble from broken wires minimized.
"Another form of the device is provided with a cleat with two screw boles instead of the lag screw, and adjustable like it. This form is especially designed for use upon smaller tree branches and on buildings and cross arms.
If a third form is adapted to replace the rubber hook, the use of which is discouraged by the underwriters, attachment to the building or cross arm being made by a single screw. All three forms are made with a malleable iron hook of the usual form in place of the pin and porcelain pulley if so desired.
There is nothing combustible about these insulators and nothing likely to deteriorate by action of the weather; they are strong and durable and easily put in place, and it is claimed that they are capable of furnishing insulation to wires among trees equal to that of the other portions of the line, a result unattainable by the use of devices the insulating surfaces of which are unprotected from the rain.