To all whom it may concern:

I, SAMUEL OAKMAN, of Boston, in the county of Suffolk and State of Massachusetts, have invented a certain new and useful Te1egraphic Insulator, of which the following is a specification.

The Nature of the Invention.

The nature of my invention consists in constructing, as an article of manufacture, an insulator of glass, so formed interiorly that it may be easily and securely attached to its support, and exteriorly that it protects the wire surrounding it and its supporting-plug.

Description of the Accompanying Drawing.

Figure 1 is a perspective view of my insulator.

Figure 2 is a vertical section, showing the insulator and supporting plug.

Figure 3 is a horizontal section made on the line x y, fig. 2.

General Description.

The outside of my insulator is made of the general shape represented in fig. 1, A being the upper, B C being a projecting flange to extend over the neck or contracted part, D D, around which the wire passes. 

The object of the projecting flange is to protect the wire from rain; in other words, to shed the water and to prevent the drip from accumulating on the wire.

The lower part E E, of the insulator, is made as shown, in the usual manner.

The interior of my insulator is

formed, as shown, in section, figs. 2  and 3, the upper end being of the form shown in fig. 3, while the lower end, c d, is circular in form.

The long diameter, a' b', of the upper part of the interior is longer than the diameter c d, fig. 2, of the lower part, so that if the stock H, fig. 2, is driven in, with the wedge K inserted as shown, the wood will fill the incline recesses a c a' and b d b', and thus hold the insulator firmly in place.

By this arrangement it will he seen that when the insulator is once fastened to the stock H, it will not work off, as the wood is forced into the recesses a' b', figs. 2 and 3, so that the insulator can not be revolved and work itself loose, as is common to the insulator now used.

The shape and dimension of the recesses a' b' may be varied, if thought desirable, the idea being to have the upper part, a' b’, of the recess larger in some of its dimensions than the lower part, c d, also, to have it somewhat irregular in shape; so that, when the stock is once adjusted into it, the insulator will not be likely to turn around and thus work itself loose, or be pulled off even in case it should become loose.

I claim as my invention--

A glass insulator, as a new article of manufacture, when the same is formed with the projecting flange B C, the neck D D, and the dovetailed recesses a' c d b’, substantially as described, and for the purpose set forth.

       SAMUEL OAKMAN.

Witnesses:

FRANK G. PARKER,

E. A. NICKERSON.