To all whom it may concern:

Be it known that I, CHARLES C. HINSDALE, of Cleveland, in the county of Cuyahoga and State of Ohio, have invented new and useful Improvements in Telegraph Insulators; and I do hereby declare that the following is a full and complete description thereof.

The nature of this invention relates to that class of telegraph insulators, usually made of glass, &c., for supporting lines ordinarily above ground, and connected with poles and buildings, as is generally done.  The said insulator for this purpose is made of paper-pulp, or pulp composed of vegetable fiber, and formed into the desired shape by molding and compressing the said pulp by mechanical means or otherwise, whereby the said article is shaped for use, and may be employed in place of and in the same relation with telegraph-lines as are the ordinary insulators for that purpose.  In order to give solidity, strength, and density to the paper insulator, and to render the same impervious to the dissolvent action of moisture and the disintegrating influence of the weather, I combine with the pulp of which to make the insulator liquid silica or silicon, and with or without mineral cement.  These ingredients, however, are secondary agents and do not constitute the essential feature of my invention, which consists in making the insulator of pulp composed of any suitable material, and combining therewith the above specified ingredients, or their equivalents, making a new article of manufacture.

I do not confine myself to any one particular shape of the insulator; but such as is shown in the drawings is of the most approved shape.

Figure 1 represents an external side view of a telegraph insulator composed of paper-pulp, as above specified, and shown as attached to a stem or holder for fixing the insulator in place. Fig. 2 is a transverse vertical section of the insulator having attached thereto the stem or holder alluded to.  Fig. 3 is an end view of the insulator.  Fig. 4 is a modification of Fig. 1.

Like letters of reference refer to like parts in the several views.

The preparation of the pulp of which to make the insulator and casting or melding it into shape are us follows: The pulp material is reduced to about the consistency of ordinary flour paste, having mixed therewith the ingredients above specified.  Into a foraminous mold, of the proper shape for an insulator, the prepared pulp is forced by hydrostatic pressure.  For that purpose is employed a hydrostatic force-pump, by which the pulp is pumped into the mold, and by the power of the pump the water is forced out of the pulp and passes off through the perforations in the mold, leaving the pulp therein in a firmly compact or solid condition, and comparatively a dry paper insulator of the shape of the mold.

It will be observed in Fig. 2 that the insulator is provided with a female screw, A. Said screw is formed by means of a mandrel having thereon a thread.  Thus the mold is filled with pulp and compressed therein to a solid condition, as above described, the mandrel is then screwed into the mold and into the paper insulator therein, thereby forming the screw-thread A in the insulator.  The operation of screwing the

mandrel into the insulator in the mold causes an increment of pressure, producing a farther condensation of the pulp on the screw part of the insulator equal to the diameter of the mandrel, thereby rendering the said screw part of the insulator all the more firm and durable for holding the supporting stem or holder B when inserted therein.

A modification of the above-described method of molding the insulator consists in first manipulating the paper-pulp into a crude shape of an insulator and then placing the same in a mold.  The screw-mandrel is then screwed into the mold and into the plastic pulp, which is now subjected to a high pressure by any suitable means for expelling the water therefrom, which passes off through the foraminous mold, while the pulp is firmly compressed therein and around the screw of the mandrel in nearly a dry condition.  The mandrel is then screwed out, leaving a female thread in the insulator, which is then taken from the mold.

In the drawings is represented a stem, B, screwed into the insulator C, whereby it is Secured in its respective place when in practical use.  The insulator, however, may be connected to the stems or holders in ordinary use.

The said stem or holder B is shown and described as being a separate and distinct thing, to which the insulator is attached.  The stem and insulator, however, may be of one piece, as shown in Fig. 4, in which C' represents the insulator, and B' the stem, the two being formed together in a mold, and both of the same material-- viz., paper-pulp. It is preferred to have the two parts separate, and then unite them, as herein described, and shown in the drawings.

As hereinbefore remarked, the essential feature of my invention is a telegraph-insulator, C, separate and distinct from the stem or holder B, and composed of paper-pulp, which may have combined therewith liquid silica or silicon, to indurate and strengthen the same, and to render it a better non-conductor, irrespective of the means that may be employed for its manufacture.

What I claim as my invention, and desire to secure by Letters Patent, is--

1. As a new article of manufacture, a telegraph-insulator constructed of paper-pulp, or a pulp of other fibrous material, substantially as herein set forth, and for the purpose specified.

2. A telegraph-insulator constructed of a composition of paper-pulp, or a pulp of other suitable maternal and liquid silica or silicon or other equivalent cementing agent, substantially as herein set forth, and for the purpose specified.

3. A telegraph-insulator consisting of an insulating-head, C, and supporting stem or holder B, formed in one piece and constructed of the same material-- viz., paper pulp substantially as herein set forth.

In testimony whereof I affix my signature in presence of two witnesses.

CHARLES C. HINSDALE.

Witnesses:

W. H. BURRIDGE,

J. H. BURRIDGE.