US220729A - Improvement in telephone-cases - Google Patents

Description

G. M. PHELPS. Telephone-Case;

No. 220,729. Patented Oct. 21, I879 UNITED STATES PATENT OEEIoE GEORGE M. PHELPS, OF BROOKLYN, NEW YORK.

IMPROVEMENT lN TELEPHONE-CASES.

Specification forming part of Letters Patent No. 220,729, dated October 21, 1879; application filed August 20, 1879.

To all whom it may concern:

Be it known that I, GEORGE MAY PHELPS,

' of Brooklyn, in the county of Kings and State i usually made of metal, wood, or hard rubber,

all of which substances are objectionable on account of their liability to fracture, or from their expansion and contraction when exposed to moisture or variations in temperature, such expansion and contraction tending to derange the adjustment and working capacity of the apparatus.

The object of my invention is to obviate these objections and to secure a non-expansible, tough, and durable case or holder for telephones.

I have found a useful composition of matter for such purposes toconsist of gum-shellac and some silicate of magnesia, such as asbestus, soap stone, or similar substance. Iprefer to use equal parts of shellac and asbestus, the latter being ground to flour and .mixed with melted shellac, or shellac dissolved in alcohol, and then pressed in suitable molds in a well-known wayand' allowed to cool.

Any desired color may be imparted to the composition by the use of a suitable pigment. I prefer to use lamp-black mixed with the composition before putting it in the mold.

It is obvious that the proportions herein given may be varied within certain limits without departing from the spirit of my invention. I thus secure a tough, hard, and durable telephone-case, resembling hard rubber in appearance, but much cheaper in cost, and not liable, like hard rubber, to expand and contract under varying temperatures.

The accompanyin g drawing represents a sectional view through a well-known form of telephone-casing constructed according to my invention.

I claim as of my own invention- The hereinbefore-described improved telephone ease or holder composed of shellac and asbestus or other suitable silicate.

111 testimony whereof I have hereunto subscribed my name.

G. M. PHELPS.

Witnesses FRANK L. Porn, WM. ARNOUX.

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