UNITED STATES PATENT OFFICE
JOHN GARITY, OF EAST BIRMINGHAM, PENNSYLVANIA.
Letters Patent No. 110,645, dated January 3, 1871.
IMPROVEMENT IN GLASS TELEGRAPH-INSULATORS.
The Schedule referred to in these Letters Patent and making part of the same.
To all whom it may concern: Be
it known that I, JOHN GARITY,
of East Birmingham, in the county of Alleghany and State of
Pennsylvania, have invented a new and useful Improvement in Glass
Telegraph-Insulator; and I do hereby declare the following to be a full,
clear, and exact description thereof, reference being had to the
accompanying drawing making a part of this specification, in which-- Figures
1 and 2 are side views of my improved telegraph insulator, differing
from each other only in the form of the head. To
enable others skilled in the art to make and use my invention, I will
proceed to describe the same. The
insulator is made of solid glass by being pressed in a mold having
suitable cavities, in any of the ways known to the art. The
part which is to be inserted into the telegraph pole, cross-bar, or
other support for the wires, is of a tapering cylindrical form, as shown
at a. On
this I form, at the same time and in the same way the rest is formed, a
screw-thread, a', of any desired slope or angle of thread. The
bead b is grooved, as at b’, for convenience in attaching the
telegraph wire, and is made with faces of other than circular form, as
shown in fig. 1, for ease in screwing the pin a into the telegraph-pole
or other support. With this form of insulator-head an ordinary wrench, of form to correspond, is used. Instead of a head of polygonal form, as in fig. 1, with which a wrench is used, a head of circular form may be used, as shown in fig. 2, but in the latter case a pin or lug, c, should be made on the circular head a, so as to admit of the screwing in of the pin a
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by the use of an ordinary spanner of suitable form. To
secure the necessary strength at the base of the head, which commonly is
the weakest point, I make the pin a with a gradual taper from the base
of the head to or toward the point, any desired distance, the object
being to get a larger body of glass in the head end of the pin. A
solid glass insulator of the form described I have found to possess
sufficient strength it all points for practical use, while it is simple
in its construction, is made at small cost, and is easily applied. I
am aware that it is not new in the manufacture of telegraph insulators
to thread a pin or shank which has a uniform diameter from the point to
the base of the head. Insulators so made are exceedingly liable to break where the
pin or shank joins the head, and hence I have devised the form or
construction of insulator shown and described as an improvement thereon. What
I claim as my invention, and desire to secure by Letters Patent, is-- A
solid glass telegraph insulator, having a head, b grooved, and of form
suitable for use with either a wrench or spanner, and having also a
threaded pin, a, the face of which tapers from the base of the head to
or toward the point, substantially as and for the purposes set forth. In
testimony whereof I, the said JOHN GARITY, have hereunto set my hand.
JOHN GARITY; Witnesses: JOHN
GLENN, G.
H. CHRISTY.
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