UNITED STATES PATENT OFFICE
DAVID BROOKS, OF PHILADELPHIA, PENNSYLVANIA.
Letters Patent No. 63,206, dated March 26, 1867.
IMPROVEMENT IN INSULATORS FOR TELEGRAPH WIRES.
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, DAVID BROOKS,
of Philadelphia, Pennsylvania, have invented an Improvement in
Insulating Telegraph Wires; and I do hereby declare the following to be
a full, clear, and exact description of the same; reference being had to
the accompanying drawing, and to the letters of reference marked
thereon. My
invention relates to that class of insulators which are so constructed
that all excessive charge of electricity thrown upon the wire will pass
to an adjacent conductors without rupturing the material which insulates
the wire-holder and my invention consists of an arrangement of the parts
of all insulator constructed in the manner fully described hereafter,
whereby the above result is effected. In
order to enable others skilled in the art to apply my invention, I will
now proceed to describe the manner of carrying it into effect, reference
being had to the accompanying drawing, in which— Figure 1 is a view illustrating one mode of carrying out
my improvement in insulating telegraph wires. Figure 2, a sectional view, showing tail insulated holder
heretofore used, and Figure 3 an inverted plan view of fig. 1. A,
figs. 1 and 3, is a cylindrical metal case, which is secured firmly to
an arm, X, attached to a telegraph pole or other suitable support.
Within the case A is a block B, of dry wood, glass, or other
insulating material, in which is inserted-a wire-holder, C, the latter
being insulated by a coating, a, of hard rubber, gutta percha or other
suitable material. If
desired, a screw may be cut on the outside of the insulating coating a,
so that the holder may be secured in its place or detached with facility
at the lower end of the wire holder are two curved arms or hooks b b,
the ends of which are at such a distance from the lower edge of the case
A that a wire, Y, may be passed between the two.
A holder, consisting of metal hook, C’, (fig. 2,) With an
insulating Coating, a', has heretofore been used, the insulated
end of the holder being screwed directly into the arm X' of the pole or
other support. It has been
found that many of these holders gradually lose their insulating
properties and in a little while become worthless; as, when such holders
are used, and when, by a stroke of lightning or from any other cause,
the wire becomes surcharged with electricity, the latter will escape
from the wire or holder to the nearest conductor by the shortest
passage, which is generally through the insulating coating a' to
the arm X’ which, being wet, is a good conductor, the electricity in
its passage through the coating perforating the latter, and the moisture
passing into the said perforation and forming a conductor along which
the weaker currents, afterwards thrown on to the wire, escape to the
earth. This difficulty has
been heretofore overcome by so arranging the insulated wire-holder in
respect to an exterior conductor that an excessive current thrown on to
the wire will pass from the holder to the conductor without penetrating
the insulating material. My
invention is intended-merely to effect this object in an insulator of
the construction above-described, and illustrated in figs. 1 and. 3 of
the drawing, the difficulty being overcome by so adjusting the case A
and the holder that the distance-from any part of the latter through the
insulating materials a and B to the nearest Conductor is greater
than the distance between the hooks b b and the case A.
When, therefore, the wire is surcharged with electricity, there
will be no inducement for the latter to penetrate the insulating coating
a or wooden block B, as it can much more readily pass from the hooks b
to the casing A. I do not claim broadly the arrangement in an insulator of
any description, of a conductor adjacent to a wire-holder for the
purpose of conducting from the wire excessive charges of electricity,
and thus preventing their passage through the insulating materiel; but I
claim as my invention, and desire to secure by Letters Patent— The
metal casing A., insulating block B, and stem C, arranged and
constructed as described, when the same are combined with arms or
holders b b, so arranged that the distance between the holders
and the case is less than that between the stem and case. In testimony whereof I have signed my name to this
specification in the presence of two subscribing witnesses.
DAVID BROOKS. Witnesses: CHARLES E. FOSTER, W. J. R. DELANY.
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