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To all whom it may concern: Be
it known that I, S. F. VAN CHOATE,
of the city and State of New York, have invented an Insulator for
Telegraphic Purposes; and I do hereby declare that the following, taken
in connection with the drawings which accompany and form part of this
specification is a description of my invention sufficient to enable
those skilled in the art to practice it. The
great difficulty experienced in transmitting and receiving telegraphic
signals through or by means of long stretches of wire or other
conductors in rainy weather or in humid atmospheres arises, not from the
fact that the electric fluid passes from the wire-conductor through the
substance of the insulator glass or bone rubber, but it is the fact that
the electric current or fluid finds a path to the ground along the
surface moisture or film of vapor or other conducting-matter which has
condensed or settled upon the outer surfaces of the wire, glass, or bone
rubber and the surfaces of the post or other suspending apparatus. This
film may not be perceptible to the eye or to the touch, yet it may be
sufficient to carry off a portion of the current.
These escapes, as in the case of posts, form so many leaks of the
current to the ground, and consequently returns of the same to the
opposite pole of the battery, (this being the normal tendency of the
electric fluid,) so that the supplying battery-force fails to reach the
distant instrument with full vigor, or, in other words, fails to
complete its circuit through the distant instrument, but turns back at
these various escaping-points, forming the difficulty which telegraphers
call a “ground” or “return” where by the distant effect desired
to be produced upon the receiving apparatus does not take place.
Many devices have been presented with a view to obviate this
serious difficulty, and which heretofore has rendered telegraphing so
uncertain during rainy or foggy weather.
The following is my plan for obviating this difficulty, which is
called "Van Choate's Insulator."
In the accompanying drawings, Figure 1 is In Fig. 2, B represents a longitudinal section of the bracket, C being a common iron pin-hook incased in bone-rubber, as at a a, which is firmly screwed into the wooden pin B, while D represents a sectional view of the part called the "cavity-plate," which is made of cast-iron or other suitable material. A vertical view of the same cavity-plate is shown at Fig. 3, and an end upright view at Fig. 4. The peculiar-shaped cavity, with its angles or grooves, as shown at b b in Figs. 1 and 2, forms the principal feature of this invention. |
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The
hub-shaped barrel or cylinder c c, Fig. 2, of the cavity-plate is
very important. It serves for two purposes. It closes up the large
cavity A, so as to prevent the moisture from settling or condensing in
the chamber, while the lower projection or lip, d d, forms a drip
to prevent the rain from running into the cavity-space. The drawing is
made upside down. When the
insulator is secured to the post or other support the hook hangs
underneath, so as to hold the wire. The cavity-plate is beveled on its
outer under edge, and fits tightly in the groove cut into the wood, and
is secured in its place by menus of two small brads or nails, as at c
c. The
object of the peculiar-shaped cavity A and the plate D is that when the
whole are combined a dry space is secured between the hook and the outer
surfaces of the wooden pin. This
dry space prevents the electric current from escaping from the wire to
the ground by means of any dampness which might be settled or formed
upon the outer surfaces of the wire, hook, bracket, or post. The open
space around the stem or neck of the hook at f f; Fig. 2, is so
small, and by means of the cylinder shape of the hub of the plate D the
moisture would have to follow up this small space a considerable
distance before it could spread on the roof of the cavity around the
base of the hook. The
object of the second groove, b b, or indentation at the angle of
the cavity is to give corners and jambs at various angles to prevent the
dampness or moisture from spreading should it get inside of the cavity,
while the lower projection of the cylinder of the plate forms a drip to
prevent the rain or other water from running into or closing up the
opening around the neck of the suspending-hook. Fig.
5 shows a plate with an outer rim or drip,
as at g g, which is a double protection against the rain running
into the hollow around the hook. In
order to protect the surfaces of the wooden bracket, as well as the
plate and hook, and to prevent the surfaces of the metal from oxidating
or absorbing moisture, and also in order to keep insects out of the
cavity, particularly to prevent spiders from building their webs inside
the cavity or on the bracket or hook, I coat them over, inside and out,
with a composition whose principal base is asphaltum, and whose
principal solvent is naphtha. This composition forms a black varnish or
paint, which makes the surfaces of the wood and iron impervious to
moisture and protects the former from oxidation, while it renders the
latter imperishable in the air. What
I claim is-- 1.
The combination of the cavity A, face plate D, and pin4iook C, for the
purposes set forth. 2.
The wooden bracket B, plate D, and hook C, as above combined, when
coated with the composition as above, and for the purposes set forth. S.
F. VAN CHOATE. Witnesses:
GEO. T. ANGELL
GEO. A. DARY.
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