UNITED STATES PATENT OFFICE
DAVID BROOKS, OF PHILADELPHIA, PENNSYLVANIA.
Letters Patent No. 69,622, dated October 8, 1867.
IMPROVEMENT IN INSULATORS FOR TELEGRAPHS.
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 certain Improvements in
Insulators for Telegraph Wires; and I do hereby declare the following to
be a full, clear, and exact description of the same. My
invention relates to the construction of insulators for telegraph wires,
the main feature of my invention consisting of the combination
substantially as described hereafter, of a vessel or tube of blown glass
with a telegraphic-wire insulator, so that a more perfect insulation may
be attained. In
order to enable others skilled in the art to make and use my invention,
I will now proceed to describe its construction and operation, reference
being had to the accompanying drawing, which forms a part of this
specification, and in which-- Figures
1 and 2 are sectional elevations of my improved insulator us it appears
when partly completed. Figure
3, an inverted sectional view of the insulator complete; and Figures
4 and 5 modifications of my invention. In
figs. 1, 2, and 3, A is a cast-iron wire-holder, which consists of a
stem, a, having at one end the usual curved arms b b.
B is a metal case, open at one end, and C is a vessel of blown
glass, the opposite sides of which are flattened, as shown in fig. 3.
D is a hollow cylinder or band of glass, porcelain, or
earthenware, and is of such a size as to surround the neck of the vessel
C without being in contact therewith at any point.
A band, x, pf paper or other fabric is cemented to the
inside of the case B, a short distance from the open end of the same.
Melted sulphur is poured into the case, and the vessel C is
inserted in the position shown in figs. 1 and 2, the upper surface of
the sulphur being above the lower edge of the paper band x. Melted paraffine is new poured on to the sulphur in the case,
and the cylinder D is so adjusted that it will be secured in the
position shown in fig. 2 by the hardened paraffine.
The remaining annular space between the cylinder B and the case B
is then filled with melted sulphur.
The stem a of the holder A is now introduced into the vessel C,
and is secured by melted sulphur, with which the said vessel is partly
filled, melted paraffine being poured onto the top of the sulphnr after
the latter has become hard. The
case is now heated and then inverted, so that all the paraffine except
that absorbed by the sulphur, and that which remains in the annular
portion of fig. 3, between the cylinder B and the paper band y,
will escape. The case and
its contents are then allowed to cool, after which paraffine is again
poured into the vessel C, so as to cover the surface of the sulphur in
the same, and form a ring or belt, around the stem. I
have found, after lengthened and repeated experiments, that blown glass
is a much more perfect insulating medium than glass pressed in a mould,
for the reason that the surface of pressed glass contains minute
fissures, in which moisture or dust collects, and permits the escape of
electric currents. I have also found that the inner surface of a
blown-glass vessel is much less liable to collect and retain moisture
than the outer surfaces of the same.
By the substitution, therefore, of a blown-glass vessel for the
pressed or moulded cup or cylinder of glass heretofore employed, the
wire-holder is much more perfectly insulated, while the amount of glass,
and consequently the weight of the insulator, is reduced.
A tube, c, of blown glass, as shown in fig. 4, may be
substituted for the glass vessel illustrated in figs: 1, 2, and 3.
A vessel of blown glass may be used in the manner illustrated in
fig. 5, when it is desired to dispense with the case B and wire-holder,
the wire in this case being wrapped round the vessel, which is adjusted
to the pin n in a manner clearly shown in the drawing.
The body m of paraffine contained within the annular
recess y perfectly insulates the holder from the case, and the
recess thus situated serves to retain the paraffine in its place, even
if it should he melted by the heat to which insulators are sometimes
exposed. By the use of a detachable cylinder, B, the recess for the
reception of the paraffine may be formed after the vessel C has been
introduced into the casing, the expense of so constructing the case as
to form a recess or receptacle for the paraffine being thus avoided. I claim as my invention, and desire to secure by Letters
Patent-- 1. The combination, substantially as described, of a
vessel or tube of blown glass with a telegraphic wire insulator, for the
purpose described. 2. A wire-holder, A, and case B, in combination with a
tube or vessel, C, of blown glass, arranged between the holder and case,
and insulated from both, substantially as and for the purpose specified. 3. A recess, y, arranged between the case B and
holder A, and containing paraffine for the purpose set forth, 4:
A detachable cylinder, D, arranged in respect to the holder, case B, and
vessel C, and insulated from the same, substantially as and for the
purpose set forth. In testimony whereof I have signed my name to this
specification in the presence of two subscribing witnesses.
DAVID BROOKS. Witnesses:
JOHN WHITE,
C. B. PRICE.
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