Improvements in Insulating Electrical Conductors.
Year: 1891

page_text: Date of Application, 2nd Apr., 1891
Complete Specification Left, 1st Jan., 1892-Accepted, 6th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in Insulating Electrical Conductors.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, (a communi-
cation to me from abroad by Edward Crawford Davidson, of 109 West 12th
Street, in the City of New York, State of New York, United States of America,
Solicitor,) do hereby declare the nature of this invention to be as follows: ---
This invention relates to insulated conductors in which paper is employed as the
insulating medium. The object of the invention is to increase the tensile strength
of the paper tape or ribbon applied to the conductor spirally, and at the same time
have the width of the ribbon or tape so narrow that it may be wound spirally
around relatively small conductors either in an open spiral or with the edges of the
spiral abutting or overlapping. In insulating telephone wire it would be desirable
to wind the paper ribbon or tape in open spirals so that air spaces would exist
throughout the insulation, the purpose being to reduce the static capacity of the
conductor to a minimum. To accomplish these ends I take a twisted ribbon of
paper or a paper cord, and having dampened it by steaming or otherwise, pass it
through rolls by which it is pressed into the form of a flat ribbon or tape. This
tape has great tensile strength and may be wound upon small or large conductors
in any manner desired. One or more such windings may be applied around the
wire and over such winding I may wind a smooth flat ribbon as a kind of envelope.
Any suitable insulating compound may be employed. The wires may be
individually encased in a lead sheath or may be made up into a cable which may be
covered with a lead sheath. This insulation may be applied while damp, and if so
when the conductor is dried out the paper in shrinking contracts and firmly grasps
the conductor.
Dated this and dev of Al 1801
CARPMAEL & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Insulating Electrical Conductors.
1, SYDNEY PITT, of Sutton in the County of Surrey, Gentleman (a communi-
cation to me from abroad by Edward Crawford Davidson, of 109 West 12th
Street, in the City of New York, State of New York, United States of America,
Solicitor) do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement :-
This invention relates to that class of insulated conductors in which paper is
employed as the insulating medium.
The object of the invention is to so insulate a conductor that the paper insulation
wound around it may have a high tensile strength and may at the same time be so
narrow that the ribbons, strands, or tapes of paper may be wound spirally around
relatively small conductors, such as are employed for telephonic and other purposes,
either in open spirals-that is, with a spiral space between the edges of the paper
strand or tape or be wound with the edges abutting or overlapping, if desired.
In insulating telephone wires it would be desirable to wind the paper ribbon or tape
in open spirals, so that air spaces may be provided throughout the insulation in
order to reduce the static capacity of the conductor to a minimum. This is,

page_text: however, unnecessary where the conductor is to be used for currents of a different
character. Where it is desired to wind the insulating paper ribbons or tapes in
open spirals it is practically impossible to wind flat ribbons around small conductors
such as are used for telephonic purposes-say, for instance, around a No. 18 wire-
because the relation of bias and diameter are such that a ribbon of paper that could
be wound around such a conductor in an open spiral would have to be so narrow
that its tensile strength would not be sufficient to permit the winding of the ribbon
upon the conductor in any way that would be practicable. To overcome this
difficulty, and also to increase the tensile strength of paper insulation however
wound around electrical conductors, and yet employ a flat strand or tape of paper,
I
proceed as follow:-Paper cord or paper twisted more or less to approximate the
compactness of ordinary paper cord, or indeed paper twisted much more loosely, is
preferably dampened by steaming or otherwise and is then passed through rolls or
otherwise pressed out into the form of a flat ribbon or tape, which will necessarily
be composed of multiple layers of paper. This tape has great tensile strength, and;
as is obvious, may be made relatively narrow, so that it may be wound upon small
or large conductors in any manner desired.
In the accompanying drawings,
Figure 1, shows a paper cord or a ribbon of paper twisted more or less tightly
and the same cord rolled into a flat tape.
Figure 2 illustrates the application of such a tape to an electric conductor, the
tape being wound in an open spiral.
Figure 3 is a similar view showing the tape wound upon a conductor with its
edges abutting.
Figure 4 shows the application of a number of paper tapes or ribbons to an
electrical conductor.
Figure 5 is a cross-section of a cable of conductors insulated according to the
invention, and
Figure 6 is a perspective view of the end of an electric light or power conductor
similarly insulated.
A indicates a section of twisted paper or paper cord. A' shows the same cord
after being rolled into the form of a tape.
B indicates the electrical conductor.
In Figure 2 the tape is wound upon the conductor so as to leave an open spiral
space c between its edges. In Figure 3 the tape is wound upon the conductor with
its edges abutting, as indicated by c. In Figure 4 are shown three tapes A'
wound one upon the other, the successive tapes being of increasing width and
wound so as to break joints. If desired and as shown in this figure a flat paper
ribbon D may be wound around the insulation A and this ribbon may be coated
with an insulating, waterproofing and sealing compound E. Conductors insulated
in this manner may be laid up into cables, as indicated in Figure 5, and protected
by an exterior lead sheath F.
As shown in Figure 6, each conductor may be enveloped in a lead or other
suitable sheath F, where the size of the conductor and the purpose for which it is
intended render it desirable.
If the paper insulation herein described is applied while in a damp condition, in
drying it will contract and firmly embrace the conductor.
As is ordinarily practiced in applying insulation of this general character, the
insulated conductor may be passed through a die or series of dies to compact the
insulation thereon and reduce the insulation to an uniform cross-section.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. An electrical conductor having wound thereon a paper tape composed of
twisted paper or paper cord flattened as described.

page_text: 2. An electrical conductor having an insulating tape wound thercon in an open
spiral, said tape being formed of twisted paper or paper cord flattened, as
described.
T
1001
CARPMAEL & Co.,
Agents for the Applicant.