Improvements in Electric Cables.
Year: 1895

page_text: Date of Application, 20th Aug., 1895
Complete Specification Left, 21st May, 1896-Accepted, 27th June, 1896
PROVISIONAL SPECIFICATION.
Improvements in Electric Cables.
1, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the
City of London, Civil Engineer and Chartered Patent Agent, do hereby declare
the nature of this invention (a communication to me from the Firm of Felten &
Guilleaume, of Mülheim-on-the-Rhine, in the German Empire, Cable Manu-
facturers,) to be as follows:-
This invention relates to electric cables principally intended for aërial use; same
comprising an insulated conductor, or insulated conductors twisted together, and an
outer protective covering of india-rubber, india-rubber compound, gutta percha or
the like.
In constructing, according to this invention, a cable for telephonic or telegraphic
purposes, a number of insulated electric conductors are twisted together, india-
rubber or the like being then pressed about the group. A braiding, weaving or
other protective covering of hemp, jute, thin wire or the like, may then be added.
In constructing cables for conveying high tension currents, the conductor may
consist of a single wire, or of two or more wires, or of a wire and a surrounding
tube arranged concentrically and insulated from one another, surrounded with a
pressing of india-rubber or the like, and enclosed within a protective covering as
before described.
Dated this 20th dor of Awe 1805
I, GEORGE GATTON MELHUISH HARDINGHAM, of 191, Fleet Street, in the
City of London, Civil Engineer and Chartered Patent Agent, do hereby declare
the nature of this invention (a communication to me from the Firm of Felten &
Guilleaume, of Mülheim-on-the-Rhine, in the German Empire, Cable Manu-
facturers,) 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 electric cables, principally intended for aërial use; same
comprising one or more conductors, each surrounded by air confined within a tube
or envelope of non-conducting material, embedded in a mass or enclosed within a
covering of india-rubber, india-rubber compound, gutta-percha or the like; such
covering serving to protect the insulated conductor or conductors from the effects
of moisture and to take the place of the heavy lead sheathing which is usually
employed for this purpose.
In the accompanying drawings, which illustrate in transverse section several
examples of electric cables constructed in accordance with this invention,
Fig. 1 represents an "air-space" cable, for use in telephonic and telegraphic
transmission, in which the conductors are disposed in pairs, each pair being enclosed
within but, so far as possible, out of contact with, and unsupported by, a bi-part
tube of non-conducting material, such, for instance, as paper.

page_text: The cable represented in Fig. 2 is of a similar kind except that the several
conductors are separately enclosed within tubular coverings which also serve to
confine air.
Figs. 3, 4 and 5 represent cables adapted for conveying heavy currents; Fig. 3
showing a cable with a single insulated conductor, Fig. 4 a cable with two insulated
conductors arranged side by side, and Fig. 5 a cable with two insulated conductors
arranged concentrically.
Referring to Figs. I and 2, in constructing, according to this invention, a cable
for telephonic or telegraphic purposes, a number of electric conductors a a, enclosed
within bi-part or other tubes of insulating material bare served with a pressing c
of india-rubber or the like; which, owing to its soft state, is capable of being
applied to insulated conductors of the kiud referred to without crushing the
air-spaces. A braiding, weaving or other protective outer covering d of hemp,
jute, thin wire or the like, may, when necessary, be added. In Fig. 1, each bi-part
tube enclosing a pair of conductors a a is twisted; whilst in Fig. 2, two or more
of the conductors a, with their tubular envelopes 6 of insulating material, are
twisted together; or the whole group may be twisted before being served with
the pressing of india-rubber or the like.
In constructing cables for conveying heavy currents, the conductor may consist
of a single wire a (Fig. 3), or there may be two or more conducting wires a a
(Fig. 4), or two conductors a and a¹ may be arranged concentrically and insulated
the one from the other by non-conducting material (Fig. 5); the insulated
conductor or conductors being, in each instance, surrounded by a pressing c of
india-rubber or like material capable of being applied in a plastic or soft state
about a delicate body, such as a paper tube forming the boundary to an air-space
around an electric conductor or conductors. A protective outer covering or
braiding d may be added.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
1. An electric cable comprising conductors each enclosed within an insulating
envelope, the material of which is, so far as possible, out of contact with, and
unsupported by, the conductor, the said envelopes being enclosed within a soft
pressing" of rubber or similar protective material, applied in a plastic state and
without crushing the envelopes upon the conductors, substantially as set forth.
46
2. In an electric cable, the combination with conductors, each enclosed within an
insulating envelope which, so far as possible, is free from contact with, and is
unsupported by, the conductor, an air-space being thus maintained about the
latter, of a soft "pressing" of india-rubber or similar protective material, applied
in a plastic state without crushing the envelopes upon the conductors, and an
outer protective covering of hemp, jute, thin wire or the like, substantially as
specified.
Dated this 30th day of April 1896.
G. G. M. HARDINGHAM.