Improvements in Electric Cables.
Year: 1891

page_text: Date of Application, 12th Nov., 1891
Complete Specification Left, 12th Aug., 1892-Accepted, 1st Oct., 1892
PROVISIONAL SPECIFICATION.
Improvements in Electric Cables.
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 Messrs. Felten &
Guilleaume, of Mülheim on the Rhine, in the German Empire, Cable Manu-
facturers,) to be as follows:-
This invention relates to electric cables, particularly such as are intended for
use for telephonic transmission and where complete metallic circuits are employed.
A telephone cable constructed according to this invention comprises several strands
twisted together and sheathed with lead or other suitable protecting material.
Each strand consists by preference of four flat wires or metallic ribbons, each
insulated from the other by means of a wrapping of paper or other suitable
material. The four, or other number of flat wires are arranged flatwise one upon
the other, so as to form a bar or bundle approximately square in cross section, and
the bundle is then twisted. This latter treatment has the effect of fixing and per-
manently retaining the several conductors in position in relation to one another.
The strand is in addition served, either before or after the twisting operation, with
a coating of paper or other insulating material.
When four of the flat wires or metallic ribbons are grouped together in a strand,
the alternate or the extreme and mean conductors are connected together to form
two closed circuits; this arrangement destroying induction and securing improved
efficiency, particularly in long distance telephony.
A cable instead of being composed of several strands each constructed in the
manner described, may consist of a single bundle of flat wires or ribbons each
insulated from the other but laid flatwise together so as to present an approximately
square cross section, the group or bundle being then twisted, served with a further
coating of paper or other insulating material and finally sheathed with lead or other
protective covering. Or several such twisted bundles, each enclosed in a lead
covering, may be twisted together to form a cable, the whole being ultimately
furnished with an additional lead or other protective sheathing. Such envelope
may, if necessary, be lined internally and protected externally by means of the
usual kind.
1
1001
COMPLETE SPECIFICATION.
Improvements in Electric Cables.
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 Messrs. 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, particularly such as are intended for
use for telephonic transmission, and where complete metallic circuits are employed.
A telephone cable made according to this invention is illustrated in the accom-
panying drawings; Fig. 1 being a side elevation (having parts cut away to shew
the construction), and Fig. 2 a transverse section.

page_text: The improved cable A comprises several strands B twisted together and sheated
with lead C or other suitable protective material. In the present design, the
cable is composed of seven strands, each consisting by preference of four flat wires
or metallic ribbons b, b1, b2 and 3, and each insulated from the others by means of
a wrapping e, e¹, c² or c³ of paper or other suitable material. The four or other
even number of flat wires are arranged flatwise one upon the other, so as to form a
bar or bundle approximately square in cross section, and the strand or bundle is
then twisted. This latter treatment has the effect of fixing and permanently
retaining the several conductors b, b¹, ³ and b³ in position in relation to one
another; but its primary object is to neutralise, and thus to prevent the effect of,
induction as between one conductor and another. The conductors 6 and 63, in con-
junction with the transmitting and receiving instruments, form a closed circuit; the
conductors 6 and 2 being similarly comprised in another close dcircuit. Or, the
conductor may be in communication with the conductor 62, and the conductor 61
in communication with the conductor 68. In either of these cases, two closed
circuits are formed. Each strand or bundle in addition to being twisted is served,
either before or after the twisting operation, with a coating Cx of paper or other
insulating material. Instead of each strand being composed of four conductors, as
in the present illustration, any other even number of conductors may be employed.
A cable, instead of being composed of several strands B each constructed in the
manner described, may consist of a single bundle of flat wires or ribbons b, bª, 6ª and 6ª,
each insulated from the others, but laid flatwise together so as to present an
approximately square cross section; the group or bundle being then twisted, served
with a further coating of paper or other insulating material C*, and finally sheathed
with lead or other protective covering. Or, several such twisted bundles, each
enclosed in a lead covering, instead of or in addition to the paper coating C*, may
be twisted together to form a cable; the whole being ultimately furnished with an
additional lead or other protective sheathing. The sheathing C may, if necessary,
have an internal lining C³, and be protected externally by means of the usual kind.
A telephone cable constructed in the manner above described possesses the
following advantages:-When, for instance, four of the flat wires or metallic
ribbons are grouped together in a strand, the alternate or the extreme and mean
conductors can be connected together to form two closed circuits; this arrangement
destroying induction and securing improved efficiency, particularly in long distance
telephony. The flat shape of the conductor is also advantageous for the utilization of
capacity for the purpose of facilitating telephonic communication. The flat shape
of the conductor does not, however, interfere with the employment of insulating
material containing air-spaces when it is desired to reduce the capacity.
Having now particularly described and ascertained the nature of this invention
tion, and in what manner the same is to be performed, I claim :-
MIN
1. The herein-described improved electric cable consisting of one or more pairs
of flat conducting wires or ribbons, the several conductors being laid flatwise upon
but insulated from one another, the pair or each pair of conductors serving to
convey flow and return currents in a closed circuit and the bundle being ultimately
twisted.
.H
2. The herein-described improved electric cable comprising several strands or
bundles, each strand consisting of one or more pairs of flat wires or ribbons, laid
flatwise upon but insulated from one another, each pair of conductors serving to
convey flow and return currents in a closed circuit, and the whole group composing
the strand being ultimately twisted.
3. The improved electric cable constructed substantially as herein described and
comprising several strands or bundles, each consisting of one or more pairs of flat
wires or ribbons, such as b, served with insulating material, such as c, and laid
together flatwise, the whole strand or bundle being subsequently twisted, and,
either before or after the twisting operation, provided with an insulating covering C*,
substantially as herein described.

page_text: 4. The improved electric cable constructed substantially as herein described
and comprising several strands or bundles, each consisting of insulated ribbons,
such as b, twisted together to form a strand or strands, such as B, the strand or
strands being then insulated and laid up into a cable and enclosed in a sheathing,
5 such as C, substantially as herein described.
The 10th T1 1000