Improvements in the Manufacture of Electrical Cables for Submarine Telegraph purposes.
Year: 1898

page_text: Date of Application, 7th Nov., 1898
Complete Specification Left, 6th Sept., 1899--Accepted, 7th Oct., 1899
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Electrical Cables for Submarine
Telegraph purposes.
I, LUDWIG LEHMANN HARTVIGSON, of 59, Heathland Road, Stoke Newington,
London, N., Engineer, do hereby declare the nature of this invention to be as
follows:-
con-
This invention relates to the manufacture of electric cables for telegraphic
purposes and it has for its object to increase the speed of signalling through such
cables and it consists in such a construction as to increase the weight and reduce
the electrical resistance of the conductor per unit of length whilst retaining the
same diameter of conductor and the same thickness of the dielectric, or
versely, or to decrease the inductive capacity for the same weight of conductor,
the same resistance per unit of length, and the same total diameter of cable, and
conversely to reduce the total diameter and effect a saving in the dielectric with
the same inductive capacity and the same weight of conductor per unit of length
as when a cable of stranded wires is employed.
The invention consists in forming the cable conductor of a central wire sur-
rounded by wires of segmental cross section so as with the central wire to form a
conductor of complete circular cross section so as to comprise within a cross-
sectional area of least possible diameter the greatest possible amount of conductive
metal, the wires of segmental section being wound spirally around the centre
wire and in close juxtaposition thereto and to each other so as to leave no inter-
vening spaces and form a conductor almost equal in weight per unit of length
to a solid rod but possessing nearly all the flexibility of an ordinary stranded
wire cable.
The segmental form may be imparted to the surrounding wires by drawing
the wires of the appropriate form in the first instance or by bringing them to that
form by drawing or rolling them immediately before or after they are wound
upon the central wire.
1
1000
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
Improvements in the Manufacture of Electrical Cables for Submarine
Telegraph purposes.
I, LUDWIG LEHMANN HARTVIGSON, of 59, Heathland Road, Stoke Newington,
London, N., Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
-
My invention relates to the manufacture of electric cables for telegraphic pur-

page_text: poses and it has for its object to increase the speed of signalling through such
cables, more especially in the case of submarine cables of great length, and also
to effect a saving in the amount of di-electric ordinarily required.
The invention consists of such a construction of the core of such telegraph-
cables as to increase the weight and reduce the electrical resistance of the con-
ductor per unit of length whilst retaining the same diameter of conductor and
the same thickness of di-electric, or conversely; or to decrease the inductive
capacity for the same weight of conductor, the same resistance per unit of length,
and the same total diameter of core; and conversely to reduce the total diameter
of core and effect a saving in the di-electric, still retaining the same inductive
capacity and the same weight of conductor per unit of length as when a core con-
taining a conductor of stranded wires is employed.
Reference is to be had to the accompanying drawings forming part of this
specification wherein Figure 1 is a cross section of a core constructed according
to my invention, Figure 2 being a side elevation of a portion of the core with the
insulating covering partly removed so as to shew the conductor.
According to my invention the conductor is formed of a central wire a sur-
rounded by wires 6 of segmental cross-section such as together with the central
wire a to form a conductor of complete circular cross-section (as shewn in
Figure 1) comprising within a cross-sectional area of least possible diameter
the greatest possible amount of conductive metal the wires b of segmental section
being wound helically around the central wire a in close juxtaposition thereto
and to each other so as to leave no intervening spaces and thus to form a con-
ductor almost equal in weight per unit of length to a solid wire of the same
diameter but possessing nearly all the flexibility of an ordinary stranded wire
conductor. eee forms the non-conducting or di-electric covering for the con-
ductor as a whole.
I have found that it is necessary to use an uneven number of segmental wires b
for the reason that such an arrangement gives much greater flexibility to the
conductor than can be obtained with an even number of segmental wires, and
that a core so constructed may be subjected to severe bending tests without dis-
turbance of the relative positions of the various wires composing the conductor.
The segmental form may be imparted to the surrounding wires by drawing
those wires of the appropriate form in the first instance, in which case (as in the
usual practice of forming wire-stranded conductors) these segmental wires might
be led through dies or guides of the proper form to ensure their accurate dis-
position relatively to the central wire and to one another when being laid up
to form a conductor. Or the surrounding wires may be brought to the segmental
form by drawing or rolling them immediately before or after they are wound
upon the central wire.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The manufacture of electric telegraph submarine cables containing cores
with a conductor consisting of a central wire with an uneven number of closely-
juxtaposed wires of segmental cross-section wound helically upon such central
wire and thereafter covered by a di-electric substantially as and for the purposes
specified.
2. Electric cores for submarine telegraphic purposes constructed substantially
as specified.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.