Improvements in Electric Cables.
Year: 1893

page_text: Date of Application, 28th June, 1893
Complete Specification Left, 28th Mar., 1894-Accepted, 5th May, 1894
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 abroad from the Firm
of Felten and Guilleaume, of Mülheim-on-the-Rhine, in the German Empire,
Cable Manufacturers,) to be as follows:-
This invention relates to electric cables (and especially subterranean cables) for
use with alternating currents of low tension.
A cable constructed according to this invention has a tubular conductor
composed of a series of wires of special section arranged in a circle about a central
air-space and twisted together so as to retain one another in position. Each wire
is wedge-, hook- or V-shaped in transverse section, or is otherwise formed to
interlock with its neighbours, as is well understood in connection with the
manufacture of armoured cables. Instead of a single tubular conductor, two or
more concentric tubes of similar sectional structure may be employed.
As compared with a tubular conductor in which the metal is continuous in a
circumferential direction, the improved method of construction hereinbefore
described affords greatly increased flexibility.
The tubular conductor of sectional structure is or may be enclosed in a sheathing
of paper or other insulating material; and, with a view to protecting the latter
from moisture, a coating of gutta-percha is next applied. The insulated conductor
may then be braided or wrapped with tape soaked in Stockholm tar or other
preparation adapted to preserve the gutta-percha from atmospheric influences and
to protect it from injury by rough handling.
Dated the 27th day of June 1893.
G. G. M. HARDINGHAM.
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 abroad from the Firm
of Felten & Guilleaume, of Mülheim-on-the-Rhine, in the German Empire, Cable
Manufacturers,) 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 (and especially subterranean cables) for
use with alternating currents of low tension.
A cable constructed according to this invention is represented in transverse
section in Fig. 1 of the accompanying drawings; Fig. 2 showing a similar cable
containing flexible concentric conductors.
b is a tubular conductor composed of a series of wires of special cross section
arranged in a circle about a central air-space a and twisted together so as to retain
one another in position. Each wire is wedge-, hook- or V-shaped in transverse
section, or is otherwise formed to interlock with its neighbours, as is well
understood in connection with the manufacture of armoured cables.
CD
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page_text: As compared with a tubular conductor in which the metal is continuous in a
circumferential direction, the improved method of construction hereinbefore
described affords greatly increased flexibility.
The
The tubular conductor b is or may be enclosed in a sheathing of paper c or other
insulating material, and with a view to protecting the latter from moisture a
coating of gutta-percha d is next applied. Unlike the usual lead coating, the
gutta-percha coating does not cause any retardation of the electric current.
insulated conductor may then be braided or wrapped with tape soaked in Stockholm
tar or other preparation adapted to preserve the gutta-percha from atmospheric
influences and to protect it from injury by rough handling.
Instead of a single tubular conductor b (Fig. 1), two or more concentric
tubes 6* b b (Fig. 2) of similar sectional structure may be employed. c¹ and c³ are
additional layers of insulating material.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I claim :-
1. An electric cable comprising a tubular conductor composed of a series of
wires of special cross section arranged about a central air-space and twisted
together so as to retain one another in position, a sheathing of paper or other
insulating material, and a coating of gutta-percha, substantially as herein
described.
2. In an electric cable, the employment of a tubular conductor composed of a
series of wires of special cross section arranged about a central air-space and twisted
together so as to retain one another in position, substantially as herein described.
3. An electric cable comprising concentric tubular conductors, each composed of
a series of wires of special cross section arranged about a central air-space and
twisted together so as to retain one another in position, substantially as herein
described.
Dated the 28th day of March 1894.
G. G. M. HARDINGHAM.