Improvements in the Insulation of Electric Cables.
Year: 1895

page_text: Date of Application, 22nd Aug., 1895
Complete Specification Left. 19th May, 1896-Accepted, 20th June, 1896
Improvements in the Insulation of 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 and is designed to secure flexibility in
the insulation of the conductor, and thus to provide against rupture of the insulation
when the cable is bent.
In carrying out this invention, strips, bands or cords of fibre, such as cotton,
wool, hemp or jute, are first wound round the conductor in such a manner that
regular intervals of space are left between the convolutions. About the strip-
furnished conductor is laid a covering of insulating material, consisting of paper in
one or more thicknesses, or analogous insulating substance. A second winding of
strips, bands or cords, of fibre is then applied outside the insulating material; .the
convolutions of this winding occupying the spaces between those of the original
winding. By this method of construction, the insulating material becomes undula-
tory in form and flexible in character.
In the actual manufacture of a cable according to this invention, the two windings
of fibrous material and the intervening covering of paper, or other insulating
substance, are laid about the conductor simultaneously, and, if desired, concurrently
with the manufacture of the conductor itself.
When such a cable is subjected to flexure, the insulation on the inner side of the
bent portion packs closer, whilst that on the outer side, owing to its corrugated
form, is capable of adapting itself to the increased length.
Dated this 22nd day of August 1895
G. G. M. HARDINGHAM.
COMPLETE SPECIFICATION.
Improvements in the Insulation of Electric Cables.
I, GEORGE GATTON MELHUISH HARPINGHAM, 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 and is designed to secure flexibility in
the insulation of the conductor, and thus to provide against rupture of the insulation
when the cable is bent.
A. cable or conductor insulated according to the present invention is represented
in the accompanying drawing, the insulating material being shown partly in
elevation and partly in longitudinal section. Strips, bands or cords a of fibre, such
as cotton, wool, hemp, ramie or jute, are first wound round the conductor b in such
[Price 8d.1

page_text: a manner that regular intervals of space are left between the convolutions. About
this strip-furnished conductor is now laid a covering of insulating material c,
-consisting of paper, which may be in one or more thicknesses, or analogous insulating
substance. A second winding of strips, bands or cords a¹ of fibre, similar to the
strips a, is then applied outside the insulating material e; the convolutions of this
winding (a) together with the portions of the insulating material (c) overlain by
them, occupying the spaces between the convolutions of the original winding (a).
By this method of construction, the insulating material becomes corrugated spirally,
flexibility being thereby secured.
In the actual manufacture of a cable according to this invention, the two windings
of fibrous material a a¹ and the intervening covering of paper c, or other insulating
substance, are laid about the conductor simultaneously, and, if desired, concur-
rently with the manufacture of the conductor itself.
When such a cable is subjected to flexure, the insulation on the inner side of the
bent portion packs closer, whilst that on the outer side, owing to its corrugated
form, is capable of adapting itself to the increased length.
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. The improved method of insulating electric conductors substantially as herein
described, and consisting in winding about the conductor strips, bands or cords of
fibrous material, disposed in two series of convolutions, in conjunction with a covering
of insulating material, arranged inside and outside the alternate convolutions of the
fibrous material, so as to present a corrugated appearance.
2. In an electric cable, the combination, with the conductor b, of the inner and
outer windings a a¹ of fibrous material and the intervening serving of insulating
material c arranged inside and outside alternate convolutions of the windings a a¹,
substantially as and for the purpose set forth.
3. An electric cable or conductor furnished with insulating material arranged
inside and outside alternate convolutions of windings of fibrous material, substan-
tially as described with reference to the accompanying drawing.
Dated this 30th day of April 1896.
G. G. M. HARDINGHAM.