An Improved Manufacture of Flexible Electric Cable.
Year: 1889

page_text: Date of Application, 29th June, 1889
Complete Specification Left, 25th Mar., 1890-Accepted, 3rd May, 1890
PROVISIONAL SPECIFICATION.
An Improved Manufacture of Flexible Electric Cable.
I, WILLIAM ERNEST GRAY of Silvertown in the County of Essex, Electrical
Engineer, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to provide a strong flexible cable suitable for torpedo
cables and countermining use.
In practice, these cables are very liable to kink while being handled, the metal
sheathing, which is constructed not only for strength, but elasticity, being liable to open,
and to expose the core to damage.
In order to provide against this risk, I propose to make the cable in the follow-
ing--I provide a metallic core consisting of a bundle of fine copper wires slightly
twisted this I cover with insulating material, then braid over the insulating material
in the usual way. The cable thus far made I envelope in a flexible metallic sheathing
composed of, say, twelve strands of steel or iron wire, each strand being composed of,
say, seven wires, No. 20 gauge, specially compounded. This flexible sheathing I
cover with a suitable tape, and after coating this with a preservative compound,
I complete the cable by braiding upon it a strong covering of hemp or
jute.
This covering, while serving to keep everything in place, does not detract materially
from the flexibility of the cable, but allows of its easy manipulation, while the risk of
injury to the core is effectually removed.
Dated this 29th day of June 1889.
NEWTON & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION,
An Improved Manufacture of Flexible Electric Cable.
I, WILLIAM ERNEST GRAY, of Silvertown in the County of Essex, Electrical
Engineer, do hereby declare the nature of this invention and in what manner the same
is to be performed, to be particularly described and ascertained in and by the follow-
ing statement:-
The object of this invention is to provide a strong flexible cable suitable for torpedoes
and countermining uses.
In practice, these cables are very liable to kink while being handled. Moreover,
their metal sheathing, which is constructed not only for strength, but elasticity,
is liable to open, and to expose the core to damage.
In order to provide against these risks, I propose to make the cable in the manner
illustrated in the accompanying drawing.
Fig. 1 is a transverse section of the cable, drawn at about full size; and
Fig. 2 is a side view of the same with portions cut away to show the mode in which
the cable is built up, in order to secure strength and flexibility.
In these figures, a is a metallic core, consisting of a bundle of fine copper wires
slightly twisted; this is covered with insulating material b, composed, say, of vulcanized
india rubber in the usual way. Enclosing the insulated copper wires is a coating c
of hemp or jute, inade by braiding in the usual way.
The cable thus far made, I envelope in a flexible metallic sheathing d, which is shown
as composed of twelve strands of steel or iron wire. For the formation of these strands,
I take seven wires, say, of No. 20 gauge, coated by being passed through a bath of
gutta-percha compound, and these twist together to compose a strand, which
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page_text: although of equal strength to the strands heretofore employed for the like purpose
will be less resilient, and, therefore, less liable to kink.
The strands thus constructed, I lay together around the cable, as shown at d,
giving them a twist around the braided core, say, one turn for every seven inches in
length.
This lay of the strands will avoid any undue opening of the sheathing when the
cable is in use, but in order more completely to provide against this, I braid upon the
sheathing a strong covering of hemp or jute e, which will bring up the diameter of the
cable to about 0-770 of an inch, that being a size which I have found in practice to be
convenient for handling and to give good results.
This hempen or jute covering e, while serving to keep everything in place, does not
detract materially from the flexibility of the cable, but allows of its easy manipulation,
while the risk of injury to the core, by exposure, is effectually removed.
Having now particularly described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
The means above described for reducing the liability of electric cables to kink, and for
preventing the exposure of the covered core, without detracting from the flexibility of
the cable.
Dated this 25th day of March 1890.
NEWTON & SON,
Agents for the Applicant.
NEWTON & SON,
Agents for the Applicant.