IMPROVEMENTS IN THE CONSTRUCTION OF ELECTRIC TELEGRAPH CABLES
Year: 1858

page_text: LETTERS PATENT to Lawrence Wood Fletcher, of Bleaklow, near Bury
in the County of Lancaster, Spinner and Manufacturer, for the. Invention
Of "IMPROVEMENTS IN THE CONSTRUCTION OF ELECTRIC TELEGRAPH CABLES."
Sealed the 14th May 1859, and dated the 4th December 1858.
PROVISIONAL SPECIFICATION left by the said Lawrence Wood Fletcher
at the Office of the Commissioners of Patents, with his Petition, on
the 4th December 1858.
I, LAWRENCE WOOD FLETCHER, of Bleaklow, near Bury, in the County of
Lancaster, Spinner and Manufacturer, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF ELECTRIC TELEGRAPH
CABLES," to be as follows."-
The nature of my Invention consists in so constructing electric telegraph
cables, that the wires through which the electric currents pass shall be pre-
vented from elongating by the covering wires. In performing my Invention,
the wires through which the electric currents pass are coated with gutta
percha in the ordinary manner. I prefer to coil these wires slightly either in
the same or in contrary directions, so that they may be elongated without
injury, but they may be longitudinal as now customary. The exterior of the
gutta percha is then surrounded with iron or other wires placed longitudinally
instead of spirally as now customary, or partly with wires and partly with
cords, and the whole is afterwards covered by lapping with wires or cords
saturated in tar or other suitable material, or by braiding or weaving.
The object of my Invention is to reduce the weight of telegraph cables, and
to prevent injury to the copper wires when a longitudinal strain is exerted on
the cable.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Lawrence Wood Fletcher in the Great Seal Patent Office
on the 4th June 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LAWRENCE
WOOD FLETCHER, of Bleaklow, near Bury, in the County of Lancaster, Spinner
and Manufacturer, send greeting.
WHEREAS Her. most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of December, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year
of Her reign, did, for Herself. Her heirs, and successors, give. and grant
unto me, the said Lawrence Wood Fletcher, Her special licence, that I
the said Lawrence Wood Fletcher, my executors, administrators, and assigns,
or such others as T. the said Lawrence Wood Fletcher, my executors.
administrators. and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make use. exercise, and vend, within
the United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF
ELECTRIC TELEGRAPH CABLES," upon the condition (amongst others) that I,
the said Lawrence Wood Fletcher, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands, and seals,
should particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Lawrence Wood Fletcher, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement (that is to say):-
In constructing electric telegraph cables, it has hitherto been customary to
cover the gutta percha or other insulating material which surrounds the con-
ducting wire or wires with spiral strands of iron wire. A cable so constructed
is liable to elongate when in a state of tension, and as the covering strands of
wire are capable of elongating more than the conducting wires, it is evident
that when such elongation does take place beyond the limits to which the con-
ducting wires can be safely elongated, the said conducting wires must be
injured. Now, the nature of my Invention consists in certain improved modes
of constructing electric telegraph cables, whereby the conducting wires shall be

page_text: prevented from being injuriously elongated by any elongation of the covering
wires.
Another part of my Invention consists in coiling or twisting the conducting
wire or the strand of conducting wires in contrary directions, so that when the
electric telegraph cable is in a state of tension, the said wires may be free to
elongate to a greater extent than the covering wires. This part of my
Invention is particularly applicable when the cables are covered with twisted
or laid wire strands in the ordinary manner as now in use.
Another part of my Invention consists in weaving a covering of fibrous
materials over the conducting wire or strand of conducting wires previously to
insulating such conducting wires by india-rubber, gutta perchá, or other suitable
materials.
Another part of my Invention consists in weaving a covering tube over the
insulated wire or wires; this woven covering may be made of wire warp and
a binding weft of hemp or other fibrous material, or the warps may be of
fibrous material with a binding weft of wire, or both warp and weft may be
partly of wire and partly of fibrous materials.
The last part of my Invention consists in covering the insulated core of
electric telegraph cables with woven strips or bands of a combination of wire
and. fibrous material, saturated or coated over with india-rubber or other
adhesive and suitable substance.
But that the nature of these my improvements and the means I adopt in
carrying the same into effect may be fully understood, I will proceed to describe
the accompanying Sheet of Drawings, reference being had to the figures and
letiers marked thereon.
Figure 1 represents part of a strand of conducting wires forming the inner
portion of an electric telegraph cable constructed according to my improve-
ments; Figure 2 is part of a telegraph cable representing three stages of its
construction, namely, the conducting wires are shewn at A; these wires are
coated with gutta percha or. india-rubber, or any other approved insulating
material, as shewn at B, and then the covering shewn at C is woven on;
Figure 3 is a transverse section of the complete cable.
In performing my Invention, the copper or other wires through which the
electric currents pass are coiled together alternately in contrary directions,
that is to say, the seven or other convenient number of wires forming the
strand are first coiled or twisted one or more turns to the right hand, and then
one or more turns to the left hand, and soon alternately throughout the length
of the cable. The amount of alternate twist given to the conducting wires
may be varied, providing a surplusage of elongating elasticity remains in them

page_text: after that in the bearing portion of the cable has been expended, the object
being to allow the strand to elongate without injuring the conducting power of
the wires, and also to allow such wires when elongated to resume their original
untwisted state as when first drawn. The machinery employed in twisting the
wires in contrary directions is somewhat similar to that required in twisting
them together in one direction, as now customary: but it is evident that the
direction of motion must be reversed as often as a change is required in the
twist of the strand. This may be accomplished by a mangel wheel and pinion
or other equivalent mechanical arrangement, and at every change in the
direction of motion the wires must be held. by pairs of travelling nippers at the
point where the change in direction takes place, until a second or third alter-
nate change of twist has been accomplished, so as to prevent the wires from
untwisting. When the strand of conducting wires has been thus prepared, it
is covered with a coating of gutta percha or india-rubber, or other suitable
insulating material in the usual manner, and then the outer covering is woven
on in the following manner:-The outer covering consists of seven or other
convenient number of iron or other metal wires placed at equal distances
apart and parallel to the axis of the cable. Between each pair of covering
wires, and in a line with them, are one or two or other number of cords of
fibrous material, and these cords and wires are united together and secured to
the insulated conducting wires by a weft cord, which is woven with the covering
wires and parallel cords, as shewn at C, in Figure 2. By this-mode of weaving
the covering on to the core of the cable the core is securely held by and con-
nected to the covering; and I would remark here, that the weft may pass over
and under each alternate warp cord or wire, as shewn, or it may be taken
over or under two or more warp cords or wires, as in twill weaving, if
preferred.
The machinery employed in weaving the outer covering is similar to that
for which Letters Patent in England were granted to me on the Twenty-third
of December, One thousand eight hundred and thirty-nine, or to that usually
employed in weaving hose pipes; the wires and cords and the insulating con-
ducting wires are passed simultaneously through the loom, while the weft cord
is woven into the wire and cord threads of the warp, and around the insulated
wires, the core of the cable answering the purpose of the stretcher described
in the Specification of the Patent granted to me as above referred to.
coating of gutta percha or marine glue, or other substance to render the cable
impervious to moisture, is or may be then applied, and the cords of fibrous
material may be saturated in tar or other similar material, either before or
after they are woven on to the core of the cable.
A

page_text: Figure 4 represents a piece of single conducting wire, which is twisted in
In this
contrary directions for the purpose described in reference to Figure 1.
view the part from E to F is twisted to the right hand, and that from F to G
to the left hand; the part from G to H is again twisted to the right hand,
and again another portion is twisted to the left. The wire is thus alternately
twisted in contrary directions throughout its length, so that when elongated by
tension it assumes a straight line entirely without twist, or in the condition of
wire when first drawn. Amongst other modes of producing a single wire so
twisted. a very simple one is to take two or more wires and twist them alter-
nately together as before described, and after they have passed the second or
third pair of nippers. the wires are allowed to separate from each other, and two
or more single wires, alternately twisted as required, are produced.
In
Figure represents a portion of a telegraph cable constructed according
to a modification of my Invention: Figure 6 is a section of the same.
Figure 5 the part marked A is the strand of conducting wires, as in Figures
1 and 2; this strand is surrounded by a covering of cotton or other fibrous
material shewn at I, which, is woven on in a loom similar to that referred to
in describing C in Figure 2. The object of this covering of fibrous material is
to give additional strength to the cable, and to allow the conducting wires
greater liberty to elongate; also to give more effect to the adhesion of the
insulating material, which adheres better to the fibrous material than to the
conducting wires, and therefore a more complete insulation of the conducting
wires is effected. When the coating of insulating material has been applied,
as shewn at J, the outer covering K is woven on; this outer covering is very
similar to that shewn in Figure 2, but in the present instance the covering
wires and cords forming the warp are woven spirally or slightly twisted or laid
round the insulated core, thereby increasing the flexibility of the cable.
When the warps are twisted or laid in a diagonal direction, it is necessary to
impart a slow rotary motion to the core of the cable during the weaving, and
to the complete cable when woven, the amount of rotary motion depending on
the lay given to the covering.
same.
Figure represents part of an electric telegraph cable constructed according
to another modification of my invention; Figure 8 is a section through the
This cable is shewn with nine conducting wires, but a greater or less
number may be combined in a similar manner. The conducting wires, after
being twisted in contrary directions, as shewn at Figure 1, but each strand
having only three wires, are insulated in the usual manner; they are then
surrounded by a coating of insulating material, and then the covering is woven
on. This covering consists of eleven or other suitable number of strands, each

page_text: of which is composed of three wires surrounded by fibrous material saturated
in tar or other substance to render it impervious to water; these strands form
the warp, and they are united by a binding weft of wire or fibrous material,
by which they are woven spirally round the insulated cable.
Figure 9 represents another of my improvements in the construction of
electric telegraph cables. A is the strand of conducting wires on to which the
covering L is woven; the warp threads of this covering are woven in a diagonal
and spiral direction instead of straight, as shewn at I in Figure 5. In this
case it is necessary to give a rotary motion to the strand during the weaving,
as described in reference to weaving the outer covering in Figure 5; the
coatings of india-rubber or other insulating material are then applied to the
spirally woven covering of the strand of conducting wires in the usual manner,
and then one or more strips of woven fabric, either coated with or saturated in
a solution of india-rubber or other adhesive material, or in its natural state, is
or are lapped around, as shewn at M, or a serving of hemp or other fibrous
material may be lapped round the insulated core in the usual manner.
When two or more strips of fabric are lapped on, care should be taken that
the joint of the outer strip covers the joint of the strip beneath it.
The cable thus formed is then covered by one or more layers of strips of a
woven fabric made of a combination of metallic wires and fibrous materials in
any proportion of the metal to fibre, either in the weft or warp, or both, that the
strength of the cable or the adhesiveness of the insulating material may
require.
In this Drawing the covering fabric shewn at N is a woven tape, the warp
threads of which are alternate linen and iron wire, the weft is of linen. This
tape is first saturated or coated on one side with indiarubber, or other
adhesive and protecting materials; it is then lapped or laid spirally round the
insulated cable, to which it adheres and gives strength and durability; this may
be afterwards coated with any substance to render it impervious to moisture.
The strips, tapes, or bands forming the covering may be woven in tapes of
the required width in a loom, such as is used for weaving small wares; or
the fabric may be woven in a broad sheet in common looms, and then covered
or saturated with the adhesive insulating material in the piece, and afterwards
cut into strips or tapes of the required width, either to form a straight
longitudinal tube, with a joining or joint parallel to the axis of the cable, or
for lapping, as before described, or for both if required, and which may be
afterwards coated with waterproof or protecting substance. The above will
form a very cheap, durable, and strong covering for the outside of electric
telegraph cables.

page_text: Another advantage resulting from my improvements in the construction of
electric telegraph cables is, that their specific gravity is reduced, and the
comparative strength is increased.
Having thus stated the nature of my Invention, and described the manner
of performing the same, I wish it to be understood that I do not limit myself
to the precise details herein-before described, nor do I claim to have invented
all the separate details referred to; but what I believe to be novel and
original, and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent, is,
First, the improved modes of constructing electric telegraph cables shewn
and described, whereby the conducting wires or strands of wires are rendered
incapable of being injuriously elongated by the elongation or stretching of the
covering.
Secondly, the twisting of the conducting wire or the strand of conducting
wires in contrary directions, as shewn and described in reference to Figures 1
and 4, for the purpose of allowing the same to elongate without injury.
Thirdly, the weaving of yarns or cords of fibrous materials over the con-
ducting wire or strand of wires, as shewn and described at I and L in
Figures 5 and 9.
Fourthly, the weaving of yarns or cords of fibrous material in combination
with wires, around, or to form the coverings of electric telegraph cables, as
shewn and described in reference to Figures 2, 5, and 9. or in any other con-
venient manner.
And, lastly, I claim the combination of any of the above improvements, or
the application of any one or more of the same to electric telegraph cables
that are otherwise constructed in the usual manner.
In witness whereof, I, the said Lawrence Wood Fletcher, have hereto
set my hand and seal, this Second day of June, in the year of our
Lord One thousand eight hundred and fifty-nine.
L. W. FLETCHER. (L.S.)