IMPROVEMENTS IN ELECTRIC TELEGRAPH INSULATORS."
Year: 1878

page_text: LETTERS PATENT to Charles Edwin Crighton, of Newcastle upon Tyne,
Mechanical Engineer, for the Invention of "IMPROVEMENTS IN ELECTRIC
TELEGRAPH INSULATORS."
PROVISIONAL SPECIFICATION left by the said Charles Edwin Crighton at
the Office of the Commissioners of Patents on the 19th November 1878.
CHARLES EDWIN CRIGHTON, of Newcastle upon Tyne, Mechanical Engineer.
"IMPROVEMENTS IN ELECTRIC TELEGRAPH INSULATORS."
My Invention has for its object the production of an insulator so constructed as
to render the insulation of electricity more perfect than is attainable by the insu-
lators at present in use, and to reduce the cost of construction and maintenance of
the electric telegraph.
In carrying out my Invention in order to effect these objects I support the
telegraph wire on the centre of the insulator in lieu of at the side by wire lashings
as at present, and I form a slot or groove in the insulator for the reception of the
wire, which is retained in its place by a hood or cap screwed on, which protects the
seat of the wire from damp and wet. A wedge of pottery, gutta percha, or other
suitable material is employed, which fits into the groove and can be screwed down
by the hood or cap tight upon the wire, thus in cases of fracture preventing the
wire from becoming slack beyond the post where accident happens.
By the use of my Invention the following advantages are obtained, viz.:-
1st. Greater economy in manufacture, simplicity and lightness in construction,
combined with increased strength.
2nd More nerfect insulation.

page_text: 3rd. Great saving of labour, time, and expense in attaching telegraph wire from
post to post as compared with the present method, as no wire lashings or iron
guards would be required.
4th. Greater power of resisting any strain brought to bear on the wire by wind
or snow, from the wire having a direct bearing on the centre of the insulator.
5th. Dispensing with the wire lashings by means of which the telegraph wire is
at present tied to the insulator, and which provide such a large area for an escape
of the electric current through any flaw in the insulator or continuity of damp or
rain between the insulator and the post, and also enabling the telegraph wire to
have the least possible contact with the insulator, combined with perfect security
from disconnection and complete protection from weather and chafing.
The insulator may be composed of porcelain or any other suitable material.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Edwin Crighton in the Great Seal Patent Office on the
15th May 1879.
CHARLES EDWIN CRIGHTON, of Newcastle upon Tyne, Mechanical Engineer.
"IMPROVEMENTS IN ELECTRIC TELEGRAPH INSULATORS."
My said Invention has for its object the production of an insulator so constructed
as to render the insulation of electricity more perfect than is attainable with the
insulators at present in use, and to reduce the cost of construction and maintenance
of the electric telegraph.
In carrying out my said Invention in order to effect these objects I support the
telegraph wire on the centre of the insulator in lieu of by wire lashings at the side
as at present, and I form a slot or groove in the insulator for the reception of the
wire, which is retained in its place by a hood or cap screwed or clamped on, which
protects the seat of the wire from damp and wet. A wedge of pottery, gutta
percha, hard wood, or other suitable material is employed, which fits into the
groove, and can be screwed or fastened down by the hood or cap tightly upon the
wire, thus in cases of fracture preventing the wire from becoming slack beyond
the post where accident happens.
And in order that my said Invention may be fully understood, I shall now proceed
more particularly to describe the same, and for that purpose shall refer to the
two Figures on the annexed Sheet of Drawings, the saine letters of reference
indicating corresponding parts in both Figures.
Figures 1 and 2 of the accompanying Drawings represent vertical sections taken
the one at right angles to the other of an insulator constructed according to my said
Invention.
A is the insulator proper, composed of porcelain or other suitable material, and
carried upon a bolt or post B of iron (for example), to which the insulator is attached
by cement a or by screwing, or in any other convenient manner.
In the upper part of the insulator A at 6 I provide a vertical slot, which is
enlarged and extended at its lower part so as to form a horizontal aperture c through
the insulator approximating to a duplo-conoidal shape, the aperture forming a ridge
at its centred and diverging and expanding both vertically and laterally from that
point to the extremities e, e. In the aperture c is placed the telegraph wire C so as
to rest upon the central ridge or saddle d, above which wire there is inserted in the
slot at ba wedge or intermediate piece D, made by preference of a slightly arched
form on its under side, as shewn, so as to rest with its two ends upon the wire, and
when forced down by screwing on to the top of the insulator a hood or cap E to
tightly press upon the wire C and slightly bend the same over the central ridge d,
thereby securely connecting the telegraph wire to the insulator.
Holes are provided at f for the insertion of a spanner for the facility of turning
the hood or cap E.
It is obvious that in lieu of making the seat of the wire of a ridge shape and the
lower part of the wedge of an arched form, the seat may be made flat or concave,
and the corresponding portion of the wedge may be made of a counterpart flat or
convex form.
viz
By the use of my said Invention the following advantages are obtained,
First. Economy in manufacture, simplicity and lightness in construction, combined
with increased strength.
Second. Saving of labour, time, and expense in attaching telegraph wires from
post to post as compared with the present method, as no wire lashings, bindings, or
iron or other guards are required.
Third. Greater power of resisting any strain brought to bear on the wire by wind
or snow from the wire having a direct bearing on the centre of the insulator.

page_text: Fourth. More perfect insulation, both by dispensing with the wire lashings by
means of which the telegraph wire is at present tied to the insulator, and which
provide such a large area for an escape of the electric current through any flaw in
the insulator or continuity of damp or rain between the insulator and the post,
and by minimizing the contact surface of the telegraph wire with the insulator,
whilst at the same time perfect security from disconnection and complete protection
from weather and chafing are obtained.
Having now described and particularly ascertained the nature of my said Inven-
tion, and the manner in which the same is or may be used or carried into effect,
I would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,--
The combination in an insulator of a slot, groove, or aperture in the body of the
insulator proper for the reception of the telegraph wire, of a wedge or intermediate
piece for exercising pressure upon the said wire, and of a protecting hood or cap
tightening the wedge or intermediate piece, all substantially as herein before
described.
In witness whereof, I, the said Charles Edwin Crighton, have to this my
Specification set my hand and seal, the Thirteenth day of May, One thousand
eight hundred and seventy nine.
CHARLES E. CRIGHTON. (L.S.)'