IMPROVEMENTS IN ELECTRIC TELEGRAPH TERMINAL AND SHACKLE INSULATORS
Year: 1879

page_text: LETTERS PATENT to Charles Edwin Crighton, of Newcastle upon Tyne,
Mechanical Engineer, for the Invention of "IMPROVEMENTS IN ELECTRIC
TELEGRAPH TERMINAL AND SHACKLE INSULATORS."
Sealed the 9th April 1880, and dated the 16th October 1879.
PROVISIONAL SPECIFICATION left by the said Charles Edwin Orighton at
the Office of the Commissioners of Patents on the 16th October 1879.
CHARLES EDWIN CRIGHTON, of Newcastle upon Tyne, Mechanical Engineer.
"IMPROVEMENTS IN ELECTRIC TELEGRAPH TERMINAL AND SHACKLE INSULATORS."
My Invention has for its object the production of a terminal or shackle insulator
so constructed as to render the insulation of electricity more perfect than is
attainable by the insulators at present used for terminating and shackling the
telegraph wires of aerial lines.
In carrying out my Invention as applied, for example, to the construction of a
terminal insulator in order to effect the object before mentioned, I form the
insulator in the following manner :-
To the horizontal arm carried by the telegraph post I attach an insulating hollow
conical body by means of a metal encircling strap and bolts, around which body I
place another insulating body or shed which partially encloses the former and is
attached thereto by cement or otherwise. Through the centre of these parts so
combined passes a conducting rod or bolt for forming the connection between the
subterraneous and the aerial wires and receiving the strain of the latter. This rod
or bolt is screw threaded at one end for the reception of a conical protuberance or
plug adapted to a similarly shaped aperture in the central body and at this end is
the point of junction with the subterraneous wire, the extremity of the central
body being closed with a screw cap enclosing the end of the bolt and the joint and
leaving an orifice of a sufficient size only for the passage of the subterraneous wire.
The plug on the rod or bolt, which may be composed of any suitable material, is
provided with washers or rings of india rubber or other similar elastic material, so
as to form a cushion or yielding body under the strain exerted by the aerial wire.
To the opposite end of the bolt to that at which the subterraneous wire is attached,
is connected the aerial wire, the connection being made in the usual manner. The

page_text: central body is provided upon a portion of its length with alternate annular or
surrounding recesses and projections, the object being to retard the passage of rain
or moisture from the conducting rod or bolt to the strap which attaches the
insulator proper to the horizontal arm. Thus the entry or passage of rain or
moisture is first intercepted by the external insulating body or shed, but should it
gain access to the interior by the rod or bolt, the moisture has to traverse the
annular undulations of the central insulating body and escape from the other end
of the external insulating body or shed, before it can arrive at the attaching strap
so that the continuity of damp or moisture and liability of the electricity escaping
to earth through the rod or bolt and the strap is obviated or greatly diminshed.
The horizontal arm is grooved or recessed throughout its length on the under-
side for the passage of the subterraneous wire, and is covered by a lid so as to
completely protect and enclose the wire.
In the case of shackle insulators the apparatus is constructed in substantially a
similar manner with the exception that as no connection with a subterraneous
wire is required, the bolt and its appurtenances are modified as will be well
understood.

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 16th
April 1880.
CHARLES EDWIN CRIGHTON, of Newcastle upon Tyne, Mechanical Engineer.
"IMPROVEMENTS IN ELECTRIC TELEGRAPH TERMINAL AND SHACKLE INSULATORS."
My said Invention has for its object the production of a terminal or shackle
insulator so constructed as to render the insulation of electricity more perfect than
is attainable by the insulators at present used for terminating and shackling the
telegraph wires of aerial lines.
In carrying out my said Invention as applied, for example, to the construction of
a terminal insulator in order to effect the object before mentioned, I form the
insulator in the following manner, reference being had to the several Figures on
the Sheet of Drawings hereunto annexed :—
Figure 1 of the accompanying Drawings represents a longitudinal section of a
terminal insulator constructed according to my anid Invention; Figure 2 is a plan,
and Figure
an end view of the same, both corresponding to Figure 1.
To the horizontal arm A, carried by the telegraph post B, I attach an insulating
hollow conical body C by means of a metal encircling strap D and bolts E, around
which body I place another insulating body or shed F, which partially encloses the
former (C) and is attached thereto by cement or otherwise. Through the centre of
these parts so combined passes a conducting rod or bolt G for forming the
connection between the subterraneous wire H and the aerial wire I and receiving
the strain of the latter. This rod or bolt is screw threaded at its end a for the
reception of a conical protuberence or plug K, adapted to a similarly shaped
aperture in the central body C, and at this end is the point of junction 6 with the
subterraneous wire H, the extremity of the central body C being 'closed with a
screw cap M, enclosing the end a of the bolt G and the joints at band leaving an
orifice at c of a sufficient size only for the passage of the subterraneous wire H.
The plug K, which may be composed of any suitable material, is provided with
washers or rings d, d, of india-rubber or other similar elastic material, so as to form
cushions or yielding bodies under the strain exerted by the aerial wire I. To the
end a¹ of the bolt opposite to the end a at which the subterraneous wire H is
attached, is connected the aerial wire I, the connection being made in the usual
manner. The central body C is provided upon a portion of its length with
alternate annular or surrounding recesses e and projections f, the object being to
retard the passage of rain or moisture from the conducting rod or bolt G to the
strap D, which attaches the insulator proper to the horizontal arm A. Thus the
entry or passage of rain or moisture is first intercepted by the external insulating
body or shed F, but should it gain access to the interior by the rod or bolt G, the
moisture has to traverse the annular undulations e, f, of the central insulating body
Cand escape from the other end of the external insulating body or shed F before
it can arrive at the attaching strap D, so that the continuity of damp or moisture
and liability of the electricity escaping to earth through the rod or bolt G and the
strap D is obviated or greatly diminished.
The horizontal arm Å is grooved or recessed throughout its length on the under-
side, as shewn at g, for the passage of the subterraneous wire H and is covered on
the underside by a lid N so as to completely protect and enclose the wire.
In the case of shackle insulators the apparatus is constructed in substantially a
similar manner with the exception that as no connection with a subterraneous wire
is required, the bolt and its appurtenances are modified as will be well understood.
Having now described and particularly ascertained the nature of my said
Invention 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,

page_text: and therefore claim as the Invention secured to me by the hercinbefore in part
recited Letters Patent is,-
First. In a terminal insulator forming the connection between the subterraneous
wire and the aerial wire in the interior of the insulator, substantially as herein-
before described.
Secondly. In a terminal or shackle insulator the combination of an insulating
hollow body conical on its interior and exterior, a metal encircling strap with
attaching bolts or connections to a telegraph arm, and an internal conical plug for
receiving the strain of the aerial wire, substantially as herein before described.
Thirdly. In a terminal or shackle insulator, the employment of an insulating
hollow conical body enclosing a conducting rod or bolt for receiving the strain of
the aerial wire, the said hollow conical body having alternate annular or surrounding
recesses and projections for preventing the continuity of damp, substantially as
herein before described.
Fourthly. The general arrangement and combination of parts forming a terminal
or shackle insulator, substantially as and for the purposes hereinbefore described.
In witness whereof, I, the said Charles Edwin Crighton, have to this my
Specification set my haud and seal, this Ninth day of April, One thousand
eight hundred and eighty.
ARYATMANT