Improvements in or connected with Electric Cable Disconnecting Boxes.
Year: 1896

page_text: Date of Application, 28th Nov., 1896-Accepted, 16th Jan., 1897
COMPLETE SPECIFICATION.
Improvements in or connected with Electric Cable Disconnecting
Boxes.
We, GEORGE HINDE NISBETT, of "Ashfield" Huyton, in the County of
Lancaster, Electrical Engineer, and WILLIAM BOBY of 16 Union Court,
London, 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 following statement :-
This invention has reference to disconnecting boxes used in connection with
electric cables, and more particularly, cables conveying high tension currents of
electricity, for electric lighting, power, or heating; and it has amongst other
things for its object, mainly to provide improvements whereby the disconnection of
a main can be rapidly and effectually performed, without, or with a minimum, of
risk to the operator.
The improvements the subject of this invention, are involved in the construc-
tion of box and parts shewn in the drawings hereto annexed, and, will be set forth
in the description thereof; the novel features or characteristics constituting such
improvements being pointed out or specified in the claims concluding the
specification.
In the drawings, Figure 1 is a longitudinal sectional elevation, Figure 2 is a
plan with cover removed, and Figure 3 a cross section at A A Figure 1, of a
disconnecting box according to this invention; while Figure 4 is a detail of handle
used in connection with the apparatus.
Referring to the drawings, the box proper is designated a, which, in the case
shewn, is of rectangular form and of metal-say cast iron-having on the opposite
side or end the necks a', through which the ends of the cables b are introduced,
the cable, in the case shewn, being of twin form. Within the box a there are four
metallic terminals c, two on either side for the two cable ends which are to be
connected and disconnected. The terminals c rest upon and are fixed to a base
plate, d, of insulating material, such as ebonite, porcelain, or other suitable
material; and this plate is supported or carried upon insulating blocks e from the
bottom of the cast-iron box a, it being held down upon same by the central
screw d. By this arrangement and construction a high insulating resistance is
obtained.
The terminals c are separated from the sides of the box a on all sides by
arranging or disposing sanie a substantial distance from the walls of the box, and
also from one another; and they are also further separated by walls fof insulating
material, supported upon the base plate d, and disposed in between the sides of the
box a and the terminals and parts connected with them, and also by division
walls of suitable insulating material, which separate the terminals one from
another. Thus each terminal lies within a well or box, formed by the walls or
partitions referred to.
The opposite terminals c are normally connected by links g, consisting of plates
connected together at their upper portions, as shewn, while their lower ends fit
over and in contact with the sides of the termiuals c as shewn. The links g are
carried up in arched form so as to enable high partitions f¹ to be used; while both
these partitions, and the walls f, are of such a height, and so arranged, that when
the links g are opened, and an are is formed on breaking the circuit, this are can
neither reach the side of the box, nor extend from one terminal to the other.

page_text: Normally, when the terminals are connected, the space within the walls ƒ in
which the links g are placed, is closed above by a shield or cover h of insulating
material, this shield or cover h having a hole in it over the centres of each of the
links g.
д
For effecting the removal of a link g and disconnecting the terminals c, the
handle shewn in Figure 4 is used. This handle i is made of or insulated by
suitable insulating material, and is provided at the lifting end with a screw j, and
above this point with a large flange k. This loose handle is, in action, passed
through one of the holes in the shield h, and having its point entered into the
tapped hole, by turning it the screw j enters and engages with the link. When
it has been screwed down to the proper position, the link g can be lifted out, and
the cover then serves as a shield, whereby the accidental contact of persons and
with any "live" metal, either in closing or opening the connections, is effectually
prevented; the arc also is prevented from reaching the haud when the circuit is
broken. Then, as to the flange k of the handle i, this also acts as a shield, and
tends to prevent the hand coming in contact with any "live" metal.
With regard to the enclosure of the box a, the construction or means according
to this invention, and shewn in the drawings, consists in making the cover with a
pendent vertical portion ', which acts as hereafter described; and also in providing
the case a with two troughs m m', oue below the other, which are filled with heavy
oil, tallow, or the like, in which the lips 12 13 of the cover l fit as shewn, by which a
double seal or attachment of the cover with the case is effected. By this
construction, the air between the two lutes or seals is imprisoned; and by the
double seal the entrance of moisture into the chamber is rendered difficult. And
moreover, by the imprisonment of air and by the pendent overhanging part 1, the
cover acts as a diving bell; and even in the event of the box being submerged,
the entrance of water to the chamber over the top of the casing a would be
prevented by the resistance of the imprisoned air.
It is to be stated that the improvements connected with the terminals of the box
described, are not dependent on the form of cover described, although this is the
form of cover preferred; but the ordinary cover bolted down the usual way could
be used, if desired. Further, in the drawing, the box is constructed and adapted
for a twin cable, but with simple modifications, it will be obvious, it can be used
for concentric cables, single cables, or other types of cables or conduits.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In an electric cable disconnecting box, an insulating shield (ash) adapted to
be left in place covering the connections when they are made, and to be removed
with such connections when they are removed; substantially as and for the
purposes described.
2. In connection with an electric cable disconnecting box, the employment of an
insulated disconnecting or loose handle i with a shield at its lower part, and
adapted to be operated and used substantially as and for the purposes described.
3. The general construction and combination of parts for connecting and
disconnecting electric cable terminals, particularly as set forth with reference to
and shewn in the drawings.
4. In a disconnecting box for electric cables, the construction of cover and box
substantially as described, by which the box is closed and sealed, and rendered
water tight.
Dated this 27th day of November 1896.
CHEESBROUGH & ROYSTON,
15 Water Street, Liverpool, Applicants' Patent Agents.