Improvements in Fusible Cut-out or Safety Devices for Electric Conductors.
Year: 1895

page_text: Date of Application, 4th Oct., 1895
Complete Specification Left, 6th July, 1896-Accepted, 8th Aug.. 1896
PROVISIONAL SPECIFICATION.
Improvements in Fusible Cut-out or Safety Devices for Electric
Conductors.
We, GERALD WILLIAM PARTRIDGE, of 25ª Cockspur Street, Charing Cross,
London, S.W., Civil Engineer, and ARTHUR FRANCIS BERRY, of Manor House,
Ashley, Market Harborough, in the County of Leicester, Electrical Engineer,
do hereby declare the nature of this invention to be as follows:-
This invention has reference to fusible cut-out or safety devices suitable for
electric conductors through which high tension currents flow and has for its objects
to provide a high degree of insulation such as is essential in cases where one pole
of the system is at the same potential as the earth and the fusible cut-out is on the
insulated pole; to keep separate and cover the several fuse wires to isolate them as
far as practicable from the external air or from an appreciable body of air, with the
view of obviating corrosion or liability to explosions of a character likely to
fracture the fuse box, and likewise (in the event of fusion) to obviate the mainten-
ance of an electric arc consequent upon the resulting fumes to absorb the heat
generated in the fuse wires and cause it to be distributed over the base as
uniformly as practicable; and to provide in a simple and efficient way for the
drainage of moisture from the fuse box; at the same time presenting every facility
of easy inspection and renewals. For the purpose indicated the fuse wires are
imprisoned between strips of suitable insulating material such as mica one resting
on the porcelain or other base which forms or may form the bottom of the fuse box-
the other resting on top of the fuse wires. Sometimes there may also be introduced
some suitable insulating and isolating substance such as shellac varnish between
the wires and between the mica strips, so that the wires will be the more closely
surrounded and isolated.
In order that pressure may be distributed as evenly as possible over the mica
sheets so as to bring them into close mutual contact there is provided above them
an elastic cover and above this elastic cover is placed a lid of insulating material
adapted by its weight to load the elastic cover sufficiently to afford the necessary
pressure against the mica, or other insulating material used. The elastic cover
may advantageously be made of vulcanized india rubber which will adapt itself to
the irregularities of the mica and after a time owing to contact with air will become
hard and maintain its shape. Vent holes are or may be provided for escape of air
from the fuse box.
In order that moisture may readily run out of the fuse box and that within a
given length of box a greater length of base surface may be afforded than in
ordinary constructions, the base is made of an arched or rounded shape supported
on a corrugated pillar which is or may be such that it can be conveniently supported
by a bracket projecting from a wall or otherwise. At each end of the curved base
there is a metal socket piece; to these the respective portions of the electric main
or conductor are electrically connected. The sockets are adapted to receive and
form electrical connection with plugs to which the ends of the fuse wires are
attached.

page_text: Improvements in Fusible Cut-out or Safety Devices for Electric
Conductors.
We, GERALD WILLIAM PARTRIDGE, of 25ª Cockspur Street, Charing Cross,
London, S. W., Civil Engineer, and ARTHUR FRANCIS BERRY, of Manor House,
Ashley, Market Harborough, in the County of Leicester, 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 following
statement :-
This invention has reference to fusible cut-out or safety devices suitable for
electric conductors through which high tension currents flow, and has for its objects
to provide a high degree of insulation such as is essential in cases where one pole
of the system is at the same potential as the earth and the fusible cut-out is on the
insulated pole; to keep separate and cover the several fuse wires so as to isolate
them as far as practicable from the external air or from an appreciable body of
air, with the view of obviating corrosion or liability to explosions of a character
likely to fracture the fuse box, and likewise (in the event of fusion) to obviate the
maintenance of an electric are consequent upon the resulting fumes; to absorb the
heat generated in the fuse wires and cause it to be distributed over the base as
uniformly as practicable, and to provide in a simple and efficient way for the
drainage of moisture from the fuse box, at the same time presenting every facility
of easy inspection and renewals. For the purpose indicated the fusible cut-out or
safety device is constructed as we shall now describe with reference to the
accompanying drawing in which
Fig. 1 shows partly in end elevation and partly in cross section, a fusible cut-out
according to this invention, the two parts of the fuse box being shown moved
apart.
Fig. 2 is a view of the inner side of the part of the fuse box carrying the
terminals to which the respective portions of the electric main or conluctor are
connected, and Fig. 3 is a similar view of the other part of the fuse box carrying
the fuse wires.
Fig. 4 is a cross section on the line of Fig. 1.
1. 1 are the fuse wires connected at their ends to brass or other mecal washers 2
placed upon metal plugs 3 the heads 3 of which are fixed at suitable distances
apart in a porcelain or other insulating base piece 4 which may be made of
channelled section as shown. The fuse wires which may obviously be replaced by
one or more metal strips, which is or are their equivalent, are imprisoned between
strips 5, 5 of suitable insulating material such as mica, one of which (5) rests
against the porcelain or other base piece 4 between the washers 2 and the
other (5) is perforated or slotted at the ends to receive the plugs 3 and rests on
top of the fuse wires. Sometimes there may also be introduced some suitable
insulating and isolating substance, such as shellac-varnish, between the wires and
between the mica strips, so that the wires will be the more closely surrounded and
isolated.
In order that pressure may be distributed - evenly as possible over the
mica strips so as to bring them into close mutual contact at the edges,
and it may be between the wires, there is provided above or against them
an elastic cover 6 and above or against this elastic cover is placed a lid 7
of insulating material adapted to load the elastic cover sufficiently to afford the
necessary pressure against the mics, or other insulating material used. The lid 7
is perforated or slotted at the ends to fit the plugs 3 and may act by its weight
to load the elastic cover 6 when the base 4 is arranged horizontally so as to form

page_text: the bottom of the fuse box; or the lid may be pressed against the said elastic
cover by nuts 8 screwed upon the plugs 3. The elastic cover may advantageously
be made of a strip of vulcanized india rubber which will adapt itself to the
irregularities of the mica and after a time, owing to contact with air, will become
hard and maintain its shape. 9 is a second base piece of porcelain or other
insulating material forming with the base piece 4, à fuse box. At each end of
and within the base piece 9 is secured a metal socket piece 10; to these the
respective portions of the electric main or conductor 11 are electrically connected.
The sockets are suitably adapted as for example by slotting them so as to form
spring fingers 10%, to receive and form electrical connection with the plugs 3 when
the base pieces 4 and 9 are brought together to place the fuse wires in circuit.
The base piece 9 may be provided with an extension 11 by which it can if desired
be supported, as for example on a bracket projecting from a wall, or otherwise.
This extension may advantageously have a corrugated exterior as shown to lessen
liability of leakage through moisture. For a like reason the surface of the base
piece 9 between the socket pieces 10 may be made of an arched or rounded shape
or be provided with transverse recesses 10°.
The base pieces 4 and 9 may be adapted to be variously held in position. In
the example shown, the base piece 9 is adapted to be supported in a vertical
position by its extension 11 and is formed at its lower end with a hook shaped
extension 12 adapted to receive and support the rounded end portion 13 of the
base piece 4 and form therewith a hinge-like joint adapted to permit of the said
base piece 4 being readily turned from its closed position, in an outward and
downward direction, as shown in Fig. 1, to allow of inspection or replacement of
the fuse wires 1, or of such base piece with fuse being removed bodily from the
base piece 9, lateral motion of the base piece 4 being prevented by side flanges 13ª.
The two base pieces 4 and 9 may be held together parallel with each other and so
that 4 partly encloses 9, by any suitable catch, such for example as a spring
catch 14 fixed to the base piece 9 and adapted to engage with a rounded exten-
sion 15 on the base piece 4. The fuse box may if desired, be provided with vent
holes for escape of air.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. A fusible cut-out or safety device for electric conductors wherein fuse wires
(or their equivalent) are imprisoned between strips of insulating material such as
mica one of which rests against a porcelain or other insulating base and the other
against the wires, and the said strips are pressed together by an elastic cover loaded
by a lid of insulating material, substantially as hereinbefore described for the
purpose specified.
2. Our improved fusible cat-out or safety device for electric conductors, con-
structed substantially as herein before described with reference to and shown in the
drawings-annomed.
Dated this 6th day of June 1896
Dated this 6th day of June 1896
For the Applicants,
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.