Improvements in Combined Joint or Service Boxes and Fuse-boxes for Concentric and other Electric Cables.
Year: 1899

page_text: Date of Application, 24th Apr, 1899-Accepted, 10th June, 1899
COMPLETE SPECIFICATION.
Improvements in Combined Joint or Service Boxes and Fuse-boxes
for Concentric and other Electric Cables.
We, ALLAN JOHN LAWSON, JOSEPH GERSHOM CHILDS, and JAMES DOUGLAS
DALLAS, of Moorgate Court, Moorgate Place, in the City of London, Electrical
Engineers, 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 relates to improvements in combined joint or service boxes and
fuse boxes or cut-outs for concentric or other cables:
According to the invention we provide a metal case, preferably of cast iron,
lined internally with a suitable insulating material such as vulcanized fibre or
enamel so as to render the case water-tight. A partition of vulcanized fibre or
other suitable insulating material divides the box into two compartments adapted
to receive respectively the positive and negative poles or terminals. In the case
of a concentric cable the said cable passes through a hole in the case into one
compartment, and the outer conductor is electrically connected to the terminals
thereof, whilst the inner conductor passes through a hole in the partition into
the other compartment, the said hole in the partition being completely closed up
to prevent the passage of any gases at this point from one compartment to the
other.
A hole is provided in the partition at a point remote from the supply terminal
to enable any explosive gas or vapour, which may be generated on the blowing of
a fuse, to escape from the fuse compartment into the other compartment and thence
through a hole in the case into the atmosphere.
The fuse is advantageously enclosed in a tube of suitable material preferably an
insulating material such as vulcanized fibre for subduing or choking the arc.
This tube is closed at its bottom end to prevent the spread of the flame in that.
direction should the fuse melt, and also to break the arc formed on the melting
of the fuse by the violent expulsion of the air contained in the tube, which air
is expanded by the heat developed.
To enable the invention to be fully understood we will describe it by reference
to the accompanying drawings, in which:-
Figure 1 is a vertical section through the outer compartment of a combined
service box and fuse-box for a concentric cable constructed according to the inven-
tion.
Figure 2 is a similar section through the inner or fuse compartment:
Figure 3 is a cross section on the line 3-3 Figure 1 with certain parts removed;
and
Figure 4 is a plan view of the service box with the cover removed.
a is the case of the box and a¹ the lid thereof; the said box a is lined internally
with a layer b of insulating material, such for example as vulcanized fibre or
enamel, and we advantageously provide a gasket or packing of suitable material

page_text: between the lid a¹ and case a; c is the parition which divides the said box a
into two compartments d, e.
The compartment d is arranged to receive the outer (or negative) terminals d¹, &
and the compartment e the inner (or positive) terminals e',, e, the said terminals
being secured in the box in the ordinary way. The cable is introduced through
the lateral hole d³ into the compartment d, (the said hole d³ being provided with
a packing-box d) and then passes to the terminal d' in which it is clamped. The
inner conductor is continued through the hole c¹ in the partition c closing the said
hole tightly and thence to the terminal e¹ in the compartment e; the two house
conductors issue from the two compartments through the tubular insulating
pieces d³, c³ respectively let into holes in the front end of the case a in the ordinary
manner.
The terminals d', d³ are connected in the usual way by the bar do adapted to be
sprung into the spring contacts do, do which are fitted to the terminals d', d.
The terminals e¹, e³ are also provided with contacts e, e to receive the fuse, the
said fuse being, however, advantageously surrounded by a tube f of suitable
material such for example as vulcanized fibre or other suitable insulating material
so as to subdue or choke the arc. The bottom of the tube f is closed by a metal
plug f¹ so as to prevent the spread of the flame downwards in the event of a fuse
melting. This plug f' has a hole formed through it to receive the fuse (not
shewn in the drawing), the said hole being closed by a screw f³ when the fuse has
been placed in position.
g, h are holes formed respectively in the partition c and in the outer wall of
the compartment & for enabling any explosive gases or vapours which may be
formed on the blowing of a fuse to pass from the compartment é into the atmosphere.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
1. A combined joint or service box and fuse-box for concentric or other cables
comprising an insulated metal case or box divided by a partition into two com-
partments adapted to receive the two poles respectively and into which the two
conductors pass, substantially as, and for the purpose, hereinbefore described.
2. A combined joint or service box and fuse-box for concentric cables of the
kind described in Claim 1 wherein the cable enters the outer compartment and
the inner conductor passes through a hole in the partition, the said hole being
tightly closed, substantially as, and for the purpose, hereinbefore described.
3. In a combined service box and fuse-box of the kind described in Claim 1
the employment of a tube surrounding the fuse, the said tube being closed at the
bottom, substantially as, and for the purpose, herein before described.
4. A combined joint or service box and fuse-box, constructed substantially as
herein before described and illustrated in the accompanying drawings.
Dated the 94th dov of Aunil 1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicants.