Improvements in Electrical Cut-outs.
Year: 1897

page_text: Date of Application, 6th Aug., 1897
Complete Specification Left, 6th May, 1898-Accepted, 16th July, 1898
PROVISIONAL SPECIFICATION.
Improvements in Electrical Cut-outs.
I, HUGO HIRST, of 69-71, Queen Victoria Street, in the City and County of
London, Electrical Engineer, do hereby declare the nature of this invention to
be as follows:-
My invention relates to certain improvements in electrical cut-outs and has
for its object the isolation of the point of fusion which takes place when an
excess of current passes through the fusible metal within the cut-out, said isola-
tion enclosing the vapor evolved by the fused metal and preventing an arc being
formed between the terminals of said cut-out, and also preventing the escape
of molten particles.
In carrying my invention into effect, I employ a base of china porcelain or
other suitable substance or material which may be of circular conformation,
this being one form of construction, said base having a hollow boss formed
upon it with two or more ribs or webs projecting radially therefrom.
The upper part of said boss is provided with a male screw thread so as to engage
with a corresponding screw in a domed cover, also of china, porcelain, or other
suitable material. The terminals are fixed upon opposite sides of the hollow
boss aforesaid and the fuse is led by means of holes or slots through the cavity
of the boss, the ribs or webs intervening between the terminals externally. The
upper part of the domed cover if required may be provided with a ventilating
orifice or orifices, so that when fusion takes place within the cavity aforesaid the
vapor resulting therefrom may quickly escape, but any metallic globules in a
state of fusion retained. This method of construction entirely confines the point
of fusion, and isolates it within the cavity of the boss, preventing the formation
of an arc between the terminals.
I may also construct the cut-out with a base so as to present a shorter screwed
boss for the retention of the domed cover, said boss having a rib or web across
it, and formed upon it through which the fuse passes. The terminals are partly
countersunk below the surface of the base, and the domed cover is formed with
an exterior annular groove in its lower face, to clear said terminals, a hollow
space or cavity above the screwed part covering the rib or web. The fusible
metal passes upwards through the boss, and rib or web between the terminals,
and the points of fusion are thus isolated on each side of the rib or web as
described in the former example, the difference being in, that instead of the cavity
being formed in the boss it is in this case formed in the cover.
In constructing circular cut-outs I may employ any number of radial ribs or
webs formed upon or attached to the base or boss, the fuse being carried through
holes or slots into an interior cavity, either directly or in a staggered direction,
and the point or points of fusion being thus isolated from the terminals by a
domed cover enclosing the whole.
In the case of constructing cut-outs of other than circular conformation for

page_text: single or multiple circuits I form upon or attach to the base certain rectangular
or diagonal ribs or webs, through which the fuse may be carried and staggered
as herein before described, one or more cavities being thus formed by the inter-
section of the ribs or webs, the cover may be countersunk to enclose said cavities
or may be flat to rest thereon and so to isolate the point or points of fusion from
the terminals when in place. I may use an enclosed or insulated bolt or set.
screw, bolts or setscrews for holding said cover in position.
I do not confine myself to any particular conformation of the covers, bases,
ribs or webs, provided that an isolated space or spaces is or are formed for the
prevention of au-arc between the terminals when the fuse is ruptured.
The material used in making the bases, covers and other insulating parts of
the cut-outs is preferably china or porcelain, but any refractory insulating material
may be employed.
Tlated 0.441
J
T 1
1007
FREDK. WALKER,
73, St. Stephen's Road, Upton Park, E., London,
Agent for the Applicant.
I, HUGO HIRST, of 69-71, Queen Victoria Street, in the City and County of
London, 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; -
My invention relates to certain improvements in electrical cut-outs, and has
for its object the isolation of the point of fusion which takes place when an
excess of current passes through the fusible metal within the cut-out, said isola-
tion enclosing the vapor evolved by the fused metal, and preventing a destruc-
tive arc being formed between the terminals of said cut-out, and also preventing
the escape of molten particles.
In order that my invention may be clearly understood, I have appended the
accompanying three sheets of drawings, in which Figure 1 represents a plan
view of one form of a single pole cut out, and Figure 2 is a sectional elevation
thereof. Figure 3, 4 and 6 are modifications thereof, and the plan views
Nos. 5 and 7 are rectangular bases arranged upon the same lines. Figure 8 is
a plan view of a double pole cut-out, and Figure 12 Sheet 3 is a modification
thereof. Figure 9 is a plan view of a double pole rectangular cut-out, and
Figure 10 is a sectional elevation of the cover thereof. Figure 11 is a forin
of single pole cut out specially arranged for use in conjunction with ceiling roses,
wall plug connections, and the like, and Figure 13 shows a type of fuse enclosed
in a suitable insulating box which may be adapted to any of the isolating chambers
of the modifications herein before referred to, or used separately, or attached to
the terminals of multiple fuse boards, and Figure 14 is a sectional plan of the
same. Similar letters of reference are used to indicate corresponding parts
throughout the several drawings.
In carrying my invention into effect I employ a base A of porcelain, or other
suitable substance or material which may be of circular conformation as in
Figures 1, 2, 3, 4, 6, 8, 11, and 12, or rectangular or oblong as shown by
Figures 5, 7 and 9. In Figure 1, said base A has a hollow boss B formed upon

page_text: it, with two or more ribs or webs a projecting radially therefrom (as in
Figures 3, 8, and 11.) The upper part of said boss B is provided with a male
screw thread fitting a domed cover C, Figure 2, also of china, porcelain or other
suitable material. The terminals t t are fixed upon opposite sides of the hollow
boss B aforesaid, and the fuse f is led by means of holes or slots through the cavity
of the boss B the ribs or webs a intervening between the terminals t t as shown.
The domed cover C, if required may be provided with a ventilating orifice or orifices,
so that when fusion takes place within the cavity of B the vapor resulting therefrom
may quickly escape, but any globules in a state of fusion are retained.
method of construction entirely confines the point of fusion and isolates it within
the inner space formed by the wall of the boss B, thus preventing the formation
of a destructive arc between the terminals i t'.
This
I may modify the construction by employing several radial ribs or webs a
to isolate the terminals t t as in Figure 3, or may form the isolating fuse chamber
between any pair of ribs or webs surrounded by a wall W, this arrangement
being specially applicable to ceiling roses and the like as shown by Figure 4.
Another modification is shown by the sectional elevation Figure 6, in which the
base A has a solid screwed boss b for holding the domed cover C, said boss
having a rib or web W across it, through or over which the fuse passes. The
terminals are partly countersunk below the surface of the base A, and the
domed cover C is formed with an annular groove c in its lower face to clear said
terminals and webs which are not shewn by the drawings. A hollow space
or cavity B above the screwed part covering the rib or web W, forms the isolating
chamber or chambers. The fuse f passes upwards through the boss b and through
or over the rib or web W, between the terminals tt', and the point of fusion is
thus isolated. In this case, the difference is in that the isolating cavity B is
formed by the cover instead of the base A as in the previous examples. This
especial construction is also applicable to cutouts of the rectangular or oblong type.
In constructing single pole cutouts of other than circular formation as in
Figure 5 I form upon or attach to said base A a rectangular wall a forming
an isolating chamber B, through which the fuse f may be carried. The ter-
minals are perfectly isolated, and a cover may be fitted thereon in the usual
manner. A modification of this device is shown by Figure 7 Sheet 2 in which
the fuse f is carried through a central wall W parting the isolating cavity into
two divisions B B¹.
In adapting my invention to double pole cutouts or double circuits, I may con-
struct a circular base A with a boss, as in Figures 1 and 2, but the interior
thereof divided into two isolated chambers B, B by a wall W, which also parts
the terminals t t T, T, Figures 8 and 12 and completely isolates the poles
and points of fusion. A rectangular cut out based upon the same lines is shown
by Figure 9 and Figure 10 is a sectional elevation of the cover thereof, showing
the grooves g which embrace the prolongation of the wall W to secure perfect
isolation.
I may enclose the fuse wire or strip f in a box B as shown in perspective by
Figure 13 Sheet 3, and in sectional plan by Figure 14. A cylindrical box of
paper or cardboard B, like a pill box, is lined with plaster or like refractory
material y leaving a hollow chamber w through which the fuse f passes, the ends
of which are connected to two connecting wires tt, which allow of attachment
to the terminals. When the fuse f is burnt out the whole may be thrown away,
and replaced by a fresh box, as the cost is small. This device may be used on
any circuit, or may be adapted to any of the isolated chamber cutouts hereinbefore
lescribed.
I do not confine myself to any particular conformation of the covers, bases,
ribs, webs, or boxes, nor the material or substance of which each or any part may
be formed.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is: 1-
First. The construction of cutouts for electrical circuits substantially as herein
described and shown.
Second. In cutouts for electrical circuits the provision of an isolating wall or
walls forming a chamber in which the fuse is melted substantially as herein
described and shown by the drawings.
Third. In cutouts for electrical circuits the provision of an isolating space or
spaces in which the fuse is melted with ribs or webs enclosing the terminals and
preventing the formation of a destructive arc, substantially as herein described
and shown by the drawings.
Fourth. In cut outs for electrical circuits the method of and means for arrang-
ing upon a base one or more interposing ribs or webs to isolate the terminals
substantially as herein described and shown by the drawings.
Fifth. In cutouts for electrical circuits the method of and means for enclosing
a fusible wire or strip within an isolating box, with terminal wires or strips so
that the whole may be readily renewed, substantially as herein described with
special reference to Figures 13 and 14 of the appended drawings.
Dated this 6th LV 1000
FREDK. WALKER,
73, St. Stephen's Road, Upton Park, London, E.,
Agent, for the Applicant.