Improvements in Electrical Safety Fuses or Cut-outs."
Year: 1898

page_text: Date of Application, 5th July, 1898
Compinto Snocification loft 22nd Feb
1000
Accented
20th Ann 1000
PROVISIONAL SPECIFICATION.
Improvements in Electrical Safety Fuses or
Cut-outs."
I, WILLIAM EDWARD LANGDON, Electrical Engineer to the Midland Railway
Company, Derby, do hereby declare the nature of this invention to be as
follow:.
In the provision of an improved means of obviating the effects of leakage
or short circuit between any two or other wires forming the circuit, cr means of
supply of electric energy, whether employed for lighting or other purposes.
To this end I provide for the wire metal foil or other form of fuse being
enclosed in a block formed of an insulating medium in such a manner that there
shall be as little as possible air space, or space which may be filled with air,
enclosed within the chamber or the cover of the apparatus or part forming the
safety fuse appliance.
I do this under the assumption that that which causes the explosion and
consequent frequent rupture of such safety-fuse appliances is the sudden
expansion of air within the same, on the inrush of current through the safety
fuse consequent upon the short circuiting of the portion of the electric service
which it is required to protect, and that consequently if the safety fuse is
embedded in a suitable material or so arranged within a cover that the air
is as far as possible excluded, there will be little air to expand and the destruction
of the fuse will take place without being attended with that explosive report
and disruption of the device which now arises.
±
I accordingly carry the safety fuse through or in a groove apperture or hole
provided for its reception in a block of insulating material, and I provide a
close fitting cover to the same where necessary; or I enclose the fuse within a
groove between two blocks of insulating material one of which may be grooved
or pierced for the purpose of forming an outlet for the molten matter when the
fuse becomes melted or disrupted.
121 1
1000
I, WILLIAM EDWARD LANGDON, Electrical Engineer, Midland Railway, Derby,
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:-
In the provision of an improved means of obviating the effects of leakage or

page_text: short-circuit between any two or other wires forming the circuit or means of
supply of electric energy whether employed for lighting or other purposes.
To this end 1 provide for the wire, metal foil, or other form of safety fuse
being enclosed in a block formed of an insulating medium in such a manner
that there shall be as little as possible air space, or space which may be filled
with air, enclosed within the chamber or the cover of the apparatus or part
forming the safety fuse or appliance.
In illustration hereof rig. 1 represents in horizontal section a circular form of
fuse block of which Fig. 2 is a vertical section and Fig. 3 a perspective view of
same with cover. A is a block of insulating material, such as porcelain, recessed
at C for the reception of the circuit connections. Passing from C to C¹ (Figs.1
and 2) this block is perforated by a small channel D), sufficiently large to accept
the wire, metal strip, or other form of the material forming the safety fuse
required to be inserted between the metal clamps or terminals shewn at
C and C. The base of the block A is, at d d', immediately below these terminal
plates, pierced for the reception of the "leads" which connect the fuse with the
service wire and the block is also pierced as required for the reception of the
fixing screws, as at gg. The upper portion of this block, as shewn in the vertical
section, I enclose by means of a cover B, which may be screwed on or fastened
in any other manner so long as it is effectual in excluding, as much as is possible,
the air from the neighbourhood of the fuse.
Fig. 4 shews in partial cross section and Fig. 5 in plan, another arrangement
for effecting the same end. A is the fuse block, recessed at BB for the binding
plates and for the reception of the block D (Fig. 4), C is a metal foil forming
the fuse, D (Fig.4) a block of insulating material fitting the recessed plane of A 2
so as to fill the space enclosed by the cover E when, in position. This cover may
be screwed on or confined by other means, and the block in this, as in the
previous case, may be round, rectangular, or any required shape.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what 3
I claim is:
First. A safety-fuse block, the solid portion of which is pierced by a channel
sufficiently large for the reception of the safety fuse but which shall otherwise
exclude, as far as is possible, the air from the neighbourhood of the fuse
substantially as described and set forth in the text and illustrated by Figures 3
I. II. III.
Second. A safety fuse block composed of two or more parts arranged to so
fit the one part with the other as to exclude, as far as is possible, air from_the
neighbourhood of the safety fuse substantially as described and set forth in the
text and illustrated by Figures 4 and 5.
Dated this 20th day of Wah 1000
4
WILLIAM EDWD. LANGDON.