Improvements in Electric Fuses for Mines and like purposes.
Year: 1894

page_text: Date of Application. 6th Oct., 1894
Complete Specification Left, 3rd July, 1895-Accepted; 20th July; 1895
PROVISIONAL SPECIFICATION.
Improvements in Electric Fuses for Mines and like purposes.
A communication by LA SOCIÉTÉ M. GAUPILLAT & Co., of 39 Rue Bouret,
Paris, in the Republic of France, Cartridge Manufacturers.
*I, WILLIAM' PHILLIPS THOMPSON, F.C.S. M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool and 6, Bank Street,
Manchester, both in the County of Lancaster and 323 High Holborn in the
County of Middlesex Civil Engineer, do hereby declare the nature of this
invention to be as follows:-
i
This invention relates to, an improved kind of fuse for mines and for like
purposes, the firing of which is effected by the passage of an electric current
between imperfect contacts arranged in the interior of the fuse, the resistance of
which causes a sufficient elevation of temperature to ignite the powder contained
in the said fuse.
It is well known that if an electric current be passed through two masses of
carbon or other conducting substances terminated by points slightly rounded and
arranged in contact in front of one another, the resistance experienced. by the
current causes a considerable elevation of the temperature at the point of contact
of these two points. The heat thus developed is utilised either by surrounding the
two heated points with any suitably iuflammable substance or by forming the two
points themselves of a substance which is both a conductor of electricity and
inflammable at a certain temperature.
The principle of the fuse being explained the means which must be employed to
allow of its being practically realised, will now be explained.
The fuse is formed of a small core of cardboard; pulp, wood or other insulating
substance in which two insulated conducting wires are fixed supplying the electric
current to the fuse. The two uncovered ends of these conducting wires extend a
few millimetres beyond the core, and are terminated by two little spatulas formed
simply by these wires being flattened.
In order to solidly fix the conducting wires, the core above named is terminated
by a kind of dish which is filled with wax. This prevents at the same time any
communication with the external air. The ends of the conducting wires are
terminated by two little spheres or ovoids of a substance which is a partial
conductor of electricity and also partially inflammable and these two spheres or
ovoids enclose the spatulas, above mentioned and are approached one to the other
until they touch, and they are maintained in this position by the tension of the two
conducting wires themselves which act as springs and are with this object slightly
bent in the desired direction in order to maintain the two spheres in contact. It is
of course understood that any suitable substance either pure or composed of various
mixtures, may be employed to form these little spheres or blocks.
The fuse thus prepared is inserted in a casing tube or envelope in which it is
solidly fixed by means of a bezil. (groove and flange). This tubo - contains
internally a small quantity of inflammable powder which surrounds the two spheres
and remains in close contact with them.
Finally a little plug provided with a gold beater's skin is inserted in the 'casing
tube as far as the point where it is stopped by a circular internal projection formed
in the tube.

page_text: The fuse such as has just been described. serves for firing blasting holes charged
with ordinary powder. When it is a question of blasting by means of dynamite or
other explosives necessitating the use of a cap or detonator, this latter is placed at
the end of the casing tube, either in the, inside, or outside and is fixed in this
position by any suitable setting.
When the wires of the fuse herein before described are placed in communication
with a source of electricity, the current will encounter a great resistance in passing
through the imperfect.contact existing between the two spheres, and consequently
this part will become heated and will cause the ignition of the two spheres, which
will communicate: the flame to the powder surrounding them, the effect of which
will be to project a jet of flame through the hole arranged in the plug hereinbefore
named, either into the powder in the blast hole or onto the fulminate of the
detonator.
.
"
It is evident that this kind of fuse may be arranged in several different ways,
for instance:
.
A. The fuse may be formed of a single sphere interposed between, the two
conducting wires for the current; in this arrangement the current passes through
the imperfect and resisting contacts.
B. The spheres may be replaced by a fine point of semi-conducting and
semi-inflammable substances, which point strikes on, a little block of the same
substance.
C. The two spheres may be arranged so as not to adhere to the conducting
wires and only be held by two sorts of spoons formed at the ends of these wires.
In all these cases the conducting wires instead of being, fixed as usual in a flexible
cable. may be simply placed either in the interior or on the exterior of a wooden
ring fitted on the base of the casing of the fuse:
Dated this 5th day of October 1894.
COMPLETE SPECIFICATION.
Improvements in Electric Fuses for Mines and-like purposes..
A communication by LA SOCIÉTÉ. M. GAURILLAT & Co., of 39 Rue Bouret,
Paris, in the Republic of France, Cartridge Manufacturers.
1, WILLIAM PHILLIPS. THOMPSON. F.C.S., M.1.M.E., of The Agency. fer
Foreign Patent Solicitors, 6,, Lord Street, Liverpool and 6 Bank Street,
Manchester both in the County of Lancaster, 118 New Street, Birmingham in
the County of Warwick, and, 31 High Holborn in the County of Middlesex,
Civil 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
·
嘉
This invention relates to, an improved kind of fuse for mines and for like
purposes, the firing, of, which, is effected by tho passage of an electric current
between imperfect contacts arranged in the interior of the fuse, the resistance of
which causes a sufficient elevation of temperature to ignite the powder contained
in the said fuse.
The invention will now be described with reference to the accompanying drawing,
on which,
Figure 1 shows the principle on which the invention is founded-;;
Figure, 2 is a longitudinal section of a fuse formed in conformity with this
invention;
Figure 3 is an outside view of the same fuse

page_text: Figures 4, 5, 6 and 7 are vertical sections of various modifications of this fuse.
It is well known that if an electric current circulating in two conductors D
and D be passed through two masses of carbon A and B or other conduoting
substances, terminated by points C slightly rounded and arranged in. contact in
front of one another, as shown in Figure 1, the resistance experienced by the
current causes a considerable elevation of the temperature at the point of contact
of these two points. The heat thus developed is utilised either by surrounding
the two heated points with any suitable inflammable substance or by forming, the
two points themselves of a substance which is both a conductor of electricity and
inflammable at a certain temperature.
The principle of the fuse being explained, the means which must be employed to
allow of its being practically realised, will now be explained.
The fuse, Figures 2 and 3, is formed of a small hollow core A of cardboard,
pulp, wood or other insulating substance in which two insulated conducting wires B
and B' are fixed supplying the electric current to the fuse.. The two uncovered
ends of these, conducting wires extend a few millimetres beyond the core, and
are terminated by two little spatulas formed simply by these wires being
flattened.
In order to solidly fix the conducting wires B and B₁ the core A above named
is terminated by a kind of dish E which is filled with wax. This prevents at the
same time any communication with the external air. The ends of the conducting
wires B B are terminated by two little spheres or ovoids F F¹ of a substance
which is a partial conductor of electricity, and also partially inflammable and
these two spheres or ovoids enclose the spatulas above mentioned, and, are
approached one to the other until they touch, and they are maintained in this
position by the tension of the two conducting wires B and B themselves which
act as springs, and are with this object, slightly, bent in the desired direction in
order to maintain the two spheres in contact. It is of course, understood that any
suitable substance either pure or composed of various - mixtures, may be employed
to form these little spheres or blocks.
The fuse thus prepared is inserted in a casing tube or envelope G in which it is
solidly fixed by means, of a bezil (groove and flange).. This tube G.contains
internally a small quantity of inflammable, powder H, which surrounds the two
spheres and F and remains in close contact with them.
Finally, a little plug provided with a gold beater's skin is inserted in the
casing tube G as far as the point K where it is stopped by a circular internal
projection L formed in the tube..
The fuse such as, just been described, serves. for firing blasting holes charged
with ordinary, powder. When it is a question, of blasting, by means of dynamite
or other explosives necessitating the use of, a cap or detonator, this latter is placed
at the end of the casing tube, either in, the inside or outside, and is fixed in this
Position by any, suitable means.
When the wires B B of the fuse hereinbefore described, are placed in com-
munication with a source of electricity, the current will encounter a great
resistance in passing through the imperfect contact existing between the two
spheres Fand and consequently this part will become heated and will cause
the ignition of the two spheres, which will communicate the flame to the powder
surrounding them, the effect of which will be to project a jet of flame through the
hole arranged in the plug, hereinbefore named, either into the powder in the blast
hole or onto the fulminate of the detonator.
It is evident that this kind of fuso may be arranged in several different ways, for
instance :-
In the arrangement shown in Figure 4, the fuse may be formed of a single
sphere interposed between the two conducting wires for the current ; in this
arrangement the current passes through the imperfect and resisting contacts L"
and Lu
In the arrangement shown in Figure 6, the spheres may be replaced by a fine

page_text: point M of semi-conducting, and semi-inflammable substances, which point, strikes
on a little block N of the same substance.
In the arrangement shown in Figure 6, the two spheres may be arranged so as
not to adhere to the conducting wires' and only be held by two sorts of spoons
formed at the ends of these wires. In all these cases the, conducting wires B B¹
instead of being fixed as usual in a flexible cable may be simply placed, either in
the interior, or on the exterior of a wooden ring O, Figure 7, fitted on the base of
the casing of the fuse.
'
'
The following, are some examples of the mixtures which may be employed' for
forming the semi-conducting and semi-inflammable spheres or blocks hereinbefore
mentioned...
$1
Chlorate of potash
Sulphuret of antimony'
Rotort carbon.
5 parts by weight.
- 5- "
20
"'
:
SECOND EXAMPLE:
Chlorate of potash,
10 parts by weight.
Sulphuret of antimony,
"
"
Sulphuret of copper.
10
{" 99. :39+
In these mixtures or compounds the object of the chlorate of potash is merely to
furnish the oxygen necessary for the combustion.
'The substances are mixed and moistened whilst cold with water containing a
solution of gum or other suitable material; in order to obtain a thick liquid in
which the flattened ends of the conducting wires having the form of spatulas are
immersed, and it is only necessary to suspend these conductors in the open air or
in a stove in order to dry the drop of liquid adhering thereto, which by capillary
action assumes a spherical form. In order to obtain balls or spheres, which do not
adhere to the conductors the operation is performed in the same manner as that for
the manufacture of granular powders or dragées for instance.
"
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to .
me by my foreign correspondents, I declare that, what I claim is :-;
In electric fuses for mines and like purposes, the ignition of which 'fuses" is
brought about by the heat caused by the passage of an electric current between
imperfect contacts arranged in the interior of the fuse, the forming of the said
contacts of inflammable or non-inflammable' substances, which are good' or bad
conductors of electricity, in spheres, ovoids, points or blocks, arranged on the ends
of the conducting wires of the fuse, substantially as herein before described and
shown' on the accompanying drawing.
A