IMPROVEMENTS IN MEANS OR. APPARATUS EMPLOYED FOR ELECTRICAL FIRING, AND IN FUZES FOR THE SAME
Year: 1879

page_text: LETTERS PATENT to Samuel Joseph Mackie, of 23, Southampton Buildings, in
the County of Middlesex, for the Invention of "IMPROVEMENTS IN MEANS OR.
APPARATUS EMPLOYED FOR ELECTRICAL FIRING, AND IN FUZES FOR THE
SAME."
Sealed the 9th March 1880, and dated the 13th September 1879.
PROVISIONAL SPECIFICATION left by the said Samuel Joseph Mackie at the
Office of the Commissioners of Patents on the 13th September 1879.
SAMUEL JOSEPH MACKIE, of 23, Southampton Buildings, in the County of
Middlesex. " IMPROVEMENTS IN MEANS OR APPARATUS EMPLOYED FOR ELECTRICAL
FIRING, AND IN FUZES FOR THE SAME."
Hitherto the firing of electrical fuzes in blasting and other opèrations has been
performed by joining the fuzes in circuit, in which case the electric spark or current
was intended to jump or pass the whole series simultaneously. In practice through
the differences in the resistance of the individual fuzes and from other causes
intermediate obstructions take place and frequent failures occur.
To avoid such failures, and to make certain of discharging every fuze in a series
of any number I use a leading wire to each of the fuzes in the series, and in each
leading wire I make a break; and bridge the same at. the instant of firing by a
moveable contact maker operated in any desired manner.
Or the break of continuity may be made either in the leading or return wire, or
in both, and the contact at time of firing may be made by a moving or falling
weight, disc, slide, bar, screw, or other mechanical means.
The apparatus I have employed and found to answer consists of a battery and
induction-coil with an inclined bar of brass connected with the leading pole of the
induction coil. Upon this brass bar a metal carriage runs freely, the bar being
inclined at an angle. To the insulated support of the bar there are attached at
short intervals, the insulated wires leading to the fuzes, the ends of these wires.
being in contact with metal studs which are consecutively touched by a spring or
contact-maker carried by the metal carriage as it travels along the metal bar. At
each consecutive contact the full force of the current from the induction-coil passes
in succession through each of the fuzes, and insures the ignition of the fuze powder;
or if the fuze or its connections is defective the missfire is confined to the defective
fuze, and does not interfere with the discharge of the others in a series which may
Dias 11

page_text: be practically unlimited, so that any number whatever of fuzes may be fired by one
electrical instrument.
The metal bar may be placed vertically and the carriage or weight allowed to
fall perpendicularly.
The discharge of the fuzes may be also made by short circuiting the currents to
earth successively.
The leading wires may be protected from injury by the discharge of stones in
blasting or otherwise by being enclosed in piping, and the ends of the respective
leading wires in such case are brought out laterally through T pieces; the branch-
wires leading to the charge-holes are secured to insulated plugs which screw into
the T pieces, and the ends of the fuze wires are secured the one to the branch wire
stud and the other to the piping which constitutes a metal conductor for the return
current.
The leading or branch-wire may be continued any distance beyond the T pieces,
and the fuze wire attached to an insulated terminal, and the return current may be
brought to earth or be carried by a separate wire or by a wire protected within the
piping.
In lieu of piping I, according to my Invention, prefer to use a partial tube of C
section, and to use split T pieces.
My improved fuze consists of two parallel insulated metal wires secured by a
plug cast or mechanically fastened round them. The plug is inserted in a soft
metal cap containing the fuze powder, and the two are secured together by shellac
or other cementing material to form an air tight and water tight joint. The cap
may be, if preferred, nipped on to the end of the plug or to the end of a double
wire cord by proper pliers; in this way, by means of a tube and sliding clip, I form
a permanent fuze, to which a fresh fuze-powder cap can be attached after every
firing, the fuze being merely placed in the mouth of the pricker-hole leading to the
charge or connected to the end of a special fuze, which may be formed of gun-
cotton strands served with tarred tape or other material, or may consist of a tube
filled with powder, dynamite, or other explosive.
For firing from a distance I hold the metal carriage before mentioned by an
induced magnet, and liberate the same at the time of firing by breaking the contact
of the battery with the soft iron core of the magnet, or such may be effected by
clockwork or other mechanical means.
The discharge of the fuzes may, by the above means, be made with exceeding
rapidity in the form of an almost instantaneous volley, or they may be inde-
pendently fired by keys or other means so as to suit special arrangements of
explosive charges, guns, torpedoes, rockets, or fireworks, or for telegraphing, light-
house and signalling purposes, every desired arrangement or combination of
discharge being practicable.
The latter mode of firing is effected by the employment of secondary terminal
wires, which are put in special connection, as desired, with the coil current by
switches or keys without forming part of the general series. These only will be
fired when the moving contact-maker passes over them.
The soft metal cap enables the fuze to be made non-detonative, in which case the
fuze is serviceable for the discharge of gunpowder; but if the charge to be fired be
dynamite, gun-cotton, or other explosive requiring detonation the soft metal cap
can be inserted in the detonator when required, and the fuzes can be previously
stored with safety.
According to my Invention I prefer to make the permanent fuze of two metal
plates or discs separated by a thin plate of ebonite or other non-conductor, or one
wire may be brought within a metal tube, and separated from it by an intermediate
non-conducting ring.
In either of these fuses the distance for the jump or transmission of the electric
spark or current may be regulated as desired, and uniformity attained in any
number of fuzes manufactured.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Samuel Joseph Mackie in the Great Seal Patent Office on the 13th
March 1880.
"
SAMUEL JOSEPH MACKIE, of 23, Southampton Buildings, in the County of
Middlesex. IMPROVEMENTS IN MEANS OR APPARATUS EMPLOYED FOR ELECTRICAL
FIRING, AND IN FUZES FOR THE SAME."
Hitherto the firing of electrical fuzes in blasting and other operations has been
performed by joining the fuzes in circuit, in which case the electric spark or current
was intended to jump or pass the whole series simultaneously. In practice through
differences in the resistance of the individual fuzes and from other causes in-
termediate obstructions take place and frequent failures occur. To avoid such
failures and to make certain of discharging every fuze in a series of any number,
I use a leading wire to each of the fuzes in the series, and in each leading wire I
make a break, and bridge the same at the instant of firing by a moveable contact
maker operated in any desired manner.
The break of continuity may however be made either in the leading or return
wire or in both; and the contact at time of firing may be made by a moving or
falling weight disc, slide bar, screw or other mechanical means.
The apparatus I have employed and found to answer consists of a battery and
induction coil with an inclined bar of brass connected with the leading pole of the
induction coil.
Upon this brass bar a metal carriage runs freely, the bar being inclined at an
angle.
To the insulated support of the bar there are attached at short intervals the
insulated wires leading to the fuzes; the ends of these wires being in contact with
metal studs which are consecutively touched by a spring or contact maker carried
by the metal carriage as it travels 'along the metal bar. At each consecutive
contact the full force of the current from the induction coil passes in succession
through each of the fuzes and insures the ignition of the fuze powder; or if the
fuze or its connections is defective, the misfire is confined to the defective fuze
and does not interfere with the discharge of the others in a series which may be
practically unlimited, so that any number whatever of fuzes may be fired by one
electrical instrument. The metal bar may be placed vertically and the carriage or
weight ailowed to fall perpendicularly. The discharge of the fuzes may be also
made by short circuiting the currents to earth successively. The leading wires
may be protected from injury by the discharge of stones in blasting or otherwise,
by being enclosed in piping, and the ends of the respective leading wires in such
case are brought out laterally through T pieces; the branch wires leading to the
charge holes are secured to insulated plugs which screw into the T pieces, and
the ends of the fuze wires are secured the one to the branch wire stud, and the
other to the piping which constitutes a metal conductor for the return current.
The leading or branch wire may be continued any distance beyond the T pieces
and the fuze wire attached to an insulated terminal, and the return current may
be brought to earth or be carried by a separate wire or by a wire protected within
the piping.
In lieu of piping I according to my Invention prefer to use a partial tube of C
section and to use split T pieces.
For firing from a distance I hold the metal carriage before mentioned by an
induced magnet and liberate the same at the time of firing by breaking the contact
of the battery with the soft iron core of the magnet, or such may be effected by
clockwork or other mechanical means.
The discharge of the fuzes may by the above means be made with exceeding
rapidity in the form of an almost instantaneous volley; or they may be inde-

page_text: pendently fired by keys or other means so as to suit special arrangements of
explosive charges, guns, torpedoes, rockets, or fireworks, or for telegraphing, light-
house and signalling purposes, every desired arrangement or combination of discharge
being practicable. The latter mode of firing is effected by the employment of
secondary terminal wires, which are put in special connection as desired with the
coil current by switches or keys without forming part of the general series. These
only will be fired when the moving contact maker passes over them.
Diagram, Figure 1, represents one method of carrying this part of my Invention
into effect. This diagram represents the apparatus at one of my firing stations
enclosed in its case. M is the induced magnet supplied with the electric current
from the distant head station A. The moveable contact maker T is held by
its armature K to the magnet M so long as the electric current passes, but when
this current is cut off the contact maker T is liberated and runs rapidly down the
metal rail R on the inclined tram F, making contact sucessively with the studs 8, 8,
8, s, by means of the spring D. The metal rail R is in connection with one pole of
the Rhumkorff coil P by the wire w, and stud n.
Each of the studs 8, 8, 8, 8, is
the terminal of an insulated leading wire w³, w¹, w, w', which leads direct to each of
the fuzes employed in the blasting or other operation. The action of the apparatus
is as follows. When contact is made between the moveable contact maker T and
the terminal studs 8, 8, 8, 8, the current passes from the rail R through the contact
maker T, and thence by the spring D and leading wires w¹ through the fuze to the
return wire N1, and thence to the opposite pole N of the coil P. The coil P is
served by the batteries B¹, B¹¹, B¹¹¹.
The various wires w¹ leading to the fuzes are gathered into a cable or bundle and
may be protected from injury by the discharge of stones in blasting or otherwise
by being enclosed in protecting pipes I, and the ends of the respective leading
wires in such case are brought out laterally through T pieces I¹. The branch
wires w¹ leading to the fuzes f, in the charge holes or in the firing tubes are secured
to insulated plugs I" which screw or slide into the T pieces and the ends of
the leading wires w¹, and the return wires w² are secured the one (w¹) to the leading
or branch wire stud 8, the other (w²) to the piping I, which constitutes together with
the wire N¹¹ a metal conductor for the return current.
The leading or branch wires w³ may be continued any distance beyond the T pieces,
and the fuze wires may be attached to an insulated terminal, or the return current
from the fuse may be brought to earth, or be carried by a separate wire, or by a
wire protected within the piping as will be readily understood.
In lieu of employing ordinary piping I, I according to my Invention prefer to
use a partial tube of C section, as shown at Figure 2, and to use split T pieces in
order to facilitate the introduction therein of the wires.
At Figures 3 and 4 I have represented a modification of the arrangement shown
Figure 1, whereby the fuzes may be fired in any desired consecutive order, any one
or more of the fuzes being cut out of or inserted in the series by means of a key or
switch v, the leading wire w¹ in such case being divided and the two adjacent ends
thereof connected to an insulated bar v' upon which the switch or key is mounted,
with capability of being turned into position for connecting or disconnecting the
two adjacent ends of the wire was before described.
At Figure 5 I have represented another modification, in which the rail R is a
bar of nonconducting material, and the current from the coil P is by the wire w
transmitted to the stud s¹ and thence passes through the spring T₁ and carriage T,
and through the spring T2 and studs to the leading wire w¹.
At Figures 6 and 7 I have represented another modification in which the carriage T
runs upon a guide rod Ts, and the lower surface of which slides upon smooth
ways formed of alternate pieces of conducting and non conducting material 8, s', and
respectively; the current in this case passing from the coil P, through the wires w,
conducting pieces s', to the carriage T, and thence by the conducting pieces s to the
leading wires w¹.
At Figure 8 I have represented an arrangement in which the moveable contact

page_text: maker consists of springs T1, T2, carried by a weighted bar T, and coupled together
either by cross pieces T3 insulated from the bar T; or, if the bar T be itself insulated,
T¹².
it may form the coupling means for the springs T",
The bar T and contact maker in this case falling in a vertical direction.
The wires w from the coil P are connected to the studs s¹, and the leading wires w
are connected to the studs s; the passage of the current being through the various
parts as before described.
At Figure 9 a somewhat similar arrangement of parts is shown, but in that shown
at Figure 8 the studs 8, 8¹, are shown to project beyond the inner face of a tube and
to be provided with inclined faces to form a check to the too sudden descent of the
contact maker, whilst in the arrangement shown at Figure 9 the studs 8, 81, are flush
with the inner face of the said tube, and the contact pieces T1, T2, are forced outwards
by strong springs T.
8
At Figure 10 I have represented another modification, in which the studs s are
arranged in a circle and a weighted bar T mounted on an axis carries the contact
makers T, T%, such bar T being in connection with the coil P, each of the leading
wires w being connected to two of the studs s on opposite sides of the dial, so that
in their course the contact makers T', T2, make double contact with each leading
wire w to prevent a mis-fire with any of the fuzes.
In the arrangements shown at Figures 8, 9, and 10 the weighted bars are held
up until liberated by a magnet M as described with respect to Figure 1, or clock-
work or other mechanical means may be employed for this purpose in any of the
arrangements herein described, and the contact maker may be caused to run down
by its own weight, or mechanical means may be employed to effect this object.
In any of the arrangements herein described secondary terminal wires w¹ may be
employed in combination with switches or keys v for cutting out or bringing into
the general series any of the wires w or w³ as described with respect to Figures 3
and 4.
•
My improved fuze consists of two parallel insulated metal wires secured by a plug
cast or mechanically fastened round them. The plug is inserted in a soft metal cap
containing the fuze powder, and the two are secured together by shellac or other
cementing material to form an air tight and water tight joint. The cap may be if
preferred nipped on to the end of the plug, or to the end of a double wire cord by
proper pliers; in this way by means of a tube and sliding clip.
I form a permanent fuse to which a fresh fuze power cap can be attached after
every firing, the fuze being merely placed in the mouth of the pricker hole leading.
to the charge, or connected to the end of a special fuze which may be formed of gun
cotton strands served with tarred tape or other material, or may consist of a tube
filled with powder, dynamite, or other explosive.
The soft metal cap enables the fuze to be made non-detonative, in which case the
fuze is serviceable for the discharge of gunpowder; but if the charge to be fired be
dynamite, gun cotton, or other explosive requiring detonation the soft metal cap
can be inserted in the detonator when required and the fuzes can be previously
stored with safety. According to my Invention I prefer to make the permanent
fuze of two metal plates or discs separated by a thin plate of ebonite or other non-
conductor; or one wire may be brought within a metal tube and separated from it
by an intermediate non conducting ring. In either of these fuzes the distance for
the jump or transmission of the electric spark or current may be regulated as.
desired, and uniformity.attained in any number of fuzes manufactured.
At Figures 11 to 16 I have represented some of my improved fuzes, all of which
are drawn to an enlarged scale.
The fuze represented at Figure 11 consists of two parallel insulated wires 1, 1,
secured by a plug 2. cast, cemented, or mechanically fastened round them. The
plug 2 is inserted in a soft metal cap 3 containing the fuze powder 4, and the plug 2
and cap 3 are preferably secured together by shellac or other cementing material to.
form an air tight and water.tight joint. The cap 3. may if preferred be nipped on

page_text: to the end of the plug 2, or on to the end of a cord 5 containing two insulated wires 1, 1,
by proper pliers, or otherwise fastened thereto as represented at Figure 12.
The soft metal cap 3 enables the fuze to be made non-detonative, in which case
the fuze is serviceable for the discharge of gunpowder, but if the charge to be fired
be dynamite, gun cotton, or other explosive requiring detonation the soft metal cap 3
çan be inserted as represented at Figure 12 in a detonator 6 when required, and the
fuzes can be previously stored with safety; in this way, and by inserting the cord 5
in a tube 7, as shown at Figures 13, 14, 15, I form a permanent fuze to which a
fresh fuze powder cap 3 can be attached after every firing, the fuze being merely
placed in the mouth of the pricker hole leading to the charge 8 as shown at Figure 16,
or in the mouth of a tube 12 leading to the charge 8, as shown at Figure 19, or it
may be connected to the end of a special fuze formed as shown at Figure 17, of gun
cotton strands 9 served with tarred tape or other material 10 and hemp serving 11,
or it may consist of a tube 12 filled with powder, dynamite, or other explosive, or
down which the electrical fuze may be carried as shown at Figure 18.
According to my Invention I prefer to make the permanent fuze of two metal
plates or discs 13, 14, separated by a thin plate or disc 15 of ebonite or other non
conductor as shown at Figure 15, the current passing along the wire 1 to the
plate 13 jumps to the plate 14, and in its course explodes the piece of furze
powder 16, the current thence returns by the pipe 7. The explosion of the fuze
powder breaks or melts the plate 14 and thus discharges the fuze powder 4, the
latter being held in place in the tube 7 by a plug 17.
Or one wire 1 may, as shown at Figure 13, be brought within a metal tube 7
and separated from it by an intermediate non conducting material 5.
In either of these fuzes the distance for the jump or transmission of the electric a
spark or current may be regulated as desired and uniformity attained in any
number of fuzes manufactured.
The operation of my improved electrical firing apparatus is as follows:-When
the current is cut off from the magnet M, the metal carriage T or contact maker is
liberated, and runs swiftly down the inclined plane or falls vertically and in
doing so makes contact with the series of metal studs or terminals 8, 8', to one
of which (8) the wires leading to the fuzes are attached. If the coil P be properly
adjusted, it will start into action as soon as the contact maker is in connection
with the first stud 8 or 8¹, or the firing current can be brought to the firing station
by a separate wire from a battery in the engine house or at a station A either
above ground or some distance away from the blasting operations in a mine.
At Figure 1 is indicated the general system upon which my Invention is
proposed to be worked. During the working hours of the respective gangs, the
bore holes are all made and charged, and before the time of shift the fuze wires of
the respective series are coupled up to their respective leading wires. Some short
time previous to the appointed time of firing, the current to the magnet M is turned
on, in order that the armature of the contact maker may be adjusted against such
magnet; the workmen then leave the mine, the apparatus being now ready for
firing the charges, the senior foreman or "blasting master" reports to the engine
driver, or to the electrician, as the case may be, that the firing stations are all
properly set, the current is then cut off from the magnet M, and the contact makers
of the various local firing stations all simultaneously fall, thereby exploding the
respective charges.
The foremen of the incoming gangs soon after descend and see whether all the
charges have been duly fired; and if anything be amiss they work the respective 5
local firing stations accordingly and discharge any shots which from want of
coupling up, or other cause might remain unfired.
The workmen follow after a short interval and proceed in a similar way to the
former gangs. Thus the actual firing will take place when the mine is devoid of
human life.
I would here remark that the means or apparatus, and fuzes employed in elec-
5

page_text: trical firing, as herein described may be used for the discharge of blasting charges,
sound signals, guns, rockets, and for other purposes.
Having thus described the nature of my said Invention, and the mode in which
I carry the same into effect, I would have it understood that what I claim is,―
First. Using a leading wire to each electrical fuze in a series and making a break
in either the leading or return wire, and bridging the same by means of a
moveable contact maker in manner and for the purpose substantially as herein
shown and described.
Second. The employment of induced magnets, clockwork, or other mechanical
means for the distant liberation of the moveable contact maker substatially as
herein shown and described and for the purpose stated.
Third. The selection of charges for explosion by means of keys or switches
substantially as herein shown and described.
Fourth. The means of protecting the leading wires substantially as herein shown
and described and for the purpose stated.
Fifth. The use of partial tubes of C section for protecting the leading wires
substantially as herein shown and described.
Sixth. The improvements in electrical fuzes substantially as herein shown and
described.
Seventh. The use in combination with electrical fuzes of a soft metal cap for
insertion into detonators, firing tubes, guns, or otherwise, substantially as herein
shown and described.
-
Eighth. The production of a permanent electrical fuze by surrounding an
insulated wire with a metal tube substantially as shown and described.
Ninth. The employment in combination with an electrical fuze of a gun cotton
fuze to communicate fire or detonation to the charge or charges substantially as
herein shown and described.
Tenth. The employment of metal tubes in the bore holes to protect the
electrical wires of the fuze or to convey the flash of the fuze to the charge
substantially as herein shown and described.
In witness whereof, I, the said Samuel Joseph Mackie, have hereunto set my
hand and seal, this Twelfth day of March, in the year of our Lord One
thousand eight hundred and eighty.
TANK
SAMUEL JOSEPH MACKIE. (L.S.)