Improvements in or connected with Electric Sparking Devices, more particularly for Igniting Devices of Motors Operated by Explosive Mixtures.
Year: 1898

page_text: Date of Application (in the United Kingdom), 23rd Nov., 1898
Complete Specification Left, 23rd Nov., 1898-Accepted, 4th Feb., 1899
COMPLETE SPECIFICATION.
Improvements in or connected with Electric Sparking Devices,
more particularly for Igniting Devices of Motors Operated by
Explosive Mixtures.
We, EMILE HOUPIED and CHARLES VICTOR GIRARD, both of 16, Rue Royer-Collard,
Paris, in the Republic of France, Manufacturers, 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 :-
When it is desired to utilise the induction current of a Ruhnkorff coil for
producing a spark at given intervals, a vibrator is generally combined with the coil.
This vibrator is actuated by an electro-magnet arranged in the axis of the coil and
which attracts or repels the hammer owing to the intermittent cutting off of the
source of electricity, which suppression is produced by any suitable means. When
the inducing or primary current is furnished by a battery, this current is sufficiently
regular and continuous to itself produce a regular functioning of the trembler or
vibrator and consequently a regular formation of sparks at the terminals of the
connected wire. But the current of a dynamo or magneto-electric machine could not
be employed for this purpose, as the alternating or continuous current from such a
source has irregularities and interruptions in its production which necessarily affect
the operation of the vibrator. In any case the possibility of the use of a dynamo
or magneto-electric machine for the said purpose is of particular interest in the
case of lighting or igniting devices for explosive mixtures in motors, the transport
and the maintenance of the apparatus being much simpler than that of a
battery.
The arrangement which we have invented enables these advantages to be
obtained. It allows of the use of a suitable electric machine whether a magneto-
electric machine or a dynamo for the production at regular intervals of a spark at
the terminals of the wire connected with an induction coil. In principle we have
discarded the vibrator of the induction coil and we produce successive interruptions
in the current by means of an interrupter mounted in circuit on the generating
machine (magneto or dynamo) and actuated by a cam mounted directly on the shaft
of the said machine. Each time that the contact of the interrupter is broken by the
action of the cam a current is induced in the wire connected with the Rubmkorff
coil and consequently a spark is produced in the igniter mounted on the said
wire.

page_text: In the accompanying drawings, there is shown as an example an interrupter
combined with a magneto-electric machine of the Siemens type.
Figure 1 is an elevation of the whole of the apparatus arranged in a
wooden box S provided with a handle T by which to carry it.
A condenser C may
be arranged on the circuit and placed in an insulated compartment of the box S;
Figure is a plan view of the apparatus;
Figure 3 is an end view showing the interrupter in its position for breaking the
circuit and for producing current in the terminal wire or the wire connected with
the coil A.;
Figure 4 is a detail view showing the interrupter in the position of contact, that
is to say with the circuit closed.
The Ruhmkorff coil A is shown as mounted in the magnets p of the magneto
electric machine. Thus placed it is necessarily arranged in an insulating casing
and carried by an insulating support A'. This arrangement allows of the volume
of the whole of the apparatus being reduced.
M¹ M² are pole pieces of the magnets p between which rotates an armatures of
the Siemens type mounted on the shaft X on which a pulley y is mounted which
receives movement from the motor. The current induced in the armature is
rendered continuous in the usual manner by means of brushes B¹ B2 bearing on a
split ring commutator D, whilst nand o are two brush carriers which form the
terminals at the entrance and exit of the circuit. is a plate serving as support for
the brush carriers and o; o being in contact with this support, while n is
insulated by a ring n¹.
The way
in which the interrupter is formed which is directly combined with the
magneto electric machine actuated by its axis X and mounted in circuit between
the said magneto-machine and the induction coil, will now be described.
The end of the spring rod e of the hammer of the interrupter is mounted on a
little metallic spindle E engaged in a recess formed in the conducting base of the
magneto-machine and wound spirally. When the spring is of the desired tension,
the spindle E is fixed by means of a screw c, Figure 1 and the spring is held
externally by a milled disc d. The contact at the end of the rod e of the interrupter
is formed by a small piece of platinum y. In the support i of the brush carrier a
metallic arm h is fixed by means of an insulating ring j, which arm carries a
screw, the end of which forms the point against which the hammer g of the
interrupter bears and from which it will be separated for breaking the circuit,
according to the position of the cam m which forms the end of the spindle X (see
respectively Figures 3 and 4). At the point of contact between the cam m and the
rod e, we fix on this latter an ivory plate fin order to avoid the formation of
secondary currents. The position of the point may be regulated by means of a
nut l. On the arm there is fixed by means of a screw t, one of the ends 4 of the
primary wire of the Ruhmkorff coil, and also a wire u passing to one of the terminals
of the condenser. The other extremity 3 of the primary or inducing wire of the
coil is fixed directly to the brush carrier n, and finally a wire passing to the other
pole of the condenser is connected by screw to the base b. The two ends of the
fine or secondary wire J of the coil are attached to terminals R R¹ and wires from
lighting carbons or any other suitable apparatus serving to form the spark may be
connected with these terminals. The form and position of the cam m may be
regulated in relation to the collector, and the brushes may be keyed on this latter
so that the breakage of the circuit is produced an instant before the precise
moment when the current furnished by the magneto-machine or dynamo attains its
maximum intensity.
A simple examination of the figares shows that at each revolution of the shaft X
of the Siemens armature two breakages of the circuit will be produced and
consequently two sparks may be obtained.
As we have herein before indicated, instead of combining the interrupter with a
Siemeus armature, it may be placed in circuit between a dynamo or any suitable
magneto-machine and an induction coil. In cases for instance where a Gramme

page_text: ring is employed the interrupter may be operated by a cam having as many bosses
or projections as there are coils on the ring.
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. In electric sparking devices an arrangement enabling the production of the
spark by means of an induction coil to be regulated, characterised by an interruptor
being placed in circuit between an induction coil and the source of electricity
(dynamo or magneto-machine), said interrupter being actuated directly by a cam
mounted on the shaft of the dynamo or magneto-machine and forming one with the
said shaft, substantially as hereinbefore set forth.
2. In electric sparking devices the arrangement hereinbefore described and
shown in the accompanying drawings in which the interrupter is constituted by a
metallic spiral of adjustable tension connected with the base of the dynamo
machine.
7321
03
.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicants.