IMPROVEMENTS IN DIVIDING AND IN APPARATUS FOR REGULATING THE ELECTRIC LIGHT
Year: 1880

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of "IMPROVEMENTS
IN DIVIDING AND IN APPARATUS FOR REGULATING THE ELECTRIC LIGHT."
A communication from abroad by Louis Roguier, of Paris, France.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 7th January 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN DIVIDING AND IN APPARATUS FOR REGULATING
THE ELECTRIC LIGHT." [A communication from abroad by Louis Roguier, of
Paris, France.]
"
The object of this Invention is to remedy the defects to which the "Lontin
and similar systems are liable, by placing the apparatus to be operated by the
current in the principal circuit (as in regulators working on independent circuits)
and in derivation, a resistance formed of a stick of plumbago, a platinum wire, or
even a column of liquid, but preferably a carbon of small diameter and high
resistance, forming a sort of auxiliary circuit.
Figure 1 of the accompanying Drawings illustrates the theory of this arrange-
ment. The current, as will be seen, is divided through two branches, in one of
which is the electro magnet or solenoid regulator, and the arc or other source of
light; and in the other the resistance, the branches being reunited at the other
side thereof, and passing on as a single wire to the next lamp. By this arrange-
ment the defects of the derivation are obviated, viz. :-(1.) The coil may be of
thick wire, and therefore will not be sensibly heated by the passage of the current,
and its insulating covering will not be destroyed. (2.) Want of constancy in the
action of the coil is avoided, because being placed on the principal circuit it is
subject to all the variations of the current. (3.) The irregular heating is avoided,
the resistance consisting generally of insulated carbon sticks which readily part
with their heat and quickly return to their initial temperature. (4.) As it is not
necessary to make a resistance of the coil, it is constructed with a view solely to
the purpose of regulation.
Besides this mode of division, which is applicable to all known kinds of regu-
lators, the Invention also relates to a mechanical arrangement for maintaining the

page_text: length of the arc constant. In ordinary regulators the mechanism by which the
carbons are fed up and the motive mechanism are one and the same; even in the
Serrin lamp the weight of the carbons is the motive power, the electro magnet or
solenoid serving only to throw these mechanisms into and out of gear; hence
there is a sudden starting and stoppage which impairs the fixity of the light.
In the system of this Invention the mechanism for feeding up the carbons is
quite independent of the motive mechanism, and it is only progressively and
proportionately to the power of the electro magnet or solenoid that the one
actuates the other.
Figure 2 shows an example in which the motive mechanism is represented by
two barrels D, D¹, in opposite directions, and that for feeding up the carbons by a
right and left handed feed screw G, G¹, or instead of a screw a train of wheels
might be used. The two mechanisms are connected by a friction coupling consisting
of discs A, A¹, having indiarubber rims, which being pressed by the action of the
solenoid I up against dises B, B¹, on the ends of the screws G, G', rotate the latter
(with a greater or less amount of slip) in the one direction or other, according to
the barrel which is brought into action.
To avoid unwinding the barrels uselessly the friction discs press against fixed
plates C, C, when the apparatus is not working. The reference letters in Figure 2
indicate the following parts:
(I.) The Motive Mechanism.-This consists of the coupling discs A, A¹, with
indiarubber rims, plates C, C¹, barrel D turning to the left, barrel D' turning to
the right, and the connection at E¹ with the forked end of a lever actuated by the
solenoid.
(II.) The Mechanism for Feeding Up the Carbons.-This consists of the left
and right handed screws G, G, the discs B, B¹, fixed thereon, the insulating
coupling H, and the carbon holders F, F', provided with nuts working on the
screws G, G¹.
(III.) The parts acted on by the current consist of the solenoid I and its core J;
K, K', are levers pivoted at L, L¹, and M is a rod connected thereto and to the
core of the solenoid.
IV. The Resistance, Consisting of a Stick of Carbon.-Instead of the above
mechanism for regulating the lamp an electric brake formed of a series of soft iron
plates turning opposite a system of electro-magnets suitably arranged may be
employed to moderate the movement. This brake operates with a power increasing
with the tension of the current.
In Figure 3 I have illustrated a modification in which the electro-magnet a of
the burner is placed in a derivation, and the derivation is regulated automatically
by means of an apparatus consisting of a solenoid 6 placed in the main circuit, and
provided with a cylindrical iron core c attached by a rod to a metallic crosshead
that connects the upper ends of two rods fof carbon, which terminate at the lower
ends in winged pistous d, which are immersed in mercury contained in glass
tubes e.
g

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the 7th
July 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
" IMPROVEMENTS IN DIVIDING AND IN APPARATUS FOR REGULATING
THE ELECTRIC LIGHT." A communication from abroad by Louis Roguier, of Paris,
France.
The division of the electric light, when the arc is employed, has hitherto been
obtained only by maintaining the carbons at a constant, or nearly constant, distance
apart. This may be done in two ways:-(a.) By arranging the carbons parallel
with one another, as in the Jablockoff "candle." (b.) By placing the magnetic
apparatus, which regulates the advance or retraction of the carbons, either wholly
or partly in a derivation of the principal current, as in the Lontin system.
The present Invention relates not only to mechanical arrangements for regulating
the length of the arc, but also to a new mode of division.
The defects of the Lontin and similar systems are:-(1.) The electro-magnet or
solenoid placed in derivation must necessarily have a high resistance, and it
therefore soon becomes heated, which deteriorates the insulating material, and may
completely destroy it in a very short time. (2.) As the derivation must have a
much higher resistance than the arc it is traversed by a very small fraction of the
current, and is consequently not so sensitive as if it were placed in the principal
circuit, as it in fact only acts in limited cases. (3.) As the resistance of a conductor
is greatly modified by heat, the coil, of which the rise and fall of temperature due
to its specific heat is far from following the variations of the derived current, being
no longer regulated after a short time by the temperature at which it happens to
be, irregularities in the working of the apparatus ensue. (4.) Owing to the number
of spirals required to obtain the desired resistance it is necessary to employ a
number of coils, which complicates the apparatus.
The object of this Invention is to remedy these defects by placing in the principal
circuit the part of the apparatus to be influenced by the current (as in regulators
working on independent circuits) and in derivation, a resistance formed of a stick of
plumbago, a platinum wire, or even a column of liquid, but preferably a carbon of
small diameter and high resistance, forming a sort of auxiliary circuit.
Figure 1 of the accompanying Drawings illustrates the theory of this arrange-
ment. The current, as will be seen, is divided through two branches, in one of
which is the electro-magnet or solenoid regulator, and the arc or other source of
light, and in the other the resistance, the branches being reunited at the other side
to a single wire passing on to the next lamp. By this arrangement the defects of
the derivation are obviated, that is to say:-(1.) The insulating covering of the
coil will not be destroyed, as the coil may be of thick wire, and therefore will not
be sensibly heated by the passage of the current. (2.) Inconstant action of the
coil is avoided because, being placed on the principal circuit, it is subject to all the
variations of the current. (3.) Irregular heating is avoided, the resistance
consisting generally of insulated carbon sticks which readily part with their heat
and quickly return to their initial temperature. (4.) As it is not necessary to
make a resistance of the coil it is constructed with a view solely to the purpose of
regulation.
Besides this mode of division, which is applicable to all known kinds of regulators,
the Invention also relates to a mechanical arrangement for maintaining the length
of the arc constant. In ordinary regulators the mechanism by which the carbons
are fed up and the motive mechanism are one and the same; even in the Serrin
lamp the weight of the carbons is the motive power, the electro-magnet or solenoid

page_text: serving only to throw these mechanisms into and out of gear; hence there is a
sudden starting and stoppage which impairs the fixity of the light.
In the system of this Invention the mechanism for feeding up the carbons is
quite independent of the motive mechanism, and it is only progressively and
proportionately to the power of the electro-magnet or solenoid that the one actuates
the other.
Figure 2 shows an example in which the motive mechanism is represented by
two spring barrels D, D', turning in opposite directions, and that for feeding up
the carbons by a right and left handed feed screw G, G¹. In other arrangements a
train of wheels might be used instead of a screw. The two mechanisms are
connected by a friction coupling consisting of discs A, A', having india rubber rims
which, being pressed by the action of the solenoid I up against discs B, B', on the
ends of the screws G, G¹, rotate the latter (with a greater or less amount of slip) iu
the one direction or other, according to the barrel which is brought into action.
To avoid unwinding the barrels uselessly the friction discs press against fixed
plates C, C, when the apparatus is not working. The reference letters in Figure 2
indicate the following parts:-
(I.) The Motive Mechanism.-This consists of the coupling discs A, A¹, with
india rubber rims, spring barrel D turning to the left, spring barrel D¹ turning to
the right, and the connection at E' with the forked end of a lever actuated by the
solenoid.
(II.) The Mechanism for Feeding Up the Carbons.-This consists of the left and
right handed screws G, G, the discs B, B', fixed thereon, the insulating coupling H,
and the carbon holders F, F', provided with nuts working on the screws G, G.
(III.) The parts acted on by the current consist of the solenoid I and its cord J
which is connected by a rod M to levers K, K', pivoted at L, L'.
IV. The Resistance, Consisting of a Stick of Carbon N.-Instead of the above
mechanism for regulating the lamp an electric brake formed of a series of soft iron
plates turning opposite a system of electro-magnets suitably arranged may be
employed to moderate the movement. This brake operates with a power increasing
with the tension of the current.
In Figure 3 I have illustrated a modification in which the electro-magnet a of
the burner is placed in a derivation, and the derivation is regulated automatically
by means of an apparatus consisting of a solenoid 6 placed in the main circuit, and
provided with a cylindrical iron core c attached by a rod h to a metallic crossbead g
that connects the upper ends of two rods f of carbon, which terminate at the lower
ends in winged pistons d which are immersed in mercury contained in glass
tubes e.
In the foregoing arrangements the lamps are rendered independent by means of
the derivation, but this independence is detrimental to the intensity of the other
lights in the circuit. This objection is avoided by the modification represented in
Figure 4; this consists in placing in the direct circuit an electro-magnet for ench
lamp. When the light is established the electro-magnet attracts an armature, but
should it be extinguished the whole current passes through the derivation as
before described, and the armature of the electro-magnet being no longer attracted
falls by gravity and closes the circuit metallically, whereupon nearly the whole of
the current passes through this metallic circuit instead of the derivation. Figure 4
shows an example of such an arrangement in which three candles A, B, B¹, are
placed in the same circuit. C, battery; D, electro-magnet in principal circuit;
E, derived circuit; F, armature mounted on lever G, G¹; H, copper plate with
which the lower end G¹ of lever is brought in contact by the weight of the
armature when the electro-magnet is inert. Should light A become extinguished
the circuit E, A, I, D, J, and is broken, the current still passing to the other
candles through the circuit ε, E, 0. The armature then oscillates lever G, G¹, and
the current leaving the auxiliary circuit ε, E, e, which has the higher resistance,
passes almost wholly through the circuit &, K, G, G, H, O. The other lights then
receive the current direct and increase in intensity. If it be desired to always

page_text: maintain the same intensity it is only necessary to introduce into circuit E, K,
G, G, H, e, a resistance equal to the candle extinguished. In any case it is
indispensable to place in this circuit a resistance rather greater than that of the
self acting switch of the Jablochkoff candle to enable another candle to be lighted
in place of the one accidentally extinguished.
+
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is,-
1st. In an electric lamp, the combination of two distinct mechanisms, a motor
and feed mechanism for the carbons, said mechanisms being geared together either
proportionately to the power of an electro-magnet placed in the principal circuit or
under the control of electric brakes, substantially as and for the purpose herein
before described, and represented in Figures 1 and 2 of the Drawings.
2nd. An apparatus in which the division of the electric light is obtained by a
derivation having no direct action on the mechanism of the lamp itself, but which
together with the parts of the lamp offers a constant resistance to the current, as
described with reference to Figure 3.
3rd. An apparatus in which the division of the electric light is obtained without
the intensity of the other lights in the circuit being affected by the extinction of
one of them by the employment with each lamp of an electro-magnet placed in the
direct circuit, a derivation, and an oscillating armature, all arranged and operating
as described with reference to Figure 4.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Seventh day of July, in the year of our Lord One
thousand eight hundred and eighty.
A. M. CLARK. (L.S.)