IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1881

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 ELECTRIC LAMPS." A communication from abroad by Léonard Jules
Bouteilloux and William Laing, both of Paris, France.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 22nd July 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN ELECTRIC LAMPS." [A communi-
cation from abroad by Léonard Jules Bouteilloux and William Laing, both of
Paris, France.]
This Invention relates to electric lamps or regulators wherein the regulation of
the carbons is effected automatically by the action of gravity.
In order that the Invention may be more readily understood I have illustrated
in the accompanying Drawings several examples thereof, all embodying the principle
of automatic regulation.
In Figure 1 the apparatus consists mainly of two tubular carbon holders of
metal d, d, open throughout, and which may if necessary be provided at the lower
ends with tubular extensions of insulating material. The tubes are of such diameter
that the carbons g, g¹, may slide freely through them from one end to the other
when placed in a vertical or inclined position. The carbons rest at their lower
ends upon supports I, I¹. The carbons are inclined towards one another, and the
distance between their lower ends is adjusted by means of a screw M propor-
tionately to the power of the current produced by the generator. This done, and
the lamp having been put in communication with the generator, the incandescent
molecules are replaced as fast as they are consumed by those above, the carbons
being fed downwards in a gradual and continuous manner by their own gravity
without jerks, and without the aid of any mechanism or any intervening non-
conducting material. They will also, especially if of good quality, burn with great
regularity without changing their relative positions, and without any variation of
the distance apart at which they were originally set. Upon the lower part of the
.

page_text: :
carbon holders d, d', are placed sockets J, J', capable of sliding thereon, and held
in place by binding screws. These sockets carry the supporting arms I, I', made
of any suitable conducting or nonconducting material, and pivoted thereto at z to
permit of their adjustment. These supports are provided with recesses to receive
blocks H, H', of some refractory material, such as lime, magnesia, &c., upon which
the lower ends of the carbons directly rest.
Figures 2, 3, 4, 5, 6 show another arrangement of lamp of the saine kind, in
which the carbons are arranged in a particular manner. The upper carbon is a
solid stick of the ordinary kind, and rests by its own gravity upon the end of a
central nonconducting core contained within the lower carbon. The arc is thus
established between the point of the upper carbon and the circumference of the
conducting envelope of the lower carbon.
The regulation is effected automatically by the more or less rapid fusion of the
nonconducting core of the lower carbon, according to the intensity of the current,
but the interpolar interval can never be less than the radius of the central non-
conducting core.
Figure 2 is an elevation of the entire lamp; Figures 3 and are longitudinal
sections on a larger scale of the upper and lower carbon holders respectively; and
Figure 5 is a cross section on line 1-2, Figure 4; Figure 6 is a longitudinal
section on a still larger scale of the lower carbon, showing how the upper carbon
effects contact with the central core thereof.
The lamp frame represented in Figure 2 is of the lyre form generally used in gas
lighting. The frame consists of a top and bottoin part a, b, of metal or other
suitable material, united by arms c made of some non-conducting material; or the
arms e may be made of metal, and the parts a, b, of a non-conducting material; or
the entire frame may be made of metal, and the carbon holders alone be insulated.
The bottom part b is furnished with a split holder d for the lower carbon c screw
threaded externally to receive a nut f, by which it is firmly clamped upon the
carbon. The upper carbon is also fixed in a split holder h, also threaded
to receive a nut i, the said holder being free to slide through a socket k
on part a. The carbon thus rests by its own gravity upon the centre of
the core of the lower carbon, as shown in Figure 6. Any other suitable
method of fixing the carbons in their respective sockets may be employed. This
core becomes heated, and consumes at same rate as the carbon ; it remains
Juminous even after the interruption of the arc, and if the current continues it
fuses and volatilises, and the carbons approach each other until the arc is re-
established. The diameter of the carbons may-be-varied,-and-a number of then
may be grouped together in the same lamp. It will be seen that with the above
arrangement of the carbons the interpolar distance can never be reduced to zero, as
might happen if both had a non-conducting core, but must always be equal at least
to the radial distance between the upper carbon and the envelope of the lower
carbon. The lamp frame may be of any other form than that shown in Figure 2,
and if it be desired to enclose the light in a ground glass globe the carbon holders
may be mounted upon the globe itself, and be thereby insulated from one another.
These carbons may also be employed in existing lamps of all kiuds, and the light
may be directed where required by any kind of reflector.
All materials are here assumed to be non-conducting, which do not readily
transmit the current, but which notwithstanding contain a certain proportion of
conducting matter, conducting substances when so arranged as to prevent the
passage of the current being also considered as non-conducting. In certain cases,
for example, it would be of advantage to place a stick of carbon p in the centre of
the non-conducting core, as shown in Figure 7, which carbon being insulated does
not give passage to the current, the are being established as before between the
upper carbon and tubular envelope of carbon q, as shown in Figure 8. The
position of the carbons may be inverted, as shown in this latter Figure, a counter-
weight being employed for maintaining the lower carbon in contact with the
upper one; or any other equivalent acting by gravity may be adopted.

page_text: The carbons may also be otherwise arranged; Figure 9 shows an electric lamp in
which the position of the luminous focus is maintained constant by means of cords.
or chains & passing over guide pulleys t and attached to a single counterweight w.
The tubular carbon forming one of the electrodes filled with non-conducting
material, as herein before described, may be replaced by a number of sticks of
carbon surrounding the central non-conducting core. Figure 10 represents an
arrangement of regulator in which means are provided for obviating the defects
due to the changes which the nonconducting material undergoes under the
influence of the voltaic arc and the pressure of the solid carbon upon it. This
arrangement, which ensures the obtainment of a regular light and a perfect action
of the lamp, consists in the employment of a brake acting on the solid carbon in
such a way as to prevent pressing too forcibly against the nonconducting core, or -
as to hold it at a slight distance therefrom. The brake is pressed against the
carbon by a spring, the stress of which is at certain intervals overcome by an
electro magnet which may either be placed within the casing at the upper part, as
shown in Figure 10, or on the outside, according to the purpose or position of the
lamp. The electro magnet is placed either in the lamp circuit or in a derivation
thereof, according as the generator produces alternate or continuous currents.
In the example shown in Figure 10, A is the brake lever provided at one end
with an adjusting screw a carrying the brake shoe b, and at the other end with an
armature c; B is the electro magnet placed in a derivation of the circuit; C is the
solid carbon; D the tubular carbon having a non-conducting core; E is a spring
acting on the brake lever regulated by a screw F; G is the counterweight by
which the solid carbon is fed upwards, suspended from a chain attached to the
carbon holder and passing over a pulley on the cross piece L to whose other end
the brake lever A is pivoted; H is the tubular holder for the solid carbon; K is
the lamp st. adard; and S the support of the upper carbon D.
The current enters at the lower part of the lamp, passes up the standard K and
rod S to carbon D, forms the are and returns through the solid carbon. A. wire d
from support S is connected to one end of the coil of electro-magnet B, the other
end being connected with the solid carbon C the electro magnet is thus placed in
derivation. The brake b prevents the carbon C from rising too suddenly under
the action of the counter-weight G, but if it does not rise fast enough so that the
interval between C and D would become too great and so interrupt the arc, the
resistance of the principal current increases and the derived current becomes more
intense, whereupon the electromagnet overcoming the action of the spring
E attracts the armature C and draws back the brake from the carbon, thus
allowing the latter to rise and resume its normal position, after which, the current
through the electro-magnet becoming weaker the spring E withdraws the
armature c and the pressure of the brake upon the carbon is renewed. It might
happen sometimes that the brake retains the carbon until the interval becomes so
great that the arc would be extinguished, but this is obviated by utilizing for
effecting the automatic relighting the action of the electromagnet in derivation in
the way I will now describe with reference to Figure 11. To establish or
reestablish the arc automatically the lower carbon (which is of the ordinary solid
form) is so mounted as to be caused to deviate from the vertical when a powerful
current traverses the electro magnet placed in derivation.
The carbon on thus deviating from the vertical no longer bears upon the central
non-conducting core of the upper carbon, but upon its conducting envelope, and
the arc is thus instantaneously and automatically re-established. The intensity of
the current then diminishes in the electro-magnet and the lower carbon resumes
its vertical position.
In Figure 11, a is the upper carbon fixed by a binding screw b in its holder;
c is the lower carbon contained in a sheath and pressed up to the carbon a by a
piston e, chain f, and counterweight g; h, h, conducting wires; i, regulating
electro magnet; k, armature of magnet i, whose resistance is regulated by the
prolongation and spring m. The armature k is pivoted at n to the plate o. It

page_text: carries at its upper part the screw p for regulating the ascent of the lower carbon,
as before described, and also a bracket 7, upon which is mounted a screw r, which
when the armature is attracted presses against the carbon and causes it to deviate
sufficiently to effect, the relighting. The position of the mechanism represented in
full lines corresponds either to the period of rest, or to the norinal working of the
lamp. The dotted lines show the position for relighting.
It will be understood that the details of this automatic relighting arrangement
will vary in different cases, and that it may be applied to all systems of lamps in
which the carbons or conductors contain insulating material.
The regulating electro-magnet also may be replaced with advantage by a
galvanometric arrangement, whose action would be more regular than the electro-
magnet.
In order to check the upward movement of the lower carbon, which sometimes
becomes too abrupt in consequence of the electro-magnet acting slowly and the
armature remaining adhering to the electro-magnet, a clockwork operated by the
counterweight is placed inside the lamp to raise the carbon and maintain it at a
nearly constant distance.

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
21st January 1882.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN ELECTRIC LAMPS." A communi-
cation from abroad by Léonard Jules Bouteilloux and William Laing, both of Paris,
France.
This Invention relates to electric lamps wherein the regulation of the carbons is
effected automatically by the action of gravity.
In the accompanying Drawings, Figures 1, 2, 3, 4, 5, show a regulator of this
kind, in which the upper carbon is a solid stick of the ordinary kind resting by its
own gravity upon the end of a central nonconducting core contained within the
lower carbon (or the upper carbon may have the nonconducting core, and the lower
carbon be solid) so that the are is established between the point of the solid carbon
and the carbon envelope of the other carbon. The regulation is effected
automatically by the more or less rapid fusion or volatilization of the non-
conducting core according to the intensity of the current, but the interpolar
interval can or should never be less than the radius of the central nonconducting
core.
Figure 1 is an elevation of the entire lamp; Figures 2 and 3 are longitudinal
sections, on a larger scale of the upper and lower carbon holders respectively; and
Figure 4 is a cross section on line 1-2, Figure 3; Figure 5 is a longitudinal section
on a still larger scale of the lower carbon showing how the upper carbon rests on
the central core thereof, so that the reduction of the interval to zero and the
consequent extinction of the arc are prevented.
The lamp frame represented in Figure 1 is of the lyre form generally used in
gas lighting. The frame consists of a top and bottom part a, b, of metal or other
suitable material, united by arms c made of insulating material, or the arms c may
be made of metal and the parts a, b, of insulating material; or the entire frame
may be made of metal and the carbon holders alone be insulated. The bottom
part bis furnished with a split holder d, shown in Figure 4, for the lower carbon e
screwthreaded externally to receive a nut f, by which it is firmly clamped upon the
carbon. The upper carbon g is also fixed in a split holder threaded to receive a
nut i and free to slide through a socket / on part a, so that the carbon g rests by
its own gravity upon the centre of the core of the lower carbon, as shown in
Figure 5. Any other suitable method of fixing the carbons in their respective
sockets may be employed. Only one of the carbons has a nonconducting core l,
which becomes heated and is consumed at the same rate as the carbons; it remains
luminous even after the interruption of the arc, and if the current continues to pass
it fases and volatilizes, thereby allowing the carbons to approach each other until
the arc is re-established. The diameter of the carbons may be varied, and a
number of them may be grouped together in the same lamp. It will be seen that
with the above arrangement of carbons the interpolar interval can never be reduced
to zero, as might happen if both carbons had a nonconducting core, but must always
be equal at least to the radial distance m, n, Figure 5, between the solid carbon
and the envelope of the other carbon.
The lamp frame may be of any other form than that shown in Figure 1, and if
it be desired to enclose the light in a ground glass globe the carbon holders may
be mounted upon the globe itself and be thereby insulated from one another.
These carbons may also be employed in existing arc lamps of all kinds, and the
light may be directed where required by any kind of reflector.

page_text: All materials of which the core may be made are here assumed to be non
conducting if they do not readily transmit the current although they may contain
a certain proportion of conducting matter, and conducting substances are likewiso
so considered when arranged so as to prevent the passage of the current.
In
certain cases for example it would be of advantage to place a stick of carbon 2) in
the centre of the nonconducting core, as shown in Figure 6, which carbon being
insulated does not give passage to the current, the are being established as before
between the solid carbon g and tubular envelope of the carbon q, as shown in
Figure 7. In this Figure the position of the carbons is inverted and a counter-
weight is employed to maintain the lower carbon in contact with the upper one.
Any equivalent acting by gravity may be used instead of the weight.
The carbons may also be otherwise arranged. Figure 8 shows an electric lamp
in which the carbons are horizontal and the position of the arc is maintained
constant by means of cords or chains s passing over guide pulleys t and attached
to a counterweight u. The tubular carbon forming one of the electrodes filled
with nonconducting material, as hereinbefore described, may be replaced by a
number of sticks of carbon surrounding the central nonconducting core.
Figure 9 represents an arrangement of regulator in which means are provided
for obviating the defects due to the changes which the nonconducting material
undergoes under the influence of the voltaic arc and the pressure of the solid
carbon upon it. This arrangement which ensures the obtainment of a regular
light and a perfect action of the lamp consists in the employment of a brake held
by a spring against the solid carbon so as to prevent it pressing too forcibly
against the nonconducting core, or so as to hold it at a very small distance
therefrom. The action of the brake may be regulated by an electro magnet, which
may either be placed within the casing at the upper part, as shown in Figure 9, or
on the outside according to the purpose or position of the lamp. The electro
magnet is placed either in the lamp circuit or in a derivation thereof, according as
the generator produces alternate or continuous currents. In the example shown in
Figure 9, A is the brake lever provided at one end with an adjusting screw a
carrying the brake shoe b, and at the other end with an armature c; B is the
electro magnet placed in derivation; C is the solid carbon; D is the tubular carbon
having a nonconducting core; E is a spring acting on the brake lever regulated by
a screw F; G is the counterweight by which the solid carbon is fed upwards
suspended from a chain attached to the carbon holder and passing over a pulley on
the cross piece L to whose other end the brake lever A is pivoted; H is the tubular
holder_for_the-solid-carbon-;-K-is-the lamp standard, and S the support of the
upper carbon D. The current enters at the lower part of the lamp, passes up the
standard K and rod S to carbon D, forms the arc and returns through the solid
carbon. A wire d from support S is connected to one end of the coil of electro
magnet B, the other end 7 being connected with the solid carbon C; the electro
magnet is thus placed in derivation. The screw a and brake b prevent the carbon C
from rising too suddenly under the action of the counterweight G, but if it does
not rise fast enough so that the interval between C and D would become too great
and so interrupt the are, the resistance of the principal circuit increases and the
derived current becomes more intense, whereupon the electro magnet overcoming
the action of the spring E attracts the armature C and draws back the brake b
from the carbon, thus allowing the latter to rise and resume its normal position,
after which the current through the bobbin becoming weaker the spring E
withdraws the armature c and the pressure of the brake upon the carbon is
renewed.
It might happen sometimes that the brake retains the carbon until the interval
becomes so great that the arc would be extinguished, but this is obviated by
utilising, for effecting the automatic relighting, the action of the electro magnet in
derivation, in the way I will now describe with reference to Figure 10. To
establish or re-establish the are automatically, the lower carbon (which is of the
ordinary solid form) is so mounted as. to be caused to deviate from the vertical

page_text: when a powerful current traverses the electro-magnet; the carbon in thus deviating
from the vertical no longer coincides with the central nonconducting core of the upper
carbon, but comes opposite to its conducting envelope, and the arc is thus instan-
taneously and automatically established; the intensity of the current then
diminishes in the electro magnet, and the lower carbon resumes its vertical position.
The upper carbon might also be similarly inclined for the same purpose, or both
electrodes might be inclined simultaneously. The means of accomplishing this
will be understood by reference to Figure 10, in which a is the upper carbon fixed
by a binding screw bin its holder; c is the lower carbon contained in a sheath d
and pressed up to the carbon a by a piston e, chain f, and counterweight g;
1, h, conducting wires; i, regulating electro-magnet; k, armature of magnet i,
whose resistance is regulated by the prolongation and spring m. The armature k
is pivoted at n to the plate o; it carries at its upper part the screw p, forming the
brake for controlling the ascent of the lower carbon, as before described, and also a
bracket q, upon which is mounted a screw 7, which when the armature is attracted
presses against the carbon, and causes it to deviate sufficiently to effect the
relighting. The full lines in the Drawing represent the position of inaction, and
likewise the normal working position, and the dotted lines show the position for
relighting.
It will be understood that the details of this automatic relighting arrangement
will vary in different cases, and that it may be applied to all systems of lamps in
which the carbons or electrodes contain insulating material. The regulating electro
magnet also may be replaced with advantage either by a solenoid or by an apparatus
resembling a galvanometer, the oscillations of the needle being transmitted to one
of the electrodes by any suitable mechanical device; the action of such an apparatus
would be more regular than that of a solenoid or electro magnet.
In order to check the upward movement of the lower carbon which may some-
times be too abrupt in consequence of the electro magnet retaining the armature
against it, a train of wheels may be interposed to retard the counterweight and
raise the carbon, and maintain it at a nearly constant distance.
Figures 11, 12, 13, 14, and 15 represent another example of lamp upon the same
principle as the preceding, but provided with (1) two inclined carbons a, a, meeting
at their points, thus forming but a single A shaped electrode; (2), a second carbon
electrode b, Figure 13, of any suitable dimensions resting by its own weight, or pressed
by a spring c or counterweight upon a socket or annular stop d of refractory
insulating material fixed upon the end of a metal tube f through which the
electrode passes freely. The carbon is made tubular, and it may be hollow or
filled with a nonconducting core e. The upper electrode being lowered sufficiently
near to the angular electrode, the arc is established by means of a small piece of
conducting material introduced into the end of the hollow carbon b, as shown, or
the lighting and relighting may be effected by separating the two inclined carbons
a, a, forming the lower electrode, to permit of their rising up to the tubular carbon.
For this purpose an electro magnet is placed either in a derivation of the lamp
circuit or otherwise relatively to said circuit, and its armature j is fixed to one of
the inclined carbon holders so as to effect the separation of the angular electrode
and permit the two carbons a, a, to rise until they come in contact with electrode b.
The apparatus being suitably regulated the two carbons a, a, are brought together,
and the arc is then established. The two carbons a, a, are pressed together, and
are also fed up by the action of a weight sliding within the central tube i and
attached to two chains or cords le passing round a small pulley L, as shown, the
other ends of the cords being attached to small pistons sliding in the carbon holders
m, m, and pressing up the carbons a, a.
In the arrangement shown one pole is connected through the central tube i with
the two carbons a, a, and the other pole with the insulated support n of the upper
carbon b, electro magnet h being placed in a derivation of the lamp circuit by
means of wires p. 8 is a reflector which may be varied in form according to the
use to which the lamp is to be put. As the nature of the non-conducting material

page_text: modifies the color of the arc, I may avail myself of this means for obtaining lights
of any color desired, and of varying the color during the working of the lamp by
making the core slide freely through the tubular carbon, and introducing one which
will give the desired color to the light...
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 hereinbefore in part recited Letters Patent is, the improvements in electric
lamps, as herein shown and described, and consisting
1st. In the employment in combination of carbon electrodes, of which one has a
central core of insulating or insulated material for the other or others to bear
against for the production of the electric light, as described.
2nd. In a lamp in which one of the electrodes has an insulating core, as described,
the method of causing the other electrode or the clectrodes to deviate from the
normal working position, as and for the purpose specified.
3rd. The employment in combination with electrodes, constructed as herein
described, of a brake or train for preventing the too sudden motion of the electrode,
⚫as specified.
4th. The employment, either separately or combined, of the mechanism herein
specified with ordinary solid or hollow carbons.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty first day of January, A.D. 1882.