IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1879

page_text: LETTERS PATENT to Charles Dubos, of Paris (France), Electrician, for the
Invention of "IMPROVEMENTS IN ELECTRIC LAMPS."
PROVISIONAL SPECIFICATION left by the said Charles Dubos at the Office
of the Commissioners of Patents on the 3rd February 1879.
CHARLES DUBOS, of Paris (France), Electrician.
LAMPS."
IMPROVEMENTS IN ELECTRIC
For
My Invention relates to electric lamps in which the light is produced between
the ends of carbons at a little distance apart, and consists in making these carbons
in curved form and mounting and moving them in such manner as to keep the
luminous point in one focus, notwithstanding the consumption of the carbons.
this purpose I either bend to semicircular form the ordinary carbon rods while they
are in pasty condition before baking, or I mould carbon-rods in semicircular moulds
and bake them, obtaining in either way carbon-rods bent to semicircular shape.
I mount two of these in a lamp so that each presents its point towards the other,
the other end of each carbon being held in a socket at the end of a radius, so that
the two carbons when mounted together nearly complete a circle round a centre
about which the socket radii are free to move. On the axis of each radius are
fixed pullies, round which are passed cords or chains. One of these cords or chains
is in each case connected to a lever acted on by an adjustible weight or spring,
which by its effort to turn the radii tends to make the carbon points approach each
other. The cord or chain from the other pulley of each radius is connected to a soft
iron core, which is free to move within a coil of wire that forms part of the
electrical circuit of the lamp. The core being attracted into the coil acts on the
radii, so as to separate the points of the carbons. And thus by suitable adjustment
of the weight or spring to the attractive force on the core the distance of the carbon
points is automatically regulated, and continues to be so while the carbons them-
selves are consumed, the luminous point remaining. constant in its position.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
_by_the_said Charles Dubos in the Great Seal Patent Office on the 30th July
1879.
CHARLES DUBOS, of Paris (France), Electrician.
LAMPS
"IMPROVEMENTS IN ELECTRIC
My Invention relates to electric lamps in which the light is produced between
the ends of carbons at a little distance apart, and consists in making these carbons.
in curved form and mounting and moving them in such manner as to keep the
luminous point in one focus notwithstanding the consumption of the carbons. For
this purpose I either bend to semicircular form the ordinary carbon rods while they
are in pasty condition before baking, or I mould carbon rods in semi-circular moulds
and bake them, obtaining in either way carbon rods bent to semicircular shape.
I mount two of these in a lamp so that each presents its point towards the other,
the other end of cach carbon being held in a socket at the end of a radius, so that
the two carbons when mounted together nearly complete a circle round a centre
about which, the socket radii are free to move. On the axis of each radius are
fixed pulleys, round which are passed cords or chains. One of these cords or chains
is in each case connected to a lever acted on by an adjustible weight or spring,
which by its effort to turn the radii tends to make the carbon points approach each
other. The cord or chain from the other pulley of each radius is connected to a
soft iron core, which is free to move within a coil of wire that forms part of the
electrical circuit of the lamp. The core being attracted into the coil acts on the
radii so as to separate the points of the carbons. And thus by suitable adjustment
of the weight or spring to the attractive force on the core the distance of the carbon
points is automatically regulated, and continues to be so while the carbons them-
selves are consumed, the luminous point remaining constant in its position.
DESCRIPTION OF THE DRAWINGS.
Figs. 1 and 2 are vertical sections at right angles to one another, and Fig. 3 is a
part plan of one form of electric lamp, according to my Invention, suitable for being
suspended with the luminous are below. The two carbons C, C¹, of circular form,
are secured by setting screws a in sockets b at the end of radial arms c, c', which
are mounted free to turn on an axis o. To the arm c is attached a small pulley d
and a larger pulley D, and to c¹ in like manner are attached a pair of pullies d'
and D. Cords or chains E, E, are attached to the pullies D, D₁, and to an iron
core A, which is free to slide vertically within a solenoid coil S that is in the lamp
circuit. A cord or chain fattached to the top of the core A passes over the guide
pullies p, l, m, and n, and is attached to the end of a lever L, pivotted at k, and
having on it an adjustible weight P. The lever L, near its middle, has attached
to it a cord h which passes round a small pulley g. Attached to this pulley and on
the same axis is a larger pulley G, from which a cord or chain descends through a
groove in the core A and divides into two e, e¹, of which e is attached to the
pulley d and e¹ to the pulley d'. From this arrangement it will be seen that the
weight of the carbons and the arms supporting them, as well as the weight on the
lever L, tends to make the points of the carbons approach each other whilst the
attraction of the core A upwards into the solenoid coil when the electric current
passes through it tends to separate the points of the carbons. In obedience to
those two opposing forces the distance of the carbon points is automatically regu-
lated notwithstanding variations in the electric power, an increase of power giving
the solenoid more force to separate the carbons and a decrease of power giving it
less force. For the cords and pullies above described racks and pinions may
obviously be substituted. The light may be enclosed in an opal or other glass R
suspended from the upper part of the lamp. Fig. 4 is a front view; Fig. 5, a side
view; and Fig. 6, a plan of the underpart of a standard lamp according to my

page_text: Invention. In this arrangement the circular carbons C, C¹, are held in sockets b at
the ends of radial arms with counterweights p, p¹, that tend to make the points of
the carbons approach each other. One of the arms is fixed on an axis o, on which
is fixed a bevil pinion Q; the other arm is fixed on a sleever o¹, which has also on
it a bevil pinion Q. The two pinions Q, Q¹, engage with a bevil wheel P fixed on
an upright spindle D, having at its lower end two arms B, B¹, carrying iron cores
A, A', bent to a circular shape, so that they can move freely within solenoid coils
S, S', of circular form, which are in the circuit of the lamp. The two solenoids S, S¹,
when excited tend to draw the cores A, A', into them, causing the spindle D to
turn partly round and thereby through the gearing P, Q, Q¹, to move the carbon
points farther apart whilst the weights p, p, tend to bring them nearer together,
and thus the distance of the points suited to maintain the voltaic are between them
is automatically adjusted.
Having thus described the nature of my Invention, and in what manner the same
is to be performed, I claim,-
First. The use in electric lamps of carbons bent to circular shape and carried by
radial arms, whose movements round their axis are governed by solenoids having
their coils in the lamp circuit.
Second. The arrangement of suspended electric lamp having curved carbons,
herein described with reference to Figs. 1, 2, and 3 of the accompanying
Drawings.
Third. The arrangement of standard electric lamp having curved carbons, herein
described with reference to Figs. 4, 5, and 6.
In witness whereof, I, the said Charles Dubos, have hereunto set my hand and
seal, this Twenty second day of July, in the year of our Lord One thousand
eight hundred and seventy nine.
Witness,
JULES ARMENGAUD, jeune,
Of Paris,
Boulevard de Strasbourg, 23,
Civil Engineer.
CHARLES DUBOS. (LS.)