IMPROVEMENTS IN ELECTRIC LAMPS
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 ELECTRIC LAMPS." A communication from abroad by Jean Marie Anatole
Gérard-Lescuyer, of Paris, France.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 15th April 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN ELECTRIC LAMPS." [A communication from
abroad by Jean Marie Anatole Gérard-Lescuyer, of Paris, France.]
This Invention relates to an improved arrangement of electric lamp or burner,
which is distinguished from all others now in use by its simplicity, its great
lighting capacity in proportion to the expenditure of power, by the electrodes
being automatically maintained at an invariable distance apart, whereby absolute
fixity of the light is ensured, and also by the length of time during which it will
burn without attention.
The chief improvement consists in the arrangement of the electrodes, which are
each formed of two carbons inclined towards one another in the form of the
letter V, and so shaped at their points as to meet and touch one another in a
vertical plane passing through the axis of the apparatus. The two double electrodes
are automatically maintained at a suitable distance apart by mechanism hereafter
described, while the fixity of the arc is ensured by an electro-magnet arrangement.
In order that the Invention may be more readily understood I have illustrated
it in the accompanying Drawing, in which Figures 1 and 2 show respectively a
front and side view of the burner. The same letters refer to the same parts in
both Figures.
The burner is composed of two pairs of tubular carbon holders or guides
A, A, A, A, arranged in the form of an inverted pyramid, through which freely
slide the two electrodes, each formed of two carbons B, B, or B¹, B', bevelled off to
an acute angle at their lower ends so as to meet in a vertical plane, as shown in
Figure 2, whereby they mutually sustain each other, and are also free to descend
as fast as they are consumed. The whole of the burner mechanism is mounted on
C
•

page_text: the upper and under sides of a plate C, to one end of which the pair of tubular
holders A, A, are permanently attached, being insulated therefrom by a plate of
vulcanite E. The other pair of holders A¹, AT, are hinged at D to the opposite
end of plate C. A set screw F regulates the interval between the points of the
electrodes according to the tension of the current. The spring G is to maintain
this interval between the electrodes, the tension of the spring being regulated by a
screw H. I is an electro magnet placed in a derivation of the current through
conducting wires J, J; K is its armature attached to carbon holder A', A¹;
L, binding stud, to which one of the wires from the dynamo-electric machine is
attached, the other wire being connected to a second stud behind the first; M, M, are
rollers, which serve both to guide the carbons and to establish electric contact
between them and their holders in order that only a short length of the carbon
shall be included in the circuit; N is an electro-magnet through which the current
passes before entering the carbons in order to provent the formation of the voltaic
are at any other point between the electrodes; O is a hook by which the burner is
suspended.
The action is as follows:-The distance between the electrodes A, A, A', A', is
first regulated by screw F, and they are then connected with the two poles of the
machine. As communication is not yet established between the points of the
carbons the current passes through the electro magnet I, which by attracting its
armature K brings the electrodes in contact with one another. The current then
passes to the points of the carbons and ceases to flow through the electro magnet I,
which being demagnetised releases armature K and the spring G separates the
electrodes to the extent previously regulated by screw F, whereupon the voltaic
arc is established. Thus the electro-magnet I merely serves to establish the arc.
The carbons descend by their own gravity as fast as they are consumed in a
perfectly uniform manner, and the points maintain an invariable position.

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 14th
October 1880.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN ELECTRIC LAMPS." A communication from
abroad by Jean Marie Anatole Gérard-Lescuyer, of Paris, France.
This Invention relates to an improved arrangement of electric lamp or burner,
which is distinguished from all others now in use by its simplicity, by its great
lighting power in proportion to the small expenditure of motive power by the
electrodes being autimatically maintained at an invariable distance apart so as to
ensure absolute fixity of the light, and also by the length of time during which it
will burn without attention.
The chief improvement consists in the arrangement of the electrodes, which are
each formed of two carbons inclined towards one another, so as to form the lotter V,
and so shaped at their points as to meet in a plane passing through the axis of the
apparatus. The two double electrodes are also inclined towards one another, and
are automatically maintained at the proper distance apart at the points by mechanism
hereafter described, while the fixity of the arc is ensured by a fan shaped electro-
magnet.
In order that the Invention may be more readily understood I have illustrated it
in the accompanying Drawing, in which Figure 1 is a front elevation of the lamp
partly in section, one of the electro-magnets N being removed to show the parts
lying behind it; Figure 2 shows an elevation of the lower part only at right angles
to Figure 1. The same letters refer to the same parts in both Figures.
The lamp or burner is composed of two pairs of tubular carbon holders or guides
A, A, A, A¹, arranged in the form of an inverted pyramid, through which freely
slide the two electrodes respectively formed of two carbons B, B, and B', B', bevelled
off to an acute angle at their lower ends so as to meet in a vertical plane, as shown
in Figure 2, whereby they mutually sustain each other and are free to descend as
fast as they are consumed.
The whole of the mechanism is mounted on a plate C, to a flange at one end of
which the pair of tubular holders A, A, is permanently attached, a plate of vulcanite E
being interposed to insulate the holders from the plate. The other pair of holders
A', A', are hinged at D to the opposite end of plate C. By means of a set screw F
the interval between the points of the electrodes may be regulated according to the
tension of the current and the length of the arc it is desired to obtain, the said
interval being maintained by a spring G, the tension of which may be regulated as
required by a screw H. I is an electro-magnet placed in a derivation of the current
passing through conducting wires J, J, and K is its armature attached to the carbon
holders A', A; L, binding stud, to which one of the conducting wires from the
generating machine is attached, the other wire being connected to a second stud
behind the first; M, M, are gun metal rollers, which serve both to guide the carbons
and to establish electrical contact between the holders and the carbons near their
points, in order that only a short length of the carbon shall be included in the
circuit; N, N, is a fan shaped electro-magnet, through which the current passes
before entering the carbons, curved prolongations of the cores of the magnet being
arranged with regard to the carbons, as shown, in order to prevent the voltaic arc
rising between the electrodes. O, suspension hook.
The action is as follows:-The distance between the point of the double electrode
B, B, and that of the double electrode B', B', is first regulated by screw F, and the
binding screws L, L, are then connected with the two poles of the generating
machine. As communication is not yet established between the points of the
electrodes the current passes through and excites the electro-magnet I, which

page_text: attracts its armature K, and brings the points of the electrodes in contact with one
another.
The current then passes to the points of the carbons, and ceases to flow through
the electro-magnet I, which being demagnetised releases armature C, and the spring G
separates the electrodes to the extent previously regulated by screw F, whereupon
the voltaic arc is established; thus the electro-magnet I merely serves to permit
the establishment of the arc. The carbons descend by their own gravity as fast as
they are consumed in a perfectly uniform manner, and their points maintain an
invariable position.
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,-
1st. In an electric lamp the employment of an electrode or electrodes, each con-
sisting of two carbons inclined towards each other, and bevelled at the points so as
to meet, substantially as shown and described for the purpose specified.
2nd. In an electric lamp the combination of double carbon holder A, A, fixed to
plato C, with a similar but movable holder A', A¹, inclined towards the first, and
with means K, H, and G for regulating such inclination, substantially as shown and
described.
3rd. In an electric lamp the combination with the carbon holders and their
regulating mechanism, arranged and operating substantially as herein described, of
an electro-magnet I acting on an armature upon the movable carbon holder for
effecting the automatic establishment of the light, as described.
4th. In an electric lamp the employment of a fan shaped electro-magnet N
traversed by the current before it enters the carbons, the said electro-magnet being
arranged in relation to the carbons and acting to fix the arc, substantially as and
for the purpose specified.
5th. In an electric lamp the employment of rollers M for guiding the carbons and
establishing contact between them and their holders so as to reduce the length of
carbon included in the circuit, as specified.
6th. The general combination and arrangement of parts of the electric lamp,
constructed and operating in the mauner shown and described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Fourteenth day of October, in the year of our
Lord One thousand eight hundred and eighty.
A M
ATA TDK G