IMPROVEMENTS IN ELECTRIC LAMPS, AND IN THE MANUFACTURE OF THE ELECTRODES USED THEREIN
Year: 1877

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
ELECTRIC LAMPS, AND IN THE MANUFACTURE OF THE ELECTRODES USED
THEREIN." A communication from abroad by Emile Reynier, of Paris, France.
Sealed the 11th January 1878, and dated the 3rd August 1877.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 3rd August 1877.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN ELECTRIC LAMPS, AND IN THE MANUFACTURE
OF THE ELECTRODES USED THEREIN." [A communication from abroad by Emile
Reynier, of Paris, France.]
This Invention relates to improvements in electric lamps, the principal distinctive
features of which consist in rendering the progressive movements of the electrodes
or rheophores completely independent, 1st., the one of the other; and, of 2ndly, the
adjustment of the rheophores towards or away from each other and consequently of
their waste or consumption. This principle of independent progression of the
rheophores may or may not be combined with other processes, and under whatever
form it may be employed, such as the methods of establishing the light by sparks
of high tension, by interposing automatically or otherwise between the rheophores
and putting them in communication by a conducting body, by bringing the
rheophores into contact automatically, or otherwise, they being for this purpose
suitably jointed on their supports or by hand.
In this improved lamp the rotary rheophores are inclined at an angle (varying
from-20° to 120°) to each other, so as not to impede the formation of the voltaic arc.
This inclined arrangement of two rotating rheophores is novel, whether used in
combination or not with the system of independent progression above mentioned,
whatever may be the form, size, and general arrangement of the lamp.
The accompanying, Drawings show one arrangement of the lamp, in which the
bringing together and separating of the rheophores is automatically effected by the
combined opposing actions of springs and of a solenoid.

page_text: Figure 1 shows a front elevation of this arrangement of lamp; Figure 2, a side
view; Figure 3, a vertical section on line 1-2, Figure 1; and Figure 4, a horizontal
section on line 3-4, Figure 1.
The same letters of reference indicate the same parts in the several Figures.
a, base plate; b, b¹, pillars fixed in base a, and insulated therefrom by india-
rubber or ivory discs c. The pillars are forked at their upper part to carry the
rheophores and the mechanism for rotating them; d, d, circular rheophores pierced
at the centre to receive the clamps e, e¹, driven each by a train of clockwork f¹, f¹;
9, 9, trunnions, and g¹, g, coned screw centres, upon which the rheophores d, d,
and clock trains f, f¹, oscillate in the forks of pillars b, b1; h, forked lever, pivoted
at i on pillar b and connected to train f by a rod j; k, screw at the tail end of
lever h, resting on an insulated stud on base a; m, solenoid rising from base
plate a between the pillars b, b¹, and insulated from the base by a disc n; o, cylinder
of soft iron sliding in and almost in contact with the solenoid m, and connected by
rod p and connecting links 7, 8, to the clock train f¹ of rheophore d¹; t, t, spiral
springs attached at the upper end to the ends of a cross bar u, mounted in the
upper end of the rod p and at the lower ends to the lateral extensions v, v, of the
arms of a forked lever x, pivoted at on pillar b¹; g, screw in the tail end of
lever x, resting on an insulated stop 1 on base a; 2, 3, binding screws for attaching
the wires to the pillars b, b'.
The whole being arranged as described, the working of the lamp is as follows:-
The two clock trains f, fi, are first wound up, whereupon the two rheophores d, d¹,
begin to revolve independently of each other, the circuit is then completed, and
by turning the screw k the rheophore d is brought in contact with the other one d¹
to establish the light; the solenoid at same time becomes active, attracts and raises
the soft iron core, and separates the rheophores. The smaller the voltaic arc the
greater is the intensity of the current, and as the action of the solenoid overcomes
that of the springs t, t, the core o is drawn upwards and so separates the rheophores,
whereupon the voltaic arc is amplified, and the intensity of the current being
reduced the action of the solenoid is also diminished, and that of the springs t pre-
dominating, the rheophores are brought towards one another. In this manner
equilibrium is established between the opposing actions of the solenoid and springs,
and a steady uniform light is obtained.
The tension of the springs is regulated by screw z and lever x.
The apparatus may either be stood upright, as shown, or be suspended from a
bracket placed in a horizontal or other position.
Rheophores of the proper form and dimensions for this system of lamp cannot be
commercially produced from gas retort carbon, which, moreover, is not of uniforma
composition, and is liable to burst and crack, and form excrescences which displace
the light. All these defects, which are so objectionable in lamps using stick carbons,
are considerably aggravated in the case of circular rheophores.
The present Invention therefore includes the manufacture of rotary rheophores of
a composition of powdered graphite, 100 parts; powdered sugar, 20 parts; cast or
wrought-iron filings, 5 parts. The mixture is wetted with water acidulated with
from 1 to 5 per cent. of nitric or hydrochloric acid, so as to form a stiff paste. This
paste is then placed in the mould, shown in Figure 5, made of platinised or gilt
metal and there compressed more or less, according to the required density and rate
of combustion of the rheophores. The material is then dried either cold or at a
very gentle heat, and soon acquires sufficient consistency. It is then removed from
the mould and stoved for twenty-four hours at a temperature gradually rising
from 40° C. to 100° C., after which it is baked at a bright red heat for an hour
whilst protected from the air. The rheophore is then ready for use. It is however
preferable to coat it with nickel, copper, or brass, on one of its faces for the
purpose,-
1st. Of preventing the voltaic arc from reaching the interior of the acute angle.
2nd. Of minimising all useless lateral combustion.

page_text: And, 3rd. Of reflecting that portion of the light which is received on this face.
The best method of applying the metallic covering is by electro-deposition, or
the carbon may be moulded on a thin metal plate of the form shown in Figure 6,
and baked upon it so as to leave the metal plate permanently attached.
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
2nd February 1878.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN ELECTRIC LAMPS, AND IN THE MANUFACTURE
OF THE ELECTRODES USED THEREIN." A communication from abroad by Emile
Reynier, of Paris, France.
This Invention relates to improvements in electric lamps, the principal distinctive
features of which consist in rendering the progressive circular movements of the
rheophores completely independent the one of the other, and also of the adjustment
of the rheophores towards or from each other, and consequently of their waste or
consumption. This principle of independent progression of the rheophores may or
may not be combined with other processes, and under whatever form it may be
employed, such as the method of establishing the light by sparks of high tension,
by bringing the rheophores into contact automatically or otherwise, or by hand, &c.
The employment of circular rotating rheophores in electric lamps possesses the
great advantage of enabling apparatus of relatively small size to continue unin-
terruptedly in work for a long period, but on the other hand it gives rise to certain
difficulties; thus in the lamps having circular rheophores hitherto employed the
voltaic arc has either been partially obscured or fluctuating. And the improved lamp
forming the subject of the present Invention is designed to obviate these important
defects by rendering the voltaic are stationary and unobscured.
In order that the novelty and utility of the relative positions assigned to the two
circular rotary rheophores in this improved electric lamp may be more readily
understood, I will first of all describe, with reference to the Drawings, the arrange-
ments hitherto adopted, distinguishing the objections to each.
In Figure 1 the two circular rotating rheophores A, A¹, are situate in the same
plane, and their axes of rotation o, o¹, are parallel. The luminous point is partially
hidden and the voltaic arc fluctuates between c and d.
In Figure 2 the two circular rotating rheophores A, A', are in planes at right
angles to one another, the relative positions of the rheophores being such that the
plane of the one, if prolonged, would bisect the other rheophore diametrically; the
axes 0, 0¹, are also in different planes, and if projected on a plane perpendicular
to the plane of either rheophore, would intersect each other at right angles. With
such an arrangement the voltaic arc is nearly stationary, but the luminous point
is partly obscured and the discs cast considerable shadow. In the improved lamp
of this Invention, on the other hand, the rheophores are inclined to one another
at an angle of from 20° to 120°, as shown in Figure 3, their axes O, O¹, being
inclined to each other but in the same plane. The plane of one or other of the
two rheophores, if prolonged, would not intersect, or only slightly, the circumference

page_text: of the other rheophore. This novel arrangement of the rheophores does not impede
but rather aids the formation of the voltaic arc, and I therefore claim this inclined
arrangement of two rotating rheophores, whether used in combination or not with
the system of independent movements above referred to, whatever may be the form,
size, and general arrangement of the lamp.
The arrangement shown in Figure 4 is designed to more effectually expose and
localise the voltaic arc than in the arrangement, Figure 3, where the arc may
fluctuate between c and d. In order to thus localise the voltaic are the two circular
rheophores A, A', Figure 4, are in planes perpendicular to each other, the plane of
the rheophore A being nearly tangential to the circumference of rheophore A¹, so
that the plane of rheophore A¹, if prolonged, would bisect rheophore A diametrically,
while the plane of rheophore A, if prolonged, would not intersect, or would only just
intersect, the circumference of rheophore A¹. The axes of the rheophores are in
different planes, and if projected on a plane perpendicular to that of one of the
rheophores would intersect each other at right angles. This novel arrangement,
it will be seen, combines all the advantages of those shown in Figures 2 and 3,
localising as it does the voltaic arc, as in Figure 2, and leaving it unobscured, as
in Figure 3.
Figures 5, 6, 7, show the same relative arrangement of the rheophores as in
Figure 4, the luminous point being differently situated.
The Drawings further show, by way of example, one arrangement of the lamp in
which the approximation and the separation of the rheophores is automatically
effected by the combined opposing actions of springs and of a solenoid.
Figure 8 shows a front elevation of the lamp; Figure 9, a side view; Figure 10,
a vertical section on line 1-2, Figure 8; and Figure 11, a horizontal section on
line 3-4, Figure 8.
The same letters of reference are used in all the Figures to indicate the same
parts.
A, A¹, circular rheophores placed in the position indicated in Figure 4, that is to
say, the plane of one of the rheophores A is nearly tangential to the circumference
of the other rheophore A¹; a, base plate; b, b', pillars fixed on base a and insulated
therefrom by india-rubber or ivory discs c, the pillar b being forked at its upper
part to carry the rheophore A and the motor by which it is rotated; d, d', clock-
work motors for rotating the rheophores; e, e¹, axes of the rhcophores driven by
the motors d, d¹; f, trunnions; and g, g, coned screw centres, upon which the
rheophore A and clock train d oscillate in the fork of pillar b; h, plate at the top
of pillar b, having dovetail grooves in which the rheophore A¹ with its clock
train d¹ is fitted to slide, its position with regard to A, d, being regulated by an
adjusting screw . The plate h is insulated by interposing a non-conductor j
between it and pillar b'; %, solenoid rising from base plate a between the pillars b, bl,
and insulated from the base by a non-conductor ; m, cylindrical core of soft iron
sliding in and almost in contact with the solenoid , and connected by rod n and
link o to a forked arm p, embracing and fixed to the case of the clock train d of
rheophore A; , r, spiral springs attached at the upper ends to a cross head 8 on
rod n, and at the lower ends to the lateral extensions t, t, of the arms of a forked
lever u pivoted at v on pillar b¹; x, screw on the tail end of lever u, abutting
against an insulated stop y on base a, and serving to regulate the tension of the
springs;,, binding screws for attaching the conducting wires to the pillars b, b¹.
The whole being arranged as described, the working of the lamp is as follows:-
The two clock trains d, d, are first wound up, whereupon the two rheophores A, A¹,
begin to revolve independently of each other; the rheophore A¹ is then adjusted
in position by the screw i and the circuit completed, whereupon the action of the
solenoid attracts and raises the soft iron core m and separates the rheophore A
from A¹, thereby producing the voltaic arc. The smaller the voltaic are the greater
is the intensity of the current, and as the action of the solenoid overcomes the
opposing action of the springs t, r, r, the core m is drawn further upwards and
increases the distance between the rheophores; the voltaic are being thus amplified,

page_text: the intensity of the current is diminished, and the power of the solenoid lessened,
so that the power of the springs predominating, the rheophores are approximated.
In this manner equilibrium is established between the opposing actions of the
solenoid and springs, and a steady uniform light is obtained.
It will be understood that the lamp may either be stood upright, as shown, or
be suspended from a bracket, or placed in a horizontal or other position.
Rheophores of the proper form and dimensions for this lamp cannot be produced
commercially from gas retort carbon, which, moreover, is not of uniform composition,
and is liable to burst and crack and to forin excrescences which displace the light.
All these defects, which are so objectionable in lamps using stick carbons, are
considerably aggravated in the case of circular rheophores.
The present Invention therefore includes the manufacture of rotary rheophores
of a composition of powdered graphite, 100 parts; powdered sugar, 20 parts;
cast or wrought-iron filings, 5 parts; the mixture is moistened with sufficient water
acidulated with from 1 to 5 per cent. of nitric or hydrochloric acid to form a stiff
paste, which is then placed in the mould shown in Figure 12, made of platinised
or gilt metal, and compressed therein more or less according to the required
density and rate of combustion of the rheophores. The material is then dried
either cold or by a very gentle heat, and soon acquires sufficient consistency to
allow it to be removed from the mould. It is then stoved for 24 hours at a
temperature gradually rising from 40° C. to 100° C., after which it is maintained at
a bright red heat for an hour whilst protected from the air.
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. An electric lamp having circular rotary electrodes or rheophores, each
actuated by its own motor, so that the progressive rotary movements of the
rheophores are completely independent of one another and of the adjustment of the
rheophores relatively to each other, and consequently of the rate of their waste or
consumption, substantially as shown and described.
2nd. The application of the method of independent progression to any system
of electric lamp.
3rd. The combination with an electric lamp having rotary rheophores of a
solenoid acting on and effecting automatically the separation of the one from the
other, substantially as herein specified.
4th. The employment in electric lamps of two circular rotating rheophores
inclined at an angle to one another, the axes of the rheophores being in the same
plane as specified.
5th. The manufacture of the rheophores, as herein described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Second day of February, in the year of our Lord
One thousand eight hundred and seventy-eight.