IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1878

page_text: LETTERS PATENT to Charles William Siemens, of No. 12, Queen Anne's Gate,
Westminster, in the County of Middlesex, for the Invention of "IMPROVEMENTS
IN ELECTRIC LAMPS." A cominunication from abroad by Hefner von Alteneck,
of Berlin. in the German Empire.
PROVISIONAL SPECIFICATION left by the said Charles William Siemens
at the Office of the Commissioners of Patents on the 4th December 1878.
"
CHARLES WILLIAM SIEMENS, of No. 12, Queen Anne's Gate, Westminster, in the
County of Middlesex. IMPROVEMENTS IN ELECTRIC LAMPS." [A communication
from abroad by Hefner von Alteneck, of Berlin, in the German Empire.]'
This Invention relates to the construction of electric lamps in such a manner
that the distance of the carbons between which the luminous arc is produced is
automatically adjusted, notwithstanding waste of the carbons themselves.
According to one arrangement for this purpose, the carbons are made in the form
of flat plates suspended from a framing above, so that they meet at an acute angle,
their flat sides being presented towards each other. One of these carbon plates
may be fixed, the other being attached to a lever pivotted on the framing above,
which lever is provided with an adjustable weight so as to press the edges of the
carbons towards each other with a moderate force, counteracting the repulsion pro-
duced by the existance of opposite electric currents in the two carbons.
The lever instead of being loaded as above described by a weight arranged nearly
in line with the carbon, may have the weight on an arm nearly at right angles to
the carbon, its opposite arm carrying an iron core which is free to move ир. and
down within a coil of insulated wire forming part of the electric circuit of the lamp.
When the carbon edges are close together a strong current passes, and this gives
the coil such an attracting power on the iron core, that it moves downwards
within the coil and separates the carbons. As they become separated, the current
is weakened, and less attraction is exerted on the iron core, which rising, allows

page_text: the carbons again to approach each other. The interior of the coil may be filled
with liquid or other known means of damping; the oscillations of the core may be
employed. By making the iron core small in diameter, or as a group of insulated
iron wires, the apparatus is rendered suitable for being worked by alternating
electric currents.
Instead of suspending the carbons with their meeting edges downwards as above
described, they may be filled in vertical slides in the usual way, the one above the
other, and in this case the adjusting apparatus is arranged in the following
manner: The iron core which is attracted downwards within the coil in opposition
to an adjustable weight or spring, or to the attraction of another iron core within a
coil of fine wire tending to draw it upwards, is connected by a lever with a vertically
sliding rod which is itself connected through a ratchet and pawl to the vertical
slide which carries the upper carbon. Within a limited amount of its stroke, this
rod and the carbon slide remaining connected, work up and down together in
accordance with the movements of the core within the coil, the strength of current
passing through the latter, thus serving to adjust the distance of the carbon points
within a certain range. But when the carbon is so far wasted that the rod and
slide descend to the lowest limit of the stroke, the pawl which connects them
becomes disengaged by coming against a fixed stop, and the carbon descends a
little farther, till the pawl becoming again engaged, the self adjusting movement is
resumed. The slide which carries the upper carbon may be connected through
suitable gearing or chains and pullies to the slide which carries the lower carbon, so
that when the former descends to allow for waste, the latter is at the same time
caused to ascend a less distance; the focal position of the light being thus main-
tained nearly constant. The descent of the carbon when its slide is disengaged
from the vertical rod, instead of being allowed to take place suddenly, is preferably
controlled by a pendulum movement worked by an escapement wheel geared to a
rack on the carbon slide. The movements of the core within the coil are also
damped by means of a piston working in an air cylinder or in any known manner.
According to a modified arrangement of this lamp while the feed of the carbons
as they are consumed is effected as above described, the adjustment of their distance
so as to meet variations in the electrical current is effected in the following
manner-The current on its way to the carbons is passed through a few coils, of
thick wire giving small resistance, and there is a shunt by which it can pass
through many coils of small wire offering considerable resistance without passing
through the carbons. The two sets of coils are arranged in line, and an iron rod
free to slide, as a core within them is connected by a lever to one of the carbons,
so that as the rod is attracted by the first mentioned coil the carbons are separated,
and as it is attracted by the second coil they are made to approach each other;
thus, supposing the carbons to be far apart so that no current can pass through
them, then the current must pass through the second coil, attracting the rod and so
making the carbons approach until the principal part of the current can pass
through them, and therefore through the first coil, causing an attraction of the rod
in the opposite direction, and so separating the carbons which are thus by the
counteraction of the two coils made to adjust themselves to suit the current, not-
withstanding considerable variations in its force, such as may arise from the
introduction of a number of lamps into one circuit. In this arrangement of lamp,
the feeding of the carbons as they waste is simply effected by disengaging the
carbon slide from the lever above mentioned at the extreme of its stroke in the one
direction, the carbon then descending by gravity or being caused to ascend by a
counterweight until the two carbons meet. When they do meet, the first coil is
brought vigorously into action, attracting the iron rod, and so causing the carbons
to separate till they adjust themselves as above described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles William Siemens in the Great Seal Patent Office on the
3rd June 1879.
CHARLES WILLIAM SIEMENS, of No. 12, Queen Anne's Gate, Westminster, in the
County of Middlesex. "IMPROVEMENTS IN ELECTRIC LAMPS." A communication
from abroad by Hefner von Alteneck, of Berlin, in the German Empire.
This Invention relates to the construction of electric lamps in such a manner that
the distance of the carbons between which the luminous are is produced is
automatically adjusted, notwithstanding waste of the carbons themselves.
According to one arrangement for this purpose the carbons are made in the form
of flat plates suspended from a framing above so that they meet at an acute angle,
their flat sides being presented towards each other. One of these carbon plates
may be fixed, the other being attached to a lever pivotted on the framing above,
which lever is provided with an adjustable weight so as to press the edges of the
carbons towards each other with a moderate force, counteracting the repulsion
produced by the existence of opposite electric currents in the two carbons. The
lever instead of being loaded as above described by a weight arranged nearly in
line with the carbon, may have the weight on an arm at right angles to the carbon,
its opposite arm carrying an iron core which is free to move up and down within a
coil of insulated wire forming part of the electric circuit of the lamp. When the
carbon edges are close together a strong current passes, and this gives the coil such
an attracting power on the iron core that it moves downwards within the coil and
separates the carbons. As they become separated the current is weakened and less
attraction is exerted on the iron core, which rising allows the carbons again to
approach each other. The interior of the coil may be filled with liquid, or other
known means of damping the oscillations of the core may be employed. By
making the iron core small in diameter or as a group of insulated iron wires, the
apparatus is rendered suitable for being worked by alternating electric currents.
Instead of suspending the carbons with their meeting edges downwards as above
described, they may be fitted in vertical slides in the usual way, the one above the
other, and in this case the adjusting apparatus is arranged in the following
manner The iron core which is attracted downwards within the coil in opposition
to an adjustable weight or spring, or to the attraction of another iron core within a
coil of fine wire tending to draw it upwards, is connected by a lever with a
vertically sliding rod, which is itself connected through a ratchet and pawl to the
vertical slide which carries the upper carbon. Within a limited amount of its stroke,
this rod and the carbon slide remaining connected work up and down together
in accordance with the movements of the core within the coil, the strength of
current passing through the latter thus serving to adjust the distance of the carbon
points within a certain range, but when the carbon is so far wasted that the rod
and slide descend to the lowest limit of the stroke, the pawl which connects them
becomes disengaged by coming against a fixed stop, and the carbon descends a little
farther till the pawl becoming again engaged, the self adjusting movement is
resumed. The slide which carries the upper carbon may be connected through
suitable gearing or chains and pulleys to the slide which carries the lower carbon,
so that when the former descends to allow for waste, the latter is at the same time
caused to ascend a less distance, the focal position of the light being thus main-
tained nearly constant. The descent of the carbon when its slide is disengaged
from the vertical rod, instead of being allowed to take place suddenly is preferably
controlled by a pendulum movement worked by an escapement wheel geared to a
rack on the carbon slide. The movements of the core within the coil are also
damped by means of a piston working in an air cylinder, or in any known
manner.

page_text: According to a modified arrangement of this lamp, while the feed of the carbons
as they are consumed is effected as above described, the adjustment of their distance
so as to meet variations in the electrical current is effected in the following
manner: The current on its way to the carbons is passed through a few coils of
thick wire giving small resistance, and there is a shunt by which it can pass
through many coils of small wire offering considerable resistance without passing
through the carbons. The two sets of coils are arranged in line, and an iron rod
free to slide as a core within them is connected by a lever to one of the carbons, so
that as the rod is attracted by the first mentioned coil the carbons are separated,
and as it is attracted by the second coil they are made to approach each other.
Thus, supposing the carbons be far apart so that no current can pass through them;
then the current must pass through the second coil, attracting the rod, and so
making the carbons approach until the principal part of the current can pass
through them, and therefore through the first coil, causing an attraction of the rod
in the opposite direction, and so separating the carbons which are thus by the
counteraction of the two coils made to adjust themselves to suit the current,
notwithstanding considerable variations in its force, such as may arise from the
introduction of a number of lamps into one circuit. In this arrangement of lamp
the feeding of the carbons as they waste is simply effected by disengaging the
carbon slide from the lever above mentioned at the extreme of its stroke in the one
direction, the carbon then descending by gravity, or being caused to ascend by a
counterweight until the two carbons meet. When they do meet the first coil is
brought vigorously into action attracting the iron rod, so causing the carbons to
separate till they adjust themselves, as above described.
DESCRIPTION OF THE DRAWINGS.
Fig. 1, Sheet I., shews the arrangement of electric lamp first mentioned above.
a, a¹, are the two carbons, which may be rods, round or square in section, but are.
preferably made in the form of flat plates, with their broad faces presented towards
cach other. The one carbon a is fixed, the other a¹ is attached to a lever lightly
pivotted on the framing, and having on it an adjustable counterweight b, which,
acting in opposition to the repulsive action of the opposite currents in the carbons
serves to maintain their lower edges at a suitable distance for producing the lumi-
nous arc. According to the modification shewn at Fig. 2, Sheet I., the lever b,
which carries the adjustable weight, has an arm from which is suspended an iron
core d, introduced into the middle of a coil c, which is in the circuit of the lamp,
and which, according to the greater or less strength of current passing through it,
attracts with greater or less force the core down into it, thereby separating more or
less the lower edges of the carbons a, a¹, and so serving for the automatic adjust-
ment of their distance. The cavity within the coil c is filled with a liquid to damp
the oscillations of the core d, which may be rendered very sensitive by making it
of thin iron or wire, so that the lamp can be worked by alternating currents. The
arrangement of lamp with an upper carbon sliding vertically is shewn at Fig. 1,
Sheet II., an enlarged view of the gear for connecting and disconnecting the carbon
slide being shewn at Fig. 2, Sheet 11. The upper carbon is attached to a rod S,
which is fitted to slide along a stem A supported on a lever g', and guided to move
parallel by a radius g. The lever g', which is pivotted to the framing at o', is linked
to an iron core E, supported by an adjustable spring f within a coil R, which is in
the lamp circuit.
A chain attached to the lower end of the slide S passes over a
wheel, having teeth to engage its successive links. The wheel is mounted on
the stem A, and is prevented from turning by a pawl z catching in the teeth of a
ratchet wheel on the axis of . So long as remains engaged with these teeth, the
slide S and the stem A remain firmly connected, both moving together in obedience
to the movements of the core E, which rises as the electrical force increases, and
Fig. 1, Sheet I., shews the arrangement of electric lamp first mentioned above.
a, a¹, are the two carbons, which may be rods, round or square in section, but are.
preferably made in the form of flat plates, with their broad faces presented towards
each other. The one carbon a is fixed, the other a¹ is attached to a lever lightly
pivotted on the framing, and having on it an adjustable counterweight b, which,
acting in opposition to the repulsive action of the opposite currents in the carbons
serves to maintain their lower edges at a suitable distance for producing the lumi-
nous arc. According to the modification shewn at Fig. 2, Sheet I., the lever b,
which carries the adjustable weight, has an arm from which is suspended an iron
core d, introduced into the middle of a coil c, which is in the circuit of the lamp,
and which, according to the greater or less strength of current passing through it,
attracts with greater or less force the core down into it, thereby separating more or
less the lower edges of the carbons a, a¹, and so serving for the automatic adjust-
ment of their distance. The cavity within the coil c is filled with a liquid to damp
the oscillations of the core d, which may be rendered very sensitive by making it
of thin iron or wire, so that the lamp can be worked by alternating currents. The
arrangement of lamp with an upper carbon sliding vertically is shewn at Fig. 1,
Sheet II., an enlarged view of the gear for connecting and disconnecting the carbon
slide being shewn at Fig. 2, Sheet 11. The upper carbon is attached to a rod S,
which is fitted to slide along a stem A supported on a lever g', and guided to move
parallel by a radius g. The lever g', which is pivotted to the framing at o', is linked
to an iron core E, supported by an adjustable spring ƒ within a coil R, which is in
the lamp circuit.
A chain attached to the lower end of the slide S passes over a
wheel, having teeth to engage its successive links. The wheel is mounted on
the stem A, and is prevented from turning by a pawl z catching in the teeth of a
ratchet wheel on the axis of r. So long as remains engaged with these teeth, the
slide S and the stem A remain firmly connected, both moving together in obedience
to the movements of the core E, which rises as the electrical force increases, and

page_text: descends as it diminishes. By these movements, as above explained, the distance
of the carbon points is automatically adjusted. When however the carbons become
so far consumed that the stem A has to descend to its lowest point, in order to
bring the carbon points sufficiently near for the passage of the electrical current,
then the pawl z, catching on a fixed projection v, is lifted out of gear with the teeth
of r, and the wheel being then free to revolve in the direction of the arrow, the
slide S with the upper carbon descends relatively to the stem A sufficiently far to
make up for the consumption of the carbons. To prevent the sudden descent of S,
another pawl y is provided to catch the teeth of , like the anchor of an escapement,
so that the wheel r can only turn intermittently one tooth at a time. The move-
ments of the core E are damped by a piston x working in an air cylinder. According
to a modified arrangement shewn in Fig. 3, Sheet II., the carbon slide S is toothed
at its edge as a rack engaging with a pinion on the axis of the wheel r, which
serves to connect it with the stem in the manner shewn in the enlarged view at
Fig. 4, Sheet II. The wheel has teeth working the escapement of a small pen-
dulum p. So long as the stem A is above its lowest position, this pendulum is
prevented from moving by its tail m being caught in the notch of a lever arm z,
which is pivotted on A. When however, owing to the consumption of the carbons,
the stem A has descended to its lowest position, then the arm z, catching on a fixed
stud v, is raised so as to clear the tail m out of the notch, leaving the pendulum
free to swing. The slide S then descends, causing the wheel r to turn in the direction
of the arrow, swinging the pendulum which controls its movement, and thus
continues till the stem A being again raised by the action of the core E under the
influence of an increased current, the pendulum tail m is again caught in the notch
of z, and the wheel is consequently stopped, thus arresting the descent of the
carbon slide. The wheel is provided with a pawl to prevent it from turning
backwards. The movements of the core E are in this case also damped by means
of a plunger K working in a cylinder. When it is desired to keep the luminous
arc in the same, or nearly the same focal position, the lower carbon, instead of being
stationary, has to be raised in proportion as it is consumed. An arrangement for
this purpose is shewn at Fig. 5, Sheet II. The stem of the socket T, which holds
the lower carbon, has at its lower end a pulley, round which is passed a chain; one.
end of the chain is fixed, and the other end is attached to the slide S, which carries
the upper carbon, so that as the upper carbon descends the lower one is caused to
ascend half the distance, which nearly corresponds with the rate of consumption of
the two carbons. The chain which connects the carbons is passed over a guide
pulley d and over the wheel r, which is mounted on a bracket projecting from the
regulating stem A. An arm has a pawl tooth engaging with ratchet teeth of r,
and preventing it from turning, except when on A descending to its lowest position
the arm z is raised by coming to bear on a fixed stud v, and the wheel + being thus
left free to turn, the upper carbon descends and the lower carbon ascends enough to
allow for their consumption.
Having thus described the nature of the said Invention and in what mauner the.
same is to be performed, as cominunicated to me by my foreign correspondent, I
claim,―
First. The arrangement in an electrical lamp of two carbon plates or rods pro-
jecting downwards, the one fixed and the other constituting the arm of a lever,
which is acted on by a counterweight or by a solenoid having its coil in the circuit
of the lamp in opposition to the repulsion of the opposite currents in the carbons
so as to adjust their converging edges to the distance suitable for producing the
luminous arc, substantially as herein described with reference to Figs. 1 and 2 on
Sheet I. of the accompanying Drawings.
Second. In an electrical lamp mounting one carbon on a slide so connected to a
regulating stem actuated automatically by the strength of the current that when
the said stem, owing to the consumption of the carbons, is made to attain the
extreme of its stroke, the carbon slide is left free to permit the approach of the

page_text: carbons, and when they have sufficiently approached, it is again connected to the
regulating stem, substantially as herein described.
Third. In electrical lamps operating in the manner referred to in the preceding
claim, effecting the connection of the carbon slide to the regulating stem, and its
disconnection therefrom by the action of a pawl or escapement on a ratchet wheel
mounted on the stem and driven by the slide, substantially as herein described with
reference to the Figures on Sheet II. of the accompanying Drawings.
In witness whereof, I, the said Charles William Siemens, have hereunto set
my hand and seal, this Thirtieth day of May, in the year of our Lord One
thousand eight hundred and seventy nine.
C. WILLIAM SIEMENS. (L.S.)