IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1882

page_text: LETTERS PATENT to William Robert Lake of the firm of Haseltine Lake
& Co, Patent Agents, Southampton Buildings London for an invention of
"IMPROVEMENTS IN ELECTRIC LAMPS Communicated to him from abroad
by Franz Krizik and Ludwig Piette, both of Pilsen, in the Empire of Austria
"
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents on the 9th June 1882.
WILLIAM ROBERT LAKE, of the firm of Haseltine Lake & Co, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN ELECTRIC LAMPS [A
communication to him from abroad by Franz Krizik and Ludwig Piette, both
of Pilsen, in the Empire of Austria]
This invention relates to electric lamps and is designed to provide improved
means for effecting automatically the regulation of the distance apart of the carbon
rods or conductors, without the aid of clock work or other like mechanism, by the
use of a solenoid or solenoids having a core made as hereinafter described.
According to this invention I arrange, in an electric lamp, a solenoid-coil with
an iron core of a tapering shape and free to slide lengthwise within the coil; this
core carrying at its thickest end one of the carbons of the lamp. The iron core
being of a tapering shape and its lower thickest end being connected with one of
the carbons, whilst the upper pointed end passes through the solenoid-coil, a greater
attraction will be exerted on the lower thicker part than on the upper thinner part
of the tapering iron core when a current passes through the solenoid coil, and the
core will therefore then be drawn upwards through the solenoid coil.
The said tapering iron core carrying the upper carbon is connected by cords and
pulleys with a frame carrying the lower carbon, and the two arrangements are so
balanced that as long as no current passes through the lamp the weight of the iron
core with the upper carbon will overcome the weight of the frame with the lower
carbon and the carbon points will then touch each other.

page_text: When, however, a current passes through the lamp it flows also through the
solenoid-coil and will cause the said coil to exert a force having the tendency to
draw up the tapering iron core and so separate the carbons. But this can take
place only when the attractive force of the solenoid-coil is sufficient to overcome
the weight of the iron core balancing the lower frame. When this is the case the
iron core will be drawn up until the weakening of the current caused by the
formation of the voltaic are between the carbons, is such that the attraction and
the weight balance each other. When the current becomes still weaker by the
consumption of the carbons increasing the distance between them, the weight of
the iron-core will overcome the attraction of the solenoid coil and the core will
sink so as to bring the carbons nearer together. In this manner the two forces
constantly balance each other and keep the carbons the proper distance apart. In
order to increase the delicacy of the relative adjustment of the carbons the main
solenoid coil is covered by a second coil of a high resistance, and it has been found
advantageous to give the inner coil a diameter increasing step by step upwards
whilst the diameter of the outer coil decreases step by step upwards.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the
7th December 1882.
"
A
WILLIAM ROBERT LAKE of the firm of Haseltine, Lake & Co Patent Agents,
Southampton, Buildings, London " IMPROVEMENTS IN
ELECTRIC LAMPS
communication to me from abroad by Franz Krizik and Ludwig Piette both of
Pilsen in the Empire of Austria
This invention relates to electric lamps and is designed to provide improved
means for effecting automatically the regulation of the distance apart of the carbon
rods or conductors, without the aid of clockwork or other like mechanism, by the
use of a solenoid or solenoids having a core made as hereinafter described.
According to this invention I arrange in an electric lamp, a solenoid-coil with
an iron core of a tapering shape, and free to slide lengthwise within the coil;
this core carrying at its thickest end one of the carbons of the lamp. The iron
core being of a tapering shape, and its lower thickest end being connected with one
of the carbons, whilst the upper pointed end passes through the solenoid coil a
greater attraction will be exerted on the lower thicker part than on the upper thinner
part of the tapering iron core when a current passes through the solenoid coil, and
the core will therefore then be drawn upwards through the solenoid coil.
The said tapering iron core carrying the upper carbon is connected by cords and
pulleys with a frame carrying the lower carbon, and the two arrangements are so
balanced that as long as no current passes through the lamp the weight of the
iron core with the upper carbon will overcome the weight of the frame with the
lower carbon, and the carbon points will then touch each other.
When however, a current passes through the lamp it flows also through the
solenoid-coil and will cause the said coil to exert a force having the tendency to
draw up the tapering iron core, and so separate the carbons But this can take
place only when the attractive force of the solenoid is sufficient to overcome the
weight of the iron core balancing the lower frame. When this is the case the iron
core will be drawn up until the weakening of the current caused by the formation
of the voltaic are between the carbons, is such that the attraction and the weight
balance each other. When the current becomes still weaker by the consumption
of the carbons increasing the distance between them, the weight of the iron core
will overcome the attraction of the solenoid coil and the core will sink so as to
bring the carbons nearer together. In this manner the two forces constantly
balance each other and keep the carbons the proper distance apart
In order to increase the delicacy of the adjusting solenoid its coil is wound step
by step to a larger diameter upwards and in the spaces given by these steps is
wound an opposite coil of high resistance, connected in a shunt or by-pass to the
lamp circuit, this latter coil having the effect of weakening the former coil.
Fig: 1 of the accompanying drawings is a side view of a lamp according to this
invention, and fig: 2 is a transverse section. A frame A B C D, carrying the
lower carbon K¹ is guided by rollers ¹¹, and suspended by non-conducting cords
which pass over pullies R R and are attached to the lower part of a brass tube S.
This tube is guided by rollers r r, it carries the upper carbon K and has within
it the taper iron core C. The coil of large wire Z is wound by steps as shewn in
Fig 2 and the coil of fine wire Y is oppositely wound in the spaces of the steps.
When the lamp is in action the current entering at the positive post passes by the
rollers to the tube S, thence through the upper carbon K, the voltaic arc, the
lower carbon K', the frame A. B. C. D., the rollers ¹¹ and their supports m m to
the stationary framing of the lamp then through the coil Z to the negative post
:

page_text: The upper carbon K is maintained at the required distance from the lower
carbon K by the attraction of the solenoid coil Z on the taper core C and by the
weight of the frame A B C D and lower carbon, drawing it upwards in opposition
to the weight of the core C and tube S acting downwards. When the distance
of the carbons and consequently the resistance of the arc is too small the larger
quantity of current passing through the coil Z increases its attractive power
causing the carbon K to ascend. When the distance of the carbons and conse-
quently the resistance of the arc is too great the attractive power of the coil Z is
diminished, not only by the reduction of the current passing through it, but also
by the weakening influence of the opposite coil Y which being in a by-pass receives
an increased amount of current, and the carbon K descends. Owing to the tapering
shape of the core C the action above described remains practically uniform
notwithstanding its varying position as the carbons are consumed.
Having thus described the nature of the said Invention and in what manner the
same is to be performed as communicated to me by my foreign correspondents,
I claim :-
First-The herein described method of regulating the arc of an electric Lamp
by the attractive influence of a solenoid coil on a tapering iron core attached at
its large end to the holder of one of the carbons of the lamp, and partly balanced
by the other carbon and its holder.
Second-The construction of electric arc lamp with regulating solenoid and
tapering core, substantially as herein described:
In Witness whereof, I the said, William Robert Lake, have hereunto set my
hand and seal this Sixth day of December in the year of Our Lord, One
thousand, Eight hundred and Eighty-two