IMPROVE- MENTS IN OR RELATING TO ELECTRIC LIGHTS
Year: 1882

page_text: "
LETTERS PATENT to Thomas John Handford of 42 Southampton Buildings
in the County of Middlesex Patent Agent. for an invention of IMPROVE-
MENTS IN OR RELATING TO ELECTRIC LIGHTS A communication from abroad
by Thomas Alva Edison of Menlo Park in the State of New Jersey, United
States of America.
"3
PROVISIONAL SPECIFICATION left by the said Thomas John Handford at
the Office of the Commissioners of Patents on the 2nd May 1882.
"
THOMAS JOHN HANDFORD of 42 Sonthampton Buildings in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN OR RELATING TO ELECTRIC LIGHTS
a communication from abroad by Thomas Alva Edison of Menlo Park in the State
of New Jersey United States of America.
This Invention has for its object the production of simple and efficient forms and
arrangements of arc-lights,, and especially of simple and efficient regulating
mechanism for the same.
According to one part of the invention two electro-mgnets or solenoids of the
same or approximately the same resistance are employed to regulate the feed of
the upper or positive carbon electrode. One of these electro-magnets or solenoids
is located in a shunt around the arc, while the other electro-magnet or solenoid is
placed in series with such are and the carbon electrodes. The second electro magnet
or solenoid while being of the same electrical resistance as the first, has a greater
weight of copper in its coils and consequently has a predominating strength when
the carbon electrodes are touching. A shunt circuit having a low resistance, is
formed around this second electro-magnet or solenoid, so as to properly supply the
light. The two electro-magnets or solenoids act upon the upper or positive carbon
through any known or suitable mechanism. A gripping eye or collar may be used,
or other form of device, the arinature or core working the same being acted on
oppositely by the two electro-magnets or solenoids. The heavier electro magnet or
solenoid serves to lift the carbon electrode and to form the arc, while the lighter
electro-magnet or solenoid counteracts the effect of the heavier one when the arc
becomes too great and allows the upper electrode to drop to the proper point. In
this way a continuous feed is produced.
Or a permanent steel magnet may be used in place of the electro-magnet in the
line, so as to oppose in its action an electro-magnet located in a shunt circuit
around the arc. One end of the permanent magnet is connected directly with one
end of the soft iron core of the electro-magnet The armature at the other end of
the core works or controls the gripping eye or other device or mechanism which

page_text: regulates the feed of the upper carbon electrode. When the carbons are together
the permanent magnet predominates and the upper carbon is lifted to form the arc.
As the arc becomes larger the electro-magnet receives more current and becomes
stronger. It finally overcomes the sustaining effect of the permanent magnet and
allows the carbon to drop to the proper point.
Or one of the opposing elements of the regulating mechanism may consist of a
heating coil enclosed in a chamber having an expansible end. This heating coil is
located in a shunt around the arc, and opposes in its action an electro magnet or
solenoid in the main line. The armature of the electro-magnet, or its lever, or the
core of the solenoid may be attached directly to the expansible end of the chamber.
When the carbon electrodes are together, the electro magnet predominates and lifts
the upper carbon, forming the arc. As the arc increases, more current is shunted
through the heating coil, and the air in the chamber is raised in temperature and
exerts a greater pressure on the expansible end This pressure finally predominates
over the power of the electro-magnet, and the carbon electrode drops to the proper
point.
According to another part of the invention, a simple and efficient manner of
arranging and connecting voltaic arc lights is produced, whereby the lamps will be
wholly independent of each other, and can be repaired, or replaced individually
without affecting the other lamps of the system, that may be in operation, and
without the use of cut-out devices to preserve the continuity of the circuit; and a
current of comparatively low tension can be used, thus avoiding largely the danger
of fire or accident.
This is accomplished by placing each are lamp in a multiple are or derived circuit
from two main conductors, the divided circuit being completed only through the
electrodes of the lamp. A shunt circuit around the arc is not employed.
A suitable regulating mechanism for each lamp is employed, that hereinafter
described being preferred. A "safety catch"; (or piece of material weaker than
the rest of the circuit) which burns out when there is a definite increase in the
current above the normal flow, is preferably placed in each multiple are circuit to
prevent the injury liable to occur from the formation of a short circuit. A resistance,
in addition to that of the coils of the regulating magnet or solenoid, may be used,
and a circuit controller can also be placed in each multiple are circuit for making
and breaking the circuits of individual lamps.
By this arrangement no automatic cut-out devices are required for the lamps,
since the breaking of the circuit at a lamp does not materially affect other lamps,
and for this reason lamps can be adjusted, repaired, or replaced while others in the
same system are in operation. A current of low tension can be employed, and in a
large system a great saving in conductors can be made.
The regulating mechanism, especially adapted for lamps arranged in this manner,
is composed principally of two opposing solenoids or electro-magnets, arranged one
in a main conductor and one in the derived lamp-circuit. These solenoids or electro-
magnets act oppositely upon the same core or armature, or on separate cores or
armatures which oppose each other in their action upon the gripping-eye or other
suitable device. These solenoids or electro-magnets may be of the same resistance,
in which case the one in the derived lamp-circuit has a greater weight of copper
in its coils than that in the main conductor; or the latter may be of higher
resistance than the former. A shunt circuit may or may not be formed around the
solenoid or electro-magnet in the main conductor to lessen the resistance of such
conductor.
When the carbon electrodes are together the solenoid or electro-magnet in the
derived lamp-circuit predominates and raises the upper or positive carbon so as to
form the arc.
As the arc increases, this solenoid or electro magnet weakens until
the one in the main conductor overcomes its sustaining power, when the carbon
electrode drops to the proper point.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas John Handford in the Great Seal Patent Office on the
2nd November 1882.
THOMAS JOHN HANDFORD of 42 Southampton Buildings in the County of
Middlesex Patent Agent IMPROVEMENTS IN OR RELATING TO ELECTRIC LIGHTS"
a communication from abroad by Thomas Alva Edison of Menlo Park in the State
of New Jersey United States of America.
The said Invention relates to the description of Electric lights which are known
as arc lights and in particular to the regulating mechanism of the same.
The nature of the said Invention and the mode of carrying out the same will be
perfectly understood from the following description reference being had to the
several figures on the sheet of drawings hereunto annexed which are views
principally diagrammatic illustrating the said Invention.
One part of the said Invention relates to the combination in regulating mechanisın
of two opposing electro-magnets or solenoids of the same or approximately the
same resistance but of different weights (that is to say having different weights of
metal in their coils) located one in the main line and the other in a shunt around
the arc and of a shunt circuit formed around the electro-magnet or solenoid in the
main line.
This part of the said Invention is illustrated in figure 1 of the drawings. M and
M' are two electro-magnets (or they may be solenoids) of the same or approximately
the same resistance. The former is located in the line 1, 2 in which are also the
carbon electrodes C C¹ of the lamp and the latter is located in a shunt circuit 3, 4
which is formed around the arc or the carbon electrodes. A shunt circuit 5, 6,
with a small resistance R is formed around the electro-magnet or solenoid M such
circuit being joined to the line immediately on opposite sides of the connection of M
therewith. The electro-magnet (or solenoid M while of the same resistance as M'
has a greater weight of copper in its coils. When M and M¹ are electro magnets
as in the example illustrated they act oppositely upon a stationary core B. The
armature A is carried by a lever A' which works a gripping eye bor other suitable
device for lifting the upper or positive carbon electrode C to form an arc and for
regulating the feed of such carbon electrode. When M and M' are solenoids they
may act upon the same movable core which can be connected directly with the lever
or arm that works the gripping eye.
When C and Care in contact M predominates and lifts C so as to form the
arc. When the arc increases to a definite degree M' counteracts the sustaining
effect of M and C is allowed to drop until again arrested by M. The low resistance
shunt circuit 5, 6 reduces the resistance of the main line and allows the current to
flow freely to the lamps.
With
Another part of the said Invention which is illustrated in figure 2 relates to the
combination with a lower stationary carbon electrode and an upper movable
carbon electrode fed downwardly by gravity, of an electro magnet located in a
shunt around the arc and a permanent magnet, such electro and permanent magnets
acting oppositely upon an armature controlling the feeding mechanism.
reference to that figure, 1, 2 represents the main line in which are located the
carbon electrodes CC of the lamp. In a shunt circuit 3, 4 around the arc and
such carbon electrodes is located an electro magnet M'. To the upper end of the
soft iron core B of the electro magnet is attached one end of a permanent steel
magnet M which acts on such soft iron core oppositely to the action of the current
flowing through the coils of M. the armature A is connected by a lever A' or other
means with a gripping eye b or other suitable device for forming the arc and
regulating the feed of the upper carbon electrode. When C and C₁ are in contact

page_text: M predominates and lifts C forming the arc. When the arc increases to a definite
degree M' receives sufficient strength to counteract the effect of M and C drops a
short distance. The feed in this manner is made a continuous one.
Another part of the said Invention relates to the employment as one of the
opposing elements of the regulating mechanism, of a heating coil enclosed in an
expansible chamber, and the combination with such heating coil located in a shunt
around the arc of an opposing electro magnet or solenoid in the main line.
This part of the Invention is illustrated in figure 3 of the drawings-1, 2
represent the main line in which are located the carbon electrodes P N. In the
main line is also located an electro-magnet (or it may be a solenoid) M.
In a
shunt 3, 4 around the are is located a heating coil H which is inclosed in a tight
chamber H having an expansible end C. A rod s attached to this expansible end
may be the movable core of a solenoid or when M is an electro magnet (as in the
example illustrated) the said rod may pass through its core to the armature A the
movement of which works the gripping eye R or other suitable device. By these
means the heating coil is made one of the opposing elements of the regulating
mechanism. When P and N are in contact M predominates over the pressure
exerted by the heated air in C and lifts P so as to form the arc. When the arc
increases to a definite extent the heating coil increases in temperature te such an
extent that it overcomes M. and the upper or positive carbon electrode is allowed
to drop to the proper point.
Another part of the said Invention relates to the combination with voltaic arc
lamps arranged in separate multiple arc or derived circuits which are completed
through the electrodes of the lamps only, of regulating mechanisms each having as
opposing elements two electromagnets or solenoids located one in a main conductor
and the other in the multiple arc or derived lamp circuit.
This part of the said Invention is illustrated in figure 4 which is a diagrammatic
view of two arc lamps embodying the same. 1. 1, and 2, 2, are the main conductors
in separate multiple arc or derived circuits 3, 4 from which are located the carbon
electrodes C C of the arc lamps. One lamp is placed in each derived circuit which
is only completed through the carbon electrodes of the same no shunt circuit
around the are being employed. A "safety catch" S may be used in each lamp
circuit to break the circuit when a
cross or short circuit occurs therein.
resistance in addition to the coils of the regulating magnet or solenoid may be used
and also a circuit controller in each lamp-circuit but the manner of applying those
devices will be well understood and hence they are not shown.
"
"
A
a low
The regulating mechanism for each lamp is composed essentially of two oppositely
acting solenoids (or they may be electro magnets) M M¹ the former being located
in one of the conductors 1, 2, (it being shewn in 1 in the example illustrated) and
the latter in the lamp circuit 3, 4. M and M may be of the same resistance in
which case M' would have a greater weight of copper in its coils than M: or M
may be of greater resistance than M¹. In either case a shunt 5, 6 having
resistance R may or may not be formed around the coils of M. When M and M¹
are solenoids (as in the example illustrated) they act oppositely upon the same
movable core A which works a gripping-eye b or similar device.
When C and C
are in contact M¹ predominates and lifts Ċ forming the arc. As the arc increases
M overcomes the sustaining force of M' and C drops to the proper point.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is:-
First In regulating mechanisms for voltaic arc lights the combination of two
opposing electro magnets or solenoids of the same or approximately the same
resistance but of different weights located one in the main line and the other in a
shunt around the arc, and of a shunt circuit formed around the electro magnet or
solenoid in the main line substantially as hereinbefore described.

page_text: Second The combination with a lower stationary carbon electrode, and an
upper movable carbon electrode fed downwardly by gravity, of an electro magnet
located in a shunt around the arc and a permanent magnet, such electro and
permanent magnets acting oppositely upon an armature controlling the feeding
mechanism, substantially as herein before described.
Third A voltaic arc lamp wherein one of the opposing elements of the
regulating mechanism is a heating coil inclosed in an expansible chamber
substantially as hereinbefore described.
Fourth In regulating mechanism for voltaic arc lights, the combination of an
electro-magnet or solenoid in the main line and a heating coil located in a shunt
around the arc and opposing the electro magnet or solenoid in its action substantially
as herein before described.
Fifth The combination with voltaic are lamps arranged in separate multiple
arc or derived circuits which are completed through the electrodes of the lamps
only, of regulating mechanisms each having as opposing elements two electro
magnets or solenoids located one in a main conductor and one in the multiple arc
or derived lamp circuit substantially as hereinbefore described.
In witness whereof I the said Thomas John Handford have to this my
Specification set my hand and seal this second day of November One
thousand eight hundred and eighty two.