IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1883

page_text: LETTERS PATENT to Philip Jolin and John Parsons both of the City of
Bristol for an Invention of IMPROVEMENTS IN ELECTRIC ARC LAMPS
V.
+-
PROVISIONAL SPECIFICATION left by the said Philip Jolin and John
Parsons at the Office of the Commissioners of Patents on the 23rd May
1883.
"
PHILIP JOLIN and JOHN PARSONS, both of the city of Bristol,
IN ELECTRIC ARC-LAMPS
"
"IMPROVEMENTS
This invention which relates to improvements in electric arc-lamps consists, first,
in the method of opening or striking the arc, secondly, in means whereby the
carbons are 'fed with steadiness and regularity as the points are consumed in giving
light, and, thirdly, in the method of cutting off or shunting the current from any
lamp of a series, and re-establishing the arc therein
Further improvements relate to devices for holding the carbons and the globes..
The opening or striking of the arc is effected by means of a double electro magnet
composed of two hollow electro magnets wound with coarse wire and having
movable cores either hollow or solid attached at their lower ends to a bar of iron
which carries a block normally bearing against one side of the upper carbon rod.
To this block is hinged a second block situated at the side of the carbon rod
opposite to the first mentioned block. Attached to the second block is one end of
a spring the other end of which lies in the space caused by slotting the frame of
the lamp, or between two stops formed on the frame. When, by the passing of the
current through the wires of the double electro magnet, the cores thereof are caused
to rise, the aforesaid spring is brought into contact with one edge of the slot or the
upper stop and so causes the carbon rod to be gripped between the two blocks and
raised accordingly."
.
To the iron bar aforesaid, a tube is attached free to slide vertically through the
lamp frame and embracing the carbon rod which also is free to travel vertically in
the tube. The cores of the double electro magnet are thus maintained perpendicular.
The said tube extends upwards through the upper plate of the lamp, and may be
furnished at the top with an adjustable nut whereby the degree of travel of the
.

page_text: cores may be regulated and the length of the arc governed. The carbon rod may
be gripped between the lower end of the said tube and the second block aforesaid,
or between the iron bar and the said block, and, in either of these cases, the first
block is dispensed with.
Instead of attaching the cores of the double electro magnet to an iron bar as
aforesaid, they may be connected to flat iron plates carried one at each end of a bar
of brass or other non-magnetic substance.
A loose iron armature suspended to the guide tube of the carbon rod is placed
below the said plates and is furnished with two blocks placed at opposite sides of
the carbon rod. In the normal position of the armature, that is to say, when no
current is passing through the double electro magnet, it is free from contact with
the iron plates above it and no gripping action is exerted on the carbon rod, but,
when the current passes, the armature is attracted to the plates, the carbon rod is
gripped between the blocks and the cores being drawn upwards, the arc is opened
or struck.
To effect steadiness and regularity in feeding the carbon point, or points when
both upper and lower carbons are designed to move, an electro magnet wound
with fine wire and insulated from the frame of the lamp is placed as a shunt either
across the terminals of the lamp or across the arc only, and above the upper end
of this electro magnet and carried upon the insulated frame thereof, is a vibrating
armature which, when the arc is of normal length is held away by a spring from
the core of the electro magnet. One end of the vibrating armature is. electrically
connected to the carbon or carbon rod either directly or through an electro magnet
wound with coarse wire and more particularly described hereinafter in reference to
the method of replacing a lamp in a series after having been cut off or the
current shunted therefrom.
The other end of the vibrating armature rests against an insulated contact piece
fixed above on the frame of the lamp. A further electro magnet, wound with
coarse wire and having a movable core, is electrically connected in the lamp in the
manner described below. It may be wound either with one wire or with two
wires. If wound with two wires, either of the following methods may be
adopted;
(a.), One wire may be first coiled, the other being coiled upon the first and in
the same direction; (b.), A layer of coils of each wire may be made alternately and
in the same direction; (c.), The wires may be coiled together and in the same
direction; (d.), The wires may be coiled separately throughout and in opposite
directions, the coils being made either separately throughout or in alternate layers;
or, (e.), The electro magnet may be fitted with a transverse partition, and the
wires be coiled from opposite ends, one wire being entirely coiled at one end, and
the other wire at the opposite end.
The electrical connection of this latter electro magnet is as follows:-
When wound with one wire only, the wire is connected at one end to the
-vibrating armature placed above the fine wire electro magnet, as aforesaid.
The other end of the wire is connected to the contact piece fixed above the
vibrating armature. When the vibrating armature is in contact with the contact
piece, a short circuit is consequently established on the coarse wire electro magnet.
When the latter is wound with two wires, one end of one of the wires, which may
be conveniently called the first wire, is connected to one terminal of the lamp or to
the double electro magnet aforesaid; the other end is connected to the vibrating
armature. One end of the other wire, which may be conveniently called the
second wire, is likewise connected to the said terminal of the lamp or to the
double electro magnet, and the other end to the contact piece. Thus, when the
vibrating armature is in contact with the contact piece, the circuits are completed
in both wires, but, when by the undue elongation of the arc, the vibrating
armature is attracted by the core of the electro magnet below it and drawn away
from the contact piece, the circuit of the second wire is broken. In order to effect
a short circuit of one of the wires where two are employed, the first wire is

page_text: SO
At
connected as above and the second is connected at one end to the contact piece
which is in this case placed below the vibrating armature to which the other end
of the second wire is connected. Thus, when the armature is drawn down and
makes contact with the contact piece, a short circuit of the second wire is
established, it being understood that when two wires are used they are
connected that the electric current flows through them in opposite directions.
such time as a short circuit of a single wire is established, or the circuits of two
wires are completed, or no short circuit is established when two wires are
employed, the movable core of the electro magnet remains at rest at its lowest
point within the coil, but, when by undue elongation of the arc the resistance of
the spring attached to the vibrating armature is overcome, the armature is
withdrawn from contact with the contact piece in the cases where the latter is
above, but is drawn to the contact piece when this is below, and if the electro
magnet is wound with one wire only, the short circuit is destroyed, and, if with
two wires, the circuit of the second wire is broken or a short circuit of the second
wire is established, and in each of these cases the movable core is caused
to rise.
The core of the coarse wire electro magnet is connected at its lower end to the
arm of a platform free to oscillate upon a pivot upon which the said platform is
so adjusted that when the core is depressed to its lowest point, a ring or washer
supported in a recess formed in the platform, lies evenly in a horizontal plane and
does not bear upon the carbon rod which passes through it. To assist in main-
taining the ring or washer in the desired horizontal position, it is made to bear
against a stop or stud by means of a spring.
As the core rises, the platform is tilted and the ring or washer is thus made to
exert a downward pressure on the carbon rod which is thereby steadily and
regularly depressed. Instead of the platform aforesaid, a flat plate, free to oscillate
on a pivot and normally lying evenly in a horizontal plane, may be connected to
the core of the electro magnet. The spring aforesaid tends to maintain the ring
or washer in position against the said plate and the stop aforesaid. As the core
rises, the plate is tilted and the carbon rod depressed.
Instead of the electro magnet wound with fine wire herein before mentioned as
placed as a shunt either across the terminals of the lamp or across the arc, an
electro magnet wound with fine wire, and having a movable core and connected
in either of the ways mentioned in reference to the aforesaid fine wire electro
magnet, may be used. The core, movable as aforesaid, of the fine wire electro
magnet is attached at its upper end to a lever pivotted to the lamp frame.
A second lever, secured on the same pivot as the first, is connected thereto by a
friction joint.
These levers are electrically connected in the same manner as the vibrating
armature herein before referred to, the second lever normally resting against the
contact piece. At the passage of the current, a proportion thereof flows through
the fine wire electro magnet with movable core, and the core and the first lever
become drawn downwards to the degree governed by the tension of a spring,
one end of which is attached to the first lever and the other end to the lamp
frame.
When the arc becomes abnormally long and its resistance irregular, the first
lever is caused to vibrate and the vibratory motion becomes communicated to the
second lever. Thus, if the coarse wire electro magnet has one wire only, a short
circuit is, by the above action destroyed and established therein, and if the coarse
wire electro magnet has two wires, the circuit of the second wire is broken and
made.
Cutting off or shunting the current from the carbons of a lamp in which from
any cause the carbons have become defective, is effected by the arrangement and
in the manner following.
The lower pole of the fine wire electro magnet placed as a shunt across the
terminals of the lamp or across the arc, is extended downwards below its frame in

page_text: the form of a pole piece. To the frame is pivotted an insulated L shaped lever
one limb of which is of brass or other non-magnetic substance and the other of
iron. The iron limb of this lever extends below the pole of the electro magnet
and is thus a second armature thereof. A flat iron bar pivotted at one end to an
insulated jaw piece and having at its other end a projection forming a right angle
to the bar, is so arranged that when the iron limb of the L shaped lever aforesaid
is at its lowest point the said projection of the bar rests upon the non-magnetic
limb of the shaped lever. When, from any cause, the arc becomes abnormally
long, the iron limb of the L shaped lever is raised, the brass limb thereof moves
through a part of a circle and from under the projection of the bar, whereby the
latter makes contact with a contact piece connected to one of the terminals of the
lamp. A spring attached to the bar ensures the said contact. The bar is connected
either directly or through a suitable resistance with the other terminal of the lamp.
Thus, should contact occur between the bar and the contact piece connected, as
aforesaid, to a terminal of the lamp, the current passes through the said terminal,
contact piece and bar electrically connected to the other terminal, so that an
independent path is provided for the passage of the current.
In order to re-establish the flow of the current through the proper path 'to
re-form the arc as the carbons make contact, the following arrangement is used.
A coarse wire electro magnet, one end of the wire of which is connected to the
frame of the fine wire electro magnet and the other end to the frame of the lamp,
is placed directly over the bar aforesaid.
To the armature of the double electro magnet by which the arc is opened. or
struck, is attached a contact piece which, when the armature is raised to open or
strike the arc, is brought into contact with a metallic projection attached to the
insulated frame of the fine wire electro magnet. When the carbon points are
made to touch each' other, the current is diverted from the independent path
aforesaid, and a proportion thereof flows through the double electro magnet,
through the coarse wire electro magnets, the carbons and the frame of the lamp.
The bar herein before mentioned, as pivotted to an insulated jaw piece, rises
from contact with the contact piece also aforesaid, and the non-magnetic arm of
the shaped lever falls below the projection on the bar. The whole current then
flows through the double electro magnet, the two coarse wire electro magnets, the
carbons and the lamp frame.
The armature of the double electro magnet consequently rises and the contact
piece thereon makes contact with the metallic projection attached to the insulated
frame of the fine wire electro magnet. A short circuit is thus established on the
coarse wire electro magnet hereinbefore described as being connected to the
frame of the fine wire electro magnet and to the frame of the lamp. The bar is
thus allowed to fall upon the brass limb of the L shaped lever, the arc becoming
re-established.
Where a fine wire electro magnet with movable core is employed and placed, as
herein before mentioned, as a shunt across the terminals of the lamp or across the
arc, a fine wire electro magnet is substituted for the lengthened pole of the electro
magnet influencing the L shaped lever of the cut off mechanism, and is connected
in series with the fine wire electro magnet with movable core, the two forming
a shunt on the terminals or are of the lamp.
In adapting this invention to the employment of two pairs of carbon points in
à lamp, the cores of the double electro magnet are made hollow. The carbon rods
are passed and guided through the cores and the carbons are gripped by means of
the mechanism hereinbefore described with reference to single rod lamps, but so
adjusted that one pair of carbons is separated before the other, the arc being struck
or established at the last pair separated.
The guide tube described as employed with a single carbon rod is dispensed with
and in lieu thereof a wire is used, having an adjustable nut at the upper end to
regulate the length of the arc. This wire is attached to the armature which may
be detached from the cores of the double electro magnet and be furnished with

page_text: the gripping blocks for raising the carbon rods, the arrangement being such―
that on the armature being attracted, the rods are gripped between it and the
blocks.
The arrangement for feeding the carbon rods where two pairs of carbon points
are used is as follows. Each carbon rod has a corresponding oscillating platform
or plate as herein before described with reference to a single rod lamp, and from
each platform or plate projects an arm extending towards the coarse wire magnet
with movable core. By the action of the springs the said arms are caused, when
the rings or washers are not depressed, to rest upon stops fixed to the frame of the
lamp, so that the rods are free to slide vertically. The platforms or plates are
prevented by projections formed thereon at the sides nearest the rods, from
approaching each other, but they are free to oscillate on a rod or spindle held
between two blocks attached to the frame of the lamp, against which blocks the
platforms are respectively retained. On the same rod or spindle, but independent
of the two platforms, is pivotted a plate having two arms extending on each side
in the direction of the oscillating platform. This plate is connected to the movable
core of the coarse wire electro, magnet. When the said plate is equidistant from
the platforms, no. influence is exerted by the arms on either of the platforms, but,
on being caused to approach one or other of them, a corresponding motion is
imparted to the platform approached and the carbon rod on that side is fed
accordingly. The motion of the plate, situated as aforesaid between the platforms,
is communicated from one platform to the other in the manner following. A wire,
at the upper end of which is formed a fork and the lower end of which extends
downwards through the plate aforesaid, is pivotted at or near the middle to the
frame of the lamp or to a projection provided for the purpose. At the upper end
of the carbon rod carrying the carbon point by which the arc is first struck, is a
cap or button in which is cut a recess.
As the carbon point on which the arc is first struck or opened is being fed, the
carbon rod slides easily downwards between the extremities of the aforesaid fork,
but, when the carbon point is consumed, the cap or button on the upper end of the
carbon rod exerts a pressure on the fork which thereby becomes partially drawn
into the recess cut in the said cap or button. The centre plate is thus brought
into such position that the feed is arrested. Thereupon the arc becoming
lengthened, the cut off arrangement comes into action and the rods are
released.
The rod having the cap or button exerts a pulling action on the fork and the
centre plate is moved thereby to the position opposite to that which it previously
occupied. The arc striking mechanism again lifts both carbon rods, but as the first
pair of carbon points are not in contact, the arc is struck or opened on the second
pair.
Cutting off and relighting lamps with two or more pairs of carbon points
are effected in a manner similar to that described for a single rod lamp.
Lamps constructed under this invention are adapted to burn at any angle, the
feeding of the carbon points being effected mechanically. When placed at an
angle, springs are employed to pull or push the cores from out the double electro
magnet and the coarse wire electro, magnet herein before mentioned as capable of
being wound in various ways. Where-the fine wire electro magnet is used to
actuate the cut off mechanism, it is preferably placed so that the iron limb of
the L shaped lever naturally lies horizontally. The iron limb may, however, be
kept away from its pole piece by means of a spring.
Where the fine wire electro magnet with movable core is used in the feeding
arrangement, it is vertically placed to ensure unopposed vertical travel of
the core.
The construction of the mechanism permits of adaptation of the lamp for
currents of high or low tension.
The carbon holder as constructed under this invention consists of two metal
leaves or plates embracing the carbon and engaging with one another at one side
.

page_text: by having the edges turned to form over lapping hooks. Instead of the hooks, a
lug may be formed on each leaf, the lugs being drilled to receive a pin. On the
opposite side to the hinge thus formed the leaves or plates are secured by a
clamping screw or other device by which the grip is regulated.
The globe holder as constructed under this invention is in two parts which are
secured together when in place, a ring of india rubber being interposed between
the edges of the holder and the rim of the globe. The holder is free to slide
vertically on a centre rod upon which it may be clamped or otherwise secured at
any desired height.
This rod, which may carry the lower carbon holders, is of such section that the
globe holder is prevented from turning thereon. The globe holder is pierced to
permit of its being lowered without interference with the carbons.
Manipulation of the carbons is thus readily effected, and there being no hole at
the bottom of the globe, falling of heated carbons is obviated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Philip Jolin and John Parsons in the Great Seal Patent Office on the
22nd November 1883.
PHILIP JOLIN and JOHN PARSONS both of the City of Bristol IMPROVEMENTS
IN ELECTRIC ARC LAMPS
Our said invention, which relates to improvements in electric are lamps, consists
first, in the method of opening or striking the arc; secondly, in the means whereby
the carbons are fed with steadiness and regularity as the points are consumed in
giving light, and thirdly, in the method of cutting off, or shunting the current
from, any lamp of a series and re-establishing the arc therein. Further improve-
ments relate to an improved device for holding the carbons, and to an improved
gallery or globe holder.
The opening or striking of the arc is effected by means of a double electro-
magnet composed of two hollow electro-magnets wound with coarse wire and
having movable cores, either hollow or solid, attached at their lower ends to a bar
of iron carrying a block normally resting against one side of the upper carbon rod.,
To this block is hinged a second block situated at the side of the carbon rod.,
opposite to the first. block. Attached to the second block is one end of a spring
the other end of which lies in the space caused by slotting the frame, or between
two stops. When, by the passing of the current through the wires of the double
electro-magnet, the cores thereof are caused to rise, the aforesaid spring is brought,
into contact with one edge of the slot, or the upper stop, and the carbon rod is
thus caused to be gripped between the two blocks and raised accordingly. To the,
iron bar aforesaid a tube is attached, free to slide vertically through the lamp
frame and encircling the carbon rod which also is free to travel vertically in the
said tube.
The cores of the double electro-magnet are thus maintained perpendicular. The
tube aforesaid extends upwards through the upper plate, of the lamp frame and
may be furnished at the top with an adjustable nut whereby the degree of travel..
of the cores may be regulated and the length of the arc governed. The carbon
rod may be gripped between the lower end of the said tube and the second block..
aforesaid, or between the iron bar and the said block. In either of the two latter,
cases the first block is dispensed with.
:
Instead of attaching the cores of the double electro-magnet as aforesaid, they
may be connected to flat iron plates united by an intervening plate of brass or',
other non-magnetic substance. A loose iron armature, carried at the lower end of,
the guide tube of the carbon rod, is placed below the said plates and is furnished
with two blocks placed at opposite sides of the carbon rod. In the normal position..
of the armature, that is to say when no current is passing through the double.
electro-magnet, it is free from contact with the iron plates above it and no gripping
action is exerted on the carbon rod; but, when the current commences to flow, the,
armature is attracted to the plates, the carbon rod is gripped between the blocks,,
and, the cores being drawn upwards, the arc is opened or struck.
:
To effect steadiness and regularity in feeding the carbon as it is consumed in,
giving light, an electro-magnet, wound with fine wire and insulated from the.
frame of the lamp, is placed as a shunt either across the terminals of the lamp or;
across the are only, and above the upper end of this electro-magnet, and carried,"
upon the insulated frame thereof, is a vibrating armature which, while the arc is,
of normal length, is held away by a spring from contact with the core of, the..
electro-magnet. One end of the armature is electrically connected to the carbon,.

page_text: or carbon rod either directly or through an electro-magnet wound with coarse wire
and again hereinafter referred to in connection with the method employed to
re-place a lamp in a series after having been cut off or having had the current
shunted therefrom. The other end of the armature is in contact with an insulated
contact piece fixed above on the frame of the lamp.
J
Another electro-magnet, wound with coarse, wire and having a movable core, is
electrically connected in the lamp" in the manner described below. It may be
wound either with one wire or with two wires.
"
1621%
If wound with two wires, either of the following methods may be adopted.
(a): One wire may be first coiled, the other being coiled upon the first and in the
same direction. (b) A layer of coils of each wire may be made alternately and in
the same direction. (c) The wires may be coiled together and in the same
direction. (d) The wires may be coiled separately throughout and in opposite
directions, the coils being laid on either separately throughout or in alternate
layers. (e) The electro-magnet may be fitted with a transverse partition and the
wires coiled from opposite ends, one wire being entirely coiled at one end, and
the other at the opposite end. The electrical of this latter electro-magnet is as
follows: When wound with one wire' only, the wire is connected at one end to
the vibrating armature above the fine wire electro-magnet; the other end is
connected to the contact piece above the armature.
While the armature remains in contact with the contact piece a short circuit is
consequently established on the coarse wire electro-magnet. When the latter is
wound with two wires, one end of one of the wires, which may be conveniently
called 'the first wire, is connected to one terminal of the lamp or to the double arc-
striking electro-magnet; the other end is connected to the vibrating armature.
One end of the other wire, which may be conveniently called the second wire, iś
likewise connected to the said terminal of the lamp or to the arc-striking electro-
magnet, and the other end to the contact piece.
Thus, while the vibrating armature is in contact with the contact piece, the
circuits are completed in both wires, but when, by the undue elongation of the
arc, the vibrating armature is attracted to the core of the electro-magnet below it
and drawn away from the contact piece, the circuit of the second wire is broken.
In order to effect a short circuit of one of the wires, where two wires are employed,
the first wire is connected as above and the second wire is connected at one end
to the contact piece which is, in this case, placed below the vibrating armature to
which the other end of the second wire is connected.
When, therefore, the armature is drawn down and makes contact with the
contact piece, a short circuit of the second wire is established, it being understood
that when two wires are used they are so connected that the current flows in
opposite directions in the different wires.
At such times as a short circuit of a single wire is established, or the circuits of
two wires are completed, or no short circuit is established where two wires are
employed, the movable core of the electro-magnet so wound remains at rest at its
lowest point within the coil, but when, by undue elongation of the arc; the
résistance of the spring attached to the vibrating armature is overcome, the arma-
ture is withdrawn from contact with the contact piece in the case of the latter
being above, but drawn down to the contact piece when this is below. If the
coarse wire electro-magnet is wound with one wire only, the short circuit is
destroyed, and if with two wires, the circuit of the second wire is broken or a
short circuit of the second wire is established; and in each of these cases the
movable 'core is caused to rise. The core is connected at its lower end to the
arm of a platform free to oscillate upon a pivot upon which it is so adjusted
that when the core is depressed to its lowest point, a ring or washer, supported
in a recess formed in the platform, lies evenly in a horizontal plane and does not
impinge upon the carbon rod which it encircles. To assist in maintaining the
ring or washer in the desired horizontal position, it is made to bear against a stop
or stud by means of a spring: As the core rises, the platform is tilted and the

page_text: ring or washer is thus made to bear against, and exert a downward pressure on,
the carbon rod which is thereby steadily and regularly depressed.
Instead of the platform aforesaid, a flat plate free to oscillate on a pivot and
normally lying in a horizontal plane, may be connected to the core of the
electro-magnet. The spring aforesaid tends to maintain the ring or washer in
position against the said plate and the stop aforesaid. As the core rises, the plate
is tilted and the carbon rod depressed.
Cutting off, or shunting the current from the carbons of, a lamp of a series is
effected in the manner following. The lower pole of the aforesaid electro-magnet
wound with fine wire is extended downwards below its frame in the form of a
pole piece. To the frame is pivotted an insulated L shaped lever one limb of
which is of brass or other non-magnetic substance, and the other of iron. The iron
limb of this lever extends below the pole of the electro-magnet and is a second
armature thereof. A flat iron bar, pivotted at one end to an insulated jaw piece
and having at one end a projection formed at or nearly at a right angle to the bar,
is so placed that when the iron limb of the L shaped lever is at its lowest point,
the said projection on the bar rests upon the non-magnetic arm of the lever.
When the arc becomes abnormally lengthened, the iron limb of the L shaped lever
is attracted upwards and the brass limb thereof is moved from under the projection
of the bar, whereby the latter makes contact with a contact piece connected to one
of the terminals of the lamp. The bar is connected, either directly or through a
suitable resistance, with the other terminal of the lamp. On the contact of the
bar with the contact piece, the current passes through the terminal of the lamp
to which the contact piece is connected, and through the bar to the other terminal.
In order to re-establish the flow of the current through the proper path to
re-form the arc, the following arrangement is adopted. A coarse wire electro-
magnet, hereinbefore referred to as electrically connecting the armature of the fine
wire electro-magnet and the carbon rod, is placed directly over the bar aforesaid.
To the armature of the arc-striking electro-magnet is attached a contact piece
which, when the armature is raised to open or strike the arc, is brought into
contact with a metallic projection attached to the insulated frame of the fine wire
electro-magnet. When the carbons are made to touch each other the current is
diverted from the independent path aforesaid and a proportion thereof flows
through the arc-striking electro-magnet, the coarse wire electro-magnets, the
carbons and the frame of the lamp. The bar above the L shaped lever rises from
the contact piece upon which it rested and the non-magnetic limb of the lever
resumes its first position. The whole current then flows through the arc-striking
electro-magnet, the two coarse wire electro-magnets, the carbons and the lamp
frame.
The armature of the arc-striking electro-magnet consequently rises and the
contact piece thereon makes contact with the metallic projection attached to the
insulated frame of the fine wire electro-magnet.
A short circuit is thus established on the coarse wire electro-magnet hereinbefore
described as being connected to the frame of the fine wire electro-magnet and to
the frame of the lamp, and the bar falls on to the non-magnetic limb of the
L shaped lever, and the arc becomes re-established.
In adapting our said invention to lamps having two pairs of carbon points, the
cores of the double electro-magnet are made hollow. The carbon rods, which are
passed through and guided in the cores, are gripped by means of the mechanism
berein before described with reference to single rod lamps, duplicated and so
adjusted that the separation of one pair of carbons before the other is ensured.
The guide tube described as employed with single rod lamps is dispensed with and
instead thereof a wire is used having an adjustable nut at the upper end to regulate
the length of the arc. This wire is attached to the armature which may be
detached from the cores of the double electro-magnet and be furnished with the
gripping blocks for raising the carbon rods, the arrangement being such that, on
the armature being attracted, the rods are gripped between it and the blocks. The.

page_text: carbons are fed by means of mechanism similar to that herein before described,
tilting platforms being placed opposite the carbon rods and lying at one side on the
rings or washers, and, on the other, normally resting on stops provided therefor.
Upon the same spindle as the platforms, is carried a plate free to be moved
laterally and having an arm extending horizontally on each side. When this plate,
which is connected to the core of the coarse wire electro-magnet above it, is equi-
distant from the two platforms the latter are at rest, but when an arm of the
sliding plate is below a platform the latter is tilted and causes the ring on which
it rests to depress the carbon rod. A wire or rod, at the upper end of which is a
fork or jaw and the lower end of which extends downwards through the sliding
plate, is pivotted to the lamp frame or to a projection provided for the purpose.
At the upper end of the carbon rod carrying the carbon at which the arc is first
struck is a cap or button having a recess or neck formed below it. This carbon
rod slides easily downwards, as it is fed, between the extremities of the fork and,
when the carbon is consumed, the cap or button presses on the fork which thereby
becomes partially drawn into the recess or neck.
The sliding plate is by these means moved towards the opposite carbon rod and
the feeding action is arrested. Thereupon, the arc becoming unduly lengthened,
the cut off arrangement comes into action and the carbon rods are no longer
gripped. The sliding plate is moved to the position opposite to that which it
occupied when the first carbon rod was being fed. The arc-striking mechanism
again lifts the rods, and the arc is opened or struck on the side opposite to that at
which is the rod having the cap or button.
Cutting off and re-lighting lamps with two or more pairs of carbons are effected
in a manner similar to that described for a single rod lamp.
And in order that our said invention may be properly understood, we now
proceed more particularly to describe the same with reference to the accompanying
sheets of illustrative drawings and the figures and letters marked thereon.
Fig. 1, sheet 1 of the drawings, represents a side elevation of a double rod
electric arc lamp constructed substantially in accordance with our said invention.
Figs. 2, 3 and 4 are respectively, a plan, rear and front elevation of the 'lamp.
The opening or striking of the arc is effected through the double electro-magnet
composed of the two hollow electro-magnets A and B wound with coarse wire
and having movable cores a and b, either hollow or solid, attached at their lower
ends to the armature C towards each end of which are secured blocks d and e
the inner V-shaped faces of which lie against the carbon rods D and E, as seen
more particularly at Figs 1 and 2. To the blocks d and e are hinged the blocks f
and g placed at the opposite sides of the carbon rods D and E. Attached to the
blocks and g are the flat springs fl and g¹ the outer ends of which extend
through slots formed to receive them in the brackets f² and g².
When, by the passing of the current through the wires of the electro-magnets A
and B, the cores a and b are caused to rise, the outer ends of the springs fl and gl
being retained in the slots aforesaid, the carbon rods D and E become gripped
between the blocks d and e and ƒ and g, and are raised accordingly, it being
understood that the adjustment of the springs f¹ and g¹ provides for the gripping
of the carbon rod D in advance of the carbon rod E. The carbon rods are passed
through the cores a and b, and the armature C is suspended from the upper plate
of the lamp frame by the rod c having an adjustable nut c¹ whereby the length
of the arc is regulated.
In the modification of the means of opening or striking the arc wherein a
loose iron armature suspended below metallic plates united by a non-magnetic
substance is employed, the arrangement illustrated at Fig. 5, sheet 1, is preferred
to that herein before described.
Instead of the blocks referred to as placed at opposite sides of the carbon rods,
the cores a and b of the electro-magnets A and B are furnished with the ferules or
bushes e and f extending downwards from the metallic magnetic plates or pole
pieces F and Ġ, united by the intervening non-magnetic plate H, through suitable,

page_text: holes formed in the armature C which is further slotted to receive the tongue o
projecting downwards from the pole pieces. Towards one end of the armature is
secured the spring k, as shown. At the opposite end of the armature is an
adjustable plate or spring recessed at the side next the carbon rod E to conform
to the shape thereof.
When influenced by the current, the plates F and G become oppositely
magnetised and attract the armature C, previously depending below the plates F
and G to an extent governed by the position of the nut r on the rod s to which
the united pole pieces are screwed. By the tongue o the armature C, as it rises,
is impelled towards the carbon rod E; the spring impinges upon the carbon
rod D which is thus gripped between it and the ferule e, and the carbon rod E is
then gripped in like manner between the plate or spring and the ferule f. The
are is thus opened or struck. The armature C may be coupled at one end to the
plate G.
To assist in the proper successive gripping of the rods the compound bar may
have pivotted on each side of it a lever the upper ends of which are made to
impinge against the underside of one of the electro-magnets, whereby the lower
ends are made to raise the loose armature.
Under another modification, specially applicable to single rod lamps, a plunger,
composed of one or more pieces of iron, is suspended within the carbon rod, as
represented at Fig 5º, sheet 1 of the drawings. When the current begins to flow,
the plunger a¹ is attracted to the hollow core a and the carbon rod d is gripped
between the plunger and the core and rises with them.
To effect steadiness and regularity in feeding the carbons, the shunt relay
electro-magnet H, wound with fine wire and insulated from the frame of the lamp,
is placed as a shunt across the terminals of the lamp. It may be placed as a shunt
across the arc only.
Above the electro-magnet H and pivotted to the insulated frame thereof, is a
vibrating armature h which, while the arc is of normal length, is held away from
the core of the electro-magnet H by the spring h¹. The armature his electrically
connected at its pivotted end to the carbon rods through the electro-magnet I
wound with coarse wire and hereinafter more particularly referred to in connection
with the method employed to replace a lamp in a series after having been cut out
or having had the current shunted therefrom. The other end of the armature h
rests against the insulated contact piece h³ fixed to a pillar of the lamp frame.
electro-magnet K, carried at the opposite side of the lamp and wound with coarse
wire and having a movable core k, is electrically connected in the lamp as
herein after described.
The
This electro-magnet K may be wound with either one wire or with two wires.
When wound with two wires, either of the following methods of winding may be
adopted. (a) One wire may be first coiled, and the other coiled upon it and in the
same direction. (b) A layer of coils of each wire may be made alternately and in
the same direction. (c) The wires may be coiled together and in the same
direction. (d) The wires may be coiled separately throughout and in opposite
directions, the coils being made either separately throughout or in alternate layers.
(e) The electro-magnet may be fitted with a transverse partition and the wires be
coiled from opposite ends to the partition, one wire being entirely coiled at one end
and the other wire at the opposite end. When wound with two wires the electro-.
magnet K becomes a divided differential shunt.
The electrical connection of the electro-magnet K is as follows:-
=
When wound with one wire only, as represented in the diagram, Fig 1, sheet 2
of the drawings, the wire is connected at one end to the armature h; the other
end to the contact piece h2, the respective ends being also connected one to the top
carbon rods and frame of the lamp through the electro magnet I, and the other
through the double electro-magnet A B to the terminal T. The terminal T¹ is
connected to the lower carbon rod. Consequently, while the armature h bears
against the contact piece h², a short circuit is established on the electro-magnet K...

page_text: When the latter is wound with two wires, as is to be understood of the lamp
illustrated at Sheet 1 of the drawings and represented in the diagram, Fig 2, sheet 2
thereof, one end of one of the wires 7, which may be conveniently called the first
wire, is connected to the electro-magnet B; the other end is connected to the
armature h. One end of the other wire m, which may be conveniently called the
second wire, is likewise connected to the electro-magnet B; the other end is
connected to the contact piece h². Thus, while the armature h bears against the
contact piece h², the circuits are completed in both wires, but when, by the undue
elongation of the arc, the armature h is attracted to the core of the electro-
magnet Hand drawn away from the contact piece h2, the circuit of the second
wire m is broken.
In order to effect a short circuit of one of the wires m, the connections are
arranged as represented in the diagram, Fig 3, sheet 2 of the drawings. The first
wire is connected as above, and the second wire m is connected at one end to a
contact piece h³ placed below the armature h to which the other end of the second
wire is connected, the respective ends of the second wire being also connected one
to the top carbon rods and frame of the lamp through, the electro magnet I, and
the other through the double electro-magnet A B to the terminal T., When the
armature h is drawn down to the contact piece h2, a short circuit of the second
wire is established, it being understood that the current flows through the two
wires in opposite directions.
Under an alternative arrangement, the core of the electro-magnet H is movable
and is attached at its upper end to a lever pivotted to the frame of the lamp.
A second lever secured on the same pivot as the first, is connected thereto by a
friction joint. These levers are. electrically connected in the same manner as
is herein before described with reference to the armature h, the second lever
normally resting against the contact piece h³. When the current passes, a
proportion thereof flows through the fine wire electro-magnet H, and the core and
the first lever become drawn downwards to the degree governed by the tension of
a spring one end of which is attached to the first lever and the other to the lamp
frame. When the arc becomes abnormally long and its resistance irregular, the
first lever is caused to vibrate and the vibratory motion becomes communicated to
the second lever. Thus the circuit of the second wire is broken and made. When
one wire only is employed, a short circuit is destroyed and established.
At such times as the circuits of the wires are completed, or no short circuit is
established, or when only one wire is used a short circuit is established thereon,
the core of the electro-magnet K remains at rest at the lowest point of its travel,
but when, by undue elongation of the arc, the resistance of the spring h¹ is over-
come, the armature h is withdrawn from the contact piece h2 and the circuit of the
second wire m is broken or a short circuit thereof is established. When one wire
only is used, the short circuit thereof is destroyed. In each of these cases the
core k is drawn upwards into the hollow electro-magnet K.
At its lower end the core k is connected by the link k¹ to the arm n of the
plate N free to oscillate or tilt in suitable bearings in which are also carried the
plates o and p placed opposite the carbon rods D and E and impinging upon
the rings O and P encircling the carbon rods, as seen more particularly at Fig. 6,
which represents a transverse section of the lamp taken below the various electro-
magnets.
The springs o and p₁ exert an upward pressure on the rings O and P below
which they are placed, and when the core k of the electro-magnet K is at its
lowest point, the rings O and P lie evenly in a horizontal plane and do not exert
any pressure on the carbon rods D and E. The stops o2 and p2 assist in
maintaining the rings O and P in the desired horizontal position.
At the back the plate N is fitted with two arms o³ and p³, one projecting
horizontally on each side towards the plates o and p which are prevented from
moving laterally. The arm o³ lies below a prolongation formed at one side of the
plate o.. When the core k of the electro-magnet -K rises, the plate ois tilted and

page_text: a downward pressure is exerted by the impinging of the ring O, tilted in the
reverse direction to the plate o, on the carbon rod E which is thus steadily and
regularly depressed as required.
When the carbons on that side of the lamp are consumed, the plate N is moved
to the opposite side to cause the carbon rod D to be similarly fed, in the manner
following. At the upper end thereof the carbon rod E is shaped to form a cap or
button, below which is cut a recess or neck, as shown. A rod q, carrying at its
upper end a fork Q, is pivotted upon the frame of the electro-magnet K. It may
be pivotted at any other convenient place. At its lower end the rod q enters a
slot formed in the plate N. The carbon rod E in being fed slides easily down-
wards between the extremities of the fork Q, but when the carbon it carries is
consumed, the cap descends on the fork Q which is thereby drawn towards the
carbon rod E and thus the plate N, at the bottom of the pivotted rod is impelled
towards the plate p. Feeding of of the carbon rod E is now arrested, the arc
becomes lengthened and the carbon rods are released from the grasp of the gripping
blocks d, f, e, g by the action of the cut off mechanism immediately hereinafter
described. The arm på of the plate N passes below the prolongation formed on
the plate p, and, upon the arc-striking mechanism again coming into action,
the arc is struck on that side of the lamp. The outer ends of the prolongations
of the plates o and p normally rest on suitable stops formed on the lamp frame.
Cutting off or shunting the current from a lamp is effected by the following
arrangement of mechanism.
The lower pole of the electro-magnet H is extended downwards in the form of a
pole piece.
Carried in a suitable bearing supported on the lower plate of the lamp frame is
the insulated L shaped lever R, one limb r of which is of brass or other non-
magnetic substance, and the other, r', of iron. The latter limb.extends below the
pole of the electro-magnet H and is thus a second armature thereof. The flat
bar S, pivotted and insulated at 8 and bent downwards at its inner end, rests upon
the non-magnetic limb r of the lever R, while the iron limb 1 is not attracted.
When, from any cause, the arc becomes excessively lengthened, the limb r of the
lever R is attracted and raised and the bar S, no longer supported' by the limb r,
falls on to the contact piece T3 connected to a terminal T¹ of the lamp.
Immediately over the said contact piece T2, the bar S is provided with a copper
stud to ensure a good contact. The spring s assists in maintaining the contact.
The bar S is connected to the other-terminal T of the lamp through the resistance s².
An independent path is thus provided for the passage of the current.
To re-
establish the flow of the current through the proper path to re-form the arc, the
electro-magnet I, wound with coarse wire having one end connected to the frame
of the electro-magnet H and the other to the lamp frame, is placed over the bar S
aforesaid. An insulating piece intervenes between the electro-magnet I and the
bar S. To the armature C of the arc-striking double-electro magnet A B is
attached a contact piece c³ which, when the armature C is raised to open or strike
the arc, is brought into contact with the arm V attached to the insulated frame of
the electro-magnet H. When the carbon points are made to touch each other, the
current is diverted from the independent path aforesaid and a proportion thereof
flows through the electro-magnets A. B. K and I, the carbons and the frame of the
lamp. The bar S rises from the contact piece T2 and the limb r of the lever R is
restored to its original position below the curved end of the bar S. The whole
current then flows through the electro-magnets A. B. K and I, the carbons and
the lamp frame; the armature Crises, the contact piece c² touches the arm V, and
a short circuit is established on the electro-magnet I; the bar S falls upon the
limb r of the lever R, and the arc becomes re-formed.
The wires of all or any of the electro-magnets of the lamp may be varied in size
to suit different currents.
The carbon holder as constructed in accordance with our.said invention consists
of the metallic semi-circular plates or leaves U and W embracing the carbons D₁

page_text: 'and E¹. The' leaves or plates U are screwed to the carbon rods D and E and
engage with the leaves or plates W at one side by means of the loose hinges formed
by turning the edges to overlap, as shown. On the opposite side they are held
together by clamping screws w, or their equivalent, by which the grip is regulated.
Figs. 7, 8 and 9, sheet 1, represent detached.views of the holder.
Fig 10, sheet 1, represents a vertical section, partly in elevation, of the gallery
or globe holder as constructed in accordance with our said invention. Fig 1l is a
plan of the same. It is made in two separate semi-circular sections which are
grasped and held together by the nut X. The ring x of india rubber is interposed
between the rim x of the gallery and the flange y of the globe Y to obviate
fracture. The gallery or holder is free to slide vertically on the central rod Z upon
which it may be arrested by the pin z passed through slots or holes in the rod
which is square or rectangular in section. The holder cannot turn round on the
rod. It is pierced or provided with openings which permit the free passage of
the carbons. Manipulation of the latter is readily effected and, there being no
opening at the bottom of the globe, danger from' the falling of heated carbon points
is obviated. The carbon holders consisting of the leaves Ū and W are constructed
similarly to those herein before described.
Having now described our said invention and the mode or manner in or under
which the same is or may be used or practically carried into effect, we claim as
the invention secured to us by the herein before in part recited Letters Patent.-
First The method of opening or striking the arc through successive gripping
of the carbon rods either between blocks hinged one to the other, or between
adjustable plates or springs carried on a loose armature suspended below a bar,
composed of magnetic plates united by a non-magnetic link, and ferules or thimbles
placed opposite to the said adjustable plates or springs, substantially as described
and shown.
Second Opening or striking the arc by gripping the carbon rods between the
hollow cores of the arc-striking electro-magnets and plungers suspended within
the rods.
Third-The method of feeding the carbons by rings embracing the carbon rods
and supported on springs, the rings being acted upon by tilting plates to exert a
downward pressure on the rods at such times as the arc becomes unduly lengthened,
substantially as described and shown.
Fourth-The use in an arc lamp of a a divided differential electro-magnet, sub-
stantially as described, enabling the said electro-magnet to be demagnetised and
magnetised without opening the main circuit.
Fifth The device of employing a comparatively feeble shunt electro-magnet
to work the feed mechanism by actuating a relay coil or coils interposed in the
main circuit.
Sixth Cutting off, or shunting the current from, the lamp by means of an
L shaped lever influenced by an electro-magnet, substantially in the manner
hereinbefore described, to divert the flow of the current through a pivotted bar and
contact piece to an independent path.
Seventh-Restoring the flow of the current to its normal path by means of the
bar referred to in claim sixth, the bar being subject to be influenced by an electro-
magnet and caused to rise from contact with the contact piece also referred to in
claim sixth and thus to restore the flow of the current to its normal path through
the lamp, substantially as herein before described and shown.
Eighth The employment of a plate free to slide laterally and actuated by a
forked rod to pass, when the carbon at one side is consumed, to the opposite side
whereby the tilting plate on the latter side is in turn made to feed the
corresponding carbon; the cut off mechanism having meanwhile been brought
into action and the arc again opened or struck, substantially as described and
shown.
Ninth The carbon holder constructed of two separate leaves or plates one of
which is secured to the carbon rod and engages with the other at one side by means
.

page_text: of the loose hinge formed by the folded edges, one overlapping the other. At the
other side a pinching screw regulates the grasp on the carbon, substantially as
described and shown.
Tenth The globe holder constructed in separable portions held together by a
nut or its equivalent and capable of being secured at desired positions on the rod
carrying it by means of pins or bolts passed through or in to corresponding holes or
slots, substantially as described and shown.
In witness whereof we the said Philip Jolin and John Parsons have hereunto
set our hands and seals this twenty first day of November in the year of our
Lord one thousand eight hundred and eighty three.
PHILIP JOLIN (L.S.)
JOHN PARSONS (L.S.)