IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by the said James Brockie at the Office*
of the Commissioners of Patents on the 4th May 1881.
"
JAMES BROCKIE, of Brixton, in the County of Surrey. IMPROVEMENTS IN
ELECTRIC ARC LAMPS."
This Invention refers to the particular construction and method of regulating
electric lamps, substantially as hereafter described, in order that they may operate
in a more perfect manner than hitherto, and also that when two or more lamps aro
placed in the same circuit, the arcs shall be regulated according to their individual
requirements, and at the same time to a very important extent according to the
strength of the current. For these purposes I employ two solenoids or magnets in
my improved lamps, one being placed in the main circuit, the other in a branch or
shunt across the arc. I am well aware that the employment of two such solenoids
in electric lamps is not new, but the relation to each other in which I place them,
the duties I impose upon them, and the mechanical combinations I operate by
means of them according to this Invention I consider novel, and to constitute a
radical improvement in electric lamps.
The first method of carrying out this part of my Invention will be better
understood by describing how it may be applied or adapted to existing lamps of
well known construction; take the lamp, for example, known as the "Serrin." In
this lamp the arc is first obtained by the direct action or pull of a magnet in the
main circuit, and the future regulation and feed of the carbons depends upon the
further action of this same magnet, by its allowing the escape of a feeding train of
wheels as the current weakens by the consumption of the carbons. Now according
to this Invention I employ the second magnet or solenoid which is in the shunt
bridging the arc, to release, retard, or stop the feeding train; but at the same time
the main magnet or solenoid plays an all important part in the action of the said
second or shunt magnet, to wit, the tightening or slacking of the spring against
C

page_text: which the second solenoid acts, so that when a strong current exists in the main
circuit, the main magnet in addition to directly enlarging the arc (as in the
"Serrin" lamp), will pull or tighten the said spring, and when a weak current
passes it will slacken the said spring; in fact, the tention or strength of the feeding
spring against which the shunt magnet acts will depend upon and be automatically
regulated by the strength of the main current through the agency of the magnet
in the main circuit. This feature constitutes the novel element in this part of the
Invention, the advantage of which when compared with existing methods of using
two such solenoids will be seen; the said comparison will also shew more clearly
the action of my improved apparatus. Compare, for instance, the well known
"Siemens" (Alteneck) or the "Brush." differential coil lamps, which work with
two solenoids either in direct mechanical or magnetical antagonism; suppose such
lamps are duly burning, the main current is now, say, weakened by any cause, as
for example, lamps being put in circuit, or change of speed, both solenoids will be
weakened equally or practically so, therefore as the solenoids counteract each other,
the position of the carbons will remain the same; again, on the other hand, should
the main current be increased by any cause, both coils will strengthen equally, but
no change will take place in the position of the carbons, the feed or regulation
being permitted only when one solenoid or coil overpowers the other, therefore the
arcs in such lamps remain constant to a great extent, whether the main current is
strong or the reverse. Now by arranging the two solenoids or magnets according
to this Invention, as described, the improved action is as follows:-Suppose the
lamps are duly burning, the main current is now diminished by some such cause,
as before suggested, the main circuit solenoid will therefore by its weakening
reduce the tension of the feeding spring, which will compensate for the necessitated
weakening of the shunt solenoid, and at the same time bring the lower carbon a
little closer to the upper, thus at once reducing the size of the arc, and adjusting
the feeding gear to the new or reduced strength of current; the opposite of all
this will take place should the main current strengthen and so a larger are will
at once be struck, and the feeding spring automatically adjusted to the new state
of things by the direct action of the main circuit magnet or solenoid.
The second method of carrying out this Invention consists in employing the two
solenoids or magnets to operate directly upon the carbon holder by means of a
clutching device, which device may be of various construction, but whatever its
construction it will be operated upon by the two solenoids; substantially in the
following manner, and with the following results:-In such lamp the upper carbon
holder is free to fall by its own weight, but is preferably retarded by a "dash pot,"
train of gearing, or equivalent arrangement as in most electric lamps, the lower
holder is preferably stationary. I arrange the two solenoids in line on either side
of the moving holder, so that it occupies a position between the two coils. The
clutch above spoken of may consist of a plate of metal having an opening in it just
large enough to allow the carbon holder to pass freely through it. This plate is
placed in line with the two solenoids and holder, so that one end of it is opposite
the main solenoid, and the other extremity opposite the shunt solenoid; the cores
or armatures of the two solenoids engage the two ends of the said plate or clutch,.
which may thus be lifted or depressed by their action, that is to say, the plate
may be tilted up at either end or raised horizontally or equally at both ends. The
action of this arrangement of parts is as follows:-Suppose no current exists in the
circuit, the two solenoids will be inactive, and their cores or armatures will allow the
said clutching plate to assume a.horizontal position, as it will be resting upon a
stop or table provided for that purpose; the carbon holder will. therefore be free
to fall through the, said plate, and the carbons will thus be in contact. A current
is now sent, both solenoids become active, and the cores or armatures pull up the
plate, but the main circuit solenoid will be stronger than the shunt at first, therefore
the plate will be tilted slightly and raised in such tilted or angular position, thus
the carbon holder will be locked by and raised with the clutching plate, and the
arc will be established; now as the carbons consume, the shunt coil will gradually

page_text: become more powerful and the main coil will weaken, so that the plate will
gradually assume a horizontal position by the combined action of the two solenoids;
the carbon holder will then slip or drop a small distance and the arc will be
reduced, this however has the immediate effect of weakening the shunt solenoid or
coil and strengthening the main, so that the plate is immediately tilted and so grips
or jambs the holder, preventing further feed until the balance is again disturbed. Now
suppose the main current should be weakened by any external cause, such as more
lamps put in circuit or reduction of speed, in this case it will be seen that the
solenoids will become weaker, and the plate will therefore be depressed at both
extremities by both armatures, so that the carbons will be brought closer to each
other at once;
but be it well remarked, not by the slipping or feeding of the carbon
holder, but by the direct action of the two solenoids. Again, suppose the main
current is increased by, say, an increase of machine speed or lamps taken out of
circuit, in this case both solenoids would become stronger and the clutching plate
would therefore be lifted at both ends, and thus the carbon holder would be raised
with it and the arc at once increased in accordance with the stronger current, the
further feed of the carbons would then be regulated by the future mutual action of
the two solenoids as previously explained.
It will be seen that this arrangement of parts produces a similar result as the
first described plan when springs and clock work are used, which is the maintenance
of arcs according to the individual requirements of each lamp in a circuit, with this
very important addition, that the size of the arcs in the circuit also depend to a
very material extent upon the strength of the main current. As in the previously.
described plan various modifications of the mechanical parts in this second method
may be employed, therefore I do not limit myself to the precise mechanism
described, but the essential features are the arrangement of the two coils or
solenoids whereby a plate or lever is worked at both extremities by the armatures
of the said coils, the said plate or lever having two distinct movements, viz., an
angular or axial movement which locks and unlocks the carbon holder, and an up
and down movement "in toto" which carries the carbon holder directly up and
down with it; the said axial movement being produced by the opposite actions of
the solenoids, and the up and down movement by their similar actions. The plate
spoken of may be replaced by a sleeve fitting the holder loosely and having a cam or
pawl within it worked by the tilting lever and solenoids, this cam or pawl to lock
or unlock the holder according to the angle of the lever, as in the case of the
jambing plate before described.
It will be seen that by using the two solenoids, as above described, they do not
act in direct antagonism to each other, and that therefore the main solenoid may
be constructed of much less resistance than in lamps of the usual differential
principle.
I sometimes construct lamps regulating on the above principle, having three
magnets, two of these being in the main circuit, and one in the shunt; one of the
two main magnets I use to separate the carbons the requisite distance for the arc,
the other two magnets I use as previously described, viz., the second magnet in the
main circuit slackens or tightens the regulating or feeding spring against which
the shunt magnet or solenoid acts. Instead of having two magnets in the main.
circuit in combination with the shunt coils, as above cited, the main magnet may
actuate or influence two armatures, one armature being used to separate the carbons,
the other to slacen or tighten the feeding spring as before described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Brockie in the Great Seal Patent Office on the 4th November
1881.
JAMES BROCKIE, of Brixton, in the County of Surrey.
ELECTRIC ARC LAMPS."
"IMPROVEMENTS IN
This Invention refers to the particular construction and method of regulating
electric lamps, substantially as hereafter described, in order that they may operate
in a more perfect manner than hitherto, and also that when two or more lamps are
placed in the same circuit the arcs shall be regulated according to their individual
requirements, and at the same time, to a very important extent, according to the
strength of the current. For these purposes I employ two solenoids or magnets in
my improved lamps, one being placed in the main circuit, the other in a branch or
shunt across the arc. I am well aware that the employment of two such solenoids
in electric lamps is not new, but the relation to each other in which I place them,
the duties I impose upon them, and the mechanical combinations I operate by means
of them, according to this Invention, I consider novel and to constitute a radical
improvement in electric lamps.
The first method of carrying out this part of my Invention will be better
understood by describing how it may be applied or adapted to existing lamps of
well known construction. Take the lamp, for example, known as the "Serrin."
In this lamp the arc is first obtained by the direct action or pull of a magnet in
the main circuit, and the future regulation and feed of the carbons depends upon
the further action of this same magnet by its allowing the escape of a feeding train
of wheels as the current weakens by the consumption of the carbons. Now
according to my Invention I employ the second magnet or solenoid, which is in the
shunt bridging the arc, to release; retard, or stop the feeding train, but at the same
time the main magnet or solenoid plays an all important part in the action of the
said second or shunt magnet, videlicet, the tightening or slacking of the spring against
which the second solenoid acts, so that when a strong current exists in the main
circuit the main magnet, in addition to directly enlarging the arc (as in the "Serrin "
lamp), will pull or tighten the said spring, and when a weak current passes it will
slacken the said spring; in fact, the tension or strength of the feeding spring
against which the shunt magnet acts will depend upon, and be automatically
regulated by, the strength of the main current through the agency of the magnet
in the main circuit.. This feature constitutes the novel element in this part of my
Invention, the advantage of which when compared with existing methods, that is,
of using two such solenoids, will be seen; the said comparison will also shew more
clearly the action of my improved apparatus. Compare, for instance, the well
known "Siemens" (Alteneck), or the
Brush differential coil lamps, which work
with two solenoids, either in direct mechanical or magnetical antagonism. Suppose
such lamps are duly burning, the main current is now, say, weakened, by any cause,
as, for example, lamps being put in circuit, or change of speed, both solenoids will
be weakened equally, or practically so; therefore, as the solenoids counteract each
other, the position of the carbons will remain the same. Again, on the other hand,
should the main current be increased by any cause, both coils will strengthen
equally, but no change will take place in the position of the carbons, the feed or
regulation being permitted only when one solenoid or coil overpowers the other;
therefore the arcs in such lamps remain constant to a great extent, whether the main
current is strong or the reverse. Now by arranging the two solenoids or magnets
according to my Invention, as described and shewn at Figure 1 of the accompanying
Drawings, the improved action is as follows:-
"
"
Suppose the lamps are duly burning, the main current is now, say, diminished
by some such cause as before suggested, the main current solenoid A will therefore

page_text: by becoming weak reduce the tension of the feeding spring D, which will compensate
for the necessitated weakening of the shunt solenoid or magnet B, and at the same
time bring the lower carbon N a little closer to the upper carbon P, thus at once
reducing the size of the arc, and adjusting the feeding gear to the reduced strength
of the current. It will be seen that the core of the solenoid A is drawn. upwards
by the spiral spring C, the top half only of the said core being of iron, the lower
portion of brass or other non-magnetic metal, so that when the solenoid is active the
core is pulled downwards against the said spring, carrying the negative carbon
holder with it.
The shunt solenoid B actuates a brake K upon the upper holder H. The lever
of this brake plays between the 2 stops S1, S2, and has very little range of
movement. The lower stop forms an abutment, which allows the lower solenoid
core, as it moves up or down, to diminish or increase the tension of the feeding
spring D.
The piece T upon the main solenoid core is for the purpose of pressing up the
lever L when the lamp is extinguished, thus taking off the brake K, and therefore
allowing the top carbon holder H to descend until the carbons meet.
The carbon holder H is preferably retarded in its descent by a " dash pot," but
it will be readily understood that a train of wheels could be employed for this
purpose, in which case the brake K would be applied to the last wheel of such
train.
I sometimes construct lamps regulated on the above principle having 3 magnets
or solenoids, 2 of these being in the main circuit, and the third in the shunt across
the arc; Figure 2 shews this arrangement. One of the two main magnets A² I use
to separate the carbons the requisite distance for the arc. The othe two magnets
A and B I use as previously described with reference to Figure 1, namely, the
second magnet A in the main circuit slackens or tightens the regulating spring D,
against which the shunt solenoid or magnet B acts.
This plan has the advantage of putting all the heavy work of moving the lower
carbon holder upon one main magnet, whose action or play is preferably limited to
the length of the arc, and putting the more delicate work of the subsequent feeding
upon the other two magnets.
Instead of having two magnets in the main circuit in combination with the
shunt coil, as above described, the main magnet may actuate two armatures, one
being used to separate the carbons, the other to regulate the tension of the feeding
spring, as before described.
The second method of carrying out my Invention consists in employing the
two solenoids to operate directly upon one of the carbon holders by means of a
clutching device; Figure 3 shews the gearing of a lamp constructed on the above
principle.
The upper or positive carbon holder H is free to fall by its own weight, but is
preferably retarted in its descent by a "dash-pot or analogous device.
»
This clutching device, shewn in detail, Figure 4, consists of two pieces, the body
or main part M, which is bored out large enough to allow the holder H to pass
freely through it, and the hinged piece R which, when lifted upwards, jambs or
locks the holder H so that the holder may be lifted up with it; when on the other
hand the body M of the clutch is raised, while the hinged part is stationary, the
holder will slip through the clutch. The two solenoids A and B are arranged on
either side of the said carbon holder H, the clutch just described is operated upon
by the two solenoids at its two extremities, the main solenoid A engages or
lifts the front or hinged piece of clutch R, and the shunt coil operates upon the
body M.
The action of this arrangement is as follows:-
Suppose no current exists in the circuit, the two solenoids will be inactive, and
their cores or armatures will allow the said clutch to rest upon the bottom of the
lamp case or small table provided for it; the carbon holder will therefore be free to
slip through the said clutch, and the carbons will thus be in contact. A current is
#

page_text: now sent, both solenoids become active, but the main current solenoid A will be
stronger than the shunt at first, therefore the clutch will be lifted by its hinged
part at R, the main solenoid core or lifter thus locking the holder and carrying it
up with it; thus the arc will be established. Now as the carbons consume, the
shunt coil B will gradually become more powerful, and begin to lift the clutch
at its other extremity M, thus causing the clutch to relax its grip on the holder H,
and so allow it to slip downwards and the arc to be reduced; this however has
the immediate effect of weakening the shunt coil B, so that the end of the clutch
is instantly again depressed and so locks the holder, arresting the further feed until
the shunt coil again becomes more powerful. Now suppose the main current
should be weakened by any external cause, such as more lamps being put in circuit,
or reduction of speed, in this case both solenoids A and B would become weaker,
and the clutch would thus be allowed to fall slightly, and the carbons be brought
closer to each other at once; but, be it well remarked, not by the slipping or
feeding of the carbon holder through the clutch, but by the direct action of the
two solenoids. Again, suppose the main current is increased, in this case both
solenoids would become stronger, and the clutch would therefore be lifted by the
main solenoid at the hinged end, and the arc at once increased in accordance with
the stronger current.
The further feed of the carbons would then be regulated by the future action of
the two solenoids, as previously described.
It will be seen that the regulation of lamps constructed on this improved
principle is placed on a high or low basis according to the strength of the main
current by means of the main solenoid A, as this determines the height of the
clutch from the stationary table at the bottom of lamp, so that the core of the shunt
coil B has a longer or shorter distance to travel before it can release the grip of the
said clutch.
Although I have described a particular description of clutch, I do not limit
myself to the use of the said form, as nuínerous mechanical clutching devices could
be constructed and operated upon by the two solenoids in a manner substantially
the same as the one I have described.
Figures 5 and 6 shew other forms of clutch which could be employed; Figure 6
shews a simple plate with an opening in it just large enough to allow the holder to
slip through it. The main coil operates at one end of this plate R, the shunt coil
at the other end M, just in the same manner as before described. Figure 5 shews
another plan, where a sleeve M fitted with an eccentric cam R is operated on by
the two solenoids; the main solenoid raises the cam lever R, thus locking or
jambing the the holder in the sleeve M. The shunt coil B lifts the sleeve itself, thus
relaxing the grip of the cam. Indeed the form of clutch may be much varied, as
may be seen, without affecting the principle of this Invention.
1. sometimes construct lamps on this principle having two or more pairs of
carbons.
Figures 7 to 10 shew a lamp. having two pairs of carbons; both carbon holders
Hand H are lifted at the same time by the main solenoid A by means of the
rocking shaft K¹ and lifters Z, which engage the front part R of the clutches. The
other extremities M of the clutches are worked by the shunt solenoid B by the
other rocking shaft K2 and lifters T, T, but by means of a lever S, shewn in plan,
Figure 9, one of the carbon holders is prevented from falling as the said lever
enters a slot in the side of the carbon holder H2. This lever is operated by the
other carbon holder H' in such a manner that when the holder H¹ has arrived at
nearly its lowest position, the lever S is pushed away by an inclined plane J fixed
on the said holder, and thus the lever S is withdrawn from the slot in the second
holder H2; this allows the holder H2 to descend when permitted by the solenoids.
The other holder of course can descend no further, and the are then appears between
the other carbons just released.
Figure 11 shews in diagram an apparatus embodying the principle of my
Invention, which could be applied in many ways to regulate or control the

page_text: adjustment of the carbons in electric lamps, the lever L being employed, for
instance, to short circuit, cut out, or reverse the magnet operating the carbons, or
indeed in many ways controlling the feeding gear of electric lamps.
And having thus described the nature of this Invention I do not, as already
stated, claim any particular clutching device, but I claim,
First. In electric lamps the automatic adjustment of the feeding spring by the
action of a magnet in the main circuit, so that the tension of the said spring will
be determined by the strength of the main current.
Second. In electric lamps the employment of two solenoids or magnets, one being
placed in the main circuit, the other in a shunt across the arc in such a manner
that the main magnet separates the carbons the requisite distance for the arc, and
at the same time adjusts the tension of a spring, against which the shunt solenoid
acts, the said shunt solenoid being employed to control the feeding gear of the
lamp, so that by the above arrangement the tension of the feeding spring against
which the shunt solenoids pulls will be automatically adjusted by the main magnet,
according to the strength of the current, all substantially as described and illustrated
with reference to Figures 1, 2, and 11 of the accompanying Drawings.
Third. In electric lamps the employment of two solenoids or magnets, one being
placed in the main circuit, the other in a shunt across the arc, the main magnet
operating a clutching device, which lifts one of the carbon holders and thus produces
the arc, the shunt coil operating another portion of the said clutch, which causes
the clutch to relax its grip on the holder, and so permits it to descend, and thus
allow the carbons to approach, all substantially as described and illustrated with
reference to Figures 3, 4, 5, and 6 of the accompanying Drawings.
Fourth. The construction. of electric lamps regulating according to the above
principles, having two or more pairs of carbons, but only one pair at a time being
permitted to meet, the others being prevented by a stop from descending until the
said stop is released by the action of the carbon holder whose carbons have just been
consumed, substantially as described with reference to Figures 7, 8, 9, and 10 of
the accompanying Drawings.
In witness whereof, I, the said James Brockie, have hereunto set my hand
and seal, this Third day of November, in the year of our Lord One thousand
eight hundred and eighty-one.
JAMES BROCKIE. (LS.)