IMPROVEMENTS IN ELECTRIC LAMPS OR LIGHTING APPARATUS
Year: 1882

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LETTERS PATENT to. William Robert Lake of the Firm of Haseltine Lake
& Co. Patent Agents, Southampton Buildings, London, for an Invention of
IMPROVEMENTS IN ELECTRIC LAMPS OR LIGHTING APPARATUS" A commu-
nication from abroad by James John Wood, of Brooklyn, New York, United
States of America,
COMPLETE SPECIFICATION filed by the said William Robert Lake at
the Office of the Commissioners of Patents on the 31st May 1882.
WILLIAM ROBERT LAKE, of the Firm of Haseltine Lake & Co Patent Agents
Southampton Buildings London "IMPROVEMENTS IN ELECTRIC LAMPS OR
LIGHTING APPARATUS." A communication from abroad by James John Wood
of Brooklyn New York United States of America
The present Invention relates to that class of arc-lamps known as "double or
duplex" lamps, which are provided with two or more sets of carbons and corre-
sponding holders, the second set of which is thrown into luminous action as soon
as the first set is exhausted, whereby the light of the lamp is continued, without
interruption or attendance, over a longer period.
The object of the present improvements is to provide a simple and efficient
apparatus of this character which will embody two or more sets of carbons in such
a way that one set only will be in action at one time, and the strain of one only
will be borne by the regulating mechanism and its magnets or other motor, so that
such mechanism and motor shall have only the same work to perform as it has in
an ordinary single lamp, and will require no increased dimensions, power or
consumption of current, as is the case with duplex-lamps, heretofore produced, in
which the strain of both carbons is constantly borne by the magnet and both are
moved at the same time, one slightly in advance of the other.
In my lamp, both carbon holders are constantly engaged with the regulating
mechanism, but one is in "idle" engagement, and the other in active engagement, the
weight of the one which holds the second carbon, being supported by a latch, while

page_text: the weight of the active and leading one is borne by the regulating mechanism
which acts upon it in the ordinary manner till it is consumed, when its terminal
movement will trip the latch holding the second holder and allow the latter to fall
into active engagement with the regulating mechanism so smoothly that the light
is continued by the second set of carbons without break or interruption.
Now this Invention consists partly in the above partially described organization,
but more particularly in the peculiar manner of operatively connecting the two
sets of carbon-holders with the regulating motor or mechanism of the lamp namely:-
by means of a common driving device or spindle to which each of carbon holders
is engaged by clutches which bite in one direction and slip in the other direction
and have moreover, a limited play on the driving device in the direction of their
engagement; therefore whichever carbon holder is in active engagement with the
mechanism, so that its weight is borne thereby, such mechanism imparts all the
necessary regulating movements thereto without moving or affecting the idly
engaged holder of whose weight the mechanism is relieved.
The said Invention is illustrated in the Drawings in which:-
Figure 1 is a front elevation of my improved duplex-lamp, as the lamp appears
ready for use. The head or frame containing the mechanism is covered by its
cylindrical case, which conceals and protects the mechanism.
Figure 2 is a side elevation of the head or mechanism frame with the case
removed to clearly expose the mechanism.
Figure 3 is a vertical section on the line xx Figure 2 looking in the direction of
the arrows; and,
Figure 4 is a sectional plan on the lines o o Figure 2.
Figures 5, 6 and 7 show on an enlarged scale my improved duplex clutch
mechanism.
Figure 1 is drawn to a smaller scale and Figures 5, 6, 7 to a larger scale than
the other Figures.
The lamp in which I have shown my present Invention embodied, is as may be
observed, of a well known type, in which the motive power consists on the one
hand, in the attraction of the magnets in the circuit of the lamp, and on the other
hand, the weight of the carbon holders. The lamp is also of that type in which
the armature lever of the magnets carries a train of wheel, the leading pinion
gearing with rack-teeth on the carbon holder, while the terminal spindle of the
train is provided with an escapement, and with a detent or scape-wheel; these
parts are so arranged that, when the magnetic attraction preponderates, the wheel-
train and carbon holder, are raised, and the detent-wheel forced against a stop-
tooth which holds the train and prevents the descent of the carbon holder, but,
when the attraction is weakened and allows the armature lever to retract slightly,
the detent is withdrawn and the wheel-train released to allow the carbon holder
to descend; it is again stopped by the swaying of the armature lever and the
detention of the train when the carbon has fed sufficiently, as will be understood.
I prefer this type of mechanism, yet my improvement is not confined thereto,
and may be used with any suitable form of motor or regulating mechanism.
The lamp herein shown, is with the exception of my present improvements,
substantially identical with the apparatus forming the subject of another appli-
cation for Letters Patent filed by me this thirty-first day of May 1882 No. 2563,
and as shewn in the Drawings thereof.
The mechanism is included between two fixed circular heads a a¹ joined rigidly
by the standards b b and rod b¹, the whole being enclosed and protected when in
use by a removable cylindrical case c.
On the upper head a is fixed the binding posts to which the circuit wires connect
as shown and from the lower head a', arms all extend, and connect with pendant
rods & which are fixed at their lower end to the cross-bar e thus forming the harp
of the lamp in which the carbons appear, and which supports the globe and shade
that encloses them.
The said globe and shade are not shown, but the former is supported in the

page_text: circular depressed centre of the cross bar e and the latter is suspended by a pendant
loop:
From the centre of the cross-bar e arises a double holder g in which the two
lower or negative carbons are clamped, as shown, while the upper or positive
carbons hang in line therewith from the upper regulated holders h h¹. These
holders have the usual form of a long rod or tube, and pass through the mechanism
frame engaging with the mechanism therein; they are enclosed at their upper
ends by long tubes h h which are screwed into the upper head a and move &
cap or tip . This tip is formed with two sockets which fit the top of the tubes
and are fixed thereon by set-screws, and it has a central loop or eye j by which the
whole lamp may be conveniently suspended, and which forms at the same time a
neat symmetrical finish to the structure.
The carbon holders h h' are placed at a convenient distance apart as shown, and
as will be seen in Figures 2 and 3, are placed centrally in the lamp; or rather on
its diametric line equidistant on either side of the centre; on one side of them are
arranged the motor magnets k k¹ of the lamp.
These magnets are of the kind now generally employed, that is to say, they
consist of two pairs of coils or solenoids, or axial magnets, one pair ke being fixed to
the lower head a¹ and the other pair ¹ being fixed to the upper head, the two facing
each other with a double armature or core of an H-form, arranged to play
between them. This H-formed core is connected by trunnions at its neutral centre
or cross-piece to the armature lever m, which lever, as shown best in Figure 4, has
the form of a light open frame of a T-shape, placed in a horizontal plane and with
its stem passing between the standards b b and pivoted near the end of the stem
on the trunnion screws m¹, which work through the standards, and are held by jam-
nuts as shewn.
The open head of this T-shaped lever-frame encloses the said armature or core,
as seen in Figures 2 and 4, in which it is trunnioned at a point above its centre of
gravity, so that the core tends to bang vertically in the tube of the solenoids.
In the open panel on the stem of the T-shaped lever is arranged the frame n
which carries the wheel train as shown; this frame is pivoted to the lever on the
screws n', near its outer end at the lower and outer corner of the wheel-frame, as
clearly shewn in Figures 2 and 4.
The leading spindle o of this wheel train, is provided with pinions o¹ o" which
gear with the rack-teeth on the respective carbon holders h¹ h', as seen best in
Figure 4 and on the middle part of the spindle is fixed the large or leading toothed
wheel f' which gears with the succeeding pinion of the train, while on the terminal
spindle of the train are fixed the detent-wheel p and the escapement wheel p'
engaged by the vibrating fly escapement p" which acts the part of a pendulum to
prevent the too rapid motion of the train when released.
A spring r is fixed at its inner end to a projection extending down from the
upper head a, and at its outer end is securely clamped to the upper and outer
corner of the gear-frame n, so that this spring causes the frame and its train of
wheels to move up or down in a straight line with the carbon holder when the
armature lever is swayed one way or the other, as will be understood.
Now referring to Figure 2, the lower magnets k of the lamp, are of low resistance
and situated in the direct arc circuit, while the upper magnets k₁ are of high
resistance and situated in a shunt, and these resistances are so proportioned to each
other that when the separation of the carbon points is normal, the attraction of the
upper magnet k¹ and the pull of the adjustable tension springs (which act together,
but antagonistically_to the larger magnet k) will be just sufficient to keep the
armature lever in its medium position, as shown in Figure 2 in which position the
gear frame will be raised sufficiently to bring its detent-wheel p into contact with
a stop-tooth projecting from the spring thus holding the train, and thereby
keeping the carbon holder in suspension.
When, however, the carbons burn off so as to appreciably increase the length and
resistance of the arc, the upper or shunt magnet k¹ preponderates over the direct
ん

page_text: magnet k raising the core, swaying the lever m and causing the wheel frame n and
with it the carbon holder, to be depressed slightly so as to decrease the separation
of the points; if this depression is sufficient the detent-wheel will be withdrawn
from the stop-tooth r¹ thus allowing the train to escape and the carbon holder to
When the carbon holder has thus
descend to give the necessary feed at the arc.
descended sufficiently, the magnet k at once preponderates over both the magnet k¹
and the springs and in pulling down the core l sways the armature-lever in the
opposite direction, raises the gear train and brings the detent into contact with the
stop tooth thus stopping the train. When the train is thus stopped, the carbon
holder becomes positively engaged with the armature-lever, and if the current
strength in the circuit increases or decreases slightly, or if the resistance of the arc
increases or decreases slightly, the core l armature-lever m, and with them the wheel
train and carbon holder will bodily vibrate up or down slightly to correspondingly
regulate the arc without releasing the train, as will be readily understood.
It will now be seen, that the general mechanism of the lamp, so far as described,
is substantially of the ordinary type.
Now the location of my present improvements is mainly at and on the leading
spindle o of the wheel-train, which forms in effect the driving device or connection
between the motor magnets and the carbon-holders, and attention may now be
especially directed to this part which which is shown clearly in Figures 3 and 4,
and in enlarged detail in Figures 5, 6, and 7 This spindle, as will be observed, is
about twice as long as that used in a single carbon lamp, and is journalled at each
end in elbowed extensions on the wheel-frame n.
This
On the ends of the spindle are mounted the pinions o¹ o" which gear with the
respective carbon holders h h¹, the right-hand holder h (see Figures 1 and 3) being
the leading holder, which is shown near the end of its stroke with the carbons
nearly exhausted, while the left hand holder h¹ is the succeeding one controlling a
fresh pair of carbons, and shown at the top of its stroke and out of action.
holder is not only raised to the top of its stroke, but is there supported by a
latch levert on the underside of the upper head a', as shown in Figure 3, its long
arm being raised by a spring t¹ to hold its short arm in engagement with a tooth t
on the carbon-holder which is thus retained in suspension. It will hence be under-
stood, that, while the rack of each carbon-holder is always in engagement with its
pinion o' on oll yet the leading carbon-holder is in active engagement with its
pinion, and its weight is supported thereby, while the weight of the succeeding
holder h' is not on its pinion; and its engagement therewith is idle as will further
appear.
The pinions are engaged with the spindle by the ratchet device heretofore
employed, that is to say, the pinion o' is loose on the spindle but has a ratcheted
hub u which engages with pawls u' on a disc v which is keyed with the spindle,
so that the slip of the pawls and ratchets allows the carbon-holder to be raised to
any point without turning the train of wheels; (see Figures 2 and 6) yet these
ratchets and pawls engage in the opposite direction and keep the holder positively
engaged with the gearing in its downward direction.
In this lamp, therefore, the pinion of each carbon-holder engages with the
driving spindle in a well known manner, the ratchets of both having the same
direction, but a peculiar result follows from this duplex arrangement, as will now
appear.
The
Let it be supposed that the armature lever has been swayed so as to depress the
gear frame and release the train and allow the carbon holder to descend.
weight of the holder in thus descending will turn the pinion o¹ in a direction to
engage its ratchet with its pawl disc v and thereby turn the spindle o and the
entire wheel train, and through this spindle the opposite pawl-disc v¹ which is
keyed thereto will also turn therewith. But, as will be readily observed, this
pawl disc will turn around the ratchet of the opposite pinion o" in its direction of
slip, for the direction in which the driving ratchet u engages, is the same as that in
which the driven pawl-disc v¹ will slip, so that the second pinion o" remains

page_text: stationary in the rack of the stationary carbon-holder h¹ while the spindle turns
loosely in it.
Hence by this mode of engaging the two carbon-holders with the same driving
device through the intervention of clutches which bite in one direction and slip in
the other, and have the same direction of engagement, it follows, that if the strain
of one carbon-holder is borne by the mechanism at one clutch, and the strain of the
other is not borne by it at the other clutch, the one will be acted upon by the
mechanism, and perform all the necessary regulating movements in the ordinary
manner; yet these motions or actions will not re-act on the other holder; hence by
this very simple device, I provide a greatly improved duplex lamp in which the
magnets and mechanism act on one carbon holder at a time, and perform no
greater work and require no greater strength than is the case with the single
carbon lamp.
Now in addition to this feature of the duplex clutches, the said device contains
another peculiarity, different from the mechanism of the single lamp, that is to say,
the pawl discs vv instead of being keyed immovably to the spindle o are keyed
with a certain amount of play.
In Figures 4, 5 and 7 it will be seen that pins w w¹ are driven diametrically
through the spindle and engage with short slots or notches on each side of the
hubs of the pawl-dises, thus allowing a certain play between the spindle and the
discs.
I have hereinabove referred to the down or feed motion of the active carbon-
holder, and the rotation of the wheel-train under its impulse; and it will be seen
that these motions are not communicated to the idle carbon-holder. But in
addition to these motions there are the bodily vibrations up or down of the entire
wheel train, and with it the carbon-holder when the rotation of the train is stopped
by the detent wheel, which motions for "separation" and regulation must not be
communicated to the idle holder, any more than the rotary motion, In other words,
it will be readily understood, that when the wheel frame is raised sufficiently high
to catch the detent, the rotation of the train is stopped, and as the pinion o² can
hence not turn on the rack of the holder h the result is that the carbon-holder will
be raised by any further rise of the train.
Now as the idle holder h' is stationary, it follows, that when the wheel-train is
thus raised, the pinion o¹¹ must be free to roll on it in this upward direction, which
is the direction in which its ratchets engage, and this idle rolling is allowed by the
arrangement above mentioned, as will be readily understood by referring to
Figures 3 and 4. Thus it will be seen that the two pins ww¹ in the driving
spindle o will always be at relatively opposite sides of their play in the slotted
hubs of the pawl-discs v v¹ at the time when the rotation of the gear-train is
stopped by the rise of the same against the stop tooth; for the direction of the
rotating strain on the spindle is such that the pawl-disc vis the driver and the
disc is driven.
If the gear train continues to rise after its rotation is thus stopped, it will lift
the active carbon-holder h bodily with it, for all of the play of the leading pin w
is taken up, but during this upward bodily motion the opposite pinion oll will roll
idly in a backward direction on the rack of the stationary holder h' as the play in
the slot of its pawl-disc v¹ is just in that direction which allows of this backward
idle rolling being in the same direction as that in which the ratchets engage as will
be understood, thus preventing the bodily up or down motion of the train being
communicated to the stationary holder. This play therefore is proportionately
equal to the stroke of the armature-lever, and while it is always taken up at the
active clutch, it is always free at the idle clutch to allow the idle backward rolling
of the pinion o" on the stationary holder, as just described and well shown in
Figure 3. Hence by the constructions, described, neither is the rotary motion.
of the train, when impelled by the descent of the active holder, nor is the
bodily up and down motion of the train and the active holder transmitted to the
idle holder, which remains stationary, unaffected and unborne by the mechanism,

page_text: this result is a striking and valuable feature in my lamp and is accomplished by
very simple mechanism.
As soon as the carbons of the active and leading holder become nearly exhausted,
a projecting pin x on the upper end of the active carbon-holder approaches the end
of the latch-levert and, finally descending against the same, trips the latch and
allows the weight of the second or succeeding holder h¹ to fall into activé
engagement with its pinion o" while at the same instant a shoulder or flange on
the tip of the leading holder / becomes seated on the lamp-head a thus taking the
weight of the exhausted carbon-holder from the mechanism, and simultaneously
transferring the weight of the fresh succeeding holder h¹ thereto. At the same
instant the arc is formed between the fresh carbons, and the light is continued
thereby, without any perceptible break, for the transfer occurs with electrical
quickness, and almost before the arc ceases at the exhausted carbons it is established
at the fresh carbons.
When this change occurs, the second holder h' becomes the active one, and the
first holder his idle; but the action is precisely the same as already described, only
reversed as concerns the two holders; for the holder h¹ will now go through all the
usual regulating movements without at all affecting the now idle holder h as will
be readily understood.
It will hence be seen, that any successive number of holders might be arranged
in the same manner in one lamp or apparatus, and each would come into action
successively as the preceding one became exhausted, all those whose weight were
taken from the mechanism as described, whether exhausted or fresh ones, would
neither be acted upon by the mechanism nor react thereon.
I do not limit myself to the special details of parts illustrated in the Drawings,
as already intimated, for any suitable clutch other than the ratchet and pawl
whether frictional or positive may be used, and any suitable means for connecting
the duplex clutches with the driving mechanism of the lamp and with the carbons
or carbon-holders, may be employed in lieu of the rotary wheel-train and the rack
and pinions shown.
Another and minor novel feature of this lamp consists in the secondary spring y
additional to and in combination with the adjustable tension spring 8. Both of
these springs tend to pull down the carbon-holder in opposition to the main
separating magnet, and act in conjunction with the feed magnet k¹ and thus serve
to bring the carbons together so as to ensure the formation of the arc, the parts
being proportioned as follows:-When the lamp is quiescent with no current
flowing, the parts tend to assume the medium position shown in Figures 1 and 2
the armature lever being horizontal; in this position the weight of the core and of
the long arm of the armature-lever is just balanced by the weight of the short arm
and of the carbon-holder and that of the wheel train, together with the tension of
the secondary spiral spring y the gear train is thereby raised toward the stop
tooth but with hardly any pressure, so that if the carbons happen to be separated,
the slightest additional strain will cause the gear-frame to be depressed and
released, allowing the carbons to feed. This additional strain will be provided as
soon as the lamp is put in circuit by the current however weak, which will at once
circulate in the shunt magnet k and whose attraction will at once pull down the
gear-frame so as to release the saine and allow the carbons to come together to form
the arc, after which the main magnet k becomes energetic and moves the parts in
the opposite direction separating the carbons to form the arc, and lifting and
stopping the wheel train. Hence with the assistance of the spring y without the
springs the lamp is always fit for action, and this spring, y is designed to be
permanent and non-detachable, while the adjustable spring s is designed to be
detachable for the purpose of adjustment, so that in case this adjustable spring
should be left inadvertently detachable when the lamp is put in circuit, the lamp
will yet be fully operative.
The spring 8 is connected to its non-rotating adjusting screw 8¹ by means of an
inclined pin 8 which meshes with its spirals so that by detaching the hooked end

page_text: of the spring from its armature lever and turning the spring it will be screwed in
or out, and its active length thus increased or decreased so as to correspondingly
alter its elasticity, this adjustment together with the adjustment of its screw will
enable any desired tension to be put upon the spring.
Now this spring tension is provided mainly to affect the excessive strength of
the magnet and to adjust the action of the lamp to the strength of current
therein, and also to enable the length of arc to be regulated as required and made
uniform for a number of lamps in the same circuit, its function being thus distinct
from that of the permanent spring y which I term the "safety" or balancing
spring.
The direction of the current through the lamp is a follows that is to say.
Entering at the positive post on the head of the lamp, the current descends, through
the metal frame and through the upper carbon holder and carbon to the lower
carbon, and thence flows upward through the rod h, which is insulated from the
upper frame, but connects with the positive end of the coils of the main magnets k
(see Figures 1 and 3) so that the current thence continues through the magnets k
and flows off by the negative insulated post on the head a with which the negative
end of the coils connect, as seen in Figure 3.
The opposite ends of the coils of the magnet k¹ connect directly to the respective
binding posts, as shewn in Figure 3, being thus in a shunt as before stated.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent and the manner of performing the same I wish it understood
that I claim:-
First A duplex electric lamp constructed with a single motor or regulating
mechanism and two or more distinct sets of electrodes arranged to go into action
successively, and both engaged with the motor mechanism, but in such manner
that one only is borne and actuated thereby at the same time, together with a
device for taking the pressure of the succeeding electrode from the mechanism
while the leading electrode endures, and with another device whereby the terminal
motion of the leading electrode acts to remove its pressure from the mechanism
and at the same time transfers the pressure of the succeeding electrode thereto, all
substantially as and for the purpose herein set forth.
Second-A duplex electric arc-lamp, constructed with two or more distinct sets
of successively acting electrodes and a motor or regulating magnet in constant
circuit with the source supplying the arc, and having its actions determined by
the condition of the arc, with operative connections between the said motor magnet
and the duplex electrodes, so organized that one only is borne and actuated
thereby, and the other is relieved and unaffected, together with devices whereby the
terminal motion of the borne and leading electrode acts to remove its strain from
the motor magnet, and transfer the strain of the succeeding electrode thereto, all
substantially as and for the purpose, set forth.
Third A duplex electric lamp constructed with two or more distinct sets of
carbons or illuminating electrodes, and a common motor or operating device
connected with the said electrodes, or the holders thereof, by clutches arranged to
slip in one direction and bite in the other direction and so organized that, when
either electrode is borne by the operating device and the other not borne thereby,
the clutch of the former makes operative connection with the operating device to
control and regulate the motion of the active electrode without affecting the idle
electrode set substantially as herein set forth.
Fourth-A duplex electric lamp constructed with two or more sets of illuminating
electrodes, and a common motor or regulating mechanism, connected with the said
electrodes by clutches which slip in one direction and engage in the other direction
and have the same direction of action, and also a limited play in their connection
with the mechanism, and so arranged that both electrodes are engaged by the
mechanism, yet one is borne and actuated thereby, while the other remains unborne
and unaffected by the motion thereof, all substantially as herein set forth.
Fifth A duplex electric lamp constructed with two or more sets of electrodes

page_text: and a common motor or regulating mechanism equipped with a multiplying wheel
or train of wheels engaged at the terminal end by a detent or stop, and connected
at the initial end with the said duplex electrodes by the intervention of distinct
ratchet clutches or equivalent devices having the same direction of engagement, all
substantially as, and for the purpose set forth.
Sixth-An electric lamp embodying the following features, that is to say a motor
or regulating magnet, in constant circuit with the source supplying the arc and
having its actions determined by the condition of the said arc, with two or more
distinct sets of electrodes arranged to go into successive action as the preceding
ones become exhausted, in combination with a latch or catch to hold the succeeding
electrode out of action and relieve the motor mechanism from its pressure, and a
device whereby the preceding electrode at its terminal motion becomes itself
supported apart from the motor mechanism, and acts to trip the said catch to
release the succeeding electrode and throw its pressure on the motor mechanism,
together with connections, substantially such as is described, between the motor
mechanism and the electrodes, so organized that the said motor mechanism controls
the electrode, whose pressure is supported thereby, but does not act upon the one
that is relieved therefrom, all substantially as herein set forth.
Seventh-In an electric lamp the combination with a magnet in circuit with the
source supplying the lamp, and arranged to regulate the position of the carbons, and
with an adjustable retracting spring to antagonize the action of the magnet, of the
additional safety or balancing spring, substantially as, and for the purpose, set
forth.
:
Eighth In an electric lamp provided with two elongated carbon holders and
fixed enclosing tubes the tip i, formed with sockets secured to the tops of the said
tubes, and with a central suspending loop or bridge, substantially as herein set
forth, and for the purpose specified.
In witness whereof I the said William Robert Lake have hereunto set my
hand and seal this Thirty-first day of May in the year of our Lord One
thousand eight hundred and eighty two.