IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1881

page_text: LETTERS PATENT to Bristow Hunt, of Serle Street, Lincoln's Inn, in the
"
County of Middlesex, Gentleman, for an Invention of IMPROVEMENTS IN
ELECTRIC LAMPS." A communication from abroad by Alexander Ephraim
Brown, of Cleveland, Ohio, in the United States of America.
COMPLETE SPECIFICATION filed by the said Bristow Hunt at the Office
of the Commissioners of Patents on the 17th September 1881.
BRISTOW HUNT, of Serle Street, Lincoln's Inn, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN ELECTRIC LAMPS." A communication from abroad
by Alexander Ephraim Brown, of Cleveland, Ohio, in the United States. of
America.
This Invention relates to that kind of electric lamps in which the light is
produced by the "voltaic arc," and known as the "are" type of lamp, and has for
its object a better regulation of the movement or movements of one or both of the
carbons (as the case may be) to ensure the maintenance of the carbon points con-
tinually in the proper relative positions to produce a perfect equality of resistance
during the time of their consumption, and thus ensure a perfect steadiness of the
light.
It has long been sought to provide for use in connection with the kind of lamp
I have alluded to some practical means for so feeding either one or both of the
carbon points (according to whether the lamp be one in which only one, or a lamp
in which both carbons move), or for so regulating the motion of the carbon (or
carbons) of the lamp as to ensure a perfectly steady light; and numerous con-
trivances have been devised (and many patented) for this purpose.
The most successful form of regulator practically which is known is that kind
used in what is known in the market as the "Brush" light, and which consists
essentially in a sort of friction-clutch through which the rod or tube of the carbon-
holder noves, and which is caused at the proper times to grasp or engage with the
said rod or tube, and (moving it to the proper extent and in the right direction) to
effect the proper separation of the carbon points and ensure their retention just far
enough apart to produce the desired result.

page_text: But in lamps supplied with this kind of regulator the light is more or less
unsteady, and frequently its unsteadiness is very perceptible, rendering the use of
such lamps for some purposes very unsatisfactory and undesirable.
It is proposed by this Invention to overcome this great difficulty in the use for
many purposes of this type of electric lamp, and to this end the Invention consists
in the hereinafter described novel means for regulating the feed of the carbon
point (or of both where both move), whereby a perfectly steady and uniform light
can be produced.
To enable those skilled in the art to which this Invention appertains to more
fully understand and to practice the same, I will proceed to more fully explain it,
referring by letters to the accompanying Sheets of Drawings, and in which I have
illustrated an electric lamp of the "are" type, having the improved regulator
applied thereto.
Figure 1 is an elevation; and Figure 2, a vertical central cross section of an
electric lamp embodying the Invention, in a form in which it has been practically
tested with perfectly satisfactory results.
Figure 3 is a perspective view of a portion of the feeding device, shown in
Figure 2, (viz., the plunger, valves, and rods) removed from the tubular carbon-
holder. The plunger is here drawn as if a section of it were cut out, in order to
more clearly show the arrangement of the parts and the inside construction.
Figures 4 and 5 are sectional views showing slight modifications of the improved
regulator, but Figure 5 is more complete than any of the others shown in the
details of the actuating mechanism of the feeding device, and is best arranged for
general practical use.
Figure 6 is a sectional view showing other modifications of the Invention.
In the several Figures, the same parts wherever they occur will be found
designated by the same letter of reference.
A and B are respectively the positive and negative carbon pencils, one of which
(the lamp not being a focussing lamp) is permanently located in the proper position,
and the other of which is suitably suspended or arranged immediately over the
first named in the usual and well understood manner of arranging such carbon
pencils, or as they are sometimes called "carbon-points."
The framework C of the apparatus, as shown, is about the usual form, and D, E,
are the binder posts to which are respectively connected the positive and negative
ends of the wires through which the electric current is supplied, the current-when-
the carbons are properly adjusted passing through them, and creating at their
slightly separated points the voltaic arc and electric light upon the well understood
principle of operation of this kind of electric lamps.
F and F are two helices of fine insulated wire of considerable length, suitably
arranged as shown, and through which passes a "shunt" current.
Pivoted to the lamp frame at a is a lever G, from one end of which depends (by
a link joint attachment b) a bar H, from which latter hang two soft iron cores I, J,
which as seen are thus suspended respectively within the helices F¹, F, so as to be
affected by any axial magnetism that may be developed in the said helices, for a
purpose and in a manner to be presently explained.
The other end of lever G may be provided with an adjustable counter-balancing
weight as at K, and between this end of the said lever and the point of its pivotal
connection with the lamp frame the said lever has attached to it by a pivot ca
bifurcated lever L, in the forked end of which is hung by a pivotal attachment a
pitman or rod d, to the lower end of which is attached a valvular plunger e that
works within a larger plunger f arranged within the tubular portion M of the
movable carbon-holder M, N.
The plunger is made to so fit the bore of tube M that when placed therein and
the latter supplied with some suitable lubricating material, preferably glycerine,
the said plunger may be with considerable exertion moved within the bore of the
said tube, and the said plunger f is so made with certain ports or passages i in it
that by virtue of the said passages and a proper movement or adjustment of the

page_text: valvular plunger e to open and close them communication between the space
above and that below plunger ƒ (in tube M) may be created and cut off to either
permit an easy and quick movement of plunger fin tube M, or to render any such
movement necessarily difficult and slow, as and for the purpose to be presently
explained.
The valve e is made tapering at its lower end, in order that by its movements
past the ports in plunger fit may more gradually open and close them, and the
said valve c is by preference connected to the lower end of a rod d by means of a
ball and socket joint, so that neither the rod nor the valve may possibly be cramped
in their movements.
For the purposes of a perfect adjustment of the valve e vertically in relation to
the plunger f within which it works, the valve rod d is provided at g with a screw
coupler joint.
The plunger f is suspended from the yoke like portion of lever L by two pitmans
or rods h, h, which have their lower ends connected to the said plunger, preferably
by ball and socket couplings.
The lever L is provided, as seen at %, with a light spring, the function of which
is to ensure the descent of the valve e whenever it may have been lifted, and the
said lever has at l an adjustable nut designed to come in contact with the adjust-
able inclined stop at m for the purpose of vibrating the said lever on its fulcrum
in a manner and to produce the effect to be presently explained.
The operation of the apparatus or machine so far described as to its construction,
more particularly that part constituting the means for feeding and regulating the
movable carbon, may be thus explained.
Assuming the parts to be in the condition in which they would be during the
disuse of the lamp, and supposing the connection to be made between the binder
posts and any suitable source of electricity, and then the carbons be separated (by
hand in this case) a short distance, the current passes through the posts, frame, and
carbons in the usual manner, and the shunt current passing through the helices F¹
and F causes the axial magnetisms developed to draw downward the cores I, J, to
a certain extent.
This movement of the armature or bar H vibrates the lever G in a manner to
make it lift the plunger f suspended therefrom, which in turn lifts the
tubular carbon-holder M, N, thus further separating the upper from the (in this
case stationary) lower carbon-point, and causing the required length of voltaic are
to be established.
But as the parts of the machine make these motions, induced by the motive
action of the said belices on said cores, the single (or free) end of the smaller lever L
has its nut thereby brought into contact with the stop m; the said lever is turned
on its fulcrum so that its forked end ascends lifting the valvular plunger e, the effect
of which is to so open the ports of plunger f that the latter readily moves within
its tube M, and the result of this condition of the apparatus is that the carbon
holder M, N, is allowed to descend to compensate for the consumption of the carbon
points in the production of the light, which of course tends to increase the distance
which originally existed between said points.
But this feed of the upper carbon downward operates to establish immediately
the proper degree of separation of the carbon, and the minimum degree of resistance
to the current in the development of the proper arc, and thereby the energy of the
"shunt" current and the axial magnetism of the helices F', F, are so correspondingly
decreased that the cores and armature H are allowed to slightly ascend, whereby
the lever L is partially relieved from the operation of the stop m, the result of
which is that the valve e is forced to reassume its former relation to the plunger f
closing or nearly closing the ports of the latter, and the said plunger f thus prevents
any further ready descent of the tubular carbon holder M, N.
In the above condition of the several parts, the plunger f at all times however
permits a very slow descent of the tubular carbon-holder, and it is only because
this descent does not quite compensate for the destruction of the carbons (and the

page_text: "
distance between their points therefore increases beyond the proper space) that the
resistance to the main current becomes increased, and the energy of the "shunt
current thereby increased, to effect such a condition of the parts as above described
as will permit a more rapid descent of the tubular holder M, N.
Now it will be seen that in a regulating apparatus or contrivance involving the
described principle of operation, viz., a mode of operation such that the moving or
movable carbon has a constant feed (in this case by gravity) but of a slightly
insufficient velocity, and the means for alternately augmenting the velocity of the
feed (or in other words, for releasing the feed from the influence of the means
which ensure the slowness of its motion) and restoring it to its normal condition,
derives its positive power by reason of the variation of the resistance to the
development of the voltaic are at the carbon points, the regulation of the feed of
the carbon point (or of the distance between the points) must necessarily reach
that degree of perfection which will ensure a practically steady or still electric
light.
And it will of course be understood that this principle of operation of the
improved regulator may be embodied in a machine differing as to the regulator
device shown, both in detail structure and in the combinations of the devices
herein shown and described.
At Figure 4 of the Drawings is shown, for instance, a modification in which the
detail construction of the main and valvular "plungers are considerably changed,
and where a single regulator helix is employed with the core that is operated by it,
arranged to work within a cylinder partially filled with fluid to retard its descent
by the magnetic action of the helix.
Figure 5 is another modification of the plunger and valvular feeding device
operated by actuating mechanism more complete in detail than shown in any of
the other Figures. In this Figure the regulator also differs from the others
described in the application of its actuating mechanism to the carbon feeding
device.
In the before mentioned regulators (Figures 1 and 4) the shunt current
helices F, F, so act in connection with the plungers fand valves c of the feeding
device, as to cause a partial separation of the carbons as well as a feeding motion.
of the same, while in Figure 5 the plunger f is acted upon through the power of
one or more helices in the main current F", causing from the start the separation
-of-the-carbons-and-the-establishment-of-the-electric arc of desired length, while the
shunt current core F governs and operates only the valve e or the feeding of the
carbons, or the maintaining of the are at a constant resistance after its first
establishment by the main circuit helix action as first stated.
In Figure 5 the lever G is connected to the armature l' at b, and pivoted at a to
the frame standard of C, and suspends from a point between these last by the rods h
the plunger f, which in turns suspends the tubular carbon holder M, N, when the
valve e is closed.
The dash-pot P, K, in pivotal connection with the extended end of the lever G,
serves the double purpose of dash-pot and counter-balance to the armature and
cores H, 1'. The adjustable stop T determines the extent of motion of the lever G
and its connected parts. The valve e is suspended from the lever L by rod d;
lever L is pivoted to the armature end of lever G at c, the other end of this lever
being connected to the armature I or core of the shunt helix F, about coincident or
concentric with the pivot a of the lever G. The core or armature 1 of shunt helix F
may be made as shown to serve also as its own dash-pot P governing its motions.
The core I and lever H may be counterbalanced to any desired extent by the
spring u. The screw m¹ serves to adjust the relative positions of the levers G
and L.
From the above it will be seen that in the operation of the lamp the valve e
remains unchanged in its relative position to the plunger f until it is acted upon
by the shunt helix F; that is, the two levers G and L act together as one lever
GL, pivoted to the standard at a and vibrated or moved by the armature (H, 1'),

page_text: when the helix For the main current alone acts to move them, and the shunt
current helix has not sufficient current through it to cause the armature or core (I)
to lift the lever (L).
Now since any increase of current in the main helices (F") that is due to any
diminished resistance in the electric are tends to decrease proportionately the
current in the shunt helix (F), and vice versa, it is evident that in the normal
working of this lamp the main and shunt helix levers G and L, and likewise the
plunger (f) and valve (e), will assume and maintain such relative positions to each
other as will allow of such a rate of feed of the carbon holder or carbons as will
just compensate for the burning away of the latter, and thus maintain the voltaic
arc at a practicably constant resistance and therefore produce a perfectly steady
electric light.
Of course by the proper changes within the mere mechanical judgment of the
skilled constructor this Invention may be applied in cases where it is desired to
have both carbons move for maintaining a given focus to the light (as, for instance,
in lights used with the lenses); and in practicing this Invention the main current
by a proper modification in the machine may be utilized in lieu of a "shunt"
current to operate the regulator devices by reason of the increased or diminished
magnetism of a helix, according to an increased or diminished resistance to the
passage of the current at the point where the voltaic-arc-light is developed.
These two modifications of the Invention are fully shown at Fig. 6, which
illustrates a focussing lamp, and one in which the carbon feeding and regulating
device is operated by the main circuit helix alone.
The maintaining of the light or are in one place or at a focus is accomplished by
having the motion of the upper carbon communicated to the lower or negative
carbon by means of the racks and gear wheels shown, the larger gear being pro-
portioned to the smaller one according to the rates at which the positive and
negative carbons are respectively consumed which is usually about in the pro-
portion of two to one, that is to say, as the upper carbon feeds down its rack turns
the larger wheel which being fast on the same shaft with the smaller one turns
the latter, on the opposite side of which engages the rack of the lower carbon-
holder, which in turn raises the lower carbon one half as much as the upper one
descends, thus the arc remains in a fixed locality.
The current enters one end of the helix and leaves the other through the flexible
conductor connected to the upper carbon-holder, passes from positive to negative
carbon and holder to binding-post and through the flexible conductor shown in
connection with the lower carbon-rack. The upper carbon-feeding-device tube is
guided by the encasing tube in which it freely moves and which forms a support
for the helix, as shown.
The movable core of soft iron or the armature of the helix is directly connected
to the plunger connecting rod, the adjustable nut on the rod and the pin from the
lamp frame (shown, limiting the motions of the core and hence those of the sinall
plunger. The small plunger works inside of the second plunger, which is
stationary in position and suspended from the lamp frame by rods, as shown.
The two small ports shown in the stationary hollow plunger are almost entirely
closed in that position of the smaller or movable plunger shown in the Drawings.
When the core of the helix is not acted upon by the current, the nut on the rod
rests on the lamp frame, and the small plunger is then so low in the large one as
to leave the ports open, and thus leave the rack or carbon holder tube free to fall
until the carbons come in contact, in which position they always are when there is
no current passing through the helix or the lamp is not in use.
It will be seen that when the lamp is started the armature or core lifts or raises
and together with it the small plunger connected to it; this plunger in lifting
passes over the ports and closes them, when its further motion is utilized in lifting
(by suction as it were) the upper carbon tube or holder, its rack in turn acting on
the wheels to move down (to half the extent of the upper carbon) the lower carbon;
thus the arc is established. Now as the carbons burn away the resistance to the

page_text: current increases, and consequently the magnetism of the helix diminishes, and
hence the core or armature will fall until the small plunger passes to a sufficient
extent the ports in the enclosing plunger to allow the carbons to feed to make up
for the burning, and as they do feed the magnetism increases again and the ports
are again closed to the proper extent. From this it will be seen that the core
will take just such a position as will make the feeding of the carbons as they burn
maintain an arc of constant resistance.
The extent of motion of the core being of necessity greater than the desired
motion of the upper carbon, I make the plunger that moves the carbons of 1-2, or
1-3, or 1-4, so that when it lifts, say, a distance of one the tube and hence the
carbon will only move 1-2, or 1-3, or 1-4, as the case may require.
Thus it will be seen a large range of change in the current will be allowed
without affecting except in a very small degree the voltaic arc.
It will be readily seen from the Drawing at Figure 6 what are the intended uses
and effects of all the parts.
The rods supporting the back end of the reflector shown serve also as guides
for the lower carbon-holder and rack, and to support one end of the bracket that
carries the spur wheels. The upper carbon holder is of course insulated from the
feeding tube to which it is screwed, as shown.
I therefore wish to have it understood that the claim of this Invention is not
limited to any of the precise details of the parts shown, or even to the particular
combinations of devices shown, as other combinations of devices of different detail
structure may be employed to compose a regulator contrivance or machine
involving precisely or substantially the same principle of operation and Invention
which I have described as being peculiar to and as constituting the novelty of the
contrivance herein described and shown.
Having now described the nature and object of the said Invention, together
with the manner in which the same is to be or may be perforined or carried into
practical effect, would remark in conclusion that I claim as the Invention com-
municated to me by the above named Alexander Ephraim Brown,-
a
First. The novel and peculiar combination with either or both of the carbons or
carbon-holders of an electric lamp of the are type of a mechanism for effecting
constant but insufficient feed of one or both carbons, and for alternately increasing-
the rate of speed-of-the-feed-and-allowing it to return to its normal rate of speed
in exact accordance with any increase or decrease in the resistance to the current
at the point of development of the light, substantially as herein-before described
and set forth.
And, Second. In an electric light regulator an electrode or carbon feeding device,
consisting of one or more tubes containing a suitable liquid, in which are one or
more plungers, valves, and ports, so constructed and situated in respect to each
other, and in combination with the actuating. mechanism and the electrodes or
carbons of the regulator, that the combined action of the parts affects the feeding
of one or more of the carbons by the opening of one or more of the said valves or
ports, and conversely restrains the feeding of the said carbons by the closing of
the valves or ports, all substantially as herein before described or set forth, and as
shown on the accompanying Sheets of Drawings.
In witness whereof, I, the said Bristow Hunt, have hereunto set my hand
and seal, this Seventeenth day of September, in the year of our Lord One
thousand eight hundred and eighty-one.