Improvements in Electric Arc Lamps.
Year: 1895

page_text: Improvements in Electric Arc Lamps.
I, LOUIS BARRIÈRE, Mechanical Engineer, of 22 Rue Saint Sabin, Paris,
France, do hereby declare the nature of this invention to be as follows:-
The present invention relates to are lamps employed for electric lighting,
whether operating with a continuous or an alternate current.
It has for its object to provide an arc lamp the regulation of which is based upon
the novel application of a brake acting to arrest the motion of the carbons
towards each other, and operated by a movable core of a special construction, the
said core acting to light the lamp and to ensure the fixity of the arc during
operation, either with a continuous current or with an alternate current. Yet,
according to whether the energy supplied is in the form of a continuous current
or in the form of an alternate current, certain details of the lamp require to be
slightly modified, as will be explained hereinafter, in order to suit the lamp to the
nature of the current supplied.
In carrying out my invention in practice, I secure to the lower plate of the
lamp two coils of German silver, zinc or other suitable material; one of them
which acts for lighting the lamp is placed in the circuit of the said lamp and
carries a winding of stout wire, whilst the other, which acts. for regulating
purposes, is on a shunt from the same circuit and carries a winding of fine wire.
The upper portions of the central part of these coils are occupied by stationary
cores which are hollowed out or bored axially, whilst in the lower portions of the
said coils are movable cores.
:
The stationary coils for a continuous current lamp, whether it be the coil of
stout wire or the coil of fine wire, are formed of an ordinary soft-iron core bored
axially throughout. For alternate-current lamps, each of these cores is formed of
two concentric tubes of any suitable material, soldered at one end to a common
plug, the remaining free space between the tubes being filled by insulated wires of
soft steel.
The special arrangement of these bi-tubular cores having wires of soft steel for
alternate currents has for its purpose to greatly increase the sensitiveness of the
coils and to thereby insure more regularity in the action.
As regards the movable cores, their construction differs on the one hand
according to whether the core is intended for the coil of stout wire or for the coil
of fine wire, and on the other hand, according to whether the lamp is one for a
continuous current or one for an alternate current.
In a lamp for a continuous current, the core for the coil of stout wire is an
ordinary soft-iron core, whilst the core for the coil of fine wire is a soft-iron core
hollowed out or bored axially and into which is placed an adjustable spiral spring
connected at the upper end to the core and at its lower end to a regulating screw
passing through the lower plate of the lamp; the said spring constantly solicits
the movable core downward in opposition to the attractive action of the stationary
core.
In a lamp for an alternate current, the movable core of the coil of stout wire
is formed of a tube soldered at one end to a plug, at the center of which is screwed
a rod occupying the axis of the tube and extending the latter toward the top.
The space between the tube and the said rod is filled with insulated soft-steel wire

page_text: for the above mentioned purpose. Finally, the movable core of the coil of fine
wire in a lamp for an alternate current is formed of two concentric tubes soldered
to a common plug the space between the two tubes is filled with insulated soft-
steel wire and within the inner tube is an adjustable spiral spring which solicits
the movable core downwardly in opposition to the attractive action of the
stationary core.
The movable cores, whichever may be the arrangement thereof, are extended
upward axially, by means of a rod passing through the hole bored axially in the
stationary cores.
The rod of the coil of stout wire has on it an adjustable cap, the end of which
forms a fork into which is jointed the end of a two-armed lever pivotted to a
bearing fixed to the upper plate of the lamps. The other end of the said lever is
attached to the lower end of a spiral spring, the upper end of which is connected
to the upper plate of the lamp, and the purpose of which is to constantly solicit
the two-armed lever in such a manner as to tend the movable core to move down-
wardly. Between the point at which the spring is secured and the axis around
which the lever oscillates, the said lever carries an axis around which pivots a
grooved wheel; around the said wheel passes a rope one end of which carries one
carbon-holder, whilst the other end meets the other carbon-holder to which it is
attached after having made one full turn around a grooved pulley fastened in the
same plane as the first-mentioned pulley, upon a cross axis pivotted in suitable
brackets secured to the upper plate of the lamp. Upon the said cross axis is
secured a brake-drum around which is applied a brake-band; one ply of the said
band, which is narrower than the other, passes through a slot in the widest ply, at
such point where the plies meet. One end of the brake-band is adjustably secured
in a clamp fastened to the upper plate of the lamp, whilst the other end is fastened
in a clamp carried by an adjustable cap secured to the end of the rod forming an
extension of the coil of fine wire. The latter clamp carries furthermore an
adjustable contact screw having a platinum point, the end of which comes in contact
with a Z-shaped spring from which leads one of the ends of the fine wire winding
of the coil...
The said screw and Z-shaped spring thus perform the function of an automatic
current-breaker for the shunted winding of fine wire. The part played by such
breaker will be made apparent hereafter.
The carbon-holders are of the usual kind and the weight of the positive or
upper carbon-holder is much in excess over that of the negative or lower carbon-
holder.
Let it be assumed that no current is flowing through the lamp and that con-
sequently the movable cores of the coils are moved back to their lowermost
positions by the action of their springs and if it be also assumed that the brake is
on, the operation will be as follows: The carbons being apart from each other, the
current, when turned on, will flow through the shunt formed by the coil of fine
wire and will, energize the latter, whereby the movable core of such coil will be
instantly raised together with the clamp holding one end of the brake-band, thus
slackening the said brake-band; the brake-drum, the shaft thereof and the pulley
thereon being then free to rotate, the positive carbon-holder which is heavier than
the negative carbon-holder will move down and carry with it the negative carbon-
holder which is thereby raised and both carbons are made to move toward each
other. But during the said upward movement of the movable core, the contact
screw carried by the clamp on its rod has abandoned its Z-shaped contact spring,
the circuit of the shunted coil of fine wire is broken and as the said coil is no
longer excited, it allows its movable.core, to move down under the action of its
spring. The contact between the screw and the Z-shaped spring is then
re-established, the coil of, stout wire is again excited, the core moves upward, the
brake is off and so on, the same action being repeated successively, so that the
carbons are moved toward each other, in a rapid succession of small movements,
without any jerk. When the carbons touch, the current no longer flows through

page_text: .
the coil of fine wire, owing to the resistance of the latter and it then passes
entirely through the coil of stout wire which, as it is energized, acts upon its
movable core so as to move the same upwardly; the two-armed lever is thus
caused to oscillate around its axis in opposition to its spring and as the pulley
carried by the said lever is being moved downward, the negative carbon-holder is
allowed to drop by its own weight in order to separate the carbons until the
arc is formed. The lamp then takes its position of equilibrium and when by
reason of the consumption of the carbons, the resistance of the arc increases, and
the current flowing through the coil of stout wire decreases, the movable core
of the lamp is allowed to descend under the action of its spring, after which the
regulating operation of the lamp is effected by the coil of fine wire. As the.
resistance of the arc increases, the latter coil receives a stronger current and
causes its movable core to rise so as to bring the carbons closer together, as
hereinbefore explained.
For lamps of low intensity, and when it is desired to simplify the lamp and
also to avoid the necessity of making it too large for its intensity, the coil of
stout wire can be dispensed with together with the two-armed lever and the
pulley carried thereby. In such a case, I have recourse to a novel means of
lighting the lamp, the said means consisting in applying a milled knob or button
onto the extension of the axis of the brake-drum, such knob to be moved by hand
so as to separate the carbons and produce the arc.
F. WISE HOWORTH,
46,. Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
:..
I, LOUIS BARRIÈRE, of 22, Rue Saint Sabin, Paris, France, Mechanical.
Engineer, do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and-by the
following statement :-
-
This invention relates to arc-lamps employed for electric lighting, whether.
worked with a continuous current or with alternating currents.
Its object is to provide an arc lamp the regulating action of which is based on
the novel use of a band-brake which acts to arrest the advance of the carbons
towards each other and which is operated by a movable core which may be of
peculiar construction and whose action is to ensure the proper lighting of the lamp,.
and also the steadiness of the arc during working, either with a continuous current
or with an alternating current. According as a continuous current or an alternating
current is employed, certain details of the lamp, will, as hereinafter described, be.
slightly modified so as to conform to the particular requirements of the current at
disposal.
51.
~!!
În carrying my invention into practice, according to one arrangement I fix to the
lower plate of the lamp, two bobbins of German silver, zinc or other suitable
material, one of which is designed to serve for igniting the lamp, is inserted in the
lamp-circuit, and carries a winding of thick or coarse wire, whilst the other bobbin
is designed for the regulation of the lamp; is inserted in a shunt from the said
circuit, and is wound with fine wire. The upper parts of the central bores or
internal recesses of these bobbins, or solenoids are occupied by fixed cores which
are pierced or drilled along their axes, whilst in the lower parts of the bores of
the said bobbins there are movable cores which act through the medium of the
parts hereinafter described to ensure the igniting and the efficient working of
the lamp.

page_text: In a modification which is especially suitable for lamps with alternating currents
and which I prefer to employ therefor, I substitute for the bobbin wound with
coarse wire and its movable core, an electro-magnet composed of two bobbins
wound with coarse wire and a movable armature; and in place of the bobbin with
fine wire and its movable core, I employ an electro-magnet wound with fine wire
and a movable armature.
In order that my invention and the manner in which it is to be carried into
practice, may be properly understood I shall now proceed to describe the same in
detail with reference to the accompanying drawings.
Fig. 1 thereof is a front elevation of one construction of my improved lamp for
continuous or alternating currents, the stems of the carbon-holders being shown
broken off.
Fig. 2 is a detail view, in plan, of an insulated contact spring which is mounted
on the upper end of the fine wire bobbin and which will be described hereinafter.
Figs. 3 to 6. inclusive are detail-views, to which reference will hereinafter be
made, of the cores of the bobbins wound with coarse and fine wire respectively.
Fig. 7 is a detail-view of the ends of the brake-band.
Fig. 8 is an elevation of a modified form of lamp which I prefer to employ for
alternating currents and in which for the solenoids and their cores there are
substituted electro-magnets and movable armatures.
Fig. 9 shows the apparatus as seen in side view looking from right to left in
Fig. 8.
•
Fig. 10 is an elevation of a small portable arc-lamp of low power which is
suitable for offices and living rooms and with which ignition is effected by hand.
Figs. 11 and 12 are views corresponding to Figs. 8 and 9 respectively, of the
mechanism of the lamp shown in Fig. 10.
Reference being had first to the lamp shown in Figs. 1 to 7 inclusive, a a¹ are
the two plates of the lamp connected together by the pillars a² in the usual manner.
On the bottom plate a there are fixed two bobbins b, c (of German silver, zinc, or
other suitable material), one of which b, is included in the lamp-circuit and is
wound with coarse wire, whilst the other bobbin c is inserted in a shunt from the
said circuit, and is wound with fine wire. The upper parts of the central bores of
the said bobbins are occupied by fixed cores which are perforated or drilled along
their axes, whilst movable cores are adapted to move in the lower parts of the said
bobbins.
The arrangement of these fixed and movable cores varies according as the lamp
is worked with a continuous current or with alternating currents.
The fixed cores for continuous current lamps, both for bobbins wound with
coarse wire and for bobbins wound with fine wire, are composed of an ordinary
soft-iron core perforated or drilled from one end to the other along its axis.
For alternating-current lamps, each of the fixed cores, both for the coarse-wire
bobbins and for the fine-wire bobbins, is formed (see Fig. 3) of two concentric
tubes d d' of any suitable material, each soldered at one end to a common plug d²,
the vacant space left between the two tubes being filled with soft-steel wires
insulated from one another. The peculiar construction of these bi-tubular cores
lined or packed with soft-steel wire for alternating currents, has for its object to
increase to a considerable extent the sensitiveness of the bobbins and consequently
to ensure a greater regularity of working.
As regards the movable cores, their construction varies, first, according as the
core is designed for the coarse-wire bobbin or for the fine-wire bobbin c, and,
secondly, according as it is to be used in a continuous-current lamp or in an
alternating-current lamp.
The movable core of the coarse-wire bobbin for a continuous-current lamp is
composed of an ordinary soft-iron core; whilst for an alternating-current lamp,
the movable core of the coarse-wire bobbin, as shown in Fig. 4, comprises a tube e
soidered at one end to a plug e¹; the axis of this tube is occupied by a stem e?
which extends throughout its length and is screwed into the plug e¹. The space

page_text: left between the tube and this stem is filled with soft-steel wires insulated from one
another for the purpose above mentioned.
The movable core of the fine-wire bobbin for a continuous current lamp is
shown in Fig. 5. It comprises a soft-iron core f pierced or drilled along its axis
and containing an adjustable coiled spring connected at its upper end to the
core by means of a screw as shown. The lower end of the said spring is fastened
to an adjusting screw f' extending through the bottom plate a of the lamp. This
spring has a constant tendency to draw the movable core in a downward direction
in opposition to the attraction exerted by the fixed core.
The movable core for the fine-wire coil for alternating-current lamps comprises,
as shown in Fig. 6, two concentric tubes gg soldered to a common plug g², the
space between the two tubes being filled with soft-steel wires insulated from one
another. Inside the internal tube there is arranged an adjustable coiled spring
(not shown) the upper end of which is hooked to the flattened end of a rod i herein-
after described (see Figs. 1 and 6), which is screwed into a small plug g³.
soldered to the upper end of the inner tube g¹. The lower end of this
coiled spring.is connected to a screw-threaded rod similar to the rod f' shown.
in Fig. 5, and the said spring serves the same purpose as the spring /' of
that figure.
Each of the movable cores, of whatever construction it may be, is prolonged
upwardly along its axis by a rod or i (see Fig. 1) screwed into the upper part of
the movable core and extending through the hole drilled along the axis of the
fixed core.
The rod of the core of the coarse-wire bobbin 6 carries at its upper end an
adjustable cap h¹ whose end forms a fork 12 to and within which is pivoted one.
of the ends of a rocking beam ; fulcrummed at j¹ on a bracket fixed to the top
plate a of the lamp. The other end of the rocking beam ; is connected to the
lower end of a coiled spring the upper end of which is fixed at to the said top
plate a', and has for its object constantly to tend to pull the rocking beam in such
a manner as to move downwards the movable core screwed to he lower end
of the rod h. Between the point of attachment of its spring and its axis of
oscillation the rocking beam j carries an axle on which is mounted grooved
pulley over which passes a cord k one end of which carries the negative arbon-
holder, its other end being attached to the positive carbon-holder m after having
made one complete turn around a grooved pulley n keyed in the same velical
plane as the pulley je upon a transverse axle mounted to rotate upon two poin.ed
screws carried by a part n² of shape fixed to the top plate a' of the lamp.
Upon the axle of the pulley n there is fixed a brake drum o upon which is wound a
band of forming a brake, one portion of which is narrower than the other and passes
at the point of crossing of these portions, through a slot o² (see Fig. 7) formed in
the wider portion. One of the ends of the band o' is held in an adjustable manner
in a clip of fixed to the top plate a¹ of the lamp, and its other end is held in a
clip of carried by an adjustable cap of screwed on the upper end of the rod i, on the
lower end of which there is screwed the movable core of the fine-wire bobbin as
above described. The clip of carries also an adjustable contact-screw p provided
at its end with a platinum contact-point which comes into contact with a spring pl
of Z-form (shown in plan in Fig. 2), which carries on its upper limb a small
platinum plate upon which the platinum point of the screw p bears. This spring
is fixed on an insulating plate p³ (see Figs. 1 and 2; attached to the upper end c
of the fine-wire bobbin c. From this spring there proceeds one of the ends of the
fine-wire winding of the bobbin c.
The screw pand the spring p₁ thus act as au automatic current-interrupting
device for the fine-wire shunt-winding of the bobbin c as will be hereinafter more
particularly explained.
The carbon-holders and m are of ordinary construction, and the weight of the
upper or positive carbon-holder m is greater than that of the lower or negative
carbon-holder l.
j

page_text: The operation of the lamp is as follows :—
While no current is passing through the lamp, the movable cores of the
bobbins b and c are drawn into their lower positions by their springs;. .con-
sequently the brake is tightened, and the screw p is in contact with the
spring p¹.
The carbons..being apart, when current is passed through the lamp it flows
through the shunt formed by the fine-wire bobbin c and energizes this bobbin,
which has the result of causing the movable core of the said bobbin. to rises
and with it the clip 05, which as already stated grips one of the ends of the
brake-band o¹. The band o¹ being thus loosened, leaves the drum o and its axle
free to revolve under the action of the carbon-holder m, which, being heavier.
than the carbon-holder I, descends and moves with it the negative carbon-holder 1,.
causing it, through the medium of the cord k, to ascend and thereby making the
points of the carbons approach each other. But when on the aforesaid ascending
movement of the movable core and clip 0, the screw p leaves the spring p', the
circuit of the bobbin c is broken, and this bobbin, being no longer energized,
allows its movable core to descend under the action of its spring f. Contact is
then remade. between the screw p and the spring pl; the bobbin c is energized.
anew; the core reascends, the brake becomes again loosened; and so on, the same:
operations as above described being repeated in succession, in such a manner that
the carbons are moved towards each other by a succession of small steps or stages.
without suddenness or shocks.
As soon as the carbons come into contact, the current ceases to flow through the
shunt-bobbin c. on..account of the resistance offered by the said bobbin, and the
current then passes wholly through the coarse-wire bobbiu b, which, becoming.
energized, acts upon its movable core and causes it to ascend. This ascending,
movement of the movable core of the bobbin b causes the rocking beam to rock
on its pivot in the direction of the arrow 1 (Fig. 1) in opposition to the action
of the spring j³. In this movement the pulley je descends and therefore allows the
negative carbon-holder. to descend by its own weight until the arc is struck
between the points of the carbons.
The lamp now assumes its position of equilibrium, and when, in consequence of
the wearing away of the carbons, the resistance of the are increases, and therefore;
the flow of current in the coarse-wire bobbin b becomes reduced, this bobbin will
allow its core, to descend again under the action of the spring 3, after which the
regulation of the lamp is effected by the fine-wire bobbin c, which, in proportion as
the resistance of the arc increases, receives a stronger current, and causes its
movable core f¹ to rise and so to move the carbons closer together as above
described.
For alternating current lamps, I prefer, instead of the arrangement shown in
Fig. 1, to employ the modification shown in Figs. 8 and 9.
In this construction I dispense with the solenoids b and c, and I substitute for
them, electro-magnets whose movable armatures play the part of the movable cores
of the preceding arrangement.
...
With the exception of this substitution, the parts of my lamp are like, and are
indicated in Figs. 8 and 9 by the same letters of reference as those shown in Fig. L
It is therefore unnecessary to repeat the description of the same here.
In lieu of the bobbin b of Fig. 1 there is an electro-magnet composed of two
bobbins B B2 wound with coarse wire, and the bobbin c is replaced by an electro-
magnet whose two bobbins C1 and C2 are wound with fine wire. The bobbins. B¹
and B2 are in the lamp circuit, whilst the bobbins C1 and C2 are in a shunt from
that circuit.
1
For the purpose of facilitating tlie putting together of the lamp-mechanism,
instead of fixing the electro-magnets B1 B2 and CC2, like. the solenoids of the
arrangement herein before described upon the bottom plate a of the lamp, I support
thein by means of two cross pieces a³. and a fixed on the pillars or stay-rods a
This arrangement allows of the regulation, by means of two set screws, of

page_text: the height of the electro-magnets so as to ensure the proper working of the
apparatus.
The cores B and C³ of the electro-magnets are composed of pieces of soft-iron
wire insulated from one another, and are attached to the cross-pieces B and C+,
which are composed of small plates of thin soft sheet-iron insulated from one
another, preferably by means of varnish.
The movable armatures B and C (which take the places of the movable cores' of
the arrangement previously herein described are composed of insulated plates of
thin sheet-metal placed on edge. These armatures carry at their centres the
herein before described screw-threaded rods and i, which terminate respectively at
the rocking beam ; and at the lower end of the brake-band o¹.
The winding of the bobbins B₁ B and C C2 is effected two wires at a time.
These two wires may be arranged side by side or in two layers one above the other.
In this manner I obviate self-induction to a large extent and so considerably
diminish the extra-current on breaking circuit, when the shunt-circuit from.the
lamp.terminals is broken.
Similarly to the movable core f of the preceding arrangement shown in Fig. 1,
the armature C of the fine wire magnet C1 C2 is acted upon by an adjustable
spring designed to counterbalance the attractive tendency of the electro
magnet C¹ C²
The operation of the lamp shown in Figs. 8 and 9 is identical in every respect
(taking into consideration the substitution of the electro-magnets for the solenoids)
to that of the lamp shown in Fig. 1, so that it is unnecessary to repeat the
description. I may, however, state that in Figs. 8 and 9 I have indicated: in:
substitution for the guidance of the carbon-holders by means of: square stems, an
arrangement in which the stem of each carbon-holder is round and rolls between
two sets of three rollers g, one of each of which enters a slot or recess formed in
the stem of the carbon-holder for the purpose of keeping it in the proper path so
as to ensure the perfect alignment of the carbons.
t
For lamps of low intensity or power, with the object of simplifying the lamp and
of obviating the necessity of making it of dimensions too great in proportion to its
power, the coarse-wire bobbin 6 may be dispensed with, as also the rocking beam">
and the pulley je, in which case the lamp is ignited by hand adjustment.
(
In this arrangement (see Figs. 10, 11, and 12), I arrange the carbon-holders i
and m at the upper part of the lamp without altering in any way the regulating-i
mechanism, which, as in the arrangement shown in Fig. 1, is actuated by the
fine-wire bobbins c in a shunt from the lamp-circuit, and the parts of which are
indicated by the same letters of reference as in Fig. 1, the sole difference between
this mechanism and that of Fig. 1 is that the ignition of the lamp, instead of being;
automatic, is effected by hand by means of a knob or buttons mounted on the end'
of the axle t of the pulley. n, this axle being prolonged at the corresponding end so
that the knob or button is outside the lamp casing. The knobs may be insulated'
or not, according to the circumstances of the case.
It will be readily understood that in lamps located within reach, nothing is easier
than to operate the knob s in such a manner as to maintain the carbons slightly
apart from each other, until, their heating having become normal and the lamp.
having assumed its position of equilibrium, the lamp is properly ignited and the arc
continues to be produced by the action of the solenoid c and the brake hereinbefore
described.
In order that the lamp constructed.as described may be rendered portable and
that it may be easily moved about, I provide it with a special rheostat u composed
of two ferro-nickel wires.v, to wound in helical form, insulated from each other, and
enclosed in any suitable protective sheath or casing. At the end of the conducting.
cord or cable thus formed there is mounted a current contact-fitting adapted to be
placed in a fixed mount or in the socket of. an incandescence lamp as will be well:
understood.
*
It is obvious that though more particularly.. designed with the view of being.
t

page_text: applied to my improved arc-lamps, my arrangement for igniting the lamp by hand
may be equally well applied to arc-lamps of other kinds, by prolonging the axle of
the drum or pulley over which the cord passes that connects the carbon-holders.
It will also be understood that I do not limit myself to the exact details of
construction shown by way of example in the accompanying drawings, because
these details may be varied within wide limits without departing from the essential
nature of my invention.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. An arc-lamp for use with a continuous current or with alternating currents,
comprising a solenoid of coarse wire included in the lamp-circuit, and a solenoid of
fine wire included in a shunt between the terminals of the lamp, in combination
with fixed cores and movable cores arranged inside the said solenoids, the said
movable cores being energized, according to the manner in which the current passes
through the said solenoids, so as to operate respectively a rocking beam and a band
brake for the purpose of effecting the striking of the arc and of regulating the
distance between the carbons in order to ensure the steadiness of the arc produced,
substantially as described.
2. In an arc-lamp for a continuous current or for alternating currents, the
combination with a coarse-wire solenoid in the lamp-circuit, and a fine-wire solenoid
in a shunt between the said circuit, each of the said solenoids being provided with
a fixed core bored or drilled along its axis, and also with a movable core having an
adjustable spring; of two carbon-holders carried at the two ends of a cord making
a complete turn around a pulley keyed on the axle of a brake-drum, and a brake-
band making a turn around the said drum, and having one of its ends attached to a
fixed point of the lamp, and the other end connected to the upper end of the
movable core of the fine-wire solenoid, substantially as and for the purposes herein-
before set forth and as illustrated in the accompanying drawings.
3. In an arc-lamp for a continuous current or for alternating currents, the
combination, with a coarse-wire solenoid included in the lamp circuit, and a fine-
wire solenoid in a shunt from the said circuit, each of the said solenoids being
provided with a fixed core bored or drilled along its axis and with a movable core
having an adjustable retracting spring, of a lower negative carbon-holder, an upper
positive carbon-holder whose weight is greater than, so as to overcome, the weight
of the negative carbon-holder of a brake-drum mounted on an axle pivoted in a
suitable bracket fixed to the top plate of the lamp, a brake-band making a turn
around the said drum and being fixed at one end to a clip attached to the said top
plate and at its other end to the movable core of the fine-wire solenoid, a rocking
beam pivoted in a bracket attached to the said top plate, the said rocking beam
being jointed at one end to a rod connected to the movable core of the coarse-wire
solenoid and being connected at its other end to one end of a spring which is fixed
at its other end to the top plate of the lamp, a pulley rotatably mounted on the
rocking beam at a point between the centre of oscillation thereof and the point of
attachment of its spring, a pulley keyed on the axle of the said brake drum, and a
cord passing over the said pulleys and making a complete turn around the last
mentioned pulley, the whole substantially as and for the purposes hereinbefore set
forth and as illustrated in the accompanying drawings.
4. In an arc-lamp for a continuous current or for alternating currents, the
combination with a fine-wire solenoid in a shunt from the lamp-circuit, of a fixed
core located within the said solenoid, a movable core recessed or bored out along
its axis and located in the solenoid below the said fixed core and adapted to be
attracted by the latter when the solenoid is energized by the passage of a current
therethrough, an adjustable spring attached at one end to the lower end of the said
movable core and at its other end to the bottom plate of the lamp, a stem forming
an upward prolongation of the movable core and extending through the hole bored

page_text: in the fixed core, a cap located on the said stem and carrying a contact screw, and
a contact-spring co-operating with the said screw and mounted upon an insulating
plate fixed at the top of the solenoid, the said screw and spring forming an
automatic device for interrupting the shunt circuit, substantially as and for the
purpose described, and as illustrated in the accompanying drawings.
5. In an arc-lamp for alternating currents, the combination, with a coarse-wire
solenoid included in the lamp-circuit, and a fine-wire solenoid in a shunt from the
said circuit, of a fixed core located within each of the said solenoids and composed
of two concentric tubes connected at one end to a common plug, the space left
between the two tubes being filled with soft-steel wires insulated from one another,
substantially as and for the purposes herein before described.
6. In an arc-lamp for a continuous current, the combination with a fine-wire
solenoid arranged in a shunt from the lamp-circuit and provided with a fixed core,
of a movable core consisting of a soft-iron core which is bored or drilled along its
axis and in which there is situated an adjustable coiled spring one end of which is
connected to the said movable core and the other end is attached in an adjustable
manner to the bottom plate of the lamp, substantially as and for the purposes
hereinbefore described.
7. In an arc-lamp for alternating currents, the combination with a coarse-wire
solenoid arranged in the lamp-circuit and provided with a fixed core, of a movable
core composed of a tube connected at one end to a plug in the centre of which
there is screwed a rod situated in the axis of the tube, the space left between the
tube and the said rod being filled with soft-steel wires insulated from one another,
substantially as and for the purposes herein before described.
8. In an arc-lamp for alternating currents, the combination with a fine-wire
solenoid arranged in a shunt from the lamp-circuit and provided with a fixed core,
of a movable core composed of two concentric tubes connected to a common plug,
the space between the two tubes being filled with soft-steel wires insulated from
one another, and an adjustable spring arranged inside the inner tube, and having
one of its ends attached to the said movable core, and its other end attached in an
adjustable manner to the bottom plate of the lamp, substantially as and for the
purposes herein before set forth.
9. In an arc-lamp for alternating currents, the combination with the carbon
holders and the means controlled by a band-brake for supporting them in positive
connection with each other, substantially as described, of an electro-magnet having
two bobbins wound with coarse wire arranged in the lamp-circuit, and an armature
connected to a rod which acts, when the electro-magnet is energized, upon the
parts serving to move the carbons apart, an electro-magnet having two bobbins
wound with fine wire arranged in a shunt from the lamp-circuit, and an armature
which is arranged to be drawn back by an adjustable spring in opposition to the
attractive action of the last-mentioned electro-magnet and to which is fastened a
rod that is connected to the brake-band and acts to release the same, when the last-
mentioned electro-magnet is energized by the passage of a shunt current through
its windings, so as to cause the carbons to move nearer to each other, and an
automatic interrupting device actuated by the movement of the armature of the
shunt electro-magnet for the purpose of making and breaking the circuit of the
said shunt electromagnet, substantially as and for the purposes herein before set
forth and as illustrated by the accompanying drawings.
10. The improved arc-lamps constructed, arranged and operating as hereinbefore
described with reference respectively to and shown in Figs. 1 to 7 inclusive, and in
Figs. 8 & 9 of the accompanying drawings.
11. A portable arc-lamp for a continuous current or for alternating currents,
comprising two carbon-holders connected together by a cord which passes once
around a pulley, a brake-drum keyed on the axle of the said pulley, a brake-band
which passes once around the said drum and one end of which is attached to the
top plate of the lamp, a fine-wire solenoid arranged in a shunt from the lamp-
circuit and having a fixed core and a movable core, the latter core being connected
B

page_text: to the other end of the said brake-band and acting when it is operated by its sole-
noid, to release the said brake-drum and to allow the carbons to move nearer
together, in combination with an interrupting device that is carried by the rod or
stem of the said movable core and acts when operating, to make and break the
circuit of the said solenoid so as to produce a gradual approach towards each other
of the carbons, and a button or krob such as s, fixed on the axle or spindle of the
aforesaid pulley and brake-drum for enabling the lighting up to be effected by
hand by moving the carbons away from each other, and a rheostat such as u, v, w,
substantially as and for the purposes hereinbefore described and as illustrated in
Figs. 10, 11, and 12 of the accompanying drawings.
.Dated this 21st day of October 1895.
F. WISE HOWORTH,
r
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.