Improvements in Electric Arc-lamps.
Year: 1893

page_text: Date of Application, 5th Aug., 1893
Complete Specification Left, 6th June, 1894-Accepted, 4th Aug., 1894
:
Improvements in Electric Arc-lamps.
A communication from A. BUREAU, of 4, Boulevard Jamar, Brussels, in the
Kingdom of Belgium, Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention to be as
follows:
The lamp consists of a plate supporting two columns which are connected
together by a yoke and serve in guiding the two carbon holders which latter are
connected together by any suitable means such as a cord passing over a grooved
pulley.
The improvements embrace a movable lever supporting the shaft of the grooved
pulley. The shaft carries also a toothed wheel gearing with a train of toothed
wheels so as to drive another wheel provided with escapement teeth normally
engaged by a fixed detent. The lever is adapted to oscillate and is provided at
one extremity with a bar of soft iron which is arranged in proximity of the two
poles of an electro-magnet with very fine windings; the other extremity is
connected to a spring tending to remove the soft iron armature from the electro
magnet.
The operation of the lamp is as follows: The carbons, when in their normal
position, are not in contact. The current circulating through the conductor acts
on the magnet and attracts the armature thereby causing the lever to oscillate and
disengage the escapement wheel from the detent whereupon the toothed wheels
begin to turn and bring the carbons together. At the next moment the lever
moves up again and the escapement wheel engages with the detent, the carbons are
separated again and the same cycle is repeated.
Through the consumption of the carbons the resistance of the arc is increased
upon which a small proportion of the current is diverted and caused to act
slightly on the lever disengaging the wheel from the detent so that the carbons can
only approach each other very little at a time and the whole cycle of movements
becomes continuous with a normal consumption of the carbons. The up and down
movement of the lever is limited in one direction by a rigid stop at the pole end of
the electro magnet and in the other direction by a stop at the end where the spring
is connected to it. The sensitiveness of the movement is regulated according to
the tension of the current in the lamp by means of a spring fixed to the lever and
to a screwed rod adapted to be tightened by means of a nut.
The upper carbon holder is insulated from its carrier and adapted to slide on the
columns but the lower carbon holder is in electrical contact with a crosshead which
latter slides on one of the columns while at the other end it is connected with an
internal guide tube inside the second column. The connection between the cross
head and the internal guide tube is very simple, the extremity of the cross head
being bent at right angles so as to fit exactly into the tube.
Binding screws one of which is insulated from the plate while the other is
electrically connected with it are adapted to conduct the current in the usual
manner.
In order to insure a perfect contact for the lower carbon holder the latter is
directly connected with the body of the lamp by means of a flexible conductor
fixed to one of the supporting columns.
The lever is provided with a metallic cord for the purpose of facilitating the
inspection of the lamp for replacing the carbons, for cleaning or regulating the

page_text: escapement &c. when it is only required to hook. the eye of the cord to a pin on
one of the columns in order to lower the lever and disengage the escapement wheeli
from the detent.
The lamp can be suspended by means of a simple iron wire hooked on to two.
pins or screws at the extremities of the supporting plate and provided with a
small grooved pulley or roller of wood in the centre so as to insure perfect.
insulation.
The improved lamp presents a great advantage in the very simple construction
and combination of the parts as well as in the extensive use to which it can
be easily adapted as it works just as well with high as with low tension
currents.
All the parts are of a simple form and easy to manufacture, the dimensions are
adapted so as to insure regular operation while at the same time preventing
excessive wear of the moving parts.
Dated this 9th day of August 1893.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
A communication from ANTOINE JOSEPH BUREAU, of 4, Boulevard Jamar,
Brussels, in the Kingdom of Belgium, Engineer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex
Chartered Patent Agent, 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 electric arc-lamps and will be best understood by
reference to the accompanying drawings in which
Figure 1 is a general elevation of the lamp the parts which are not distinguishing
characteristics of the invention being omitted.
Figure 2 is an end elevation partly in section.
Figure 3 is a plan of the working mechanism of the lamp.
Figure 4 is a diagram of the circuits.
Figures 5 and 6 show some details of the carbon-carrier.
The lamp consists of a plate supporting two columns B which at the lower end
are connected together by a yoke not shown in the drawings and serve in guiding
the two carbon holders which also are not shown. These latter are connected
together by any suitable means such as a cord H passing over a grooved
pulley N.
The improvements embrace a movable forked lever or frame L supporting the
shaft O of the grooved pulley N. The shaft O carries also a spur-wheel M which,
through the wheels P, Q and S, also mounted in the frame L rotates the wheel U
whose rim is provided with a suitable frictional surface. The frame L is pivotted
so that it may oscillate in a vertical direction arranged to move horizontally to and
fro, carrying with it the shaft O of the pulley N near one of its ends and it is
provided at one extremity with a bark of soft iron which is arranged in proximity to
the two poles K K' of an electro-magnet or shunt-coil with very fine windings i, i¹ i²;
the other extremity is connected to a spring 6 tending to remove the soft irou
armature h from the poles K K' of the electro-magnet.
The operation of the lamp is as follows;-
The carbons, when in their normal position, are not in contact. The current
circulating through the conductor acts on the shunt-coil and the magnetic
poles K K' attract the armature thereby causing the frame L to oscillate so that

page_text: its right end in Figure 1 is depressed and disengages the detent-wheel U from the
brake V whereupon the toothed wheels begin to turn and bring the carbons
together. At the next moment the shunt-current loses power, the frame L moves
up again and the detent wheel U engages with the brake V, the carbons are
separated again, and the same cycle is repeated.
Through the consumption of the carbons the resistance of the arc is increased upon
which a small proportion of the current is diverted and caused through KK'
to act slightly on the armature h and frame L disengaging the wheel U from the
brake V so that the carbons can only approach each other very little at a time
and the whole cycle of movements becomes continuous with a normal consumption
of the carbons.
The improvements comprise further a brake-device or commutator which
completes and breaks a secondary shunt circuit which is obtained by dividing one
of the two coils of the electro-magnet as shown at (Figures 1, 3 and 4) on
the accompanying drawings. The purpose of this arrangement is to add a higher
resistance at the moment when the shunt derivation comes into action, which has
the effect of at once weakening the derived current. This arrangement of brake
and contact V is jointed at VI, the point where the conductors terminate, which
lead from the half-coils while the friction wheel U is in contact with the body
or mass of the upper plate. The working of this regulating device is as follows;-
When the current is passed through the lamp, the carbons are removed from each
other; the shunt current (terminal 1 P P half-coil P³, P, jointed brake V: V, P*
upper plate, and terminal (see diagram Figure 4) causes the descent of the
frame L. The regulating screw V2 (Figure 1) allows the impact of the brake,
against the insulating piece V' fixed on the support or upright V* to be regulated;
and thereby the release of the brake V from the wheel U and the cessation of the
friction can be adjusted at will. When V' comes in contact with V³, the brake V
is prevented from accompanying any further the descent of the friction wheel U
and from that moment the train-gear commences to act; but at the same time the
circuit V, P, ¹ is broken so that the current must traverse the second half-coil.
The resistance of the circuit is thereby augmented, the current is weakened, the
frame L ascends again bringing the friction wheel U once more into contact with
the brake V, which arrests the motion of the train gear; but simultaneously the
circuit is closed by the renewal of the contact, cutting out the second half-coil,
and the whole cycle recommences.
This arrangement of brake and contact consequently acts as a constant
compensator for the consumption of the carbons by checking the intermittent
release of the frame L, which thus results in an absolutely regular and unintermittent
wearing of the points, however irregular the currents may be.
The up and down movement of the frame L is limited in one direction by a rigid
stop g at the pole end of the electro-magnets i and in the other direction by a
stop c at the end where the spring b is connected to it. The sensitiveness of the
movement is regulated according to the tension of the current in the lamp by means
of the spring b connected at its upper end to the frame L at a and at its lower end
to a screwed rod fadapted to be tightened by means of a nut e.
The upper carbon-holder is insulated from its carrier and adapted to slide on the
columns B but the lower carbon-holder is in electrical contact with a cross-head
which slides on one of the columns B while at the other end it is connected with
the second column. These carbon-holders, not being new, and offering no special
feature, are not illustrated in the drawings annexed.
Terminals or binding screws, one of which is insulated from the plate A while
the other is electrically connected with it, are adapted to conduct the current in
the usual manner.
In order to ensure a perfect contact for the lower carbon-holder, the latter is
directly connected with the body of the lamp by means of a flexible conductor
fixed to one of the supporting columns B.
Figures 5 and 6 show the method of fixing the lower carbon in its holder, by
:

page_text: means of an iron sheet W acting as a spring upon the carbon, and admitting of
removal by pressing a finger upon the movable end W', another finger being at the
same time pressed against the arm y. The pins X X serve as supports to the
carbon on the opposite side to that which is pressed against the iron sheet W.
The frame L is provided with a metallic cord for the purpose of facilitating the
inspection of the lamp for replacing the carbons for cleaning or regulating the
escapement &c.
When it is only required to hook the eye of the cord to a pin on
one of the columns B in order to keep the frame in the lowered position and
disengage the friction-wheel U from the brake V so as to set the train-gear free.
The lamp can be suspended by means of a simple iron wire in the form of a bow
hooked on to two pins or screws at the extremities of the supporting plate and
provided with a small grooved pulley or roller of wood in the centre so as to
ensure perfect insulation.
The connection between the shunt coils, terminals, and leads, the course of the
current through the body of the lamp and carbon points, and also the shunt circuit,
are easily to be seen and understood by the aid of the figures in the accompanying
drawings.
The improved lamp presents a great advantage in the very simple construction and
combination of the parts as well as in the extensive use to which it can be easily
adapted as it works just as well with high as with low tension currents, two electro-
magnetic forces, acting like two antagonistic springs, to balance the masses and to
compensate and regulate the movements.
All the parts are of a simple form and easy to manufacture, the dimensions are
adapted so as to ensure regular operation while at the same time preventing
excessive wear of or collision between the moving parts.
Having now particularly described and ascertained the nature of the said
invention, as communicated to me by my foreign correspondent, and in what manner
the same is to be performed, I declare that what I claim is ;-
1. In an electric arc-lamp the arrangement of a pivotted frame such as L
carrying the spindle of the pulley-train operating the carbon by cord chain or rack
the said spindle commanding a reducing train-gear and a friction-wheel U whereon
a jointed contact device such as V V₁ exerts a brake-action to keep the carbons
stationary whenever the oscillating frame L is raised by the action of an antagonistic
spring weight or other force and is disengaged therefrom whenever the said frame
is lowered by the attraction of the poles an induction coil the said jointed contact-
device being designed to compensate by the interpolation of a higher resistance in
the shunt circuit at the moment that the carbons begin to move towards each other
for the magnetic force acting upon the oscillating fork and thus to obtain a finer
and more exact regulation of the movement of the carbons substantially as described
and illustrated in the accompanying drawings.
2. In an electric arc-lamp the arrangement of electro-magnets with shunt
coils derived from the main circuit of the lamp in such manner that when the
carbons consume away and the resistance of the arc augments a part of the current
is shunted acts slightly upon an oscillating frame brings about the disengagement
of the friction wheel sets the carbon-train in motion and causes the carbon points
to come together substantially as described and illustrated in the accompanying
drawings.
3. In an electric arc-lamp the arrangement of fixed stops at the two extremities
of the frame to limit the extent of its oscillations whereof the sensibility depends
upon the intensity of the current by an antagonistic force attached to the said
Oscillating frame and to a screwed spindle or rod adapted to be adjusted by means
of a hand-nut substantially as described and illustrated in the accompanying
drawings.
4. The combination and arrangement of all the different parts whether merely
constructive or working parts and more particularly of the oscillating frame with
soft-iron armature the electro-magnet with shunt coils the plate with its columns or

page_text: guide tubes and suspensory device the whole substantially as described and as-
illustrated in the accompanying drawings.
5. The arrangement bereinbefore described and diagrammatically represented in.
Figure 4 of the accompanying drawings whereby the lighting is effected by the
shunt action securing the separation of the carbons substantially as described.
6. A carbon-holder characterized by a plate such as W in the form of a spring
acting upon the carbon and capable of being displaced by the pressure of one
finger upon the movable extremity W₁ and another against a fixed arm such as y
substantially as described and illustrated in the accompanying drawings.
Dated this 6th day of June 1894.
W. P. THOMPSON & BOULT,
Agents for the Applicant.