Year: 1886

page_text: Date of Application, 12th Apr., 1886.
Complete Left, 12th Jan., 1887.
Complete Accepted, 25th Mar., 1887.
We FRANÇOIS FESQUET, Engineer, of 42, Goodge Street, Tottenham Court Road,
London, and STANISLAS JULIEN, COMTE OSTROROG, of 5 Conduit Street London W.
do hereby declare the nature of this invention to be as follows :-
This apparatus is intended for the production of electric illumination by means of
an are lamp in which the feeding of the carbon points and the regulation of the length
of the voltaic are are effected automatically and in the most accurate manner by simple
and effective means and without the use of any spring whatever.
The feeding.and the regulating mechanisms are suspended one at each of the two
ends of a beam oscillating, scales like, round an edged center which rests on two
pillars mounted on the bed plate of the lamp.
The feeding mechanism is composed of the following pieces; the top carbon holder
which is terminated at the top by a rack; a pignon gearing with the said rack and
mounted on the axle of the wheel of a brake; and of the said brake, the wheel of
which is of a comparatively large diameter and provided with a ratchet wheel and
pawl; it is made of a strip of metal or any other material and encompasses the
circumference of its wheel. One of the ends of the brake is fixed and the other is
attached to the small arm of an oscillating lever bent at right angle and the long arm
of which is loaded with a counterpoise. The said counterpoise will cause the brake
to act and consequently prevent the top carbon descending as long as the long arm
of the bent lever is free from a fixed top screw placed in its vinicity; but on the said
long arm coming into contact with the said top screw, the weight of the long arm is
relieved, the bent lever oscillates and its small arm sclackens the brake, the wheel and
pinion of which are then free to turn under the action of the weight of the rack
carbon holder.
The regulating mechanism is composed of the soft iron cores suspended at the
end of the other arm of the beam the said arm being forked to receive them. One
of the said cores plunges into a thick wire solenoid through the coil of which the
circuit current is passing, and is adjusted so that the magnetic attraction of the
current is exerted upon it in a downward direction. The other core plunges into a

page_text: thin wire solenoid placed in shunt on the two terminals of the lamp and is so adjusted
that the magnetic attraction of the current is exerted upon it in an upward direction.
The weight of the feeding mechanism being greater than that of the regulating one,
when the lamp is not at work the brake's lever rests on the fixed top and the brake
being slack the top carbon touches the bottom one.
When the current is switched on the lamp, the greater portion of it passes through
the thick wire bobbin the downward magnetic attraction of which on its core over-
balance and lifts up the whole feeding system; the brake's lever parts from the top
screw and squeezes the brake so that the carbon holding rack is lifted up bodily with
the system and the arc is struck. The regulating and the feeding systems now
balance each other.
As the carbon points are wearing, the resistance of the arc increases, more current
passes through the fine wire bobbin and less through the thick wire one. The two
soft iron cores are now attracted in opposite directions and it is not before the upward
attraction of the fine wire solenoid upon its core has overcome the downward one of
the thick wire coil upon its core sufficiently for the long arm of the bent lever to come
into contact with the stop screw that the forked arm of the oscillating beam is released
and the feeding mechanism again overbalances the regulating one and the brake being
slackened the carbon-holder rack is allowed to descend.
The carbon points are thus brought nearer to each other and as soon as an excess
of current passes again through the thick coil the equilibrum is reinstated in favour
of the cores, the feeding system is lifted up and the brake is applied again.
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page_text: The arc is then struck; and, as the carbon points gradually wear out, the resistance
of the arc increases and less current passes through solenoid B and more through B¹.
The core or armature C of the latter being adjusted so as to counteract the effect of
the core C in solenoid B, that is to say acting in an opposite direction to core C,
when the balance of attractions is in favour of armature C₁ the beam oscillates round E,
the regulating system is depressed and lever L comes into contact with the stop K.
At this moment the brake H is released and the weight of the rack M together with
its carbon pencil causes its descent until the carbon points are again brought near
enough each other when, the calculated amount of current, passing again through
coil B, the latter's armature C pulls the beam down again with the result of raising
up the regulating system and applying the brake El upon the wheel F.
Should by any accident the top carbon slip and fall until it actually comes into
contact with the lower one, it will be seen that the are would immediately be struck
again whereas in many are lamps the arc cannot, in such emergencies, be re-established
before the carbon points have been consumed to a sufficient extent to create the
necessary gap.
Having now particularly described and ascertained the nature of our said Invention,
and in what manner the same is to be performed, we declare that what we claim is :
1° The arrangement of two compensating solenoids actuating, through their cores,
on which they act in opposite directions one arm of an oscillating beam, in one or
the other direction according to the amount of current prevailing in one or the other
solenoid substantially as hereinbefore described and illustrated.
2° The arrangement of a feeding mechanism suspended at the other end of the
aforesaid oscillating beam and consisting of a rack with its carbon holder, a pinion,
a wheel with a ratchet wheel and pawl, a brake which is released through the action
of a lever coming into contact with a fixed stop; the said feeding mechanism being,
when the lamp is at rest, heavier than the cores but when the lamp is burning in
normal conditions, nicely balanced with the cores and the attraction exerted upon them
by their solenoids, substantially as hereinbefore described and illustrated.
3° The arrangement for regulating the length of the are by means of a single stop
screw substantially as hereinbefore described and illustrated.
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