IMPRove- MENTS IN THE FEED REGULATING MECHANISM OF ELECTRIC ARC LAMPS
Year: 1885

page_text: We CHARLES FREDERICK COOKE of the Firm of T. Cooke and Sons Buckinghani
Works York and THOMAS ROBINSON 6 Queens Place Chapel-Allerton Leeds both
in the County of York do hereby declare the nature of our Invention for "IMPRove-
MENTS IN THE FEED REGULATING MECHANISM OF ELECTRIC ARC LAMPS" to be
as follows:-
This Invention is designed to make the Carbons in Electric Arc Lamps feed with
great regularity and certainty-It can be applied to any Lamp provided with a
Solenoid for striking the Arc and a train of wheels or worm wheel and worm
terminating in a brake wheel in such a manner that the Carbons cannot approach
without the above mentioned brake wheel rotating.
This Invention essentially consists of a specially sensitive method of liberating
the brake wheel of the Lamp and so allowing the Carbons to approach as soon
as the are grows appreciably longer than is normal In all lamps provided with a
solenoid for striking the arc and through which the whole current passes the
solenoid during the action of the lamp is strongly magnetized and attracts strongly
any iron Armature placed near it. In this Invention we make use of such an
Armature or tongue of iron placed in the best position near the solenoid of the
Lamp The iron armature and the brake which restrains the brake wheel form
practically one piece and the armature is pulled back from the solenoid and at
the same time the brake held off the brake wheel by a light spring or weight
When the current passes the solenoid is strongly magnetized strikes the arc and at
the same time pulls towards it the Armature and so causes the brake to press
on or detain the brake wheel and this continues until the arc growing too long
presents more and more resistance to the current until the latter passing through
the solenoid decreases sufficiently to liberate the armature and set free the escape-
ment thus allowing the Carbons to descend until the armature is again drawn back
towards the solenoid by the current recovering itself. In order to make the
decrease in the current still more marked and decided when the are grows too
long we make use of a shunt magnet coiled with fine wire through which a
small portion of the current always flows instead of through the arc thus when
the arc grows long not only does the current decrease in the manner described
.

page_text: above but in a twofold degree for the whole current passing through the Lamp
decreases in the first place and on the other hand the current passing through the
solenoid decreases in a further degree owing to a larger proportion of this already
decreased current passing through the shunt magnet-We place this shunt magnet
which may be the one used for cutting the Lamp out of circuit in case of
accident in such a position that one pole or both poles as the case may be are
tolerably close to and on that side of the iron tongue or armature opposite to the
Solenoid, that is, the Iron Armature lies between the Solenoid on the one side and
one or both poles of the shunt magnet on the other The solenoid and the shunt
magnet now act in concert for if the arc grows too long not merely does the
armature tend to spring back owing to the decreased power of the solenoid but
a large increase of power taking place simultaneously in the shunt magnet, the
latter further helps to pull the armature back from the solenoid thus liberating
the brake and allowing the Carbons to approach until the current through the
solenoid increases and the current through the shunt magnet decreases respectively
to its normal proportions when the brake is again caused to detain the brake
wheel-In the case of double or twin lamps we make use of one and the same
shunt magnet-which is placed so that its poles lie between and actuate the iron
tongues or armatures of both Lamps.

page_text: Improvements in the Feed Regulating Mechanism of Electric
Arc Lamps.
We CHARLES FREDERICK COOKE of the firm of T. Cooke and Sons, Buckingham
Works, York and THOMAS ROBINSON of 6 Queens Place, Chapel-Allerton, Leeds,
both in the County of York, 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 is designed to make the carbons in Electric Arc Lamps feed with
great regularity and certainty providing a sure and reliable means whereby any
slight increase of the resistance of the arc above the normal amount will imme-
diately lead to the restoration of the arc to its normal resistance thus ensuring
a practically steady light. It can be applied to any Arc Electric lamp provided
with a solenoid or solenoids for striking the are through which solenoid the whole
or nearly the whole of the current passes and with an escapement or train of
wheels or worm wheel and worm terminating in a break wheel in such a manner
that the carbons cannot approach one another without the said brake wheel
rotating.
In all lamps provided with a solenoid or solenoids for striking the arc and
through which the current or most of it passes the solenoid or solenoids during the
action of the lamp is or are strongly magnetized and attracts or attract strongly
any iron placed near it or them. In this Invention use is made of an armature or
tongue or armatures or tongues of iron placed near the solenoid or solenoids of the
Lamp, in the best position for the most effective action of the power of attraction.
The iron armature and the brake which restrains the brake wheel form practically
one piece and the armature is pulled back from the solenoid and at the same time
the brake held off the brake wheel by a light spring or weight. When the current
passes, the solenoid is strongly magnetized, strikes the arc and at the same time
pulls towards it the armature and so causes the brake to press on or detain the
brake wheel and this continues until the are growing too long presents more and
more resistance to the current passing through the solenoid until the current
decreases sufficiently to lessen the attractive force of the solenoid sufficiently to
liberate the armature and set free the escapement, thus allowing the Carbons to
descend until the armature is again drawn back towards the solenoid by the current
recovering itself. In order to make the decrease in the current still more marked
and decided when the arc grows too long a shunt magnet is employed, coiled
with fine wire, as a shunt past the arc, through which fine wire a small portion
of the current always flows instead of through the arc, thus when the arc grows
long not only does the current decrease in the manner described above, but in a
two fold degree, there is obtained the effect desired upon the armature, for the
whole current passing through the lamp decreases in the first place and on the other
hand the current passing through the solenoid decreases in a further degree owing
to a larger proportion of this already decreased current passing through the shunt
magnet and beyond this the tendency of the attraction of the shunt magnet is to

page_text: Figures 1 and 2 are elevations at right angles to each other of a twin lamp
provided with this Invention.
F, F, is the framework of the lamp and the are striking solenoid of each lamp is
shewn at S, S.
M is a fine wire shunt magnet arranged to carry a small fraction of the current
across the arc. It here does duty for two lamps, and may also be the shunt
magnet used for cutting the lamp out of circuit in case of accident. T T are light
tongues or armatures of soft iron fitted at their bottom ends loosely over the
spindles P, P. C, C, are arms permanently fixed to the spindles P and lying close
beside the armatures T T. The thumb screws Sc are passed freely through the
arms A carried by the armatures T, T, and are screwed into the arms C, C. The
springs Sp are fixed to the arms C, C, and their free ends press the arms A and
therefore the armatures T T back as far as the heads of the screws S, c, will allow.
Thus the armatures T T practically form part of the arms C, C, and therefore the
two move together. The small screws St below the screws Sc, are stop screws
stopping against the tails of the cock pieces F1 F1. At the other end of the
spindles P P are the brakes B B bearing upon the brake wheels W W. The
weighted arms C¹ forming part of the arms C, C, act as counterpoises, which by
their weight, keep the brakes B away from the wheels W, when there is no current
passing through the lamp, thus allowing the brake wheels W W to rotate freely
until the Carbons touch ready for forming an arc as soon as the current passes.
The stop screws St are adjusted to allow no more movement of the armatures T T
and the arms C, C, than is necessary to liberate the brake wheels W W. The
principle and action of the arrangement is as follows:-On either of the lamps
being started the solenoid S belonging thereto is strongly magnetized and strikes
the arc while at the same time the armature T, next to it is drawn towards the
said solenoid and presses the brake B on to the brake wheel W, which latter is
then prevented from rotating. A small fraction of the current is now passing
through the shunt magnet M. The carbons burn away and the resistance of the
arc to the passage of the current increases, thus causing a decrease of the current
passing through the solenoid and an increase of the current passing through the
shunt magnet M. Thus the pull exerted by the solenoid S upon the armature T,
is lessened, while the pull exerted by the pole of the magnet M upon the
armature T, is increased. When this process has gone far enough the two pulls

page_text: neutralize one another sufficiently to cause the armature T to be set at liberty to
fall back under the action of the weight C. On this taking place, the brake
wheel W is liberated and the carbons are allowed to approach until the current
passing through the solenoid S increases and the current passing through the
magnet M decreases to their normal amounts respectively, when the armature T
is drawn back towards the solenoid S, by the attraction thereof and the brake B
presses upon the wheel W sufficiently to detain it again.
It will be readily understood that when the other of the twin lamps is lighted,
the same effect takes place by the same action of the mechanism pertaining to that
lamp. It will be further readily understood that the mechanism of either of the
lamps can be similarly applied to single lamps.
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
First. In Electric arc lamps, the combination with, and for applying and
releasing the brake; of a soft iron tongue or armature, an arc striking solenoid,
carrying the direct current to the carbons, and a magnet wound with fine wire as
a shunt across the arc, all being arranged so that the said tongue or armature is
subject on the one side to the attractive force of the said arc striking solenoid and
on the other side to the attractive force of the fine wire shunt magnet.
Second. In Electric arc lamps the combination for the purpose described of a
tongue or armature, in proximity to the solenoid S the weighted arm C, C, spindle
or centre P brake B and brake wheel W, all arranged and combined together
substantially as hereinbefore described and illustrated by the accompanying
drawings.
Third. In electric arc lamps for the purpose described, the combination of a
tongue or armature in proximity to the solenoid S, the weighted arms C, C¹, the
spring Sp and adjusting screw or screws the spindle or centre P, brake B and
brake wheel W all arranged and combined together substantially as hereinbefore
described and illustrated by the accompanying drawings.
BO WA May of repruary 1000.
THOMAS VAVEY, J.P.,
Acting for and in the City of York.
CHARLES FREDERICK COOKE.
THOB ROBINSON.