Improvements in and relating to Electric Arc Lamps.
Year: 1898

page_text: Improvements in and relating to Electric Arc Lamps.
We, LLEWELLYN BURBANK CODD, of 131, Belgrave Road, Edgbaston, Birming-
ham, in the County of Warwick, Electrical Engineer, and JoHN ALFRED CODD.
of The General Hospital, Wolverhampton, in the County of Stafford, Doctor of
Medicine, do hereby declare the nature of this invention to be as follows:-
-
Our invention relates to electric arc lamps and has for its object to provide a
simple and efficacious regulating device for striking and maintaining the requisite
length of the arc.
According to our invention we provide a brake drum or wheel having a peripheral
groove adapted to receive a chain, wire, or cord which is passed around the said
drum or wheel, and the ends of which are secured, adjustably or otherwise, to the
rocker-bar or lever carrying the cores or plungers of the coils or electro-magnets.
That end of the said chain, wire, or coil situated at the side of the rocker-bar or
lever carrying the core or plunger of the electromagnet or coil wound in shunt, is
attached at a point closer to the pivot or fulcrum of the said rocker-bar or lever
than the other extremity of the said chain or its equivalent.
The result of thus securing the ends of the brake chain, or its equivalent, at
different distances from the fulcrum or pivot of the rocker-bur or lever, is that
when the lamp is at rest the shunt side will be right down and the said brake chain
slack. Upon, however, the current being turned on, and the series coil or electro-
magnet becoming magnetized, its plunger or core will be pulled down so as to
likewise move in a similar direction that end of the rocker-bar or lever from which
it is suspended, and inasmuch as the brake chain, or its equivalent, is secured at
that side at a greater distance from the fulcrum or pivot of the rocker-bar or lever
than at the other, and is consequently forced to move through a larger arc, the
said brake-chain or its equivalent will be tightened upon the brake drum or wheel
so as to carry the wheel or drum around on its axis a sufficient distance and separate
the carbons the required distance.
Upon the arc becoming too long, the pull of the shunt coil or electro-magnet will
predominate and through its core or plunger will lower the other end of the rocker-
bar or lever and release the pressure of the brake cord or its equivalent upon the
brake drum or wheel sufficiently to admit of the latter rotating upon its axis to feed
the carbons together.
In some instances it may be found desirable to cut an oblong slot in the core or
plunger of the shunt coil or electro-magnet and connect one end of the chain or its
equivalent to this core plunger or to attach a weight to the chain, a pin or
projection upon the said weight passing through a hole or holes in the rocker-bar
or lever. Or the chain or its equivalent may be attached to a pivoted weight
secured to any convenient part of the rocker-har or lever. The weight should in
each of the above cases be sufficiently heavy to rest upon the rocker-bar or lever
until such time as the increased tension of the brake chain or its equivalent lifts it
up slightly and carries it round,

page_text: Instead of the above mentioned weight the extremity of the chain or its equivalent
may be secured to a dash pot fixed on the rocker-bar or lever.
Dated this 22nd day of January 1898.
A. F. SPOONER,
323, High Holborn, London, Agent for the Applicants.
improvements in and relating to Electric Arc Lamps.
We, LLEWELLYN BURBANK CODD, of 131, Belgrave Road, Edgbaston, Birming-
ham, in the County of Warwick, Electrical Engineer, and Join ALFRED CODD,
of The General Hospital, Wolverhampton, in the County of Stafford, Doctor of
Medicine, 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:-
Our invention relates to electric arc lamps and has for its object to provide a
simple and efficacious regulating device for striking and maintaining the requisite
length of the arc.
In carrying out our invention we provide a brake drum or wheel having a
peripheral groove adapted to receive a chain, wire, or cord which is passed around
the said drum or wheel, and the ends of which are secured, adjustably or otherwise,
to the rocker-bar or lever carrying the cores or plungers of the coils or electro-
magnets. That end of the said chain, wire, or cord situated at the side of the
rocker-bar or lever carrying the core or plunger of the electro-magnet or coil
wound in shunt, is according to our invention attached at a point closer to the pivot
or fulcrum of the said rocker-bar or lever than the other extremity of the said chain
or its equivalent.
In order that our invention may be clearly understood we will now fully
describe same in reference to the accompanying drawings, in which Fig. 1 is a
sectional front-elevation, and Fig. 2 is a sectional side-elevation showing one
arrangement of our improved regulating device for arc lamps.
We would here state that the lamp referred to in our Provisional Specification is
described as having its brake-mechanism arranged above the coils, but it is more
convenient to reverse this arrangement, and therefore the lamp is herein described
and illustrated as having its mechanism arranged below the coils.
A and B are the two coils or solenoids having cores a and b respectively, the
coil A being series-wound and the coil 13 shunt-wound. CC₁ is a rigid frame
supporting the coils A and B and other mechanism, and D is a rocking lever
pivotted to the cores a and b of the solenoids. The rocking lever D is preferably
composed of a double bar as shown with ends bent around the cores a and b and
held together by screws for the purpose of gripping tightly between them the
ends of the brake chain G as shown, but of course any other equivalent arrangement
may be substituted. The lever is mounted on a spindle E supported in the frame C
in such a manner as to enable it to rock when operated by either of the solenoid
cores. The core of the series-wound solenoid A, or equivalently the series end
of the lever D, is made slightly heavier than the core of the shunt-wound
solenoid B, so that the tendency of the lever D is to lie at an angle as shown in
Fig. 1 of the drawings. The portion of the frame marked C is advantageously of
V-form such as shown, and near its lower end a rotary, brake drum F is mounted
on a shaft f. The said brake drum is located centrally below and in the axial plane
of the solenoids and has loosely wound upon it in a peripheral groove a chain

page_text: or cord G, the ends of which are secured to the respective arms of the rocking
lever D but at unequal distances from the fulcrum thereof.
The end of the brake chain G is connected further from the fulcrum E on the
series side that it is on the shunt-side, and therefore when the rocking lever D
is operated, the former or series-end will move through a larger arc of a circle than
the shorter or shunt-end; thus the brake drum F will receive a rotary motion in
one or the other direction through the action of the solenoids as is hereinafter fully
described.
On the same shaft f which carries the brake-drum is fixed a pair of pulleys HI,
or a double pulley may be employed, and to each of these one end of the cords /
and i is fixed. These cords may be simply led direct to the upper and lower
carbon-frames M and N so that when one is raised the other is lowered. In the
drawings the cords are shown as being wound round the two pulleys in opposite
directions and directed by guide pulleys and i, placed above openings provided
in the bed-plate J, into the interior of slotted or split guide tubes K and L fixed
below the plate J: their lower extremities are secured, the one to the sliding
frame M and the other to the sliding frame N, which carry the carbons. The
arrangement and action is such that the carbons will be advanced or separated
according to the movement of the rocking-lever ) when actuated by the solenoids.
The result of securing the ends of the brake-chain G at unequal distances from the
fulcrum of the rocking-lever D and weighting one end more than the other, is that
when the. lamp is not in use the heavier or series-side and the core a together
with the longer arm of the lever D will descend, thus slackening the chain G
and allowing the brake-drum F together with the pulleys H and I to perform a
limited rotary motion in the direction of the arrow 1. Though the pulleys I and I
turn in the same direction, the winding thereon of the cords and in opposite
directions and their attachments to the upper and lower sliding frames respectively,
cause the carbons to approach one another until they come into contact. Upon
the current being switched on and the series-coil becoming magnetised, the move-
ment of its core will raise that end of the rocking-lever D, and inasmuch as the
brake-chain G is secured at that side at a greater distance from the fulcrum E of
the rocking-lever D than at the other side and is consequently forced to move
through a larger arc, the said brake-chain will be tightened upon the brake-
drum F so as to rotate same on its axis sufficiently to separate the carbons for the
required distance.
Upon the arc becoming too long, the pull of the shunt coil B will predominate
and through the movement of its core will raise that end of the rocking-lever D,
and so release the pressure of the brake-chain G upon the brake-drum F
sufficiently to admit of the latter rotating upon its axle and allowing the carbons
to come together, owing to the superior gravity of the frame M.
Having now particularly described and ascertained the mature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:
1. For regulating the carbon feed in arc-lamps the combination with series- and
shunt-wound magnets of a rotary brake-drum with chain having its ends connected
to the arms of a rocking-lever at unequal distances from the fulcrum thereof, the
distance at the series-side being the greater, and means for imparting the move-
ments of the brake-drum to the carbon carrying frames, the action being such that
when the lamp is at rest the position of the rocking-lever is such that the brake-
chain is slackened and the carbons come in contact, but when current is switched on
the position of the rocking-lever is changed, one of its ends then moving through
a greater arc than the other and so tightening the brake-chain and rotating the
brake-drum sufficiently to separate the carbons and strike the arc, and when the arc
has become too long the shunt-coil moves the rocking-lever in the reverse direction,
slackening the chain and allowing the brake-drum to move sufficiently to readjust
the arc, substantially in the manner herein set forth.

page_text: 2. The improved regulating device for striking and maintaining the arc in arc-
lamps, constructed, arranged or adapted to operate substantially in the manner
berein described and illustrated in the drawings.
Dated this 22nd day of November 1808
For the Applicants,
J. C. CHAPMAN,
Chartered Patent Agent, 70, Chancery Lane, London,. W.C.