Improvements in Arc Lamps.
Year: 1894

page_text: Date of Application, 31st Jan., 1894
Complete Specification Left, 29th Nov., 1894-Accepted, 12th Jan., 1895
PROVISIONAL SPECIFICATION.
Improvements in Arc Lamps.
FREDERICK BROWN, Fairyfield, Highgate, Walsall, Electrical Engineer, and
CHARLES HERBERT OFFORD Tasker Street, Walsall, Electrician do hereby
declare the nature of this invention to be as follows:-
The current to the carbons is carried through a wire wrapped to form a solenoid,
the core of which is either directly or through a lever attached to a band of metal,
leather or other suitable material, which passing round a brake wheel, to the axle
of which wheel is attached a pinion, which pinion gears into a rack on the rod
which carries the carbons. Upon switching on the current the core is drawn into
the solenoid, tightening the band round the brake wheel and pulling the wheel
As
round thus through the pinion raising the carbon rol and striking the arc.
the arc burns the band slackens and allows the brake wheel to turn and the carbon
The
rods to come nearer together by gravity thus maintaining a steady arc.
pressure on the brake wheel can be varied either by the means of springs or
weights as may be desired.
January 30th 1891
FREDERICK BROWN.
CHARLES H. OFFORD.
Improvements in Arc Lamps.
We, FREDERICK BROWN, Fairyfield, Highgate, Walsall, Electrical Engineer,
and CHARLES HERBERT OFFORD, Tasker Street, Walsall, Electrician, 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 improvements in arc lamps, or that class of electrical
lamps in which a current is sent through two stout carbon rods, with their opposed
ends separated through the medium of a regulator, in which our improvements
primarily reside.
Thus our invention pertains to meaus for keeping the opposed ends of the
carbon rods (as they slowly consume) at a constant distance apart, so that whether
the current be alternating or direct, the length of the arc is kept constant, and
further, steadiness and freedom from flickering in the light are attained.
The arc lamp consists essentially of a frame, having located within it, depending
shunt and main solenoids, the former wrapped with fine wire, and the latter with
the coarse wire and lying within the main circuit, and each having directed up
their middles, soft iron cylindrical bars or cores, each having a connection at their
lower ends to a rock lever, supported from the lower ends of the solenoids, whilst
the terminal end of the core bar of the main solenoid is connected to a band brake,
partly encircling the periphery of a wheel, whose axis carries a pinion intergearing
with the teeth of a rack bar, working within guides, and having at its lower end,
the positive carbon holder, whilst the upper end is connected to a cord, passing
over a hanging pulley, supported upon the top of the general framing, and having

page_text: 3
its other end connected to a sliding bar, directed through and working within
guides, and with the lower end carrying the negative carbon holder, so that as
pressure of the brake band is relieved from the wheel or drum, so the positive
carbon descends and the negative carbon ascends to it, hence the mutual approach-
ment of the carbons, which are regulated to give a required length of arc.
It will thus be seen that in case of an alternate current, then the position of the
arc relative to the lamp is constant, but in case of a direct current, then the arc
slightly changes its position relative to the lamp, consequent upon the unequal
consumption of the carbons.
Figure 1 of the accompanying drawings represents partly in vertical section,
and partly in elevation, an arc lamp, constructed, arranged and provided with
regulating means in accordance with our invention, and with parts broken away
in order to show more clearly, the important features of our improvements.
Figure 2 represents a vertical section of the said lamp at a right angle to that
of Figure 1, but with the principal parts of the lamp in elevation, that is, the
controlling means whereby the carbon points are mutually brought towards each
other on the consumption of their opposed ends, which on approaching within a
certain distance, strike the arc, and the carbons are held.
Figure 3 represents a like vertical section as Figure 1, but with certain parts
(such as the main solenoid) removed, in order to show more clearly the hanging of
the rack rod and lower carbon rod, and with the lower part of the soft iron core
of the shunt solenoid also removed.
Figure 4 represents a like section as Figure 2, but with the lamp turned slightly
round in order to show the rocking lever connecting the soft iron cores of both
solenoids, whilst the carbon carriers of the lamp are removed.
Figure 5 represents a cross section of Figure 4 upon the dotted lines x-x.
Figure 6 represents a section of the rack rod upon the dotted line A, showing
the groove within its side to receive the end of a pinion, to prevent the said rod
from turning when making its traverse.
The same letters of reference indicate corresponding parts in the several figures
of the drawings.
a is a main solenoid, which does the work of an ordinary electro-magnet,
suspended from and connected to the underside part of the top or cover, of an
encircling casing b, provided with a bottom 62, and with the outside of the said
top, carrying binding screws c, c', for clamping the main circuit wires. Directed
up the middle of the main solenoid wire, which is wrapped with stout wire and lies
within the main circuit, and through which the whole current passes when the
carbons have struck the arc, is a soft iron core d, with its lower end part d',
embraced by a fast clip d², to which the end e', of a double armed rocking beam
or lever e, jointed at e, is pivotedly connected by trunnion pins e. Now this beam
lever is supported and carried by a hanging bracket a', attached to the lower end
caps a³, 3, of main and shunt solenoids a and f, respectively. The other end e²,
of the said lever is horizontally and pivotedly connected at e, to a boss ², made
fast to the lower end g', of a soft iron core g, directed up the middle of the shunt
solenoid f, which is wrapped with fine wire of high resistance, and is connected so
as to form a shunt to the arc. This said shunt coil is supported in common with
the main coil a, to the inside top of the cover bl.
The termination of the soft iron core d, of the solenoid a, has a weight d, made
fast upon it, and is jointedly connected to a band brake h, (also jointedly connected
to the stalk j¹, of a pressure spring j, working within a tubular and fast bracket j²,
carried by an adjustable rod 13,) by a link i. This brake band h, embraces one half
part of the circumference of a brake wheel k, having made fast to it, or to its axis k³,
which turns within adjustable bearings at the upright brackets ³ (see Figures 1
and 2) a pinion, which intergears with the teeth m¹, of a suspended rack
rod m, working within suitable guides, and carrying at its lower end the positive
carbon holder m², for receiving the positive carbon 1, whilst its upper end is
connected to and hung from one end of a band or wire m³, passing and rimming

page_text: upper end n', of a vertically sliding or rising and falling rod n, working between
guides, and carrying at its lower end, the negative carbon holder o, fitted with
a negative carbon 2.
The ends of the framing are supported and connected by stay rods p, to one
of which, the bracket j, of the brake-pressure regulating spring, is connected.
9 is the main circuit, and r the by-pass wire.
s is a dash-pot containing glycerine or like fluid or only air, and s', is a
piston, working therein and carried by a rod 2, jointed to the lower end of
the soft iron core g, of the shunt solenoid f. By this means, a buffer is formed
and sudden movement and pulsations in the carbons is avoided. The rocking
beam e has at its ends, stops or fingers 6, 7, for limiting the upward movement
of the wires of the respective solenoids. Instead of regulating the pressure of
the brake by a spring, weights may be employed.
OPERATION.
Assuming that the opposed ends of the carbons are separated from each other
to a distance greater than the striking distance of the ar, then switch on the
current in the ordinary way, when the same is shunted through the shunt
coil f, and by electrical attraction, the core g, is drawn or sucked up the
interior of it, and the beam e, is turned and the one end e¹ is lifted and the
other ende, depressed by which latter, the pressure of the brake bind, is
relaxed, and the brake wheel k, is allowed to rotate and be pulled round by
the descent (through its own weight) of the rack rod m, having at its lower
end, the positive carbon rod 1 and its holder m². The fall of the rack rod
gives a con-current ascent to the sliding rod n, and its negative carbon 2, and
holder o, through the medium of the band m, running over the pulley m²,
hence the approachment of the carbons, which, on striking the arc, are instantly
arrested by the current being now diverted through the carbons and across the air
space between them, from which carbons it is conducted to the main solenoid a,
which, in its turn, attracts or sucks up its core d, whereby the beam lever is
rocked in the reverse direction, and the brake band drawn tightly upon the
periphery of the brake wheel, thereby locking the carbons in their regulated
positions.
This transferring of the current for the regulation or adjustment of the carbons
is repeated until the said carbons are consumed.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is-
First. In arc lamps, braking, locking or controlling the carbon holders, or the
carrier rods of them, through the medium of a band brake, with or without a
pressure spring, substantially as described and set forth.
Secondly. In arc lamps, braking, locking or controlling the carbon holders, or
the carrier rods of them, through the medium of a band brake and brake wheel,
a pinion of which latter intergears with teeth upon one of the said rods, and which
braking is governed through the medium of a rocking beam connected to the ends
of the soft iron cores of main and shunt solenoids, substantially as and for the
purpose as described and set forth.
Thirdly. In arc lamps, the combination with a rack bar, having at its end, a
carbon holder, of a band and wheel brake, substantially as and for the purposes as
described and set forth.
Fourthly. In arc lamps, the combination with a brake band and brake wheel, of
a rocking beam or jointed lever, connecting the soft iron cores of the solenoids,
substantially as and for the purpose as described and set forth.

page_text: Fifthly. In arc lamps, the combination with shunt and main solenoids, having
their soft-iron cores united by a beam, of carbon holders or carrier rods, con-
trolled by a band-brake and wheel, and suspended from, and worked in unison
and in opposite directions by, a give-and-take band passing over a pulley or
equivalent, substantially as described and set forth.
Sixthly. In arc lamps, the general construction, arrangement and combination
of the parts, substantially as and for the purpose as described and set forth.
Dated this 28th day of November 1894.
FREDERICK BROWN,
CHARLES HERBERT Offord,
By Henry Skerrett,
6, Livery Street, Birmingham, Agent for Applicants.