IMPROVEMENTS IN ELECTRIC LAMPS OR LIGHTING APPARATUS
Year: 1882

page_text: LETTERS PATENT to Sydney Ferris Walker and Francis Gervase. Olliver,
both of Cardiff, in the County of Glamorgan, Electrical Engineers, for an
Invention of "IMPROVEMENTS IN ELECTRIC LAMPS OR LIGHTING APPARATUS"
PROVISIONAL SPECIFICATION left by the said Sydney Ferris Walker and
Francis Gervase Olliver at the Office of the Commissioners of Patents on the
7th October 1882.
SYDNEY FERRIS WALKER and FRANCIS GERVASE OLLIVER, both of Cardiff, in
the County of Glamorgan, Electrical Engineers "IMPROVEMENTS IN ELECTRIC
LAMPS OR LIGHTING APPARATUS
">
Our invention relates to electric or voltaic arc lamps and is designed to provide
the same with improved feed mechanism to be applied to one or both of the carbons
or electrodes to determine or regulate their approximation to each other and thereby
prevent variations or fluctuations of the light:
For this purpose we combine with one or both of the electrodes a clutch which.
is arranged, controlled and operated in such a manner that the electrode to which
it is applied will be thereby held or drawn back or permitted to approach the other
electrode in proportion to the rate of combustion of the electrodes.
For this purpose we employ the following mechanism, which we will describe
more particularly with reference to a lamp in which only the upper electrode is
provided with a clutch, although we wish it distinctly understood that the
said mechanism is equally applicable to lamps in which both electrodes move.
In our said lamp we place an electro-magnet, or pair of such magnets, whose coils
are included in the main circuit, that is to say, the circuit in which the arc is
produced. The armature of the said magnet or magnets is connected with one end
of a lever whose other end is supported by a spiral or other spring. The end of
this lever which is connected with the said armature (and which we will term the
armature lever) is arranged in combination with a lever forming part of the
aforesaid clutch, and the intermediate part of the said armature-lever bears upon
a disc operated by an electro-motor included in a shunt circuit. The said armature-

page_text: •
lever may be provided with an adjustable screw to act upon. the clutch-lever. The
said electro-motor has on its shaft a worm or pinion which gears with a wheel on
or connected with the disc. On one part of the periphery of the said disc we form
n flat surface or a number of such surfaces each of which we usually provide with a
screw or other device for regulating the extent of the movement of the lever due
to the action of the disc, as hereinafter described.
While the lamp is working the rotative part of the said. motor turns rapidly
and brings the aforesaid flat portion or portions of the disc's periphery, or the
regulating device thereof, periodically into contact with the intermediate part of
the said armature-lever, which is then raised by the spring, thereby depressing its.
end which is in contact with the clutch-lover so that the latter drops and releases the
upper electrode, which then approaches the other electrode. At the moment when
the two electrodes are in contact, the resistance of the main circuit is so slight
compared with that of the motor that practically no current passes through the
Intter, and the motor stops or would stop but for the instantaneous rising of the
armature and consequent separation of the electrodes and renewal of the arc and
of the resistance thereat.
The amount of the current which passes through the shunt and motor will be
directly in proportion to the length of the arc, that is to say, to the resistance of
the main circuit at the part where the arc is formed and the energy or force of the
electro magnet or magnets will vary inversely to such resistance; therefore the
speed of the motor will be directly in proportion to this resistance; and it is
obvious that the frequency of the contact of the Bat surface or surfaces of the disc
with the armature-lover, and consequently the periodical action of the said lever
and the clutch, will vary with the speed of the motor, therefore the feed mechanism
will act in accordance with the requirements of the lamp as determined by the
amount of current supplied to the are and the consequent consumption of the
carbons.
In some instances, we provide an adjustable resistance for further regulating
the speed of the electro-motor, but this will not usually be necessary as the motor
will be so adjusted to the current and resistance of the lamp as to be automatically
regulated according to the variations of the arc.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Sydney Ferris Walker and Francis Gervase Olliver in the Great
Seal Patent Office on the 7th April 1883.
SYDNEY FERRIS WALKER, and FRANCIS GERVASE OLLIVER, both of Cardiff, in
the County of Glamorgan, Electrical Engineers, "IMPROVEMENTS IN ELECTRIC-
LAMPS OR LIGHTING APPARATUS
"
Our invention relates to electric or voltaic arc lamps and is designed to provide
the same with improved feed mechanism to be applied to one or both of the carbons
or electrodes to determine or regulate their approximation to each other and thereby
prevent variations or fluctuations of the light.
For this purpose we employ a rotating disc (with projections or depressions
on its peripheral surface), operated by an electric or other motor, in combination
with a lever connected with a clutch which is arranged, controlled and operated
in such a manner that the electrode to which it is applied will be thereby held
stationary or withdrawn from, or permitted. to approach, the other electrode in
proportion to the rate of consumption of the said electrodes.
We will describe the said feed mechanism more particularly with reference to
a lamp in which only the upper electrode is provided with a clutch, although we
wish it distinctly understood that the said mechanism is equally applicable to
lamps in which both electrodes move. In our said lamp we place an electro-
magnet, or pair of such magnets, whose coils are included in the main circuit, that
is to say, the circuit in which the arc is produced. The armature of the said
magnet or magnets is connected with one; end of a lever whose other end is
supported by a spiral or other spring. This lever (which we will term the
armature-lever) is arranged in combination with a lever forming part of the
aforesaid clutch and the said armature-lever bears upon a disc operated by_an
electro-motor included in a shunt circuit, or by any other suitable motor. The
said armature-lever or the lever of the clutch may be provided with a screw for
the purpose of adjusting the said levers relatively to one another. The said electro-
motor has on its shaft a worm or pinion which gears with a wheel on, or connected
with, the disc. On the periphery of the said disc we form a flat surface or a
number of such surfaces each of which we usually provide with a screw or other
device for regulating the extent of movement of the armature-lever as hereinafter
described, or we may provide, instead of the flat surface or surfaces and the screws,
a projection or projections on the periphery of the disc.
One mode of carrying our said invention into practice is illustrated, by way of
example, in the accompanying drawing, in which.
Figure 1 represents a sectional side elevation of an electric arc lamp, with our
improvements applied thereto.
Figure 2, is a sectional side elevation of the same, drawn to an enlarged scale,
with the electro-motor removed.
Figure 3 is a plan, partly in horizontal section, also drawn to an enlarged scale,
showing the clutch.
a represents the upper carbon or electrode and 6 the lower carbon, c is an electro-
magnet whose coil is included in the main-circuit, d is the armature connected to
one end of the lever e, the other end of which lever is supported by a spiral

page_text: spring. This end of the said lever bears upon a disc arranged to be operated
by the electro-motor which is included in a shunt circuit and whose shaft is
provided with a worm j. This worm gears with the toothed wheel e fixed on the
shaft carrying the disc g. The lever e is arranged to act upon the lever 7 of the
clutch m in the manner hereinafter described, and a set-screw is inserted in
the lever e for the purpose of adjusting the said levers relatively to each other;
g' is a flat surface formed on tho disc g, and o is a screw inserted therein for the
purpose of regulating the extent of movement of the lever e caused by the said
screw as the same passes the said lever during the rotation of the disc. The
clutch m. is made tubular and of such diameter that the electrode a can move
freely therein. At its upper end, half of the tube is removed and a flat plate
forming the clutch-lever is pivotted to the remaining half of the tube, an adjustable
plate.being secured to the upper side of the lever 1, which plate can be moved
towards, or away from, the electrode, if desired, and secured to the lever by screws,
so that the electrode will always be held by the clutch while the latter is not acted
upon by the rotating disc..
We provide a rest or support for the clutch mand means for moving the said
rest up under the clutch by the action of the armature when lifted, and for moving
it out of the way of the clutch as the armature doscends.
In the apparatus shown in the drawing, this rest or support consists of an
excentric p, Figure 2, mounted upon a shaft p carried in bearings in the bracket p².
An arm or lever 2 is fixed at one end on the shaft pand its other end rests upon
a bent arm g fixed to the armature d. The excentric p is so adjusted that, when
the armature d is lifted, the excentric will be raised and at the same time moved.
under the clutch m, and when the armature descends the excentric will be lowered
and withdrawn from the said clutch. s represents an adjustable rest for the clutch.
The circuit connections are made so that the current from the source of electricity
passes through the coil of the electro-magnet c to the upper electrode, through the
upper and lower electrodes and thence through one of the rods of the lamp fraine
to the terminal to which the negative wire is attached. The shunt circuit for
the motor is taken from the main circuit as shown in Figure 1. The lower
electrode is insulated from the lamp-frame; and the motor the magnet, and the
positive terminal are also insulated from the lamp-frame.
The operation of the lamp may be explained as follows, that is to say, the
If the
rotative part of the said motor turns rapidly and rotates the disc g.
periphery of the latter had been uninterruptedly circular, the lever e and the clutch,
which in its normal position holds the electrode a by the frictional contact of one
part of the clutch therewith, would not be moved by the rotation of the said disc.
But with the disc g constructed as described, its rotation brings the screw o
periodically into contact with the lever e which is thus depressed at each revolution
of the disc, the spring being compressed, thereby permitting the clutch-lever to
descend sufficiently to release the upper electrode a which is then free to approach
the lower electrode. At the moment when the two electrodes are making contact,
the resistance of the main circuit is so slight compared with that of the motor that
practically no current is passing through the latter and the motor would stop, but
at this moment the armature being raised by the attraction of the magnet, lifts the
levere and raises the clutch thereby withdrawing the electrode a from the
electrode band causing the renewal of the arc and of the resistance therent, and
the current again flowing through the shunt and motor, the latter continues its
rotation and operation of the clutch as above described.
The amount of current which passes through the shunt and motor will be
directly in proportion to the length of the are, that is to say, to the resistance of
the main circuit at the part where the arc is formed, and the energy or force of the
electro-magnet or magnets will vary inversely to such resistance, therefore the
speed of the motor will be directly in proportion to this resistance; and it is

page_text: obvious that the frequency of the contact of the screw or screws on the flat surface
or surfaces of the disc with the armature-lever and, consequently, the periodical
action of the said lever and the clutch will vary with the speed of the motor, the
feed mechanism will, therefore, act in accordance with the requirements of the lamp
as determined by the amount of current supplied to the arc and the consequent
consumption of the carbons.
After the clutch has been lifted by the action of the armature, the rest or
excentric p under the clutch m supports the latter when the lever is depressed to a
slight extent by the rotating disc, and thus permits the electrode to slip a very short
distance through the clutch. The said rest also prevents the displacement of the
said clutch which without this support would be liable to move up and down
without feeding. Moreover the space between the said rest and the clutch limits
and determines the extent of the tilting movement of the lever e by. the rotating,
dise and enables us to ensure the slight feed movement upon which the efficiency of
our lamp mainly depends.
When our improved mechanism is applied to both electrodes,, the latter are
arranged either horizontally or vertically, in the latter case a spring, or other
suitable device is employed for causing the lower electrode to approach the upper
one when released by the clutch, the arrangement of the mechanism being sub-
stantially as above described. When the electrodes are arranged horizontally a
spring or the like must be applied to each electrode. We sometimes arrange one
set of feed mechanism to operate two electrodes, by employing chains and pulleys or
other suitable devices.
In some instances we provide an adjustable resistance for further regulating the
speed of the electro-motor, but this will not usually be necessary as the motor will
be so adjusted to the current and resistance of the lamp as to be automatically
regulated according to the variations of the arc and of the strength of the current.
We have ascertained by experiment that we can obtain a feed movement of one
four-hundredth (1) of an inch and we sometimes arrange the motor to feed this
amount at each revolution of the disc, and, if the lamp, with a given strength of
current, consumes the carbons at the rate of one four-hundredth (400) of an inch in
one second, we arrange for the feed movement to take place once in every second;
if the lamp consumed the carbons at the rate of one two-hundredth (200) of an
inch in a second, we should arrange for the feed to take place twice in every
second. Having so arranged the mechanism for any lamp, it becomes self-regulating
within very wide limits; because if the carbons are, from any cause, consumed
either faster or slower, the feed takes place faster or slower in proportion.
As long as the lamp is burning properly and the current does not fall below a
certain strength, the carbons do not come in contact. Should they accidentally do
so however the motor will stop.
As above stated the speed of the motor is directly in proportion to the resistance
or to the length of the arc, we would further point out that, with a given length of
arc, should the engine race, or should there be, from any cause, an increase of
current, causing an increased consumption of carbon, the speed of the motor will
increase to compensate therefor and vice versa.
Having thus fully described our said invention and the manner of performing
the same we wish it understood that we claim :-
First. In an electric arc lamp, the employment of a rotating disc (with projections
or depressions on its peripheral surface,) operated by an electric or other motor, in
combination with a lever connected with a clutch which governs the feed of the
carbon or electrode, all substantially as set forth.
Second. In combination with the said clutch and rotating disc, the electro-
magnet or magnets included in the main circuit and the armature carried by, or
connected with, the lever which bears on the said disc, substantially as set forth,
and operating as, and for the purpose, specified.

page_text: Third. The use, in combination with the said clutch, of the rest arranged to be
operated by an arm attached to the said armature, substantially as, and for the
purpose, specified.
In witness whereof I the said Sydney Ferris Walker for myself and on behalf
of the said Francis Gervase Olliver have hereunto set my hand and seal.
this Sixth day of April in the year of our Lord one thousand eight hundred
and eighty three
SYDNEY FERRIS WALKER (L.S.)