Improvements in Electric Arc Lamps.
Year: 1899

page_text: Date of Application, 20th July, 1899
Complete Specification Left, 3rd Apr., 1900-Accepted, 19th May, 1900
PROVISIONAL SPECIFICATION.
Improvements in Electric Arc Lamps.
We, JOHN BRUNSWICK BARTON, Engineer, of 35, Rue de Bagnolet, Paris, and
Messrs. THE JANDUS ARC LAMP AND ELECTRIC Co. LTD., of Victoria Works, Old
Charlton, Kent, Engineers, do hereby declare the nature of this invention to be
as follows -
Our invention relates to mechanism for feeding the carbons in electric arc lamps,
and has for its object to simplify the construction of such mechanism, and to
enable the production of an exceedingly simple lamp capable of working econo-
mically and steadily and of being very cheaply constructed.
Our invention consists in an improved are lamp having the main features here-
inafter described.
In carrying our invention into effect according to one modification we provide
a solenoid fixed to the upper portion of the lamp frame. This solenoid we pro-
vide with an iron core with a special disc top to be further described. We close
the bottom of the solenoid so that the inner tube of the solenoid acts as a dashpot
with the core acting as a plunger or piston in it. In the bottom of the solenoid we
provide a suitable valve which permits only of limited egress of air but opens
freely when the plunger is raised.
On the top of the plunger we provide a relatively thin iron disc, slightly larger
than the outside diameter of the solenoid itself. We find that this iron disc has
the effect of greatly damping the motions of the carbons and steadying the arc.
The solenoid core with the iron disc attached is suspended from a pivoted pulley,
one half of which is of fairly large diameter, and the other half of which is much
smaller. The core is suspended from the large half of the pulley by means of a
chain, so that it has a vertical motion. From the smaller diameter half-pulley
a tubular carbon holder is suspended. This tubular carbon holder is suitably
weighted and connects with the carbon, which passes out of it, by means of loose
clutch rings or some other suitable carbon feeding clutch device.
In this arrangement the core of the electro-magnet or solenoid moves through
twice the distance that the carbon moves through, as the half pulley on which
the electro-magnet core is suspended is twice the diameter of that from which the
carbon holding and feeding device is suspended, and this makes the arc less sen-
sitive to vibrations of the electro-magnet core and less liable to pumping. The
iron disc, above described, attached to the electro-magnet core at its top, has
also the effect of steadying the are and preventing very great fluctuations, as the
disc, we find, takes a sort of floating position which very much aids in keeping
the lamp burning steadily, without requiring a very powerful dash pot with its
attendant disadvantages. The bottom of the inner tube of the solenoid is pro-
vided with a valve which opens freely, on the upward stroke of the electro-magnet
core, and with a downward movement of the electro-magnet core the valve closes,
allowing only a restricted opening so that a suitable dash-pot effect is obtained,
greatly aiding in the steadying of the arc.
We suitably load the carbon holder to provide the required approximate balance

page_text: between it and the weight of the electro-magnet core; the carbon holder being left
somewhat the heavier.
In the bottom of the carbon holder we provide clutch rings of a usual type
between which the upper carbon is held in the action of the lamp.
These clutch rings are supported in slots in a ring the ends of the slots being
inclined and pins being provided to prevent the rings falling out when the carbon
is withdrawn.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and 25, Cross Street, Manchester,
Agents,
Improvements in Electric Arc Lamps.
We, JOIN BRUNSWICK BARTON, of 35, Rue de Bagnolet, Paris, France,
Engineer, and THE JANDUS ARC LAMP AND ELECTRIC CO., LTD., of Hartham Works,
Hartham Road, Holloway. N., Engineers, lato of Victoria Works, Old Charlton,
in the County of Kent, 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:-
1
Our invention relates to mechanism for feeding the carbons in electric arc lamps
and has for its object to simplify the construction of such mechanism and to allow
of the production of an exceedingly simple lamp capable of working economi-
cally and steadily and of being very cheaply constructed.
Our invention consists in an improved arc lamp in which the main features are
a double supending wheel having a loaded positive carbon holder suspended from
its smaller radius and a dashpot-controlled electro-magnet plunger or core with a
suitably shaped steadying disc suspended from its larger radius.
Referring now to the accompanying drawings which illustrate our invention:--
Figure 1 is a sectional elevation of an arc lamp constructed according to our
invention, and
Figure 2 is an inverted plan of the carbon holder.
In carrying our invention into effect as applied in a constant potential lamp we
provide a solenoid a fixed to the upper portion of the lamp frame.
This solenoid we provide with an iron core b having a special disc top c to be
further described hereafter. We close the bottom of the solenoid by a cover d so
that the inner tube e of the solenoid acts as a dashpot with the core b acting as a
plunger or piston in it; in the bottom of the solenoid we may provide a suitable
valve f which permits only of limited egress of air when the plunger is descending
but opens freely when the plunger is being raised.
The disc c is of relatively thin iron plate and is somewhat greater in diameter
than the outside of the solenoid. We find that this iron disc has the effect of
greatly damping the motion of the upper carbon and steadying the arc. The
solenoid core or plunger with the iron disc is suspended from a pivoted pulley g
one half of which is of fairly large diameter while the other half k is much
smaller. The core is suspended from the large half of the pulley by means of a
chain so that it has a vertical motion. From the smaller half pulley a tubular
carbon holder m is suspended by means of a chain n. This tubular carbon holder
is suitably weighted preferably by means of a lead ring t and connects with the

page_text: carbon o which passes out of it by means of loose clutch rings p of a usual con-
struction. These clutch rings are supported in slots q in an annular piece the
ends of the slots being inclined and a ring s being threaded through the clutch
rings and the piece r to prevent the former falling out when the carbon is
withdrawn.
In this arrangement the core or plunger b moves through twice the distance that
the carbon moves through as the radius of the half pulley his twice that of the
half pulley k. This makes the arc less sensitive to vibrations of the electro-
magnet core and less liable to pumping. The iron disc c attached to the electro-
magnet core at its top has also the effect of steadying the arc and preventing very
great fluctuation therein, as the disc, we find, takes up a sort of floating position
near the top of the solenoid a. This very much aids in keeping the lamp burning
steadily without requiring a very powerful dashpot with its attendant disadvan-
tages. The dashpot arrangement before mentioned formed of the core band
inner tube e of the solenoid also greatly assists in steadying the arc. We suit-
ably load the carbon holder to provide the required approximate balance between
it and the weight of the electro-magnet core the carbon holder being left some-
what the heavier. The resistance is placed on insulators in series with the
lamp as usual.
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. An electric arc lamp characterized by a suspension system formed of two
parts, the larger carrying the electro-magnet core moving in its dashpot and the
smaller carrying the carbon holder, the said carbon holder being loaded and
having a clutch device, the whole being adapted to steady the movements of the
carbon feeding device and prevent pumping substantially as described.
2. In an electric arc lamp as claimed in Claim 1 an electro-magnet core formed
with an enlarged portion at its top adapted to move in the magnetic flux and to
steady the motions of the core, substantially as described.
1.
MARKS & CLERK,
18, Southampton Buildings, London, W.C.,
13, Temple Street, Birmingham, and 25, Cross Street, Manchester,
Agents.