AN IMPROVED ELECTRIC ARC LAMP
Year: 1884

page_text: I, ROBERT HOWE GOULD of 2 Hill Street, Peckham, in the County of Surrey
Engineer do hereby declare the nature of my Invention for "AN IMPROVED
ELECTRIC ARC LAMP" and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:-
This Invention has for its object an improved electric arc lamp.
In my improved lamp the carbon holders together with the carbons which they
carry are mounted in inclined positions in such a manner that they appear looked
at from the front as the two equal sides of an isosceles triangle having its apex
downwards. Each carbon is carried by a metal tube or stem and descends by
gravity along a guide tube as the carbon burns away. At its lower end the carbon
abuts laterally against a stop which is carried by an arm connected with the
guide tube.
The axes of the two carbons are not in the same plane but in transverse planes
which would intersect each other if continued some inches below the points of the
carbons. The carbons pass without touching at their lower ends one a little in
front of the other.
One of the carbon holders is hung upon pivots so as to be moveable together
with the stop or abutment which supports the lower end of the carbon and when
no current is passing a spring operating against the pivotted carbon holder brings
the two carbons into contact laterally near their lower ends. When the current
passes, the arc is established by the separation of the carbons. This is effected by
means of an electro maguet, which attracting an armature attached to the pivotted
carbon holder overcomes the spring and produces an interval between the two
carbons of permanent but adjustable length and suitable for the exhibition of
the arc.
In order that my Invention may be most fully understood and readily carried
into effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.

page_text: This latter guide tube is insulated from the frame a by a slab of vulcanite d upon
which the bearings for the pivots are directly fixed. A spring is introduced
between the vulcanite and the guide tube at e and this holds the guide tube
against the regulating wedge f which can be set in or withdrawn by means of a
screw. The other guide tube b has the armature g attached to it and also a stem h
which is encircled by a spring i. The spring abuts upon a nut h¹ on the stem and
also upon a bridge piece a¹ attached to the frame a. The stem passes through a
hole in the bridge piece a¹. k is an electro magnet fixed upon the frame a, when
this magnet is excited by a sufficient current passing in its coils it attracts the
armature g overcoming the spring i.
Two metal tubes and m pass down through the guide tubes b and c; they
descend by gravity whenever free to do so between the rollers nn. One of these
rollers is carried upon a spring arm, I may however dispense with the rollers.
The carbons o and o¹ of the lamp pass down through the inner metal tubes
and m and they are clamped in them by the set screws l¹ and m¹.
The guide tubes b and c also have arms p and q fixed to them and these at their
lower ends carry stops rr on which the carbons abut.
These stops of any suitable refractory material but preferably of marble are held
in holders having square stems which are received into sockets at the lower
ends of the arms p and q. The stems are pressed forward by springs the backward
play of which is limited by set screws as the Drawing indicates. p and q are
pieces clipped on to the arms p and q they have eyes at their ends through which
the carbons pass they aid in guiding and steadying the carbons. 222 and q² are
wire brushes attached to the arms p and q and pressing upon the tubes 7 and m to
ensure good electrical connection. The circuit of the lamp is from the positive
terminal, through the coils of the electro magnet k to the guide tube b; thence to
the inner tube and the carbon o. From carbon o the current passes to carbon o¹,
and so to tubes m and c and the negative terminal of the lamp. Assuming the
carbons to be in contact when the current first passes the electro-magnet / by
attracting its armature separates them and establishes the arc.
k
If from any cause the arc should fail the armature g is drawn away from 'the
magnet by the spring i and so the carbon o is brought again into contact with the
carbon of and the arc is again established. The carbons as they burn away
descend by their own weight and that of the tubes and m until the lower
ends of the carbons which always assume a taper form bear laterally upon the
stops r, r.
*
I prefer to wind the electro magnet k with two coils-an inner coil of stout wire
in series with the arc and an outer coil of fine wire shunting the arc and so
connected as to oppose itself to the inner coil upon the magnet.
Sometimes in place of stops against which the carbons bear laterally as
described I use refractory stops which have holes of a slightly taper form drilled
in the projecting ends in which the carbons fit.
The arc is in this case established below the holes. On the top of all the
refractory stops I may fix plates of suitable metal which plates are protected from
extreme heat by the body of the refractory stop intervening between them and
the arc.
In existing electric lamps where the size of the arc is fixed no provision is made
for the automatic lighting and relighting of the carbons; my lamp not only does
this but when so called "flaring" takes place the electro magnet k partially releases
the armature g and by lessening the length of the arc, stops the flare.
In the case of lighting the lamps by means of a so called continuous current
dynamo machine, the positive carbon should be proportionately thicker, than the
negative one; When I use an alternating current machine, I place carbons of
.equal size in the lamp.
This lamp is found to give a very steady light because the distance between the
carbons remains constant whilst the lamp is in action.

page_text: Sometimes instead of the foregoing modes of regulating the downward feed of
the carbons, I allow two sticks of suitable refractory material preferably marble
to feed downwards towards and against the points of the carbons in such a manner
that they form an acute angle with the latter as indicated by Figure 3-they are
guided by suitable tubes or sockets, and are taper at the points which abut against
the carbons. In the case of these marbles being of round section,-
-a screw of
steep pitch is cut on the circumference of each, and in each guide tube-a set screw
with a smooth point is inserted as indicated in the Drawing which compels the
marbles to revolve on their own axes, on moving downwards and thus continually
expose a fresh surface to the points of the carbons, if the marble sticks are of
square or other section they can be fitted into hollow holders which can be treated
in the same manner as above described in reference to the round marble sticks,
thus acting in their downward course in the same manner as the latter; i.e.,
revolving axially.
The action that takes place will be as follows:-As each carbon and its belonging
marble stick both abut against each other they cannot go further down than their
gradual consumption allows, the carbon feeds downwards as it is consumed, and as
the marble crumbles away it also feeds downwards by its own gravity, but neither
carbon nor marble can get ahead of the other. I may also cause the carbons
themselves to feed down helically.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is:-
First. An electric arc lamp in which the carbons are inclined the one to the
other and cross or pass each other and are made to abut against stops whereby a
distance between them suitable for the exhibition of the arc is maintained
substantially as described.
Second. My improved electric arc lamp substantially as described.
CARPMAEL & Co.,
Agents for the Applicant.