IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1882

page_text: LETTERS PATENT to Andrew Betts Brown of Edinburgh, in the County of
Midlothian, North Britain, Engineer, for an invention of "IMPROVEMENTS
IN ELECTRIC ARC LAMPS."
PROVISIONAL SPECIFICATION left by the said Andrew Betts Brown at the
Office of the Commissioners of Patents on the 19th April 1882.
ANDREW BETTS BROWN, of Glasgow, in the County of Lanark, North Britain,
Engineer, "IMPROVEMENTS IN ELECTRIC ARC LAMPS."
This Invention has for its object, by a combination of simple automatic con-
trivances to obtain on the one hand a feed or progressive movement of the carbon
or carbons of an electric arc lamp very closely according with the actual gradual
consumption of the carbons, and on the other hand to secure the speedy readjustment
of the carbons to the desired are distance apart whenever they from any cause
become so far separated that the current cannot pass.
In carrying out the Invention the feed movement of the carbon or carbons is
effected by the weight or pressure of a piston and parts attached thereto, the
piston working in a cylinder and pressing on a liquid which has egress only
through a small port, formed in a port face having on it a small slide valve the
position of which regulates the egress of the liquid and consequent movement of
the carbon or carbons. The valve is connected to the iron core of a solenoid and
to an adjustable spring, the current passing through the solenoid coils being that
which forms the luminous arc, and tending to move the core so as to close the
valve in proportion as the current passing is stronger, whilst the spring is arranged
to act oppositely and to tend to open the valve whenever the current becomes
weaker. The piston or a part moving therewith carries the carbon in a tubular
or other suitable holder, in which holder the carbon is cabable of moving the
current being led to it through a flexible coil or spiral. The carbon is ordinarily
held in its holder by a lever acting on it with an eccentric or other su table
gripping device which only acts when the lever is being raised or held up. When
the current is passing all right the gripping lever is held up either by the core of
Pion 627

page_text: the solenoid which regulates the progressive or feed movement, or by a separate
solenoid or electro magnet; but when the carbons, become so far separated that
the current cannot pass, the gripping lever becomes released, and allows the upper
carbon to descend into contact with the lower one. The current then passes again
and the solenoid or electro magnet raises the gripping lever again, and the gripping
lever in rising lifts the upper carbon the proper distance for the predetermined
length of arc. The gripping lever is proportioned and arranged to give the
proper amount of lift for the required arc, and its descent may be regulated by an
adjustable stop.
In one modification the port face with the valve arranged to move vertically
and a solenoid arranged for both regulating the feed and for readjusting the arc
are carried upon and move with the piston." The gripping lever is connected by a
spring to the solenoid core which is vertical and which is held up by a second
stronger spring. The spring which holds up the solenoid core may be adjustable
by means of a screw only, or in addition there may be one or more solenoid coils
arranged to act so as to vary the tension of the spring and thereby alter the arc
distance, the current or currents through such solenoid coil or coils being the main
current or a shunt current therefrom or a separate current arranged to give control
by hand adjustment at any convenient distance. In order that when the valve
which controls the piston is closed or nearly so, the movement of the piston in its
cylinder may be stopped notwithstanding possible leakage past the piston or
otherwise the valve or a rod connected to it is also connected to a toggle-lever
or wedge or other jamming device acting between the piston and its cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Andrew Betts Brown in the Great Seal Patent Office on the
18th October 1882.
ANDREW BETTS BROWN, of Edinburgh, in the County of Mid Lothian, North
Britain, Engineer. "IMPROVEMENTS IN ELECTRIC ARC LAMPS."
My said Invention has for its object, by a combination of simple automatic
contrivances, to obtain on the one hand a feed or progressive movement of the
carbon or carbons of an electric arc lamp very closely according with the actual
gradual consumption of the carbons, and on the other hand to secure the speedy
readjustment of the carbons to the desired arc distance apart whenever they from
any cause become so far separated that the current cannot pass.
In carrying out my Invention the feed movement of the carbon or carbons is
effected by the weight or pressure of a piston and parts attached thereto, the
piston working in a cylinder and pressing on a liquid the egress of which is
controlled in the manner described in the Specification of Letters Patent granted
to William Falconer King and to me the said Andrew Betts Brown, and dated,
2 December, 1881 (N° 5272.). The piston, or a part moving therewith carries the
upper carbon in a tubular or other suitable holder, in which holder the carbon is
capable of moving the current being led to it through a flexible coil or spiral. The
carbon is ordinarily held in its holder by a gripping device which only acts when
being raised or held up. When the current is passing all right the gripping device
is held up either by the core of a solenoid which regulates the progressive or feed
movement, or by a separate solenoid or electro magnet, but when the carbons
become so far separated that the current cannot pass, the gripping device becomes
released and allows the upper carbon to descend into contact with the lower one.
The current then passes again and the solenoid or electro magnet raises the gripping
device again and by its means lifts the upper carbon the proper distance for the
predetermined length of arc.
And in order that my said Invention and the manner or performing the same may
be properly understood I hereunto append two sheets of explanatory drawings to
be hereinafter referred to and representing two modifications of my improved lamp.
Figure, 1, on sheet, 1, of the accompanying drawings is a sectional elevation of a
modification of my improved electric arc lamp in which the automatic regulating
details are applied directly upon or in connection with the feed piston, and
figure, 2, is a plan of the gripping device. Figure, 3, on sheet, 2, is a vertical
section of a modification in which most of the regulating details are applied to
other parts. In these drawings the same reference numerals are used to mark the
same or like parts wherever they are repeated.
In the lamp shown in figure, 1, the lower carbon, 4, is held at the lower end of'
a bracket, 5, which has a vertical cylinder, 6, fixed to its upper end; and this
cylinder has working in it a piston, 7, fixed to a tube, 8, which passes through a
stuffing box, 9, at the bottom of the cylinder. The upper carbon, 10, is held in a
clutch, 11, fixed to the bottom of a rod, 12, passing up through the piston tube, 8,
and through an upper tube, 13, fixed to the piston tube by a bracket, 14. The
gradual downward feed movement of the upper carbon, 10, is caused by the
pressure of the piston, 7, on oil or other suitable liquid contained in the cylinder, 6,
and the rate of feed depends on the passage of the liquid from the under to the
upper side of the piston through a passage and port, 15. The upper port of the
passage, 15, is on a vertical face and is formed with an angular tapering notch at
its upper side so that the movement of a small, slide valve, 16, which controls the

page_text: port may act very gradually in opening or closing the port. The valve, 16, which
is kept against the port face by a light spring, 17, bearing against and sliding upon
the inside of the cylinder, is acted on by a vertical rod or wire, 18, fixed to the
iron core, 19, of a solenoid, 20, carried upon the upper tube, 13, the upper end of
the core, 19, being connected to a small bracket by an adjustable spring, 21. The
solenoid, 20, has the current which works the lamp passing through its coils, and
when the action of this current is weakened through increased resistance due to
the distance between the carbon points becoming too great, the weight of the
core, 19, causes the valve, 16, to move downwards and increases the opening into
the passage, 15, and this allows the descent of the piston, 7, to be slightly
accelerated. The reverse action takes place when the distance between the carbon
points becomes reduced, the consequent diminution. in the resistance of the are
causing the action of the solenoid, 20, to be increased so as to lift the core, 19,
and raise the valve, 16, which closes the passage, 15, to a greater or less extent
and diminishes the rate of descent of the piston, 7.
In order that when
the valve, 16, is closed or nearly so, the movement of the piston, 7, may
be stopped notwithstanding possible leakage past the piston or otherwise, the
valve rod, 18, is also connected to a pair of toggle levers or links, 22, connected
to the piston tube, 8, and which when the rod, 18, is raised sufficiently jams a
small block against the inside of the cylinder, 6. In a similar way in
the event of the valve, 16, descending very low through extreme diminution
or absence of the electric current, a reversed pair of toggle levers or links, 23,
jams a small block against the inside of the cylinder and arrests the descent
of the piston, 7. When a new upper carbon, 10, is being put in, the piston, 7, is
by means of its tube, 8, pushed up to the top of its stroke, the liquid above
the piston then passing to the underside of it through a check valve, 24, and
then the upper toggle levers, 23, prevent the piston from descending until the
current is switched on to the lamp. The solenoid, 20, in addition to regulating the
gradual downward feed movement of the upper carbon, 10, also "strikes the arc
or separates the carbon points to the distance for forming the arc, whenever the
current is switched on, the carbons having of course first come into contact. For
this purpose the rod, 18, attached to the core, 19, acts through an adjustable
spring, 25, upon a small lever frame, 26, which is jointed to a piece, 27, formed
upon or fixed to the top of a short holder tube, 28, capable of vertical motion in a
guide, 29, fixed to the bracket, 14, connecting the piston tube, 8, to the upper
tube, 13. The rod, 18, to the lower end of which the carbon holder or clutch, 11,
is fixed can move freely through the holder tube, 28, excepting when the lever
frame, 26, is slightly tilted upwards by the action of the solenoid, and then a small
plate, 30, adjustably fixed on the lever frame grips the rod, 18, and the further
lifting action of the solenoid lifts the rod, 18, and with it the upper carbon, 10, so
as to strike the arc. A small screw, 31, in the piece, 27, prevents the lever
frame, 26, from dropping too far; and a short tube, 32, screwed into the bracket, 14
(or into the top of the piston tube, 8,) serves as an adjustable stop for the drop of
the holder tube, 28, and thereby determines the are distance, as the solenoid with
a given strength of current always, lifts the gripping lever frame, 26, up to the
same point.
In the modification shown in figure, 3, sheet, 2, the parts concerned in the gradual
downward feed movement of the upper carbon, 10, are like those shown and
described in the earlier Specification, hereinbefore referred to; but the solenoid, 20,
forming one of these parts is not also used for striking the arc as in the first modi-
fication herein before described. A second solenoid might be employed but what is
shown in figure, 3, is an electro-magnet, 33, the armature, 34, of which is attached to
the lever frame, 26, of the gripping device. The piston, 7, acts through a rod, 35,
which is attached to a crosshead, 36, movable upon a pair of vertical guide rods, 37, 38.
For the purpose of preventing the piston, 7, crosshead, 36, and other parts from
running down when no current is passing through the coils of the electro magnet, 33,
which is attached to the crosshead, 36, the armature, 34, is connected to one arm, 39,
"

page_text: of a lever which is made with a secord arm, 40, formed as a catch to engage with
ratchet teeth formed on the guide rod, 38, whenever the armaturē is not drawn up
to the magnet.
Having thus particularly described my said Invention and the manner of
performing the same I have to state that I do not restrict myself to, the precise
details herein described or delineated but that what I believe to be novel and original
and claim as the Invention secured to me by and in terms of the herein before in
part recited Letters Patent is :-
1. The combination in an electric arc lamp of a gradual feeding device and an
arc-striking device, the feeding device comprising a solenoid actuated by the lamp
current and acting on a free valve which controls the passage of liquid from under
a piston, and the arc-striking device comprising a solenoid or electro-magnet
operating through a combined gripping and lifting device; the various parts being
constructed and operating substantially as hereinbefore described.
2. The placing of the gradual-feed controlling valve and parts for actuating it
upon or so as to move with the piston of the feed apparatus substantially as
herein before described with reference to figure, 1, of the accompanying drawings.
3. The application of the tuggle-lever or equivalent devices, 22, 23, for preventing
the movement of the feed piston in certain cases substantially as hereinbefore
described.
In Witness whereof, I, the said Andrew Betts Brown, have hereunto set
my hand and seal this sixteenth day of October in the year of our Lord
One thousand eight hundred and eighty-two.
ANDREW BETTS BROWN. (L.S.)