IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1881

page_text: LETTERS PATENT to George Hawkes, of Victoria Chambera, in the City of
Westminster, Gentleman, and Robert Bowman, of Ipswich, in the County of
Suffolk, Mechanic, for an Invention of "IMPROVEMENTS IN ELECTRIC LAMPS."
PROVISIONAL SPECIFICATION left by the said George Hawkes and Robert
Bowman at the Office of the Commissioners of Patents on the 31st May
1881.
GEORGE HAWKES, of Victoria Chambers, in the City of Westminster, Gentleman,
and ROBERT BOWMAN, of Ipswich, in the County of Suffolk, Mechanic. "IMPROVE-
MENTS IN ELECTRIC LAMPS."
In constructing an electric lamp according to our Invention we employ mercury
for the double purpose of forcing the carbon or carbons into juxtaposition and of
making complete connection with the electric current.
The positive carbons are carried in metal standards or sockets, preferably hollow,
the lower ends of which terminate in discs or floats of metal in contact with a
column of mercury contained in a holder, preferably of cylindrical form.
This holder consists of two concentric tubes coramunicating with one another at
their lower ends.
As the positive carbon is consumed the mercury rises in the central tube, forcing
up the carbon and re-establishing the arc. An electro magnet regulates automatically
the adjustment of the carbons by nipping the lower carbon and arresting its ascent
at the required point. Sets of carbons inay be so arranged under this system that
the current may be automatically switched from one set to another, and this
without interfering with the other lights in the same circuit. When several sets
of carbons are employed, the negative carbons are preferably suspended from arms
radiating from a central standard. These negative carbons will be of greater
diameter than the positive carbons, and they may be also supported in holders in
contact with or floated on mercury, so that as the mercury sinks in the outer tube
and rises in the inner tube of the holder, the negative carbon will gradually descend,
and the positive carbons rise to meet them.
More than one carbon can be used as positive or negative, and the light can be
sustained for twenty hours or longer.
By employing lamps of this construction a continuous current of electricity may
be so utilized as to produce one or any given number of brilliant electric lights.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Hawkes and Robert Bowman in the Great Seal Patent Office
on the 30th November 1881.
GEORGE HAWKES, of Victoria Chambers, in the City of Westminster, Gentleman,
and ROBERT BOWMAN, of Ipswich, in the County of Suffolk, Mechanic. "IMPROVE-
MENTS IN ELECTRIC LAMPS."
This Invention relates to the construction of electric lamps of the arc system in
which the lower carbons are buoyed up by mercury, and are checked in their rise
by an oscillating gripping piece operated by an electro magnet.
In Sheet I. of the accompanying Drawings we have shewn our Invention as
applied to an arc lamp fitted with a single pair of carbons; it is however equally
applicable, as will be hereafter explained to lamps provided with two or more pairs
of carbons..
Fig. 1, Sheet I. shews the lamp in partial sectional elevation, and
Fig. 2 is a plan view on an enlarged scale of the same, the upper part of the
lamp being removed.
The frame of the lamp consists of three metal plates A, A1, A2, secured together
by vertical columns, but insulated therefrom. Pendent from the plate A is a metal
tube B which is fitted with a glass lining containing mercury b, in which the lower
carbon holder is immersed. The glass tubular lining is closed at bottom by a metal
plug which presses the glass lining into contact with tho plate A in the act of
securing a fluid-tight junction at the bottom of the tube.
C is the lower carbon and D the upper carbon. The lower carbon C in rising
through an opening in the plate A passes between the arms of an electro magnet Ĕ
fitted to the plate A, and also through a gripping piece F which is pivotted at
right angles to the magnet, and is carried by brackets f secured to the plate A.
Attached to this gripping piece is the armature E' of the magnet E, the attracting
power of which will rock the piece F, and cause it to grip the carbon C.
So soon however as the arinature is released the carbon C will be free to rise
under the pressure of the mercury which is however controlled by a kind of porous
piston c attached to the carbon holder C₁, and fitting the glass lining of the tubo B.
This piston may consist of wash leather, as indicated in the Drawing, or it may
be a cup leather piston pierced with a fine hole to permit of the slow passage of the
mercury through it.
The plate A of the frame is pierced centrally to allow the carbon C to pass
upwards through it, and it serves also to cover the electro magnet E and the parts
in connection therewith.
The carbon D is fitted in the socket at the end of a rod D' pendent from the
cross bar of an electro magnet G. This magnet is supported by brackets g affixed
to the plate A², and underlying its poles is an armature G' made fast to the pendent
rod D¹. When the lamp is not in action the carbons C and D will be in contact
with each other, the latter being pressed down by means of a coiled spring D*, but
so soon as a current is passed through the lamp, the electro magnet Ġ will attract
its armaturo, and thereby lift the carbon D from the carbon C to establish the arc.
On the arrest of this current the carbon D will fall and be held firmly against the
carbon C by means of the coiled spring D².
The terminal wires of the magnet G are connected the one through the plate A³
with the carbon D, and the other through one of the pillars of the lamp fraine with
one pole of the electric generator by a wire 1.
In order to cause the electro magnet E to regulute the carbon C with great
accuracy we adopt the following contrivance:-H is an electro-magnet placed

page_text: within the circuit, one of its wires leading to the electric generator, and the other
to the plate A in metallic connection with the lower carbon holder. Opposed to
this electro magnet H is an electro magnet H', between which oscillates an
armature I.
The electro magnet H connects with the electro magnet E before mentioned, and
is intended to impart rapidly intermittent currents thereto, for the purpose of
enabling it to actuate the oscillating gripper F, and allow the carbon C to rise
gradually at an almost imperceptible rate.
To this end one terminal of the electro magnet E is connected to the plate A of
the lamp, and through it with the wire 2 from the electric generator and the other
terminal of this magnet connects with one terminal of the magnet H. By means
of a coil of wire the oscillating armature I is brought into connection with the
second terminal of the electro magnet H'. An extension of this armature I bears
against a fixed stop I' connected by a wire to the wire 1 leading to the electric
generator. This takes place when the armature is attracted by the electro
magnet H, as shewn in the Drawing, but as the resistance in the main circuit
increases by the lengthening of the arc, a larger proportion of the current will pass
by the branch circuit through the magnet H₁, thereby increasing the attractive
power of that magnet, and at the same time diminishing the attractive force of the
magnet H. So soon as the magnet H¹ overpowers the magnet H, the armature I
will be drawn to the dotted position, and the magnets E and H' will be thrown
out of circuit.
This will release the carbon C from the gripper F, and leave it free to rise by its
own buoyancy; it will however be instantly checked by reason of the magnet H
again attracting the armature I and closing the branch circuit.
The electro magnet E being now again efficient will attract its armature and
cause the carbon C to be gripped as before. By a succession of these movements
the carbon C will be maintained at a proper distance from the carbon D.
To ensure a greater delicacy of adjustment of the carbon C, we propose to couple
up the oscillating armature I and the fixed stop 1', inserting between them a rotary
contact breaker, as at K, of any approved construction. This contact breaker may
be driven by clock work, or by a band from a motive power engine. The effect of
this contact breaker will be to subdivide the intervals of rest of the electro
magnet E, and thereby to produco a minute division of the step by step movement
of the lower carbon.
Sheet II. of the Drawings illustrates the Invention as adapted to arc lamps
having two pairs of carbons. Fig. 3 is a sectional elevation of this lamp. The
same letters of reference being used for the like parts in Sheet I., no further
description of these parts will be required. C and C* are the lower carbons, their
holders being immersed in mercury, as before explained, to give them a tendency
to rise when released from their gripping picces F, F*, which are both made fast
to the armature of the electro-magnet E, and consequently come into action
simultaneously.
The holder of each carbon is notched to receive the edge of a horizontal rocking
bar L (as seen best in the detached plan view, Fig. 4) mounted on a support L¹
standing up from the plate on which the armaturo E is pivotted.
The notch of the holder of the carbon C is made near the bottom thereof and
aunular for convenience, and the notch in the holder of the carbon C* is made near
the top of that holder. On starting the lamp the carbon C* which is the reserve
carbon, is held down out of use by means of the bar L which is inserted in the
notch of its holder. A tendency is given to this bar to By out of the notch by
reason of a coiled spring L² which is restrained from acting by reason of the opposite
end of the bar bearing against the holder of the carbon C. So soon however as this
holder has risen sufficiently high to bring its notch into coincidence with the edge
of the rocking bar L, the spring L will come into action and release the bar from
the notch in the holder of the carbon C, as shown by dots in the plan view, Fig. 4.
The carbon C will then be free to rise and establish an arc with the carbon D*,

page_text: the carbons C and D gradually dropping out of use. Fig. 5, Sheet III. shews in
diagram an arrangement for putting two or more lamps in a divided circuit, and
the means of connecting up the same. When the lamps are connected up this way,
we propose to use the magnets H and H¹ (Fig. 1), but when the lamps are put in
series, we should use the magnet H' alone, and apply a spring for holding the
armature I in contact with the fixed stud I. When the resistance in the main
circuit has increased to the regulating point, the magnet H' will have sufficient
power to break the subcircuit, and adjust the carbons, as before described.
Fig. 6, Sheet IV. shews the means of putting five or more lamps in series, the
figures 3, 3, 3, 3, 3, represent the regulators in the subcircuit.
Fig. 7, Sheet IV. shews "shunts" in the circuit for extinguishing ono light
without putting out the others.
Fig. 8, Sheet IV. shews an economical way of connecting a great number of
lamps to one machine, both in a divided circuit and in series. Numbers 1, 2, 3, 4,
shew lamps put in series, and numbers 5, 6, 7, 8, lamps put in a divided circuit.
Having now set forth the nature of our "Invention of Improvements in Electric
Lamps," and explained the manner of carrying the same into effect, we wish it to
be understood that under the above in part recited Letters Patent, we claim,―
First. The means above described with reference to Sheet I., of the Drawings for
regulating tho feed of floating carbons.
Second. The means described with reference to Sheet II. of the Drawings for
automatically bringing a fresh pair of carbons into the circuit.
In witness whereof, I, the said George Hawkes, have hereunto set my hand
and seal, the Thirtieth day of November, in the year of our Lord One
thousand eight hundred and eighty one.
ASANAD