IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1880

page_text: LETTERS PATENT to Killingworth William Hedges, of No. 25, Queen Anne's
Gate, Westminster, in the County of Middlesex, for an Invention of
IMPROVEMENTS IN ELECTRIC LAMPS."
26
PROVISIONAL SPECIFICATION left by the said Killingworth William
Hedges at the Office of the Commissioners of Patents on the 30th November
1880.
KILLINGWORTH WILLIAM HEDGES, of No. 25, Queen Anne's Gate, Westminster,
in the County of Middlesex. "IMPROVEMENTS IN ELECTRIC LAMPS."
In the Specifications of Patents granted to me on the 8th January 1879, No. 81,
and the 8th March 1879, No. 925, I described several constructions of electric lamps, in
which the carbons or some of them as they became consumed descended by gravity
along inclined tubes, their descent beyond a suitable point being arrested either by
their abutting on a block of refractory material or by subjecting them to such
increase of friction in their tubes as to overcome the force of gravity impelling
them downwards. Part of my present Invention relates to the construction of
electric lamps with inclined carbons so arranged that I dispense with the refractory
abutment, and also with the means which I formerly described of arresting the
descent of the carbons by friction. For this purpose I employ in each lamp three
carbons; two of these, constituting together the positive electrode, lie in open troughs
inclined to one another and to the horizontal, so that the two carbons tending to
descend by gravity along their respective troughs meet at their points, remaining
always in contact butting against each other, notwithstanding the consumption of
their lower ends. The third carbon, constituting the negative electrode, also lies in
an inclined trough, descending along it as it is consumed, and butting against a small
stop near its point, which stop permits its descent only according as the portion of
the carbon against which the stop bears becomes wasted away. The three troughs
are arranged with a moderate slope just sufficient to ensure the downward slide of
the carbons. Electrical contact is made with each carbon by means of a piece of
hollowed metal lying on the carbon near the lower end of its trough, this piece of
metal having a long conducting arm hinged to the trough at a higher point. In order
Prins Gr

page_text: to determine and adjust the distance between the point of the negative carbon and
the meeting point of the two positive carbons, in which distance the voltaic arc is
presented, I mount the trough containing the negative carbon so that it can move
horizontally towards or away from those containing the positive carbons, and I
connect it to the armature of an electro magnet or to the core of a solenoid coil in
the lamp circuit. When the lamp is inert the end of the negative carbon is brought
in contact with the meeting of the positive carbons by a weight or spring, and the
lamp being then put in circuit the electricity passing through the carbons and also
through the coil of the electromagnet or solenoid, the armature or core is attracted,
and a movement is thus given to the trough of the negative carbon, withdrawing
it from the positive carbons, and so establishing the voltaic arc.
The troughs
containing the positive carbons, which are connected together by rigid framing,
may thus be moved by the action of the electromagnet or solenoid, the trough of
the negative carbon remaining stationary; or both may be so moved, as may be
readily understood. According to another part of my Invention I construct an
electric lamp, in which the illumination is produced by incandescent carbon in the
following manner :-To a metal disc I secure a deep basin glass, suspending it from
the edge of the disc by means of a caoutchouc ring, which can be pressed by a screw
flange so as to bear tightly against the circumference of the basin. From the centre
of the disc a tube extends upwards, this tube containing a sliding weight of non
conducting material, which presses on the end of the carbon rod. The carbon rod
passes through a non conducting socket at the lower end of the tube, and rests by
its end on the periphery of a chisel edged metal disc, which is mounted on a con-
ducting stem projecting down from the disc but insulated therefrom. I make this
stem with a joint, so that the lower part which carries the chisel edged disc can be
turned aside when a carbon has to be inserted into the tube, and can be turned
back so as to provide the support for the lower end of the carbon. On another
stem projecting down from the disc I mount a bent lever loaded at one end with
an adjustable weight, which causes the other end to press against the side of the
carbon a little above the lower end of the carbon, making contact therewith.
The chisel edged disc being in such a position that the carbon bears on its periphery
a little on one side of a vertical line through the centre of the disc, the loaded lever
bearing against the carbon on the same side of the vertical line does not tend to
push the carbon off the disc. When the two stems above mentioned are connected
in an electrical circuit the electricity passing from the one stem through the loaded
lever into the carbon and from the carbon through the metal disc and the other
stem, the carbon becomes incandescent. In order to provide against accident in
case of an explosive gaseous mixture being ignited within the glass, I arrange on
the disc a light safety valve which will open to allow of escape when undue
pressure is produced.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Killingworth William Hedges in the Great Seal Patent Office on
the 28th May 1881.
KILLINGWORTH WILLIAM HEDGES, of No. 25, Queen Anne's Gate, Westminster,
in the County of Middlesex. " IMPROVEMENTS IN ELECTRIC LAMPS."
In the Specifications of Patents granted to me on the 8th January 1879, No. 81,
and the 8th March 1879, No. 925, I described several constructions of electric
lamps in which the carbons or some of them as they became consumed descended
by gravity along inclined tubes, their descent beyond a suitable point being
arrested either by their abutting on a block of refractory material, or by sub-
jecting them to such increase of friction in their tubes as to overcome the force
of gravity impelling them downwards. Part of my present Invention relates to the
construction of electric lamps with inclined carbons so arranged that I dispense with
with the refractory abutment; and also with the means which I formerly described
of arresting the descent of the carbons by friction. For this purpose I employ in
each lamp three carbons; two of these, constituting together the positive electrode,
lie in open troughs inclined to one another and to the horizontal, so that the two
carbons tending to descend by gravity along their respective troughs meet at their
points, remaining always in contact butting against each other, notwithstanding
the consumption of their lower ends. The third carbon constituting the negative
electrode also lies in an inclined trough, descending along it as it is consumed, and
butting against a small stop near its point, which stop permits its descent only
according as the portion of the carbon against which the stop bears becomes wasted
away. The three troughs are arranged with a moderate slope just sufficient to
ensure the downward slide of the carbons. Electrical contact is made with each
carbon by means of a piece of hollowed metal lying on the carbon near the lower
end of its trough, this piece of metal having a long conducting arm hinged to the
trough at a higher point. In order to determine and adjust the distance between
the point of the negative carbon and the meeting point of the two positive carbons,
in which distance the voltaic arc is presented, I mount the trough containing the
negative carbon so that it can move horizontally towards or away from those
containing the positive carbons, and I connect it to the armature of an electro
magnet, or to the core of a solenoid coil in the lamp circuit. When the lamp is
inert the end of the negative carbon is brought in contact with the meeting of the
positive carbons by a weight or spring, and the lamp being then put in circuit the
electricity passing through the carbons, and also through the coil of the electro
magnet or solenoid, the armature or core is attracted, and a movement is thus given
to the trough of the negative carbon, withdrawing it from the positive carbons, and
so establishing the voltaic arc. The troughs containing the positive carbons, which
are connected together by rigid framing, may thus be moved by the action of the
electro magnet or solenoid, the trough of the negative carbon remaining stationary,
or both may be so moved, as may be readily understood.
According to another part of my Invention I construct an electric lamp in which
the illumination is produced by incandescent carbon in the following manner :-
To a metal disc I secure a deep basin glass, suspending it from the edge of the disc
by means of a caoutchouc ring, which can be pressed by a screw flange so as to
bear tightly against the circumference of the basin. From the centre of the disc
a tube extends upwards, this tube containing a sliding weight non conducting
material in which presses on the end of the carbon rod. The carbon rod passes
through a non-conducting socket at the lower end of the tube, and rests by its end

page_text: on the periphery of a chisel edged metal disc which is mounted on a conducting
stem projecting down from the disc, but insulated. therefrom. I make this stem
with a joint so that the lower part which carries the chisel edged disc. can be
turned aside when a carbon has to be inserted into the tube, and can be turned
back so as to provide the support for the lower end of the carbon. On another
stem projecting down from the disc I mount a bent lever loaded at one end with
an adjustable weight, which causes the other end to press against the side of the
carbon a little above the lower end of the carbon, making contact therewith. The
chisel edged disc being in such a position that the carbon bears on its periphery
a little on one side of a vertical line through the centre of the disc, the loaded lever
bearing against the carbon on the same side of the vertical line docs not tend to
push the carbon off the disc. When the two stems above mentioned are connected
in an electrical circuit, the electricity passing from the one stem through the loaded
lever into the carbon, and from the carbon through the metal disc and the other
stem, the carbon becomes incandescent. In order to provide against accident in
case of an explosive gaseous mixture being ignited within the glass, I arrange on
the disc a light safety valve which will open to allow of escape when undue
pressure is produced
Fig. 1 is a front view of an electric lamp according to my Invention, and Fig. 2
is a side view of the pair of positive carbons. A is the negative carbon lying in
an inclined trough or open tube, and butting near its end against an adjustable
stop a, so that the carbon descends as that portion of it against which a bears
becomes consumed. Instead of placing the stop a on the underside of the carbon,
as shewn in Fig. 1, it may be placed at the side, as shewn at a¹, Fig. 3, which is a
part side view of the negative carbon. Instead of a metallic stop, a rod a² of
steatite or other refractory material may be employed, as in the part side view,
Fig. 4. The positive carbons B and C meet together at their ends, as shewn in
Fig. 2, and one of these may be smaller than the other, so that the whole of the
electrical current may pass through the larger, the smaller carbon becoming
gradually consumed with it. The contacts for both the negative, carbon A and
the larger B of the positive carbons are made by pieces of metal D slightly
hollowed to fit over the carbons, and hinged at higher points & to the troughs in
which the carbons lie, the current being led to and from the contact pieces D by
wires d¹ escaping the joints of their hinges. The trough in which the carbon A
lies is suspended by radius rods E, E, from the upper framing F of the lamp to
which the troughs for the carbons B and C are fixed. In the framing F is arranged
an electro magnet G having its coil in the lamp circuit, its armature g is attached
to one of the radius rods E with a screw adjustment. When the lamp is out of
circuit the end of the carbon A butts against the meeting of the carbons B and C,
but when an electric current is passed through the lamp, kindling the carbons
where they butt, the electro magnet G becomes excited and attracts its armature g,
whereby the end of the carbon A becomes separated from B and C, and the arc is
established between them. As the carbons become consumed the two B and C
continue to descend their respective troughs, the end of each supporting the other,
and the carbon A. advances, as permitted by the stop a, so as to present its end at
nearly the same distance from the ends of B and C. In order to render the stop a
effective, an abutment screw a³ is provided at the upper side of the carbon A.
According to a modified arrangement, shewn in Fig. 5, the trough holding the
carbon A is suspended from one pivot and attached to the core of a solenoid H.
This core may carry at its end the armature of an electro magnet M having a coil
of high resistance in a by-pass circuit, so that when the resistance of the arc of the
lamp becomes excessive the core shall be attracted back, causing the carbons to

page_text: approach. The stop a for the negative carbon may, as shewn in Fig. 5, consist of
several screws in a ring encircling the carbon, each of these screws being adjustable
to suit the shape which the end of the carbon assumes as it is consumed.
When alternating electrical currents are employed a single carbon B butting
against a stop b may be used, as shewn in Fig. 6, instead of the two carbons
and C, described with reference to Fig. 2. In this case both the carbons slide
down inclined troughs, and are supported by stops near their ends, as described.
Fig. 7 is a vertical section of an incandescent electric lamp according to my
Invention. To the metal disc A I secure the basin glass B, suspending it from the
edge of the disc by means of a caoutchouc ring b which is compressed by the
screw flange a. From the centre of the disc A extends the tube C containing
the sliding weight D, which has a piece of insulating material bearing on the top of
the carbon rod E. This rod guided through a socket c at the bottom of the tube
rests by its end on the periphery of the chisel edged metal disc F, a little on one
side of the vertical central line thereof, and the carbon rod is pressed on laterally by
the bent lever G loaded by the adjustable weight g. The stem which carries the
disc F is jointed at f with a pin working in a slot, so that the lower part of the
stem carrying the disc can be turned aside out of the centre line of the lamp
when a fresh carbon has to be introduced. The electricity led to and from the
posts H and K in passing through the part of the carbon rod between its end and
the point where the lever G presses on it is heated to incandescence and gives
light. A lamp thus arranged may be used without a glass, as shewn by the
vertical section Fig. 8, and plan Fig. 9, in which Figures the parts corresponding
with those described with reference to Fig. 7 are marked with similar letters.
Fig. 10 is a part section, and Fig. 11 a plan shewing the disc A which forms the
cover of the lamp, provided with a safety valve in case of explosion of combustible
gas produced within the glass. This safety valve consists of an annulus L of very
thin metal which is held in a recess in the cover A by an inner ring held down
by setting screws and by an outer ring m which bears it down by its weight.
Should the gaseous mixture within the lamp glass explode, the thin metal Lis
driven up, or rent, or crumpled, thus saving the glass from being broken. I find
that such explosions may generally be prevented from occurring by introducing
into the lamp glass a little ammonia or other volatile substance, the vapour of
which will prevent the formation of combustible gas.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim,—
First. The construction of electric lamp in which the positive electrode consists
of two carbons lying in inclined troughs in which they can descend by gravity so
that their ends always butt against each other, and the negative electrode consists
of a carbon also lying in an inclined trough and butting against a stop, the trough
of the negative carbon being moveable so that the distance between it and the
positive carbon can be varied by automatic regulating apparatus, substantially as
herein described.
Second. In an electric lamp of the kind referred to in the preceding claim
conducting the electricity to and from the carbon by means of a piece of hollowed
metal lying on the carbon, and having a conducting arm hinged at a higher point
to the carbon trough, substantially as herein described.
Third. In an electric lamp in which the illumination is produced by incandescence
of a carbon rod the combination of the single guide tube C with its sliding weight D,
the carbon rod E, the disc F mounted on a jointed stem, and the loaded bent lever G,
as herein described with reference to Figs. 7, 8, and 9 of the accompanying
Drawings.
Fourth. In an incandescent lamp securing the basin glass to the upper disc by
means of a caoutchouc ring forced against the periphery of the glass by a
compressing screw flange, substantially as herein described.
Fifth. In an incandescent lamp providing the cover with a safety valve
I

page_text: consisting of a thin metal annulus, substantially as and for the purpose herein set
forth with reference to Figs. 10 and 11 of the accompanying Drawings.
In witness whereof, I, the said Killingworth William Hedges, have hereunto
set my hand and seal, this Twenty eighth day of May, in the year of our
Lord One thousand eight hundred and eighty one.
KILLINGWORTH W. HEDGES. (L.S.)