IMPROVE- MENTS IN ELECTRIC LAMPS
Year: 1879

page_text: LETTERS PATENT to Killingworth William Hedges, of No. 25, Queen Anne's
Gate, Westminster, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN ELECTRIC LAMPS."
Sealed the 4th April 1879, and dated the 8th January 1879.
PROVISIONAL SPECIFICATION left by the said Killingworth William Hedges
at the Office of the Commissioners of Patents on the 8th January 1879.
KILLINGWORTH WILLIAM HEDGES, of No. 25, Queen Anne's Gate, Westminster,
in the County of Middlesex. "IMPROVEMENTS IN ELECTRIC LAMPS."
My Invention relates to that kind of electric lamp in which two carbons descending
as they waste along tubes or guides rest by their lower ends on a piece of refractory
material, the luminous are being formed on the face of the said material, between
the ends of the carbons which nearly meet thereon. The object of my Invention is
to provide for lamps of this kind menus of automatically regulating the distance
between the ends of the carbons, according to the strength of the electric current.
For this purpose I mount the guide for one of the carbons on a transverse axis so
that it can be made to rock thereɔn, and I provide an adjustable spring or weight
which presses it in one direction, namely, that which causes the lower end of the
carbon guided by it to approach the other carbon. I also provide an electro-magnet
and connect its armature to the said guide, and I put the coil of the electro-magnet
in the circuit of the carbons; the magnet and its armature being so arranged that
when a strong current of electricity passes through the coil of the former the arma-
ture is attracted in opposition to the adjustable weight or spring above mentioned
and the one carbou is thus withdrawn from the other. As the force with which the
armature is attracted depends on the strength of current passing through the coil of
the electromagnet the distance separating the carbon points is thus regulated auto-
matically according to the force of the electric current passing through them, the

page_text: distance being increased by the greater attractive force on the armature when the
electricity is increased, and being diminished by the superior force of the weight or
spring when the electricity is diminished. Instead of employing an electromagnet
and armature for the purpose above stated a coil and plunger or removeable core of
iron may be employed, the core being drawn into the heart of the coil when it is
strongly excited and being withdrawn therefrom by the weight or spring when the
electrical force in the coil is sufficiently lessened. The one carbon with its guide
which is adjusted as above described may be vertical or nearly so, the other carbon
with its guide lying in an inclined attitude, or both carbons and guides may be
inclined.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Killingworth William Helges in the Great Seal Patent Office on the 7th
July 1879.
KILLINGWORTH William HedgES, of No. 25, Queen Anne's Gate, Westminster, in
the County of Middlesex. "IMPROVEMENTS IN ELECTRIC LAMPS."
My Invention relates to that kind of electric-lamp in which two carbons des-
cending as they waste along tubes or guides rest by their lower ends on a piece of
refractory material, the luminous are being formed on the face of the said material
between the ends of the carbons which nearly meet thereon. Tue object of my
Invention is to provide for lamps of this kind means of automatically regulating
the distance between the ends of the carbons according to the strength of the
electric current. For this purpose I mount the guide for one of the carbons on a
transverse nxis so that it can be made to rock thereon, and I provide an adjustible
spring or weight which presses it in one direction, namely, that which causes the
lower end of the carbon guided by it to approach the other carbon. I also provide
an electro-magnet and connect its armature to the said guide, and I put the coil of
the electro-magnet in the circuit of the carbons, the magnet and its armature
being so arranged that when a strong current of electricity passes through the coil
of the former, the armature is attracted in opposition to the adjustible weight or
spring above mentioned, and the one carbon is thus withdrawn from the other.
As the force with which the armature is attracted depends on the strength of cur-
rent passing through the coil of the electro-magnet, the distance separating the
_carbon points is thus regulated automatically according to the force of the electric
current passing through. them, the distance being increased by the greater attrac
tive force on the armature when the electricity is increased, and being diminished
by the superior force of the weight or spring when the electricity is diminished.
Instead of employing an electro-magnet and armature for the purpose above stated,
a coil and plunger or moveable core of iron may be employed, the core being drawn
into the heart of the coil when it is strongly excited, and being withdrawn there-
from by the weight or spring when the electrical force in the coil is sufficiently
lessened. The one carbon with its guide which is adjusted as above described
may be vertical, or nearly so, the other carbon with its guide lying in an incline.
attitude, or both carbons and guides may be inclined.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 represents the side view of an electric lamp according to my Invention,
and Fig. 6 the side view of a molified construction thereof. A and B are the two
carbons, the one vertical and the other inclined, both free to slide in guides so
that their lower ends rest near each other on a block C of refractory material, such
as fire clay. This block may be sloped as shewn in the side view thereof, Fig 2,
when it is desired to reflect the light principally in one direction. In one of the
carbons BI introduce a core b of chalk or other calcareous substance, which may
either be central in the carbon as shewn in Fig. 1, or it may merely be laid in a
groove formed on the upper side of the carbon. This material fuses at the meeting
ends of the carbons forming there a body of fused material which protects the face
of the block C from waste and becomes dissipated in vapour as it is supplied by
its advance along with the carbon. The block C, instead of being stationary ns
shewn in Fig. 1, may be made moveable so as to present fresh portions of its sur-
face successively to the voltaic are at the ends of the carbons.
For this purpose I
make the refractory material in form of a disc as shewn in Fig. 3, and place it in
a socket at the end of an axis c which I cause to rotate slowly by clockwork or
other suitable motor. Or the refractory material may be made in the form of a
cylinder, as shewn in Fig. 4, caused to revolve slowly or to have both a rotary and

page_text: a longitudinal motion. The refractory material may be kept cool by water cir-
culating through a hollow block supporting it, as shewn in Figs. 5 and 6. The
guide of the carbon A is mounted on a pivot or transverse axis a, and it carries an
arinature D facing the pole of an electro-magnet E, the coil of which is in the lamp
circuit. When by the formation of the voltaic arc between the lower ends of the
carbons a considerable current of electricity passes through the coil of E, the arma-
ture D is attracted towards E, and the movement thus imparted to the guide of A
withdraws its lower end from B. When the distance between the ends of A and
B is so great as to diminish or arrest the electric current, then the electro-magnet
E exerting less attraction on the armature D, a spring d pressing on the guide
causes the lower end of A to approach B. Thus the distance of the ends of the
carbons is automatically regulated by the force of the electric current. The guide
of the other carbon B may also be pivotted as shewn with a spring drawing it
against a fixed spot, so that at any time it can be moved in case of adhesion of the
end of the carbon to fused material on the surface of C. The movable guide of A
instead of being mounted on a pivot may be arranged to have a parallel motion
as shewn in Fig. 7, and connected to an iron core F that can move within a solenoid
coil G in the lump circuit, a spring forcing the core F in a direction out of the
coil when the current through G is too feeble. It is of advantage to provide in
the guide of the inclined carbon B small rollers H to reduce friction, so that the
carbon can freely advance along the guide as it end becomes wasted. Small
rollers K are also placed with advantage near the end of the upright guide of A,
these rollers having their axes working in inclined slots so that they tend to hold
the carbon with a certain grip.
Having thus described the nature of the said Invention and in what manner the
same is to be performed, I would have it understood that I make no general claim
to the arrangement in an electric lamp of two carbons inclined towards one another
with their lower ends meeting, but I claim in respect of an electric lamp in which
the carbons are so arranged, making one of the carbon guides moveable and acting
on it by an electro-magnet, having its coil in the lamp circuit so as to effect the
automatic adjustment of the distance of the carbons according to the force of the
electric current, substantially as described.
In witness whereof, I, the said Killingworth William Hedges, have hereunto
set my hand and seal, this Fifth day of July, in the year of our Lord One
thousand eight hundred and seventy-nine.
KILLWTH. WM. HEDGES. (L.S.)