IMPROVEMENTS IN APPARATUS FOR PRODUCING THE ELECTRIC LIGHT
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Edward John Cowling Welch at the
Office of the Commissioners of Patents on the 19th November 1878.
EDWARD JOHN COWLING WELCH, of Manchester; in the County of Lancaster,
Engineer. "IMPROVEMENTS IN APPARATUS FOR PRODUCING THE ELECTRIC LIGHT."
My Invention has for its object to regulate the intensity of the currents in
electric lamps or in apparatus for producing the electric light. To this end I mount
wires, rods, or pencils of platinum, iridium, carbon, plumbago, or other suitable
metal or material so that the lengths of such wires, rods, or pencils extending
between parts of greater conducting capacity can be regulated either by hand or by
automatic means, whereby greater or less resistance is introduced into the circuit
as may be required either to regulate the intensity of the light or to prevent the
overheating or fusion of the said wires, rods, or pencils. The arrangements adopted
when carrying my Invention into effect may be greatly varied. In one arrange-
inent a wire, rod, or pencil, say, for example, a pencil of carbon, is supported or held
by one end in a fixed socket or clip. The other end of the pencil or an intermediate
part thereof is embraced by a sleeve or clip in such a manner as that there may be
electrical contact at the same time that the said sleeve or clip can be freely slid upon
the pencil. The position of the said sleeve or clip upon the said pencil is adjustable
with relation to the fixed socket or clip. To effect the automatic adjustment I
employ an electro-magnet acting upon an armature which is connected with the
said sleeve or clip in such a manner as that as the current increases in intensity the
armature by approaching nearer to the magnet increases the distance between the
fixed socket or clip and the inovable sleeve or clip. The armature may be formed
or fixed upon a spring lever or upon a lever which is acted upon by a spring or by
springs so that the resistance is increased as the armature approaches the magnet.
The current is passed through the coils of the magnet and through the said pencil
from the fixed socket or clip to the movable sleeve or clip or vice versa. The socket
in which the pencil is fixed may be formed in or fixed to a part which is fitted to
slide or move.and is connected with the said armature, the pencil sliding in electrical
contact with a fixed part or conductor. A coil, or bar, or arrangement of parts acting
0

page_text: by expansion and contraction may be used in lieu of the electro magnet and arma-
ture if considered or found to be effective and suitable. In some cases the
adjustment may be effected by sliding or moving one of the conductors which are
in contact with the pencil. Two or more pencils, wires, or rods may be mounted
in one apparatus. A riband of metal or substance or any other suitable form of
material may be used in place of the said wire or pencil. The arrangement may be
varied by connecting the pencil, wire, or rod with fixed supports and employing a
movable contact spring or part which is in the electrical circuit so that the current
flows only through a part of the pencil or wire extending from this movable conductor
to one of the fixed supports, or the wire or riband may pass around or partly around
a wheel or pulley which constitutes one of the conductors, the said wheel or the
other conductor being movable. If preferred for any reason both supports or con-
ductors may be arranged to move, and other variations may be made so long as the
adjustment of the length of the portion of the wire, rod, pencil, or part which is to
furnish the light is effected by increasing or decreasing the distance between the
conductors with which such wire, rod, pencil, or part is in electrical contact.