IMPROVEMENTS IN ELECTRIC LAMPS OR LIGHTING APPARATUS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the Office
of the Commissioners of Patents on the 4th August 1883. Communicated
to him from abroad by La Societé F. Girard et Cio, of Paris, France.
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, and Co, Patent Agonts,
Southampton Buildings, London, "IMPROVEMENTS IN ELECTRIC LAMPS OR
LIGHTING APPARATUS [A communication to him from abroad by La Socicté
F. Girard et C, of Paris, France.]
"
This invention relates to electric lamps or lighting apparatus of that class in
which an electro-magnet excited by a current through a shunt or derived circuit is
employed for causing the approximation of the carbons. The improved mechanism
which I employ for advancing the upper carbon towards the lower carbon is very
simple and the regulation is extremely easy.
The improved apparatus moreover, comprises a safety device for automatically
preventing any abnormal rupture of the circuit. The coil for causing the continuous
forward movement of the upper carbon is provided with a resistance coil designed
to avoid the production of sparks at the contacts by which the derived current
passes out of the regulator.
The current enters the lamp by means of one of the posts of the lamp-framo
and passes through a thick wire of an electro-magnet designed to produce the
automatic formation of the arc by the attraction of its armature.
During the normal operation of the lamp the current passes upward through the
two carbons; but if, by reason of the consumption of the carbons, the resistance at
the are becomes too great, the current through a shunt or derived circuit, which
passes through the coil of another electro-magnet, will augment in intensity and
cause the armature of the said magnet to be attracted, thereby actuating a lever
and causing the upper carbon to descend. This lever has a click or pawl which
acts upon a toothed wheel thereby transmitting movement to a roller. The
movement of this lover may be regulated by a spring.
Each attraction of the said armature tends to produce a spark at two contacts,
but this inconvenience is obviated by interposing in the derived circuit a resistance-
coil, whereby the current will not be completely interrupted at each attraction of
the armature.

page_text: If the upper carbon should be subjected to an abnormal amount of wear, or
become fractured, the approximation of the carbons can still be obtained by a
safety device hereinafter described.
but
During the normal separation of the carbons, two contacts are separated;
when, by reason of a fracture of the upper carbon, the current between the two
carbons is completely interrupted, an armature being more strongly attracted by
the first electro-magnet, the elasticity of a spring will cause it to rise drawing
with it one of tho said contacts. The latter coming against two contacts, the
current finds a path through a wire to a safety coil. This coil is provided at its
interior with a soft iron core which, magnetized by the passage of the current,
attracts a pivotted armature thereby drawing two rollers away from the upper
carbon (or carbon-holder) which can then descend by gravity and approach the
lower carbon. A resistance-coil can also be placed in the circuit connecting the
safety coil to the side of the casing which communicates with the negative polo.