IMPROVEMENTS IN ELECTRIC LIGHTING APPARATUS
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the Office of
the Commissioners of Patents on the 13th August 1879. A communication
from abroad by Doctor Luigi Concornotti, of Crémone, Italy.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, and Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN ELECTRIC LIGHTING
APPARATUS." [A. communication from abroad by Doctor Luigi Concornotti, of
Crémone, Italy.
This Invention relates to improved apparatus for developing electric light, and is
carried into practice as follows, that is to say :-I provide two metallic rods which
are connected with the two wires of the circuit, within which the apparatus or
lamp is situated. In one form of the said improved apparatus, these rods are placed
in such a position that they rise vertically from a socket or base, and in another
form they are led from a ring downward; but in both forms of the said apparatus
the rods are parallel to and insulated from each other, and the free end of each one
is fork-shaped, rollers being pivotted within the forks. These rollers may be of
platina, steel, or copper, and are so arranged as to be exchanged when required.
Instead of the said metallic rollers, I may use carbon rollers, which must however
be of much greater diameter than the metallic rollers. A bar or rod of carbon rests
upon a portion of the periphery of the two rollers, and descends as it is consumed.
This bar or rod is preferably made concavo-concave or double concave in transverse
section, experience having demonstrated that this form ensures the best results.
The contact between this carbon bar and the two rollers is at first only along two
very narrow zones corresponding to the geometrical generating lines. During the
passage of the current this contact is, so to speak, no longer absolute by reason of
the repulsions of the contiguous elements of one single current. The result is that
two very small voltaic arcs are formed, whilst the portion of the carbon interposed
between these arcs becomes incandescent.
The other extremity of the said carbon bar is furnished with insulating material
of any suitable kind, and is held by a holder formed with nippers attached to a
prismatic socket or bush, which embraces a guide of the same form in transverse
section, and slides with little friction along the said guide. In one form of the said
improved apparatus, the prismatic guide is fixed vertically upon the base to which
the electrodes are attached. In another form of the apparatus the said guide is
fixed to the cover. The carbon bar as it is consumed is compelled to descend by
its gravity, and is guided in this downward movement by the socket or bush around
the guide.

page_text: The electrodes, carbon, carbon-holder, and the guides, may be enclosed within a
globe or cylinder or in a covering of any other form made of glass or mica, this
being for the purpose of preventing or reducing the consumption of carbon.
Naturally that form of covering will be preferred, which is of the smallest
dimensions. In one form of the said improved apparatus, the glass or other
covering is mounted upon the base or socket in such a manner as to close the only
opening, and form a hermetically-closed chamber. In another form of the said
apparatus the said glass or other covering is applied to a ring hereinbefore
mentioned, which is situated towards the upper part of the apparatus, and from
which the electrodes lead downward. This ring is provided with a cover which
closes the chamber containing the carbon, as tightly as is done in the first named
form of the apparatus.
A spring valve is provided in the base of the apparatus when constructed
according to the first named form, and in the cover when the apparatus is con-
structed according to the other form. The object of this valve is to prevent any
inconveniences which might otherwise arise by reason of a difference between the
interior and exterior pressures.