IMPROVEMENTS IN ELECTRIC LAMPS
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the Office
of the Commissioners of Patents on the 16th December 1878. A communica-
tion from abroad by Léon Regnard, of Paris, France.
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN ELECTRIC LAMPS." [A communication from
abroad by Léon Regnard, of Paris, France.]
This Invention relates to improvements in electric lamps or regulators, whereby
carbon sticks of any length may be used. The carbon holders where the current
enters the carbons are at a constant distance from the points, and the carbons
are maintained at an invariable or almost invariable distance apart. These results
are obtained by the employment of carbon sticks, shaped or moulded in the form
of a screw, rack, or other mechanical movement (instead of a plain rod as in
ordinary electric light regulators) and by making the carbons themselves form
part of the trains of mechanism by which their adjustment is effected, the carbon
holders in this case simply forming guides which may be either fixed or turn on
their own axis, when they also form part of the train of adjusting mechanism. In
other words, the carbons themselves are kniematic elements gearing directly with
the other parts of the mechanism for transmitting motion and forming an integral
part of such mechanism, the carbon holders forming also parts thereof or not, ac-
cording to circumstances. The motor employed for the adjustment of the carbons
may be of any suitable kind, such as a spring or weight, or an electric motor for
instance.
The accompanying Drawings represent two examples of the carbons of this
Invention. Figure 1 is a longitudinal section showing the carbons formed with a
screw thread a upon them throughout their length; b is one of the holders,
separately represented in Figure 2, formed with a female screw of corresponding
pitch through which the carbon a works. The holder b is fitted to turn in collars c,
and has formed on one end a crown wheel or circle of teeth d with which gears a
pinion e, forming part of the adjusting mechanism actuated by the motor. The
carbon holder 6 is prevented from moving longitudinally and it thus forms a nut
by whose rotation the carbon is caused to traverse longitudinally through the nut,
Prine A1

page_text: the carbon being prevented from partaking in the rotation of the holder b by a
disc ffixed to the butt end of the carbon and sliding in a sheath g attached to the
lower collar c, said disc having a stud h which slides in a longitudinal slot in the
sheath; or the sheath may be replaced by three or more rods.
Both carbons are similarly formed and operated.
The desired approximation of the carbons for establishing the light is effected by
rotating one of the two carbon holders b.
Instead of screw threading the carbons, the nuts or female screws in the holders
may be formed of a screw thread or segment of a screw sufficiently sharp or acute,
or of a disc with cutting edges arranged in a helical position to bite and feed the
carbons forward regularly.
Figure 3 shows another arrangement in which the carbons are provided with
rack teeth along one face. The holder b is in this case a fixture and merely serves
as a guide for the carbon which is made to gear with a toothed wheel j forming
part of the transmitting mechanism operated by the motor.
Figure 4 shows the manner in which the carbon may be attached to a metallic
prolongation, either screw threaded or toothed, to correspond with the carbon itself
so as to enable the whole of the carbon to be utilised and thus avoid waste.