IMPROVEMENTS IN REGULATORS FOR ELECTRIC LAMPS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents on the 20th July 1880.
A com-
munication from abroad by John Henry Guest, of Brooklyn, in the County
of Kings, State of New York, United States of America.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN REGULATORS FOR ELECTRIC
LAMPS." [A communication from abroad by John Henry Guest, of Brooklyn, in
the County of Kings, State of New York, United States of Amorica.]
The object of this Invention is to furnish means for automatically regulating
the length of the arc in electric lamps, and to prevent fluctuations in the light by
changes in intensity of current.
The Invention consists primarily in a thermoscopic rod combined with an
electric lamp for expansion, according to the intensity of the current and resistance
in the circuit. The lineal expansion is multiplied by levers, which act by clamps
to separate the carbons. The Invention also consists in the combination with the
expansion rod of a section of carbon or metal of low conductivity, whereby the
heat due to resistance is rapidly generated and dissipated; also in a shunt for
dividing the current when the carbons are separated to a definite point, and in
certain other details of construction, which render the action more perfect and
adjustable.
The table of the lamp is suitably supported or suspended, and may be of wood,
slate, or other nonconducting material, and to its underside is attached a tubular
guide for the rod of the upper carbon holder, and from it depend rods carrying a
cross rod, to which is fixed the holder of the lower carbon. The rod of the upper
holder passes through an aperture in the table, and on the upper side of the table
the regulating devices next described are placed. Any suitable supporting frame
may be used, whereby the parts are brought into proper relation as described.
On the upper side of the table is a fixed bridge supporting a tubular guide for
the rod of the upper holder, which guide is formed with an external thread to
receive a screw cap, so that the cap is sustained by the bridge, and may be adjusted
vertically. The clamps consist of half tubes attached to the short arms of levers
that are hung from opposite sides of a ring which encircles the clamps, the aperture
of the ring being large enough to allow free movement of the clamps in closing
upon or releasing the rod. The table is furnished with brackets which support
levers, the longer arms of which extend beneath the outer ends of the levers of
TD 971

page_text: the clamps, and carry friction rollers of nonconducting material that are nanged
to prevent the levers turning with the clamps. The shorter arms of the supporting
levers are in contact with the longer arms of levers, which are fitted at their
shorter ends with screws that bear upon the outer ends of the expansion rods,
which consist of tubes perforated at intervals to permit the passage of air, and
secured rigidly by one end to a central support that is attached to the tablo.
The support consists of two brackets, between which is a yoke that is provided
with screw ends and nuts, by which pressure may be given to plates of mica or
other nonconducting and infusible material that are upon the screws. Between
the plates and the brackets are strips of carbon or other suitable resisting medium,
and between the plates and the clamping nuts are springs, so that the carbon will
be pressed upon the brackets by spring pressure. Other devices may be used for
connecting the two tubes by the carbon, and the brackets may be slotted to receive
the ends of carbon rods or strips:
By this construction the expansion of the expansion rods or tubes under heat is
from the fixed central support outward, so that the lovers are simultaneously
moved, and the movement by expansion multiplied by the lovers. The electrical
connections are to one bracket through supporting lever and expansion rod to the
other bracket, and from thence to the other carbon holder. Upon the bracket that
is connected with the entering wire is fixed a spring arm, which is bent over the
lever of the clamp at that side, so that when said lever rises to a certain point it
makes contact with this arm, and shunts the current directly to the carbons by
the rod of the upper carbon holder. The arm is adjustable by bending or otherwise,
so that the current shall be shunted before the expansion tubes become too
intensely heated.
The operation is as follows:-The-parts-should be adjusted by the screws and
screw cap, so that the clamps rest on the cap, and the outer ends of the levers of
the clamps dropped to release the upper carbon holder, the friction rollers being in
contact, or nearly so, with said levers. The circuit being then closed, the resistance
strips or sections connecting the expansion tubes quickly heat, the tubes expand,
the levers are raised, and the clamps binding on the rod of the carbon holder raise
the same and separate the carbons. This movement is instantaneous, and continues
until the resistance in the arc prevents further heating of the tubes. As the arc
increases in length by waste of the carbons the expansion tubes cool and contract,
the levers drop, and the rod of the upper carbon holder is released, so that it may
drop until the tubes again expand and raise it as before.
The effect of the resistance sections of carbon or other material is to ensure a
quick heating and cooling, and to equalise the effect of the heat on the tubes, so
that the levers shall rise and fall alike. A rod of German silver or other metal of
low conductivity may be used without the resistance sections. Two expansion
rods placed parallel may be used. In this case the rods are secured adjustably by
one end to fixed brackets, and their opposite ends are in contact with the shorter
arms of levers. One rod thus noves the lever at one side, and the other the lever
at the other side. The rods are separated at their mid-length, and connected by
an inserted section of carbon. A single lever may be used, and other details of
the construction may be varied without departing from the Invention.