IMPROVEMENTS IN ARC ELECTRIC LAMPS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Frederick Leopold Willard at the
Office of the Commissioners of Patents on the 31st October 1882.
FREDERICK LEOPOLD WILLARD [85] Hoxton Street London IMPROVEMENTS IN
ARC ELECTRIC LAMPS
Attached to an
My invention relates to improvements in Arc Electric Lamps
iron core sliding within a solenoid, or solenoids, one of which may be wound to a
bigher resistance than the other, and placed in a shunt circuit, so as to act differentially,
or to an armature of the type common to Electric Lamps in which the feed is
controlled by an Electro-magnet, are two cams connected by a slot link, which is
secured by a pin, to the can on one side, but assists in raising and controlling the
action of the cam, opposite to it, by means of a pin fastened to such can, which
travels in the grove or slot provided for it in the link. The action of the cam is
to grip the rod carrying the upper carbon, and to prevent its too rapid
descent. In order that the feed may be properly regulated a small lever is affixed
to one of the cams, and is so placed, as to touch a striking pin or adjustment screw,
when the core of the solenoid, or the armature of the electro-magnet falls below a
fixed point, owing to decrease in the magnetization of such solenoid or electro-
magnets, from the lengening of the arc, or when the current passing through the
shunt or differential coil, above referred to, which receives the lower end of the
iron core is sufficient to overcome the magnetic influence exerted upon such core,
by the solenoid opposed to it in the main circuit. The effect of the lever touching
the striking pin or adjustment screw is to raise both cams from off the rod
carrying the upper carbon, which then slips downwards, by gravity, so shortening
the arc, restablishing the current, and increasing the magnetization in the main
solenoid, or electro-magnet, so that the core or armature is drawn up and the lever
lifted from the striking pin or adjustment screw, the rod being firmly held by the
two cams. Another part of my invention consists in the method of connecting the
carbons with the main circuit, and the solenoid or electro-magnet. Usually the
solenoid or electromagnet is included in a coil forming part of the main circuit, I
prefer however to connect my carbons directly with the main circuit, and to include
the upper or controlling solenoid or electro magnet in a derived circuit, on one side
of the arc, so that the current splits as between carbon electrode, and the coil of

page_text: the solenoid or electromagnet, while if a shunt or differential coil be used, in
addition to the controlling solenoid or electro-magnet, this coil forms a bridge
between the terminals of the lamp. By suitably winding the solenoid or electro-
magnet, the exact amount of current required to give the solenoid or electro
magnet the requisite lifting power, can be supplied to the derived circuit in which t
it is placed, permitting the greater part of the current to pass direct to the carbon
electrodes, to produce the light
I also plate the iron core, which actuates the lamp with some non oxidizable
metal, such as nickel Gold, tin, Zinc, & platinum, and I so construct the lower
solenoid, as to form what is known as a "dash-pot" filled with glycerine or oil, 1
which checks the too sudden descent of the iron core, and gives a steady action to
the lamp.