Improvements in Incandescent Electric Lamps.
Year: 1896

page_text: Date of Application, 22nd Sept., 1896-Accepted, 13th Mar., 1897
Improvements in Incandescent Electric Lamps.
We, JOHN THOMAS LISTER Electrician, and WILLIAM SELAH CHAMBERLAIN
Gentleman, both of 235 Harkness Avenue, Cleveland, Ohio, in the United States
of America, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
Our invention relates to improvements in incandescent lamps, and the objects of
the invention are to provide means for increasing the durability and power of the
lamp, and in addition thereto to provide a form of lamp which will afford a free
passage to the light in all directions and will present no interfering parts to cast
shadows.
Our invention consists in the shell of symmetrical form, and in the adoption of a
pair of filaments and circuit terminals therefor, the circuit terminals for one pair
of filaments being at one end of the shell and the circuit terminals for the other
filament being at the other end of the shell.
These circuit terminals are so placed in the shell as to readily make exterior
connections with the circuit wires, and the filaments are so mounted as to pass one
another in the shell without touching at their free extremities.
Our invention further consists in the construction and arrangement of the various
details, as hereinafter described, shown in the accompanying drawings, and more
specifically pointed out in the claims.
In the accompanying drawings
Fig. 1 is a side elevation of the shell and enclosed filaments;
Fig. 2 is a plan view of the lamp ;
Fig. 3 is a detail of the construction of the neck of shell and disc in which the
circuit terminals are inserted.
In these figures 1 is the shell, 2 are the filaments inserted in the closed
extremities, at 3 and 4.
The cap 5 is designed to spring over the shell extremities which are beaded at 6
to secure slight projections 7 upon the sides of the cap. Notches 8 permit the
projections to pass under the beads.
The contact points for the terminals of the lamp circuits are shown at 9 and 10
in the cap 5; one extremity being insulated from the cap.
In constructing the shell the circuit terminals for the filaments are inserted in
glass discs 11 as seen in Fig. 3, which are afterwards secured by fusion upon the
shell openings, thus making the parts easy of construction.
We do not claim the exact shape of the shell although the shape of the
extremities should be preferably uniform, nor do we claim the exact method of
hanging the lamp, whether horizontally or vertically. In neither position could
shadows interfere with the light from the lamp.
It will be seen that by means of suitable connections with the circuit wires one
or both filaments can be utilized, or one filament can be used continuously until
worn out, when the other can be lighted, thus doubling the life or power of the
lamp at pleasure.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. In an incandescent lamp the combination, with a shell, of a pair of filaments

page_text: and circuit terminals therefor, the circuit terminals for one filament being at one
end of the shell and the circuit terminals for the other filament being at the
other end of the shell, substantially as described.
2. In an incandescent lamp the combination, with a shell, provided with uniformly
shaped and open extremities, of a pair of filaments and circuit terminals therefor,
and transparent discs in which said circuit terminals are inserted, the circuit
terminals for one filament and disc in which the said terminals are inserted being
at one end of the shell and the circuit terminals for the other filament and disc in
which the said terminals are inserted being at the other end of the shell, substantially
as described.
Dated this 22nd Santambor 1906
CHARLES JUNGE,
Agent for the Applicants.