Improvements in Incandescent Electrical Lamps.
Year: 1895

page_text: Date of Application, 22nd Nov., 1895-Accepted, 28th Dec., 1895
Improvements in Incandescent Electrical Lamps.
We, THE EDISON AND SWAN UNITED ELECTRIC LIGHT COMPANY LIMITED,
and ALFRED WILLIAM HILL, all of Ponders End, in the County of Middlesex,
Electrical Engineers, 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 :-
This invention relates to the construction of the bulb and holder of an
incandescent electrical lamp in such a manner as to shorten the leading in wires
and lessen the risk of their short circuiting, and to afford ready means of putting
the filament or one of two filaments in or out of circuit.
Fig. 1 of the accompanying drawings is an elevation of a bulb and holder
according to this invention, the casing of the holder being shewn in section.
Fig. 2 is a sectional plan on the line X X of Fig. 1.
Fig. 3 is a plan of the holder looking from below.
Fig. 4 is a plau and section of the disc and contact plates for a lamp having a
single filament, and Fig. 5 is a similar plan and section for lamp having two
filaments.
The bulb B terminates above with a hollow fitted to receive a disc D of ceramic
or other non-conducting material cemented in the hollow, and having fixed on its
upper face a pair of contact_plates C as shewn in Fig. 4, or three such
plates C C C³ as in Fig. 5. The two leading in wires for a single filament are
passed through holes in the disc into holes of the contact plates C in which they
are soldered.
When there are two filaments in the bulb, each has one of its ends secured
to a separate leading in wire, and the other ends of both are secured together to
another leading in wire, the three wires being connected to the three contact plates
shewn in Fig. 5.
The spring plungers P are mounted as usual in a base M of nou-conducting
material and are connected to the leading conductors W, the base M being secured
to the cone N by screwing on to N a socket S, which terminates in a number of
circularly arranged spring blades E. The bulb B has a projecting lip L forming
a bead all round its head, this lip lodging in hollows of the spring blades E when
it is pushed in with sufficient force to push the blades outwards so as to let it pass
to the position where it is held by their elastic pressure. In thus pushing in the
head of the bulb the contact plates C are pressed on the plungers P. By turning
the bulb partly round to one position the two plates C of Fig. 4 may be brought to
face the plungers P thus putting the filament in circuit; by turning the bulb about
one quarter round, the filament is put out of circuit." In like manner when
there are three contact plates C' C C as shewn in Fig. 4, the plate C' may face
one plunger while either of the plates C2 C3 or the near edges of both face the
other, and thus either or both filaments may be put in circnit. By turning the
bulb to such a position that C' does not face either plunger P, both filaments are
put out of circuit.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
An incandescent electric lamp having the head of its bulb formed with a hollow

page_text: filled with a disc carrying contact plates connected to the leading in wires, and
having a projecting lip or bead, in combination with a holder provided with spring
contact plungers, and having circularly arranged spring blades hollowed to receive
the lip of the bulb, substantially as described.
Dated this 22nd day of November 1895.
ABEL & IMRAY,
Agents for the Applicants.