Improvements in Electric Incandescent Lamps.
Year: 1892

page_text: Date of Application, 21st Dec., 1892
Complete Specification Left. 28th July, 1893-Accepted, 2nd Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Electric Incandescent Lamps.
We, ALBERT ZOBEL and FRITZ BUCHMÜLLER, both of Pilotzstrasse 7,
Munich in the Empire of Germany, Merchants, do hereby declare the nature of
this invention to be as follows:-
This invention relates to electric incandescent lamps and the improvements
consist in supplying each lamp with two filaments with connections thereto so
arranged that both these filaments may be inserted simultaneously in the circuit if
so desired thus giving a lamp of double power, or else the one filament may only
be brought into the circuit at some future time after the other filament has been in
action, for instance after the latter filament has been broken or destroyed in use,
thus providing a lamp having a double length of life.
For these purposes two filaments are fastened in each lamp to three connecting
wires; one of these wires is connected to one end of both filaments and other two
ends of the two filaments are connected respectively to the other two wires.
The first wire which forms a lead common to both filaments is connected to one
pole of the lamp for instance the usual surrounding screw threaded metal sleeve,
while one of the other wires is connected to the other pole usually the cap inserted
at the end of the plug of the lamp, the third wire is carried out through the
gypsum or other insulating material and is left with a free disconnected end. In
this state, when the lamp is fixed in its socket the current will be led through one
filament only. If both filaments are to be used simultaneously the free wire is also
connected to the cap and the current will be divided and pass through both
filaments. If the connection of the free wire to the cap is deferred until the first
filament fails, the lamp may be used with the first filament until that breaks where-
upon the lamp is removed, the free wire joined to the cap and the lamp again
screwed into its socket when the second filament will enter into action.
In place of making the third wire as a free projecting wire, this wire may be
imbedded only in the glass of the lamp so that it projects on the inside and not
on the outside of the lamp; in this case there is provided within the lamp a
movable ring, plate, hook, fork or wire so arranged that by a movement given to
the lamp this device will bring the second wire into electrical connection with the
third wire. Until this movement is made the current will only pass through one of the
filaments namely that whose ends are connected to the first and to the second wires
respectively, but when this connecting device is brought into action, the third wire
which had formerly stood as an insulated wire is brought into electric conuection
with the second wire and the current will pass through both filaments, unless the
first is broken in which case it will pass through the second filament.
Dated this 21st day of December 1899
R. HADDAN,
Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in Electric Incandescent Lamps.
We ALBERT ZOBEL and FRITZ BUCHMÜLLER both of Pilotzstrasse 7,
Munich in the Empire of Germany, Merchants 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 electric incandescent lamps and the improvements

page_text: consist in supplying each lamp with two filaments with connections thereto so
arranged that both these filaments may be inserted simultaneously in the circuit if
so desired, thus giving a lamp of double power, or else the one filament may only
be brought into the circuit at some future time after the other filament has been in
action, for instance after the latter filament has been broken or destroyed in use,
thus providing a lamp having a double length of life.
For these purposes two filaments are fastened in each lamp to three connecting
wires; one of these wires is connected to one end of both filaments and the other.
two ends of the two filaments are connected respectively to the other two wires.
The first wire which forms a lead common to both filaments is connected to one
pole of the lamp for instance the usual surrounding screw threaded metal sleeve
while one of the other wires is connected to the other pole usually the cap inserted
at the end of the plug of the lamp, the third wire is carried out through the gypsum
or other insulating material and is left with a free disconnected end. In this state
when the lamp is fixed in its socket, the current will be led through one filament
only. If both filaments are to be used simultaneously the free wire is also
connected to the cap and the current will be divided and pass through both
filaments. If the connection of the free wire to the cap is deferred until the first
filament fails, the lamp may be used with the first filament until that breaks, where-
upon the lamp is removed, the free wire joined to the cap and the lamp again
screwed into its socket when the second filament will enter into action.
In place of making the third wire as a free projecting wire, this wire may be
embedded only in the glass of the lamp, so that it projects on the inside and not on
the outside of the lamp, in this case there is provided within the lamp a movable
ring, plate hook, fork or wire so arranged that by a movement given to the lamp
this device will bring the second wire into electrical connection with the third wire.
Until this movement is made, the current will only pass through one of the
filaments namely that whose ends are connected to the first and to the second wires
respectively, but when this connecting device is brought into action, the third wire
which had formerly stood as an insulated wire is brought into electric connection
with the second wire and the current will pass through both filaments, unless the
first is broken, in which case it will pass through the second filament.
These improvements can be employed on any kind of known construction of
incandescent lamps.
In the annexed drawing
Fig. 1 is an elevation of an incandescent lamp with two filaments.
Fig. 2 shows a section through the neck of the lamp.
Fig. 3 shows the lamp connected in parallel.
Figs. 4, 5 and 6 are alternative constructions.
Three conducting wires 1. 23 are melted into the lamp. Two of these 1 and 2,
are connected as usual with the filament u, one of thein namely 2 being also in
connection with one end of the second filament b, the other end being connected to
the third wire 3.
The third wire 3 projects from the lamp, being insulated by the gypsum as shown
at 4, Fig. 1.
The filament a in Fig. 3 being for instance interpolated, the current runs from
the main conductor I through branch III, the screw frame piece of the lamp, the
wire 2, filament a, wire 1 to the cap IV and back to the second main conductor II.
When the filament a is burned out the end 4 of the third conducting wire 3 is
soldered on the contact plate IV as shown by dotted lines in Fig. 3.
The current now runs from I through III to the wire 2 through the filament b,
wire 3, back to the main conductor II.
If the lamp is required to give double light, the third wire is placed on the
contact plate of the frame so that both filaments enter the circuit.
In the construction shown in Figs. 4, 5 and 6 only the two conducting wires 2
and 3 pass through the bottom of the glass. The wires 2 and 3 are connected as
usual by the filament . At some distance from these two conducting wires 2 and 3

page_text: a third wire 1 is melted into the glass so that it projects only on the inside of the
lamp. It only passes half through the glass in order not to detract from the air-
tight construction of the lamp.
The wires 1 and 2 are connected by the filament a.
The arrangement of an outwardly projected third wire as shown at 4 in Fig. 1 is
here completely avoided.
The interpolation of the second incandescent filament is attained as follows:-
On the wire 3 provided with a double bend as in Fig 4 or with a ring as in Fig. 5,
a movable contact is arranged consisting either of a plate d (Fig. 4) or of a hook.d¹
(Fig. 5) or a fork e (Fig. 6). In case of using a contact plate d the wire 1 is
preferably furnished with a piece of springing wire c (Fig. 4).
The contact plate, made of metal is movably appended to the wire 3, the edge of
the plate being notched. Usually the filament b is alone employed, the current
running through wire 2 filament band wire 3. When the second filament a is to be
brought into action, the lamp is to be turned over and the contact plate d suffered
to fall between the wires 3 and c. By these means an electric contact is attained
between the wires and c and thereby between the two conduction wires 2 and 3
through the filament a. The notches in the edge of the metal plate d serve to
secure this position of the wires.
The current now circulating in the lamp being divided as above described, both
filaments are brought into action. If either filament is burnt out, the current
passes wholly through the remaining filament.
In the variation illustrated in Fig. 5 the contact plate d is replaced by a
conducting hook d; this hook being likewise easily movable on the wire 3 so as to
engage with the wire 1 when the incandescent lamp is suitably turned.
In Fig. 6 a wire e is shown split at its end and fixed to the conducting wire 3.
This wire e is curved in such a manner that the forked end of same is caused to
firmly embrace the wire 1 when a sharp push or jerk is given the lamp so that by
this means contact between the wires 1 and 3 is effected.
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 lamp with two or more incandescent filaments, the latter
capable of being made incandescent singly or together, the interpolation of the
supplementary filament or filaments being effected by addition of a third wire 1
standing out of the lamp or by providing on the conduction wire 3 a movable plate
or wire of hook, fork or any other suitable form so arranged as to leave its insulated
position and effect the contact when an appropriate movement is given to the lamp
substantially as hereindescribed.
R. HADDAN,
Herbert Haddan & Co.,
18, Buckingham Street, Strand, London, Agent for Applicants.