Year: 1886

page_text: Date of Application, 26th Jan., 1886.
Complete Left, 26th Oct., 1886.
Complete Accepted, 5th Jan., 1887.
We, OTWAY EDWARD WOODHOUSE, and FREDERICK LAWRENCE RAWSON, of
No. 11 Queen Victoria Street, in the City of London, Electrical Engineers, do
hereby declare the nature of this invention to be as follows:-
Our invention relates to incandescent electric lamps, and consists in constructing
them with two or more separate filaments of different candle power, placed in one
globe, or combined in action, but in separate globes, so that a filament of smaller
candle power is available for use at such times as the larger filament is destroyed, or
when only a little light is required, and by the introduction of a resistance, various
modifications of circuit in parallel or series through the two or more filaments enable
various modifications of lighting effect to be obtained by the use of suitable switches.
The filaments may be arranged in any convenient way to one another within the
lamp, and their leads or terminals are so connected to suitable contacts either in the
base of the lamp or at some little distance from it, that by the combination therewith
of an ordinary switch, the current may be diverted from à larger to a smaller filament
at pleasure, or vice versa.
A suitable resistance may be introduced either in the circuit of the smaller filament,
or in the switch, so that any danger to the said smaller filament by excess of current
may be avoided when the current is switched from the larger to the smaller filament.
A suitable resistance may also be introduced (in series when the lamps are burnt in
multiple arc, and in parallel to the filament when the lamps are burnt in series) with
either of the filaments either inside or outside of the bulb, so as to avoid the difficulty
of manufacture, it being difficult to construct lamps with two filaments in one globe.
The resistance is such that both of the filaments burn equally brilliantly with the same
electro-motive force, when in multiple arc, or with the same current when in series.
When a filament has a resistance arranged with it, so as to render it equally brilliant
with the other filament, the lamp should be arranged so that the working filament or
filament usually or most often used, should be the one without the resistance. We
can also, instead of having two filaments of different size and candle power but of the
same brilliancy, as mentioned previously, for use as a night light, have two filaments
of the same size, but different brilliancy, thus making use of the lamps in which the
Price Sd.1

page_text: two filaments are not of equal brilliancy, which otherwise would be wasted. We may
also combine with this lamp an automatic switch of any known description, arranged
so that on the rupture of the larger filament the smaller filament may be automatically
lit
up, and thus call attention to the rupture of the first filament. The ringing of an
electric bell may be also used for this purpose. To obtain a bright or subdued light at
will, we may have the two or three filaments in the lamp arranged in multiple are for
the bright light, with an arrangement to switch the two filaments in series whenever
a subdued light is required. We may also arrange the two filaments of different
candle power so that on putting the two lamps in series, the filament of smaller candle
power lights up brilliantly, whilst the filament of larger candle power is quite dull or
even black, on account of its requiring more current than the smaller one to raise it
to the same brilliancy.
FELL & WILDING,
Agents for the Applicants.

page_text: We, OTWAY EDWARD WOODHOUSE and FREDERICK LAWRENCE RAWSON, of
No. 11 Queen Victoria Street, in the City of London, 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 :-
Our invention relates to incandescent electric lamps, and consists in constructing
them with two or more separate filaments of different candle power placed in one
globe, or combined in action, but in separate globes, so that a filament of smaller candle
power is available for use at such times as the larger filament is destroyed, or when
only a little light is required, and by the introduction of a resistance various modifica-
tions of circuit in parallel or series through the two or more filaments enable various
modifications of lighting effect to be obtained by the use of suitable switches.
The filaments may be arranged in any convenient way to one another within the
lamp, and their leading terminals are so connected to suitable contacts either in the
base of the lamp or at some little distance from it that, by the combination therewith
of any ordinary switch, the current may be diverted from a larger to a smaller filament
at pleasure or vice versa.
This is shown in figure 1 where A is the larger filament, B is the smaller one, and
C the switch by which the current may be diverted from the larger to the smaller
filament or vice versa at pleasure.
A suitable resistance may be introduced either in the circuit of the smaller filament
or in the switch, so that any danger to the said smaller filament by excess of current
may be avoided when the current is switched from the larger to the smaller filament.
A suitable resistance may also be introduced (in series when the lamps are in
multiple are, and in parallel to the filament when the lamps are in series) with either
of the filaments either inside or outside of the bulb, so as to avoid the difficulty of
manufacture, it being difficult to construct lamps with two filaments in one globe the
resistance of which is such that both of the filaments burn equally brilliantly with the
same electro motive force when in multiple arc, or with the same current when
in series.
This is shown in figures 2 and 3, in which the filaments are in multiple arc and series
respectively, A A being the lamps in multiple arc, D D the resistances combined either
with or without the switches CC, by which the filaments may be either cut out entirely
or the resistances inserted at pleasure. In figure 3, the filaments A A are in series,
the centre filament being provided with an ordinary cut out switch Cone filament
being provided with a resistance D constantly in circuit at the cut out switch C the
other filaments A" having the resistance D brought into parallel circuit at pleasure by
the switch C¹
When a filament in a two filament lamp has a resistance arranged with it, so as to
render it equally brilliant with the other filament, the lamp should be arranged so that
the working filament or filament usually or most often used, should be the one without
the resistance. We can also, instead of having two filaments of different size and
candle power but of the same brilliancy, as mentioned previously for use as a night
light, have two filaments of the same size but different brilliancy, thus making use of
the lamps in which the two filaments are not of equal brilliancy, which otherwise would
be wasted.
We may also combine with this lamp an automatic switch of any known description,
arranged so that on the rupture of the larger filament the small filament may be auto-
matically lit up, and thus call attention to the rupture of the first filament. The
ringing of an electric bell may also be used for this purpose.

page_text: A known arrangement of automatic switch, is shown at figure 4, where A and B
are the two filaments, C the switch operated automatically by an electro magnet or
solenoid E, by any change in the current consequent upon the rupture of one of the
filaments.
To obtain a bright or subdued light at will, we may have the two or more filaments
in the lamp arranged in multiple are for the bright light, with an arrangement to
switch the filaments in series, whenever a subdued light is required.
This is shown in figure 5, where the two filaments A and B are in multiple arc for a
bright light, the switch C enabling the user to switch the lamps into series to subdue
the light when required.
We may also arrange the two filaments of different candle power so that on putting
the two lamps in series, the filament of smaller candle power if normally taking the
same electro-motive force as the larger candle power filament, lights up with fair
brilliancy whilst the filament of larger candle power is quite dull or even black on
account of its requiring more current than the smaller one to raise it to the same
brilliancy. Or the two filaments of different candle power may be permanently
arranged in series, so that when the same current passes through both, the smaller
filament only is rendered sufficiently incandescent; but when a greater light is required
the smaller filament is short circuited by a switch, and thus sufficient current is allowed
to pass through the larger filament to render it highly incandescent.
This is shown in figure 6, where the two filaments A and B of different candle power-
are in series. The switch Cenables the operator to short circuit the smaller filament B
and thus to allow a sufficient current to pass through the larger filament to render it
highly incandescent.
Figure 7 shows a method of switching the current by a thermostatic land G, which
breaks contact at H when heated by excess current.
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 :—
1st. In an incandescent electric lamp the combination of two or more filaments
therein of widely different candle power with any known electrical switch controlled
automatically by the current or by hand by which the current may be diverted from
the larger to the smaller filament or filaments or vice versa, at pleasure, substantially
as described.
2nd. In an incandescent electric lamp the combination of two filaments therein of
widely different candle power with any known automatic or hand switch and a suitable
resistance in circuit with the smaller filament to prevent rupture of the latter, substan-
tially as described.
3rd. The combination of two or more filaments of widely different candle power in
separate globes with any known antomatic or hand switch and a resistance in the
circuit of the smaller filament or filaments in series when the larger and smaller
filaments are in multiple are, and in parallel when the larger and smaller filaments are
in series, substantially as described.
4th. The combination of two or more incandescent electric light filaments in one or
more globes, the filaments being arranged in multiple are for a bright light with any
known switch, by which the filaments may be placed in series for a sulxlued light,
substantially as described.
5th. The combination of two or more incandescent electric light filaments of widely
different candle power in one or more globes, the filaments being in series when small
light is required, with any known switch by which the smaller filament or filaments
may be short circuited, to allow the larger filaments to become incandescent, substan-
tially as described.
FELL & WILDING,
1, Queen Victoria Street, London, E.C.,
Agents for the Applicants.