Improvements in Incandescent Lamps.
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements in Incandescent Lamps.
We, ARTHUR STEPHEN FORD, of 153 Fenchurch Street, London, Electrical
Engineer, and WILLIAM BARNES, of 31 Witt Road, Widnes, near Warrington, in
the County of Lancashire, Manufacturer 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 electric lamps and consists of an improved incandescent
lamp also in modifications of construction and the arrangement of parts, more
particularly designed as applicable to incandescent lamps.
One of the great objections to the usual form of incandescent lamps is that the
glowing filament as ordinarily arranged, leaves an unpleasant impression on the
retina of the eye after the gaze has been removed from the lamp.
To overcome this defect manufacturers have had recourse to various methods
such as dulling, frosting, or engraving the glass bulbs or applying shades etc.
These means whilst only partially effective have the great economic drawback of
involving a serious loss of light, nearly 40% of light being lost with the use of
frosted globes.
Our invention provides a means whereby this objectional "glare" is removed
without involving any appreciable loss of light.
Another objection in the ordinary lamp is that its lighting value is fixed or
constant and that whatever the lighting facility required this can only be obtained
by increasing or decreasing the number of lamps in circuit.
By our invention we provide a multi-power lamp so constructed that any lamp
may be used with alternative or more values as, for example our improved lamp
can be arranged to limit a 15, 30, 45, or other candle power as desired.
This is effected
Another valuable feature in our lamp is the saving of current.
by an arrangement of the filament in such a manner, that an equal lighting
efficiency to that obtained in the ordinary lamp is obtained in our lamp after the
power of the current has been materially reduced. Another feature of our
improved lamp is that no shades or outer globes are necessary as the light can be
transmitted in any desired direction by arrangement of the lamp itself.
For specific purposes such as photographic, advertising or other uses we provide
means whereby the light may be focalized as required.
The accompanying sheets of drawings serve to fully illustrate our invention.
Fig. 1, Sheet 1, shows an elevation of one modification of our improved lamp,
Fig. 2 being a plan of same, Fig. 3 a section, and Fig. 4 a sectional plan.
Sheet 2 Fig. 5 shows an elevation of our lamp clamped in a holder, Fig. 6 a
section where a double filament is employed, and Fig. 7 a further modification.
Sheet 3, Fig. 8, shows modification in the constructional form of receiver
Fig. 9, being a sectional plan thereof and Fig. 10 a further modification.
In Fig. 1, it will be seen that the glass receiver is constructed in a form roughly
resembling a thistle with a lower swelling base A. A, designed to receive the
filament within it. The arrangement of the filament will be the better understood
from the inspection of Figs. 3 and 4, in which the filament C C is disposed in a
shape somewhat resembling the letter S and attached to the leading in wires B B..
The swelling base A A of the receiver is silvered next to the glass and is then
protected by a coat of opaque paint composition or in other suitable manner.
will then be obvious that the filament is arranged practically within a silvered.
saucer and its emitted light being reflected forward by the reflecting surface of the
It

page_text: said saucer will be thrown out into the upper part of the receiver in such manner
that (there being no visible source of light) the transparent part of the receiver
will appear to the eye as a glowing bulb of light. The curves of the receiver are
so arranged as to prevent any direct view of the filament being obtained as the con-
stricted formation of the lamp where the base and upper parts join serves to distort
the shape of the filament in the eye of the observer similarly the projecting point at
the crown of the receiver creates an area of disturbance which produces a like effect.
Fig. 5 shows our lamp in conjunction with a holder in which the swelling base is
held within clamps integral with the holder D. Fig. 6 shows the arrangement of
the filament when more than one are used. In the figure two filaments C C
and EE are shown one being superposed on the other. These filaments may be of
the same or different candle power, resistance etc., or relatively different in any
desired particular. In Fig. 7 the base of the glass receiver itself is left in its
natural condition and the reflecting surface is obtained by an outer sheath or
cover Feither integral with or attached to the holder D, this sheath is constructed
of metal or other suitable material and bears a polished reflecting surface upon its
interior which same serves to reflect the light from the filament as before described.
In the same figure portions of the glass receiver G and H are shown frosted etched
or otherwise treated with a view to shield the filament from sight as before:
described.
In Fig. 8 the glass receiver is shown fluted vertically its plan (as shown in
Fig. 9) being of a trefoil shape the filament also in the latter figure is modified as
to its curvature to suit the altered nature of the receiver. This modification has
been designed with a view to creating vertical disturbing influences it being of
course understood that the number of the said vertical divisions are immaterial so
long as the effect desired is obtained:
In practice we have found three sufficient as with this number a vertical filament
of usual type (as shown in Fig. 10) may be utilised with or without a circum-
ferentially disposed filament or filaments without the obnoxious glare already
mentioned. In construction the receivers may be blown in a mould or otherwise as
preferred, but we have found that they can be blown by mouth in a sufficiently
accurate manner as to substantially fulfil the requirements as set forth.
Although in the drawings the reflecting lower portions are shown of a more or
less saucer shape we prefer to form these of a parabolic shape as by this formation
alone are the rays of light from the filament thrown forward, without ultimate
focalization. From experiment and in practice we find that of two filaments
identical in length, resistance and other respects, an increased lighting efficiency is
obtained from the one which presents, the most curves or angles or, in other words
that curves and angles in the filament give greater light than straight lines. We
take advantage of this fact in the arrangement of the filament and dispose the same
in a continuous curve and although we do not confine ourselves to the trefoil shape
or the S shape before described we do claim the use of the filament arranged with
a continuous curve or of a continuous sinuous or angular disposition to secure the
before mentioned advantages.
In constructing our improved lamp for photographing advertising or other
purposes we provide the glass receiver with lenses integral with the receiver to
focalize light and throw it into any desired direction. It is of course obvious that
the construction of the receiver, the reflecting base, the form of holder and the
sheath also the arrangement of the filament or filaments may be jointly or severally
modified without departing from the essence and scope of our invention.
Having now particularly described 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 electrical lamp the circumferential or lateral disposition of the filament
or carbons within a reflecting portion as set forth and shewn in Figs. 1, 3, 4, 5, 6,
7, 8, 9, 10, all substantially and for the purpose as herein before described...
2. In an electric incandescent lamp with an hermetically sealed and exhausted

page_text: glass receiver the use of a circumferential filament arranged in a continuous curve
a continuous sinuous or a continuous angular shape all substantially and for the
purpose as herein before described.
3. In an electric incandescent lamp with an hermetically sealed and exhausted
glass receiver the use of a circumferential filament arranged in a continuous curve
or arranged in a continuous sinuous or a continuous angular shape in combination
with a reflecting portion of the said receiver all substantially and for the purpose
herein before described. .
4. In an electric incandescent lamp with an hermetically sealed and exhausted
glass receiver folds or flutes as shewn in Figs. 8, 9, and 10 all substantially and for
the purpose herein before described.
5. In an electric incandescent lamp an hermetically sealed receiver provided with
a reflecting portion as shewn in Figs. 1 to 10 inclusive all substantially and for the
purpose herein before described.
6. In an electric incandescent lamp a filament arranged circumferentially within
a portion of the receiver all substantially and for the purpose as herein before
described.
7. In an electric incandescent lamp the combination of a vertical disposed
filament with a circumferentially disposed filament all substantially and for the
purpose herein before described.
Dated this 3rd day of November 1893.
HUGHES & YOUNG,
12, Basinghall Street, London, E.C., Agents.