Improvements in Incandescent Electric Lamps.
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements in Incandescent Electric Lamps.
I, HENRY GREEN, of No. 3 Belmont Street, Hartford, Connecticut, United
States of America, Electrician, 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 :-
The object of my invention is to provide in an incandescent electric lamp, a
constantly active mechanical agent adapted and tending to positively force the
stopper of the lamp into the neck of the bulb and prevent the vitiation of the
vacuum in the lamp by leakage around the stopper.
It is well known in the art that the stoppered lamps, while preferable on account
of certain features, are open to the objection that after the creation of the vacuum
within the bulb, the expansion of the parts under heat is liable to cause leakage
between the stopper and the neck of the bulb. By my invention, any leakage
from such cause is prevented by the employment of a constantly active agent, or
stopper-driver, tending constantly to force the stopper into the bulb and thereby
cause the stopper to immediately occupy the least space occasioned, or tending to
be produced, between the stopper and the neck of the bulb by any change by
expansion in either one or both of those elements of the structure.
In the drawing accompanying and forming a part of this Specification,
Fig. 1 is a central vertical section of an incandescent electric lamp, of the
stoppered class, embodying my invention.
Fig. 2 is a similar view of the flanged stopper-retaining cap.
Fig. 3 is a sectional view, similar to a portion of Fig. 1, of the stopper provided
with one form of stopper-driver.
Fig. 4 is a view similar to a portion of Fig. 1, showing another form of stopper-
driver and the mode of applying the same.
Similar characters designate like parts in all the figures.
In the drawing, the usual bulb of the incandescent lamp is designated by a, and
the neck of said bulb by a'. The enlarged end of the bulb is shown provider
with an external thread, t, on which is screwed the retaining-cap d. The inner
side, or bore, of the neck of the bulb is formed tapering at for a part of the
length thereof to form a stopper-bearing or seat, and a stopper, b, is fitted to have
a bearing in said bore upon said stopper-seat. In said stopper are the usual
wires, k and 1, by means of which to make connection with the electric conductors
in the usual socket for receiving the lamp; into which socket the lamp is adapted
to be inserted by means of the external thread of said retaining-cap d. Between
the flange g of the retaining-cap and the outer end of the stopper b, I insert a
constantly active mechanical agent or device, which I designate as a stopper-
driver," and which tends at all times, when the lamp is fully assembled, to urge
the stopper into the tapered neck of the bulb and thereby cause the stopper to
advance on any enlargement taking place, by the heating or otherwise, of the
neck of the bulb.
<
The stopper-driver may consist of a solid piece of elastic or expansive material,
as, for instance, the disk, c, of vulcanized india-rubber shown in place on the
stopper in Fig. 3, and in place between the stopper and an intermediate cap, m, in
Fig. 1. In some cases, the stopper-driver may consist of two disks, e-e, separated
by spiral push-springs, f, as illustrated in Fig. 4. Other modifications of the stopper-
driver will be obvious from and by comparison of the drawing with this descrip-
tion; and I do not limit myself to the particular character of this element of my
improved incandescent lamp.

page_text: In some cases, the flange, g, of the retaining-cap d may bear directly upon the
stopper-driver; but in order to bring the said flange to bear properly on said
driver, and also to provide for making the required electrical contacts for
supplying electrical current to the filament-wires and k, I prefer to employ the
cap m, which may be of the usual composite character, having the central con-
ductor-piece w for contacting with the filament-wire l, and the radially-disposed
conducting-piece for contacting with the flange ; through which flange and
conductor-piece the electrical circuit is usually, in practice, completed.
For operatively supporting the stopper-driver against the end of the stopper, I
prefer to employ the retaining-cap herein described; but any other suitable
means for similarly holding said stopper-driver in working position and under
compression may be substituted for said retaining-cap, without departing from my
present invention.
To assemble the lamp, the stopper having been provided with the conducting
wires and these with the usual filament, i, the stopper is then inserted in place in
the neck of the bulb, the stopper-driver is placed in the upper end of the bulb-
neck, upon the end of the stopper, and the stopper-driver-holding device is then
fixed in place and adjusted to bring the required pressure upon said driver for
positively and constantly forcing the stopper to its seat within the neck of the
bulb. The end of the bulb-neck, in this instance, serves as a retaining-case or
envelope, so that the force of the stopper-driving mechanism described is properly
exerted directly upon the end of the stopper.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what 1
claim is:
1. The herein-described incandescent electric lamp, consisting in the combina-
tion with a bulb having a stopper-bearing within the neck thereof, of a filament-
'carrying stopper fitting said bearing within the neck, a constantly-operative
stopper-driver substantially as described, and means for forcibly holding the
stopper-driver in working position against the stopper, substantially as described
and for the purpose specified.
2. In a stoppered incandescent lamp, the use of a stopper seated upon a tapered
bearing in the neck of the bulb, in combination with a mechanically-active
stopper-driving apparatus held in position to bear with a pressure against the
stopper, substantially as described and for the purpose set forth.
3. In an incandescent lamp of the class specified, the combination with the bulb
having the externally-threaded neck and the internally-tapered bearing for a
stopper, of the filament-carrying stopper seated on said tapered bearing within the
neck of the bulb, a cap engaging said external thread, and a stopper-driver device,
substantially as described, intermediate to said cap and the stopper; substantially
as and for the purpose herein described.
Dated 14th day of November 1893.
Haseltine, Lake & Co.,
HENRY GREEN.
45, Southampton Buildings, London, W.C., Agents for the Applicant.