Improvements in the Method of Fixing Caps to Incandescent Electric Lamps, and in Joining the Leading-in Wires of such Lamps to Contact-plates.
Year: 1896

page_text: Date of Application, 25th Feb., 1896
Complete Specification Left, 25th Nov., 1996-Accepted, 25th Feb., 1897
Improvements in the Method of Fixing Caps to Incandescent
Electric Lamps, and in Joining the Leading-in Wires of such
Lamps to Contact-plates.
I, JOHN ARCHIBALD SINCLAIR, of 55, Rowan Road, Hammersmith, London, W.,
Electrical Engineer do hereby declare the nature of this invention to be as
follows:-
The invention consists in fixing the lamp-cap to incandescent electric lamps by
the use of solder or other melted alloy or metal, and in soldering the leading-in wires
directly to the contact-plates of the lamp-cap, without the use of wires joining the
leading-in wires to the contact-plates, as has hitherto been customary.
The method by which I carry out my invention is as follows:-
Dents, A, Figures 1, 2, and 4, which may be about one-sixteenth of an inch in
diameter, and of about the same depth, are formed in the necks of the bulbs. These
dents are preferably formed in the process of blowing the bulbs in a mould, so as to
be all nearly in the same position with regard to each other, and at the same
distance from the shoulder B, Figs. 1, 2, and 4, of the bulb; and at the same
time the necks of the bulbs are made nearly of one diameter, equal to or slightly
less than the inside diameter of the lamp-caps. The bulb thus made is shown in
elevation in Fig. 1.
When the filaments are sealed in, the necks of the bulbs should be as shown in
Fig. 2, which shows a section of the lamp after sealing-in, at right-angles to the plane
of Fig. 1. The necessary length of the leading-in wires outside the glass for joining
to the contact-plates should be as small as possible. In sealing-in the diameter of
the neck must not he sensibly increased.
In Fig. 3 are shewn plans of the top and bottom of the cap, and also a sectional
elevation. The contact-plates have suitable holes pierced through them at D D.
The lamp-caps are pierced with holes, C, Figs. 3 and 4, of about one-sixteenth of an
inch in diameter, in such a position that when the cap is fitted upon the sealed end
of the lamp, with its edge abutting against the shoulder B of the bulb, and the
leading-in wires projecting through the openings D in the contact-plates, the holes C
in the lamp-cap may be brought directly over the dents A in the bulb.
The bulb being suitably sealed-in, as above shown, the cap is fitted on, as shown
in Fig. 4, so that the leading-in wires project through the openings in the contact-
plates, and so that the holes in the cap correspond with the dents in the bulb. A drop
of solder or other fusible alloy or metal is then applied to each of the holes in the
cap, so that it fills up the dent in the glass just below it. A suitable flux may be
used, so that the solder sticks to the lamp-cap, and the sealed end of the lamp may
have been previously heated so as to prevent any cracking due to the hot solder falling
on to cold glass. Superfluous solder may be wiped away. The leading-in wires are
then soldered directly to the contact-plates.
Dated this 23rd day of February 1806

page_text: Improvements in the Method of Fixing Caps to Incandescent
Electric Lamps, and in Joining the Leading-in Wires of such
Lamps to Contact-plates.
I, JOHN ARCHIBALD SINCLAIR, of 17, Elm Gardens, late of 55, Rowan Road,
Hammersmith, in the County of Middlesex, Electrical Engineer, 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 improved means for securing the caps of incandescent
electric lamp bulbs, and the leading-in wires of such lamps, and consists in fixing the
lamp-cap by means of solder or other suitable alloy or metal capable of being applied
in a liquid state, and in soldering the leading-in wires directly to the contact-plates of
the lamp-cap; the use of separate wires joining the leading-in wires to the contact-
plates being dispensed with.
Referring to the drawings which accompanied my Provisional Specification,
Fig. 1 is an elevation of an incandescent electric lamp bulb constructed according
to my invention.
Fig. 2 is a vertical section taken on the centre-line of Fig. 1 showing a filament
sealed in the bulb and the leading-wires protruding therefrom.
Fig. 3 represents a view of the upper side, a vertical section, and a view of the
under side of the improved cap.
Fig. 4 is a vertical section showing the bulb and cap secured together ready
for use.
In carrying out my invention, I form the neck of the bulb with cavities or dents A,
which may be about one-eighth of an inch in diameter, and of about half that depth.
These cavities or dents are preferably formed by moulding, whereby uniformity is
secured both as regards their position in relation to each other, and to the shoulder B
of the bulb. The neck of the bulb is made of a diameter slightly less than the
inner diameter of the lamp-cap in order to facilitate the operation of "capping." In
Fig. 2, I have shown a bulb, such as described, with the filament sealed in; the
view being taken at right angles to the plane of Fig. 1. In sealing-in, care should
be taken not to appreciably increase the diameter of the neck. Referring to Fig. 3,
the contact-plates and the insulation have suitable holes D D formed in them for the
passage of the leading-in wires. The cap is made with holes C placed at intervals in
its circumference coincident with the cavities or dents A in the neck of the bulb.
These holes may be about one-sixteenth of an inch in diameter.
The sealing-in having been accomplished in any suitable manner, the cap (Fig. 3)
is placed over the neck or sealed end of the bulb until its edge abuts against the
shoulder B; the leading-in wires projecting through the orifices D. The holes C in
the lamp-cap are then brought directly over the cavities or dents A in the bulb, when
a drop of solder, or other fusible alloy or metal, is run into each of them, the solder
filling both the cavity in the bulb-neck and the hole in the cap. The cavity is
usually larger in diameter than the hole in the cap, in order that the solder may
spread slightly within the cap; displacement of the latter being thereby more
effectually prevented. The sealed end of the bulb may be heated previously to
applying the solder in order to prevent cracking, which might otherwise occur upon
the hot solder coming into contact with the cold glass. The leading-in wires are then
joined directly to the contact-plates by soldering. By these means, a porcelain or
like solid base may be employed in the cap.

page_text: Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
1. In the manufacture of incandescent electric lamps, securing the cap to the bulb
by means of solder or other fusible metal or alloy introduced in a liquid state and
occupying a hole in the cap and a cavity or dent in the neck of the bulb, substantially
as described.
2. In the manufacture of incandescent electric lamps, securing the leading-in
wires by soldering the same directly to the contact-plates of the lamp-cap, sub-
stantially as herein described, whereby the employment of special wires are dispensed
with, and the use of a porcelain or like solid base is rendered practicable.
Dated this 18th day of November 1896.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.