Improvements in and relating to Electric Incandescent Lamps.
Year: 1896

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 11 of the Patents, &c., Act, 1883), as required by
the decision of the Comptroller General of the 18th day of March 1897.
Date of Application, 17th Jan.. 1896
PROVISIONAL, SPECIFICATION.
Improvements in and relating to Electric Incandescent Lamps.
I CHARLES JOHN PEACH ROBERTSON, Manager, of The Incandescent Electric Lamp
Company Limited, Manufacturers of Electric Lamps, of Brook Green Works,
Hammersmith, London, W., do hereby declare the nature of this invention to be as
follows:-
This invention relates to the securing of electric incandescent lamps to their caps
without the use of plaster or other material that is capable of taking up moisture,
which has a deleterious effect, as will be well understood.
Attempts have been made to obviate these difficulties, and with more or less success,
but in most cases the cost of the fittings has been considerably increased, either from
the complicated nature of the fittings, or from the nature of the labour required to
ensure the proper accuracy in fixing the fittings to the lamps, and the object of my
invention is to provide simple, fittings, and so to fix the fitting to the lamp, as to
overcome these disadvantages.
In carrying out my invention, I adapt to the lower end or neck of the bulb, a ring
having two or more studs or projections externally, which ring may be secured to the
neck by softening and blowing out the neck above the ring. Or I may bend inwards
portions of the ring, so that they will, when pressed onto the bulb, make and lie in
depressions in the softened glass, the outside pins or projections being also employed.
These external pins or projections are intended to take into, or engage with, inclined
slots in a cap carrying the contact plates, and they are secured, when fixed in position,
by a small dab of solder. Or I may solder the cap directly to the ring, holes or slots
being made in the cap through which the solder can reach, and join onto, the ring.
Or I may employ a flat ring alone, or as a flange to the other ring, which is put
onto the bulb, and retained by bulges formed by blowing out, as before mentioned, or
in any other convenient manner. This flat ring or flange will be provided with holes
by which it can be screwed to an insulated plate carrying the contact plates, and
contained in a suitable cap, or it may be secured by screws to an external flange of
the cap.
Or I may employ an externally threaded ring, which will be screwed into an
internally threaded cap, and then secured by a dab of solder.
In all these cases where a ring is used, I form recesses in the edge, into which the
glass of the bulb will be blown, and thus the ring will be prevented from rotating in
the lamp bulb. It will be obvious that the rings may be secured in place by means
of a small stud of glass or platinum melted on to the bulb.
In some cases, I may find it desirable to secure the caps direct to the bulb by
previously preparing the latter with a ring or coating of pure silver, or other suitable
noble metal, mixed with some substance of a resinous nature or derivation, such as
Canada balsam or turpentine, and soldering the cap thereto.

page_text: The glass projections may also be coated with the noble metal mixture, and soldered
in the bayonet slots of the cap.
The caps may be formed with straight slots from the edge downwards, into which
the projections on the lamp bulb or ring are inserted, and secured by screwing
on a ring.
By the above named means of securing the caps, the caps will be drawn down
tight onto the shoulder of the bulb, which will thus be securely held in position, and
the necessity for expensive labour will be avoided.
Dated this 17th day of January 1896.
NEWTON & SON,
Agents for the Applicant.
Improvements in and relating to Electric Incandescent Lamps.
I CHARLES JOHN PEACH ROBERTSON, Manager of The Incandescent Electric Lamp
Company Limited, Manufacturers of Electric Lamps, of Brook Green Works,
Hammersmith, London, W., 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 the securing of caps to electric incandescent lamps without
the use of plaster or other material capable of taking up moisture, as moisture on or
in the fittings has a deleterious effect, as will be well understood.
Attempts have been made to obviate these difficulties, and with more or less
success, but in most cases the cost of the fittings has been considerably increased,
either from the complicated nature of the fittings, or from the nature of the labour
required to ensure the proper accuracy in fixing the fittings to the lamps; and the
object of my invention is to provide simple fittings, and so to fix the fittings to the
lamps, as to overcome these disadvantages.
In the accompanying drawings, I have shown various plans whereby this invention
can be carried into effect, the several figures being referred to in describing the
various plans.
In carrying out my invention, I may, among other plans, adapt to the lower end or
neck of the glass bulb, a ring provided with external studs or projections, which studs
or projections are intended to take into curved or straight notches in the cap, to be
secured therein by solder, or in any other convenient manner.
One form of the ring which I may employ is shown in perspective at Fig. 1,
A indicating the ring, a the locking studs or projections, and a¹ notches or
recesses.
In order to secure the ring A to the bulb, which may be effected in various ways
the ring may be first fitted onto the neck of the bulb, which will then be softened
with the blow pipe; the softened glass will then be blown out, so that the glass will
be caused to enter and fill up the notches a'.
Instead of blowing, the glass may be pressed out into the notches a¹ by means of
a tool or metal point inserted inside the glass neck when the latter is hot, and during
the operation of forming the neck in the manner well understood. By this means,
the ring A will be secured to the bulb, as will be seen at Fig. 2, the letter X indi-
cating the bulb of the incandescent electric lamp.
B is the cap (shown in perspective at Fig. 3), which is provided with the usual
external studs or projections 6, to take into the bayonet slots of the socket of the
electric lamp fittings in the well-known manner, and is also formed with notches or
slots 6, which are preferably straight, as shown at Fig. 3, but may be curved or
inclined, as shown at Fig. 4.

page_text: The studs a of the ring A, when the cap is applied, will enter the slots b' of the
cap B. The cap is pressed well down onto the shoulder of the bulb X, and is secured
to the ring A or the studs a by a dab of solder, as shown at Fig. 2.
With the inclined slots b', Fig. 4, a slight axial motion will draw the cap down
onto the shoulder of the bult X, when it is secured, as before, by a small dab
of solder.
Instead of securing the ring A to the neck by blowing out or forcing out with a
tool a portion of the neck, as described, I may apply to the bulb two little pins or
projections of molten glass a³, one in each corner of the notch a', as shown in the side
view at Fig. 5.
In some cases, I may prefer to turn or bend inwards portions of the ring A, as seen
at a in the plan view, Fig. 6, and side view, Fig. 7. These projections will lie in
depressions formed by blowing out the softened glass around them."
I may also form, in any convenient manner, studs or projections on the inside of
the ring, which will also lie in depressions formed by blowing the glass, when in a soft
state, around them.
In order to ensure a firm and rigid connection of the cap B with the bulb X, I may
form the ring A with notches a in the lower edge, in addition to the notches a¹ or
projections a (see the side view Fig. 8). The ring A may be secured to the bulb as
before described, or in any other convenient manner. The cap B will be formed with
vertical slots or holes 2, in such a position as to correspond with the notches a³, when
the cap B is placed over the ring (see the side view Fig. 9). The cap B being placed
in position on the ring A when the lower ends of the slots 62 of the cap B are just
clear of the bottoms of the notches as of the ring A, a pointed instrument will be
inserted, so as to lever the cap B down onto the shoulder of the bulb, and the ring A
up against the projections or other parts in the bulb. Solder is then applied in or
about the slot or hole, or in any other part, so as to solder the ring and cap rigidly
together, and thus a firm and rigid connection is made.
In adapting the ring A to bulbs in which depressions 6 have been formed in the
neck (see the partial sectional elevation Fig. 10), as is the case in bulbs which are
secured by plaster of Paris to the cap, I may employ a divided spring ring (see the
plan view Fig. 11), having on the inner side studs, projections, or pins c, of solder or
other metal, which will be arranged so as to fit into the depressions 6*. This divided
ring is placed on the neck with the pins c in the depressions *, and is closed up, and
the cap B is then placed over it. The ring will thus be firmly held by the cap, and
the cap will be soldered to the ring, or secured in any other convenient manner.
The
ring may be formed with notches a³, as in Figs. 8 and 9, and the cap may be levered
down and secured in the manner described with reference to those figures.
Fig. 12 is a side view of the notched divided or spring ring A, and Fig. 3 is
a similar view, partly in section, showing the application of the slotted cap B
thereto.
Instead of forming projections on the ring, I may make them on the glass bulb
(see the side view, Fig. 14) by blowing out, or adding a pin or, stud of molten
glass, as before mentioned, holes being formed in the ring, as seen in perspective.
at Fig. 15, to receive them. When the parts are put together, they will appear as
illustrated in the partial sectional view, Fig. 16.
When employing a solid ring with holes, I may make the holes so as to corre-
spond with the depressions formed, as before described, in the bulb, and I drop in
a metal pin, which will be soldered to the ring (or the pin may be formed with
the solder), and thus the ring may be secured to the bulb. The cap B may be
provided with the slots 62, and levered down, and secured to the ring A in the
manner described with reference to Figs. 9 and 13.
In some cases, I may find it desirable to secure the cap direct to the bulb, for
which purpose the cap is formed with a number of holes near its lower edge, through
which solder is run onto a prepared surface. This surface will consist of a ring or
coating of pure silver, or other suitable noble metal, mixed with some substance of
a resinous nature or derivation, such as Canada balsam or turpentine, which is painted

page_text: onto the bulb, and burnt into the substance of the glass by the application of heat.
This is most conveniently done concurrently with the necessary heating required at
the same spot when "sealing-in" the filament in the well known method. To prepare
this mixture, I take pure precipitated silver, as used by potters, for glass or china
decoration. This fine, impalpable powder is mixed in a mortar, or preferably on a
muller, with sufficient Canada balsam to give a thick cream, which should contain
as much silver as possible. The finer the powder and the more intimate the mixture,
the better is the result. Trials can be made of the mixture by painting some onto
pieces of glass, and heating same in a Bunsen buruer to various intensities, and
then, when cool, trying with a knife or other sharp tool, whether the silver is
thoroughly attached to the glass. Once mixed in the proper proportions, the
mixture will remain good indefinitely, and will only require thinning down
occasionally, by stirring it with a little turpentine, or thin Canada balsam, or both.
For a plain-necked bulb, I find that at least three holes are necessary, and if no
more are employed, the metal coating need only be applied to the bulb at corre-
sponding points, as indicated in the side view, Figs. 17.
When a bulb with studs or projections is used, I may coat the studs or projections
only with the metallic coating, and solder to these coated projections through the
holes in the cap, as shown in the sectional view Fig. 18. The cap may be made
so as to spring over the projections in any well-known manner.
The cap may be formed with internal projections, spring or otherwise, and placed
on the softened neck, which may then be blown out round the projections, as before
explained, solder being used, if and when necessary, to secure the parts.
I may also secure the cap direct to the bulb by means of short-headed pins,
which I insert, from the inside or outside the cap, through holes therein, and
I then place the cap over the neck of the bulb, which has been previously provided
with depressions, as shown in the sectional view Fig. 20, and into these depressions
the pins are pushed, and, being held in position, are affixed to the cap with solder.
When a bulb X with projections is to be fitted to a cap B, I form the studs on
the bulb opposite the holes in the cap, and I insert in the holes short pieces of fine
tube or thin sheet brass rolled up, which fit onto the projections, and are soldered
to the cap.
This arrangement is shown in the sectional view Fig. 21, c¹ el repre-
senting the short pieces of tube, or the caps may be made to spring over the
projections, and are afterwards secured by solder in any convenient manner.
In the same figure, I show means for ventilating the cap, which consists of
holes d d formed about the centre of the length of the cap, and a hole d' formed in
the insulating plug f, which closes the end of the cap in the well-known manner.
It will be understood that all the caps may be provided with these holes and
insulating plugs, although they are not shown in the other figures.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The means, as herein shown and described, for attaching or securing caps to the
bulbs of incandescent electric lamps without the aid of plaster, or other moisture-
absorbing material, as set forth.
Dated this 11th day of August 1896
NEWTON & SON,
Agents for the Applicant.