Improvements in the Manufacture of Incandescent Electric Lamps.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Incandescent Electric Lamps.
We, WILLIAM EDWARD BARRAS, of 8, Durant's Villas, Ponders End, in the
County of Middlesex, Glass Blower, and HENRY CHARLES GOVER, Secretary of the
Edison & Swan United Electric Light Company Limited, of 36 and 37, Queen
Street, Cheapside, London, E.C., do hereby declare the nature of this invention
to be as follows:-
This invention has reference to the manufacture of glass bulbs for incandescent
electric lamps.
We make such a bulb partly of opal and partly of ordinary flint glass or
coloured glass. A piece of molten opal is taken from a pot or crucible on the end
of a blow iron, and by marvering or rolling, blowing and swinging, the opal is
converted into a kind of tubulous form with one closed end, a part of which latter
is then formed into a knob, above which an annular groove is formed, after which
the knob, with the portion of opal between itself and the annular groove is removed
from the tube, which is then open-ended. The open end thus formed is then
heated and converted by blowing into a small bulb, the closing of the open end
being prevented by a stopper.
Then, on the end of an iron, a piece of molten flint glass or crystal or coloured
glass (according to requirement) is taken, and is, by means of tongs, formed into
a disc or button-like piece, which is then inserted into the already-mentioned hole
in the opal bulb, so as to close that hole.
Then the whole is highly heated, and by blowing, the bulb is slightly enlarged,
after which it is inserted into a mould made in parts, of any suitable material,
such as wood, iron, carbon, or brass, of an internal formation corresponding to
the external shape to be given to the finished bulb, and whilst thus in the mould
the bulb is further blown up, and simultaneously rotated within the mould.
The process described results in the formation of a bulb with a neck, the neck
and adjacent portion of the enlargement or bulb proper being of opal, and the
remainder of the bulb of flint or crystal or coloured glass, as the case may be;
if, instead of taking opal in the first instance, ordinary flint or crystal or coloured
glass be taken, the disc or button-like part being formed of opal, then the process
will result in the formation of a bulb whose neck with the adjacent portion of the
bulb proper will be of ordinary flint or crystal or coloured glass, the remainder
being of opal.

page_text: Improvements in the Manufacture of Incandescent Electric Lamps.
fj
We, WILLIAM EDWARD BARRAS, of 8, Durant's Villas, Ponders End, in the
County of Middlesex, Glass Blower, and HENRY CHARLES GOVER, Secretary of the
Edison & Swan United Electric Light Company Limited, of 36 and 37, Queen
Street, Cheapside, London, E.C., 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:-
Thissinvention has reference to the manufacture of glass bulbs for incandescent
electric lamps of a kind referred to in the Specification of Patent No. 1591 of
1897.
According to the present invention such a bulb partly of opal and partly of
ordinary flint glass or coloured glass, is made as we will now proceed to explain
by the aid of the accompanying illustrative drawings the several figures of which
show partly in side elevation and partly in section the several stages of manu-
facture.
A piece 1 of molten opal (Fig. 1) is taken from a pot or crucible on the end of
a blow iron 2, and by marvering or rolling, blowing and swinging, the opal is
converted into a kind of tubulous form 1 (Fig. 2) with one closed end a part of
which 'latter is then formed into a knob 3 (Fig. 3), above which an annular
groove 4 is formed, after which the knob, with the portion of opal between itself
and the annular groove is removed from the tube 1ª, which is then open-ended.
The open end thus formed is then heated, as by inserting it in a glass furnace,
and converted, by blowing, into a small bulb 1b (see Fig. 4), the closing of the
open end being prevented by a taper stopper 5 of suitable material such as glass
which is held in the hole so as to temporarily close it during the blowing to form
the small bulb and to enlarge it to the extent shown in Fig. 5. Then, on the end
of an iron, a piece of molten flint glass or crystal or coloured glass (according to
requirement) is taken, and is, by means of tongs, formed into a disc or button-
like piece 6 (Fig. 5), which whilst soft and sticky, is then inserted into or applied
to the edge of the already-mentioned hole in the opal bulb 1b so as to close that
hole and adhere closely all round to the edge portion thereof.
Then the whole is highly heated,, and by blowing, the bulb is further enlarged
as shown in Fig. 6, after which it is inserted into a mould 7 (Fig. 7) made in
parts, of any suitable material, such as wood, iron, carbon, or brass, of an internal
formation corresponding to the external shape to be given to the finished bulb,
and whilst thus in the mould the bulb is further blown up and simultaneously
rotated within the mould.
The process described results in the formation of a bulb with a neck 1º, the neck
and adjacent portion 1d of the enlargement or bulb proper being of opal, and the
remainder 1° of the bulb of flint or crystal or coloured glass, as the case may be.
If, instead of taking opal in the first instance, ordinary flint or crystal or
coloured glass be taken, the disc or button-like part 6 being formed of opal, then
the process will result in the formation of a bulb whose neck with the adjacent
portion of the bulb proper will be of ordinary flint or crystal or coloured glass.
the remainder being of opal.
As already indicated the internal shape of the mould will depend upon the
precise external formation. of bulb it may be desired to produce.

page_text: Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed we declare that what
we claim is :-
The manufacture substantially in the manner hereinbefore described with refer-
ence to the accompanying illustrative drawings, of glass bulbs for incandescent
electric lamps such bulbs being made partly of opal and partly of ordinary flint
glass or crystal or colored glass as set forth.
Dated this ord day of February 1890.
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.