IMPROVEMENTS IN MOULDS FOR MOULDING OR SHAPING BULBS FOR INCANDESCENT ELECTRIC LAMPS AND OTHER ARTICLES OF GLASS
Year: 1883

page_text: LETTERS PATENT to Alfred Swan of the Borough of Gateshead in the County
of Durham Engineer for an Invention of "IMPROVEMENTS IN MOULDS FOR
MOULDING OR SHAPING BULBS FOR INCANDESCENT ELECTRIC LAMPS AND
OTHER ARTICLES OF GLASS
ע
PROVISIONAL SPECIFICATION left by the said Alfred Swan at the Office
of the Commissioners of Patents on the 8th February 1883.
ALFRED SWAN of the Borough of Gateshead in the County of Durham Engineer
"IMPROVEMENTS IN MOULDS FOR MOULDING OR SHAPING BULBS FOR INCANDESCENT
ELECTRIC LAMPS, AND OTHER ARTICLES OF GLASS
"
"The object of my Invention is to provide a mould for moulding or shaping bulbs
for incandescent electric lamps or other articles of glass, in which moulds such
articles can be blown more perfectly than hitherto without mould marks, or with
but little mould marks, that is to say, marks in the glass at the parts corresponding
to those at which the junction of the portions of the mould occur
In constructing a mould according to my Invention I form it in three parts
viz-a bottom part forming the lower portion of the mould, and two top parts
forming together the upper portion of the mould.
The bottom part is in one piece, and has an inclined upper surface. To this
bottom part the two top-parts are hinged, they being formed with lower surfaces
corresponding to the inclined upper surface of the bottom part of the mould-The
top parts are each provided with handles or other means for opening out the said
top parts clear of the bottom part. The parts of the mould may be made of any
suitable material, but they are preferably made of plumbago or carbon agglomerate
encased in iron or of steatite or soapstone encased in iron. The parts of the mould
being closed into position, the glass is blown and rotated therein, and owing to the
herein before described arrangement and formation of the parts, the lower part
being without joint and the lateral division being inclined, the articles when
released from the mould, by opening out the top parts, will be found free or nearly
free from mould marks.

page_text: "
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alfred Swan in the Great Seal Patent Office on the 8th August
1883.
ALFRED SWAN of the Borough of Gateshead in the County of Durham, Engineer,
IMPROVEMENTS IN MOULDS FOR MOULDING OR SHAPING BULBS FOR INCANDESCENT
ELECTRIC LAMPS AND OTHER ARTICLES OF GLASS
"
The object of my Invention is to provide a mould for moulding or shaping bulbs
for Incandescent Electric Lamps or other articles of glass, in which moulds such
articles can be blown more perfectly than hitherto without mould marks or with
but little mould marks, that is to say, marks in the glass at the parts corresponding
to those at which the junction of the portions of the mould occur. In constructing
a mould according to my Invention I form it in three parts, viza bottom part
forming the lower portion of the mould and two top parts forming together the
upper portion of the mould.
The bottom part is in one piece and has an inclined upper surface. To this
bottom part the two top parts are hinged they being formed with lower surfaces
corresponding to the inclined upper surface of the bottom part of the mould. The
top parts are each provided with handles or other means for opening out the said
top parts clear of the bottom part. The parts of the mould may be made of any
suitable material but they are preferably made of plumbago or carbon agglomerate
encased in some suitable material preferably iron, or of steatite or soapstone encased
in some suitable material preferably metal. The parts of the mould being closed
into position the glass is blown and rotated therein, and owing to the herein before
described arrangement and formation of the parts the lower part being without
joint and the lateral division being inclined the articles when released from the
mould by opening out the top parts will be found free or nearly free from mould
marks.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheet of drawings the same letters of reference
indicating corresponding parts in all the figures.
Figure. 1 is a side elevation of a mould (in its closed position) constructed
according to my Invention for moulding bulbs or globes for incandescent electric
lamps.
Figure 2 is an elevation of the said mould shewing one of the top parts opened
out and the bottom part in section.
Figure 3 is a plan shewing the top parts fully open out clear of the bottom part.
The mould is made in three parts A A A the bottom part A being in one piece
and the top parts A³ A³ are connected thereto by a hinge pin B passing through
lugs a formed on the said top parts which are each provided with a handle C so as
to facilitate their being closed over the lower part A and opened out therefrom.
The outer part or casing D of the mould may be of metal or wood whilst the inner
part E, for imparting to the article to be moulded the desired form, may consist of
any suitable material but it is preferred to employ plumbago or carbon agglomerate
or steatite or soapstone for the purpose.
The upper surface of the lower portion A of the mould has an inclined surface as
shewn, and the under surface of each of the top parts A2 A³ are similarly inclined
so that when the mould is closed as shewn in figure 1 the line of division between
the bottom part A and the two top parts A2 A3 will be at an angle to the base of
the mould, and at an angle other than a right angle to the axis of rotation of the

page_text: article being moulded. The article to be moulded is produced by blowing the glass
into the mould in its closed position and rotating it at the same time in the mould
which may be effected in the usual manner but by constructing the mould in the
manner described it is obvious that by reason of the bottom part of the mould
being in one piece and the junction of the mould being inclined to the axis of
rotation, the moulded article will be free or nearly free from mould marks.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is:-
First: The mould for moulding or shaping bulbs for incandescent electric lamps
or other articles of glass, the said mould being constructed with a bottom part in
one piece and with an inclined upper surface, and with separate top parts similarly
inclined on their under surfaces substantially as hereinbefore described and
illustrated in the accompanying drawings.
Second: In moulds for moulding or shaping bulbs for incandescent electric lamps
or other articles of glass the combination of a bottom part in one piece with
divided top parts capable of being closed over the bottom part to complete the
mould and opened out therefrom to release the moulded article, substantially as
hereinbefore described with reference to the accompanying drawing
In witness whereof I the said Alfred Swan have to this my Specification set
my hand and seal this seventh day of August One thousand eight hundred and
eighty-three.