An Improved Mode of and Apparatus for the Manufacture, in Glass, of Letters, Figures, and other Devices.
Year: 1895

page_text: Date of Application, 3rd Jan., 1895-Accepted, 9th Feb.,
1895
COMPLETE SPECIFICATION.
An Improved Mode of and Apparatus for the Manufacture, in Glass,
of Letters, Figures, and other Devices.
I PAUL SIEVERT of 32 Linden-austrasse, Dresden in the Kingdom of Saxony.
(German Empire), Glass Manufacturer, 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 :-
In the Specification of the British Patent No. 17848 of 6th October 1892, I
described a process for manufacturing flat objects of glass, consisting mainly in
pressing or rolling down molten glass into a sheet, and stamping into the same,
while still in a plastic condition, the contours of the objects to be produced,
The process was
which were then to be separated by breaking up the sheet.
attended with the disadvantage that the natural brilliancy of the molten glass
was diminished by contact with the bed upon which it was rolled.
Now the object of the present invention is to remove this disadvantage, and
to retain the natural brilliancy of the glass on both sides of the moulded
articles. To this end, instead of rolling the glass, I effect the indentation or
shaping of the contours of the objects to be produced, by means of the glass
blowing process, using, in combination therewith, a mould formed of detached
parts, and faced with cutting or indenting edges representing the contour of the
articles to be moulded.
Into the open mould thus provided, the molten glass is placed by the glass
blower, who then closes the mould, and, by blowing into the imprisioned bull of
molten glass, expands it sufficiently to bend over the cutting or indenting edges of
the mould, without touching the face thereof. In this way, a hollow glass body
will be formed, the inner and outer surfaces of which will retain the natural
lustre of the glass, showing, by indents on the outer surface, the contour of the
devices desired, which devices may be separated by breaking up the hollow glass
body, and subjecting the raised lines to a grinding process.
It is well to choose the shape of the hollow glass bodies so that they present
even sheet surfaces or walls of considerable size for the indenting of the contours
into such sheet surfaces, and that the connecting lines of such surfaces or walls
may be easily severed, for the purpose above stated.
In the accompanying drawing I have shown two forms of glass bodies which
may be conveniently adopted in carrying out my improved moulding process.
Fig. 1 is a perspective view of a cube of glass indented by the glass blowing
process, designed to be cut up or separated into its single sheet surfaces or walls,
which are then to be so treated as to separate the different outlined objects,
which separation may be effected, for instance, by subjecting the sheet surfaces at
the rear side to a grinding process, until the attaching portions of the glass are
wholly, or in great part, removed.
Figs. 2 and 3 show in front view and cross section, a hollow glass body, the
parallel sides of which are indented with the contour of the devices designed to
be produced.
Fig. 4 shows in vertical section one side of a mould, having on its inner face
indenting or cutting edges designed to represent the contour of the articles
These
required to be formed in the mould by the glass-blowing process.

page_text: indenting edges may be cast with the side of the mould, or in place of making
them in one with the mould side, they may be formed separate therefrom, and
secured in place by screws, as illustrated in the section Fig. 5; the advantage of
this latter plan is that the indenting edges are removable, and may be replaced
by various indenting figures, according to the requirements of the workman, the
same mould thus serving for varieties of work.
Fig. 6 shows in section a portion of the side of a mould fitted with cutting
or indenting contour projections, and having pressed thereon the glass to be
moulded.
The face of the glass next the mould, it will be seen, is held from contact with.
the mould surface by means of the indenting edges fitted to the face of the mould,
and it is by regulating the pressure of the air delivered to the hollow body of
glass, so as to stop its expansion before reaching the face of the mould, that the
result indicated by the diagram is secured.
The six inner faces of the mould used to produce the glass body shown at Fig. 1,
are similarly provided with cutting or indenting contour projections, which, by
arresting the expansion of the glass under the air pressure, will allow of the
bulging of the glass, without, as before stated, touching the face of the mould.
In this way all the six sides of the cube will receive indents of the contours of
the objects to be produced.
.
When the blowing process is completed, and the glass is set, the closed
mould is opened, and the cube of glass removed from it, after which the cube is
to be subjected to an annealing process.
When annealed, the euhe is divided into its six surfaces, sheets, or plates, at the
12 lines of uniting angles.
The separated 6 plates may be treated in any well known manner, to break
them up, and separate the letters or other devices composing the plates.
The mould or form may be so constructed that the joining lines of the surfaces of
the hollow glass body become as thin as possible, so that the disconnection of the
hollow glass body may be performed in an easy, quick, and safe manner.
The glass body illustrated by Figs. 2 and 3, mainly consists of two large flat
sides with very little air room within. These flat sides are capable of receiving
impressions of the contour edges in the glass-blowing process to a considerable
extent, while comparatively little air is wanted for expanding the glass in the
mould; the joining lines of these two sides are easily disconnected, to obtain the
flat sheets or plates, which may be broken up, as explained, to obtain the several
objects or devices contained in the plates.
It should be understood that I do not confine myself to the two shapes of hollow
glass bodies illustrated for carrying out my process, for I may make use of bodies
of other convenient shapes, though shapes offering extended surfaces will always
be preferable.
For carrying out the glass blowing process, I may employ moulds with solid
walls, as illustrated at Fig. 4, or with perforated walls. Or the projections on the
inner faces of the walls of the moulds may be made detachable, as illustrated at
Fig. 5, thus, providing for (as above mentioned) the employment of one and the
same mould for producing a great variety of objects, by exchanging the profile
projections or indenting edges in the moulds for those of other forms.
This exchangeability of the indenting edges also offers this great advantage,
namely, that they may be easily sharpened, when worn or blunted in the course of
time.
As a modification of the above process, I may first make, by the glass blowing
process, a hollow glass body of the required shape in a plain mould, or mould
unprovided with indenting edges, thus producing a hollow glass body with even or
smooth surfaces.
The plasticity of this hollow glass body I may reestablish by second heating,
and submit it to the construction of mould above described, in order to form the
contour indents in the glass.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is -
-
1. The process above described for producing, by the aid of air pressure, objects
of glass in sheets, by the use of a mould provided with indenting edges or projec-
tions corresponding to the contour of the letters, figures, or devices to be produced
in the sheets.
2. For working the moulding process above described, a mould with solid or
perforated walls fitted with removable or changeable indenting edges or projections,
as and for the purpose above set forth.
100K
NEWTON & SON,
Agents, for the Applicant.