Improvements in the Manufacture of Enamel Glass Letters and other Devices.
Year: 1894

page_text: Date of Application, 15th Jan., 1894
Complete Specification Left, 14th Aug., 1894-Accepted, 20th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Enamel Glass Letters and
other Devices.
1 ERNEST BÖHM of 5 Boxworth Grove, Richmond Road, Barnsbury, London, N.
Electrical Engineer do hereby declare the nature of this invention to be as
follows:-
My invention consists of a method or methods of forming enamel glass into
letters or other devices by direct pressure, thereby avoiding the employment of
the metallic backing now generally used, and thus preventing the letters or devices
from becoming unfastened, which frequently occurs at present from the unequal
expansions at various degrees of temperature of the materials (glass and metal)
used in their composition.
In one case where I wish to form a plain letter or device, having the back level
so as to adhere closely to the window or other substance to which it may be
attached, and the front curved or in such other shape as I may wish to press the
glass into, I take a flask or bottom mould of cast iron or other suitable material,
in which the base or flat part of the letter or device is designed-but this may
also be curved-I then take a top flask or mould designed so as to give the curved
of other form of the portion of the letter above the base. The two flasks are
made to fit exactly, one over the other, so that when the letters or other devices
are formed the edges may be sharp.
Enamel glass is then poured into the bottom flask to which the upper flask is
then fitted exactly, and screwed on.
The moulds are then heated and subjected to strong pressure, the result being
that each letter or device is stamped out. These can then be attached by their
flat or curved bases to windows, sign tablets, or the like, the rounded or other
shaped faces being outside.
In another case where I wish to form my letters or devices in such way as that
an outline of the letter or device may be formed upon it in a different coloured
glass, or I inay form upon it any ornament I may wish, I take a mould consisting
of a top and bottom flask of suitable metal or material, the underside of the mould
being by preference chased out so as to form the desired outline or ornament.
The chases or grooves are then filled in with enamel glass of the requisite colour.
The upper part of the flask is then put on and the mould heated. Molten enamel
glass is now poured into the flask and the upper flask placed correctly upon it and
subjected to hydraulic or other pressure so as to cause the adhesion of the coloured
outline or ornament to the enamel glass letter or device. When raised from the
mould, the letter or device will have upon its outer surface the outline or ornament
designed. The base is by preference flat, but any desired curve can be given.
By my second method it will be noticed I form the face of my letter or device in
the lower flask.
And I sometimes form my letters or devices with the portions in the chases or
grooves before alluded to cast and pressed at the same time with the letter, all
being of the same enamel glass. I then paint the portions cast in the chases or
grooves in any colours I may desire and burn them into the surfaces of the raised
portions. I thus can obtain a double letter, one appearing to be in front of the
other, or a double letter with or without suitable ornaments or accessories.
15th Jan 1904

page_text: Improvements in the Manufacture of Enamel Glass Letters and
other Devices.
I, ERNEST BÖHM of No. 5 Boxworth Grove, Richmond Road, Barnsbury, in
the County of Middlesex, Chemical and Experimental Glass Blower, do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described in and by the following statement :—
The present invention relates to improvements in the manufacture of enamel
glass letters and other devices such as are used for purposes of advertising by
being fixed upon or to glass windows, facia boards or advertising tablets.
The material which is herein referred to as "enamel glass" is a homogeneous
compound of enamel and glass and is made by selecting and melting together the
raw materials for each accordingly.
Up to the present time, it has been found impracticable to make letters such as
are referred to above out of enamel or glass without combining a sheet metal
backing with the said letter, the purpose of such backing being to strengthen the
letter as much as the brittle nature of the material of which it is made, renders
necessary. As a consequence of the present invention, no metal backing is used
because letters made according to the said invention, are strong enough without
such backing.
Referring to the accompanying figures which are to be taken as part of this
Specification and read therewith :-
Figure 1 is an elevation from the outside of the window of a part of the latter
having one of our improved cast double solid letters fixed upon the outside of it.
Figure 2 is a vertical section along the line 2-2 of Figure 1.
Figure 3 is an elevation from the outside of the window of a part of the latter
having one of our improved cast single solid letters fixed upon the outside of it.
Figure 4 is a vertical section along the line 4-4 of Figure 3.
Figure 5 is a vertical section of part of a window having one of our improved
cast hollow backed double letters fixed upon the outside of it.
My improved letters are produced by casting the molten enamel glass in moulds
of iron or other suitable material. Such a mould is either a single flask and a
cover or a pair of flasks. A single flask and cover mould is used for a letter the
limbs of which are semicircular or less than semicircular in cross section. A
double flask mould is used for a letter the limbs of which are circular or more than
semicircular in cross section.
It is important that the mould be made hot before the melted enamel glass is
poured into it, so as to prevent the letter being cracked by the too rapid cooling
of its skin.
Referring to Figures 1, 2 and 5, the double letter illustrated therein consists of
two letters, a front and smaller limbed letter a upon a back and larger limbed
letter b. In casting a double letter, the bottom groove in the flask, corresponding
to the smaller limbed and front letter a, is filled with melted enamel glass after
which, the top groove corresponding to the back and larger limbed letter b is
completely filled up. These two pourings are necessary only when the difference
in the colours of the two letters a and b is to be produced in the mould. If
preferred, such difference may be effected in the way described further on.
When the larger groove has been poured full, the mould cover is fastened
down on to the flask, and the closed mould is subjected to severe pressure so as to
effect a perfect union between the front letter a and the back letter b.
When it is preferred to give the front letter a its final colour after the double
letter has been taken out of the mould, it is painted and the colour burnt into it in
the ordinary way.

page_text: The groove c in the back of the letter illustrated in Figure 5 is produced by
the presence on the inside face of the mould cover, of a ridge of corresponding
Cross section.
The single letter illustrated in Figures 3 and 4 is made in a single flask and
cover mould.
When a letter the limbs of which are circular or more than semicircular in cross
section is to be cast, the cavity for it is divided between the two flasks, and a gate
formed through one side or end of the mould, through which gate the melted
enamel glass can be poured, as is usual with two-flask moulds.
I do not lay any claim to the method of casting molten enamel glass or to the
use of moulds-single or double flask-for receiving the said material.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is :-
A single or a double enamel glass letter or sign without a metal backing and
made by casting melted enamel glass in a mould, as set forth.
Dated this 14th day of August. 1894.
PHILLIPS & LEIGH,
No. 22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.