A New or Improved Frame of Porcelain or other Ceramic Material.
Year: 1899

page_text: Date of Application, 7th June, 1899-Accepted, 2nd June, 1900
COMPLETE SPECIFICATION.
"A New or Improved Frame of Porcelain or other Ceramic Material.
I, REINHOLD SCHLEGELMILCHI, of Suhl, Thuringia, Germany, 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 ceramic industry the manufacture out of porcelain, or other analogous
materials, of frames in one piece, of comparatively large dimensions for pictures,
looking glasses and other similar objects has not hitherto been accomplished.
Frames of this kind have hitherto been moulded solid and in several pieces
and united after the baking process by glueing or cementing or other suitable
and well known methods of fastening.
The present invention relates to the manufacture of hollow frames in one piece
by casting the paste. By this means a frame is produced both lighter and more
resistant to any deformation and cracking during the process of baking.
As already mentioned, frames and articles of the kind referred to have up to
the present time been manufactured by pressing a plastic mass into a single
mould of the shape of a semi-tube. By my invention such a frame is manu-.
factured by casting or pouring a liquid paste in a pair of double moulds forming
a closed tube.
By my method of casting one obtains the great advantage of a perfect homo-
geneity of the paste which during the drying as well as during the process of
baking becomes absolutely resistant against any deformation..
It has already been recognized that a tube of any material whatever possesses
à greater resistance than a solid object of equal mass. By my invention I
obtain frames or other similar objects of tubular shape and absolutely uniform
in mass or texture and of porcelain or other ceramic material in one single piece
without injury to their shape during the manufacture.
In the drawing one portion of such a frame is represented, Figure 1 being a
front view and Figure 2 a transverse section.
The constructional form chosen by way of example in the present description
comprises a face affecting the shape of any desired ornamental configuration
and a rear face or back with plane surfaces, stepped or set off as at a, c, the
receding portion a of which serves to receive the mirror or the picture. These
three surfaces constitute the cover or jacket of the hollow space.
The portion is provided with several holes arranged in a suitable manner
so as to permit of the frame being. hooked.
The front surface may be of any suitable shape either ornamented or smooth
and may be decorated in
any colours.
Frames manufactured in accordance with my invention being much lighter
and being less liable to deformation or cracking during the baking process than
those made by other methods may be made of much greater dimensions than
heretofore.
I cast moulds and flat plates in plaster of Paris or other suitable hygroscopic
material and I dry the moulds upon the perfectly flat plates of plaster of Paris
in order to prevent warping.

page_text: The hygroscopic material of which the moulds are made absorbs moisture very
rapidly so that the porcelain slip poured into them immediately adjacent to the
surface of the moulds thickens or sets rapidly into a plastic state. When a suffi-
cient thickness of porcelain slip has set in the mould the superfluous slip may
be poured off leaving a hollow moulded frame of porcelain ready for drying and
fixing in a kiln.
In the case of frames of comparatively large size as the moulds are heavy 80
as not to admit of being manipulated it is necessary to use a specially con-
structed table to facilitate turning and tilting or tipping when it is desired to
pour off superfluous slip. I use a casting table constructed to turn and tip or
tilt on a central device such as a ball and socket joint and I securely fasten the
heavy plaster moulds to the table by screws or other suitable devices."
The moulds consist of two main portions hereinafter called the "front mould"
and the "back mould " one in which the front or ornamental portion of the
frame is moulded, and another in which the back of the frame is moulded with
a rebate to receive pictures glass or the like. The rear wall of the back mould
has two or more openings through which the liquid porcelain or slip is poured.
In order to ensure that the thickness of plastic porcelain deposited upon the
faces of the moulds may be uniform, the back mould should first have sufficient
slip deposited in it to produce the requisite thickness of the frame.
After this preparatory work moulds are filled up with slip and then after the
lapse of a sufficient time to ensure the deposition or setting of sufficient thick-
ness of porcelain the superfluous slip is poured off from the moulds by tilting
the table upon which the moulds are fastened.
When the plaster moulds have withdrawn from the soft frame sufficient mois-
ture to bring the slip to the hardness of leather, the back mould is removed and
the frame is provided with the required openings for fixing the pictures and
ears for suspending the frame. The frame is now removed from the front
mould and placed upon a level and freshly cast plate of porcelain material
which has been previously covered with strips of parchment paper. The porce-
lain plate which now itself begins to shrink, is intended to support the frame in
its shrinking, and as the hollow frame is subject to greater shrinkage than its
solid base as support, the object of the parchment paper is to prevent the sup-
port and the frame sticking together.
After the frame has been completely dried it is baked in a kiln of masonry
and then glazed upon its face only so, that its weight may be kept down as
much as possible.
As it has not so far been possible to manufacture muffles or cases of fire-proof
brick of sufficient resistance to stand the heat of a kiln or furnace for burning
hard-porcelain, and of sufficient dimensions to receive a picture frame, I make
a muffle for the porcelain frame into which the frame is inserted. This muffle
is provided with outer and inner walls to prevent the collapse of the muffle.
In order to prevent the collapse or sinking in of the top of the muffle it is
constructed so as to correspond with the contour of the frame as represented in
Figure 5, that is to say its section just suffices to contain the frame and at its
centre it is hollowed in such a fashion that the interior walls b and exterior
walls a strengthen the muffle so as to prevent the sinking in of the upper part.
In addition to this my special construction of muffle facilitates the obtaining
of the necessary temperature for baking.
In Figure 3 which represents a section of a plaster of Paris mould for casting
a frame constructed in accordance with my invention, a, a, a, a, is the back mould,
b, b, b, b, is the front mould and c, c the openings herein before described.
Figure 4, is a section of a muffle containing a frame ready for baking and
Figure 5, is a diagrammatic perspective view of a muffle containing a frame,
partly cut away to show the frame.
In these figures a, b, is the muffle and a, the outer walls, b, the inner walls,
and E the frame.

page_text: 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 hollow frame constructed substantially in the manner herein set forth.
Dated this 7th day of June 1899.