Improvements in Forming Undercut Projections and Recesses in Tiles and other Articles of Pottery and in Apparatus therefor.
Year: 1891

page_text: Date of Application, 19th Jan., 1891
Complete Specification Left, 19th Oct., 1891-Accepted, 21st Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in Forming Undercut Projections and Recesses in
Tiles and other Articles of Pottery and in Apparatus therefor.
We, HENRY LEWIS DOULTON, Potter, and STEPHEN HENRY LEEch,
Manager, both of the Albert Embankment, Lambeth, in the County of Surrey, do
hereby declare the nature of this invention to be as follows:-
According to this invention we form undercut projections or recesses by pressing
against the clay pieces or perforated sheets of india rubber or other elastic material,
one face of which is held whilst the face next the clay spreads out laterally by the
pressure.
We proceed as follows:-We fill a mould with powdered clay as is usual.
The mould is the same as those at present employed except that on one or more of
its faces we fix projections of india rubber or other elastic material if it is desired
to make undercut holes or a sheet of india rubber having holes in it if it is desired
to make undercut projections. The mould having been filled pressure is applied
the result being that the india rubber or other elastic material spreads laterally on
its face next the clay whilst the surface which is in contact with or fixed to the side
of the mould remains at rest or nearly so. Thus in the case of projecting pieces
their faces next to the clay become broader than their faces next to the mould, and
in the case of holes in a sheet the diameter of the hole next to the clay becomes
smaller than the diameter of the hole next to the mould, and undercut holes or
projections respectively are formed in the clay. When the pressure is relieved,
the india rubber or other elastic material resumes its former shape, which facilitates
delivery.
D
fan1901
H. L. DOULTON.
STEPHEN HENRY LEECH.
COMPLETE SPECIFICATION.
Improvements in Forming Undercut Projections and Recesses in
Tiles and other Articles of Pottery and in Apparatus therefor.
We, HENRY LEWIS DOULTON, Potter, and STEPHEN HENRY LEECH,
Manager, both of the Albert Embankment, Lambeth, in the County of Surrey, 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:
According to this invention we form undercut projections or recesses by pressing
against the clay pieces or perforated sheets of india rubber or other elastic material,
one face of which is held whilst the face next the clay spreads out laterally by the
pressure.
We proceed as follows: We fill a mould with powdered clay as is usual. The
mould is the same as those at present employed except that on one or more of its
faces we fix projections of india rubber or other elastic material if it is desired to
make undercut holes or a sheet of india rubber having holes in it if it is desired to
make undercut projections. The mould having been filled pressure is applied the
result being that the india rubber or other elastic material spreads laterally on its
face next the clay whilst the surface which is in contact with or fixed to the side of
the mould remains at rest or nearly so. Thus in the case of projecting pieces their
faces next to the clay become broader than their faces next to the mould, and in
the case of holes in a sheet the diameter of the hole next to the clay becomes
smaller than the diameter of the hole next to the inould, and undercut holes or

page_text: projections respectively are formed in the clay. When the pressure is relieved, the
india rubber or other elastic material resumes its former shape, which facilitates
delivery.
In order that 'our said invention may be fully understood and readily carried into
effect we will proceed to describe the drawings hereunto annexed.
In order that 'our said invention may be fully understood and readily carried into
effect we will proceed to describe the drawings hereunto annexed.
DESCRIPTION of the DRAWINGS.
Figure 1 is a front elevation, and
Figure 2 is a side elevation of the apparatus we employ.
Figure 3 is a back elevation of a tile produced according to our invention, and
Figures 4, 5 and 6 are sections to a larger scale of the mould and plunger in
different positions.
The press shewn is a screw press of ordinary construction, it is provided with a
mould box A held down to the bed by bolts A', in this mould box there is a
follower B actuated by a spindle B' and lever B. C is a filling piece or die placed
upon the follower B, its upper surface may be engraved so as to produce a pattern
upon the tile in the ordinary manner. E is the plunger of the press and bolted to it
is a compound plate F upon whose face are blocks G of india rubber or other
elastic material. The compound plate is made by brazing together a plain plate
and a plate with taper holes in it, as shewn, to receive the blocks of india rubber
which are forced into them.
Or the india rubber blocks G may be attached to a plain plate by cement or a
plate of vulcanite may be used with the blocks of soft rubber moulded upon it.
The portion of the mould above the plate C having been filled with powdered
clay H, as shewn in Figure 4, the plunger is forced down and the pressure causes
the blocks G to swell laterally producing undercut recesses in the clay as shewn in
Figure 5.
The plunger E is then raised as shewn in Figure 6, and then the follower B and
the compressed tile is removed. As the pressure is relieved the blocks G resume
their original shape and therefore withdraw from the undercut recesses without
breaking the edges. These undercut recesses give a good key to the cement used
in setting the tile.
We lay no claim to the mechanism of the press shewn in the drawings which is
of ordinary construction, the novelty lying in the application and use of the
blocks G on the face of the plunger E. It must also be understood that we do not
limit ourselves to any particular shape for the blocks G which, in place of being
discs, as shewn, may be in the form of letters or designs; or, as above explained, a
single sheet with holes of the desired contour in it. In place also of the blocks G
being upon the plunger E they may be upon the follower or both upon the plunger
and follower so as to produce undercut recesses or prominences upon both faces of
the tile or other article.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. The process of forming undercut projections and recesses in tiles and other
articles of pottery by pressing pieces or perforated sheets of india rubber or other
elastic material upon or against the clay from which such articles are made whilst
the same is confined in a mould.
2. A mould for producing tiles or other articles of pottery having upon one or
more of the interior surfaces thereof pieces or perforated sheets of india rubber or
other elastic material so arranged as to produce undercut projections and recesses
on one or more of the surfaces of the tile or article.
Dated this 19th day of October 1891.
H. L. DOULTON.
STEPHEN HENRY LEECH.