Improvements in Moulds for Moulding Terra Cotta Blocks and like Articles.
Year: 1893

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Date of Application, 16th Oct., 1893
Complete Specification Left, 16th July, 1894-Accepted, 18th Aug., 1894
PROVISIONAL SPECIFICATION.
Improvements in Moulds for Moulding Terra Cotta Blocks and like
Articles.
We, HENRY LEWIS DOULTON, Potter, and JAMES MILLER CARR, Manager
of Terra Cotta Works, both of the Lambeth Pottery, Lambeth in the County of
Surrey, do hereby declare the nature of this invention to be as follows:-
-
Terra cotta blocks are at present formed in plaster of Paris moulds; the portion
of the mould which comes into contact with the clay to form the block is built up
of a number of separate slips which are held in their proper relative positions by
an outer case also of plaster of Paris, which is cast upon the slips. In the use of
the mould, when it has been filled with clay and the clay is ready to leave the
mould, the case is first removed and afterwards the slips are lifted one at a time
from the face of the block. Now these plaster mould cases are massive and
cumbersome whilst in use, and they are comparatively costly; much plaster of
Paris is used in making them and when they are done with the material is quite
useless. According to our invention we make the mould cases of a fibrous
asphalte and this material we use again and again. The fibrous asphalte is
rendered plastic or semi fluid by heat and in this state is poured upon the slips
whilst these are properly arranged around the model. An iron band may be
applied around the case to add to its strength; the band becomes partially or wholly
embedded in the plastic material. As the case cools, it hardens, and the slips can
then be removed in the same way as from a plaster case. When the mould is no
longer required the case is broken up and the material melted and re-used.
Dated this 16th day of October 1893.
H. L. DOULTON.
JAMES MILLER CARR.
COMPLETE SPECIFICATION.
Improvements in Moulds for Moulding Terra Cotta Blocks and like
Articles.
We, HENRY LEWIS DOULTON, Potter, and JAMES MILLER CARR, Manager
of Terra Cotta Works, both of the Lambeth Pottery, 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 :--
Terra cotta blocks are at present formed in plaster of Paris moulds; the
portion of the mould which comes into contact with the clay to form the block is
built up of a number of separate slips which are held in their proper relative
positions by an outer case also of plaster of Paris, which is cast upon the slips. In
the use of the mould, when it has been filled with clay and the clay is ready to
leave the mould, the case is first removed and afterwards the slips are lifted one at
a time from the face of the block. Now these plaster mould cases are massive and
cumbersome whilst in use, and they are comparatively costly; much plaster of
Paris is used in making them and when they are done with the material is quite
useless. According to our invention we make the mould cases of a fibrous asphalte
and this material we use again and again. The fibrous asphalte is rendered
plastic or semi fluid by heat and in this state is poured upon the slips whilst these
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page_text: are properly arranged around the model. An iron band may be applied around the
case to add to its strength; the band becomes partially or wholly embedded in the
plastic material. As the case cools, it hardens, and the slips can then be removed
in the same way as from a plaster case. When the mould is no longer required the
case is broken up and the material melted and re-used.
The annexed drawings illustrate our invention.
Figure 1 is a perspective view of a model block which it is desired to reproduce
in terra cotta; but it will be understood that these blocks are made in a great
variety of forms and that the model here shewn is selected simply as an example.
Figure 2 is a transverse section showing the model, the plaster of Paris mould
strips, and the mould case.
Figure 3 is a perspective view of the mould and mould case set up for use and
ready to receive the clay to form the moulded terra cotta block.
a a are the plaster mould strips, they are produced in the usual manner and
in Figure 2 they are seen arranged around the model. bb are strips of stiff clay on
which to form the mould case and lessen the depth so that it may not be needlessly
heavy. c is the mould case which is made in the following way.
Fibrous asphalte
in a plastic condition is laid on over the moulded strips when they are in the
position shown in Figure 2; and the asphalte is worked with a trowel and with
the hands until it is brought to the form desired. To give strength to the mould
case a hoop iron band d is worked around it, or in place of hoop iron, wire or wire
gauze may be employed or strengthening bands of other material may be bedded
in or around the mould case when the asphalte is in the plastic state. The mould
case as it cools soon hardens.
The fibrous asphalte we make preferably of the following materials :-
Pitch
-
One hundredweight.
Old plaster moulds ground to powder 56 to 75 pounds.
Cocoa fibre
-
4 to 8 pounds.
-
These ingredients are thoroughly mixed by the aid of heat. This asphaltic
mixture is easily worked when hot and on cooling becomes hard and tough; it can
also be used again and again; it is therefore very suitable for the purpose;
nevertheless other asphaltic materials may be employed.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
Moulds for moulding terra cotta blocks and like articles and consisting of
plaster of Paris mould strips held in a mould case of asphaltic material substantially
as described.
Pitch
One hundredweight.
Old plaster moulds ground to powder 56 to 75 pounds.
Cocoa fibre
4 to 8 pounds.
-
These ingredients are thoroughly mixed by the aid of heat. This asphaltic
mixture is easily worked when hot and on cooling becomes hard and tough; it can
also be used again and again; it is therefore very suitable for the purpose;
nevertheless other asphaltic materials may be employed.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
Moulds for moulding terra cotta blocks and like articles and consisting of
plaster of Paris mould strips held in a mould case of asphaltic material substantially
as described.
Dated this 13th day of July 1801
H. L. DOULTON.
JAMES MILLER CARR.