IMPROVEMENTS IN MOULDING ARTICLES OF CLAY, EARTHENWARE, OR PORCELAIN, AND IN APPARATUS USED " THEREIN
Year: 1866

page_text: LETTERS PATENT to Robert Jobson, of Dudley, in the County of Wor-
cester, Engineer, for the Invention of "IMPROVEMENTS IN MOULDING
ARTICLES OF CLAY, EARTHENWARE, OR PORCELAIN, AND IN APPARATUS USED
"
THEREIN."
Sealed the 24th July 1866, and dated the 3rd February 1866.
PROVISIONAL SPECIFICATION left by the said Robert Jobson at the
Office of the Commissioners of Patents, with his Petition, on, the
3rd February 1866.
I, ROBERT JOBSON, of Dudley, in the County of Worcester, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
MOULDING ARTICLES OF CLAY, EARTHENWARE, OR PORCELAIN, AND IN APPARATUS
USED THEREIN," to be as follows:-
In moulding articles from plastic clay it is frequently desirable to submit
the clay whilst in the mould to pressure by means of a plunger forced
down upon it. This cannot be done conveniently in the moulds now
employed, because however carefully the mould may be made the pressure
will, as soon as the mould becomes somewhat worn, drive the clay through
the joints between the several parts of which the mould is necessarily
made in order that it may deliver the article when it has been.
moulded.
Now according to my Invention I place in each of the joints of the
mould (which I usually make of metal) a strip of a soft or compressible

page_text: material, such as leather, wood, or felt, for example, and thus the joint
is made tight. The use of soft or compressible strips in the joints, as
above described, offers great facility for moulding articles in plastic clay,
as it allows of the use of compound plungers such as are described in
the Specification of a former Patent granted to me and dated the 22nd
November 1860, No. 2862. I also according to my Invention form small
grooves in the plunger by which the pressure is applied, so that any
surplus clay which may be put into the mould may pass out through the
grooves and escape from the mould, and by turning the plunger the strips
so formed are at once detached from the moulded article.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Jobson in the Great Seal Patent Office on
the 2nd August 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
JOBSON, of Dudley, in the County of Worcester, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of February, in the year of our Lord
One thousand eight hundred and sixty-six, in the twenty-ninth year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Robert Jobson, Her special licence that I, the said
Robert Jobson, my executors, administrators, and assigns, or such others
as I, the said Robert Jobson, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN MOULDING ARTICLES OF CLAY, EARTHENWARE, OR PORCELAIN,
AND IN APPARATUS USED THEREIN," upon the condition (amongst others)
that I, the said Robert Jobson, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months' next
and immediately after the date of the said Letters Patent.
NOW KNOW YE that I, the said Robert Jobson, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-

page_text: formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
In moulding articles from plastic clay it is frequently desirable to submit
the clay whilst in the mould to pressure by means of a plunger forced down
upon it. This cannot be done conveniently in the moulds now employed,
because however carefully the mould may be made the pressure will, as
soon as the mould becomes somewhat worn, drive the clay through the joints
between the several parts of which the mould is necessarily made in order
that it may deliver the article when it has been moulded. Now according
to my Invention I place in each of the joints of the mould (which I
usually make of metal) a strip of a soft or compressible material, such as
leather, wood, or felt, for example, and thus the joint is made tight. The
use of soft or compressible strips in the joints as above described offers
great facility for moulding articles in plastic clay, as it allows of the use of
compound plungers such as are described in the Specification of a former
Patent granted to me and dated the 22nd November 1860 (No. 2862).
I also according to my Invention form small grooves in the plunger by
which the pressure is applied, so that any surplus clay which may be put
into the mould may pass out through the grooves and escape from the
mould, and by turning the plunger the strips so formed are at once
detached from the moulded article.
Having thus stated the nature of my said Invention, I will proceed
more fully to describe the manner in which I perform the same.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows a vertical section, and Figure 2, a plan of a mould and
plunger such as I employ when moulding earthenware or china insulators
or caps for electric telegraph wires, which is a good example of the class
of articles to which my Invention is applicable, and a workman will
readily, aided by the Drawing annexed, and the description of the same
and of the process employed in forming such articles, construct and work
other moulds and plungers for the production of other forms of insulators,
as also other articles differing in shape from that shown in the Drawing.
The plunger is made in three parts, of which a is the central part, which
is first withdrawn; a¹ is external of the part a and slides thereon, and a²
is another part which is external of the part a', and it is capable of move-
ment independently of the other parts, so that it may remain down till the
pait a¹ has been drawn back. The central plunger a may be fixed to the
ram or holder 6 of a press; c is the bed or mould, which is cylindrical on

page_text: the interior, and has a moveable bottom c by which the interior lining
and parts, together with the moulded article, may be lifted out of the
lower mould c. In the arrangement shown the lining of the lower mould
is made in three parts, by preference of metal, but they might be of wood
or other suitable material. The object of having the internal lining c³ of
parts hinged together is to admit of the article moulded having grooves or
projections formed therein or thereon. Soft compressible material, leather
by preference, is introduced at c*, c*, between the parts of the lining where
they come together, and similarly at c**, where they butt or come against the
moveable bottom c¹; thus when the parts of the lining come together and
are pressed tightly into the lower mould c the joints are made perfectly
tight, and the clay which is somewhat moist and plastic cannot pass at the
joints; a*, a*, also are rings of compressible material placed between the
parts of the plunger to prevent leakage. Where it is necessary to make
the articles accurately to a given size the plunger is grooved externally
with very small grooves longitudinally, as before stated, to allow the
escape of any superfluous clay. When the lining of a mould is itself made
of wood or soft compressible material which will more or less give way
when shut or pressed together, then separate strips of soft material may
be dispensed with. Where the articles moulded have no grooves or
projections, such as require the lining of the mould to be made in
parts, such lining may be of one piece, using, however, strips of soft
materials where the butting parts would otherwise allow of the clay being
driven through by the great pressure to which the clay is subjected when
being moulded.
In witness whereof, I, the said Robert Jobson, have hereunto set my
hand and seal, this Twenty-eighth day of July, in the year of our
Lord One thousand eight hundred and sixty-six.
ROB. JOBSON. (L.S.)