IMPROVEMENTS IN MOULDING. ARTICLES OF EARTHENWARE OR PORCELAIN, AND IN APPARATUS USED THEREIN
Year: 1860

page_text: LETTERS PATENT to Robert Jobson, of Dudley, in the County of*
Worcester, Engineer, for the Invention of "IMPROVEMENTS IN MOULDING.
ARTICLES OF EARTHENWARE OR PORCELAIN, AND IN APPARATUS USED THEREIN."
Sealed the 30th April 1861, and dated the 22nd November 1860.
PROVISIONAL SPECIFICATION left by the said Robert Jobson at the
Office of the Commissioners of Patents, with his Petition, on the
22nd November 1860.
I, ROBERT JOBSON, of Dudley, in the County of Worcester, Engineer,.
do hereby declare the nature of the Invention for "IMPROVEMENTS IN MOULDING
ARTICLES OF EARTHENWARE OR PORCELAIN, AND IN APPARATUS. USED. THEREIN,"
to be as follows:-
This Invention has for its object improvements in moulding articles of earthen-
ware or porcelain. When hollow articles of earthenware or porcelain are
Emoulded from dry or partially dry clay by means of a die or mould and plunger
(difficulty is in many cases experienced in consequence of the plunger in rising
carrying some of the clay up with.it, and so destroying or injuring the article.
Now according to my Invention in making a plunger for manufacturing hollow
articles, in place of making the plunger in one piece of metal as has been
usual heretofore, I make the plunger of two parts; the interior or body of the

page_text: plunger is made smaller in diameter than the article to be moulded, and it is
made up to the full size by a ring of metal fitted on to it. The body of the
plunger is made conical, and the ring which fits over it is split at one side, so
that it is expanded when it is forced on; and in order that no space may be
left between the two ends of the split ring a feather is formed on the body of
the plunger to close accurately this space. When an article is to be made
with a compound plunger such as above described, the two parts are placed
together, and the plunger is employed.in all respects as the ordinary plunger
is used; but when the plunger is to be withdrawn from the mould the ring
by a suitable contrivance is held down while the body is partly withdrawn; the
ring then immediately springs in and clears the article, and is then easily
withdrawn without injury. In place of employing a spring ring, as above
described, the ring may be made in several parts arranged around a body, and
when this is withdrawn or partially withdrawn, the parts being capable of
moving inwards "deliver" as already described. When as in the manufacture
of telegraphic insulators it is required to produce two cups, one within the
other, the inner cup springing from the bottom of the outer, then the portion
of the plunger which produces the exterior of the inner cup is similarly retained
in the mould while the body of the plunger is withdrawn, and this part then
springs or moves outwards, so as to clear the article as already described.
the manufacture of some classes of telegraphic insulators and other hollow
articles the plunger or inner die is made in parts, which are sometimes con-
centric with each other, and sometimes in other cases they are not, and they
are capable of sliding on or in each other, so that they may be driven or
pressed into the mould in succession up to a certain extent, and then
driven simultaneously, so as to finish the interior of the article, and by
such construction of the plunger or inner die the article of clay. thus made in
a mould may be held down in such mould by one or more parts of the plunger
"or inner die, whilst another part or parts of the inner die or plunger is or are
removed away; and in place of the plunger or inner die- being fixed to and
-forming part of the instrument which connects.it with the fly. press, I make
such instruments separate from. the plunger or inner die, so that the plunger
or inner die may receive a succession of blows without being raised: out"
of the mould. The concentric parts of such inner die or plunger are in some
cases each composed of two or more. pieces...
In

page_text: "
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Jobson in the Great Seal Patent Office on the
22nd May. 1861.
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 Twenty-second day of November, in the year of our
Lord. One thousand eight hundred and sixty, in the twenty-fourth 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 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
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
This Invention has for its object improvements in moulding articles of earthen-
ware or porcelain. When hollow articles of earthenware or porcelain are
moulded from dry or partially dry clay by means of a die or mould and plunger
difficulty is in many cases experienced in consequence of the plunger in rising
carrying some of the clay up with it, and so destroying or injuring the article.
Now according to my Invention, in making a plunger for manufacturing hollow
articles, in place of making the plunger in one piece of metal, as has been
usual heretofore, I make the plunger of two parts; the interior or body of the
plunger is made smaller in diameter than the article to be moulded, and it is
made up to the full size by a ring of metal fitted on to it. The body of the

page_text: plunger is made conical, and the, ring which fits over it is split at one side, so
that it is expanded when it is forced on; and in order that no space may be
left between the two ends of the split ring a feather is formed on the body of
the plunger to close accurately this space. When an article is to be made
with a compound plunger such as above described the two parts are placed 5
together, and the plunger is employed in all respects as the ordinary plunger
is used; but when the plunger is to be withdrawn from the mould the ring.
by a suitable contrivance is held down while the body is partly withdrawn ; the
ring then immediately springs in and clears: 'the article, and is then easily
withdrawn without injury. In place of employing a spring ring, as above 10
described, the ring may be made in several parts, arranged around a body,' and.
when this is withdrawn or partially withdrawn, the parts being capable of.
moving inwards; "deliver" as already described. When, as in the. manu-
facture of telegraphic insulators, it is required to produce two cups, one within
the other, the inner cup springing from the bottom of the outer, then the 1
portion of the plunger-which produces the exterior of the inner cup is similarly.
retained in the mould while the body of the plunger is withdrawn, and this part
then springs or moves outwards so as to clear the article as already described.
In the manufacture of some classes of telegraphic insulators and other hollow:
articles, the plunger or inner die is made in parts, which are sometimes con- 20
centric with each other, and sometimes in other cases they are not, and they;
are capable of sliding: on or in each other, so that they may be driven' or
pressed into the mould in succession up to a certain extent and then driven
simultaneously so as to finish the interior of the article; and by such con
struction of the plunger or inner die the article of clay thus made in a mould 25
may be held down in such mould by one or more parts of the plunger or inner
die,' whilst another part or parts of the inner die or plunger is or are removed:
away. And in place of the plunger or inner die being fixed to and forming
part of the instrument which connects it with the fly press, I make such
instrument-separate from the plunger or inner die, so that the plunger or 30
inner die may receive a succession of blows without being raised out of the
mould.. The concentric parts of such inner die or plunger are in some cases*
each composed of two or more pieces...
Having thus stated the nature of my said Invention I will proceed more
fully to describe the manner of performing the same.
DESCRIPTION OF THE DRAWINGS.
1:3
Figure 1 shews a vertical section of parts of apparatus for forming -hollow
articles according to my Invention; the article shewn in the Drawing is part
35

page_text: of an electric telegraph insulator, but other hollow articles may be similarly,
formed, the compound plungers and moulds being modified according to the
internal and external form of each particular article, which modifications will
readily be made by a workman when aided by the description herein given.
A and A are, the two parts of which a plunger is composed, and B is the
outer mould or die within which the hollow article C is produced. The central
part A of the plunger is in one piece, and is fixed to the screw or other press
employed. The part A*, which is concentric with the central part A, is, by,
preference, of three parts, which butt together to form a concentric ring
around the central part A of the plunger. It is not necessary that the parts
A of the plunger should be connected together, and it is preferred, in some
cases, that they should be separate one from the other. The mould B.for
making the article shown. it is preferred should: be in three parts hinged
together. The number of..the parts of the plunger,.and also of. thé. mould.
may be varied, depending on the nature and form of the article. The mould.
is introduced into an exterior mould or holding die D, the interior of which
fits the exterior of the mould; F is the bottom to the mould.B and holding
die D, by which the mould B. and. moulded article C are raised out of: the
outer. holding die D. In this arrangement the part A of the plunger would
be first lifted 'out, then the moulded article, and the mould B would be lifted
from D, and when the parts of the mould B have been removed the concentric
parts A of the plunger would next be removed from the moulded article. In
some cases it is desirable that the exterior ring of the plunger should be
capable of being expanded. Figure. 2. shows part of a vertical- section, and
Figure 3 a horizontal "section of a plunger, suitable for causing the outer-ring
to be expanded before. the plunger is forced or driven into a similar mould, to
that above described, varied only to suit the difference of the form of the
present insulator C. In the arrangement shown at Figures 2 and 3 the outer
ring A* is in three parts hinged together and drawn towards each other by an
india-rubber spring which passes through an opening in the inner-part A. On
the surface of the inner part A of the plunger there is a feather a which comes
between the parts of the outer ring A* and causes the parts thereof to be
expanded, and in this state the plunger is used as if it were of one part only ;
G is another outer ring, which is carried by six pins which pass through a
ring or projection on the outer surface of the inner part A of the plunger
The upper ends of the pins are fixed to another ring G*, by which arrange-
ment the inner part A of the plunger may be first raised, leaving the outer
ring G on the edge of the article, and as the feather is withdrawn the sides of
the outer ring.A will become free and at liberty to spring towards each

page_text: other, the ring G remaining in position till the inner part A of the plunger is
raised out of the article C a sufficient distance for the ring or projection on
the part A to lift the ring G*, and consequently the ring G..
... In place of the ring A* being in parts it may be formed in one piece;
and elastic, so that the two ends may spring towards each other when the
feather, is withdrawn...
It is found desirable in some cases to produce the desired effect by a suc
cession of impacts on the plungers employed, and that the parts of the plungers
should be arranged to be acted on in succession as well as simultaneously;. for
this purpose the compound. plungers used' are made. separate from the fly or
other press used, so that a succession of blows may be given to the parts of a
plunger without lifting such parts out of the article which is being formed in a
mould; Figure 4. shows a section of a plunger consisting of three parts
A, A*, A**, which are acted on by a succession of impacts by the forcer of a
press; the 'dotted lines show the positions which the parts of the plunger may
assume at starting; Figure 5 shows a vertical section of a compound plunger,
consisting of an internal part surrounded by external concentric rings, suitable
for: making an insulator C of a particular form; but such parts will be varied
when making other forms of insulators or other forms of hollow vessels.: In
this Figure the mould employed will be such as is above described, but it is not
shown in the Drawing; Figure 6 shows a plan of the compound. plunger;
Figure 7 shows a transverse section thereof, the outer ring being shown to.be
of one piece, but this may be varied when the particular form of the article.to
be moulded requires variation in the form and construction of the outer ring
or rings of the plunger; Figure 8. is another vertical section taken at right
angles to the section, Figure 5; A is the interior part of the plunger, the form
of which (for the particular article C) is shown in the Drawing; A* is the
outer part or ring of the plunger; H is another outer concentric part or ring.
of the plunger. This ring H is connected by rods or screw bolts I to the
cross head J, which, by screw bolts, is affixed to the outer ring A* of the
plunger; K is the ram of the fly or other press used, and it will be evident.
from the form of the upper part of the interior of the plunger A, that it may
receive a succession of blows..
The cross head is, on its under side, pressed on by a spring L tending. to
force it upwards within the slit formed at the upper part of the interior portion
A of the plunger. The part A of the plunger is: withdrawn a distance, whilst
the cross head and parts connected therewith are kept pressed down by any
suitable means whilst such lifting of the part A is being performed, then the
whole of the plunger is lifted out of the moulded article. In the Drawings
3

page_text: I have only thought it necessary to show the plungers and moulds suitable for
moulding particular forms of earthenware insulators for electric telegraphs,
but a workman, aided by them and the description herein given, will readily
prepare. plungers and moulds for making other articles, such as tea cups and
others. The clays, or compounds containing clay, used in making articles of
earthenware or porcelain, are introduced into the moulds used in a dry or
partially dry state, in the form of powder, or if preferred, the articles may be
first roughly formed or moulded of suitable plastic clay or compounds, and
when in a dry or nearly dry state, the articles may be introduced into the
moulds and acted on by compound plungers according to my Invention..
In witness whereof, I, the said Robert Jobson, have hereunto set my
hand and seal, this Eighteenth day of May, in the year of our Lord
One thousand eight hundred and sixty-one.
ROBERT JOBSON. (L.S.)