Improvements relating to the Manufacture of Pottery from Plaster Moulds and applied Mechanism.
Year: 1898

page_text: Date of Application, 20th Aug., 1898
Complete Specification Left, 23rd May, 1899-Accepted, 22nd July, 1899
Improvements relating to the Manufacture of Pottery from Plaster
Moulds and applied Mechanism.
FREDERICK HANCOCK, 121, Victoria Road, Stoke-on-Trent, Earthenware Manu-
facturer, do hereby declare the nature of this invention to be as follows:-
:--
This invention has for its object, the production of teapots and like vessels, with
a fixed verge for reception of cover; in earthenware, jet and Rockingham wares,
and other species of pottery; from the jigger with the aid of a jolly and suitably
constructed plaster or metal moulds.
Hitherto, only the cheaper grades of goods produced from the jigger, such as
Rockingham and inferior jet wares, are admissible for firing after leaving
this stage of production; in this case, a second application is necessary to excavate
the verge of vessels for the reception of cover. The superior teapots in these
classes in addition to all others, are invariably shaved on the lathe, the verge
being countersunk by the turner.
My invention is devised to obviate this latter necessity, and to produce a
finished moulded vessel with one-joint application. To accomplish this, the
complete mould is made up of two parts, namely, a top and bottom section; the
circular line of demarcation being arranged to suit the configuration of the vessel,
and is always located at that part where the diameter is greatest; suitable pro-
vision being made in the side of the mould for the scrap clay pinched off at
junction of parts. To insure the vertical position of the combined mould when
horizontal pressure is applied by the arm of jolly, a metal cylinder of suitable
capacity is employed to surround the complete mould; the diameter being such
that it just passes over and lodges round the latter, the length being so adjusted
that each half of the cylinder remains on either side of the junction of parts.
Under these conditions, a metal profile corresponding to the inside configuration
of the whole of a finished vessel, and amenable to spring and rotary motions,
when applied, will effect the desired result. The iron ring may be removed after
withdrawal of the latter, and the mould will deliver a complete vessel, which
may be trimmed for service, without being lathed or shaved.
An alternative method may be employed with the aid of jolly, by applying to
top section of vessel, a profile, which corresponds to the complete configuration
thereof, joining same to the lower section after the latter has been impressed to
the mould by hand pressure only; in order to avoid wearing the seam of the
mould, which would be the case, if a metal tool were employed; as the latter
cannot be effective without the addition of moisture; which, during the operation,
would rise to the top of the mould, spreading over and adhering to same, and
would need the constant application of a metal tool to remove; this action, would
early wear down the edge of the bottom mould, with the result that a thick and
unsightly joint or seam would ensue; and this would necessitate shaving or
lathing to remove.-Whereas, to jigger the bottom section by hand, moisture is
not required; and as any surplus clay emerges above the top of the mould, it is

page_text: casily and readily removed by the finger; the top part surrounding the junction,
remaining perfectly clean. The joining of sections is accomplished on the jigger
by placing the top section over the lower, and by slight pressure from the hand
over the junction part of the vessel during the rotary motion of the jigger.
In vessels which have a tubular trunk depending from the mouth, I propose
to produce the latter in conjunction with the collar or neck of pot; the configura-
tion of the outside of section, being determined by the mould, and on the inside by
the profile tool attached. to jolly; it may be delivered from mould in a ready
condition for fixing to the main vessel, and would embrace a tubular channel;
having no holding capacity whatever.
The combination of parts would be effected after partial drying from the out-
side, on a rotary disc; the joint being ornamented by a runner or other milling
tool if desired.
It is necessary that the moulds employed shall be perfectly true, & circular in
their action.
To prevent their irregular production, I propose to adjust the cases, or mother
moulds in circular; unbroken, block sections of an inter-locking character, so
that the inevitable expansion of plaster, which ensues on admixture with water;
shall be perfectly vertical in its deportment. The amount of expansion, is always
in ratio to bulk of plaster employed; and as the configuration of a vessel, decides
the amount of plaster contained in a bottom and top section of a complete mould;
it is obvious that horizontal expansion, must be avoided in their production;
as each section is produced from separate case moulds; and their bulk invariably
differs hence the importance of rigidly holding this force in check; otherwise,
they would not inter-lock with each other when required for use.
I do not bind myself to any particular number of sections in the constitution
of the mother mould, as the latter would be governed by the necessities of any
particular case.
Dated this 19th day of August 1898.
İmprovements relating to the Manufacture of Pottery from Plaster
Moulds and applied Mechanism.
I, FREDERICK HANCOCK, late of 121, Victoria Road, but now of Elgin House,
Stoke-on-Trent, in the County of Stafford, Earthenware Manufacturer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:—
This invention has for its object the production of teapots and like vessels with
a fixed verge or flange for the reception of the cover, in earthenware, jet and
Rockingham wares and other species of pottery, from the jigger with the aid of
a jolly or jollies and suitably constructed plaster or metal moulds.
Hitherto only the cheaper grades of goods produced from the jigger, such as
Rockingham and inferior jet wares, have been admissible for firing after leaving
this stage of production, and a second operation has been necessary to excavate
This second
the clay to form the verge or lip for the reception of the cover.
operation consisted in moulding the mouth of the vessel very thick, and then
shaving off sufficient in the lathe to leave a laterally projecting verge or lip

page_text: below the part shaved off, this shaved off part constituting an embayment for the
reception of the lid which rests on the verge. The consequence was that the
diameter of these embayments varied in each vessel and the lids were not inter-
changeable.
Now my invention is devised among other things to avoid these defects, and to
produce a finished moulded vessel without any turning or shaving in the lathe
being necessary, thus cheapening the manufacture thereof. The manner in
which I accomplish this will be understood from the following description, refer-
ence being had to the accompanying drawings, in which:
Figure 1 is a vertical section of plaster moulds showing the surrounding metal.
cylinder or ring;
Figure 2 the metal profile tool for use with these moulds; Figure 3 a vertical
section of plaster moulds illustrating a slight modification in the process, applied
to a jigger head; Figure 4 a front elevation of the jigger with lever jolly con-
structed in accordance with my invention; Figure 5 a vertical jolly fitted with a
metal profile tool.
The complete mould is made up of two parts A and B namely a top and
bottom section, the lower half of the article being formed by the bottom section
of the mould, and the upper part by the top section thereof. These moulding.
sections A and B are mounted in the usual rotating jigger head D, and the two
sections fit accurately and concentrically together, this being ensured by an
annular projection a on one engaging into an annular groove b on the other.
This ensures the two parts fitting truly concentric, and does away with the
usual plan of providing bosses or snugs on one of the moulds fitting into depres-
sions on the adjacent face of the other mould, which were so liable to be muti-
lated because in putting the two moulds together, they had to be manipulated
until the snugs on one mould dropped into the depressions on the other. By my
arrangement this objection is overcome, as the two moulds can be fitted together
without this manipulation. The central line of demarcation F between the
moulds is arranged to suit the configuration of the vessel and is always located at
that part where the diameter is greatest, an embayment being made in the side
of the mould at G for the scrap clay pinched off at the junction of parts.
Referring first to Figure 1, the moulds are put into rotation by the jigger
head and the clay being roughly formed by hand into the shape of the mould,
a non rotatable metal profile tool, such as I (Figure 2) corresponding with the
inside configuration of the whole of a finished vessel is applied to the inside of
the partly formed article by a jolly of the vertical type, (Figure 5), this tool
forming by one operation the embayment E which receives the lid and the
verge on which the lid rests as well as shaping the inside of the vessel. To
ensure the vertical position or concentricity of the combined mould when hori-
zontal pressure is applied by the jolly, a metal cylinder or ring H of suitable
capacity is employed to surround the complete mould, the diameter being such
that it just passes over and lodges on projection T surrounding the latter, the
length being so adjusted that half of the cylinder remains on either side of the
junction of parts.
An alternative method will be understood by reference to Figure 3 in which
the vessel C is made separately in top and bottom sections and these two sections
then joined together, instead of the vessel being made in one piece. The top
mould A is first mounted in the usual jigger head 1) in an inverted position, the
part a being formed so as to fit into the jigger head. The non-rotatable metal
profile tool corresponding to the inside configuration that is required for the top
portion of the vessel is then applied to the rotating piece of clay in the mould by
a jolly of the vertical type. This tool forms the clay into the shape required for
the top section by one operation including the embayment E which receives the
lid, and the verge D on which the lid rests. The top mould A is then removed
from the jigger head and the bottom mould B inserted. therein, and being set
into rotation, the profile tool K of the lever jolly such as that set forth in Figure 4

page_text: is applied. This forms the clay placed therein into the shape required for the
bottom section.
These two operations are effected in the same jigger head, but by two separate
jollies so fixed on the same bench that their tools can be brought to operate on
the clay in the two sections of the mould placed alternately in the jigger head.
For this purpose they are placed obliquely to each other, on the same bench, so
that the one which is being operated will not interfere with the other which is
not being operated and vice versa. When the two sections of the vessel have been
formed they are joined on the jigger head by placing the top section of the
mould on to the lower section of the mould concentrically before the bottom
section has been removed from the jigger, and by slight pressure from the hand
over the junction part of the vessel during the rotary motion of the jigger. After
drying, the mould will then deliver a complete vessel which may be trimmed for
service without being lathed or shaved.
The lever jolly referred to in the previous paragraphs is set forth in Figure 4.
L is the lever, K the profile tool secured thereto, № a stop to limit the move-
ment of the lever, N a handle by which the lever is operated. The lever is so
mounted on its axis that when the lever is brought down it will apply the
tool to the clay in the bottom mould in the jigger head, and when this operation
is completed the lever will rise by the counterweight P, the tool in its ascent
clearing the moulded article. The vertical jolly which in use is fixed on the
same bench T as the lever one, is set forth in Figure 5. In this Q is a vertical
shaft having a longitudinal movement, and capable also of rotating part of a
turn. J is the metal profile tool secured to the arm of the shaft Q. The
shaft Q is placed in such a position relatively to the jigger that when the shaft is
rotated by the turning of the handle R, this tool will rotate in a circle eccentric
to that of the mould. The result is that when the top part of the vessel has been
moulded by the application of this tool, a turn of the handle will move the tool
clear of the vessel, and the spindle will be raised by the counterweight S.
It is necessary of course that the moulds employed shall be perfectly true and
circular, as otherwise they will not be concentric, and the result will be the pro-
duction of faulty vessels having unsightly joints or seams. To prevent their
irregular production I make the mother moulds in circular, unbroken, block
sections, of an interlocking character, bound round their outside circumferences
with strong metallic bands. The result is that the inevitable expansion of plaster
which ensues on admixture with water is resisted so far as its radial or horizontal
direction is concerned and the expansion is forced to take place wholly vertical.
The bands ensure that the mother moulds are not fractured, or in any way
injured by the expansion of the plaster so that the plaster moulds cast in these
mother moulds are perfectly true and concentric. The amount of expansion of
the cast plaster is always in ratio to the bulk of plaster employed, and as the
configuration of the vessel decides the amount of plaster contained in the bottom
and top section of the complete mould, it is obvious that horizontal or radial
expansion must be avoided in their production. Hence the importance of rigidly
holding this force in check, otherwise the two sections of the mould would not
interlock with each other when required for use. By using these bands therefore,
I obtain mother moukls which will absolutely prevent horizontal or radial expan-
sion of the plaster in casting the jigger moulds, and therefore I am able to fit
the two sections of said moulds together by the annular projecting ribs a
engaging in the annular groove b, which arrangement is much preferable to the
old plan of providing snugs engaging in depressions.
I do not bind myself to any particular number of sections in the constitution
of the mother mould, as the latter will be governed by the necessities of any
particular case.
A vessel produced by my process will have more perfect regularity of production
and the lid being made to fit one vessel, will fit all vessels made by the same tool

page_text: thus making them interchangeable, also exact uniformity is secured in the size
of the lip.
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:-
1. The improvement in the manufacture of teapots and like vessels in earthen-
ware and the like, that are formed in moulds consisting of two sections divided
by a transverse line of demarcation, namely providing in combination with a
rotating jigger, in which the two sections of the moulds are alternately placed, a
pair of jollies so fixed on the same bench that their profile tools can be alter-
nately applied to the clay placed in the respective sections of the moulds, and in
making the profile tool of one of these jollies in such a manner that it will form
by one operation the embayment of the lid, the lip on which the lid rests, and
the entire inside configuration that is required for the top of the vessel, whereby
a finished moulded vessel can be produced without any subsequent turning or
shaving in a lathe being necessary, substantially as described.
2. Making the verge or lips in teapots or like vessels during the actual
operation of moulding the clay in the jigger moulds consisting of two sections
only, by means of a metal profile tool applied by a jolly substantially as described,
whereby a finished mouded vessel is produced without any subsequent turning
or shaving in a lathe being necessary, thus cheapening the manufacture, sub-
stantially as described.
3. The combination with a complete plaster mould consisting of two sections
only, of a metal cylinder or ring adapted to surround the complete mould and
keep the two parts in position substantially as described, whereby the vertical
position or concentricity of the two sections even when horizontal pressure is
applied by the jolly tool, is ensured.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London.
Patent Agents,