Note: Descriptions are shown in the official language in which they were submitted.
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SUMMARY OF T~E INVENTION
This invention relates to a mcld unit, and to installations
including a line of mold units, for casting ceramic material
in slip form and particularly, although not exclusively, for
casting articles of sanitary ware of vitreous china.
According to a first aspect of the present invention there
is provided a mold unit for casting ceramic material in slip
form, comprising a plurality of mold parts which are adapted
to be assembled for a casting operation to define between them
two casting cavities arranged, in the casting position of the
mold unit, one above the other, into which slip can be introduced
and which correspond respectively to the shapes of discrete
articles, one of the mold parts having a core for shaping the
article to be cast in the lower cavity of the mold unit and
in its upper surface a separate cavity portion forming, with a
top part of the mold unit, the upper cavity of the mold unit.
Such an installation is particularly suitable for casting
two articles which are intended to be assembled during manu-
facture or which are to be used together, for example a
separately cast flushing rim and a closet bowl or a cistern tank
and a tank cover.
In one form of the invention, the mold unit is arranged
on a support structure and comprises two side mold parts which
are separable by relative movement in a generally horizontal
direction, the core part which with the two side parts defines
the lower of the casting cavities and which is removable from
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the side mold parts in a substa~ltially vertical direetion for
removing an article e~ ~cast in that cavity, and the top pa~t
which rests on the top of the core part and which defines,- with
the cavity portion in the upper surface of the core part, the
upper casting cavity. In such a mold unit, the casting cavity
formed between the t~o side parts and the core part may be
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shaped for solid casting o a cistern tank, and the casting
cavity formed between the core part and the top part may be
shaped to form a cover or lid for the cistern tank;
alternatively, the casting cavity formed between the two side
parts and the core part may be shaped for solid casting a
rimless water closet bowl, and the casting cavity formed between
the core part and the top part may be shaped for casting a
flushing rim, for example, a box rim for assembly with the
closet bowl to make the complete water closet.
In the case where the side mold parts and the core are
shaped for solid casting of a cistern tank, the two side mold
parts are conveniently designed so that one side part has a
substantially vert;ical cavity surface for forming the bacX wall
of the tank and an integral base for forming the bottom wall
~, of the tank, and the other side part is substantially channel- ¦
shaped in plan having substantially vertical cavity surfaces
for forming the side walls and the front wall of the tank.
In the case where the side mold parts and the core are
2i shaped for solid casting a closet bowl, the two side mold
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parts are substantially symmetrical relative to a vertical
parting plane and are each shaped to form half the closet bowl.
An advantage of such mold units is that they are suitable
for mass production in that a plurality of the mold units may
5 be arranged in a generally horizontal line or bank on a support -
structure with one side mold part of one mold unit connected
to the other side mold part of the next adjacent mold unit in
the line, the side mold parts being separated or brought together
by relative movement in a horizontal direction longitudinally
of the line of mold units. These side mold parts do not have
to be lifted bodily at any stage but are simply slid or moved
on roller carriers, for example, in the horizontal direction
for opening and closing. The only lifting required is of the
top mold parts and of the core parts for which there are known
lifting devices available; for example, there may be a single
lifting device mounted so as to be capable of traversing
the whole line, the lifting device being designed to lift
each top mold part and the core mold part, thereby mechanising
a hitherto manual operation with a single device.
There is also disclosed a structure in which the mold
unit is a simple three part assembly for solid casting of
cistern tanks and covers for the tanks comprising a lower part
having a female cavity portion shaped for forming the exterior
surfaces of the bottom, side, front and back walls of the
tank, a core part having a core which fits into the lower part
and having an upper flange part which rests on the upper rim
of the lower part, and a top part which rests on top of the
core part and which defines, with the cavity portion in the
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upper surface of the core part, the upper casting cavity
for casting a tank cover.
According to a second aspect the invention provides a
mold unit for casting two articles which are intended to be
fitted together to form a composite article. In accordance
with this aspect of the invention the mold unit comprises at
least two parts adapted to be assembled to define between
them two casting cavities into which slip can be introduced
and which correspond respectively to the shapes of the two
discrete articles which, after casting, are capable of inter-
fitting to form a composite article, for example a cistern
tank and a lid therefor, or a water closet bowl and a flushing
rim therefor. The mold unit may have at least three parts and
the two casting cavities arranged between them are preferably
arranged, in the casting position of the mold, one above the
other, one of the parts having a first cavity portion which
forms a boundary of the lower cavity and a second cavity portion
disposed in an upwardly facing surface, which forms, with another
part of the mold unit, the upper cavity. -
The casting method using the mold unit in accordance with
the second aspect of the invention comprises the steps of
casting two discrete articles which are capable of interfitting
to form a composite article in a mold unit having at least two
parts which for casting are assembled to define between them
two casting cavities and which correspond respectively to
the shapes of the two discrete articles, the casting step
comprising filling the mold cavities with slip and allowing a
casting time to elapse; the method further comprising opening
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the respective mold cavities, removing the green cast
articles and assembling the two articles while in the green
condition into an interfitting relationship.
BRIEF DESCRIPTION OF T~E DRAWINGS
The invention may be carried into practice in many ways
but certain specific embodiments will now be described, by way
of example only, with reference to the accompanying drawings,
in which:
Fig. 1 is a perspective view of a part of a line of
mold units for casting cistern tanks and tank covers;
Fig. 2 is a side view of the line of Fig. l;
Fig. 3 is a further perspective view of the line of
mold units of Figs. 1 and 2 during emptying;
Fig. 4 is a side view o a mold unit for casting a
closet bowl and a flushing rim therefor; and
Fig. 5 is a view of a three-part mold unit for solid
casting a cistern tank and a cover for t:he tank.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figs. 1 to 3 show an em~odiment for cas~ing of cistern
tanks and covers therefor in a line or bank of fifty or more
mold units arranged in a horizontal line on a support structure
in the form of two rails 7 extending longitudinally of the line.
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Each mold uni-t 1 consists of four main mold parts:- two -
side parts 2 and 3, a core part 4 and a top par~ 5. The side
parts 2 and 3 are supported on carriers 8 fi~ted with rollers 9
so that they can be moved easily on the rails 7 in a longi-
tudinal direction of the line. The side parts 2 each comprise
an upstanding part 11 having a surface 12 which shapes the
external sur~ace of the back wall of the tank c~nd a base part 13
which forms the bottom of the tan~. The side parts 3 each
comprise upstanding mold walls 15, 16 and 17 which form a
channel shape as viewed in plan, the inside faces o which form
the external surfaces of the side and front walls of the tank~
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`, Each pair of side parts 2 and 3 of the same mold ~T~ 1
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can be brought together to define the casting cavity, the
lower side edges 18 and 19 being inclined to the horizontal
to allow the parts to be separated directly by movement i.n a
horizontal direction without khe mold parts scraping against
each other.
In the line of mold units, each side part 2 is connected
rigidl~ in back-to-back relation with the side part 3 o~ the
next adjacent mold unit in the lineO
The core part 4 for each mold unit comprises a core 20
depending from a rim 21 which when the mold unit is assembled
rests on the upper edges of the side parts 2 and 3 ~hich
lie in a common plane. The core part 4 is adapted to be
lifted vertically above the line during emptying or lowering
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so -that the core 20 is located ~etween the side parts 2 and 3
in -the assembled condition o_ each mold uniL.
The upper surface of each core part 4 has in it a cavity
portion 25, female or male, of a discrete casting cavity for
sh~ping the tanX cover, t:he corresponding other portion 26,
male or female, being provided in the underside of the top
part 5 of each mold unit.
In operation, the mold units 1 of the entire line are
assembled by closing up the side parts 2 and 3 and lowering
the core parts 4 and the top parts 5. The line of mold units 1
is then clamped longitudinally by an overall clamping arrange-
ment at each end of the line, not shown. The core parts 4 and
top parts 5 may be held by clamping or other hold-down means,
which may be common to all the mold units, or the core parts 4
lS and the top parts S may be sufficiently heavy simply to rest.
on the side parts 2 and 3 ~;ithout risk of the core mo~ing when
the mold unit is filled with slip under pressure.
The mold units 1 are then filled with slip, the slip
flowing from a slip supply tank unaer yravity into both
casting cavities in each mold unit 1; the inlets for the
. casting cavities may be discrete apertures in the mold wall or
the cavities may communicate with each other by a suitable
duct within the mold unit itself.
After a suitable casting time has elapsed, during which
time moisture is absorbed by the plaster of the molds, the
molds are op~ned. The procedure is first to remove all
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the top parts 5 to e~pose the gxeen cast tan9.~ covers The
core parts 4 with the cover still in situ are then lifted b~
a suitable lifting means whic'n is capable of traversing alon~
the whole line of mold units.
The overall clampins of the side parts is then released
and, dealing with each mold unit in turn, the side parts are
separated by moving side part 3 away from side part 2 on which
the tank rests on the base part 13. The tanl~ 26, shown in
Fig. 3, is then removed using suitable tongs or similar tools
and placed on a rack at one side. The emptied side part 2
is then pulled along the track which movement simultaneously
pulls the side part 3 of the next mold unit to open that mold
unit.
` After removing all the tanks 25, the core parts 4 are
lowered and the tank covers which ha~e remained on top of the
core parts 4 and which have started to dry are removea in
turn and i~ possible are each placed directly on each corres-
ponding cistern tank 26.
It will be appreciated that the particular design of the
` side parts 2 and ~3 enables the cistern tanks to be cast in a
i line or bank casting installation and there are clear
advantages in this.
Fig. 4 shows diagrammatically another example of
casting two articles in the same mold unit, a core-cast rimless
closet bowl cast between side mold parts 30 and 31 and a core
piece 32, and a separate flushing rim, for example a ~ox rim,
cast in a discrete casting cavity 33 formed between the upper
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face of the core piece 32 and a top part 35. As with the
mold units in Figs. 1 to 3, the parts are adapted to be
assembled or opened by horizontal relative movement of the
side parts 30 and 31, and vertical movement of the top part
35 relative to the core piece 32 and of the core piece 32
itself relative to the side parts 30 and 31.
The only difference in this example is that once the
closet bowl and rim have been cast, they are joined together
while still in the green condition to form a complete
closet bowl with an inteyral flushing r;m.
Fig. 5 shows an example of casting a cistern tank and
its cover in the same mold unit made up of three parts adapted
to be separated in a vertical direction. The lower part 40
has the lower casting cavity portion 41 for shaping the
external surfaces of the cistern tank. The intermediate mold
part 45 has an integral core piece 46 adapted to fit within
the cavity portion 41, and, in its upwardly facing surface,
a discrete cavity portion 48 for shaping the lower surface of
the tank cover. The top part 50 fits over the upper surface
of the core part 45 and has in its underneath surface a
cavity portion 51 which shapes the upper surface of the tank
cover and which with the upper surface of the core part 45
defines the entire cover casting cavity.
For casting, the intermediate core part 45 is lowered
onto the lower part 40 with a downwardly presented rim 49
of the core part 45 resting on the upper rim 43 of the lower
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~art, so that the tanl; casting cavity is for~ed, and the top
part 50 is then placed on the upper surface of the core part 45
The assem~ly ma~ then require clamping, or the weight o~ the
parts themselves may make clamping unne_essary.
In operation, the casting cavities are filled either
a~ separate inlets or by a single inlet and an internal
communicating duct, from a common slip supply, a casting time
is allowed and then the top mold part 50 and the core part 4~
are lifted vertically above the lower part by suitable lifting
apparatus. The cistern tank is then removed from the cavity
portion 41 using a pair o tongs or the like by drawing the
tank carefully out in an upward direction clear of the lower
mold part 40, and the tank is placed on a rack at one side.
'Tne upper rlm of the tank is the;n dusted witn a releasing
or non-stick agent. The core part 45 and top part 50 with
the tank cover therein are then lowered into the empty lower
part 40, the top part 50 lifted off and then the tank cover
is removed from the top of the core part, using a han~-held
suction lifting device, and placed carefully onto the tank.
The tank and its cover then proceed to the various finishing
operaCions.
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