Note: Descriptions are shown in the official language in which they were submitted.
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Mould for production of building elements
This invention relates to a mould of elastically deform-
able material for production of cast building elements, prefer-
ably from concrete, one or more surfaces of which elements are to
be provided with a plastic layer of a somewhat flexible material,
such as plastic.
From Swedish PS 219 154 it is known to produce castings
of for example concrete, plaster or plastics by introducing the
casting material into a mould the inner surface of which is
covered by a diaphragm of a flexible material, the diaphragm
being held in contact with the inner walls of the mould by
vacuum. When the casting is set it may be removed from the
mould by replacing the vacuum by a suitable pressurizing.
From Norwegian PS 127 228 it is known to produce one
sided open mould pieces of fibre cement using a dish shaped
supporting body, which supporting body may be secured by electro-
magnets or by a vacuum. Further, from publicly available
Norwegian Patent Application 197/68 a method and an apparatus
for the production of decorated injection moulded plastic articles
are known, a decorative foil being held by vacuum in the female
part of the mould, followed by introducing in the mould of a
casting material adhering to the foil so that after setting the
foil forms an integral part of the moulded article.
From British PS 1 082 254 a method is known for pro-
ducing articles of cement conglomerates and a mould to be used
therefore. This mould is made from flexible or resilient
material and has a rigid outer supporting frame. After the
mass having hardened the supporting frame is removed and then
the inner elastic mould is pulled off the moulded article which
is provided with projecting portions.
As already mentioned the invention relates to a mould
for production of bui ~ g elements having at oné or more sides a
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layer of a somewhat flexible material, such as plastic, which
elements for instance may be staircase steps which at one or
more
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sides are to be provided with a layer of plastic. The moulding
of such buildinq elements is a complicated procedure since the
end product may he provided with sharp edqes, projecting
- portions, recesses and different details, and a displacement
of the layer during production may render the product unusable.
When vibratinq the mass the layer may easily be displaced so
that the product cannot be used. Furthermore, leakage of
concrete water will represent a disadvantage.
According to the present invention there is provided
a mould for the production of cast buildinq elements from water-
containing casting material upon at least a porti/on of the outer
surface of which there is integrally cast a~cover layer of a
different material, comprising a mould made of elastically
deformable material and having a recessed interior portion, a
rigid plate-like member positioned within said mould recess
having a surface corresponding to the external surface of at
least a portion of said cover layer, said mould having pro-
jection means in contact with said cover layer for preventing
the escape of water from the mould upon vibration of the latter,
means cooperating with said rigid plate-like member for main-
taining the portion of said cover layer overlaying said rigid
plate-like member in close engagement therewith during the
moulding process.
In accordance with the present invention portions of
the moulding recess of the mould, substantially corresponding
with the surface of the plate shaped layer, are formed by a
rigid plate which is arranged in the mould and against which a
" corresponding surface of the plate shaped layer may be kept in
a predictable stable position during the moulding process.
The layer or cover may be secured to the rigid plate by vacuum,
-, magnets, double sided adhesive tape or by temporarily supporting
bolts. The preferred method for keeping the cover in place in
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1088
the form is by means of vacuum.
The present invention will be further described by
reference to the accompanying drawing in which:
Fig. 1 is a vertical section of a mould, in which
vacuum is used for keeping a layer of plastic material and a
front ledge or "step nose" of plastic material in place during
the moulding process,
Fig. 2 is a part of another embodiment in which the
layer and the nose are kept in position by means of magnets
co-operating with reinforcing irons, and
Fig. 3 shows in perspective a part of a mould with
removable supporting bolts which keep the cover and the nose
in position during the first part of the moulding process.
In Fig. 1, an inner mould 1 of elastically deformable
material, such as polyurethane, is elastic to such degree that
it may, when the moulded article is to be removed
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from the mould, be stretched beyond the protruding portions of
the ready moulded product without the mould being damaged. A
rigid outer supporting mould 2 serves to secure the stability
of the soft inner mould 1. A rigid, loose plate 3, for instance
of steel, forms the substantial part of the bottom of the mould
and defines at its inner side a vacuum chamber 4, said plate 3
being gas tightly arranged within a recess of the inner mould,
which recess is defined by projecting portions a and b of the
mould. In said plate 3 there are arranged along one or more
edges through-holes 3', so that the plastic cover will be sucked
to the plate when vacuum is applied to the vacuum chamber 4.
~ SAid plate 3 also serves as a flat support for the flexible
cover or covers 6 and/or 7 which are to be moulded fast to the
article 8. In order to prevent the plate 3 from being bent under
the influence of vacuum in chamber 4, there may be arranged dis-
tance pieces in said chamber, for instance made from rigid poly-
ethylene. The vacuum chamber 4 is connected with a tube 5 which
may be connected with a suitable suction pump, not shown.
The covers 6 and 7 to be moulded fast furing the pro-
duction are kept in position by being sucked to the plate 3 whichis placed in a recess in the bottom of the mould 1. By means of
the projecting portions a and b of the mould, concrete water is
prevented from escaping from the mould.
Fig. 1 also shows a front edge ledge or "nose" 7 which
is also made from elastic material, such as extruded polyvinyl-
chloride. Said ledge is welded or glued to the cover 6 and is
kept in water tight manner against the side wall c of the inner
mould 1 so that concrete water is also prevented from escaping
at this place. The article 8 is in the present case made from
concrete which may in case also be provided with reinforcing
irons.
The mould according to the invention is used in the
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following way:
The inner mould 1 with distance elements in the vacuum
chamber and with the suction tube 5 is arranged in the rigid
outer mould 2, whereupon plate 3 is arranged on the bottom of
the mould. Thereupon the cover 6, possibly with the front edge
ledge 7 welded or glued thereto, is placed in the form, and
`vacuum is applied to the vacuum chamber 4, so that the cover is
sucked fast to the plate 3. Then the mould is filled with con-
crete and in case also reinforcing iron, whereupon the concrete,
if necessary, is~ vibrated so that the mould is completely filled
with concrete. After termination of the vibration the vacuum
in the chamber 4 is released and the mould placed aside for
hardening. After sufficient hardening the outer mould 2 is
removed, whereupon the elastically deformable inner mould 1 is
turned off the moulded article 8, so that the product is freed
from the mould.
By using different inner moulds and corresponding outer
moulds different building elements may be produced on one or
more of the outer surfaces of which there are moulded fast covers
which will be kept in correct position during the moulding pro-
cess by means of suction.
Fig. 2 shows an alternative in which the retaining of
the covers 6, 7 by means of vacuum has been replaced by magnets
10 which co-operate with reinforcing iron 9 arranged on the
bottom of the mould 1 prior to the introduction of the mass.
The same effect may be obtained by instead of using
vacuum according to Fig. 1 or electromagnets according to Fig.
2 to use a both-sided adhesive tape, one side of which adheres
to the upper side of the plate 3 and the other side adheres to
the cover 6, 7.
A fourth possibility appears from Fig. 3, in which the
inner mould 1, the outer mould 2 and the plate 3 are the samc as
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already described. The cover 6 and/or the covers 6 and 7 are
arranged in the bottom of the mould, whereupon on this cover or
covers there is placed a frame 11 provided with a plurality of
conically reduced bolts 12 which are longer than the thickness
of the ready article and which will keep the covers 6 and/or 7
in position during introduction ofthe mass. After atleast one
half of the mass has been introduced, the frame 11 with bolts 12
may be removed, whereupon the rest of the mass is introduced and
the mould is preferably vibrated in order to obtain that the
recesses formed by the bolts 13 are completely filled with con-
crete.
