[0001] The present invention concerns a production method for fabricating a concrete pillar
or beam, according to which method the concrete mix is sprayed against the wall of
a mold having a predetermined shape, after which the concrete surface is smoothed
by levelling.
[0002] With reference to Finnish patent applications 872244 and 872245, similar production
methods have been previously disclosed. The aim of the present invention is to achieve
advancements in this production method. The method in accordance with the invention
is characterized in that the concrete surface is levelled with the help of a surfacing
disc, whereby the pillar or beam is rotated so as to place one side of the pillar
or beam at a time facing the surfacing disc so that the pillar or beam achieves a
section of a square, rectangle, pentagon, hexagon, or a similar form. Thus, with the
help of the invention, pillar constructions with an appealing look are achieved that
are readily transferrable and transportable by virtue of their hollow-core construction.
Although the concrete pillar has a hollow-core structure, its compressive strength
will be sufficient for a majority of applications. If necessary, the hollow core can
be filled with concrete mix.
[0003] An embodiment of the invention is characterized by having the mold rotatable about
its vertical axis and having a positional clamping facility for spraying and surfacing.
This approach results in a quick production method for a concrete pillar, which is
then transported for curing and hardening after spraying and surfacing.
[0004] Another embodiment of the invention is characterized by having the mold placed in
a horizontal rotator, and the rotator is used for turning the beam during production
to alternately align three of the four sides of the beam facing the concrete spray
gun and the surfacing disc so as to achieve a U-shape cored beam structure. This approach
results in a cored beam structure, which has a predetermined structural strength and
can be, when required, further steel-reinforced and filled with concrete mix at the
construction site.
[0005] A further embodiment of the invention is characterized by having the mold structure
fabricated by winding plastic material, thin steel sheet or like material over elongated
bars positioned so as to achieve a desired shape of the mold. The mold structure is
further provided with, e.g., reinforcement fabric which offers improved adherence
for the sprayed concrete mix prior to the surfacing operation.
[0006] In the following, the invention will be examined in more detail by means of exemplifying
embodiments with reference to the attached drawings, in which
Figs. 1 and 2 show a cross-sectional view of a production method for a pillar with
hexagonal cross-section.
Figs. 3...8 show a production method for a beam structure with U-shaped cross-section.
Fig. 9 shows the removal of a ready-cast beam structure from the rotator.
Figs. 10...12 show cross-sections of different mold structures.
Figs. 13...17 show a production method for a vertically aligned beam.
[0007] According to the production method, concrete mix is sprayed against the walls of
a mold 1, 2, 3, 4, 5 having a predetermined shape, after which the concrete surface
is levelled. The concrete surface is levelled with the help of a surfacing disc 6
so by way of rotating the pillar or beam so as to place one side of the pillar or
beam at a time facing the surfacing disc so that the pillar or beam achieves a desired
cross-section.
[0008] In accordance with the Figs. 1 and 2 as well as Figs. 13...17, the mold is rotatable
about its vertical axis and has a positional clamping facility for spraying and surfacing.
In accordance with Figs. 3...9, the mold 2 is placed in a horizontally aligned rotator
7, and the rotator is used for turning the beam during production to align three of
the four sides of the beam facing the concrete spray gun and the surfacing disc apparatus
so as to achieve a U-shaped cored beam structure. The cored beam and the mold are
removed from the rotator 7 as indicated by arrow 8. Illustrated in Figs. 10 and 13
is a method for forming the mold structure using plastic sheet wound over thin bars
9. Bars 10 and wire 11 form a fabric structure, which provides adherence to the concrete
mix.
[0009] In accordance with Fig. 11, the mold can be formed from metal sheets 4 shaped as
angle profiles.
[0010] In accordance with Fig. 12, the mold is formed of angle steel profiles and elongated
metal sheet strips 3.
1. A production method for fabricating a concrete pillar or beam, in which method
the concrete mix is sprayed against the wall of a mold (1, 2, 3, 4, 5) having a predetermined
shape, after which the concrete surface is smoothed by levelling, characterized in that the concrete surface is levelled with the help of a surfacing disc (6), whereby
the pillar or beam is rotated so as to place one side of the pillar or beam at a time
facing the surfacing disc so that the pillar or beam achieves a section of a square,
rectangle, pentagon, hexagon, or a similar form.
2. A method as claimed in claim 1, characterized in that the mold (1, 5) is rotatable about its vertical axis and has a positional
clamping facility for spraying and surfacing.
3. A method as claimed in claim 1, characterized in that the mold (2) is placed in a horizontal rotator, and the rotator is used for
turning the beam during production to alternately align three of the four sides of
the beam facing the concrete spray gun and the surfacing disc so as to achieve a U-shape
cored beam structure.
4. A method as claimed in any of the claims 1...3, characterized in that the mold structure is fabricated by winding plastic material, thin steel
sheet or like material over elongated bars positioned so as to achieve a desired shape
of the mold.