[0001] The invention relates to a device for the support of concrete slab formwork, and
in particular to a device for the support of concrete slab formwork wherein the device
comprises at least one joist. The invention also relates to an assembly for the support
of floor formwork. The invention further relates to a method for the support of floor
formwork.
[0002] With the systems currently in use, each of a plurality of joists is supported by
struts, also referred to as constructiles, lifted upward from a lower storey floor
and with the aid of an adjusting device on the struts adjusted to the correct height.
In order to keep the joists and the struts in place, they should also be shored.
[0003] This lifting of the individual joists and their adjustment to the correct height
and shoring them is a heavy and particularly time-consuming and labour-intensive job.
Especially if a camber in the formwork has to be taken into account. In addition,
the manipulation of the heavy beams and struts entails a safety hazard.
[0004] It is an object of the present invention to propose a device, an assembly and a method
for supporting formwork for storey floors, wherein the support can be provided and
adjusted simply and quickly without requiring much physical exertion, and wherein
the safety hazard can be reduced considerably.
[0005] This object is achieved by means of a device for the support of concrete slab formwork,
comprising at least one joist, wherein the at least one joist is assembled with girders
to form a framework. With the device according to the invention, the joists together
with the girders form a complete framework. The framework is put in place with the
aid of, for example, a hoisting gear. Subsequently the struts may be placed in a simple
manner and adjusted. This can take place essentially without load as the struts are
not required to carry the weight of the joists during their placement and adjustment
to the correct height, as a consequence of which there is no need for shoring, and
the task can be completed quickly without heavy physical work. Moreover, the safety
hazard is reduced to a minimum.
[0006] When the device is embodied such that at least one of the girders is removable, the
device can be removed in a simple manner and used again with a following storey floor.
By moving the struts after an initial setting of the storey floor from the joists
to the formwork, the device becomes available again and may be removed, for example,
by a hoisting gear. The struts are in any case moved regularly for the purpose of
discharging stress during setting. By subsequently detaching one of the girders, a
construction is obtained in the form of a fork that may be removed further in its
entirety. The tines of the fork are formed by the joists. The device may then be detached
from the walls and removed in the direction parallel to the joists, without disturbing
the struts.
[0007] A simple and flexible device is obtained if the device is provided with fastening
means for fastening the girders to walls supporting the floor. This makes the device
very stable and thus allows the struts to be provided and adjusted very simply.
[0008] In a preferred embodiment, the fastening means comprise braces, provided with a horizontal
surface for receiving the girders, and which are to be removably fastened to the walls.
In a manner generally known, the braces can take girders of various lengths, so that
said braces are reusable in different systems according to the invention that are
dimensioned in accordance with, for example, buildings of different sizes.
[0009] If the braces are to be fastened to the wall by means of a bolt connection that projects
through a slotted hole in the brace, wherein the slotted hole is provided with a sloping
portion for dismantling the device after the floor has been constructed, the device
can be dismantled in a simple manner once the storey floor has been laid. For example,
loosening the bolts in the slotted hole allows the device, guided by the bolt and
the slope of the slotted hole to be lowered and simultaneously to be moved horizontally,
so as to release it from the formwork and at the same time from the cross-sectional
side of the storey floor.
[0010] In a preferred embodiment of the device according to the invention, the orientation
of the at least one joist, when the device is fastened to the walls, is essentially
parallel with the walls and the girders are substantially perpendicular thereto. This
embodiment is simple to construct and also simple to operate.
[0011] The joists are preferably made of aluminium. This provides a light but sufficiently
strong device.
[0012] In another embodiment, the device according to the invention comprises at the cross-sectional
end a peripheral formwork. This is simply mounted to the device and serves as enclosure
formwork. In this context, a cross-sectional end is understood to be the side at an
end of the walls.
[0013] Advantageously, a filling plate is provided at the peripheral formwork for filling
up a gap between the peripheral formwork and the supporting formwork. It is often
not possible to make the supporting formwork to precisely the desired size. The supporting
formwork will therefore always be slightly too small. The ensuing gap may be filled
up by mounting a filling plate on the device according to the invention.
[0014] The device according to the invention is further especially suitable to be provided
with a guard rail at a cross-sectional end. There will then be no need to fix this
to the wall separately.
[0015] The device according to the invention is particularly suitable for using in connection
with a formwork comprising concrete formwork floor slabs, also referred to as broad
slab floors.
[0016] In a preferred embodiment, the device can be dismantled so as to reuse the various
components. For example, especially the joists can be reused in a different device
that is suitable for floors with a different distance between the walls.
[0017] If a great distance has to be spanned, thus if the walls are particularly long, it
is preferable to use a combination of two of the above-described devices.
[0018] The device according to the invention is advantageously provided with a hoisting
structure to aid with moving the device. This makes it very simple to position and
reposition the device.
[0019] In a preferred embodiment of the invention, two devices according to the invention
are used for the support of the formwork of a storey floor. If the storey floor is
very long, it is advantageous to use two devices according to the invention, while
in addition providing joists that are supported by at least one girder of each of
the two devices, and which thereby extend the support.
[0020] The above-mentioned object of the invention is further achieved by a method for the
support of formwork for storey floors, wherein the storey floors are supported by
at least two walls situated opposite each other, wherein the method comprises the
steps of:
- positioning at pre-determined positions in the walls a device or assembly according
to the invention,
- positioning struts under the device or the assembly,
- providing the formwork,
- pouring the storey floor,
- after a first setting of the storey floor removing the struts from the device or the
assembly to the formwork,
- removing one of the girders from the device or from each of the systems of the assembly,
and
- removing the device or the assembly from the walls.
[0021] The device according to the invention will now be further elucidated by the description
of a preferred embodiment of the invention, and also with reference to the appended
drawing, in which:
Fig. 1 shows a perspective view of the joists and girders of a device according to
the invention,
Figures 2a, b and c show perspective views of a brace, mounted to a wall, with a portion
of a girder,
Figures 3a, b and c show perspective views of a portion of a device according to the
invention with a peripheral formwork, a filling plate and a guard fence,
Fig. 4 shows a perspective view of a device according to the invention, provided with
a hoisting structure, and
Fig. 5 shows a perspective view of a device according to the invention between two
walls, embodied in two parts.
[0022] Referring first to Fig. 1, which shows a frame work of a device for supporting formwork
for storey floors according to the invention, comprising five joists 1, and two girders
2. This frame work is mounted to two walls 3, both extending parallel with the joists
2.
[0023] Mounting to the walls 3 takes place with the aid of four braces 4, see Fig. 2a. With
the aid of a bolt-and-nut connection 8, a brace is fastened to each of the two ends
of the two girders 2. The bolt for the connection between brace 4 and girder 2 passes
through a slotted hole in the brace 4, allowing an adjustment in the event of dimensional
discrepancies between the girder 2 and the distance between the two walls 3, see Fig.
2b. The braces 4 are mounted to the walls 3, also by means of a bolt-and-nut connection
7. To each wall 3 two braces 4 are mounted, such that both girders 2 are fastened
to the two walls 3. The bolts for mounting the braces 4 to the walls 3 are provided
in the walls 3 at the correct height to position the joists at the desired height
to serve as support for the formwork for the storey floor.
[0024] When the frame work is positioned, that is to say mounted to the walls, struts can
be positioned under the joists in order to support the formwork and the storey floor
to be poured. As the joists are completely fixed in the desired position, the struts
are very simple to position without the necessity of balancing movable joists and
of the usual shoring of the struts in combination with the joists.
[0025] The bolts for mounting the braces 4 to the walls 3 pass through slotted holes 6 in
the braces, see Fig. 2a and Fig. 2b. These slotted holes comprise a sloping portion
and an adjoining horizontal portion. When mounting the device to the walls 3, the
bolts are substantially in the lower part of the sloping portion of the respective
slotted holes 6. After the storey floor has been poured and is set, the removal of
the struts is just as simple as their positioning. The device is still fixed. Subsequently,
after the nuts 7 have been loosened, the device is lowered and moved forward, guided
by the bolts in the slotted holes. This moving may take place by means of a hoisting
structure, a preferred embodiment of which will be described below. This movement
releases the device from the poured storey floor and from the formwork and is now
essentially supported by the hoisting structure. By loosening the nuts 8, the braces
4 can be released from the walls 3. The device is now freely suspended in the hoisting
device and may be removed and, when the walls 3 have been built to the correct height
for the next storey, may be again mounted to the walls for the support of the formwork
for the next storey floor.
[0026] As can be seen in Fig. 1, at one end of the outer joists 1 is provided with corner
sections 9. The ends of the other joists that are at the side where the corner sections
9 are provided, are equipped with fastening pins 10. When the device is mounted to
the walls 3, the joists 1, where corner sections 9 and fastening pins 10 are provided,
project outside the end of the walls 3. This projecting portion is used for mounting
a peripheral fence. To this end two girders 11 are placed on the joists, on which
a floor 12 is fastened. To the corner sections 9 posts 15 are fastened and to the
fastening pins 10 uprights 14 are fastened. The posts 15 and uprights 14 are provided
with handrails 13. Girders 11, floor 12, railings 13, uprights 14 and posts 15 together
form a guard fence which, when mounted forms part of the device and may therefore
be placed integrally with the device, may be mounted to the wall, be removed and hoisted
to the next floor to subsequently be placed there.
[0027] The device shown as example of a preferred embodiment in Figures 1-3, is further
provided with a peripheral formwork 16, an adjusting beam 17 and a filling plate 18.
Peripheral formwork 16 forms the enclosing formwork between the walls 3. Adjusting
beam 17 serves as uppermost part of the peripheral formwork. If the height of the
peripheral formwork has to be adjusted in situ, another adjusting beam 17 of a different
height is provided. Since the formwork supported by the device rarely has the precise
dimensions, it will in the direction parallel to the walls 3 almost always be slightly
smaller than the desired size. This difference is bridged by the filling plate 18.
[0028] Fig. 4 shows the device according to an embodiment of the invention, wherein the
device comprises a hoisting structure. To this end posts 15 are fastened to corner
sections 9, such that posts 15 may be fixed in corner sections 9 in a vertical, as
well as in a substantially horizontal position. In fig. 4 posts 15 are shown in the
horizontal position. The pivoting point is then chosen such that the posts 15 in this
position project above the new storey floor. At a position on the posts 15 that lies
approximately in the device's centre of gravity, the posts 15 are provided with hoisting
hooks 19. For reinforcement purposes, a rod 20 is provided between the hoisting hooks
19. The entire device can now be moved with the aid of a hoisting mechanism, such
as a crane.
[0029] Fig. 5 shows a device according to the present invention, which is an assembly of
two (sub)systems as described above, with reference also to Figures 1-4. The subsystems
are embodied such that the joists of the two subsystems overlap to some extend, so
that in the overlap they lie next to each other. In that case, naturally, only the
outer systems are provided with peripheral formwork and guard fence. Such a device
is used when the length of the floor to be poured is too great to be spanned by one
sub-device. If the distances to be spanned are greater still, additional joists may
be provided, supported by at least one girder of each of the two systems.
[0030] Connections and fastenings mentioned above but not specified, are considered to be
known to the person of average skills in the art. Connections and fastenings are detachable
to allow reuse of the components mentioned in systems of different dimensional requirements,
or to make reuse more simple.
1. A device for the support of concrete slab formwork comprising at least one joist (1),
characterised in that the at least one joist (1) is assembled with girders (2) to form a frame work.
2. A device according to claim 1, characterised in that at least one of the girders is removable.
3. A device according to claim 1 or 2, characterised in that the device is provided with fastening means (4) for fastening the girders (2) to
walls (3) supporting the floor to be constructed.
4. A device according to claim 3, characterised in that the fastening means comprise braces (4), each provided with a horizontal surface
for receiving the girders (2), and which braces (4) are to be removably fastened to
a supporting wall (3).
5. A device according to claim 4, characterised in that the braces (4) are to be fastened to the wall (3) by means of a bolt connection that
projects through a slotted hole (6) in the brace (4), wherein the slotted hole (6)
is provided with a sloping portion for dismantling the device after the floor has
been constructed.
6. A device according to one of the claims 1 to 5, characterised in that when the device is fastened to the walls (3), the at least one joist (1) is essentially
parallel with the walls (3) and the girders (2) are substantially perpendicular thereto.
7. A device according to one of the claims 1 to 6, characterised in that the joists (1) are made of aluminium.
8. A device according to one of the claims 1 to 7, characterised in that the device comprises at the cross-sectional end a peripheral formwork (16, 17).
9. A device according to claim 8, characterised in that a filling plate (18) is provided at the peripheral formwork (16, 17) for filling
up a gap between the peripheral formwork and the supporting formwork.
10. A device according to one of the claims 1 to 9, characterised in that at one cross-sectional end the device is provided with a guard fence (11, 12, 13,
14, 15).
11. A device according to one of the claims 1 to 10, characterised in that the supported formwork comprises concrete formwork floor slabs.
12. A device according to one of the claims 1 to 11, characterised in that the device is provided with a hoisting structure (9, 15, 19, 20) to aid with moving
the device.
13. A device according to one of the claims 1 to 12, characterised in that the device can be dismantled so as to reuse the various components.
14. An assembly for the support of floor formwork, characterised in that the assembly comprises two devices according to one of the claims 1 to 13.
15. An assembly for the support of floor formwork, characterised in that the assembly comprises two devices according to one of the claims 1 to 13, wherein
additionally joists are provided, which are supported by at least one girder (2) of
each of the two devices.
16. A method for the support of floor formwork, wherein the method comprises the steps
of:
- positioning at pre-determined positions in the walls a device or assembly according
to the invention,
- positioning struts under the device or the assembly,
- providing the formwork,
- pouring the storey floor,
- after a first setting of the storey floor removing the struts from the device or
the assembly to the formwork,
- removing one of the girders from the device or from each of the systems of the assembly,
and
- removing the device or the assembly.