Field of the invention
[0001] The present invention relates to an apparatus for forming the edge of a concrete
floor slab panel, a concrete floor slab panel comprising the apparatus, a concrete
floor comprising the apparatus, a method of manufacturing a concrete floor slab panel
and a method of manufacturing a concrete floor.
Background to the invention
[0002] Concrete floor slabs are generally cast as adjoining slab panels and each slab panel
is cast inside a formwork; this formwork defines a space in which to cast the concrete.
The formwork may be constructed from timber, steel, aluminium, plastic or the like.
The formwork may be removable, which means it is removed after the concrete has cured.
Alternatively, it may be leave-in-place formwork, which forms part of the resulting
concrete structure, for example by providing at least part of an edge of a resulting
concrete slab panel.
[0003] The formwork generally comprises one or more upright elongate divider plates, which
the concrete is cast against. The divider plates ensure that the concrete is contained
within the desired space. When a number of floor slab panels are cast next to one
another to form a concrete floor or slab, the divider plates generally sit in between
adjacent slab panels, and dowels or dowel plates, attached to the divider plates,
are used to connect the slab panels together in order to transfer loads across the
joint.
[0004] During the casting of a concrete floor slab panel comprising leave-in-place formwork,
the formwork should be positioned in such a way that the upper edges of the formwork
coincide with the finished floor level (FFL), i.e. the level of the upper surface
of the finished concrete floor slab.
[0005] The slab and formwork rest on a subbase. If the subbase level (SBL) varies, the formwork
will rest on the subbase's highest point. Because of this, it is common practice in
casting concrete floors to allow around 15 - 25 mm for clearance. Concrete floor slab
thicknesses are usually in the range of 150 to 200 mm. Formwork can be manufactured
to desired thickness specifications, which is commonly done in 5 mm increments. If
it is desired to cast a concrete slab with a thickness of, for example, 180 mm, formwork
with a depth of 155 - 165 mm is normally used. In order to achieve the desired finished
floor level (FFL), a divider plate can be suspended at the desired FFL using suspension
means. Such suspension means can, for example, be a jack, or pins may be placed on
both sides of the divider plate and studs, which are commonly present in an apparatus
for forming the edge of a concrete floor slab, may be welded to these pins, thus suspending
the divider plate at the desired FFL. In addition, wedges, adjustable feet and the
like can be used to position the formwork in the desired manner against the subbase
and hold it in place whilst the concrete is cast. However, in these known systems,
when concrete is cast into a formwork comprising a divider plate in an elevated position,
there will be a gap between the subbase and the divider plate, and some of the concrete
will flow through the gap. This can negatively affect the structural soundness of
the joint between neighbouring concrete slab panels, and can require rework to remove
excessive spillage.
[0006] After casting, concrete slabs display normal drying shrinkage. This shrinkage may
be exacerbated when the temperature of the concrete is reduced, for example in the
case of floor slabs for freezer stores. The shrinkage of concrete floor slabs is a
slow process: it can take up to two years for a concrete slab to stop shrinking. The
shrinkage of concrete slab panels generally results in the opening of the joints between
the slab panels, due to each concrete slab panel shrinking away from the joint in
a direction generally perpendicular to the longitudinal axis of the joint. The type
of joint which is adapted to accommodate such shrinking, or contraction, of a concrete
slab panel on one or each side of the joint is known as a "contraction joint". This
is as opposed to an "expansion joint", which is adapted to accommodate expansion of
a concrete slab panel on one or each side of the joint where the slab panels are cast
with a preset gap between them, to allow thermal expansion of the slab panel, after
contraction of the slab panel due to curing has taken place.
[0007] EP 1389648 describes an apparatus for forming the edge of a concrete floor slab panel, the apparatus
comprising a divider plate with a plurality of apertures, dowels for engaging through
the apertures and sleeves for applying to the dowels, in which the divider plate or
dowel or top strip is provided with means to adjust the height thereof above the subbase.
These height adjustment means take the form of a supporting leg together with means
for attaching the leg to the divider plate or dowel or top strip at a selected height.
The leg is positioned alongside the divider plate or dowel or top strip, and is attached
to the divider plate or dowel or top strip either
via a separate lock means, which is passed through a vertical slot formed in the leg
or the divider plate or top strip, or
via a dowel plate. The effect of this set-up is to allow vertical movement of the joint
assembly parallel to the leg, which therefore adjusts the height of the joint assembly
relative to the subbase. However, when the divider plate in this apparatus is moved
upwards relative to the leg, a gap is created between the subbase and the divider
plate. Therefore, when concrete is cast into a formwork comprising the apparatus in
its elevated position, some of the concrete will flow through the gap, which can negatively
affect the structural soundness of the joint between neighbouring concrete slab panels
and can require rework to remove excessive spillage. Furthermore, the lower part of
the divider plate is not secured to the subbase at any point. The divider plate is
only restricted in horizontal movement perpendicular to the thrust of the concrete
against the divider plate where the height adjustment leg is fitted.
[0008] FR 2964131 describes a formwork height adjusting device which comprises a support base, a divider
plate, a backplate, and spaced pairs of brackets. The height of the divider plate
above the support base can be adjusted by sliding it up or down relative to the backplate
and the spaced pairs of brackets. This system relies on the clamping force of bolts
and nuts through the spaced pairs of brackets to hold the divider plate at the correct
height to achieve the required FFL. This severely limits the level of precision with
which the desired FFL can be achieved, as is discussed in more detail below. In addition
to this, when concrete finishing equipment (such as heavy ride-on power trowels) traverse
across the top of the joint whilst the concrete is still uncured, it is probable that
the joint may move vertically downwards, resulting in an FFL that is outside of the
specification for the floor. Furthermore, the device in
FR 2964131 contains a large number of separate components, which heightens the complexity and
cost of this joint.
[0009] It is an aim of the present invention to provide an apparatus for forming the edge
of a concrete floor slab panel, embodiments of which can enhance the ease with which
formwork can be assembled, and hence with which concrete floor slabs can be produced,
and which can enhance the performance characteristics of the resulting concrete floor
slabs and maintain the correct and essential FFL.
Statements of the invention
[0010] According to a first aspect of the present invention there is provided an apparatus
for forming an edge of a concrete floor slab panel laid on a subbase, the apparatus
comprising:
a divider plate for bounding a side of the slab panel, the divider plate having first
and second faces; and
an elongate extension, securable along the first face of the divider plate, for sliding
extension to an extended position in which the extension bridges a gap between the
divider plate and the subbase in use;
wherein the apparatus contains no component which, in use, attaches directly to the
second face of the divider plate and which can extend beyond a lower edge of the divider
plate into the gap between the divider plate and the subbase.
[0011] The term "elongate", as used in the context of the extension, means that the extension
has an elongate shape, the longitudinal axis of which is, in use, positioned substantially
parallel to the longitudinal axis of the divider plate, and hence of the apparatus.
[0012] The term "securable along the first face of the divider plate" means that elongate
extension can be secured to the divider plate at two or more locations along the length
of the first face of the divider plate.
[0013] In use, the extension can be moved up and down relative to the divider plate, which
allows the height of the apparatus above the subbase level to be adjusted. The apparatus
therefore allows a range of different formwork heights to be achieved, which can be
continuously variable, by using a single size of divider plate, instead of requiring
a large number of different sizes of divider plates; the different formwork heights
are achieved simply by adjusting the position of the elongate extension relative to
the divider plate. The apparatus of the invention can therefore allow much greater
flexibility than known types of formwork and can allow distributors to stock a much
smaller number of divider plate variants. The production methodology can be changed
from 'make to order' to 'make to stock' which allows a quicker response time to customers.
[0014] As mentioned above, it is known to suspend a divider plate at the desired finished
floor level (FFL) using suspension means such as, for example, a jack. However, in
these known systems, a gap is created between the subbase and the divider plate and
therefore concrete can flow through the gap, which can negatively affect the structural
soundness of the joint between neighbouring concrete slab panels. In the present invention,
during pouring of concrete the extension would normally rest on the subbase. The apparatus
of the invention therefore achieves a range of different formwork heights, which can
be continuously variable, while avoiding a gap between the subbase and the divider
plate which concrete can flow through.
[0015] Furthermore, the apparatus of the invention can achieve a desired finished floor
level (FFL) to a high level of precision; the observed variation is in the order of
mm. Known systems commonly rely on the clamping force of bolts and nuts to support
the weight of the divider plate and hold it in position; in
FR 2964131, for example, the divider plate is clamped in between spaced pairs of brackets which
are held together with bolts and nuts. In practice, in these types of arrangements
the divider plate is prone to sliding down during the finishing process, when concrete
finishing equipment such as heavy ride-on power trowels traverse across the top of
the joint whilst the concrete is still uncured. Hence the resulting FFL is frequently
lower than intended, or varies along the length of the divider plate. The apparatus
of the present invention, on the other hand, can achieve a desired finished floor
level (FFL) to a much higher level of precision, i.e. accurate to within fractions
of a mm.
[0016] In addition to this, the apparatus according to the first aspect of the invention
can be easier to operate than existing apparatus in this field. After the divider
plate has been set up by supporting (e.g. suspending) it at the desired FFL using
support means (which can include suspension means such as, for example, a jack), the
position of the extension relative to the divider plate can, for example, be adjusted
simply by tapping the extension down to the subbase level, or if the extension is
attached to the divider plate via a loose fit it can automatically drop down to the
subbase level.
[0017] Therefore the apparatus can enhance the ease with which concrete floor slab panels
can be produced, can enhance the performance characteristics of the resulting concrete
floor slabs, and can eliminate the need to trim off concrete spillage, which can save
time and reduce waste management costs on site.
[0018] The extension is an essential element of the present invention. In addition, the
extension is obviously suitable for putting the invention into effect.
[0019] In an embodiment, the elongate extension comprises at least an elongate side wall
and an elongate foot.
[0020] In an embodiment, the elongate extension has a substantially L-shaped cross-section.
[0021] In an embodiment, the elongate extension further comprises an elongate return edge
on the elongate foot, resulting in an elongate extension with a substantially J-shaped
cross-section.
[0022] In an embodiment, the elongate extension has a substantially C-shaped cross-section.
[0023] In an embodiment, the position of the extension relative to the divider plate can
be adjusted in a continuous manner. This allows the height of the formwork relative
to the subbase to be adjusted to any desired height, within the range to which the
extension is adjustable relative to the divider plate.
[0024] In an embodiment, the position of the extension relative to the divider plate can
be adjusted in a stepwise manner. The steps can, for example, be arranged to be set
at known intervals which can help in aligning different sections of formwork without
the need to take measurements.
[0025] In an embodiment, at least one of the divider plate and the extension comprises members
adapted to engage with the other. These members can, for example, ensure that the
extension stays attached to the divider plate, ensure that the extension is held in
position relative to the divider plate, and/or prevent the divider plate and extension
from slipping relative to each other. In an embodiment, the divider plate comprises
members adapted to engage with the extension. In an embodiment, the extension comprises
members adapted to engage with the divider plate.
[0026] In an embodiment, the extension is movable between a stowed position and the extended
position and, in the stowed position, the extension cooperates with the divider plate
to provide a frictional resistance to sliding extension. This stowed form can make
the apparatus more convenient to store, transport and handle.
[0027] In an embodiment, the extension is movable between the stowed position and the extended
position along a movement path and the divider plate and the extension are arranged
to cooperate such that the frictional resistance varies along the movement path. In
an embodiment, the movement path comprises a first section of greater resistance in
which extending movement of the extension under gravity is prevented and a second
section of reduced resistance in which extending movement of the extension may occur
under gravity. This means that while having the convenience of a stowed form, the
apparatus is also easy to extend when it is set up as formwork during concrete casting:
once the extension has been extended beyond a certain point relative to the divider
plate it will conveniently slide down to the subbase under gravity, until it comes
to rest on the subbase. In the second section, the extension may for example be attached
to the divider plate via a loose fit, such that, in use, the extension can drop down
to the subbase under gravity while remaining attached to the divider plate.
[0028] In an embodiment, the divider plate and the extension are arranged to cooperate such
that, when the extension is in the stowed position, the extension and the divider
plate are held together by friction means to resist extending movement, but if the
extension is extended by a predetermined distance, the extension can, in use, drop
down to the subbase under gravity while remaining attached to the divider plate. This
can, for example, be achieved by having interference members, such as small embossed
'pips', which protrude from the elongate extension near the lower end of the elongate
extension and interfere with the mating face of the divider plate, thus causing an
interference fit when the elongate extension is in its stowed position. Once the elongate
extension has been lowered sufficiently such that the interference members (e.g. the
'pips') have moved past the lower edge of the divider plate, then no interference
is taking placing and the elongate extension can fall freely under gravity.
[0029] In an embodiment, the divider plate and/or the extension contains a substantially
vertical slot adapted to receive mechanical fastening means. In an embodiment, the
divider plate contains a substantially vertical slot adapted to receive mechanical
fastening means. In an embodiment, the elongate extension contains a substantially
vertical slot adapted to receive mechanical fastening means.
[0030] In an embodiment, the extension is arranged to be attached to the divider plate via
mechanical fastening means. In an embodiment, the mechanical fastening means is a
rivet. Other mechanical fastening means can, for example, include a nut and bolt,
and a screw, a threaded stud (along with a nut) welded to either the divider plate
or elongate extension, a cable-tie, and a spring loaded compression type fastener.
[0031] In an embodiment, the apparatus is arranged to be securable to the subbase. This
arrangement makes the apparatus easier to operate, since it allows the concrete to
be cast without the risk of the apparatus shifting in position (in a substantially
horizontal direction) in the process. This can enhance the ease with which concrete
floor slabs can be produced.
[0032] In an embodiment, the apparatus further comprises a pin; and a wedge; wherein, in
use, the pin can be placed in the ground on the same side of the divider plate as
the elongate extension, and the wedge can be placed between the pin and the elongate
extension and/or the divider plate, in order to secure the apparatus to the subbase
in the desired location. This arrangement allows the apparatus to resist the concrete
thrust caused by concrete cast on the other side of the divider plate from the pin
and wedge, which allows the concrete to be cast without the risk of the apparatus
shifting in position (in a substantially horizontal direction) in the process.
[0033] The wedge, which can be placed between the pin and the elongate extension and/or
the divider plate, can be of any shape, as long as it allows the apparatus to be secured
to the subbase in the desired location.
[0034] In an embodiment, the range over which the extension can be moved relative to the
divider plate is a range of about 50 mm. In use, this movement would generally be
in a substantially vertical direction. Since the height of a concrete floor slab is
usually in the range of 150 to 200 mm, the range of movement of about 50 mm can allow
the full range of common floor slab heights to be achieved with a single size of apparatus.
[0035] In an embodiment, the divider plate is formed from a metal such as, for example,
steel. This can result in a divider plate of high mechanical strength, capable of
withstanding the forces acting upon it during the casting of concrete.
[0036] In an embodiment, the extension is formed from a metal such as, for example, steel,
or from plastic. In an embodiment, the extension is formed from steel.
[0037] In an embodiment, the extension is formed as an elongate extrusion. In an embodiment,
the elongate extrusion has a substantially constant cross-section along its length.
[0038] In an embodiment, the extension comprises a longitudinal fold at the top edge and/or
the lower edge of the extension. Such a fold can, for example, be a longitudinal L-fold,
a longitudinal V-fold or a Dutch fold (where the divider plate is completely folded
back on itself). Such a fold can strengthen the extension.
[0039] The divider plate can be conventional in construction, for example as
EP 1389648 or similar.
[0040] In an embodiment, the divider plate is an elongate flat section of material.
[0041] In an embodiment, the divider plate comprises a longitudinal fold at the top edge
and/or the lower edge of the divider plate. Such a fold can, for example, be a longitudinal
L-fold, a longitudinal V-fold or a Dutch fold (where the divider plate is completely
folded back on itself). Such a fold can strengthen the divider plate.
[0042] In an embodiment, the divider plate comprises one or more apertures. In an embodiment,
the apparatus further comprises one or more dowels or dowel plates for engaging through
the one or more apertures. These act to connect the resulting concrete slab panels
together and to provide a method of load transfer between adjacent slab panels. In
an embodiment, the apertures suitable for receiving the dowels or dowel plates in
the divider plate are located above the upper edge of the elongate extension when
the extension is in its highest position relative to the divider plate (i.e. the extension
is in its fully retracted form). In an embodiment, the extension may be castellated
along its top edge such that it can accommodate the dowels.
[0043] Once cast, concrete slab panels are prone to shrinkage during curing which causes
the edges of the slab panels to separate. This exposes the upper edge, or arris, of
each individual slab panel to damage from loads such as from vehicles, including for
example lorries or forklift trucks, passing across the joint.
[0044] The apparatus, therefore, may comprise further components, which after casting of
the concrete would sit at the surface of the concrete floor. Such components include,
for example, edge rails and top plates.
[0045] In an embodiment, the apparatus further comprises edge rails, which may be supported
by the divider plate. In an embodiment, the apparatus comprises two such edge rails
adjacent to each other. The edge rails can provide protection to the arris of the
cast slab panels and improve the longevity of the slab at the joints.
[0046] The edge rails may be arranged to mate with each other along linear or non-linear
edges. In an embodiment, the edge rails are arranged to mate with each other along
linear edges. In an embodiment, the edge rails are arranged to mate with each other
along non-linear edges.
[0047] In an embodiment, the apparatus further comprises top plates, which may be supported
by the divider plate. In an embodiment, the apparatus comprises two top plates adjacent
to each other, referred to as first and second top plates. The top plates can provide
protection to the arris of the cast slab panels and improve the longevity of the slab
at the joints.
[0048] In an embodiment, the apparatus comprises first and second top plates which are arranged
to mate with one another along linear edges.
[0049] In an embodiment, the apparatus comprises first and second top plates which are arranged
to mate with one another along non-linear edges, such as, for example, shown in
FR 2785632.
[0050] In an embodiment, the apparatus further comprises first and second supports, the
first support being attached to or attachable to the divider plate and to the first
top plate, and the second support being attached to or attachable to the second top
plate.
[0051] In an embodiment, the first support comprises a facing edge which faces the second
support, and the edge of the first top plate is offset from the facing edge of the
first support, along the direction in which the top plates can move apart, so that,
when in use between two shrinking concrete slab panels, the gap which opens up between
the top plates is offset from the gap which opens up between the supports and the
gaps do not overlap.
[0052] In this embodiment, when the apparatus is used as a joint between concrete floor
slab panels, if, as the concrete shrinks, the first and second top plates move apart
in the direction perpendicular to the longitudinal axis of the joint, the elongate
gap which is formed between the first and second top plates is only as deep (vertically)
as the first and second top plates. This gap is offset from the gap which opens up
between the supports, and which extends down to the subbase between the two shrinking
concrete slab panels. The gap which opens up between the first and second top plates
is offset from the gap which opens up between the supports in the same axial plane.
The two gaps do not overlap, so this joint does not contain a continuous path from
the surface to the subbase. Therefore debris and vermin cannot get into the full depth
shrinkage gap through the surface gap between the first and second top plates. Shrinkage
gaps can commonly be filled in with a filler rod and a sealant resin. However, this
is a labour intensive process, and it usually does not provide a final solution due
to the long time it takes for concrete slabs to stop shrinking. The filler rod and
sealant resin are usually applied before the concrete floor slabs have stopped shrinking,
and as they continue to shrink the gap can reopen since the sealant is unable to stretch
enough to accommodate the larger shrinkage gap. In addition to this, the sealant is
costly and tends to age and requires removal before fresh sealant can be fitted. The
embodiment wherein the gap which opens up between the first and second top plates
does not overlap with the gap which opens up between the supports does not contain
a continuous path from the surface to the subbase. This apparatus, therefore, can
dispense with the need to use filler rods and/or a sealant resin.
[0053] In an embodiment, the edge rails, top plates and/or supports further comprise anchor
means for embedding in the concrete. The anchor means become embedded in the concrete
during curing and fix the edge rails, top plates and/or supports in position.
[0054] Some or all of these anchor means may also be welded to pins, placed on both sides
of the divider plate, to suspend the divider plate at the desired finished floor level
(FFL) before concrete is cast. The pins would, of course, be placed or cut off in
such a way that they do not stick out above the FFL. This technique of suspending
the divider plate at the desired FFL can be used as an alternative to or in combination
with other support means, which can include suspension means such as, for example,
a jack.
[0055] In an embodiment, the edge rails, top plates and/or supports are attached together
with yieldable fixings. These fixings fail under tension as shrinking occurs during
the curing process and the edge rails, top plates and/or supports of adjacent slabs
are drawn apart.
[0056] In an embodiment, the yieldable fixings comprise low tensile bolts. Examples of such
low tensile bolts are bolts formed from nylon, the threads of which will become stripped
under shrinkage forces, or the shanks of which will fail under tension.
[0057] The apparatus according to the first aspect of the invention can be used to form,
for example, prefabricated four-way intersections, three-way "T" intersections, corner
units and loading dock corners.
[0058] According to a second aspect of the present invention there is provided a concrete
floor slab panel comprising the apparatus according to the first aspect of the invention.
[0059] According to a third aspect of the present invention there is provided a concrete
floor comprising the apparatus according to the first aspect of the invention.
[0060] According to a fourth aspect of the present invention there is provided a method
of manufacturing a concrete floor slab panel, comprising the steps of
- (i) setting up the apparatus according to the first aspect of the invention to form
at least part of an edge of a space for casting concrete; and
- (ii) casting concrete in the space.
[0061] In an embodiment, step (i) comprises supporting the apparatus using support means.
In an embodiment, the support means comprise suspension means, such as e.g. a jack.
[0062] According to a fifth aspect of the present invention there is provided a method of
manufacturing a concrete floor, comprising the steps of
- (i) setting up the apparatus according to the first aspect of the invention to form
at least part of an edge of a space for casting concrete; and
- (ii) casting concrete in the space;
wherein steps (i) and (ii) are performed more than once.
[0063] In an embodiment, step (i) comprises supporting the apparatus using support means.
In an embodiment, the support means comprise suspension means, such as e.g. a jack.
[0064] Throughout the description and claims of this specification, the words "comprise"
and "contain" and variations of the words, for example "comprising" and "comprises",
mean "including but not limited to", and do not exclude other moieties, additives,
components, integers or steps. Moreover the singular encompasses the plural unless
the context otherwise requires: in particular, where the indefinite article is used,
the specification is to be understood as contemplating plurality as well as singularity,
unless the context requires otherwise.
[0065] Preferred features of each aspect of the invention may be as described in connection
with any of the other aspects. Other features of the invention will become apparent
from the following examples. Generally speaking the invention extends to any novel
one, or any novel combination, of the features disclosed in this specification (including
any accompanying claims and drawings). Thus features, integers, characteristics, compounds,
chemical moieties or groups described in conjunction with a particular aspect, embodiment
or example of the invention are to be understood to be applicable to any other aspect,
embodiment or example described herein unless incompatible therewith. Moreover unless
stated otherwise, any feature disclosed herein may be replaced by an alternative feature
serving the same or a similar purpose.
[0066] Where upper and lower limits are quoted for a property, then a range of values defined
by a combination of any of the upper limits with any of the lower limits may also
be implied.
[0067] The following numbered clauses also define aspects of the invention and related optional
features:
- 1. Apparatus for forming an edge of a concrete floor slab panel laid on a subbase,
the apparatus comprising:
a divider plate for bounding a side of the slab panel, the divider plate having first
and second faces; and
an elongate extension, securable along the first face of the divider plate, for sliding
extension to an extended position in which the extension bridges a gap between the
divider plate and the subbase in use;
wherein the apparatus contains no component which, in use, attaches directly to the
second face of the divider plate and which can extend beyond a lower edge of the divider
plate into the gap between the divider plate and the subbase.
- 2. The apparatus of clause 1, wherein the elongate extension comprises at least an
elongate side wall and an elongate foot.
- 3. The apparatus of clause 2, wherein the elongate extension further comprises an
elongate return edge on the elongate foot, resulting in an elongate extension with
a substantially J-shaped cross-section.
- 4. The apparatus of any one of the preceding clauses, wherein the position of the
extension relative to the divider plate can be adjusted in a continuous manner.
- 5. The apparatus of any one of the preceding clauses, wherein at least one of the
divider plate and the extension comprises members adapted to engage with the other.
- 6. The apparatus of any one of the preceding clauses, wherein the extension is movable
between a stowed position and the extended position and wherein, in the stowed position,
the extension cooperates with the divider plate to provide a frictional resistance
to sliding extension.
- 7. The apparatus of clause 6, wherein the extension is movable between the stowed
position and the extended position along a movement path and wherein the divider plate
and the extension are arranged to cooperate such that the frictional resistance varies
along the movement path.
- 8. The apparatus of clause 7, wherein the movement path comprises a first section
of greater resistance in which extending movement of the extension under gravity is
prevented and a second section of reduced resistance in which extending movement of
the extension may occur under gravity.
- 9. The apparatus of clause 8, wherein the divider plate and the extension are arranged
to cooperate such that, when the extension is in the stowed position, the extension
and the divider plate are held together by friction means to resist extending movement,
but if the extension is extended by a predetermined distance, the extension can, in
use, drop down to the subbase under gravity while remaining attached to the divider
plate.
- 10. The apparatus of any one of the preceding clauses, wherein the divider plate and/or
the extension contains a substantially vertical slot adapted to receive mechanical
fastening means.
- 11. The apparatus of any one of the preceding clauses, wherein the apparatus is arranged
to be securable to the subbase.
- 12. The apparatus of clause 11, wherein the apparatus further comprises
a pin; and
a wedge;
wherein, in use, the pin can be placed in the ground on the same side of the divider
plate as the extension, and the wedge can be placed between the pin and the extension
and/or the divider plate, in order to secure the apparatus to the subbase in the desired
location.
- 13. The apparatus of any one of the preceding clauses, wherein the range over which
the extension can be moved relative to the divider plate is a range of about 50 mm.
- 14. A concrete floor slab panel comprising the apparatus according to any one of clauses
1-13.
- 15. A concrete floor comprising the apparatus according to any one of clauses 1-13.
- 16. A method of manufacturing a concrete floor slab panel, comprising the steps of
- (i) setting up the apparatus according to any one of clauses 1-23 to form at least
part of an edge of a space for casting concrete; and
- (ii) casting concrete in the space.
Specific description
[0068] Embodiments of the present invention will now be further described with reference
to the accompanying figures, of which:
Figure 1 shows a perspective view of an embodiment of the apparatus of the invention,
with the extension in a retracted position relative to the divider plate.
Figure 2 shows a perspective view of the embodiment in Figure 1, with the extension
in a retracted position relative to the divider plate, together with suspension means
in the form of a jack.
Figure 3 shows a perspective view of the embodiment in Figure 1, with the extension
in an extended position relative to the divider plate, together with a jack, a pin
and wedges.
Figure 4 shows an area cross-sectional view of the embodiment in Figure 1 perpendicular
to its length, with the extension in a retracted position relative to the divider
plate.
Figure 5 shows an area cross-sectional view of the embodiment in Figure 4, with the
extension in an extended position relative to the divider plate.
Figure 6 shows a total cross-sectional view of the embodiment in Figure 1 perpendicular
to its length, with the extension in an extended position relative to the divider
plate, together with the subbase, a jack, two pins and wedges, before concrete has
been cast.
Figure 7 shows a total cross-sectional view of the embodiment in Figure 6, after concrete
has been cast on one side of the apparatus.
Figure 8 shows a total cross-sectional view of the embodiment in Figure 7, after concrete
has been cast on one side of the apparatus, and the jack, two pins and wedges have
been removed.
Figure 9 shows a total cross-sectional view of the embodiment in Figure 8, after concrete
has been cast on both sides of the apparatus.
[0069] As shown in Figures 1 to 5, an elongate extension
2 is movably secured to one face of divider plate
1. Divider plate
1 is an elongate flat section of material. The extension
2 is elongate and comprises an elongate side wall
2a, an elongate foot
2b and an elongate return edge
2c on the elongate foot
2b, resulting in an elongate extension
2 with a substantially J-shaped cross-section. Extension
2 has a substantially constant cross-section along its length.
[0070] The elongate extension
2 is movable relative to the divider plate
1 between a fully retracted position and a fully extended position. The extension
2 can also be moved to a position anywhere between these two extremes.
[0071] The extension
2 contains substantially vertical slots
3 at regular intervals. The slots
3 are adapted to receive rivets
4 which are also connected to the divider plate
1.
[0072] In the embodiment shown in Figures 1 to 9, the position of the extension
2 relative to the divider plate
1 can be adjusted in a continuous manner, and the extension
2 is attached to the divider plate
1 via a loose fit. The extension
2 has a stowed position, where the extension
2 and the divider plate
1 are held together by friction means (not shown), but if the extension
2 is moved down relative to the divider plate
1 by a predetermined distance (i.e. towards a more extended form), the extension
2 can drop down to the subbase under gravity while remaining attached to the divider
plate
1.
[0073] Divider plate
1 comprises apertures
6 along its length at regular intervals. The apertures
6 are adapted to receive dowel plates
7. On one side of the divider plate
1, the dowel plates
7 are encased in dowel sleeves
8, which, in use, allow movement of the concrete as it sets and shrinks.
[0074] The apparatus further comprises edge rails
5 supported by divider plate
1. Anchor means
9 extend out from the edge rails
5 in the general direction where, in use, the concrete would be poured.
[0075] Figures 2, 3, 6 and 7 also show a jack
10, which does not form part of the apparatus of the invention, but which can be used
to suspend the divider plate
1 at the desired finished floor level (FFL) before concrete is cast. The jack
10 can, for example, have a removable threaded end which fits through apertures in the
edge rails
5. The threaded end can be secured to the edge rails
5 by securing it with a wing nut on the other side from the jack
10, while on the side of the jack
10, the threaded end fits inside the jack's square box section which runs up and down
the threaded bar, allowing the height of the apparatus
1 relative to the subbase to be adjusted.
[0076] Figures 3, 6 and 7 also show pins
11a, 11b and wedges
12, which do not form part of the apparatus of the invention, but which can be used to
secure the apparatus to the subbase in the desired location.
[0077] In use, as shown in Figures 6 to 9, the divider plate
1 is suspended at the desired FFL using support means, which can include suspension
means such as, for example, a jack
10. The jack
10 is secured to the subbase via a pin
11b.
[0078] At this stage, the extension
2 can be in its stowed form. The extension
2 is then moved down relative to the divider plate
1 by a predetermined distance, past the friction means which was holding it in place
(not shown); after this the extension
2 can drop down to the subbase under gravity, while remaining attached to the divider
plate
1 via a loose fit.
[0079] An additional pin
11a is then placed in the ground on the same side of the divider plate
1 as the extension
2 and the jack
10. Wedges
12 are placed between the pin
11a and the extension
2 and/or the divider plate
1, in order to secure the apparatus to the subbase in the desired location and prevent
movement caused by the thrust of the concrete.
[0080] The apparatus will form at least part of an edge of a space for casting concrete.
The entire edge may be formed by the apparatus, and the remaining edges may also be
formed by further units of the apparatus. Once the space for casting concrete has
been defined by the edges, i.e. the formwork has been set up, concrete is poured into
the space.
[0081] As shown in Figures 6 to 9, concrete is first cast on the other side of the divider
plate
1 from the extension
2, the jack
10, the pins
11a, 11b and the wedges
12 (see Figure 7). After this concrete has set sufficiently, the jack
10, the pins
11a, 11b and the wedges
12 are removed (see Figure 8). The jack
10 is, for example, detached from its threaded end (which is still attached to the edge
rails
5) and the threaded end is unscrewed, while the wing nut stays in place in the concrete
on the other side. After this concrete is cast on the remaining side of the apparatus
(see Figure 9).
[0082] The apparatus of the invention can alleviate the need to manufacture, transport and
stock a large number of different sizes of divider plates to suit all customer needs.
Instead, a desired formwork height can be achieved by using a single size of divider
plate, while avoiding a gap between the subbase and the divider plate which concrete
can flow through. Furthermore, the apparatus of the invention can be easier to operate
than existing apparatus in this field, and can achieve a desired finished floor level
(FFL) to a high level of precision. Therefore the apparatus can enhance the ease with
which concrete floor slab panels can be produced, and can enhance the performance
characteristics of the resulting concrete floor slabs.
1. Apparatus for forming an edge of a concrete floor slab panel to be laid on a subbase,
the apparatus comprising:
a divider plate (1) for bounding a side of the slab panel, the divider plate (1) having
first and second faces;
an elongate extension (2), securable along the first face of the divider plate (1),
for sliding extension to an extended position in which the extension (2) bridges a
gap between the divider plate (1) and the subbase in use, wherein the longitudinal
axis of the elongate extension (2) is, in use, positioned substantially parallel to
the longitudinal axis of the divider plate (2); and
support means for suspending the divider plate (1) at a desired finished floor level,
wherein the apparatus contains no component which, in use, attaches directly to the
second face of the divider plate (1) and which can extend beyond a lower edge of the
divider plate (1) into the gap between the divider plate (1) and the subbase; and
wherein the elongate extension is attached to the divider plate via a loose fit such
that, in use, it is configured to automatically drop down to the subbase from a stowed
position to an extended position.
2. The apparatus of claim 1, wherein the elongate extension is attached to the divider
plate by mechanical fastening means providing said loose fit and configured to permit
movement of the elongate extension relative to the divider plate between the stowed
position and the extended position.
3. The apparatus of claim 1 or claim 2, wherein at least one of the divider plate and
the elongate extension comprises members adapted to engage with the other to provide
said attachment between the elongate extension and the divider plate.
4. The apparatus of any of claims 1 to 3, wherein in the stowed position the elongate
extension cooperates with the divider plate to provide a frictional resistance to
sliding extension.
5. The apparatus of any preceding claim, wherein the elongate extension (2) comprises
at least an elongate side wall (21) and an elongate foot (2b).
6. The apparatus of claim 5, wherein the elongate extension further comprises an elongate
return edge (2c) on the elongate foot (2b), resulting in an elongate extension (2)
with a substantially J-shaped cross-section.
7. The apparatus of any one of the preceding claims, wherein the position of the elongate
extension (2) relative to the divider plate (1) can be adjusted in a continuous manner.
8. The apparatus of any one of the preceding claims, wherein at least one of the divider
plate (1) and the extension (2) comprises members adapted to engage with the other.
9. The apparatus of any one of the preceding claims, wherein the divider plate (1) and/or
the extension (2) contains a substantially vertical slot (3) adapted to receive mechanical
fastening means (4).
10. The apparatus of any one of the preceding claims, wherein the extension is arranged
to be attached to the divider plate by means of a rivet.
11. The apparatus of any one of the preceding claims, wherein the apparatus is arranged
to be securable to the subbase.
12. The apparatus of claim 11, wherein the apparatus further comprises
a pin (11a,11b); and
a wedge (12);
wherein, in use, the pin (11a,11b) can be placed in the ground on the same side of
the divider plate (1) as the extension (2), and the wedge (12) can be placed between
the pin (11a,11b) and the extension (2) and/or the divider plate (1), in order to
secure the apparatus to the subbase in the desired location.
13. A concrete floor slab panel comprising the apparatus according to any one of claims
1-12.
14. A concrete floor comprising the apparatus according to any one of claims 1-12.
15. A method of manufacturing a concrete floor slab panel, comprising the steps of
(i) setting up the apparatus according to any one of claims 1-13 to form at least
part of an edge of a space for casting concrete, setting up the apparatus including
the steps of:
(a) suspending the divider plate (1) at a desired finished floor level using the support
means;
(b) allowing the elongate extension to automatically drop down from the stowed position
to the extended position; and
(ii) casting concrete in the space.