Note: Descriptions are shown in the official language in which they were submitted.
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A SCAFFOLD BOARD
Field of the Invention
[0001] The present invention relates to a scaffold board.
Background
[0002] The use of scaffolding during construction, demolition, renovation,
maintenance and
other building tasks is well known and wide spread. Scaffolding typically
involves the
temporary construction of a rectilinear framework of vertical standards,
horizontal ledgers and
horizontal transoms. The standards, ledgers and transoms are typically steel
tubes which are
interconnected by clamps. Scaffold boards are laid across the transoms in
order to provide
elevated working platforms. Scaffold boards are usually manufactured from
solid wood or
laminated veneer lumber (LVL).
[0003] There are several disadvantages associated with solid wood and LVL
scaffold boards,
including that: they are relatively expensive; they are relatively heavy; they
are perishable; they
are not UV Light resistant; they are flammable; they are not resistant to
chemical contamination;
they are not resistant to propagation of mould spores and bacteria; and they
are not recyclable.
[0004] United States Patent Publication No. US 2013/0192927 (Application No.
13/754212)
discloses an alternative scaffold board manufactured from poly vinyl chloride
(PVC). The
disclosed board overcomes some of the above mentioned disadvantages (e.g. they
are non-
perishable, UV light resistant and recyclable). However, they have the
significant disadvantage
of high deflection under load. As such they do not meet a variety of
international and Australian
Standards, particularly the deflection test for scaffold boards, which (in
Australia and New
Zealand) requires deflection of less than lOmm over a lm span responsive to a
working load
limit (e.g. 210kg) applied centrally. As a result, this product cannot be used
in Australia, nor the
USA, UK or Canada (which have similar standards) and many other significant
building
markets.
[0005] Another known alternative scaffold board has been manufactured from
fibre reinforced
plastic (FRP). It also overcomes several similar disadvantages of wood/LVL
boards. However,
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it is also a relatively heavy product, is produced from a highly flammable
type of plastic
material, is exceptionally difficult to recycle and has exceptionally high
deflection at moderately
high temperatures. As a result, this product is suitable for only very
specific applications.
[0006] A further known alternative scaffold board has been manufactured from
polypropylene.
It also does also not pass Australian standards. The board is black and
becomes significantly
more flexible in sunlight. It is also able to ignite and transfer a flame.
[0007] Scaffold boards have also been produced from aluminium, which suffer
from similar
disadvantages in terms of relatively high material and production cost and
relatively high weight.
Object of the Invention
[0008] It is an object of the present invention to substantially overcome, or
at least ameliorate,
one or more of the above disadvantages.
Summary of the Invention
[0009] Accordingly, in a first aspect, the present invention provides a
scaffold board of extruded
thermoplastic material, the board including:
a substantially rectangular outer profile defined by a top wall, a bottom wall
and a pair of
side walls; and
a plurality of strengtheners, each extending between an inner surface of the
top wall and
an inner surface of the bottom wall,
wherein each of the strengtheners have:
a middle part oriented normally to the plane of the top wall and the bottom
wall;
a pair of top parts, each extending outwardly from a top of the middle part to
the
inner surface of the top wall in substantially equal and opposite directions
respectively;
and
a pair of bottom parts, each extending outwardly from a bottom of the middle
part
to the inner surface of the bottom wall in substantially equal and opposite
angles.
[0010] The top wall, the bottom wall, the side walls and the strengtheners
preferably extend
longitudinally along a length of the scaffold board.
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[0011] The top wall, the bottom wall, the side walls and the strengtheners are
preferably
integrally formed.
[0012] The pair of top parts of each strengthener preferably defines a
triangular longitudinal
recess with the adjacent inner surface of the top wall. The pair of bottom
parts of each
strengthener preferably defines a triangular longitudinal recess with the
adjacent inner surface of
the bottom wall.
[0013] In one form, a hexagonal longitudinal recess is preferably defined
between adjacent said
strengtheners. In another form, an octagonal longitudinal recess is preferably
defined between
adjacent said strengtheners.
[0014] The top wall, the bottom wall and the side walls are preferably thicker
than the middle
parts, the top parts and the bottom parts.
[0015] The top wall and the bottom wall preferably include textured non-slip
outer surfaces
[0016] The board is preferably extruded from PCV, most preferably type k62 or
k66.
[0017] In a second aspect, the present invention provides a scaffold board of
extruded
thermoplastic material, the board including:
a substantially rectangular outer profile defined by a top wall, a bottom wall
and a pair of
side walls;
a plurality of top triangular hollow recesses extending longitudinally through
the board,
each having one side parallel to the plane of the top wall;
a plurality of bottom hollow triangular recesses extending longitudinally
through the board,
each having one side parallel to the plane of the bottom wall; and
a plurality of hollow hexagonal or octagonal recesses extending longitudinally
through the
board, each being positioned between adjacent opposed pairs of top triangular
recesses and
bottom triangular recesses.
[0018] In one form, the plurality of hollow recesses extending longitudinally
through the board
between adjacent opposed pairs of top triangular recesses and bottom
triangular recesses are
hexagonal. In another form, the plurality of hollow recesses extending
longitudinally through
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the board between adjacent opposed pairs of top triangular recesses and bottom
triangular
recesses are octagonal.
[0019] The top wall, the bottom wall, the side walls are preferably integrally
formed with the top
triangular recesses, the bottom triangular recesses and the
hexagonal/octagonal recesses.
[0020] The top wall and the bottom wall preferably include textured or non-
slip outer surfaces
[0021] The board is preferably extruded from PCV, most preferably type k62 or
k66.
[0022] In a third aspect, the present invention provides a scaffold board of
extruded
thermoplastic material, the board including:
a substantially rectangular outer profile defined by a top wall, a bottom wall
and a pair of
side walls; and
an internal honeycomb strengthening structure, within the top wall, the bottom
wall and
the pair of side walls, defined by a row of longitudinally extending cells,
each of the cells
defined by a 6 or 8 sided polygon with its longest dimension oriented normally
to the plane of
the top wall and the bottom wall.
[0023] In one form, the polygon is a hexagon. In another form, the polygon is
an octagon.
[0024] The top wall, the bottom wall, the side walls and the strengtheners
preferably extend
longitudinally along a length of the scaffold board.
[0025] The top wall, the bottom wall, the side walls and the honeycomb
strengthening structure
are preferably integrally formed.
[0026] The top wall, the bottom wall and the side walls are preferably thicker
than the walls of
the honeycomb strengthening structure.
[0027] The top wall and the bottom wall preferably include textured non-slip
outer surfaces
[0028] The board is preferably extruded from PCV, most preferably type k62 or
k66.
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Brief Description of the Drawings
[0029] Preferred embodiments of the invention will now be described, by way of
examples only,
with reference to the accompanying drawings in which:
[0030] Fig. 1 is a perspective view of an embodiment of scaffold board;
[0031] Fig. 2 is an enlarged cross sectional end view of the scaffold board
shown in Fig. 1;
[0032] Fig. 3 is an enlarged partial detail view of the scaffold board shown
in Fig. 2;
[0033] Fig. 4 is an enlarged cross sectional end view of a second embodiment
of scaffold board.
Detailed Description of the Preferred Embodiments
[0034] Figs. 1 to 3 show a first embodiment of a scaffold board 10 produced by
extrusion from
poly vinyl chloride (PVC) thermo plastic material. As examples, PVC type k62
or k66 is used,
with the following formula per Hundred Parts PVC resin:
Ingredients PHR Range
PVC 100
Calcium Carbonate 0.0 - 25.0
Talc 0.0 - 40.0
Impact Modifier 2.0 - 15.0
Organic Based Stabilizer 4.5 - 7.5
Lubricant 0.4 - 1.2
Processing Aid 0.1 - 1.2
Flame Retardants 0.1 ¨ 15.0
Wax 0.1 - 1.2
UV Stabilizer 0.1 - 0.8
Titanium Di Oxide 1.0 - 7.0
Depends on
Colouring Pigments
Requirements
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[0035] As will be understood by persons skilled in the art, the above
components can be
increased or reduced to tailor the formula to suit particular applications,
climates and
temperature ranges.
[0036] The board 10 is produced in dimensions matching those of existing wood
boards in order
to suit existing scaffolding equipment. The board 10 is 230 mm wide, 39 mm
thick (including
the hot rolled grip discussed below) and produced in 2400 mm and 3600 mm
lengths.
[0037] As best shown in Fig. 2, the board has a substantially rectangular
outer profile defined by
a top wall 12, a bottom wall 14 and pair of side wall 16 and 18. The walls 12,
14, 16 and 18 are
all approximately 4 mm thick. The interior of the board 10 is substantially
hollow aside from a
plurality of strengtheners, indicated generally by the reference numeral 20,
which each extend
between an inner surface of the top wall 12 and an inner surface of the bottom
wall 14.
[0038] The strengtheners 20 each have a pair of top parts 20a and 20b, a
middle part 20c and a
pair of bottom parts 20d and 20e, which are all about 3 mm thick. The top
parts 20a and 20b
each extend the outwardly from the top of the middle part 20c to the inner
surface of the top wall
12 in substantially equal and opposite directions respectively. The bottom
parts 20d and 20e
each extend outwardly from the bottom of the middle part 20c to the inner
surface of the bottom
wall 14 in substantially equal and opposite directions respectively. The pairs
of top parts 20a
and 20b each define a triangular longitudinal recess 22 with the adjacent
inner surface of the top
wall 12. Similarly, the pairs of bottom parts 20d and 20e each define a
triangular longitudinal
recess 24 with the adjacent inner surface of the bottom wall 14. Hexagonal
longitudinal recesses
26 are defined between adjacent strengtheners.
[0039] As the board 10 is extruded, the top wall 12, the bottom 14, the side
walls 16 and 18 and
the strengtheners 20 all extend longitudinally along the entire length of the
board 10. The top
wall 12, the bottom wall 14, the side walls 16 and 18, and the strengtheners
20 are also integrally
formed.
[0040] As best shown in Fig. 3, the outer surfaces of the top and bottom walls
12 and 14 include
a number of longitudinal (anti-slip) ridges 28 formed thereon, to enhance
grip. The ridges 28 are
formed using through the use of a textured hot roller.
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[0041] Another way to describe the internal strengtheners 20 is that they
together form an
internal honeycomb strengthening structure defined by a row of longitudinally
extending cells
30. Each of the cells 30 is defined by a hexagon with its longest dimension
orientated normally
to the plane of the top and bottom walls 12 and 14.
[0042] Fig. 4 shows a second embodiment of scaffold board 10'. The board 10'
is similar to that
previously described and like reference numerals are sued to denote like
features. However, in
the board 10', the strengtheners 20 are slightly more widely spaced, resulting
in octagonal
recesses 26' therebetween.
[0043] The construction of the boards 10/10', particularly the strengtheners
and honeycomb
cells, provides them with superior flexural rigidity and the ability to meet
the Australian
Standards deflection test previously mentioned. The boards 10/10' are also
lighter than the
known boards previously discussed with the 2400 mm and 3600 mm length boards
weighing
10.8kg and 16.2kg respectively. This weight reduction provides several
advantages. Firstly, it
reduces the material required to produce the board, which saves production and
manufacturing
cost. Transport and manual handling costs are also reduced. Secondly, the
board 10 is light
enough to be able to be passed by hand between levels during erection or
dismantling of a
scaffold structure, as opposed to being carried between scaffold levels up
stairs and/or ladders,
which greatly reduces the time of both of those tasks.
[0044] The boards 10/10' also maintains the other advantages associated with
thermo plastic
construction over wooden/LVL boards including being: non-perishable; highly
resistant to UV;
self-extinguishing for flame; highly impact resistant; highly corrosion
resistant; not allowing for
transfer of radioactive particles; not contaminable by range of chemicals
including asbestos; not
allowing propagation of mould spores and bacteria; not allowing for
infestation by insects;
recyclable and environmental sustainable; and being colourable so as to be
easily distinguishable
for different uses.
[0045] Although the invention has been described with reference to preferred
embodiments, it
will be appreciated that the invention can be embodied in many other forms.
