Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
Scaffold unit
TECHNICAL FIELD
[0001] The present invention relates to a scaffold unit. More particularly,
the present
invention relates to a scaffold unit that can be moved from a lowered or
retracted configuration
to a raised or expanded configuration.
BACKGROUND ART
[0002] Scaffolding is widely used in the building and construction
industries. Conventional
scaffolding is erected from a number of separate components. Typically, a
number of posts or
rods are fastened together using brackets and bolts to form the scaffolding
framework, with
support boards or planks being placed on the scaffolding framework to form
walkways or work
platforms. Erection of conventional scaffolding requires that all of the
components be delivered
to a building site. A scaffolding crew will then erect the scaffold. This can
be time-consuming
and can add to the cost of construction.
[0003] Some effort has been made in the past to develop scaffold units in
which the work
platforms can be moved between a lowered position and a raised position. For
example, in US
patent 3877543, a scaffold unit is described which includes a horizontal
platform being mounted
to a plurality of vertical posts so as to be vertically movable up-and-down
along the vertical
posts. Rollers and drive rollers are pivotally mounted on an arm lever
provided on the platform.
A worm gear is coupled to the drive rollers to move the horizontal platform up
and down the
vertical posts by rotating the drive rollers. When a downward load is applied
to the platform, the
rollers and drive rollers are automatically pressed against the vertical posts
so that the platform is
prevented from slipping by the frictional force that is so generated. Products
known as "mast
climbers" have some similarity to the operating principle of the product
disclosed in US
3877543.
[0004] British patent number 191108619, which was filed in 1911, describes
a scaffold unit
in which support platforms can be raised and lowered to any desired level.
This unit includes a
plurality of support platforms that are connected together by a series of
articulated levers known
as "lazy tongs." The platform with the series of articulated levers rests on
an undercarriage
mounted two wheels so that it can be easily moved to a desired location. In
use, a shaft is turned
to drive the articulated levers to a raised configuration. In the raised
configuration, articulated
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levers are located below two comers of one end of each support platform.
Further articulated
levers are located below approximate midpoint of each support platform and the
support
platforms effectively cantilever outwardly from these articulated levers.
[0005] GB 759187 describes a mobile working platform in which the platform
is supported
by extensible lattice members that are raised by hydraulic or other means from
a mobile trolley
or truck. In this British patent, a single working platform is moved from a
lowered position to a
raised position by operating hydraulic rams to extend a pair of scissor arms
that are mounted on
either side of a chassis and the platform. A rack and pawl mechanism locks the
platform into
place.
[0006] GB 2022672 describes extensible scaffolding that uses a lazy tongs
arrangement.
Each of the lazy tongs arrangement comprises two pairs of levers. The levers
of each pair cross
each other and are pivotally connected together where they cross. A plurality
of transverse
structural members extend at right angles to the lengthwise dimension of the
lazy tongs
arrangement, with each transverse member having two guide elements mounted for
guided
movement along the transverse member. Each lever of the lazy tongs arrangement
has a guide
member attached at its ends. Two vertical scaffolding tubes extend in the same
plane as the lazy
tongs arrangement. To enable the lazy tongs arrangement to be extended, the
lowermost of the
transversely extending members carries a gearbox carrying journals for to
screw threaded shafts
extending parallel to the lowermost transverse member. Operation of this
enables the guide
members on the lowermost transverse member to move towards each other to
extend the lazy
tongs arrangements and raise the extensible scaffolding. As the lazy tongs
arrangements extend,
the respective transverse members are raised and slide upwardly along the
vertical members
located at either end of the transverse members. When the upper end of the
structure reaches the
required height, clamping bolts on the bottom transverse member are tightened
to fasten the ends
to the vertical scaffolding tubes. Then standing on the bottom member, the
operator can tighten
the bolts of the next member, and so forth, thereby allowing the operator to
climb the scaffold
and tighten the bolts. When in the extended position, the levers of the lazy
tongs arrangements
extend at an angle of between 20 and 30 to horizontal.
[0007] US 3820631 describes a platform lift device which is suitable for
raising workmen
and equipment to elevated positions which will enable them to perform
maintenance work on
aircraft. This patent describes existing lifting mechanisms that use
conventional scissor
mechanisms to raise and lower the work platforms. This patent states that such
conventional
scissor mechanisms possess at least three inherent disadvantages when employed
as a lifting
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mechanism. One disadvantage is the fact that the effective supported base area
defined by the
scissor ends decreases as the platform is raised, resulting in progressively
less stability at higher
elevations. The second disadvantage is the fact that the beams which comprise
such a scissor
linkage are subjected to bending loads and must therefore be relatively stiff
to support loads. A
third disadvantage is that the scissor linkages must be relatively long to
accomplish high lift
operations if done in one stage. Such long linkages necessitate a large and
cumbersome storage
pedestal chassis. In order to overcome these disadvantages, the lift platform
of this patent has an
elevating mechanism in which effectively the scissor lift arms of conventional
scissor lift
mechanisms are replaced with fluid power cylinders each having a ram or piston
mounted to
them so that struts that are pivotally connected to the chassis and the lift
platform extend relative
to the fluid power cylinders to thereby raise the work platforms. A mechanical
interlock is used
to ensure that the fluid power cylinders each extend at substantially
identical values of
incremental movement even if the platform is unequally loaded.
[0008] US 4088203 describes an adjustable scaffold comprising a platform on
base and an
adjustable interconnecting support structure. The adjustable interconnecting
support structure
comprises a number of sets of scissor mechanisms. Lifting means, typically
hydraulic cylinders
with lever brackets and support brackets pivotally attached thereto, are
positioned between sets
of scissor connectors, rather than within them. In other words, each cylinder
is attached to cross
members from different sets of scissor connectors. This is stated to provide a
sturdy and safe
lifting mechanism is capable of lifting substantial loads of personnel and
equipment. A pair of
scissor mechanisms are attached to the platform.
[0009] It will be clearly understood that, if a prior art publication is
referred to herein, this
reference does not constitute an admission that the publication forms part of
the common general
knowledge in the art in Australia or in any other country.
SUMMARY OF INVENTION
[0010] The present invention is directed to a scaffold unit which may at
least partially
overcome at least one of the abovementioned disadvantages or provide the
consumer with a
useful or commercial choice.
[0011] With the foregoing in view, the present invention in one form,
resides broadly in a
scaffold unit comprising at least two support platforms or two support frames,
at least one of the
support platforms or support frames being movable between a lowered position
and a raised
position, a plurality of scissor linkages linking one support platform or
support frame with a next
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support platform or support frame, each of the scissor linkages including a
plurality of legs, each
scissor linkage having a leg pivotally connected to or near a corner of one of
the support
platforms or support frames and a leg pivotally connected to or near a corner
of a next support
platform support frame, wherein a leg is pivotally connected at or near each
corner of a support
platform or support frame.
[0012] By providing a leg pivotally connected at or near each corner of a
support platform
or support frame, the support platform or support frame is supported at or
near each corner when
in the raised position. This provides a stronger, more stable and more secure
support to the
platform/frame.
[0013] In one embodiment, the scaffold unit further comprises a drive means
for raising and
lowering at least one of the support platforms or support frames between the
lowered position
and the raised position.
[0014] The drive means is suitably mounted to the scaffold unit. This
allows the drive means
to raise and lower the support platforms without requiring an externally
provided drive system.
[0015] In a second aspect, the present invention provides a scaffold unit
comprising at least
two support platforms or two support frames, at least one of the support
platforms or support
frames being movable between a lowered position and a raised position, a
plurality of legs
extending between one support platform or support frame and a next support
platform or support
frame, at least some of the legs having a pivotal connection to the support
platform or support
frame, the legs being movable during movement of the scaffold unit from the
lowered position to
the raised position and vice versa, the legs extending at an angle of less
then 10 to horizontal
when the scaffold unit is in the lowered position.
[0016] In one embodiment, at least some of the legs have a pivotal
connection at or near
corners of the support platform or support frame.
[0017] Suitably, the support platfoints or support frames that move during
raising or
lowering of the scaffold unit move in an essentially vertical direction during
raising or lowering.
By this, it is meant that the support platforms or support frames have a
negligible horizontal
component to their movement during raising and lowering of the scaffold unit.
[0018] The scaffold unit may further comprise a drive means for causing at
least some of the
legs to pivot about their pivotal connection at or near the corners of the
support platform or
support frame during raising and lowering of the scaffold unit.
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[0019] In some embodiments, the legs extend at an angle of less than 8 to
horizontal when
the scaffold unit is in the lowered position. In other embodiments, the legs
extend at an angle of
from 3 to 7 to the horizontal when the scaffold unit is on the lowered
position. In further
embodiments, the legs extend at an angle of from 4 to 6 , or even at an angle
of about 4 to 50
,
to the horizontal, when the scaffold unit is in the lowered position.
[0020] The scaffold unit may further comprise a further drive means to
facilitate initial
movement of a support platform or support frame from a lowered position. The
further drive
means may be selected from one or more of a column lifter, a hydraulic ram, an
air bag, a
pneumatic cylinder or a biasing means. In one embodiment, the further drive
means comprises a
biasing means that provides a biasing force to the legs when the scaffold unit
is in the lowered
position, the biasing force acting in a direction to assist raising the
scaffold unit. In this manner,
when the drive means is energised or actuated to raise the scaffold unit from
a lowered position,
the biasing means assists in raising the legs by applying an additional
biasing force to the legs
during the initial movement of the legs from the lowered position. This
facilitates the initial
movement of the legs from the lowered position (at which the legs are at an
almost horizontal
orientation) to the raised position. Further, a smaller or lower powered drive
means may be used
to raise the legs from the lowered position.
[0021] The biasing means may comprise one or more springs, or one or more
resilient
members, or one or more elastomeric or rubber members, or one or more
elastomeric or rubber
blocks, or one or more struts, such as one or more gas struts. The one or more
springs, one or
more resilient members, one more elastomeric or rubber members or one or more
elastomeric or
rubber blocks or one or more struts may extend in a vertical direction. In
other embodiments,
they may extend in a horizontal direction, or indeed they may extend at any
direction that can be
used to assist the initial movement from the lowered position.
[0022] In some embodiments, the further drive means contacts one support
frame or support
platform and another support frame or support platform when in the lowered
position, but the
further drive means only contacts the one support frame or support platform
when in the raised
position.
[0023] In some embodiments, the legs extend at an angle of greater than 80
, or greater than
85 , to the horizontal when the scaffold unit is in the raised position. In
some embodiments, the
legs may extend at an angle of about 86.5 to the horizontal when in the
raised position.
[0024] In the second aspect of the present invention, the links that are
pivotally connected to
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the support platforms or support frames may form part of scissor linkages.
[0025] In embodiments where the scaffold unit includes scissor linkages,
the scissor
linkages may comprise a first leg and a second leg, with the first leg being
pivotally connected to
a lower support platform or support frame at or near a corner of the lower
support platform or
support frame, the first leg and second leg being pivotally connected to each
other at an
approximate midpoint thereof, the second leg having a lower end that is
reciprocally movable
relative to the lower support platform or support frame, the first leg having
an upper end that is
reciprocally movable relative to an upper support platform or support frame,
the second leg
having an upper end that is pivotally connected to the upper support platform
or support frame at
or near a corner of the upper support platform or support frame.
[0026] In another embodiment, the scissor linkages may comprise a first leg
and a second
leg, with the first leg being pivotally connected to a lower support platform
or support frame at
or near a corner of the lower support platform or support frame, the first leg
and the second leg
being pivotally connected to each other at an approximate midpoint thereof,
the second leg
having a lower end that is reciprocally movable relative to the lower support
platform or support
frame, a third leg having an upper end that is pivotally connected to an upper
support platform or
support frame at or near a corner of the upper support platform or support
frame, a fourth leg
having an upper end that is reciprocally movable relative to the upper support
platform or
support frame, the third leg and the fourth leg being pivotally connected to
each other at an
approximate midpoint thereof, the third leg having a lower end that is
pivotally connected to an
upper end of the first leg and the fourth leg having a lower end that is
pivotally connected to an
upper end of the second leg.
[0027] The legs that are reciprocally movable relative to one of the
support platforms or
support frames may suitably be connected to one or more rollers that can move
along a track or
guide in or mounted to the support platform or support frame.
[0028] It will be understood that as the legs that are reciprocally movable
relative to one of
the support platforms or support frames are moved, those legs will also rotate
or pivot relative to
the support platform or support frame.
[0029] In some embodiments, the pivotal connection points of the respective
legs to one of
the platforms or support frames are located outwardly of the sliding ends of
the other legs of
each scissor linkage. This is a preferred embodiment. In another embodiment,
the sliding ends of
the respective scissor linkages are located outwardly of the pivotal
connection points of the other
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ends of each scissor linkage.
[0030] In embodiments where scissor linkages are used to link a lower
support platform or
support frame to an upper support platform or support frame, it is preferred
that the legs of the
scissor linkages extend at an angle of at least 80 , or at least 85 , to the
horizontal when the
scaffold unit is in the raised position.
[0031] In some embodiments, the scaffold unit is fitted with a drive means
to raise and
lower the unit. The drive means may comprise a drive motor, such as an
electric motor. The
electric motor may cause a drive bar or drive member to reciprocally move
relative to one of the
support platforms or support frames, movement of the drive bar or drive member
causing the
legs to move. The scaffold unit of the present invention may desirably have
the drive means
mounted on board.
[0032] In some embodiments, the scaffold unit may also be provided with a
braking means
that can be selectively actuated to prevent raising or lowering of the
scaffold unit and selectively
turned off or disengaged to allow raising or lowering of the scaffold unit. In
some embodiments,
the braking means may engage with one or more components of the drive means.
[0033] In other embodiments, the scaffold unit may be moved from a lowered
position to a
raised position by suspending the scaffold unit from a crane, releasing a
braking means or
releasing a locking means to allow the scaffold unit to expand under its own
weight and
subsequently engaging the braking means or locking means when the scaffold
unit is fully raised.
In a further alternative, the scaffold unit may be raised and lowered by
placing the scaffold unit
on the ground (or on a support base), releasing a braking means or releasing a
locking means,
raising the scaffold unit to the raised position by use of a crane and re-
engaging the braking
means or the locking means to hold the scaffold unit in the raised position.
Lowering may be
achieved by releasing the braking means or locking means and lowering the
crane to thereby
lower the scaffold unit under its own weight.
[0034] In one embodiment, the scaffold unit is provided with scissor
linkages and the drive
bar or drive member causes at least some of the legs that are mounted for
reciprocal movement
relative to one of the support platforms or support frames to move relative to
the support
platform or support frame.
[0035] In one embodiment, the drive motor causes a ball screw or a worm
gear to rotate, the
ball screw or worm gear extending through a nut fixedly mounted to a drive bar
or drive
member, wherein rotation of the ball screw or worm gear causes the drive bar
or drive member
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to move laterally outwardly or laterally inwardly. The drive motor may pass
drive through a gear
arrangement to cause rotation of the ball screw or worm gear.
[0036] In some embodiments, the scissor linkages may be moved and
repositioned inwardly
or outwardly relative to the support frame or support platform. In one
embodiment, the support
frame or support platform is provided with a plurality of spaced openings, one
leg of a scissor
linkage having an opening that can be brought into alignment with one of the
plurality of spaced
openings and a connecting pin passed through the aligned openings to thereby
pivotally connect
the one leg of the scissor linkage to the support platform or support frame.
It will be appreciated
that the other leg of the scissor linkage that is associated with that support
platform or support
frame can move along the support platform or support frame (for example, by
use of appropriate
rollers slides) and this allows easy repositioning of the scissor linkage. To
facilitate
repositioning, the drive means may be disconnected from the leg of the scissor
linkage that can
move along the support platform or support frame. This may be achieved by use
of an
appropriate clutch mechanism in the drive means, or use of an appropriate
quick disconnect
mechanism in the drive means.
[0037] Accordingly, in a third aspect, the present invention provides a
scaffold unit
comprising at least two support platforms or two support frames, at least one
of the support
platforms or support frames being movable between a lowered position and a
raised position, a
plurality of legs extending between one support platform or support frame and
a next support
platform or support frame, at least some of the legs having a pivotal
connection to the support
platform or support frame, the legs being movable during movement of the
scaffold unit from the
lowered position to the raised position and vice versa, wherein a position of
the pivotal
connection between a leg and the support platform or support frame can be
moved between a
plurality of positions. In this aspect, a plurality of scissor linkages may
extend between adjacent
support platforms or support frames.
[0038] In a fourth aspect, the present invention provides a scaffold unit
comprising at least
two support platforms or two support frames, at least one of the support
platforms or support
frames being movable between a lowered position and a raised position, at
least one of the
support platforms or support frames being provided with a support surface on
which a worker
can stand, the support surface including a horizontal extension movable
between a retracted
position and an extended position, the horizontal extension extending
outwardly from the support
platform or support frame when extended.
[0039] In some embodiments, the horizontal extension extends along a length
of the support
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platform or support frame. The horizontal extension may extend towards a
building located near
or adjacent to the scaffold unit. In this manner, the scaffold unit can be
spaced from the building
to minimise the possibility of the scaffold unit coming into contact with the
building and
damaging the building and the horizontal extension being extended to provide a
working
platform that has an end located very near or in contact with the building.
[0040] In some embodiments, the scaffold unit is provided with a protective
screen on one
side thereof. The protective screen may automatically extend when the scaffold
unit is raised.
The protective screen may be made from a mesh material or a shade cloth
material. The
protective screen may be a removable screen.
[0041] The scaffold unit may also be provided with one or more handrails.
In use when the
scaffold unit is in the raised position, the handrails may extend horizontally
along at least an
outer side of the scaffold unit. Additional handrails may be mounted to one or
more ends of the
scaffold unit if the scaffold unit itself comprises an end of a scaffolding
installation. The
handrails may be removably mounted to the scaffold unit.
[0042] In one embodiment, the uppermost support platform or support frame
may be
provided with one or more handrails or guardrails that are removably mounted
to a scaffold unit.
[0043] The support platform or support frame may have a support surface
that enables a
worker to stand or walk thereon.
[0044] The scaffold unit may also be provided with one or more stays
extending between
one support platform or support frame and a next support platform or support
frame. The one or
more stays may extend diagonally between the support platforms or support
frames. The one or
more stays may be extendable stays, such as telescoping stays. The one or more
stays may
provide additional resistance to movement of the support platforms or support
frames when in
the raised position. The one or more stays may include self locking means to
lock the stays into
an extended position when the scaffold unit is moved to the raised position.
[0045] The scaffold unit may be arranged such that a further scaffold unit
can be located on
top if access to a higher level is required. The scaffold unit may be provided
with locking means
for locking a first scaffold unit to a second scaffold unit positioned on top
of the first scaffold
unit. The locking means may comprise a locking bar extending through apertures
located in the
first scaffold unit and the second scaffold unit. The apertures may comprise
aligned apertures.
The locking bar may prevent relative horizontal movement and vertical movement
between the
first scaffold unit and the second scaffold unit.
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[0046] The scaffold unit may be provided with a base unit. The base unit
may comprise a
separate unit upon which the scaffold unit is supported and/or connected. In
one embodiment,
the base unit may comprise a frame. The frame may have one or more support
surfaces on which
the scaffold unit may be supported. The frame may include a plurality of legs
movable between a
retracted position and an outward position. The plurality of legs may comprise
adjustable legs.
The base unit allows for convenient setup of the scaffold unit. In particular,
the base unit may be
located at the desired position at which the scaffold unit is to be located.
The legs may be moved
to the outward position and the height of the legs adjusted to account for any
unevenness in the
ground and to set the base unit at the correct height. A scaffold unit may
then be positioned on
the base unit.
[0047] In other embodiments, the scaffold unit may be provided with
adjustable legs or
adjustable feet that extend below the lower support platform or support frame
in use.
[0048] In another embodiment, the present invention provides a scaffold
unit comprising at
least two support platforms or two support frames, at least one of the support
platforms or
support frames being movable between a lowered position and a raised position,
a plurality of
legs extending between one support platform or support frame and a next
support platform or
support frame, the legs comprising telescopically extendable and
telescopically retractable legs.
[0049] In one embodiment, the telescopic legs are raised and lowered by use
of hydraulic
cylinders, pneumatic cylinders, or electric motors. In one embodiment, the
telescopic legs are
raised and lowered by use of a driving means mounted on board the scaffold
unit.
[0050] In a further aspect, the present invention provides a scaffold unit
comprising at least
two support platforms or two support frames, at least one of the support
platforms or support
frames being movable between a lowered position and a raised position, a
plurality of scissor
linkages linking one support platform or support frame with a next support
platform or support
frame, each of the scissor linkages including a plurality of legs, wherein the
legs of the scissor
linkages extend at an angle of at least 80 to horizontal when the scaffold
unit is in the raised
position. In some embodiments, the scaffold unit has at least 4 sets of
scissor linkages linking
one support platform or support frame for next support platform or support
frame.
[0051] In all embodiments of the present invention, the scaffold unit may
be used in a
manner that does not require the scaffold unit to be attached to a building or
other structure. In
this regard, the scaffold unit can provide a sufficiently stable base to
enable the scaffold unit to
stand by itself next to a building.
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[0052] The scaffold unit of the present invention provides a scaffold unit
that can be
expanded from a lowered position in which the scaffold unit has a low profile,
compact
configuration to a raised position in which the scaffold unit enables access
to higher levels. In
some embodiments, the scaffold unit comprises three support platforms or
support frames, being
a lower support platform or support frame, an intermediate support platform or
support frame
and an upper support platform or support frame. In one embodiment, the drive
means may be
mounted to the intermediate support platform or support frame. In other
embodiments, the drive
means may be mounted to the lower support platform or support frame, or the
drive means may
be mounted to the upper support platform or support frame. In some
embodiments, more than
one support platform or support frame may be provided with drive means. The
drive means may
be effective to raise and lower all of the support platforms or support
frames.
[0053] The scaffold unit of the present invention may further be provided
with access stairs.
The access stairs may allow access between support platforms or support frames
on different
levels. The scaffold unit may be further provided with rubbish chutes. The
rubbish chutes may be
removable rubbish chutes. The rubbish chutes may be attached to the scaffold
unit when it is in
the raised position and removed from the scaffold unit before it is moved back
to the lowered
position. The scaffold unit may be further provided with loading bays.
[0054] The scaffold unit may be provided with a locking means to lock the
scaffold unit in
the lowered position. This can be useful for transportation and storage of the
scaffold unit.
[0055] Any of the features described herein can be combined in any
combination with any
one or more of the other features described herein within the scope of the
invention.
[0056] The reference to any prior art in this specification is not, and
should not be taken as
an acknowledgement or any form of suggestion that the prior art forms part of
the common
general knowledge.
BRIEF DESCRIPTION OF DRAWINGS
[0057] Various embodiments of the invention will be described with
reference to the
following drawings, in which:
[0058] Figure 1 shows a perspective view of a scaffold unit in accordance
with an
embodiment of the present invention in a lowered position;
[0059] Figure 2 shows a front view of the scaffold unit shown in figure 1;
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[0060] Figure 3 shows an end view of the scaffold unit shown in figure 1;
[0061] Figure 4 shows a top view of the scaffold unit shown in figure 1;
[0062] Figure 5 shows a perspective view of the scaffold unit shown in
figure 1 in a partly
raised state. In figure 5, the scaffold unit is approximately half extended;
[0063] Figure 6 shows a front view of the scaffold unit shown in figure 5;
[0064] Figure 7 shows an end view of the scaffold unit shown in figure 5;
[0065] Figure 8 shows a perspective view of the scaffold unit of figure 1
in the fully raised
position;
[0066] Figure 9 shows a front view of the scaffold unit shown in figure 8;
[0067] Figure 10 shows an end view of the scaffold unit shown in figure 8
[0068] Figure 11 shows a front view that is generally similar to that shown
in figure 6, but
with a protective screen included;
[0069] Figure 12 shows an end view of the scaffold unit shown in figure 11;
[0070] Figure 13 shows a view similar to that shown in figure 3, with
figure 13 indicating
section line K-K;
[0071] Figure 14 is a view that is similar to that shown in figure 2 but
showing the region of
detail H;
[0072] Figure 15 shows a plan view taken along section line K-K shown in
figure 13;
[0073] Figure 16 is a front view, partly in cross-section, of detail H
shown in figure 14;
[0074] Figure 17 is a front view, partly in cross-section, of detail J
shown in figure 11;
[0075] Figure 18 is a front view that is generally similar to that shown in
figure 9;
[0076] Figure 19 is an end view is generally similar to that shown in
figure 10 but with a
protective screen included;
[0077] Figure 20 is a detailed view of section A-A shown in figure 13;
[0078] Figure 21 is a detailed view of section D-D shown in figure 18;
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13
[0079] Figure 22 is a detailed view of region L shown in figure 11;
[0080] Figure 23 is a detailed view of region M shown in figure 18;
[0081] Figure 24 is an end view of part of the scaffold unit as shown in
figure 12, but in
large-scale than shown in figure 12;
[0082] Figure 25 is an enlarged view of detail T shown in figure 24;
[0083] Figure 26 is an enlarged view of detail P shown in figure 19;
[0084] Figure 27 shows an enlarged view of detail W shown in figure 19;
[0085] Figure 28 is a front view of the detail shown in figure 27;
[0086] Figure 29 is an end view of the lower two support frames of the
scaffold unit,
showing some internal details;
[0087] Figure 30 is an enlarged view of detail AC shown in figure 29;
[0088] Figure 31 is an enlarged view of detail AD shown in figure 18;
[0089] Figure 32 is a perspective view of a scaffold unit in the fully
raised position;
[0090] Figure 33 is an enlarged view of detail AH shown in figure 32
showing an exploded
view of the removable handrail;
[0091] Figure 34 is an end view of a support platform of the scaffold unit
in accordance with
the present invention;
[0092] Figures 35 to 37 show various views of a horizontal extending
support platform
being extended from the support deck of the support platform shown in figure
34 to reach a fully
extended position shown in figure 37;
[0093] Figure 38 shows an end view of a lower scaffold unit in a raised
position having an
upper scaffold unit in a lowered position being mounted thereto;
[0094] Figure 39 is a similar view to that shown in figure 38 with the
locking pin engaged to
lock both scaffold units together;
[0095] Figure 40 is a similar view to that shown in figure 39, but with the
handrails from the
upper support platform or support frame of the lower scaffold unit transferred
to the upper
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14
support frame of the upper scaffold unit;
[0096] Figure 41 shows the upper scaffold unit shown in figure 40 being
partly extended
partly raised;
[0097] Figure 42 shows an enlarged view of detail F shown in figure 38;
[0098] Figure 43 shows an enlarged view of detail H shown in figure 39;
[0099] Figure 44 shows an enlarged view of detail G shown in figure 41.
[00100] Figure 45 shows a perspective view of a "goalpost" is used as a
main connector
between a scissor and a deck for all locations except where the drive frame is
located;
[00101] Figure 46 shows the goalpost of figure 45 in a partially
disassembled state;
[00102] Figure 47 shows the goalpost of figure 45 apart and in line for
assembly
[00103] Figure 48 shows a perspective view of a base unit suitable for use
with a scaffold
unit in accordance with the present invention;
[00104] Figure 49 shows a plan view of the base unit shown in figure 48;
[00105] Figure 50 shows a side view of the base unit shown in figure 48;
[00106] Figure 51 shows an end view of the base unit shown in figure 48;
[00107] Figure 52 shows a perspective view of the base unit shown in figure
48 with one set
of legs extended;
[00108] Figure 53 shows a perspective view of the base unit shown in figure
48 with two sets
of legs extended;
[00109] Figure 54 shows a perspective view of the base unit shown in figure
48 with a
different set of legs extended;
[00110] Figure 55 shows a cross section of the leg assembly used on the
base unit shown in
figure 48;
[00111] Figure 56 shows a side view of another embodiment of the present
invention in a
lowered position. In figure 56, the scaffold unit is provided with a
vertically extending initial lift
device or further drive means;
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[00112] Figure 57 shows a side view of the scaffold unit shown in figure 56
in a partly raised
position;
[00113] Figure 58 shows a side view of the scaffold unit shown in figure 56
but with the
initial lift device removed from one end and the scissor linkage removed from
the other end, for
clarity;
[00114] Figure 59 shows the scaffold unit as shown in figure 58 in a partly
extended position;
[00115] Figures 60 to 63 show various views of a scaffold unit in
accordance with another
embodiment of the present invention in which the position of the scissor
linkages may be moved
inwardly and outwardly relative to the ends of the scaffold unit. Figures 60
to 63 show the
scissor linkages being in various positions;
[00116] Figures 64 and 65 show a scaffold unit in accordance with another
embodiment of
the present invention, with the scaffold unit having its fixed pivoting points
at an inner part of
the scissor linkages. Figure 64 shows a scaffold unit in a lowered position
and figure 65 shows
the scaffold unit in a partly raised position;
[00117] Figure 66 shows a side view of a scaffold unit in accordance with
another
embodiment of the present invention. In figure 66, adjacent support platforms
or support frames
are connected by the telescoping members;
[00118] Figure 67 shows the scaffold unit of figure 66 in a partly raised
position;
[00119] Figures 68 and 69 show a detailed view of an alternative biasing
means that is used
to assist in initial raising of the scaffold unit. In figure 68, the scaffold
unit is shown in the
retracted position and figure 69 the scaffold unit shown in a partly extended
position;
[00120] Figure 70 shows a view similar to that shown in figure 15, but with
an alternative
drive arrangement;
[00121] Figure 71 shows a perspective view of a scaffold unit in an
expanded position, with
the scaffold unit having the alternative biasing means shown in figure 68 and
69;
[00122] Figure 72 shows an expanded view of the connection between the legs
of the scissor
mechanism of the scaffold unit shown in figure 71; and
[00123] Figure 73 shows a view similar to that shown in figure 30 but of a
scaffold unit in
accordance with an alternative embodiment of the present invention. This
displays an alternate
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connection configuration of the handrail at the front and rear of the unit
DESCRIPTION OF EMBODIMENTS
[00124] Persons skilled in the art will appreciate that the drawings have
been provided for the
purposes of illustrating preferred embodiments of the present invention.
Therefore, it will be
understood that the present invention should not be considered to be limited
solely to the features
as shown in the attached drawings.
[00125] Figures 1 to 3 show various views of a scaffold unit in accordance
with an
embodiment of the present invention. The scaffold unit 10 shown in figures 1
to 3 is shown in
the lowered position. The scaffold unit 10 can be expanded from the position
shown in figures 1
to 3 to a raised position or an expanded position as shown in figures 8 to 10.
Figures 5 to 7 show
the scaffold unit 10 in a partly raised position. It will be appreciated that
the scaffold unit 10 can
also be moved (or retracted or lowered) from the raised position shown in
figures 8 to 10 back to
the lowered position shown in figures 1 to 3.
[00126] The scaffold unit 10 comprises three support frames 12, 14, 16.
Support frame 12 is
the lowest support frame. Support frame 16 is the upper support frame. Support
frame 14 is an
intermediate support frame. The support frames 12, 14, 16 each carry or
support a platform,
boards, planks or the like that enable a worker and/or equipment to be
supported or carried
thereon.
[00127] The scaffold unit 10 also includes guardrails 18, 20 that are
mounted to the upper
support frame 16. The guardrails 18, 20 will be described in more detail
hereunder.
[00128] Each of the support frames is connected to an immediately adjacent
or next support
frame by use of a plurality of linkage arrangements. Each linkage arrangement
includes legs that
are pivotally connected at or near corners of the support frame. In the
embodiment shown in the
attached drawings, the linkage arrangements comprise scissor linkages.
[00129] With reference to figures 5 and 6, a first linkage arrangement,
generally denoted at
21, comprises leg 22 that has a lower end 23 that is pivotally connected at or
near a comer 24 of
support frame 12. The linkage arrangement 21 further includes a leg 26 that
has a lower end 27
that is mounted to support frame 12 such that the lower end can move in a
reciprocal manner
relative to the support frame 12. For example, the lower end 27 of leg 26 may
be mounted to a
roller or slide that moves along a guide in support frame 12. Legs 22 and 26
are pivotally
connected to each other at pivot connection 28. Pivot connection 28 is located
at the approximate
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midpoint of legs 22 and 26.
[00130] The first linkage arrangement 21 further includes another leg 30
that is pivotally
connected at its lower end to the upper end of leg 26. In particular, legs 26
and 30 pivotally
connected at pivot connection 31. The upper end of leg 30 is mounted to
support frame 14 such
that the upper end of leg 30 can move into reciprocal manner relative to the
support frame 14.
The linkage arrangement 21 further includes another leg 32 that is pivotally
connected at its
upper end to support frame 14 at or near the corner 34 of support frame 14.
Corner 34 of support
frame 14 is positioned vertically above corner 24 of support frame 12. The
lower end of leg 32 is
pivotally connected at pivot connection 33 to the upper end of leg 21.
[00131] The lower support frame 12 and intermediate support frame are
connected by four
similar linkage arrangements, generally denoted at 21, 35, 36 and 37.
Similarly, intermediate
support frame 14 and upper support frame 16 are connected by four similar
linkage
arrangements.
[00132] As can be seen from figures 5 and 6, each of the linkage
arrangements 21, 35, 36, 37
has a leg that is pivotally connected at or near each corner of support frame
12 and at or near
each corner of support frame 14.
[00133] As the scaffold unit 10 is raised from the lowered position shown
in figures 1 to 3 to
the raised position shown in figures 8 to 10, the legs of each linkage
arrangement adopt a more
vertical configuration. In particular, in the lowered position shown in
figures 1 to 3, the legs of
the linkage arrangements may extend at an angle of less than 10 to the
horizontal, particularly
between four and 8 to the horizontal. Indeed, in the embodiment shown in the
attached
drawings, the legs of the linkage arrangements extend at approximately 4.6 to
the horizontal
when the scaffold unit 10 is in the lowered position. When the scaffold unit
10 is in the raised
position as shown in figures 8 to 10, the legs of the linkage arrangements
extend at an angle of
greater than 80 , more suitably at an angle greater than 85 , to the
horizontal. Indeed, in the
embodiment shown in the attached drawings, the legs of the linkage
arrangements extend at an
angle of 86.5 when the scaffold unit 10 is in the raised position. As the
legs of the linkage
arrangements are almost vertical when the scaffold unit 10 is in the raised
position, the linkage
arrangements can support significant weight. Further, the almost vertical
linkage arrangements
are located at or near each comer of the respective support platforms of the
scaffold unit 10. This
provides good stability to the scaffold unit 10 when it is in the raised
position.
[00134] Scaffold unit 10 may also be provided with diagonal stays 38, 40
that extend from
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one corner of support frame 12 to a diagonal corner of support frame 14. As
best shown in
figures 5 and 8, the diagonal stays are located near one side of the scaffold
unit 10. In this way, a
more open space is provided at the other side of the scaffold unit 10, in
order to provide a clear
or more open space for workmen to access a building from the scaffold unit 10.
The stays 38, 40
may comprise telescoping stays so that the stays can expand or lengthen as the
scaffold unit 10 is
raised and the stays can retract or shorten as a scaffold unit 10 is lowered.
The stays 38, 40 are
suitably pivotally mounted at their respective ends to the respective parts of
the lower support
frame 12 and intermediate support frame 14. Similar stays 42, 44 are provided
between the
intermediate support frame 14 and the upper support frame 16. The stays
provide additional
rigidity to the scaffold unit 10 when it is in the expanded position.
[00135] Figure 12 shows a scaffold unit 10 that is fitted with a protective
screen 46.
Protective screen 46 extends between the lower support frame 12 and the
intermediate support
frame 14. Similarly, a protective screen 48 extends between the intermediate
support frame 14
and the upper support frame 16. The protective screens 46, 48 may be made from
a mesh
material or a shade cloth type material or indeed from any material known to
be suitable for
forming protective screens for use in scaffolding. The protective screen may
be made from a
single piece of material, or it may be made from two pieces of material, or
indeed it may be
made from more than two pieces of material. Protective screens 46, 48 are
provided to minimise
the risk of workmen dropping tools or other objects from the support
platforms. They also
provide enhanced protection against falling for workers working on the support
platforms 12, 14.
It will be appreciated that the scaffold unit 10 shown in figure 12 is only
partly raised. As a
result, the protective screens 46, 48 shown in figure 12 have not been pulled
taut and they tend to
bag as a result. Further details of the protective screens will be provided
hereunder with
reference to figures 24 to 26.
[00136] Figure 15 shows a top view of the intermediate support frame 14,
but with the
support platform removed for greater clarity. The support frame 14 comprises a
plurality of
frame members. In particular, the support frame 14 includes end frame members
50, 52 and side
frame members 54, 56. The end frame members 50, 52 and the side frame members
54, 56 may
be in the form of beams, such as steel beams or aluminium beams or indeed
beams made from
any other material having comparable strength to aluminium or steel, including
C-section beams,
or they maybe in the form of hollow section steel beams, such as rectangular
hollow section
(RHS) beams. The side frame members 54, 56 may be C-section beams. The support
frame 14 is
also provided with comer castings 58, 60, 62, 64. The corner casting is may be
in the form of
ISO compliant comer castings for shipping containers or similar in order to
facilitate movement
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and transportation of the scaffold unit. The respective beams and corner
castings are welded
together to form a strong rectangular frame. Alternatively, the respective
beams and corner
castings may be bolted together, riveted together or joined using a
combination of bolts and
rivets. Other fasteners or fastening systems known to the person skilled in
the art may also be
used.
[00137] The frame includes intermediate frame members 66, 68. Intermediate
frame
members 66, 68 extend between the side frame members 54, 56 and are welded
thereto. The
intermediate frame members 66, 68 are used to form part of a housing for an
electric motor 70.
Electric motor 70 has an output shaft (not shown) that is connected to a
gearbox 72. The output
shaft from gearbox 72 connects to a T-gearbox 74. T-gearbox 74 is used to
rotate ball screws 76,
78. The distal ends of the ball screws 76, 78 are retained in bearing housings
80, 82 which allow
the ball screws 76, 78 to rotate whilst also holding the ends of the ball
screws in place. The
bearing housings 80, 82 mounted to the intermediate frame 14.
[00138] The intermediate frame 14 also houses drive bars 84, 86. Drive bars
may be in the
form of beams or RHS sections. Drive bar 84 has rollers 88, 90 attached
thereto. Similarly, drive
bar 86 has rollers 89, 91 attached thereto. The rollers 88, 90, 89, 91 are
mounted to roll in the
channel formed by the C-beam of side frame members 54, 56. The reciprocally
movable ends of
the legs 30, 92 are also mounted to drive bar 84 (leg 92 is part of the
linkage extending between
the intermediate support frame 14 and the upper support frame 16. Leg 92 is
also shown in figure
6). These legs are also mounted to another roller 94. Roller 94 also rolls in
a guide channel
formed by the C-beam of side frame member 56. The other reciprocally movable
legs of the
linkage arrangements are also mounted to the respective drive bars 84, 86 in a
similar manner.
[00139] The drive bars 84, 86 include an aperture through which the
respective ball screws
76, 78 can pass. Ball screw nuts 96, 98 are affixed to the drive bars such
that the ball screw 76,
78 engage with the ball screw nuts 96, 98. In this manner, when the ball
screws 76, 78 are caused
to rotate by operation of the electric motor 70, interaction between the ball
screws and their
respective ball screw nuts causes the drive bars 84, 86 to move along the ball
screws 76, 78.
Depending upon the operation of the electric motor, this causes the drive bars
84, 86 to move
either outwardly or inwardly, thereby causing the scaffold unit 10 to either
raise or lower.
[00140] The legs 32, 93 that are pivotally connected at or near the corner
34 of the
intermediate support frame 14 are also shown in figure 14. As can be seen, the
outer ends of legs
32, 93 are mounted about a pivot pin 99 which, in turn, is connected to a
connecting bar 100.
Connecting bar 100 also carries a pivot pin 101 that is used to connect the
similar pivoted legs
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(not numbered in figure 14 for clarity purposes) on the other side of the
support frame 14. Pivot
pins 99, 101 are pivotally mounted to the respective side frame members 54,
56.
[00141] The arrangement shown in figure 15 advantageously allows a single
drive motor to
raise or lower both intermediate support platform 14 and upper support
platform 16. In
particular, if the scaffold unit 10 is in its lowered position (as shown in
figure 1) and the drive
motor 70 is energised to cause the drive bars 84, 86 to move outwardly, this
causes the
reciprocally movable ends of legs 32 and 92 (and the other similarly
reciprocally movable ends
of the legs of the other linkage arrangements) to move outwardly. As a result,
the linkage
arrangements between the intermediate support frame 14 and lower frame 12
start to extend.
Similarly, and at the same time, the linkage arrangements between the
intermediate support
frame 14 and the upper support frame 16 are also caused to extend. This
results in the spacing
between the support frames 12, 14 and 16 increasing as the scaffold unit is
raised. This enables a
compact and yet robust drive mechanism to be used to raise and lower the
scaffold unit 10.
[00142] It will also be appreciated that the drive means may be arranged on
the lower support
platform or support frame or on the upper support platform or support frame.
Indeed, drive
means may be provided on two or more of the support platforms or support
frames.
[00143] Although use of an electric motor 70 is preferred in order to raise
and lower the
scaffold unit, the electric motor may be replaced by any other known apparatus
to cause rotation
of the shaft. For example, the electric motor may be replaced by a hand
operated wheel, by a nut
that can be caused to rotate by use of an appropriate rattle gun or electric
drill having a suitable
socket connection, or indeed by any other known system for causing rotation of
a shaft. In
embodiments where an electric motor is used, the electric motor may be powered
by an external
electricity supply or it may be powered by an on-board battery supply.
[00144] In some embodiments, the scaffold unit may also be provided with a
braking means
that can be selectively actuated to prevent raising or lowering of the
scaffold unit and selectively
turned off to allow raising or lowering of the scaffold unit. The braking
means may engage with
one or more components of the drive means.
[00145] It will also be understood that there may be a number of
alternative drive systems or
drive arrangements that may be used in the scaffold unit of the present
invention. Indeed, the
present invention encompasses any drive system or drive arrangement or drive
means that allows
the scaffold unit to be raised and lowered.
[00146] Figure 16 shows an enlarged cross sectional view of detail H shown
in figure 14. In
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figure 16, the scaffold unit 10 is in the lowered position. The reciprocally
movable end of leg 92
that is mounted to roller 94 can clearly be seen. Similarly, the reciprocally
movable end of leg 26
can be clearly seen. These are mounted to roller 110 that is adapted to move
along a guide
formed in a channel in a side of frame member of lower support frame 12. Leg
32 can also be
seen. Similarly, the reciprocal movable end of leg 108 can be seen. This leg
is mounted to roller
112. Roller 112 is mounted so that it can move along a channel or guide formed
in a side frame
member of upper support frame 16. The other linkage arrangements are similarly
arranged.
[00147] In order to assist in moving the legs of the linkage arrangements
from the lowered
position in which the legs extend in an almost horizontal direction (in the
embodiment shown in
figure 16, the legs extend at an angle of 4.6 to horizontal), biasing means
114, 115, 116, 117 are
provided. Biasing means 114, 116 are shown in figure 16, with all biasing
means 114, 115, 116
and 117 being shown in figure 15. The biasing means may be in the form of
blocks of rubber or
elastomer. In other embodiments, the biasing means may comprise one or more
springs. When
the scaffold unit 10 is in the lowered position as shown in figure 16, the
drive bars 84, 86 contact
and compress the biasing means 114, 115, 116, 117. When it is desired to raise
the scaffold unit
10, the drive motor 70 is operated and this applies a force to the drive bars
84, 86. As the drive
bars 84, 86 are also compressing the respective biasing means at this stage,
the biasing means
also provide an additional force to assist in pushing outwardly on the drive
bars 84, 86. Thus, the
initial pushing force provided to the drive bars by the drive motor is
enhanced by the reactive
force caused by compression of the biasing means by the drive bars. Thus, at
the very beginning
of outer travel of the drive bars 84, 86, a force that is larger than the
force provided by the drive
motor alone is applied. This assists in moving the legs from their almost
horizontal
configurations. As the drive bars move outwardly, the legs move to a more
vertical orientation. It
has been found that once the drive bars have been moved sufficiently outwardly
to clear the
biasing means, the legs have a sufficiently vertical orientation to allow the
power of the drive
motor to continue raising the legs. Independent engineers who provided a
confidential review of
the drive system of the present invention commented that the legs would not be
able to be lifted
by the drive motor if the closed angle was less then 10.5 . The present
inventors have shown that
this is not the case.
[00148] Figure 17 shows an enlarged view of detail J shown in figure 11.
This is a view that
is similar to the view shown in figure 16, but with the scaffold unit 10 being
raised to about a
halfway position. As can be seen from figure 17, the drive bars 84, 86 are now
clear of the
biasing blocks 114, 116. The more vertical position of legs 30 and 92 can also
be seen.
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[00149] Figure 20 shows an enlarged view taken along section A-A and
section B-B of figure
12 and figure 21 shows an enlarged view taken along section C-C and section D-
D of figure 18.
These figures show one embodiment by which the guardrail 18 may be mounted to
the upper
support frame 16. The guardrail 18 includes a generally vertical extending
post 120. A button
122 is mounted to an upper part of the vertical post 120. Button 122 operates
a cable 124 that
extends through vertical post 120. Cable 124 passes over fixed cable guides
126, 128, 130. The
lower end of cable 124 is connected to a movable tongue 132. The movable
tongue 132 is
housed in a housing 134 at lower end of the post 120. Housing 134 may comprise
the vertically
extending lower part 222 of the post 120 (see figure 38). Housing 134 is
received in a sleeve or
bracket 136 that is welded to side frame member 138 of the upper support frame
16. The sleeve
or bracket 136 has an open bottom. The low section of housing 134 forms a stop
member 140.
[00150] In order to mount the guardrail 18 to the upper frame member 16,
the button 122 is
depressed, which causes tongue 132 to be retracted. This is shown in figure
20. The housing 134
is then inserted into the sleeve or bracket 136 until tongue 132 is positioned
below the lower end
of sleeve or bracket 136. The button 122 may then be released, which causes
the tongue 132 to
be released and to extend outwardly, as shown in figure 21. This results in
the tongue 132
retaining the housing 134 (and the vertical post and also the guardrail 18) in
the sleeve or bracket
136. In order to remove the guardrail 18 from the upper frame member 16, the
button is pressed
again, which retracts the tongue, thereby enabling the guardrail 18 to be
lifted out of the sleeve
136. It will be appreciated that the tongue may be biased to the extended
position by use of a
biasing means 133. Biasing means 133 may comprise a rubber block or a spring.
[00151] It will also be appreciated that the guardrail 18 may be provided
with a number of
vertical posts 120. A plurality of the vertical posts may be provided with the
locking means as
described above. It will also be understood that the guardrail may be
connected to the upper
platform by a number of other mechanisms or connections. For example, the
guardrail 18 may be
simply bolted to the upper platform. Alternatively, the guardrail 18 may be
received in one or
more openings or pockets that present in the upper surface of the upper
platform or support
frame or that are attached to the side of the upper platform or support frame.
[00152] Figures 22 and 23 show operation of the stays. Stay 38 comprises a
telescopically
extendable stay having a hollow portion 140 that can telescopically receive
rod 142. Rod 142 is
pivotally connected at its upper end 144 to intermediate support frame 14.
Similarly, although
not shown, the lower end of hollow portion 140 is pivotally connected to the
lower support frame
12. As the scaffold unit 10 continues to be raised from the part raised
position shown in figure 22
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to the fully raised position shown in figure 23, the rod 142 continues to
extend outwardly from
hollow portion 140 until the scaffold unit 10 reaches the fully raised
position. The stay 38 may
be provided with a self locking mechanism such that when the stay 38 is fully
extended, the rod
142 automatically locks in position relative to the hollow portion 140. The
stays result in
increasing the rigidity of the scaffold unit 10 when in the raised position.
[00153] Figures 24 to 26 show various views of one way of ensuring that the
protective
screen 46 can be guided and retained in position. In figure 24, the scaffold
unit 10 is partly
raised, as shown in figure 6. A hand rail 150 is mounted at the pivot points
where the upper and
lower legs of the linkage 35 are pivotally connected to each other. The
protective screen 46 may
be in the form of a fabric or mesh (such as a shade cloth type mesh) and it is
located behind the
handrail 150. A guide 151 guides the mesh inwardly. This acts to retain the
middle part of the
protective screen 46 in position. As the scaffold unit 10 is raised, the mesh
remains behind the
handrail 150 but is stretched toward, as shown in figure 26.
[00154] In some embodiments, the lower end intermediate support frames 12,
14 may be
provided with an incorporated mid-rail and toeboard. Figures 27 and 28 show
these features.
Figures 27 and 28 include an enlargement of detail W shown in figure 19. The
mid-rail 152 and
toeboard 154 can be seen in figure 28. The mid-rail 152 is supported by a
number of generally
vertical posts, one of which is shown at 156. The mid-rail and toeboard may be
removable from
the scaffold unit.
[00155] Figure 29 shows an enlarged view of detail AB shown in figure 13.
This shows the
lower support platform 12 and the intermediate support platform 14 in the
lowered position. It
will be appreciated that upper support platform 16, which can be partially
seen in figure 29, will
be directly above intermediate support platform 14. The support platform 12
supports a deck
160. Similarly, support platform 14 supports a deck 162. The decks provide a
support surface or
walking surface on which workers and equipment can stand or walk. The linkage
arrangements
35, 37 fold up and partly fit into the space caused by the deck 160 acting as
a spacer between the
lower support frame 12 and intermediate support frame 14. Springs 164, 166
push against the
lower support frame 12 in order to operate and positively engage the locking
mechanism, as will
be described in more detail with reference to figures 42 and 44. Handrail 150
also fits into this
space, as can be more clearly seen in figure 30. Alternatively, one or more
locking bars may be
used to lock the scaffold unit in the retracted position for transport and
storage.
[00156] Figures 32 and 33 show expanded detail of how the legs of the
scissor linkages are
pivoted together and how the handrail is mounted thereto. With reference to
figures 32 and 33,
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lower leg 170 is pivotally connected to upper leg 172. Similarly, lower leg
174 is pivotally
connected to upper leg 176. The lower are pivotally connected to each other at
pivot point 178.
Similarly, upper legs 172, 176 pivotally connected together at pivot point
180.
[00157] The legs 170, 172 are pivotally connected together by forming
aligned holes in those
links. A pin 182 extends through the holes and a locking pin 184 is used to
retain the pin 182 in
position. It will be understood that the legs 170, 172 can pivot around pivot
pin 182. Bushings,
such as nylon bushings, bronze bushings or bushing are made from any other
suitable bushing
material 186, may be inserted in the openings in the legs in order to minimise
friction and noise
during pivoting. The handrail 150 may be positioned inside a bracket 188 that
can be pivotally
connected to pivot pin 182. In this regard, an opening 190 may be formed in
the head of pivot
pin 182 and an appropriate fastening pin (not shown) may be used to connect
the handrail
bracket 188 to the pivot pin 182. The handrail 150 may be slidable within the
bracket 188 to
enable the brackets to slide along the handrail whilst the scaffold unit is
being raised or lowered.
In other embodiments, the handrail 150 is locked into position. Bracket 188
may swing open to
enable easy installation and removal of handrail 150.
[00158] Figures 34 to 37 show operation of a horizontally extendable deck.
In particular,
lower support frame 12 is provided with a deck 160. Deck 160 may have a
horizontally
extendable portion. As shown in figure 35, the horizontally extending portion
200 can extend
sideways from the deck 160. Figure 36 shows the extending portion 200 of deck
160 being
further extended, with figure 37 showing the extending deck 200 being at its
maximum
horizontal extension. As can be seen, use of a horizontal deck having a
portion that is both
extendable and retractable can allow for the deck to extend horizontally to
fill in any gap or
space between the scaffold unit 10 and a building that is adjacent to the
raised scaffold unit 10.
In this manner, the scaffold unit 10 can be spaced from the building at a
desired minimum
distance so that undesired contact between the scaffold unit 10 and the
building is avoided. This
helps to avoid causing damage to the building, particularly in instances where
the scaffold unit
is being used adjacent to a completed building (for example, for maintenance
purposes or
cleaning purposes).
[00159] Although not shown in figures 34 to 37, the deck 160 will have a
hollow having a
side opening through which the extendable portion 200 of the deck can be
extended and
retracted. The extendable portion 200 of the deck may be extended and
retracted using a drive
means, such as a drive motor. Alternatively, the extendable portion 200 of the
deck may be
manually moved inwardly and outwardly. One or more locking arrangements, such
as locking
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pins that fit into apertures in the deck 160 and the extendable portion 200 of
the deck, may be
used to lock the extendable portion of the deck in position.
[00160] The other support platforms may also be provided with decks that
can extend and
retract horizontally.
[00161] Figures 38 to 41 show a guard rail 18, 20 being moved from a lower
scaffold unit 10
to an upper scaffold unit 210. In figure 38, the lower scaffold unit 10 is in
its fully raised
position. If it is desired to obtain access to even higher areas, a second
scaffold unit 210 that is
essentially identical to scaffold unit 10 is mounted to the upper support
frame 16 of lower
scaffold unit 10. As can be seen from figure 38, the guard rail 18 has a
vertical support post 120.
The lower end of the vertical support post 120 extends inwardly at 220 and
then extends
vertically downwardly again at the very end, as shown at 222. In this way, a
major part of the
length of support post 120 is spaced outwardly from the upper support frame
16. This provides
sufficient space to enable the upper scaffold unit 210 to be positioned on top
of the upper support
frame 16 of the lower scaffold unit 10 without first having to remove the
guardrails 18 and 20.
[00162] Once the upper scaffold unit 210 has been placed on the lower
scaffold unit 10, the
scaffold units 10, 210 may be locked together (as will be described with
reference to figures 42
to 44). The guardrails 18, 20 may then be unlocked (as described with
reference to figures 20 and
21) and repositioned to be mounted into the appropriate support brackets
mounted to the sides of
the upper support frame of upper scaffold unit 210. This is shown in figure
40. The upper
scaffold unit 210 may then be raised, as shown in figure 41. In figure 41, the
upper scaffold unit
210 is partly raised.
[00163] In order to lock the upper scaffold unit 210 to the lower scaffold
unit 10, an opening
230 that leads into a passage 232 that is formed in one of the members of
upper support frame 16
or in the corner castings of the upper support frame 16. The upper scaffold
unit 210 includes a
lower support frame 234, an intermediate support frame 236 and an upper
support frame 238.
Each of the support frames includes member corner castings that have passages
240, 242 and
244. Passage 244 has an upper opening 246 of decreased diameter or size.
Similarly, passage 244
has an upper opening 248 of decreased diameter or size. A biasing spring 250
is mounted in
passage 240. Another biasing spring 252 is mounted in passage 242. A locking
bar 254 having a
top cap 256 and a bottom cap 258 is positioned so that it extends through
aligned passages 240,
242, 244. It will be appreciated that the upper scaffold unit 210 shown in
figure 42 is in the
lowered position.
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26
[00164] Once the upper scaffold unit 210 is positioned on the lower
scaffold unit 10, as
shown in figure 42, the locking bar 254 is actuated by rotating by 90 . The
top cap 256 and the
bottom cap 258 have a narrow side and a longer side. Rotating the bar by 90
brings the narrow
side into alignment with the narrow openings 230, 231 and 246. This enables
the locking bar 254
to move downwardly such that bottom cap 258 passes through aligned narrow
openings 230,
231, as shown in figure 43. This acts to lock the lower scaffold unit 10 to
the upper scaffold unit
210. It will be appreciated that similar locking mechanisms are provided on
each corner of the
scaffold units. The upper scaffold unit may then be extended/raised, as shown
in figure 44. In
some embodiments, the lower end of the locking bar 254 may engage at its lower
end with the
lower scaffold unit. For example, the lower end of the locking bar 254 may be
restricted from
moving further downwardly once it is moved into a locking position. In this
embodiment, it may
be possible to omit the springs shown in figures 42 to 44 and in figure 29.
[00165] Figures 45 to 47 show the connection of the legs of the scissor
linkages that are
pivotally connected at or near the corners of the support frames. For example,
in figure 45, leg
22 (refer to figure 6) and the corresponding leg 270 on linkage 36 are
interconnected by a rod
272. Rod 272 is welded to respective scissor arms 22, 270. Rod 272 is a hollow
rod that can
receive an insert 274. This is shown in figure 46. Insert 274 comprises a
hollow locking insert
276 that is fitted with a threaded insert 278. Bushes 280, such as nylon
bushes, are fitted to an
opening 284 in scissor leg 22. The locking insert with fitted threaded insert
278 is inserted into
the hollow end of rod 272 prior to welding the rod to 72 to the scissor arms
22, 270.. An
appropriate threaded locking pin or locking bolt, such as pivot pin 99 or 101
(see figure 15) is
then passed through the opening 284 and bushes 280, 282 to thereby pivotally
connect the
scissor arms 22, 270 to the lower frame members.
[00166] Figures 48 to 51 show various views of a base unit 300 in
accordance with the
present invention. The base unit 300 comprises a frame made up of frame
members 302, 304,
306 and 308 that are welded or bolted together to form a generally rectangular
frame. Support
surfaces 310, 312, 314 are welded to the frame at locations at or near the
comers of the frame.
The frame may also be provided with comer castings, one of which is numbered
at 318, to assist
in transport of the frame.
[00167] Each of the support surfaces 310, 312, 314, 316 is provided with an
opening 350.
Opening 350 can receive respective locking bars 254 (refer to figures 42 to
44) which allow the
scaffold unit placed on the base unit 300 to be securely fastened to the base
unit in a manner that
is similar to that as described with reference to figures 42 to 44.
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[00168] The frame is also provided with four leg assemblies, with each leg
assembly being
located near a corner of the frame. One leg assembly is numbered at 320 in
figure 49. The leg
assembly 320 includes a first leg 322 and a second leg 324. Both legs 322, 324
can pivot about
90 from the retracted position shown in figures 48 to 51 to an extended
position in which the
legs extend generally vertically. Leg 322 is fitted with a foot 326.
Similarly, leg 324 is fitted with
a foot 328. The other leg assemblies in the other corners of the frame are
similar.
[00169] Figure 55 shows more detail of the leg assembly 320. In figure 55,
the leg 322 has
been pivoted to the extended position in which the leg 322 extends in a
generally vertical
direction. Leg 324 is still in its retracted position in which it is
positioned in a generally
horizontal orientation.
[00170] As can be seen from figure 55, leg 326 comprises an outer tube 330
having a nut 332
welded position therein. An inner threaded rod 334 is mounted in a bearing
block 336. The inner
threaded rod 334 can rotate relative to the outer tube 330. This causes the
outer tube 330 to move
along the inner threaded rod 334 to thereby adjust the length of the leg 322.
[00171] Returning to figure 49, leg 322 is pivotally mounted in bracket
340. Similarly, leg
324 is pivotally mounted in bracket 342. Leg 324 is somewhat shorter than leg
322.
[00172] Figure 52 shows the longer legs 322 mounted at the end of the base
unit near frame
member 308 being extended, whilst the legs at the other end of the base unit
near frame member
304 remained retracted. In this configuration, the end of the base unit at 304
can rest on the
ground whilst the feet of the long legs 322 at the end of the base unit near
308 can also rest on
the ground. This allows the base unit to be positioned horizontally on sloping
ground having a
reasonable slope.
[00173] Figure 53 shows the longer legs 322 at end 308 being extended and
the shorter legs
324 at end 304 also being extended. This allows the base unit to be
horizontally set on gently
sloping ground whilst also allowing the height of the base unit to be set at a
desired level.
[00174] Figure 54 shows an embodiment in which legs 322 mounted near frame
member 304
have been extended. This provides for the shorter legs at that end of the base
unit to be extended
whilst the other legs at the other end of the base unit remain retracted. This
allows the other end
of the base unit to rest on the ground whilst the short extended legs at the
end near frame
member 304 rest on the ground. In this configuration, the base unit can be
securely positioned on
ground having a gentle slope.
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28
[00175] It will be appreciated that the operator will select the legs to be
extended (the shorter
legs or the longer legs) and then adjust those legs to the desired height to
ensure that the top of
the base unit 300 is level/horizontal and that it is at the correct height
such that the extended
scaffold unit placed on top will have its support decks at the required
height, for example at the
required height necessary to align the support decks with floor levels of a
building. Figures 56 to
59 show various views of a scaffold unit in accordance with another embodiment
of the present
invention. Referring initially to figures 56 and 57, the scaffold unit 400
shown in these drawings
includes a first support platform or support frame 402 and a second adjacent
support platform
404. It will be appreciated that further support platforms or support frames
may be mounted
above frame 404 or below frame 402. Scissor linkages 406, 408, which may be
essentially
identical to the scissor linkages as described with reference to figures 1 to
10, connect the
support frame 402 to the support frame 404. In some embodiments, there will be
four scissor
linkages connecting each support frame to an adjacent support frame. A drive
mechanism similar
to that shown in figure 15 may be used to raise and lower the scissor linkages
406, 408.
[00176] In order to assist with the initial movement of the scaffold unit
from the lowered
position, further drive means in the form of initial lift devices 410, 412 are
positioned between
frame 402 and frame 404. The initial lift devices can extend in an essentially
vertical direction.
For example, as shown in figure 56, when in the lowered position, the initial
lift devices 410, 412
have a short vertical extent. When extended, as shown in figure 5'7, the
initial lift devices 410,
412 have a much larger vertical extent. In order to move the scaffold unit 400
from the lowered
position to the raised position, the initial lift devices 410, 412 may be
actuated to cause the
support frame 404 to be raised away from the support frame 402. This, of
course, also causes
vertical extension of the scissor linkages 406, 408. The drive means to drive
the scissor linkages
may be actuated or may become more effective at raising the scissor linkages
once the legs of the
scissor linkages become more vertical, for example, once those legs are
positioned at an angle of
greater than 10 to the horizontal, to continue raising of the scaffold unit.
[00177] The legs of the scissor linkages may extend at an angle of less
than 10 to the
horizontal when the scaffold unit 400 is in the lowered position. The initial
lift devices 410, 412
may replace the biasing means 114, 115, 116, 117 shown in the drive means of
figure 15.
Alternatively, the initial lift devices 410, 412 may assist the biasing means
shown in figure 15
with the initial raising of the support frame.
[00178] In some embodiments, the support frame 404 may move away from the top
of the
initial lift devices 410, 412 as the support frame 404 moves to the raised
position. In this regard,
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29
the initial lift devices 410, 412 may have a maximum vertical extension that
is less than the
distance between the support frames 402, 404 in the fully raised position. It
will be appreciated
that the lower end of the initial lift devices 410, 412 may be connected to
the support frame 402
but the support frame 404 might only rest on the initial lift devices 410, 412
when in the lowered
position.
[00179] It will also be appreciated that figures 57 and 59 show the
scaffold unit 400 in a
partly raised position. When in the fully raised position, the legs of the
scissor linkages 406, 408,
may extend at an angle of greater than 800 to horizontal.
[00180] Figures 60 to 63 show a scaffold unit 420 in accordance with
another embodiment of
the present invention. The scaffold unit 420 comprises a support frame 422 and
an adjacent
support frame 424. Although not shown in figures 60 to 63, it will be
appreciated that further
support frames may be included in the scaffold unit 420. In one embodiment,
the scaffold 420
may include 3 support frames. The support frame 422 includes a side beam that
has a plurality of
spaced openings, some of which are numbered at 426, 428, 430, 432, 434.
[00181] Scissor linkages 436, 438 connect support frame 422 to support
frame 424. The
scissor linkages 436, 438 may be similar to the scissor linkages as described
with reference to the
embodiment shown in figures 1 to 10. In particular, scissor linkage 436
includes a leg 440 that is
pivotally connected at its lower end to the support frame 422. Scissor linkage
436 also includes a
leg 442 that is pivotally connected at its upper end to support frame 424.
Scissor linkage 436 has
a leg 444 that has a lower end that is movable inwardly and outwardly along a
track or guide of
the support frame 422. Scissor linkage 436 also includes a leg 446 that has an
upper end that is
movable inwardly and outwardly along a track or guide of the support frame
424.
[00182] In the embodiment shown in figures 60 to 63, the location of the
scissor linkages
436, 438 are adjustable and can be moved to a desired location, depending on
the site
requirements. In order to connect the scissor linkage 436 to support platforms
422, 424, openings
in the respective ends of legs 440, 442 are aligned with respective openings
formed in the side
beams of support frames 422, 424. Pivot pins 448, 450 are then inserted
through the aligned
openings to thereby pivotally connect the respective ends of legs 440, 442 to
the respective
support frames 422, 424. The inwardly/outwardly movable ends of legs 444, 446
can slide along
their respective guides or tracks during repositioning of the scissor linkages
inwardly or
outwardly. The drive mechanism that drives the scissor linkages to raise and
lower the scissor
linkages may be disconnected during this repositioning process.
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[00183] In figure 60, the scissor linkage 436 is shown to be pivotally
connected to opening
430. Scissor linkage 438 is similarly positioned at the other end of the
scaffold unit 420. In figure
61, the scissor linkage 436 is pivotally connected to opening 428. Scissor
linkage 438 is similarly
positioned at the other end of the scaffold unit 420. In figure 62, the
scissor linkage 436 is
pivotally connected to opening 426. Scissor linkage 438 is positioned such
that it is pivotally
connected at opening 452. As can be seen from figure 62, scissor linkage 436
is positioned at an
outer end of the scaffold unit 420 whereas scissor linkage 438 is positioned
inwardly from an
outer end of the scaffold unit 420. In figure 63, scissor linkage 436 is
pivotally connected to
opening 430 and scissor linkage 438 is pivotally connected to opening 452.
Thus, the position of
the respective scissor linkages can be moved and located in accordance with
specific site
requirements for any particular job.
[00184] Figures 64 and 65 show side views of a scaffold unit 470 in
accordance with another
embodiment of the present invention. The scaffold unit 470 includes support
frame 472 and
support frame 474. Scissor linkages, 476, 478 connect support frames 472, 474.
In contrast to the
embodiment shown in figures 1 to 10, the scissor linkages are not located
directly under corners
of the support platforms. Rather, they are mounted slightly inboard from the
comers. Further, the
fixed pivot points of the scissor linkages are located at the inner part of
the scissor linkages. For
example, the fixed pivot points of scissor linkage 476 are shown at 480, 482
and the fixed pivot
connections of scissor linkage 478 are shown at 484, 486. Appropriate changes
to the drive
mechanism shown in figure 15 can be made so that the inwardly and outwardly
movable ends of
the scissor linkages are raised by moving those ends inwardly and lowered by
moving those ends
outwardly.
[00185] Figures 66 and 67 show a scaffold unit 500 having support frames
502, 504. Vertical
telescoping members 506, 508 extend between the support frames 502, 504. The
vertical
telescoping members 506, 508 are suitably connected at either end to the
respective support
frames 502, 504. The vertical telescoping members 506, 508 may comprise
hydraulic cylinders
or hydraulic rams, pneumatic cylinders or pneumatic rams, or column lifters.
In this
embodiment, motive power, such as a source of pressurised hydraulic fluid or
pressurised
pneumatic fluid, or an electric actuator, may be mounted on the scaffold unit
500. Alternatively,
the scaffold unit 500 may be connected to external sources of pressurised
fluid or electrical
power. The vertical telescoping members 506, 508 may be operated such that
they extend to
thereby raise the scaffold unit 500 and retract to thereby lower the scaffold
unit 500.
[00186] Figures 68 and 69 show side views of one end of a scaffolding unit
in accordance
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31
with another embodiment of the present invention. The embodiment shown in
figure 68 and 69
includes three support platforms 602, 604, 606 that are interconnected by
scissor linkages, some
of which are shown at 608, 610. The scaffold unit 600 different is from that
shown in
embodiments in that a gas strut 612 is mounted at 614 to part of the upper
support platform. The
gas strut 612 extends downwardly in a generally vertical direction. The gas
strut 612 comprises a
two-stage gas strut. A lower and 616 of the gas strut 612 is provided with an
abutment 618 that
rests on an abutment surface 620 that is mounted to a lowered chassis member
622 of the
scaffold unit when the scaffold unit 600 is in a retracted condition. This is
best shown in figure
68. When the scaffold unit is in the retracted condition, the two-stage
gas/612 is fully
compressed.
[00187] Figure 69 shows the scaffold unit 600 in a partly extended
condition. As can be seen,
as the drive units starts to extend the scaffold unit from the retracted
condition, the gas strut 612
applies an upwardly directed biasing force to the upper platform 606. This
assists the drive unit
in initially moving the scaffold unit out of the fully retracted condition. As
can be seen in figure
69, as the scaffold unit continues to extend, the gas strut 612 also extends
so that the intermediate
portion 624 and the lower portion 626 of the gas strut 612 become fully
extended. When the gas
strut 612 is fully extended, the scaffold unit 600 has been extended to a
position that is
sufficiently high such that the drive unit can continue to extend and raise
the scaffold unit
without assistance of the gas strut. As shown in figure 69, as the scaffold
unit 600 continues to
extend, the abutment member 618 moves upwardly and away from the abutment
surface 620.
When the scaffold unit 600 is moved to an extended position to the retracted
position, the
abutment member again comes into contact with the abutment surface 620 and the
gas strut 612
become is compressed as the scaffold unit continues to retract.
[00188] In the embodiment shown in figure 68 and 69, gas struts may be
mounted at or near
each corner of the upper platform. Alternatively, a smaller number of gas
struts may be used.
[00189] In the embodiment shown in figure 68 and 69, it may be possible to
omit the biasing
blocks 114 to 117 shown in figure 15. Figure 70 shows an alternative drive
arrangement to that
shown in figure 15. In figure 70, the bulk of the drive arrangement is simply
that shown in figure
15 and for convenience and brevity of discussion, similar features need not be
described further.
[00190] As can be seen from figure 70, the biasing means 114, 115, 116 and
117 shown in
figure 15 have been omitted. In this regard, the gas strut 612 may
functionally replace those
biasing means. Further, in the embodiment shown in figure 70, gearbox 650 has
an input shaft
652 that can accept drive from a removable electric motor. Therefore, rather
than having the
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electric motor mounted to the scaffolding unit (which may require that each
platform be
provided with an electric motor), a single electric motor that is connectable
to the driveshaft and
removable from the driveshaft 652 may be used to separately raise each
platform. In another
alternative embodiment, the driveshaft 652 may include or be replaced by a 90
degree gearbox
which will allow the motor to be removed in a vertical direction
[00191] The drive arrangement shown in figure 70 also includes a T gearbox
654 that drives a
ball screw 656 that extends through respective ball nuts 658, 660. The
respective ends of the ball
screw 656 are mounted for rotation with in transverse shafts 662, 664.
[00192] Figure 71 shows a perspective view of the scaffold unit 600 in the
extended position.
The scaffold unit 600 includes four gas struts that are connected in
vertically extend from the
upper deck 606. Three of these are shown at 612, with the fourth one being in
figure 71. A hand
rail 670 can also be seen. Like other embodiments, the hand rail 670 is
mounted to the pivot
points between one of the scissor leg is. However, handrail 670 may remain
connected to the
legs during storage, as is shown in figure 73.
[00193] As shown in figure 72, the central part of the scissor linkage 673
shown in figure 71
includes a lower leg 674 that is pivotally connected by a pivot pin 676 to
upper leg 678. The
scissor linkage also includes an upper leg 680 that is pivotally connected to
a lower leg 682. The
pivotal connection is made by providing a pin 684 having an internal thread
extending through
respective openings in or near the ends of the legs 680, 682 (one of the
openings is shown at
685). A locking washer 686 and a lock nut 687 are used to hold the pivot pin
684 in place. The
locking washer 686 has an internal projection 688 that rest inside key way 689
of the pivot pin
684 to thereby fix the locking washer 686 in position relative to the pin 684.
[00194] The scaffold unit of the present invention provides a scaffold unit
that is very
compact when in the lowered position, thereby enabling easy transport and
storage. The scaffold
unit may be raised to its raised position to provide one or more raised
support platforms to enable
workers to work on higher levels of the building. Further scaffold units may
be mounted on top
of the scaffold unit if greater height is required. A number of units may be
mounted next to each
other so that scaffolding extending along a side of a building can be
obtained. Erection of the
scaffold unit beside a building is much quicker and less labour-intensive than
erection of
conventional scaffolding. In some embodiments, the scaffold unit has linkages
at each corner of
the support frames, thereby providing increased strength and stability.
[00195] In embodiments where the scaffold unit has scissor linkages at each
corner and the
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scissor linkages extend at an angle of greater than 80 when in the erected
position, when the
unit is fully erected the scissor linkages provide minimal interference to
access to the building or
a worksite located adjacent to the work platform. In this regard, as the
scissor linkages are
located at the corners and are extending in any sensually vertical direction,
the scissor linkages
do not extend to any great lateral extent, thereby providing clear space along
the bulk of the
length of the work platform. Thus, the scissor linkages do not substantially
get in the way.
Further, if two or more scaffold units are placed end-to-end, a relatively
unhindered walkway
between adjacent units can be formed.
[00196] Significant other advantages also arise from the present invention,
when compared to
conventional scaffolding units. In particular, the present invention is likely
to greatly reduce or
even eliminate accidents and injuries due to manual handling, falling objects
and fall from
heights during erection and dismantling. The labour force required to install
the scaffolding is
greatly reduced when compared to conventional scaffolding. Indeed, it is
envisaged that only 2
installers will be required to install and erect the scaffold unit of the
present invention at a
worksite. Erection of conventional scaffolding can often require a
significantly larger workforce.
The installation time required to install the scaffold unit to its working
height is also greatly
reduced, when compared to conventional scaffolding. It will be appreciated
that the requirement
for a smaller number of workers to erect the scaffold unit and a more rapid
installation time
means that the scaffold unit of the present invention can be installed at
significantly reduced
costs when compared to conventional scaffolding. A further advantage arises in
that installation
costs of scaffold units of the present invention can be quite accurately
estimated, thereby
providing more certainty in preparing cost estimates and reducing the time and
costs associated
with tendering for projects.
[00197] The scaffold unit of the present invention is provided essentially
as a fully assembled
product from the factory (with only a small or minimal number of removable or
attachable
elements). This reduces the number of loose components and also reduces or
minimises the
likelihood of components going missing. Further, the worksite can be much
tidier and there is
reduced or no need for storage of components on-site. This also reduces
storage costs and
transport costs when compared to conventional scaffolding. Further, smaller
storage facilities
may be used. As a further benefit, it is believed that the scaffold unit of
the present invention
should be able to be certified at the factory where it is assembled, thereby
reducing certification
costs on site.
[00198] In some embodiments, the scaffold unit of the present invention has
a containment
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screen fixed to the scaffold unit. Therefore, as the scaffold unit is erected,
the containment screen
automatically extends and is in place without requiring additional
installation. In some
embodiments, the height of the work platforms can be closely and easily
controlled.
[00199] In the present specification and claims (if any), the word
'comprising' and its
derivatives including 'comprises' and 'comprise' include each of the stated
integers but does not
exclude the inclusion of one or more further integers.
[00200] Reference throughout this specification to 'one embodiment' or 'an
embodiment'
means that a particular feature, structure, or characteristic described in
connection with the
embodiment is included in at least one embodiment of the present invention.
Thus, the
appearance of the phrases 'in one embodiment' or 'in an embodiment' in various
places
throughout this specification are not necessarily all referring to the same
embodiment.
Furthermore, the particular features, structures, or characteristics may be
combined in any
suitable manner in one or more combinations.
[00201] In compliance with the statute, the invention has been described in
language more or
less specific to structural or methodical features. It is to be understood
that the invention is not
limited to specific features shown or described since the means herein
described comprises
preferred forms of putting the invention into effect. The invention is,
therefore, claimed in any
of its forms or modifications within the proper scope of the appended claims
(if any)
appropriately interpreted by those skilled in the art.
