Note: Descriptions are shown in the official language in which they were submitted.
CA 02728798 2013-06-07
1
A SYSTEM COMPRISING A MOVABLE WORK PLATFORM, AS WELL AS
AN APPARATUS AND A CRANE DEVICE
Field of the invention
The invention relates to a system comprising a movable work platform and a
lifting device for the manipulation of loads and weights. The invention also
relates to an apparatus. The invention also relates to crane device.
Backaround of the invention
Aerial access platforms, such as elevating work platforms supported by a
mast, and structures of them, are known and applied, for example, at various
sites of construction and renovation of buildings, as well as when performing
various maintenance or repair operations. Work platforms normally comprise
a horizontal frame structure, by means of which workers, tools and other
equipment and materials needed can be elevated to a desired height for
performing work. The work platform is typically solid and elongated, but the
work platform may also have a deflected shape, it may comprise protrusions
or even have a circular shape, depending on the needs of the worksite. Nor-
mally, the work platform has a rectangular shape and the flooring belonging
to its frame structure is delimited by safety rails. The workers move on the
flooring.
The work platform is moved along a vertical mast structure comprising of, for
example, a lattice structure which normally has a square cross-section. The
mast structure remains stationary and it may be free standing, but typically,
the mast structure is supported in place by means of fasteners. The mast
structure may also be supported at several different points, for example, to a
building, by means of fasteners. Yet, the fasteners make it possible that the
work platform can move past them up and down along the mast structure.
The bottom end of the mast structure may be supported to a particular foot-
ing or the like, but the work platform may also be movable, in which case the
mast structure stands on a movable base. The movable base is formed, for
example, by a carriage on wheels, which can be connected to a hauling vehi-
cle. The bottom part of the mast structure and the work platform are placed
CA 02728798 2013-06-07
. ,
,
2
on the movable base. The rest of the mast structure can be dismounted and
transported separately. Part of the frame structure can also be folded up or
even removed, in which case the length of the base to be transported can be
reduced. Typically, the movable base comprises several supporting feet
whose position can be changed and which support the mast structure when
the work platform is in use.
There may also be several mast structures for a single work platform. It is
also possible to connect two work platforms, each comprising one mast
structure. In this way, it is possible to provide a larger work area or a
greater
loading capacity.
The work platform is moved along the mast structure by means of a lifting
and lowering device provided between the mast structure and the work plat-
form, connected to both of them or integrated in the frame structure of the
work platform, for example its lifting frame. The lifting and lowering device
comprises actuators, for example an electric motor and a transmission that is
coupled by means of one or more drive pinions to a gear rack in the mast
structure. The pinion ascends along the gear rack, and simultaneously the
whole work platform moves along the mast structure. Furthermore, the lifting
and lowering device comprises a control system which is also provided with
the necessary control means for controlling its operation, for example manu-
ally. The control means are normally placed in such a way that a person on
the work platform can move the work platform to a desired height or all the
way down, wherein it is possible to exit the work platform or load goods.
If necessary, a single control system can be used for controlling several
lifting
and lowering devices and for keeping the work platform in balance.
At construction and renovation sites, it is often necessary to lift and lower
various weights or loads. Said weights and loads may be on work platforms
or elsewhere, for example on the ground, from where they are lifted and
transferred to a desired location. For this reason, the mast structures or mov-
able work platforms are provided with cranes or pivotable boom structures
with the necessary equipment for lifting and lowering loads, for example by
means of a hoisting wire rope and a hook.
CA 02728798 2014-08-18
3
Some known examples are disclosed, among other things, in document JP
6336823-A, in which the crane is connected to a particular lifting and lower-
ing device, as well as in document WO 03/097509 Al, in which the crane can
also be provided with a work platform for the operator of the crane. In addi-
tion to this, the same mast structure may be provided with a separate work
platform, such as in WO 03/097509 Al, in which the work platform is placed
lower than the crane. The crane can also be placed directly on top of the
work platform, or connected to the frame structure or integrated in the
lifting
and lowering device of the work platform, as in documents JP 8208155 A, US
4498556 A and DE 4033492 C2. In FR 2528815 Al, the crane is mounted on
top of the lifting and lowering device, and said lifting and lowering device
ele-
vates a lift cage which is used for the transportation of workers. The crane
is
mounted to the mast structure in a movable manner, and it is connected to
the lifting and lowering device.
The weights to be elevated and transferred exert loads on the lifting and low-
ering device which is also subjected to the load caused by the work platform.
In a corresponding manner, by means of the lifting and lowering device, the
loads are effective on the mast structure which must bear the loads caused
by the crane, the load in the crane, and the loads caused by the work plat-
form, among other things. For example, the structure disclosed in said FR
document is supported to the mast structure by means of three supports on
top of each other, consisting of rollers. It is obvious that at the middlemost
support, a load force is effective that tends to bend both the lifting and low-
ering device and the mast structure. Reinforcing the structures and increas-
ing the strength often lead to an unnecessary increase in the size of the
structure, an excessive weight and extra costs as well as more complex
manufacture.
CA 02728798 2013-06-07
4
By means of the presented apparatus, the loads of the mast structure are
influenced in such a way that particularly the bending load forces can be
reduced. Said apparatus makes it possible that the loads caused by the work
platform and particularly the crane are effective at different points of the
mast
structure and not at the same point, which would be disadvantageous. In
particular, it is possible to reduce considerably the load forces transmitted
from the apparatus to the work platform, which facilitates the design of the
work platform and improves its strength to a great extent. Said load forces
are caused by said apparatus, crane, or other weights and loads. The possi-
bilities of varying the work platform remain good, because the apparatus and,
for example, the crane can be constructed separately and placed as a sys-
tem structurally separate from the work platform. It may also be possible to
replace the work platform or the apparatus irrespective of each other, if nec-
essary. It is even possible to remove the apparatus totally, if it is
unnecessary
at the work site, but it is not necessary to remove or replace the work plat-
form. By means of the apparatus, it is even possible to add a crane in old
mast structures, and the replacement of the work platform will not be neces-
sary.
By means of the presented apparatus construction, the support, which con-
sists of, for example, rollers, can be placed as low as possible in relation
to
the work platform. This has not been possible earlier. The support, mounted
far below the work platform, has prevented the lowering of the work platform
as low as possible.
The frame structure utilized in the apparatus is suitable for use not only for
cranes but also for other lifting and transfer devices as well as for other
pur-
poses, such as merely the transportation and carrying of weights. The
weights and loads can also be connected directly to the frame structure.
Instead of the crane, it is alternatively possible to connect machines,
devices
and structures, for example according to the needs at the worksite, even
other working levels or work platforms, to the presented frame structure. The
frame structure can also be provided with aerial work platforms equipped with
a boom. By means of the presented solution, the loads of these are not
effective on the work platform but on the mast structure.
CA 02728798 2013-06-07
By means of said frame structure, it is even possible to improve work plat-
forms of prior art in such a way that the work platform is supported not only
to
the mast structure but also to the frame structure. The frame structure trans-
mits load forces to the mast structure by means of its own structure. The
5 connection between the frame structure and the work platform is floating,
which enables a sufficient support but also their movement in relation to each
other.
Brief description of the drawings
In the following, the invention will be described in more detail by means of
some examples and with reference to the appended drawings, in which
Fig. 1 shows a system of prior art, which comprises a mast structure
and in which the presented apparatus can be applied,
Fig. 2 shows an example of an apparatus provided with a crane,
Fig. 3 shows a system comprising the apparatus and crane shown in
Fig. 2,
Figs. 4 and 5 illustrate the operation of the system shown in Fig. 3, where
the
frame structure and the work platform move in relation to each
other,
Fig. 6 shows another example of an apparatus provided with a work
platform,
Fig. 7 shows a system comprising a work cage, and
Figs. 8a, 8b and 8c show some rail structures.
Detailed description of the invention
Figure 1 shows a system of prior art comprising a mast structure 1, a work
platform 2 which can be lifted and lowered and which comprises a frame
CA 02728798 2013-06-07
,
6
structure 3 with a flooring. The railings 4 bordering the flooring also
comprise
gates 5 and steps 6 for climbing to the work platform when the work platform
is in the lowered position. The work platform 2 is mounted to the mast struc-
ture 1 by means of a lifting and lowering device 7. The lifting and lowering
device 7 comprises the necessary control devices for lifting and lowering the
work platform 2 together with the lifting and lowering device 7 in such a way
that the work platform 2 moves along the mast structure 1. In this example,
the control devices comprise a drive pinion which functionally engages a
toothing provided in the mast structure 1.
In the example of Fig. 1, the mast structure 1 is placed on top of a movable
base 8. The base 8 constitutes a haulable carriage, and it comprises several
adjustable supporting feet 9. The mast structure 1 can be extended by
means of module structures to a desired height, and furthermore, it can be
mounted to a building or other structures, if necessary, by applying fasteners
to support and brace the mast structure 1. The system of Fig. 1 is also well
described by the features which have already been presented earlier.
Figure 2 shows an example of a novel apparatus 10, in this case particularly
for the lifting and transfer of loads, which apparatus can be connected e.g.
to
the mast structure 1 of Fig. 1 in such a way that it can move along the mast
structure 1. Said apparatus makes the above-presented advantages possi-
ble. In combination with the work platform 2, the apparatus 10 constitutes a
system with very versatile uses at various worksites.
In the example of Fig. 2, the apparatus 10 comprises a crane 11 whose prin-
ciple of operation is based on a knuckle boom crane which also has a rotary
movement around a vertical axis of rotation. The crane 11 comprises two
boom parts which are movable in the vertical direction and are connected to
each other by a joint. One boom part is connected by a joint to the frame 12
of the apparatus. In this example, the outermost boom part is telescopic,
wherein its length is changeable. The telescopic structure or the joints of
the
boom parts are not necessary, but by means of them, the reach and the
operating range of the crane 11 can be increased significantly, as well as by
means of said rotary movement.
CA 02728798 2013-06-07
7
With respect to the structure of the crane 11, it is possible to apply compo-
nents, actuators, control systems and control means which are known as
such from the structures of cranes applied in, for example, vehicles or vari-
ous working machines. In this example, the boom parts and the rotary
movement of the crane 11 are controlled by means of cylinders and pressur-
ized medium. The control system used for controlling the crane 11 applies,
for example, control valves known as such, which are operated electrically or
manually and which control the pressure in the cylinders and the flow of
pressurized medium.
If necessary, the control system produces the volume flow and the pressure
of the pressurized medium by means of a pump, or the pressurized medium
required by the apparatus 10 is obtained from an external source. In some
examples, the pressurized medium is produced by means of a pump at the
apparatus 10, at the work platform 2 or even at the movable base 8, from
where the pressurized medium is led by hoses or pipes via the control valves
to cylinders or other actuators, such as motors. The control system com-
prises the necessary manual control means for the control of the crane 11,
and they are normally placed within the reach of the operator, for example at
the work platform 2. The control system can be primarily based, for example,
in connection with the frame 12. The control system can also be operated by
remote control, so that the necessary manual control means can also be
placed in the remote control which can be carried with the work platform 2, or
elsewhere.
The outermost boom part is provided with the necessary connecting means,
to which e.g. a lifting hook or lifting ropes can be connected. In one
example,
there is only one boom part, and in other examples, there are more than two
boom parts. In an example, the rotary movement of the crane 11 is not
implemented. In an example, as shown in Fig. 7, a small work platform or
work cage 25 is connected to the outermost boom part, wherein the crane 11
is intended for moving the work cage in such a way that a worker in the work
cage has access close to the object. In the structures of said work cage and
work platform, it is possible to apply solutions which comply with the prior
art.
CA 02728798 2013-06-07
8
In the example of Fig. 2, the frame 12 comprises a cylindrical vertical struc-
ture, to which the crane 11 or a corresponding lifting device is connected.
According to the example of Fig. 6, it is also possible to apply various
girder
and lattice systems consisting of a single element or several separate ele-
ments in the frame 12. A lower support 13 is mounted to the lower part of the
frame 12, by means of which support the frame 12 can be connected to the
mast structure 1 in a movable manner. The lower support 13 comprises, for
example, a square braced structure with supporting rollers which are placed
against the mast structure and roll along the same. The supporting rollers are
placed in the braced structure in such a way that they keep the lower part of
the frame stationary in the horizontal direction with respect to the mast
structure 1. In this example, the lower support 13 is implemented by means
of eight supporting rollers which are placed substantially at the same height
and are placed against the four sides of the mast structure 1. The braced
structure can be dismounted or opened so that the crane 11 and the frame
12 can be installed in their place. In the example of Fig. 2, the braced struc-
ture is partly open, but it may also be closed.
An upper support 14 is mounted to the upper part of the frame 12, by means
of which support the frame 12 can be connected to the mast structure 1 in a
movable manner. In this example, the upper support 14 and its structure
comply with the same principles as the lower support 13. Naturally, the
structures of the supports 13, 14 may also differ from each other, but in view
of the manufacture, it is simple that they match each other. Typically, the
crane 11 is connected to the frame 12 substantially at the same height as the
upper support 14, or it is slightly higher than that.
In the example of Fig. 2, the crane 11 is connected by a rotary pillar 15 to
the
upper part of the frame 12, as an extension to the frame 12, and an actuator
16 for rotating the crane 11, that is, a cylinder with a changeable length, is
connected to the pillar 15 on one hand and to the upper support 14 on the
other hand. An actuator 17 for lifting and lowering the first boom part, that
is,
a cylinder with a changeable length, is connected between the pillar 15 and
said boom part.
CA 02728798 2013-06-07
9
The upper support 14 and the lower support 13 are placed at a suitable dis-
tance from each other in the vertical direction so that, for example, load
forces caused by the weight of the crane 11 or by the manipulation of loads
and weights and being effective on the supports 13, 14 and the mast struc-
ture 1 would be sufficiently low. The magnitude of the load forces is influ-
enced particularly by the vertical distance between the upper support 14 and
the lower support 13. The load in the crane 11 causes a moment of torque
whose magnitude depends, among other things, on the horizontal distance
between the load and the upper support 14. For example, the lower support
13 must compensate for the moment of torque in such a way that the lower
support 13 is supported to the mast structure 1, simultaneously causing a
horizontal load force. An increase in the distance between the lower support
13 and the upper support 14 will result in a decrease in the horizontal load
force, respectively. At the same time, the load of the frame 12 is also
decreased. Thanks to this, the structure of the frame 12 can be made lighter,
and its elongation will not excessively increase the weight of the whole appa-
ratus.
In one example, the distance between the upper and lower supports 13, 14 is
also adapted in such a way that the apparatus can be connected to the mast
structure 1 of Fig. 1 in such a way that the work platform 2 is placed between
said supports. In an example, the supports 13, 14 are placed directly below
and above the work platform 2 and the lifting and lowering device 7. In the
examples of Figs. 2 and 3, the distance is so great that the work platform 2
in
combination with the lifting and lowering device 7 is capable of moving inde-
pendently in the vertical direction in the area between the supports even
when said supports and the frame 12 together do not move. The upper sup-
port 14 is placed above the work platform 2, and the lower support 13 is
placed below the work platform 2.
In the example of Fig. 2, as well as in the example of Fig. 6, the apparatus
is
not equipped with a separate lifting and lowering device, by means of which
the apparatus would move along the mast structure 1. In this way, a structure
is achieved which is as simple and reliable as possible. Pushed by the work
platform 2, or preferably by the lifting and lowering device 7, the apparatus
is
moved upwards. The apparatus moves downwards with the platform 2, until
CA 02728798 2013-06-07
the lower support 13 encounters the lower part of the mast structure 1 or
another corresponding obstacle and stops in place, which situation is illus-
trated in Fig. 4. When allowed by the distance between the supports 13, 14,
even after this the work platform 2 may move down to some extent, which
5 situation is illustrated in Fig. 5. This is possible because the
apparatus is
structurally separate, for example, from the lifting and lowering device 7.
Consequently, the work platform 2 can be driven down without being
restricted by said apparatus, wherein climbing to the platform and unloading
or loading are easy.
The apparatus, for example its upper support 14, can also be temporarily
connected or locked to other structures, such as the lifting and lowering
device 7. In spite of the locking, the structures and their operation may com-
ply with the principles presented in this description. It is also possible to
lock
e.g. the upper support 14 or the lower support 13 or both of them by means
of a brake, whereby in the situation of Fig. 2 the work platform 2 can be low-
ered down to some extent so that said apparatus remains stationary. The
apparatus may thus, if necessary, comprise the necessary brake devices for
keeping it in position.
Figure 3 illustrates the operation of the apparatus of Fig. 2 in the system of
Fig. 1. The structure of the lifting and lowering device 7, which in this exam-
ple extends some distance above the work platform 2, is supported to the
upper support 14 and pushes it upwards. In the example of Fig. 2, the upper
support 14 or any other structure of the apparatus is not connected by fas-
tenings to the structure of the work platform 2 or the lifting and lowering
device 7. The lifting and lowering device 7 carries the apparatus of Fig. 2.
In
the example of Fig. 3, a weight 17 has been transported with the work plat-
form 2 to the upper part of the mast structure 1. The lower support 13
remains at a distance from the work platform 2 and its frame structure 3. The
frame 12 connecting the supports 13, 14 passes the work platform and is
also placed outside the work platform 2, adjacent to it, wherein it is not nec-
essary to make changes in the work platform 2 because of the frame 12. As
already noted earlier, the frame 12 can be a girder and lattice structure con-
sisting of a single element or several separate elements. The work platform 2
and the frame 12 move along the mast structure 1 by means of the lifting and
CA 02728798 2013-06-07
. .
11
lowering device 7. The moments of torque effective on the frame 12 and the
supports 13, 14 cannot affect the work platform 2 or the lifting and lowering
device 7 which is only subjected to the vertical load force caused by the
weight 17 and the total mass of the apparatus shown in Fig. 2.
According to the apparatus example shown in Fig. 6, the frame 12 that con-
nects the supports 13, 14 passes the work platform and extends through the
work platform 2. The work platform 2 is supplemented with a connecting part
18, by which the load forces of the work platform 2 can be transmitted to the
frame 12 and further via it to the mast structure 1. In this way it is
possible to
provide work platforms which are longer than normal, and their protrusions,
because the loads can also be distributed by means of the supports 13, 14.
In this way, the loads are not transmitted to the mast structure merely by
means of the lifting and lowering device 7. In this example, the frame 12 is a
vertical beam structure placed next to the mast structure 1. The work plat-
form 2 and the frame 12, which are also separate in this example, move
along the mast structure 1 by means of the lifting and lowering device 7. The
frame 12 is capable of moving in relation to the connecting part 18 which
comprises, for example, supporting rollers rolling along the frame 12.
To achieve the above-presented advantages, the mast structure can in some
examples also be replaced by a rail structure, to which the work platform is
connected, for example by means of the lifting and lowering device, or to
which the apparatus according to the example of Fig. 2 or 6 is connected.
The lifting and lowering device 7 comprises the necessary actuators for
lifting
and lowering the work platform together with the lifting and lowering device
in
such a way that the work platform moves along the rail structure. According
to an alternative, the lifting and lowering device is separate from the work
platform and is arranged in connection with the rail structure, for example at
its upper end. The lifting and lowering device is connected to the work plat-
form by means of, for example, one or more coilable wire ropes. Figures 8a-
8c show some examples of a rail structure 19 which is connected to a build-
ing. The rail structure 19 consists of, for example, one or more I-beams. A
dash-and-dot line depicts the connection of the work platform or said appa-
ratus to the rail structure.
CA 02728798 2013-06-07
,
,
12
The invention is not limited solely to the above-described examples and the
alternative shown in the drawings, but it can also be applied in the scope
defined by the appended claims.
