Patent Application
20110147329
The present invention relates to a load transportation system and particularly, but not exclusively, to a high efficiency self-contained load transportation system for use in the building construction industry.
Inherent in the construction industry is the use of powered lifting apparatus to move heavy loads, such as building materials, tools and the like around a building site. In the construction of multi-level buildings, several options are available for the vertical transportation of loads to/from ground level and/or between different storeys of the building. Three of the most common options include tower cranes, scaffold hoists and mast climbers, each of which are optionally used in combination with various cantilevered or scaffold mounted platform arrangements to facilitate the movement of the loads into and out of the footprint of the building structure.
Tower cranes typically provide the best combination of weight lifting capacity, height and reach. However, over-dependence on tower cranes can bring significant disadvantages from a practical, cost and environmental perspective. In practical and cost terms, a high dependency on tower cranes by different parts of a busy building site leads to extended on-site waiting times per unit load to be lifted which consequently increases overall build time and adversely affects overall build costs. In addition, tower crane operation is entirely weather condition dependent and unavailability on this basis can often exceed 20% of the total build time. The need for skilled personnel to operate tower cranes is a further overhead which contributes to overall operating costs in the region of £4,000 per week or more. From an environmental standpoint, tower cranes use large amounts of energy to move loads thus constituting a significant proportion of a building project's carbon footprint.
Whilst alternatives such as mast climbers and scaffold hoists can be used to reduce the dependency on tower cranes, these options are also disadvantageous in a number of respects. For example, they are each relatively complex to install and inevitably cause damage to the exterior fabric of the building thus requiring repair work to be carried out upon their removal. Like tower cranes, they each require skilled personnel for their operation and their external footprint to the building being constructed may preclude their use in highly urbanised city centre sites. Their inherently lower load carrying capacity relative to tower cranes mean larger loads must be subdivided into smaller more manageable sizes thus leading to multiple loading cycles, increased loading time, and therefore increased operating costs.
According to a first aspect of the present invention, there is provided a load transportation system for use in the building construction industry comprising:
Preferably, the hoisting apparatus comprises a jacking means to brace it in position against the floor and ceiling respectively of the internal building structure.
The jacking means is telescopically integrated within the hoisting apparatus and allows it to be quickly and easily installed on a temporary basis at any position within a building under construction having opposed floors and ceilings. The reaction loads experienced by the hoisting apparatus are conveniently absorbed by the building structure itself without the need for any counterbalancing weights.
Preferably, the loading platform is a rolling platform.
For example, an appropriate rolling platform which is fully retractable to be level with the edge of a floor of the building under construction is disclosed in the applicant's European Patent No. EP 1 392 939B.
Preferably, the hoisting apparatus is provided with a telescopically extendable winch arm.
Preferably, the winch arm is telescopically extendable.
Preferably, the winch arm has a maximum reach of at least 6.0 m from the edge of the floor.
The actual extent to which the winch arm extends beyond the edge of the floor will depend upon a number of factors including, but not limited to: (i) the dimensions of the load to be lifted and/or lowered; (ii) any space constraints arising due to surrounding structures; and (iii) the extent to which underlying loading platforms are retractable.
Preferably, the hoisting apparatus has a Safe Working Load (SWL) of at least 3,000 kg.
A three tonne SWL allows the hoisting apparatus to transport a larger proportion of typical construction site loads. Importantly, this order of lifting capacity is sufficient to allow the hoisting apparatus to lift loading platforms.
Preferably, the maximum lifting height of the hoisting apparatus is at least 120 m.
Lifting heights of this order allow the hoisting apparatus to be positioned multiple storeys above the underlying loading platform(s). Importantly, such an arrangement allows the underlying loading platforms to be progressively elevated to higher storeys by the hoisting apparatus as building work progresses, but without the need to also elevate the hoisting apparatus each time. The hoisting apparatus itself need only be repositioned to a higher storey once the loading platforms “catch up”.
Preferably, the maximum lifting speed of the hoisting apparatus is at least 25 m per minute.
Lifting speeds of this order are significantly quicker than scaffold hoists and mast climbers.
According to a second aspect of the present invention, there is provided a method of installing a load transportation system for use in the building construction industry, the method comprising the steps of:
Preferably, steps (i) and (iii) and (v) are performed by a tower crane.
Advantageously, tower crane involvement is restricted to steps (i) and (iii) and (v) of the method since the hoisting apparatus is itself capable of lifting and/or lowering any further loading platforms once it has been installed within the building structure.
Preferably, the method comprises the further step of using the hoisting apparatus to lift one or more further such loading platforms to one or more further underlying storeys and removably installing them thereon.
Loading platforms can be employed on all underlying storeys if required. Alternatively, loading platforms can be used only on selected storeys of the building on the basis of need in order to reduce costs.
Optionally, the method comprises the additional steps of detaching a loading platform from the underlying storey; using the hoisting apparatus to lift it to another underlying storey not having a loading platform; and removably reinstalling the loading platform on the new underlying storey.
In practice, it is unlikely that each underlying floor will be provided with its own loading platform. This is because building work typically advances in stages progressively up through a building and so it is more cost efficient to employ loading platforms at selected storeys on the basis of where building work is actually taking place. Accordingly, assuming that the hoisting apparatus and the loading platform being repositioned are initially spaced by several storeys then such an arrangement allows the underlying loading platforms to be progressively elevated to higher storeys by the hoisting apparatus as building work progresses, but without the need to also elevate the hoisting apparatus each time. The hoisting apparatus itself need only be repositioned to a higher storey once the loading platforms “catch up”.
According to a third aspect of the present invention, there is provided a method of removing a load transportation system installed in accordance with the second aspect, the method comprising the steps of:
Preferably, steps (v), (viii) and (x) are performed by a tower crane.
Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
It is known to use loading platforms to facilitate the transportation of loads into a storey of a multi-level building being constructed. A schematic illustration of loading platforms in use is shown in
Two retractable loading platforms (20) are removably installed (as discussed in further detail below) in the two underlying storeys (14) in vertical alignment with the hoisting apparatus (18). An example of a retractable loading platform (20) is shown in more detail in
Equally, some (14) storeys may not require a loading platform (20) and so it is not necessary for every underlying storey (14) to simultaneously have a loading platform (20) installed. Each loading platform (20) is moveable between an extended position in which a distal end (20a) thereof extends beyond the edge (22) of the floor, and a retracted position. Similarly, a telescopic hydraulic arm (24) of the hoisting apparatus (18) can extend out of the footprint of the building, typically up to 6 m beyond the edge (22) of the floor.
In use, each loading platform (20) is retracted, at least to the extent that its distal end (20a) allows a winch (24a) suspended from the telescopic hydraulic arm (24) to be lowered past it, and subsequently allows a load (L) to be lifted above it without being impeded. Ideally, each loading platform (20) is fully retractable to a point where its distal end (20a) lies at, or inwardly beyond, the edge (22) of the floor. Once the load (L) is lifted above the destination storey (14), the appropriate loading platform (20) is extended out of the footprint of the building and locked in position ready to receive the load (L). Once the load (L) is deposited onto the loading platform (20) it is then moved into the building. Conveniently, loads (L) can be lifted directly from a transport vehicle positioned substantially vertically beneath the hoisting apparatus (18) such that tower crane involvement is rendered largely unnecessary (other than as described below). The reduction in tower crane involvement is not only beneficial in terms of cost, but is also less prone to adverse weather conditions. Furthermore, the reduction in tower crane usage also serves to reduce the overall carbon footprint of the construction project. The entire load transportation process is summarised in the chart in
A major advantage of the load transportation system of the present invention is that expensive tower crane involvement is minimised not only during active use of the system but also during its installation and removal. For example, installation of the system involves the preliminary step of temporarily installing a loading platform for the purpose of loading the hoisting apparatus into the appropriate upper storey of the building. Once the hoisting apparatus is moved into the storey of the building the loading platform can be removed (and optionally relocated at an underlying storey). These are the only two stages of the installation process which require tower crane involvement. The subsequent optional steps of installing further loading platforms at other underlying storeys can all be performed by the hoisting apparatus itself as indicated in the chart in
Similarly, upon removal of the system, the hoisting apparatus can be used to remove all underlying loading platforms. Tower crane usage is therefore restricted to the lifting of a loading platform to the storey where the hoisting apparatus is located, subsequently removing the hoisting apparatus from that loading platform and lowering it to ground level, and finally lowering the loading platform to ground level. The removal process is also summarised in the chart in
A further particularly advantageous aspect of the load transportation system of the present invention is that its hoisting apparatus (18) is capable of relocating loading platforms (20) to new storeys of the building without the assistance of a tower crane. Usually, this will involve moving loading platforms to higher storeys (14) as work progresses up through a building being constructed. If new storeys (14) are constructed after the initial installation of the hoisting apparatus (18) then relocation of the hoisting apparatus itself may be required. However, if the hoisting apparatus (18) and the underlying loading platforms (20) are initially spaced by multiple storeys (14), then several relocations of the loading platforms will be possible before the hoisting apparatus (18) itself must be relocated to a higher storey (14).
The following tabulated information provides a comparison between traditional load transportation systems and the system of the present invention. It considers practical process issues and compares them according to elapsed process time along with the estimated associated costs for each loading system. The effects of the following issues are taken into account:
The foregoing analysis assumes a fixed 17 week hire period for all types of systems. By using the load transportation system of the present invention, significant reductions in load in/out time can be achieved, together with an associated reduction in costs. Whilst the savings over a scaffold platform are more modest, there are still substantial gains to be achieved if the system requires to be relocated during the hire period. Indeed, in all cases, if the load in/out location needs to be relocated, the load transportation system of the present invention is significantly more cost and time effective. A graph of the cost savings to be enjoyed mast climber and scaffold hoist systems per number of loads is shown in
The following table provides a more detailed comparison of the system of the present invention and traditional systems.
Modifications and improvements may be made to the foregoing without departing from the scope of the present invention. For example, the loading platform (18) may be provided with a damped means towards the end of its retracting motion to avoid imparting unnecessary shocks to the load (L). An automatic ramp mechanism may also be provided at the internal distal end of the loading platform (18) to facilitate a smooth transition to the floor of the storey. The jacking means of the hoisting apparatus may be self-jacking
| Number | Date | Country | Kind |
|---|---|---|---|
| 0802093.5 | Feb 2008 | GB | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/GB09/50005 | 1/6/2009 | WO | 00 | 12/3/2010 |
