Final Crane Design

The Final Design

The final design is similar to a gantry crane that would be seen in a workplace/workshop. It has the typical I-beam along the top with two supporting legs to spread the load evenly. However, our design is not just a simple gantry crane. Various other design aspects have been included to incorporate as many selling points as possible. The other design aspects are:

• A-Frame
• Collapsibility
• Unique Folding I Beam
• Stabilising Leg

A Frame

The Crane will be used in a very rough environment (i.e. a disaster area) so after a lot of team discussions and designing it was decided that more support was needed. This was to strengthen the whole system as well as aid on the rough ground environment. The A-frame is simply a bar going across which can easily be removed in the dismantling stages to allow for an easy transfer.

I Beam

A standard I-Beam on a gantry crane is one long piece of metal. This is very problematic for use. The length of the beam would have to be 4.4m long so we could cover the brief. As well as this, the I-beam would be very heavy regardless what material it could be made out of. After much deliberation a decision was taken to split the I-beam into two pieces. We would have 2 pieces at a length 2.2m each. Once this decision was taken a suitable joining solution was needed so that the cane could be the required length.

Hinge Design

The hinge has been designed to allow the I-beam to fold in half. The hinge works across the bottom of the I-beam. It has been placed on the bottom so that when the winch is placed at the centre of the beam the two ends of the I-beam will be forcing on to each other (see diagram).

Stabilising Leg

A third stabilising leg has been added to the standard gantry cranes. This stabilising leg cannot be used on its own. It is only there to stop the sideward movement if any occurs. This was placed there on the assumptions if something was to go wrong how could it be stop from happening?. As can be see from the diagram bellow, a sideways force would cause the crane to start working in a position that has not been designed for. All the Stabilising leg just rests on the ground and takes some tension and if the crane happen to topple over the leg will catch it.

This is one of the most important features of the crane as it keeps the people who are under the berried rubble safe (i.e. no more falling rubble to land on top of them) and it also vitally keeps the rescue works safe.

Collapsibility

As part of the brief, it must fit on top of or in the back of a Land Rover 4x4. This places a huge restriction on how the product will be designed. For instance to take the rubble 4m from the point of lift you could have a 5m long beam (ignoring weight). But this does pose a problem. How will it be transported? Even though they are used in disaster areas there still needs to be safe procedures in place to transport the parts.

Because of this tight constriction on packing space it was decided that each part will be able to be taken into smaller parts so that it can be easily fitted into the back of a 4x4. Each leg folds down away with the I-beam connectors also being remove. As stated before the I-beam can be folded into two pieces of 2.2m in length. This does not directly fit in the back of a land rover but can be placed on the roof. The material chosen allows for a light I-beam that can be lifted.

Engineering Drawings an be found here(please click link)

Advantages

The advantaged of this crane design is that is very flexible. Each leg have the own adjustments allowing for the actual crane to be used on uneven ground (key in disaster areas). The key with gantry cranes and not making them fail is to not allow the I-beam to move from a perfect horizontal position. Our designs allows for the I-beam to remain horizontal.

The stabilising leg does not directly take a large amount of the force – hence why is smaller than the rest of the design but it plays a crucial role if the any extra external forces are applied while lifting a 1 tonne load.

The folding beam can be dismantled if necessary so it can be carried over a 100m length (assuming there are not enough people to carry it) or be placed on the top of a Land Rover.

Disadvantage

The I-beam has to be kept horizontal so each leg needs to have the own adjustment range. This increase the cost of the crane and the amount of setting up/down time taken. If this could be removing it would allow for a much shorter assembling time.

The main disadvantage of this design is the time taken to construct the crane and each time the load changes position the crane will need to be changed. It would take a long time to get up and working but as with everything once it has been completed a few times this could be drastically decreased.

Further Developments

As it is the crane would cost around £2600 (on initial calculations) so a definite further development would be to try and reduce this cost. Currently this would take it out of running with Third World Countries as the cost may be deemed to high. A couple of ways this could happen is to reduce the cost of the material – this may be difficult as it would require the price to change of 7075 Aluminium or alternatively the design could be slimed to the nearest smallest standard size that would work.

Conclusion

Over all the each design aspect has been carefully taken into considerations and calculations run where possible and we believe it is the best design that is suited to disaster areas.