Predict Advantages.

. It should be cheaper as it will be used by countries people with small budgets after disaster.
. It would be moved easily by just a Land rover in its roof rack.
. We do not need the electrical or hydraulic power to use it as it will be used in a desaster environment.
. It can be manipulate easily by hand by 2 or 4 people.
. It will be used mostly over rough terrain.
. It will be strong as it is manufactured in metal (Carbon steel and Aluminium).
. It will load a minimum of 1000kg for about 4 m of distance.
. It should be easy to maintain or repair.

Choosing a winch

In order to ensure the correct winch selection and correct method of use, we have to take in account somes criterias:
faillure to select correct winch and incorrect operation can potentially reduce the life cycle of our winch and result in premature faillure.
Winches used under certain conditions i.e. Salvage, recovery and off road applications will require a winch high rated winch than that of less frequently used winch.
selection of winch capacity for loading needs to be careffuly considered. It should be powerful enough to pull our charge overcoming the resistance caused by obstacles such as moving gradients, mud, sand or stone.
When choosing a winch we should know the maximum effort that the winch can exert on a single line on the first layer of the winch drum.As the layers of cable build up on the winch drum, the overall cable speed increases, however the rated line pull decreases at the same rate.
I think by using snatch block to obtain a double line pull we can in effect almost double the pulling capacity of our winch, whilst approximately halving the overall recovery speed.

Final Objectives

The following objectives need to be completed for tender:

Stress analyst - Stress evaluation on final design to be passed to chief designer for modelling.

Chief designer - Cad of final model and individual assemblies to be uploaded and dimensions passed onto Financier for pricing

Financier & Materials Specialist - Finalise cost of specified lengths of material and amounts to be passed worked on in conjuction with Financier. Final pricing and passed on to PM for close of tender and final litigation.

Project Manager - Tie up any loose ends regarding the tender and to assist in all areas. Finalise Tender.

After tender - All group members must be present to construct presentation of the project to be shown on 28/04/2010

NB - Individual mini- reports need to be collated by 7 days time explaining how the tender went from your point of view, likes/dislikes, drawbacks, achievements and could-have-done- betters.

Final Assembly Drawing

With the final CAD design finished I was able to then produce a 3rd Angle Orthographic Assembly drawing showing the dimensions of the crane design. The drawing also includes a bill of materials showing what type of material will be used for each part and also showing the part on the isometric view (top right). This drawing will then enable our finance officer to be able to draw up figures in ragards to the cost of the crane materials.

Final Design Assembly

This is the final design assembly for the crane. The structure is standing on four legs which are flexible and move independantly of each other, offering a stable support especially on uneven terrain. the main boom which will take the load is supported by a cable running from the two supporting Steel I-beams on either side. The eye bolts used with this cable can take maximum 750KG loads each and therfore they are more than suitable for our use. This will help in distributing the load across the 3 beams. the 4 pulley system will be hooked onto the eye bolt which is bolted onto the undersurface of the main boom. The eye bolt can take loads of up to 1.5 tonnes therefore it is more than suited for our 1 tonne max. The pulley system is then connected by means of winch (see previous posts) which has a 10 to 1 ratio.

As these beams will be made from steel, each of the parts on the strucure weighs a comfortable weight for two people to be carrying over short distances. Also this crane will be easy to assembly as it incoperates simple bolts and also benefits from some of the parts coming pre-machined. The legs will be kept secure at the required height by means of pins being threaded through the hole features found on the leg.

Not only do the straight I-beams have support but also the main boom has been modified to include a support system through the square steel tube. With the circular base connected to the underside by means of ball bearing, the structure is able to rotate indipendantly of the underside base.

Leg Design

This is the leg design we will be going with for our crane. In designing, it was important to make sure that we kept in mind the fact that the crane will be used mostly on rough terrain. Therefore the support for the whole crane structure needed to be flexible but still maintain structural strength. The led to the chosen design as shown above.

Each of the legs can be moved independantly from each other and then kept at that position by means of a steel bolt put through the corresponding hole. If position needs to be changed this can be done easyliy by repeating process with corresponding hole position.

Having constracted the supporting legs a way of connecting base to legs had to be designed.

The above illustrations show the fixings that will be used to connect the base to the crane legs. This will be done by a standard bolt bolted through the lower base and the legs at eacg of the four intersections as shown. The Upper base will not have any direct connections with the legs as this will allow for the rotation of the plate through the ball bearings between the Upper and Lower bases.

Materials Update

Due to the disapperance of The Materials specialist he has been vacated from the group and the materials work is spread between the rest of us.