Tender Proposal

Design

Early-on we decided to go with a crane with a rotating boom as we thought this would be the most efficient and practical way of transporting the load.

However to achieve this the length of the boom would need to be at-least 2m to transfer the load 4m from the point of lift. We realised that a 2m beam would be too heavy and large to transport.

To overcome this problem we split the beam into two half's of 1.1m and 1.2m respectively. These two beams would be joined together using this part:-

Each beams will be connected to the I-beam connector by 5 M16 hex bolts, hence insuring structural stability while solving the problem of making the crane portable.

Another feature of the design is hinged leg joints:-

This part of the design allows the crane to be stable while on uneven terrain by adjusting the height of the feet.

This part will be connected to the feet which will clamp to the floor to give the crane a more rigid feel. The feet will be interchangeable so according to the terrain the correct feet can be used.

Here is what the finished crane looks like:-

Detailed Drawings of Each Part

1.1m Beam

1.2m Beam

Center Console

Feet-Leg Connector

I-Beam Connection

Large Leg

Large Leg Connector

Small Leg

Small Leg Connector

Assembly Drawing with Bill of Materials

(not sure why the pictures are not click-able e-mail me at razaqa@aston.ac.uk if you require better pictures)

(Asrar)

Manufacture and Fitness for Purpose

After extensive researching and brainstorming with the group meeting we decided to use an I-Beam instead of a solid Block or T-Beam.

Reasons

1. An I-Beam is generally used for construction and heavy weight lifting purposes this is because it is more stable and deflects less than the T-beam and has a significant amount of weight less than a Solid Block.
2. If the amount of material used to produce a I-Beam is less obviously the amount of material used would be less thus reducing the final cost of the product.

After this decision and extensive research on different materials their densities and Young’s modulus calculations were done to calculate the maximum deflection a beam would be able to withstand and the amount our beam would deflect under the maximum load specified. These values came up to be at about 9.28*10^-3m the maximum deflection and 4.2*10^-3m which was the deflection the I-beam would have under the maximum load. This proved that the choice of material, which was carbon steel and length is appropriate so the beam will not fail under maximum conditions.

Calculations were also done to calculate the maximum compression on the centre part which came up to about 960KN and then we did some calculations to calculate the compression which it will undergo under the maximum load. We added another 4000Kg in the calculation just to be sure. So the end result was that the maximum compressive force that the centre piece made up of aluminium alloy can withstand is 960KN and the compressive force with 5000Kg would be 50KN which is considerably less than the earlier value and this is under much more weight than the required amount. So this proves that the material used in the centre part is appropriate and it will not fail under maximum conditions.

(Zaeem)

Finance

Component	Mass	Material	Quantity	Cost
Hand Winch			1	£90.95
Pulley			1	£7.64
Wire Rope			1	£32.90
M8 Bolts			100	£5.61
M8 Nuts			100	£2.21
M8 Washers			100	£0.90
M16 Bolts			50	£17.99
M16 Nuts			100	£12.95
M16 Washers			100	£4.87
Boom	117Kg	Carbon steel	1	£52.61
Centre console	98.018Kg	Aluminium	1	£148.28
Large leg connector	24.621Kg	Aluminium	1	£37.25
Small leg connector	10.327Kg	Aluminium	1	£15.62
Feet	5.85Kg	Aluminium	3	£26.55
Small leg	2.757Kg	Aluminium	3	£12.51
Large leg	3.848Kg	Aluminium	3	£17.46
I-Beam connection	2.104Kg	Carbon steel	1	£0.95

The total cost of our crane = £487.25 (excluding manufacturing and labour costs)
(Daljinder)

Conclusion

We have not as yet received accurate costs from manufactures of the cost of labour and manufacture but many companies have quoted us a price in the region of £300.

This will bring the total cost of the crane to £787.25; we will be looking for a unit retail price of £1000 with a 10% discount for buys over 100 cranes.

We think this is a very competitive price and you can be rest assured the quality of our product will be second to none, we are very proud of the reputation our company has achieved over the years and will not let you down.

We look forward to your reply

(Hani)

Beam Deflection

In addition to the requirements for the beam to safely carry the intended design loads, there are other factors that have to be considered including assessing the likely deflection of the beam under load. If beams deflect excessively, then this can cause visual distress to the users of the crane and can lead to failiure.

Beam design is carried out according to principles set out in Codes of Practice. Typically, the maximum deflection is limited to the beam’s span length divided by 250. Hence, a 5m span beam can deflect as much as 20mm without adverse effect. Thus, in many situations it is necessary to calculate, using numerical methods, the actual beam deflection under the anticipated design load and compare this figure with the allowable value to see if the chosen beam section is adequate.

So using the ratio method and this principle the allowable deflection in the beam would be:

5:0.02=2.3:x

5x=0.02*2.3

X=(0.02*2.3)/5

X=9.2*10^-3m

Earlier calculations indicated that the beam was going to deflect only about 4.2*10^-3 which shows that the beam will withstand the required deflection and the material used is appropriate.

Force on Bolt

Deflection Calculations

After extensive research these were the materials that were taken into account while the material for the crane was being decided.

Crane feet thought process

Material and Type of foot of the Crane
Initial thoughts:
In order the portable crane to be steady, the feet need to be made from quality material and be able to hold the crane on different types of ground (for example, the ground could be uneven, even wet and muddy) without slipping and without damaging it as well.
Initial ideas:
-For the best grip, some kind of rubber can be used but it should be rugged and shouldn’t skid.
With extensive use, it can get loosened and can get harder so more slippery.
But these will only be suitable where the floor is hard.

Initial Sketch:

-My second idea was to use some sort of spikes for the crane so that it can be used outdoors where it is muddy or grassy.

They could be made from stainless steel, aluminium or from titanium.

But they cannot be used them on soft surfaces, like wood, or indoors. They could damage the floor

The disadvantage of spikes is that they are made from metal and can therefore start to rust if they are exposed to water (especially sea water). Also they should be cleaned and dried after use.

Examples found after research:

Conclusion after thinking:

The conclusion which I have come up with is to combine the rubber and spiked feet together with some rotating mechanism, which moves 90 degrees and has rubber on one side and a spike on the other. This has to be discussed with the group in the next group meeting.

Additional thoughts

Thought process

Stability won’t be an issue in this case but the size is. This idea for the base seems to be suitable for the requirements given to us.

Thought process

Going over the pros and cons of the different concepts the two options to be considered are either three legs or four.

With three legs the amount of material being used will reduce but the weight has to be taken into account. As with this design there are three adjustable telescoping legs which will be suitable for rough terrain and the feet must have some sort of rubber feet to avoid skidding which is another factor which has to be taken into account.

These factors can also be applied to a four legged structure this part has to be discussed with the second member designing the base.