Financial Report

I have collected together available costs for the materials involved with the crane. This includes the screws and bolts, the I-beam and the square bar stock. All cost estimates are approximate values applied to existing products with the nearest possible measurements.

• Stainless Steel M10 Bolts - £28.36 per 100 (ScrewFix)
  
  

• Stainless Steel M10 Nuts - £12.38 per 100 (ScrewFix)

• Aluminium Alloy Current Cost - $2005 / Tonne (London Metal Exchange)
  This aluminium alloy would be used for the connection block attaching the legs components together and the feet etc. The connection block would most likely be sand casted for the one-off batch of 100 whilst the other components could either be, again sand casted or machined from block or plate material.

• Aluminium Alloy I-Beam - $194.70 (Onlinemetals.com)
  The costs for this are in relation to an 84” aluminium alloy 6062 I-beam when in reality, our proposal beam is aluminium alloy 7075 at a length of 86.6”.

• Aluminium Square Bar Stock - £21.52 / 1000mm (Metals 4 U)
  The profile dimensions involved with this cost are similar. There is approximately 9500mm of bar stock needed per crane (excluding scrap needed for facing off ends etc). This equates to £215.20 per crane.

• Winch - £215
• Trolley - £60
  

When adding costs i considered labour:

• 2 Assembly/Test Technicians - £15000 - £18000 salary.


• 1 Manufacturing Engineer (initially) – They would be needed initially to set-up the production area and ensure that the assembly build process moves along quickly and efficiently with minimal scrap. The costs for this would be for depended on how many hours it takes for them to set-up the production area.


• Quality engineering – They would be needed to ensure a consistency of quality is achieved throughout the batch. I would estimate they would check the critical dimensions of 1 crane for every 10 cranes manufactured throughout the batch of 100.
  
• Stores and Goods In/Out – To help deliver the finished cranes and to store and catalogue the materials ready for manufacture and assembly.

Packaging and delivery is also taken into account.

I have also added a small profit and an extra cost to accomodate for any margin of error that may and will likely occur. It is always best to accomodate for this margin of error for such cases and a bad batch ths extra materials needed or if any raw materials/bought components go up in price.

When considering all these factors i would again have to say that my initial cost proposal of £2600 per crane if a safe estimate.

Mechanics and Calculations

During development of our gantry crane many calculations and formulae were taken into account. Without using these formulae it could not be certified for prototyping. We wanted to make sure the crane fit the required specification within a safe margin and was suitable for the task at hand. Below are the developmental calculations and figures.

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.

Background Costing Research

Whilst trying to figure out the rough cost i should be aiming for i considered several factors:

• The crane would need to be as cheap as possible without reducing the quality overmuch.
• The crane should be no more expensive than our competitors unless there are features on our crane that are specific to this design only and thus making it worth the extra money to the customers.
• Our main target audience is relief aid organisations and governments where there is a high risk of natural disasters such as earthquakes etc. Generally speaking, this type of customer will have minimal financial resources available and so the crane will need to be cheap enough to accomodate this.
• Whilst deciding the material, the costs involved will need to be considered as the better quality, stronger/lightweight materials will be more expensive.

With these sorts of factors in mind, i decided to research our competitors and see how much they are selling their cranes for. I managed to find 5 gantry crane companies both located in England and in America. Their selling prices ranged from £2000 to £3500 approximately (this does not include delivery costs). This tells me, that i would ideally be aiming to be in the cheaper half of this range but not the cheapest as we have an added market advantage of being one of the few cranes on the market that has a high level of portability.

Suitability of material

Now with the calculations completed I can compare the forces which the material will be under with its yield stress.

To recap the values for Aluminium 7075:

Specific Density: 2810 Kg/cb.m

Youngs Modulus: 72 Gpa
Yield Stress: 145 x10^6 pa
USD/LB: 0.97

The calculated stresses &forces:

Max stress experienced: 69 MPa

Max deflection: 0.015 m

As it can be seen the 69 Mpa is well below the materials yield stress of 145 MPa therefore this material will not deform when it is fully loaded which is very desirable. It will also not deform when the beam is at its max deflection as aluminium 7075 can deflect 9-10% before plastic deformation.

Therefore Aluminium 7075 is perfect for this crane as it is light, strong and reasonably priced.

Coating

Aluminium 7075 can also be easily anodized which increases the thickness of the naturally occurring oxidized layer. This layer increases corrosion and wear resistance, as well as creating a good base layer for paint primers and glues than bare metal. This is useful as the crane has to be transported, carried and repeatedly put up and taken down. This would mean that there would be a lot of wear on the crane and it might also be bumped by debris in the disaster zone.

Conclusion

Our product merges versatility,utility, effectiveness and reliability, into one stable disaster zone crane. Its over engineered features and design compliment its harsh surroundings and will be an effective tool in future earthquake prone areas. Its ability to be carried further through use of modern materials and design mean that the crane can be deployed faster in worsening conditions to the task of saving lives. Its simplicity means any relief worker, locals, or officials can use and operate this crane.

Its Compact Gantry crane design enables it to be comfortably folded , stored and transported on any pick up or 4X4, but also here at the team HQ innovation also takes a priority and the crane, comes with stabilising legs as standard, the first one of its kind.

Do not be fooled by other companies , half attempted efforts, fancy swivel cranes and non complete cranes. Not only are they ineffective , simply most do not work.

Our crane has been tested numerically for reliability throughout, it is not going to break at rated loads or buckle under ever increasing stresses. This is a quality assured product.

Even its price , is very comparable to other companies unrealistic "prices", for our price you acquire space age materials and design for less.

Overall by buying with us,you are getting an effective, value for money product that will serve with pride in disaster relief zones.

Engineering Drawings

These are the engineering drawings of all the different parts of the crane. Dimensions are included.

Nuts and Bolts Material

The nuts, blots, pins and fixings used in this crane would not be made of aluminium as this would cause many problems. Aluminium is too expensive to make small components out of, which means that if any were lost or misplaced (which would be very likely in the chaotic environment of a disaster zone) it would be very expensive to replace them. Also there will be more shear stresses and torsion stresses on these fixings so it is better to air on the side of caution and make them of a stronger metal. Finally the weight of the fixings wouldn't matter as they are only small components, so heavier metals such as steel can be considered.

The majority of readily avalible fixings are made of stainless steel. If the crane was a permanent structure it would be important to state that stainless steel will corrode faster than aluminium alloy and will therefore need replacing frequently. However as the crane is to be put up then taken down for a job at a time, a quick inspection of the fixings before they are used to check for corrosion and spares to replace fixings that are is all that is needed.

Crane Design

A near complete CAD model of the Crane design. It is an extension of the CAD model already seen. New Features consist of.

• Flexible A frame design, allowing for extra strength but can also fold.
• A hinged beam , allows for easy construction. Although it may weaken the design however Hinged beams have been used on commercial Gantry cranes that can lift up to two tonnes , so it will be strong enough.
• A stablising leg , this indirect leg will only come into play if the crane is at the point of toppling, say if the crane had been put in a precarious position and the main beam was not straight where it may fall over, As an extra safety.

Chosen Material

The chosen material for the crane is Aluminium alloy 7075. It is commonly used in bikes and aerospace as a light metal with high strength and moderate toughness.

It is also important to note: The yield stress has been used to compare the calculated values not the ultimate tensile stress as by the time the stresses had built up so much to reach the ultimate tensile stress the material will have completely plasticly deformed and the crane would be unusable. The yield stress is the point at which the material begins to plasticly and permanently deform which is very undesirable.

For untreated 7075 aluminium:

Specific Density: 2810 Kg/cb.m
Youngs Modulus: 72 Gpa
Yield Stress: 145 x10^6 pa
USD/LB: 0.97

Compared to steel:

Specific Density: 7850 Kg/cb.m
Youngs Modulus: 210Gpa
Yield Stress: 300x10^6 pa
USD/LB: 0.55

It isn't as strong with a Youngs modulus of 75Gpa whereas steel has 200Gpa. However it is much lighter with a specific gravity of 2810 compared with 7850. Its yield strength is 145 x10^6 pa which is below steel but should be more than enough for our crane.

Specific Density: 2640 Kg/cb.m
Youngs Modulus: 68 Gpa
Yield Stress: 60 x10^6 pa
USD/LB: 1.04

Compared with pure aluminium:
It is stronger than pure aluminium, as aluminium's value is 68Gpa but it is the yield stress that is greatly different as pure aluminium is only 60 x10^6 pa. It is slightly heavier by around 200kg/cu.m but this shouldn't make that much difference for the small amounts we'll be using.


To conclude Aluminium alloy 7075 is well suited for our crane as it is light (lighter than steel), it is strong so it should easily be able to withstand the loads and it is reasonably priced. As with all metals prices do fluctuate with the market but at current values it is 0.97 USD/LB.

Crane Design

A final design iteration was drawn up on Solidowrks to give some idea how the final product might look.
Below are two images of the final design:

Once this was complete there was a team meeting. From that meeting it was decided that a 3rd stabilising leg needs to be added. The reason for this was that it’s being used on unlevel ground. The final design does have completely adjustable legs so that the I beam can remain horizontal. However, it was thought that a 3rd leg would be for the just in case situation.

The Final CAD is now being updated to include the 3rd leg.

Gantry crane Design

As the Gantry crane had been adopted here were some ideas before building a Gantry on CAD

. We looked through and decided an A frame would be suitable. This would stop the crane from buckling as well as provide extra support to the joins, relieving them of some of there bending moment. We also adopted a compact approach. The legs could be taken off , the A frame would be collapsible, the whole thing would be adjustable , and a split I beam allowing for easy storage and transportation. A stabilisation leg could be added , in a just in case

scenario if it was to topple at its end , E.G. if the crane was set up so the beam was not straight, it would act like a safety feature. Many of the features seen on this gantry crane are very common with industrial gantry cranes, although un-innovative it does however mean they are effective.

Hinge Design

To make the horizontal beam easier to set up and easier to transport it has been decided to integrate a hinge into the design. The hinge will be located on the underside of the beam and act as a connecting plate as well as a hinge. The hinge will be permanently connected to the beams and only on the top of the I-beam will a connecting plate be used.

Below are preliminary drawings as to how it will work and utilised into the final design. A good material choice for the hinge will be steel as it will be underneath the beam and hence have the load exerted directly on it. Steel is a cheap and convenient way of creating this part to the assembly as it will carry the loads exerted on it with ease as well as being easy to manufacture on a large scale.

Lifting Equipment

To carry the load a hoist must be connected to the beam. A manually controlled hoist is the best idea as this will allow the load to be lifted without the use of electric motors. By using a mechanical winch this excludes the chance of electrical failure and hence the lifting apparatus will not work. Before the hoist can be connected a trolley should be attached to the I-Beam.

Trolley:

The trolley selected should be easy to connect and disconnect from the I-beam as this will decrease the time take to set up the lifting apparatus and also be safer for a single person to connect. With the ability to connect and disconnect at any point the trolley can then freely roll to each end.



The selected trolley has a universal connection underneath allowing any hoist to be connected. The Hoist has a lifting capacity of 1Tonne and a flange width from 65mm to 145mm. This is good for the specified design as the bottom width of the I-beam is 105mm and it is within the briefs lifting requirements. The model number is the HMT10 and the method of connection is shown in the engineering drawing below.



As you can see the trolley is solely connected to the lower section of the I-beam and once the load is lifted it is manually pushed from one end of the gantry to the other.
The cost of this trolley is £60

Hoist:

The method of lifting the load will be done by a ratchet lever hoist. The reason for this method of lifting apparatus is its lifting capabilities and its reliability. The chain lever hoist can be operated by one hand and once lifted it will hold at its location. Rope must be securely fastened around the load and then connected to the hook.



The height of lift from this hoist is 1.5m and its lifting capacity is 1000kg. The hoist itself is constructed from aluminium and only weighs 6.6kg which is within the area of portability.

The device is fully enclosed which promotes safety. The tensile lifting action is countered by an automatically acting load pressure brake. This is the mechanical device which prevents the load from falling once lifted off the ground.
The hooks which are connected to the trolley and load are forged steel which has the highest strength of any method of steel manufacture. This is because these points will be under extreme stresses and forging allows the stresses to be exerted linearly across its internal structure.

The name of the hoist is the Yale ALUMINIUM rachet lever hoist. The model which has a 1000kg lifting capability is priced at £215

Shear Force & Bending Moment Diagrams

Depending on the location of the winch loads and stresses will vary. I have illustrated the shear force and bending moments on the beam.

The beam length will have to extend past the 4 metre distance required to move the load and so 4.2 metres has been selected.

The problem which may arise during practical use of the gantry is at the midpoint. A 4metre beam will not be able to be transported manually and therefore a break will be present in the finished crane. At this point the loads will be exerted on the method of joining and could create loads unsustainable by the joining method.

The weight of the beam has been selected from existing beams. The beams researched are used in portable gantry cranes and are light weight with the sole purpose of manual assembly.

With constant movement of loads across the vertical beam fatigue could be an issue. Fatigue will be cause by continually changing loads on the crane.

It can be seen from the Diagrams shown that higher shear forces and bending moments will be present towards the location of the load. If this continually changes the beam could fail under fatigue stress and so the lifetime of the crane will be dependant on the ability to withstand this factor.

Gantry Crane- Team Meeting

It has been decided that the most practical design would be a gantry crane. This has alleviated the problems of legs, centre of mass problems and counterweights and as such can be made relatively lightly, however the focus for the group is to look at a collapsible main beam which is to be of 4m in length. Different ways of joining the beam and on starting the CAD design.

My design for the collapsible beam is a simple one but it is one that allows for the pulley system of the crane to still movefreely along the beam (on the inside).These can even be made lightweight through use of aluminium and can be stored easier in the back of pick ups.

My proposal for a Gantry crane (pictured left) it has the collapsible beam so it can be taken apart and split into 2x2m sections, an I beam as this gives the best performance for picking up a load directly beneath it. It has fully adjustable legs which can be used on uneven ground, The A shape can be made collapsible also to aid in transportation. Important to note the top of the A shape has a metal plates which strengthen the join at these points. It will also incorporate a manual hoist which will slide along the interior of the I beam. The height of the crane vertically will be no more than 2 m , this allows for long beams to be brought out and moved over small amounts of rubble efficiently. The structure to be able to save weight , will be of high strength aluminium which may be more expensive but its advantages in terms of weight and transportation by hand far outweigh the higher cost. There may be a problem due to the I beam that the crane may have a tendency to tip over sideways , however having enough angle on the legs should remedy this.

Second Moment of area

I did some calculations to work out which shape of beam would be most useful for the gantry design. I looked at three main shapes: circular tubing, square tubing and I beams. I used the same rough dimensions for each shape.

The results were:

Circular tubing with diameter 300mm and thickness 20mm

10.83x10^6 mm^4

This value would be the same for all directions

Square tubing with diameter 300mm and thickness 20mm

24.56x10^6 mm^4

The square tubing is double times stronger than the circular tubing, however this is only at right angles to the faces.

I beam with 300mm height, 20mm thickness and 260mm high post with 30mm thickness.

201x10^6 mm^4

This is 8 times the strength of the square tubing but this is only in the vertical direction.

Rachel: Leg crane designs

After much work trying to work out how to stabilise the crane it was decided by the group to change designs and go with a gantry style crane. These are the ideas about how to stabilise the crane:

Week Meeting

It has been decided that everyone should research on Crane legs and come up with some reasonable ideas that could work as the team wishes to take on Rachels idea and develop it further into a proposed crane, as it fits well with the specification that Sophie Latham has Provided. However if the Leg problem cannot be solved , gantry crane will have to be designed , as this perfectly fits the bill for a emergency crane.

Also at the meeting certain criteria for the main effort of the blog were discussed .

• Why the crane has been designed as it has.
• Mechanical proof of the design.
• Ideas and Innovation.
• Problem solving - Brain storms.

Proposal Specification

Project Outline
The aim of this project is to create a suitable design proposal for a portable crane to be used in disaster relief environments. The crane is to be designed specifically for disaster situations such as earthquakes and tsunamis. These kinds of disaster areas are where there are people trapped under assorted types of rubble such as concrete and steel beams. In these kinds of situations, where construction vehicles are either unavailable or cannot get to the area, the crane would be assembled and used to lift the heavier beams and pieces of rubble.
There are various factors which need to be considered such as quality versus cost and ease of use but the most influential factor, the factor that makes this crane proposal unique, is the extreme environmental conditions the crane will be expected to work in.

Specification Factors
Environmental Conditions

• The heavy rubble and general chaos of the crane site will mean that there is a risk of losing pieces of the crane (if it is transported in various pieces). To reduce this risk, it would be easier to paint the crane an eye-catching colour, preferable a bright colour, which will not only contrast against concrete and steel but will also be seen easier at night.

Costs

• The biggest customer for this crane is going to be countries with high disaster rates. A large number of these countries are third world and ruled by governments with only small budgets available. To deal with this, the crane will need to be cheap enough to be easily purchased by these countries.
• One way to tackle this is to keep the number of manufacturing methods and time used to a minimum. This will reduce man-power needed and the costs to set-up the various manufacturing processes utilised.

Quality

• The quality should be the best available without costing more than we can afford to sell it for.
• This crane will be used to move rubble under which people are trapped; this in itself is a high risk operation, one which doesn’t need the extra hazard of poor quality crane equipment. The crane will likely be pushed to its limits regularly and only with a good quality design and build will it continue to work effectively without more than routine maintenance.

Materials

• The materials used should be strong and hard-wearing whilst also of a reasonable price and quality.
• They will need to be able to function where they will come into contact with high levels of dust and air pollution.
• The materials should be readily available and legal to be used in all countries around the world.
• They should not be hazardous or need special handling requirements. Even any maintenance of the material such painting requirements or special coatings, should be easy to maintain in all countries the crane is sold to and used in.

Ergonomics

• The crane will need to be easy to use, as the rescue workers will be working under extreme pressure and will likely be distracted or not have full concentration whilst operating it.
• No one piece of the crane must exceed the legal weight that any rescue employee can carry safely on their own or with another person. This is for the safety of the rescue workers who will need to be able to carry each piece across rough terrain without damaging themselves in the process. Ideally the weight of each piece should be written on it, in a clear to view place.
• If the crane is to be designed for assembly at the site, the number of various pieces in this assembly should be kept to a minimum. This allows for the user to keep track of the various pieces easier whilst transporting. Another benefit, is the less pieces that need to be assembled, the less assembly instructions the rescue workers need to memorise and carry out every time they use it.
• The crane will need to be easy to maintain. Repair and customer care services will need to be available and all parts should be interchangeable with cheap to purchase spares in case of damage.

Customer Requested Outlines and considerations

• Minimum lifting capability of 1000Kg
• Crane reach of a minimum of 4m from central ‘pick-up’ axis
• To be easily transportable by hand, over rough terrain, for an average distance of 100m. To do this, the crane can either be designed to fold-up into itself or it can be carried onsite in pieces and assembled where it is needed.
• It must be able to either fit into the boot or on the roof rack (2m x 2m) standard Land Rover Rescue vehicle.
• The crane, when assembled on site, must be powered by either hand-crank or power-winch.

Rachel - Table of materials

Below is a table that I have made to compare the young's modulus, yield stress and ultimate stress of different materials which would be considered for the crane.

Material	Specific gravity	Young's Modulus (E)	Proof/Yield Stress	Ultimate. Stress	Price
	kg/cu.m	GPa	x 106Pa	x 106Pa	USD/Kg
Steel C<=0.3%		203
Steel C=>0.3		202
Mild Steel	7850	210	200-400	300-500	0.55
Carbon-moly steels		201
Nickle Steels Ni 2%-9%		192
Cr-Mo steels Cr ½%-2%		205
Cr-Mo steels Cr2 1/4%-3%		210
Chromium Steels Cr 12%,17%,27%		201
Alum Alloy 7075	2810	72	145	276
Aluminium	2640	68.95	30-140	60-140	2.214
Carbon reinforced plastic (50/50 fibre/matrix, unidirectional, along grain)	1700-2000	125-150			Expensive

I have tried to find out prices where possible.

I believe that the crane will have to be made out of a steel of some sort or the more expensive aluminium alloy 7075. This aluminium alloy is normally used for aeroplanes, high performance bikes and mechanical switches but it might have a use within the crane.

It might be possible to have certain parts of the crane which will not be subjected to a high stress to be made out of another material such as aluminium to save on weight.

The table will be updated and reposted if more information becomes available.