Project Crane - Group E

Based on the presentations given and heard by our group and other groups, we have been able to access our mistakes both on the building of the crane as a whole and its manufacturing processes. We have decided to take in depth review on our stress analysis, crane balancing and other factor we were unable to complete in due time. On a positive note, we noticed our price range was reasonably good both when sold individually and in bulk based on our 40% wholesale discount. We also left room open to any future developments, adjustments and attachments to our crane to make it suitable for disasters and flood scenarios and in the future, more research would even be made on the production of a more smaller model to do a similar or even bigger job. This would enable the carrying, assembling and dismantling easier which was a major consideration in our quest to achieve and build this model. We expect any feedbacks to be related to us directly and we would get all adjustments sorted out as soon as possible. Thank you.

From the crane analysis, it can be seen that stress is applied on the upper beam and forces are acting from the centre of the beam, the load attached at the end and the weight of the winch. The diagram shows the forces acting on the beam and also modelling the vertical support as just a support and no force coming from there, the force acting vertically from the hydraulic actuator can then be determined in order to know how much force it would take to lift the beam with all the forces acting on it present assuming the weight of the beam is 200kg, the weight of the load is about 1000kg and the weight of the winch is 6kg. All these forces have been multiplied by 9.81 i.e. approximately 10 in order to find their forces due to gravitational effect and the moment has been calculated. The height of lift is also taken into consideration and regardless of the height, a formular has been put in place to determine the lift force.

As a company, we would be looking at making a 35% profit on each crane supplied. If bulk orders were to be placed, we would be able to supply the cranes at a cheaper per unit cost, but will also be able to buy them cheeper.

if a 100 units were ordered; the retail price of each crane would be £585.90
therefore 100 units = £5,859.

these prices are excluding any shipping/duty taxes associated. 35% profit is resonable to both parties as £585.90 is much cheaper than any of the 'competitors' cranes, including a certain crane made from wood?

For countries prone to natural disasters and devolping ecconomies, our product is the best suited for them as the reliability and practicality, are not sacrificed over afordability.

As told in the previous post, the material chosen is Aluminum 7075 due to various properties discussed before but now I will show a brief comparison of it with Steel and other form of aluminum.

Aluminum 7075	Steel
Specific Density 2.81g/cc	Specific Density 7.80g/cc
Price 0.93US$/lb	Price 0.59US$/lb
Ultimate Tensile Stress 275MPa	Ultimate Tensile Stress 558MPa
Young’s Modulus 72GPa	Young’s Modulus 190GPa

As seen from the table, the Young`s Modulus of Steel is very high than Aluminum 7075. But apart from this, it is very much lighter than Steel and due to this, it is suitable to be used in emergency situations.

Aluminum 7075	Aluminum 6061
Specific Density 2.81g/cc	Specific Density 2.75g/cc
Price 0.93US$/lb	Price 0.88US$/lb
Yield Strength 146MPa	Yield Strength 62 MPa
Young’s Modulus 72GPa	Young’s Modulus 65GPa

As seen from the table, the Specific Density of Aluminum 6061 and price is less than Aluminum 7075 but the Yield Strength is very much lower of Aluminum 6061 so one cannot use it for the crane design.

Therefore, due to convenient price, high tensile stress and less density we decided to use Aluminum 7075-T6 as our final material.

Here is a small animation of the crane to show what it would be able to do:



It shows that the main beam can raise and lower from 0 degrees to 80 degrees, making it possible to lift a load over objects; The crane can swivel making it easier to move the lifted load from one place to another; and the legs can move showing the fact that it would be suitable on most surfaces.

Luke - Chief Designer

I have just recieved an email from “Zhangjiagang Deke Co., Ltd.” regarding the bulk order of 100 units. They have stated that i 'should expect around 40% discount' if a 100 units were purchased.

This means that each crane would cost £483.58 as aposed to £805.58. This quote has not been 100% confirmed by the suplier, it is just an approximation given.

This means 100 units = £48,358.20

Chosen by our Chief Desgner, the following hand pump is the most suited for our crane. It is Hydraulic-powered, and is also relativley light at 5.6 kg. This pump is also of rugged construction meaning it is well suited in the type of environments that the crane would be mostly used.

• 12cc Pump + Relief Valve + 3 Litre Reservoir
• Double acting hand pump with lever
• Complete with reservoir
• 12cc per cycle
• Adjustable Relief Valve
• Stainless steel piston rod
• Pump cartridge: all steel construction
• Hi strength aluminum body
• Nickel plated parts
• Low operating effort required
• ISO 9001
• Rugged construction
• Low leakage
• Long life, hard wearing Buna seals are standard
• 3 litre reservoir capacity
• High Strength aluminum and PTFE Nickel plated screws
• Gasket
• Breather plug
• Suction tube fitted
• Weight 5.6kg
• Oil, suitable for 32 grade
• £126.35 exc VAT. (£148.46 incl VAT @ 17.5%)

THE STRENGTH OF THE CONTRACTOR:

- THE CRANE

The crane is made up of 3 major parts: the beam, the vertical support and the base. Our main aim is to manufacture a crane which is capable of carrying load of up to 1000kg and move a distance of 4m on any surface. As we all know, cranes are used in certain situations where there is uneven ground and the base of the crane should be able to support the crane in whatever condition without it falling over. During the manufacture of the crane, we took into consideration its ability to be moved about i.e. carried in vehicle from one location to another hence we have built the crane to be able to dismantle. The crane is dismantled into 6 parts:

1. 4x crane legs

2. 4x crane feet

3. 1x vertical support

4. 1x piston

5. 1x crane beam

6. 1x electrical winch

- ITS FUNCTION

The main function of the crane is to lift loads but in the case of this crane, it has been manufactured to be able to lift loads up to 1000kg. This would enable it to be used in areas such as earthquake disasters and because it can be dismantled, it can be carried from place to place with so much ease. The crane can carry loads high up to an angle of 80˚ and because the vertical support has been built to move around, load can be lifted up and dropped away from the point of removal.

- MATERIALS

The material used to build this crane is the aluminium 7075. The reason behind this for choice of material is for the following reasons: The 7075 alloy is capable of high strength as developed by heat treating. It also has excellent properties at low temperatures, not requiring the corrosion resistance of Clad 7075, Machining capability is good and it is best to machine this alloy in the annealed condition. Other factors have been discussed earlier.

- WHY SHOULD YOU PICK OUR PRODUCT?

As you can see from the design, choice of materials and how the crane is assembled, the following factors put our product ahead of others in the market:

1. Ease of assembly and dismantle

2. Easy to carry around from place to place

3. Able to lift load up to 1000kg

4. Its ability to rotate and pick up and drop loads

5. The height of carriage which accommodate space of wide irregular load

6. Its ability to balance on an uneven ground

7. The choice of aluminium 7075 which would make the crane last long.

It has still not been confirmed whether we are going to use a electric or hand-powered winch. If we do decide to go down the powered route, then a very good candidate is the GP23000. Below are the specifications of this product.

• Capable of 1043kg loading
• 12v DC
  
• weight 6.4kg
  
• Mechanical and Dynamic Brake
• Full-metal Planetary Gear-train
• Freespooling Clutch for Fast Wire Rope Payout
• High Efficiency Low Amp Draw Motor
• Commercial Grade Contactor Pre-mounted and Sealed Against the Elements
• Circuit Breaker Protected
• Durable Handheld Remote Switch on 15' Lead
• Cable Tension Plate
• £188 exc VAT
  

Also the performance of this Winch is listed below.

Line Pull (kg)	Line Speed (m/m)	Motor Amps 12V
0	4.7	8
227	3.8	30
454	3.0	60
680	2.1	90
816	1.8	108
1043	0.5	140

Dimensions;
The problems with using an electric-winch are;

• where will the power come from? battery powered?
• how long will this winch last under ~maximum loading?
• can the cost of this winch be justified? (£188 exc VAT, £220.90 incl VAT )
  
• how long will it take to actually lift the 1000kg weight?

all these questions will have to be discussed before anything regarding this winch is finalised...

I have calculated the beam deflection of our beam.

I have used Mohr`s circle to calculate Maximum Tensile Stress/Shear Force that the crane can go to.

Please keep in mind that this was to be done by Xavier(Stress Analysist) but I and victor had to contribute at the last moment.

Now as the final design is made, we have to decide what sort of electrical winch we will be using. So above is the picture of my idea for an electric winch.

Following are the properties of this electrical winch which are perfect for our crane

· Capable of lifting 1361 kg

· 12v DC supply

· Weight 7.8kg

· 15.2m wire rope / 4.8mm diameter.

· Dimensions (WDH) 323x111x114mm.

· Mechanical safety brake

· Roller fairlead

· Circuit breaker protected

· colour coded & numbered wiring for easier installation

Financial Report

The majority of the components of our product will be made from Aluminium 7075. whilst doing research and gathering information, I was unable to find any companies willing to give quotes for such small manufacturing outputs like this (only ~9 components). Material manufacturers were easily sourced, but production wise i could not find any company willing to produce such few components. On the off chance i found a company ( details below) who were able to not only supply the material, but also give an approximate quote of manufacturing each component. Other interchangeable components ( winch, paint, hand pump ect.) were sourced within the U.K. Each price was given in Dollars and converted to G.B.Pounds.The winch has been included but may vary as its type is yet to be decided.

The pricing is as follows:-

V.T support cap	£16.50
V.T support base	£23.36
V.T support	£66.12
Piston ring	£7.80
Piston	£55.13
Piston rod	£40
Crane legs ( x 4 & incl. horizontal supports)	£65
Beam	£125
Crane base	£35
Red oxide protective paint (2.5 litres)	£19.64
Hand grips (x 4)	£15.96 (£3.99 each)
12V rechargeable electric Winch Hydraulic hand pump	£188 £148.46
Total cost for 1 x Crane	£805.97

The price above includes shipping to mainland U.K to either Liverpool or Portsmouth docks. This quote was obtained from the company “Zhangjiagang Deke Co., Ltd.” Located in Jiangsu, China.This price is for one crane and if a bulk order were required, the individual cost of a crane would dramatically decrease. We are still waiting for an email reply from them, regarding the bulk order price.

Suppliers references

http://deke.en.alibaba.com/

www.paints4u.com

www.gripworks.com

The material chosen for our crane is Aluminum 7075-T6. Although, we searched for many different materials but after group meetings and extensive researches we chose Aluminum 7075 as the final material.

Following are its properties in more detail than in my previous post:

Density	2.81 g/cc
Ultimate Tensile Strength	275MPa
Yield Strength	145MPa
Young’s Modulus	72GPa
Elongation at break	11%,
Poisson Ratio	0.33
Melting Point	600Ċ

Characteristics of Aluminum 7075

· Alloy made mainly from Zinc. Other includes chromium, copper, magnesium e.t.c.

· Light Weight and Smooth surface with dull finish

· High Strength to Weight Ratio, Corrosion Resistant

· Used For High Strength Applications

· Good Ductility

· Used in Aircraft fittings, gears and shafts, fuse parts, meter shafts and gears, missile parts, regulating valve parts, worm gears, keys,, aircraft, aerospace and defense applications

· Also used in bike frames, all terrain vehicle (ATV) e.t.c.

So this is why we chose this as our material for the crane and the next post will contain the stress analysis of the crane.

Please note that we will not be using aluminium 7075 in the screws and bolts used because it is alot expensive to use this alloy in nuts and bolts so to make the crane cheaper, we will be using steel to make nuts,screws and bolts. Although, these can be prone to corrosion but regular inspection can reduce these problem to a great extent.

seen as the height adjustment of the crane will be hand operated, a suitible material to make the adjustment as easy and as comfortable as possible, is required. Typically rubber or a plastic based material is required. Below is a diagram with the differing types available.



The hand-grip to be implemented in our product will be of the type G design. This is one of the most heavy-duty type designs available, and is made from PVC via the dip-moulded process. The main emphasis on this part of the product is style over substance as this will be used in rough terrain. We will require 4 hand-grips per crane, one for each leg.

Here is the CAD of the fully assembled crane:

To add to Shazad's post below; here are screen shots of the CAD of each component.

Vertical Tubular Support Cap:


Outer Piston:


Inner Piston:


Piston Ring:


Crane Foot:


Crane Leg:


Pulley Wheel:


Crane Beam:


Vertical Tubular Support:


VTS Base and Inner Bearing:


Crane Base and Outer Bearing:

In the table below, I have listed the approximate dimensions of each component. Although the dimensions may be altered in the future, the component list is final. The 3-D Computer Aided Designs of each component will be uploaded shortly by the Chief Designer. A number of online quotes from leading material suppliers have been requested and we are just waiting for the reply.

In the meetings, as a group it has been decided that it is more financially viable to source material suppliers overseas. That is why we have been looking into mainly ‘developing’ countries such as China, India as well as the United States. Financial details to follow.