Transport Specifics

Exactly how BIG is a Range Rover boot??
Thats the design specification we have to adhere to so I thought i'd explore it. As you can see from the pictures. It's quite alot of space, but not when you think that what we have to build has to be able to lift a tonne, as well as fit in there...

Specific Dimension you ask.. 994 Liters maximum capacity with a full car of people. 2099 with the back seats folded.

That equates to a max length of around 3M with a family of rescuers. Food for thought.

MATERIALS

The materials used to manufacture the crane must be strong and resist at the friction and the pressure due to the load.
We have to look for the density, the tensile strength, the yield strength, and the young's modulus of differente materials to help choose which are suitable.
After research we found that Aluminium and Steel are most common materials that can be used in our purpose because of their advantages.
Aluminium: is the most abundant metal to be found in the nature. It is relatively low weigth. Good resistance to corrosion, Good thermal and electrical conductivity. It can be melted, cast, formaed and machined easely.
Young's modulus, 69 GPa
Yield strength, 55 MPa
Tensile strength, 125 MPa
Density, 2.7 Kg/m^3.
Steel:
Low carbon steel( Mild steel) is the most commonly used, readly welded construction material, and has the following typical mechanical properties:
Density, 7.85 Kg/m^3
Yield strength, 250 MPa
Young's modulus, beteen 190 and 210 GPa
Tensile strength, 280 MPa

Lifting a One Tonne Load

The crane will need to be able to lift a 1000kg load and move it 4m, with no guaranteed source of electricity the only source of power will be manual. For a small group of people, the one tonne load can be easily managed using a pulley system as mentioned under ‘Pulley Design’. Even with a 6 to 1 pulley system a two person team will need to each move the equivalent of 83.3kg by 6m to raise the load just 1m off the ground, that’s almost the same as carrying a person up a single flight of stairs. Using a winch, the turning force generated can be multiplied to reduce the effort a 5th of the original work needed.

The winches available on the market will vary from the design shown so the force that will need to be applied will also vary. The calculations are based in an ideal situation and in reality they will be much greater. Factors such as friction, temperature, humidity, strength of the individuals and the elasticity of the cable will need to be accounted during the second design phase.

Hand Winches

Just a quick look at the types of mechanical winch we will try and incorporate into the crane design.

There are several differing designs for hand winches, but they must all follow this specification:

- normally steel material

- plated with zinc or enamel to prevent corrosion and keep winch smooth

-the gear ration needs to be large enough to enable easy winding of the system and to reduce the amount of turns required to lift an object.

The steel cable graph

Material forces & Implications

Having generated a design for the crane, the issue of material is now at its most relevant as seen above.

I will soon upload the material properties of common materials such as aluminium and steel.

Also the type of rope or line material used is of importance as this ideal needs to be able to withstand over 1000kg whilst in tension. I have done some research on the steel cable design and properties utlising : www.s3i.co.uk.

With varying levels of diameter of cable:

Elastic Stretch = (W x L) / (E x A)

W = Applied Load ( kN )
L = Cable length ( mm )
E = Strand Modulus ( kN/mm2)
A = Area of Cable = (D2 x pi) / 4 (where D= Dia of cable mm)

Typical values for E are:
1x19 = 107.5 kN / mm 2
7x7 = 57.3 kN / mm 2
7x19 = 47.5 kN / mm 2

1x19 Stainless Steel Wire Rope Stronger, with less stretch but also less flexibility than many types of cable. Often used in standing rigging, architectural structural rigging and balustrading. Does not allow for kinks or bends. 7x7 Stainless Steel Wire Rope Less strong but more flexible than 1x19. Used in rigging, balustrade infill and catenary systems. The graph shows typical breaking loads for our hardware compared against conventional 1x19 and Dyform 316 stainless steel cables. It should be noted that stainless steel wire rope and strand will start to distort at around 50% of its breaking load. It is therefore advisable not to load cables to more than 50% of their breaking loads. This is just for steel cables but there are alot more options available for wiring such as aluminium or rope itself eventhough in order to hold the weight, quite a thick rope would have to be used and this may not be suitable for our design as it does need to be able to be transported via range rover! The graph is in the next post.

Pulley Design

Having decided to go with good old man-power for the mechanical design of the crane, the options available to us all involve the use of a pulley design. The aim of the pulley system is to try to reduce the amount of work required to lift a particular load. The aim is to increase the Mechanical Advantage to a point where the load of a tonne that we need to be able to lift, is reduced to a fraction of this so that it can be operated via human power:

Project Manager's weekly blog

Apologies for the being 'missing in action' last week. I had an assessment centre and a few other things to take care of but the PM's blog is finally back. No video today, I couldn't get it to upload properly. After meeting with my chief stress analyst today, we managed to finalise the type of design of the crane we want to go with and as a result of this, have conducted research on the following:

- Pulley Design

- Materials & force implications

- Beam design

- Base Design

These four topics I will upload to the blog shortly after this. The designs for the crane we decided not to put on the blog directly as this could have implications of plagiarism. These specifics will be available in the presentation after Easter.

Stefan Murray

Initial Design

Below is an initial design for the crane. It is loosely based on the engine hoist but with a fixed arm and vertical legs. This should make it more stable in theory and some calculations will be made at a later date to find the idea position and mass of the counter weight.

Gant Chart

Brainstorming

Bellow are some general ideas brought up in the last meeting. The first image shows a guide to the design criteria set out by Emerging Engineering

click to image enlarge

Here are some of the types of cranes and hoisting systems researched. (the size of image and arrows reflect the team's interest towards the design)

click image to enlarge

Summary of meeting 9th March 2010

Attendees
Raj
Ramazani
Onwell
Stefan
Moshin

Meeting Outcome

• All team members issued roles
• Discussed portable cranes on the market and compared prices and practicality

Team Members’ Roles

• Project Manager - Stefan
• Finance Officer - Rama
• Chief Designer - Onwell
• Stress Analyst - Raj
• Materials Specialist - Mohsin
  

Next Meeting

• The next meeting will be on Wednesday 17th March in the Loft.
• Meetings will be held at least once a week.

Project Manager's Weekly Blog

Today we finalised the roles within the group and looked briefly over some current market cranes mainly suitable for the removal of car engine's used in a mechanics workshop/garage.

By this time next week we hope to have atleast a rough costing put in place for the required specification criteria and also at a level of cost suitable enough to interest NGO's and governments but especially NGO's as these types of organisations will already be limited on the amount of funds available.

Stefan Murray (Project Manager)

Summary of meeting 5th March 2010

Attendees
Raj
Rama

Absences
Onwell (reason - interview)
Stefan
Moshin

Meeting Outcome

• The team had set up a blog on http://megroupg.blogspot.com/ which is open to all to view.
• Preferred roles were discussed and chosen by Raj and Rama. The remaining members will have roles by Tuesday.

Team Members’ Roles
So far the roles of team members are:
Rama – Co-ordinator and Finance Officer
Raj – Stress Analyst

Tasks before Next Meeting
Rama

• Email Dr Thomson about blog site and team members’ roles on Tuesday after the meeting*.
• Research cost of similar product on the market
  

Raj

• Research cost of material
• Find possible materials suitable for the job and their properties

Moshin, Onwell and Stefan

• Think of a role you will best fit in the team.

*Next Meeting

• The next meeting will be on Tuesday at 5pm in NG09.
• Members will need to choose roles in the team.

Blog Created

Blog created by Rama and Raj