Experience

The overall design of our crane was simple and could sustain in the adverse conditions as mentioned in the tender. I personally feel, we could have designed it better, if we were given little bit more time. I apologise for not updating the blog on time. Unfortunately, the main reason behind this was my injury, because of what I was on bed for more than 4 weeks. As I did not have internet access, I could not do any work while I was on bed. After four weeks, I could walk with crutches, but was left behind in other modules too. As I feared to do badly in other modules too, I tried to put my efforts to catch up on everything I missed. Even though, I had short span of time to work towards this project, it was a good experience to use the available information around us and virtually manufacturing something very important from scratch.

Conclusion

Overall I am not pleased with the outcome of this project; it could have been a lot better. The lack of commitment of certain individuals caused a major setback to the project. The quality of the crane could have been improved in many aspects. This was a disappointing project and if I were to do it again, I would do things a lot differently.

Costs

As according to the calculations, the total volume of HSLA steel used is 18.084*10^(-3) m^3 and cost of 1 m^3 is £ 35277.77.

So, therefore the cost of the total HSLA steel to be used is = 35277.77*18.084*10^(-3) GBP

= £637.96

Cost of the manufacturing of special I-Beam = £100

Cost of 16 nuts and 16 bolts is as follows;

Cost of A2 stainless steel M12*110mm bolts = £ 19.50

Cost of A2 stainless steel M12 hex nuts = £ 2.70

Cost of chain hoist = £ 150.49

Cost of rollers = £ 48.69

Cost of rubber sphere = £20.99

The total cost of crane comes out to be £ 980.33. As this is the cost of single K-crane, the cost per crane can be brought down depending on the number of cranes ordered.

The selling price of this crane is £1349.99 giving us the profit of approximately £370 per crane. Assuming, if we get the order for 100 cranes, we can easily make profit more than £37,000.

Total Volume of Steel Used

1.) Volume of the top sheet = 5*0.08*0.005m^3 = 0.002 m^3
Volume of the both sheets = 2 * 0.002 m^3 = 0.004 m^3

Volume of vertical sheet = 10*10^(-3)*190*10^(-3)*5 = 0.0095m^3
Total volume of the top beam = Sum of the volumes two parallel sheets and vertical sheet
= (9.5+4)*10^(-3) m^3 = 13.5 * 10^(-3) m^3

2.) Now, In this part we would calculate the volume of the rectangular bars,
Height of the bar = 1.06 m
Breadth of the bar = 50 mm
width of the bar = 50 mm
, therefore the volume of this bar = 1.06*0.05*0.05 m^3
= 2.65 * 10^(-3) m^3
Since this bar is hollow from inside, we would calculate the volume of unoccupied space
= 1.06*0.04*0.04 m^3 ( the thickness is 5 mm)
= 1.69*10^(-3) m^3

The original volume occupied by HSLA steel = (2.65-1.69)*10^(-3) m^3
= 0.96*10^(-3) m^3
As the total no. of bars used in this gantry crane is 2, so multiplying the result by 2, we get
= 2*0.96 *10^(-3) m^3 = 1.92*10^(-3)m^3


3.) Here we will determine the amount of material used i.e. the volume of the four hollow legs used in this crane.
Height of the rectangular bar = 0.74m
Width of the bar = 50mm
breadth of the bar = 50mm
Volume = 0.74*0.05*0.05 m^3
= 1.85 * 10^(-3) m^3
Since the thickness of the steel is 5 mm, therefore in this case the breadth and width becomes 40 mm.
The volume of the space with these dimension = 0.74*0.04*0.04m^3
= 1.184*10^(-3) m^3
The volume of the steel used in this bar = (1.85-1.184)*10^(-3) m^3
= 0.666*10^(-3) m^3
Now, the number of these bar legs used = 4
The total volume of the HSLA steel used = 4*0.666*10(-3)m^3
=2.664*10^(-3) m^3

4.) Volume of the spheres used = 4*4/3*3.14*((0.15/2)^3) m^3
= 4*1.767*10^(-3) m^3
= 7.068*10^(-3) m^3
The material used for these spherical balls is volcanic rubber which would give the crane extra stability on uneven ground.

According to these calculations, the total volume of the HSLA steel used = 18.084*10^(-3) m^3

Main Beam Final Calculations

These calculations show the final dimensions for the main beam cross section that we settled on. The I value is finalised and the maximum stress and maximum deflection are calculated to be comfortably below the threshold that we decided.

Weight of Main Beam

An estimated weight of 105.3kg is established for our main beam. We consider this to be a weight that can be carried by multiple people over 100m and carried by vehicle.

A further consideration is that the ends of the beam could be made smaller as shown in the diagram at the top of the picture. As most of the stress and weight is centred in the middle of the beam, the ends wouldn't need to be as thick and weight of the beam could be minimised in this way.

Main Beam Further Calculations

These calculations provide different values of I by using different dimensions for the cross-section.

Lifting Chain

Lifting chain is designed for use with hoists, cranes, winches, and other material handling equipment. It is also used in rigging slings and for lashing. There are two standard grades for lifting chain: grade 80 lifting chain and grade 100 lifting chain
We will be using grade 100 lifting chain which is made of alloyed steel and is hardened and tempered for superior durability and fatigue resistance.Grade 100 lifting chain is made of Herc-Alloy 800, a heat-treated alloy with very high strength. 'When working with lifting chain, working load limit and rated capacity vary with the angle of use and the number of lifting chain used in a sling. For example, a single 5.5 mm lifting chain may be rated for 2100 lbs. at 90 degrees. A double 5.5 mm lifting chain may be rated for 60, 45, or 30 degree use with working loads of 3600, 3000, and 2100 lbs. respectively.'

Nuts and Bolts

The nuts and bolts which we will use in the manufacturing of our crane will be made of stainless steel. The nuts as well as the bolts will be coated with zinc to prevent corrosion.Stainless steel is a type of metal alloy. The components of stainless steel are iron, chromium, carbon, nickel, molybdenum and small quantities of other metals. These components are present in varied proportion in different varieties of steels. In stainless steel, the chromium content should not be less than 11 percent. The high content of chromium present in stainless steel is responsible for corrosion resistant property. In order to achieve higher resistance to corrosion nickel is added. Iron is the primary component of steel but it resists oxidation because the chromium present in the steel reacts with oxygen to form chromium oxide. It adheres to the surface of the stainless steel in the form of a tough, passive coating. In case the surface of this layer is damaged due to some chemical or mechanical effect, the chromium oxide formed, is capable of mending the damage. The strength and toughness of steel is because of the carbon present in it. With the increase in the carbon content the toughness of steel also increases

Reasons For Using HSLA Steel

Reason for Using HSLA

:HSLA steels contain additions such as zirconium, calcium, or rare-earth elements for sulfide-inclusion shape control.

: Additions of elements such as copper, silicon, nickel, chromium, and phosphorus can improve atmospheric corrosion resistance of these alloys

: Grades known as "improved-formability" HSLA steels (sheet-steel grades designated ASTM A715, and plates designated ASTM A656) have yield strengths up to 80,000 psi, yet cost only about 24% more than a typical 34,000-psi plain-carbon steel

: High-strength low-alloy (HSLA) steel is a type of alloy steel that provides better mechanical properties or greater resistance to corrosion than carbon steel

: HSLA steels are usually 20 to 30% lighter than a carbon steel with the same strength.

: HSLA steels are also more resistant to rust than most carbon steels, due to their lack of pearlite – the fine layers of ferrite (almost pure iron) and cementite in pearlite

Final Material Used

Final Material

We will be using HSLA(High Strength low-alloy Steel) to manufacture our crane. It provides better mechanical properties or more resistance to corrosion as compared to carbon steel. HSLA steels vary from other steels as they are made to meet a specific mechanical property and not to a specific chemical property. It has small amount of alloying elements like copper,nickel , nitrogen, vanadium, chromium, molybdenum, titanium, calcium, rare earth elements . These elements are intended to alter the microstructure of carbon steels, which is usually a ferrite-pearlite aggregate, to produce a very fine dispersion of alloycarbides in an almost pure ferrite matrix. This eliminates the toughness-reducing effect of a pearlitic volume fraction, yet maintains and increases the material's strength by refining the grain size, which in the case of ferrite increases yield strength by 50% for every halving of the mean grain diameter. The yield strength of HSLA steel lies between 250-590 megapascal. HSLA steels require around 30% more power to form as compared to carbon steels because of its great strength.
To increase corrosion resistance elements like Copper, silicon, chromium, nickel and phosphorus are added. Increased formability is needed because HSLA steels have directionally sensitive properties. Impact Strength and formability vary significantly when tested transversely and longitudinally to the grain. HSLA steels when treated for sulphide shape control have directional characteristic reduced substantially.
HSLA steels are lighter as compared to carbon steel with same strength and due to fine layer of ferrite (almost pure iron) and cementite in pearlite HSLA steels are more resistant to rust than most carbon steel

Raw Materials Required

Raw Materials:

The most important material used to manufacture cranes is steel, which is an alloy of iron mixed with small amount of carbon to increase its hardness. Carbon steel is used for structures that do not require very high strength. The most important factor which determines the property of carbon is the amount of carbon present in it, which may range from 0.015% to more than 0.5%
HSLA steels are used for the manufacturing of cranes that are designed to lift very heavy objects. HSLA steel contains low levels of carbon and small amount of other elements such chromium, nickel, vanadium, titanium and niobium. Hsla steels resist atmospheric corrosion and are better suited to welding than carbon steel
Wide varieties of other materials are also used in the manufacturing of cranes. Natural or Synthetic rubbers are used to make tires for cranes which are mobile. Electrical components may include semiconductors such as germanium and silicon and copper wires for electrical circuits.

Final Design

Gantry Crane Design

Above is a drawing of the final design. The design is based on a workshop gantry crane and it is very simple in design as this was done deliberately to minimise the effort and confusion when setting up the crane and when using it. Therefore the crane comes only in three pieces one I beam and two struts.
I decided that a mechanical winch and a mechanical hoist would be the best option again to make things easier for the user. The winch will slide into the I-beam whilst setting up it will have wheels which will move the crane in the X direction. A diagram of the winch on the I-beam can be seen below:

The I-beam will be bolted onto the I-beam via 8 bolts these will be sufficient enough to hold the parts together. These will be the only parts on the crane that will be bolted together.
See below:

The crane will rest on rubber spheres that are flat at the bottom; it will be placed on rough ground so the spheres will fit into the ground to provide extra stability. Initially we thought about adding wheels but these would have been unnecessary and may have reduced the stability of the crane. The design of the crane is actually quite durable, there are no wheels or no attached bits to the crane therefore one does not have to worry about things breaking.

The crane parts can easily be transported by a small helicopter and taken to the site. It will take a total of 8 people to carry the crane parts; 3 people for the beam two people for each strut and one person to carry the winch and hoist. Although the beam itself will not be able to fit inside a land rover a separate carrier compartment can be made where the crane can be hauled by the 4X4.

Below are drawings illustrating the dimensions of the crane:
















(Supporting Sphere)













I-Beam (The I-beam will be 5M in length)





















(Strut Side View)











Square beam (struts) this is a cross section of the struts.

(support and bolting plate) this is where the struts bolt onto the I-Beam. The triangle piece is there to provide support to the beam.

Initial Beam Design

Build up to final design

Once we analysed the various designs we realised that our designs were getting to complicated and we were missing the simplicity of the requirements in the brief. Thus we decided to focus on a gantry crane and designed a crane accordingly.

Here we analysed the gantry crane and how to change it. We also discussed the kind of beam that we would use.

Here we came to our Final design idea. We decided to keep the design of the crane as simple as possible. We also decided to use an I-Beam.

Initial Designs

These designs were sketched and was given to our chief designer for final selection.I had come up with these ideas before the vacation and had given them to Varinder and Richard for better understanding .

Initial Crane Designs

These initial crane designs are extremely crude but give food for thought and upon analysis, although some material is immediately discarded, some good core ideas surface.

Design 1


The first design is similar to a JCB digger.

Advantages:

• The use of 4 heavy duty wheels help it to move through rough terrain without being assembled and dissassembled constantly.
• A pivot above the base allows the boom to swivel to discard of picked up material.
• A scoop like connection at the front can move gravel and multiple smaller objects with ease.
• A hydraulic system can be utilised easily at the touch of a button.

Disadvantages:

• Using wheels in this manner may leave the crane unstable and likely to topple upon picking up large weights.
• The scoop would be useless when confronted with a large solid beam.
• Many parts of this design would be extremely heavy when disassembled, making carrying the individual parts impossible.

Design 2

Advantages:

• A strong sturdy base would give a good platform for the crane to operate.
• A hydraulic system could lift the boom up and down quickly.
• The vaccuum operated suction device would be able to attach to most objects.

Disadvantages:

• The crane is completely immobile.
• There is no means to transfer it's load apart from vertically, work would have to be done and then the load would be set back down again.
• If such a vacuum system was available, it would be likely to be very expensive.

Design 3

Advantages:

• 'Spider' legs would provide good support on rough terrain and could easily be attached.
• A strong winch mechanism can be attached easily onto the framework to provide a good lifting force.
• The holding mechanism would be able to grasp objects quickly with strength.

Disadvantages:

• The crane is stationary which is unpractical.
• Upon grasping a load, the 'claw' mechanism would not be very efficient in keeping a grip on it.
• Another system such as a pivot would be useful to move the load out of the way.

Here are my initial designs that I think would do the required job in rough conditions. These designs are brought up in our 2nd meeting on 10/03/10. My first design for the crane is very simple, it lifts the load with the help of winch and pulley and then the the crane as a whole can be moved to different place. Since the crane, we need to design is for rough and uneven ground, this design was not good enough.
My second design is inspired from gantry cranes. This would lift the load from one end of the crane and move to the other end.
The next design is inspired from military tanks. As they are highly stable on uneven grounds, so the base of this crane is quite similar to that of military tank. The belt used on tank's tyre will be used for these cranes in manufacturing.
The fourth design is modification of the last design. The principle of this crane is same as that of the third design. The only difference is that it has got bending legs. The reason to include these legs is make the movement of load easy and effecting.
The final design I have here is influenced from the concept of sky mars crane.

Initial Designs

Basic crane




















Crane with two arms




















Transport/tyres

Brainstorming Design Ideas

Gantry Cranes

Gantry crane is a type of crane that lifts load by hoist ropes, which is fixed in a trolley that moves freely on pair of rails under a beam. These cranes have wheels on the foot of the crane for mobility purposes. Some of the gantry cranes are fixed and move the railway cargo.

Small gantry cranes can be used in garages for lifting the automobiles engine out of vehicles. It is mostly used in demanding circumstances. These cranes are also used as an alternative to construction cranes. These cranes are highly advantageous to use in areas which have restricted access or are impassable. The reason behind this is their structure, their light weight and easy to use.

Some of the big gantry cranes that are used in shipping industry to move ship engines are capable of lifting 840 tonnes, had height of 70 meters and had lifting capacity of 1600 tonnes.

Various Cranes

As the crane is to be placed in a disaster area, there are various types of crane which we feel will be suitable for this environment.

Below are a few examples:

Mobile crane

A mobile crane can be very basic. It could be a full sized crane, or even a crane with only a telescopic boom on a platform. Crane's are mschine's often used for lifting heavy objects. A standard crane is fitted with a wire rope drum, chains, and a control panel. Another type of a crane can be one with the additonal flexibility to access sites and reach equipment that are otherwise difficult to access. These are known as mobile crane's.

There are six different types of mobile crane:
1. Truck Crane
2. Side Lift Crane
3. All Terrain Crane
4. Crawler Crane
5. Railroad Crane
6. Gantry Cranes

All cranes must be operated by trained staff. Depending on the size of the load and the location of the crane, a spotter may be required to ensure that the load is properly installed.

Truck Crane


Most common type of crane which people are most familiar with, is the truck crane. This is where the actual crane is mounted to the body of a truck. The advantage of a Truck crane is that it is able to travel on main roads and highways. This additional flexibility makes it possible to transport large loads and access a wide range of locations.

Side lift crane

(Click to see enlarged picture)
A side lift crane is another type of mobile crane able to transport materials and hoist large containers. Very large containers are lifted using a pair of side lift cranes. The added benefit of this mobile crane is that it can be used to lift a container from the ground, providing extra flexibility.

All Terrain Crane

All terrain cranes can travel on regular roads as well as over rough terrain. This type of mobile crane has all wheel and crab steering for extra flexibility. The ability to cover different terrains in the same equipment is very important when working on new construction and development projects.

Crawler crane

(Click to see enlarged picture)
The main advantage of a crawler crane is the ability to quickly lift items with very little set up. That can be very helpful as there is very little time in a disaster area and a quick set up crane would be ideal. Crawler crane allows users to avoid the process to stabilize the crane as the size and design of the crane is placed on the undercarriage, along with the tracks. The advantage of a Crawler Crane is that the the sheer weight of the crane, along with the longer contact with the ground eliminates this requirement for all but the heaviest loads.

Gantry Crane

(Click to see enlarged picture)
A gantry crane is a type of overhead crane. With a gantry crane, the supports holding the crane up are fixed in location. They cannot move, and therefore the crane cannot move. For this reason, everything that the crane is going to lift must be brought to the crane. The supports form a large rectangular frame upon which the crane can move forward and back, and left and right. Anything that can be reached by the gantry crane is referred to as being in its operating area.
Gantry cranes are very common in factories, where they are used to move things along the factory floor as the product is slowly assembled. For instance, if one is building a large metal piece of equipment, the metal parts may arrive on a truck. The truck will park within the operating area of the gantry crane, and the gantry crane can then be used to unload the parts. The gantry crane may also be used to move the parts around, typically along the assembly line as the components are assembled. Once the item is complete, the gantry crane can be used to load the finished part back onto a truck so that it can be removed from the factory.

Tower crane

The tower crane is a modern form of balance crane. Fixed to the ground (and sometimes attached to the sides of structures as well), tower cranes often give the best combination of height and lifting capacity and are used in the construction of tall buildings.
The jib and counter-jib are mounted to the turntable, where the slewing bearing and slewing machinery are located. The counter-jib carries a counterweight, usually of concrete blocks, while the jib suspends the load from the trolley. The Hoist motor and transmissions are located on the mechanical deck on the counter-jib, while the trolley motor is located on the jib. The crane operator either sits in a cabin at the top of the tower or controls the crane by radio remote control from the ground. In the first case the operator's cabin is most usually located at the top of the tower attached to the turntable, but can be mounted on the jib, or partway down the tower. The lifting hook is operated by using electric motors to manipulate wire rope cables through a system of sheaves.
Below is a labelled diagram of a tower crane:


To get first hand experience for cranes I went out and looked at how they work first hand. There is a development happening in the West Bromwich area. A tower crane was being used and so I went and took a few pictures and observed how the crane is controlled and also operated.






(Photos taken from a mobile phone)

There is also a development happening at the Aston University campus therefore I also visited this for further inspiration.


The above picture give me an indication of what type of wheels we should put on the design, as the crane will not be transported to the site on flat ground.

A Brief History of Cranes

In a bid to learn more, and design the most efficient crane, I've attempted to put myself in the position of the original crane designers by studying the history of them.

Power Sources


The very first cranes were invented for use in construction much like those today. However, they were on a much smaller scale and were powered only by men or animals. These were eventually developed to include the treadmill where multiple men or animals could drive the winch together.


In the 18th century, steam engines were invented and used to power cranes. In more modern times, the development of combustion engines, electric motors and hydraulic systems give cranes the power to lift colossal weights.


Specific Systems


The compound pulley system was first mentioned in aristotles writings and later on, crane technology flourished during the roman empire.

The most basic type of crane used was the "trispastos".

This incorporated a jib, a winch, a rope and a block which used 3 pulleys.

The name trispastos indicates that the system uses a 3 pulley block.


Other systems include the "pentaspastos", a system with 5 pulleys.

The largest type was called the "polypastos", a system using many pulleys which could lift over 3 tons per person operating it.

Diagrams courtesy of Eric Gaba.

What is a Crane

A crane can be described as a machine which is capable of lowering and lifting heavy objects and also moving them horizontally the difference between a crane and hoist is that hoist can lift objects vertically but cant move them horizontally. The word crane is taken from the fact that these machines have a shape similar to that of the tall, long-necked bird of the same name.
As early as the first century, cranes were built which were powered by animals or human beings .these types of cranes had a boom connected to a rotating base. It had a treadmill which powered the drum around the rope was wounded. The rope was attached to the pully at the top of the boom and to a hook or holder which lifts the load or weight.
A great advancement was made in crane design during Middle Ages when an horizontal arm called the ‘jib’was attached to the boom in a way which allowed it to pivot, allowing for an increased range of motion
Cranes continued to be operated by human being until middle of the 19th century when steam engines were developed. Electric motors and internal combustion engines were used to power cranes . During the first half of twenth century cranes were developed is such a way that it had tall slender towers with the boom and the operator on the top of the tower. During the 1950s, the availability of stronger steels, combined with an increased demand for taller buildings, led to the development of cranes with very long booms attached to small trucks, or to crawlers with caterpillar treads. Mobile cranes and tower cranes of many different kinds are used extensively in construction sites around the world.

Introduction

The aim of Our project is to build a portable crane which is capable of lifting loads of up to 1000kg and moving loads by at least 4m. Keeping in mind the recent earthquakes which has caused a lot of problems in various countries ,designing a portable crane to lift and clear loose materials and heavy beams is indeed a good innovative idea. Our aim is to design and manufacture a crane which has great utility value and is attractive to NGO and Governmental organisations who wish to provide assistance to the disaster prone areas.
The crane will be especially designed to clear loose materials and heavy rubble at calamity prone areas, keeping in mind natural calamities like earthquakes.
The design of the crane will be that it portable and can be taken to the place required by a small team to clear Debris, where earthmoving and big cranes are not able to reach due to physical barriers or encroachments.



Rohit Singh

2nd Meeting

10/03/2010

We had our second meeting today, where we all discussed various designs for the crane. The main focus was on the designs as we thought if we confirm 1 design which is feasible in the market and there is a gap for, we can then start research in our specific individual roles. We all decided that all of us as individuals are going to come up with 5 designs each and then in our next meeting look at the advantages and disadvantages of each design, and then once confirmed by the chief designer (Varinder Singh), choose 1 main design to move forward with. Our next meeting has been scheduled for the 12/03/2010 where we are going to exchange designs and ideas.

Soon there will be some posts/pictures of all the different designs we all came up with.

Below is a Gantt chart we created to keep a track of our deadlines.



Harind

Contact Details

Harind Singh (singhh11@aston.ac.uk)
Richard Smith (smithr4@aston.ac.uk)
Rohit Singh (singhr8@aston.ac.uk)
Varinder Singh (singhv1@aston.ac.uk)
Sampan Singh (singhs16@aston.ac.uk)

Purpose Of The Project

The main purpose for this project is for us as a group to design a small portable crane to help remove rubble in a disaster such as an earthquake. The main reason for that is, that on many occasions there have been natural disasters (e.g. earthquakes) where large numbers of people end up being trapped under the debris and rubble of the buildings.

Harind, Varinder

Project Launch

09/03/2010

Day of our first meet.

Today, we as a group met for the first time. We are all excited about the brief and we looking forward to work on this project as a group.

These are the various roles of the members in the group:

Project manager: Harind Singh
Finance Officer: Sampan Singh
Chief Designer: Varinder Singh
Stress Analyst: Richard Smith
Materials Specialist: Rohit Singh

We all met up and assigned roles to each other. The initial meeting was to break the ice between the group and get to know each other. Various targets were set and initial research was done.
Harind, Varinder