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Fitness of use for each part
1. Crane foot extender-Transfers weight from crane leg to the crane foot. Is to made from a 2000 series or 7000series alumium alloy which typically have a compressive stregnth of 400 to 500 mpa and a shear stregnth of 106 to 300mpa. It was calculated to experience a maximum pressure of around 2 to 3 mpa and a maximum load of 5342N. However the leg begins to buckle at 78.25MN so it is in no danger of buckling. Very light, has a of approx mass of 3.7kg.
2. Crane clevis pin – Used to connect height adjustable parts of crane. Is to be made from carbon steel and was calculated to be experienced to a maximum shear force of 13.35mpa which is way below the shear stress of mild carbon steel which is 290mpa.
3. Crane foot – provides contact between the crane and the ground, also it is height adjustable so the crane can remain relatively level on rugged and uneven surfaces. To be made from a 2000 or 7000 series alumium alloy. Calculated maximum compressive pressure experienced is 4 to 5 mpa and and max force is 5342N. Buckles at 3MN. Mass approximately 1.76kg.
4. Rubber crane foot Base – provides friction between ground surface and crane to limit sliding, also protecets the ends of the crane foot from erosion.
5. Crane leg – Transfers weight from crane shoulder to crane foot exetender, splits the weight into three so that each crane foot is experienced to less stress and is height adjustable to make lifting irregular shaped objects on uneven sufaces easier.To be made from a 2000 or 7000 series alumium alloy. Experienced to a maximum compressive force 5324N and pressure of 4 to 5 mpa. Buckles at 50.58MN. Mass approximately 3.25kg.
6. Crane shoulder UB178 – Transfers weight of the boom and load to the rest of the legs, has a tight clearence fit to ensure the boom does not wobble and ensures that the boom is level. To be made from a 2000 or 7000 series alumium alloy. Its calculated that it is expoed to a maximum compressive stress of around 2mpa to 3mpa, experienced to max compressive force of 5342N and buckles at 79.77MN. Mass is approximately 5kg.
7. Crane UB178 boom – Transfers weight from load to the crane legs. This boom is to be created from mild carbon steel. It was calculated that its maximum deflection was around 12mm which is way below the BS 5950 standards, and that the maximum shear force exerted on it it was 10.2mpa which is well below the shear strength for mild carbon steel of 290mpa. The I shape of the beam enables it to be light aswell as strong as the beam only has a mass of 94.77kg which can be easily lifted by four people.
8. Crane washer – Reduces friction and pressure exerted by the crane bolts onto the crane shoulder which prevents damage.
9. Crane nut – Used to fasten the U-bolt to the boom and crane shoulder. (size will be between M12 and M36).
10. Crane U-bolt - connects the crane shoulder to the boom and also stops the crane from toppling due to horizontal forces. (size will be between M12 and M36).It was calulated this bolt is experienced to a maximun shear stress of 92mpa (for M12 bolt) which again is way below the shear stress of mild carbon steel which is 290mpa.
Accessories
1. 6 Spike rubber foot bases for soft ground and 6 grooved foot bases for wet conditions.
2. Spanner for tightening the bolts (size will be between M12 and M36).
Construction of the crane
Resources needed: 4 people, WD 40 (optional), hard hat, steel toe cap boots, thick gloves, whatever else is needed for safe working conditions.
fig.1
Step1- Push the the rubber foot bases onto the crane feet.
fig.2
Step 2- Slide the crane foot into the crane foot extender so that 2 of their holes are cocentric, then insert 2 clevis pin into the holes. Repeat for all six feet.
fig.3
Step 3- slide three crane feet into onto a crane leg, make sure the holes are cocentric and insert 2 clevis pins. Repeat for other leg.fig.4
Step 4 – Spray the WD40 into the crane shoulder ‘pocket’ (i.e. where the beam will be inserted).Next lie the crane shoulder sideways on the floor and slide the beam into the pocket until the holes on the beam are cocentric with the crane shoulder holes. Insert the U-bolt and slide a washer on each thread. Finally tighten the bolt using the spanner provided. Repeat for other side.fig.5
Step 5 – Stand the crane legs up. Then 3 people should pick the crane boom and shoulder up off the floor, the fourth person should the guide the crane shoulder down onto the crane leg. Once the holes are cocentric 2 clevis pins should be inserted. Repeat for other side.
Maintenance
- The crane is to be dismantled when not in use.
- The crane should not be stored/left for long periods of time with a load connected to it, this may cause the components to bend due to creep.
- The crane components should be stored in a dry cool place to minimise oxidation of the boom and other steel components i.e. bolts.
- Paint may be added to the crane to reduce erosion and rusting.
- Lubricating the holes for clevis pins and u-bolts will ensure the pins and bolts have a longer life.
- Do not operate in wet conditions for prolonged periods of time.
- Clean all the components after use.
- READ INTRUCTIONS CAREFULLY BEFORE USE.
- When constructing the crane always wear protective gear such as hard hats, steel toe cap boots etc.
- The crane should be constructed by 4 people minimum.
- The crane should not be operated on a incline of more than 10 degrees.
- The crane should only be operated in areas where the user can remain a safe distance away.
- The crane should never be operated on unstable surfaces or in icy condtions.
- All safety labels on the crane should be kept legible and in sight. If they become damaged contact the manufacterer for new ones free of charge.
- The crane should never lift items in excess of 1000kg.
- The load should be applied evenly and slowly. never jerk the load or swing it from side to side.
- All equipment should be checked for cracks and impairment before construction. If found the crane is not to be used.
- Never leave a load unattended.
- Never use the crane to lift people or animals.
- Centre the hoist over the load before lifting.
INSTRUCTION MANUAL FOR GANTRY CRANE
To construct the crane in a safe way yo must:
1) Construct the legs
2) Place on secure ground
3) Lift beam into shoulders
4) Make sure beam is level
Construct Legs
1. First take the crane foot (part 3) and place the required rubber base (part 4) on the end
2. Take the crane foot extender (part 1) and attach it to the crane foot
3. Take two crane clevis pins (part 2) and secure the crane foot to the crane foot extender
repeat steps 1-3 3 times
4. Take the crane leg (part 5) and attach the three crane feet to the crane leg
5. Take 6 clevis pins and attach the 3 crane feet to the crane leg
6. Take the crane shoulder (part 6) and attach it to the crane leg
7. Take 2 clevis pins and secure the crane shoulder to the crane leg.
8. Adjust the position of the three feet so that the leg is perpendicular to the ground
repeat steps 1-8
Place on Secure Ground
The crane must be placed on solid ground and the leg should be perpendicular to the ground
WARNING: If the leg is not straight and not stable you risk the crane falling over. This is a health risk to anyone working or near the crane. Damage could also be done to the crane and could cause it to be permanently useless.
Lift Beam into Shoulder
Once both legs are place securely on the ground surface the beam can then be lifted into the shoulder.
WARNING: The beam is a heavy component and to be lifted safely at least 4 people must be present so as not to cause the users of the crane bodily harm. This ensures also that the beam has less chance of being dropped and being damaged.
If the beam does not go into the shoulders straight away shift the legs until the beam and shoulder match correctly.
Making sure Beam is Level
The beam has to be roughly parallel with the ground for the winch to work properly. To do this you must:
1. Make sure that the weight of the beam is being partly supported by the other workers
2. Look at the spirit level which is on the beam itself
3. By the reading observed adjust the height of each leg so the spirit level reads flat.
