SAFE OPERATION OF BRIDGE CRANE OR GANTRY CRANE

Safe operation Is smooth operation. Avoid lumpy and jerky operation, flying starts, quick reversals and sudden stops.

Do not move a load over a busy work area without giving warning. Watch out for any unexpected movement or obstructions while a load Is moving. Do not carry passengers or allow anyone to Interfere with a load.

Raising and lowering

The driver must use the same control setting to lower the load as needed to raise the load. It the loac needed No 3 setting to be smoothly raised then lower the load with No 3 setting.

Do not use a lower setting to lower a load than was needed to raise the load.

Some cranes have a creep lower speed for accurate positioning while lowering loads.

Some cranes have two hooks from the same crab. Do not change hooks while the first hook Is still under load. Some operations use both hooks such as tipping hot metals ladels and skips.

Starting and stopping

Start all motions slowly and accelerate slowly, step by step, until the fastest speed Is reached. Stop the crane slowly by returning the control to the ‘OFF’ position step by step. Rapid acceleration can cause the contacts to arc and bum.

Chasing the hook

Crane drivers must learn to ‘chase the hook’ (take the swIng out of the load as It Is brought to a halt).

To chase the hook:

1. Stop the movement of the crane before the final stopping place. The load will swing forward.

2. Move the crane quickly to be above the load at the furthest extent of the swing of the load and stop again.

Do not ‘plug’

Do NOT bring the load to a halt by ‘plugging’ the controls. Plugging Is continuously pushing and releasing the control button. This will run the motor too slowly to activate the cooling fan and can burn out the motor and overheat the contacts.

Electrical faults

Electrical faults are the greatest hazards associated with bridge and gantry cranes. If there Is an electrical fault call an electrician.

Do not try to fix an electrical fault, even a blown fuse. It has blown for a reason and must be assessed by an electrician.

It a worker receives an electric shock while holding the hook or load and Is unable to let go:

• Raise the hook Immediately (this will stop the current going to earth through the worker).
• Blow the horn.
• Stay Inside the cabin until someone has turned off the main switch.

Pre-checks prior to turning on the main switch

1. Make sure there are no maintenance signs.

2. Make sure there is no obvious damage to the crane.

3. Check mains switch box for ‘danger tags’.

4. Check the main Isolating switch for ‘danger tags’.

5. Check for any maintenance crew working on the crane.

6. Check that collector wires have not been blown or knocked off the Insulators

They must not have ladders or any other gear resting on them.

7. Check spreaders (container loading gantry cranes) for:

• hydraulic fluid level
• oil leaks
• damage to twistlocks.

8. Check wires and anchorages for defects.

Pre-checks inside the cabin and with the pendant contro

1. Check the WLL (or SWL) stamped on the bridge of the crane.

2. Unlock emergency switch and switch power on.

3. Check control panel lights. (Cabin only)

4. Check for fire extinguisher. (Cabin only)

5. Make sure that you can Identify each of the buttons on the pendant and that they operate freely without sticking.

6. Check that the pendant strainer wire Is properly attached and that the pendant moves freely across the crane without undue force.

7. Drive and then stop the crane a few times In each direction to check the brakes for adjustment and operation of the crane for the job.

8. Test the operation of the working limit switches.

9. Where possible have a full view of the load and the general work area.

10. Make sure that the runways and the general work area are clear of obstructions.

11. If the load hook Is fitted with a safety catch make sure It Is working properly.

12. Make sure that the hoist rope Is free of kinks or obvious broken wires.

13. Make sure that the rope passes easily through all the running sheaves.

14. Check for any obvious mechanical problems.

15. Make sure that the runways and the general work area are clear.

Cross travel motior

The crab must always be brought directly over the load before lifting. If this Is not done, the load wll begin to swing as soon as It Is hoisted.

Do not stand directly beneath the load or allow anyone else to do so.

Long travel motion

The bridge must always be brought directly over the load. It Is not possible to position the hook block directly over the load unless this Is done.

The bridge will always drift after the power has been removed. Cabin controlled cranes have a foot peda brake to stop the bridge. It Is Important to learn to anticipate the amount of ‘drift’ and use the brake as smoothly as possible.

Hoist motion

When the load Is ready to hoist, start hoisting upwards until the slack Is taken out of the slings. Only continue to hoist If the load Is In balance. The person who has slung the load must check the balance of the load for the operator of a cabin controlled crane. Hoist slowly until the load Is clear of the floor and then Increase speed smoothly until the load Is at the required height.

When lowering the load gradually reduce the speed as the load nears Its target.

Reduce to the lowest speed and then ‘Inch’ the load down. Follow the dogger’s directions If you are driving a cabin controlled crane.