Lifting a Precast Cover With the Bucket
You need to place a 450 kg precast concrete cover onto a chamber 3 m from the machine. The excavator has a lifting eye welded to the bucket and a rated capacity plate showing 1,200 kg at 3 m radius in the current configuration. The ground is level compacted fill. A slinger has attached a two-leg chain sling at 60° included angle (each leg rated 2 t) to the lifting eye. The load is currently on the ground 3 m from the machine, and the bucket is at 3.2 m radius when the load is just clear of the ground. The wind is gusting and the load begins to swing.
1. Is this lift within capacity, and what must you check before lifting?
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The rated capacity at 3 m is 1,200 kg and the load is 450 kg, so there is margin - but the actual radius at lift is 3.2 m, so you must use the capacity at the actual radius, not the nominal 3 m. Check the load chart for 3.2 m and confirm the margin. Also check: the lifting eye is rated and in good condition; the sling is rated for the load and the configuration (two-leg at 60° included angle gives a leg factor - each leg carries load/(2×cos30°) ≈ 260 kg, well within 2 t, but check the angle and the sling's SWL at that angle); the ground is level and firm; the load is balanced and the slinger is clear; and the machine is on level ground with the bucket/boom in the correct lifting configuration. The lift must be planned and the load controlled with a tag line if it swings.
2. The load starts to swing in the gusting wind. What do you do, and why is 'just lower it quickly' wrong?
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Stop the lift, hold the load steady or lower it slowly and deliberately to the ground under control, and do not attempt to catch or chase the swing with rapid boom/bucket movements. Rapid lowering or slewing can induce further swing and shock-load the sling and lifting eye, and can put the slinger in the danger zone. The correct response is to lower gently, wait for the gust to pass, and if the wind is beyond the safe limit for the load's sail area, abandon the lift and resecure the load. A swinging load also changes the effective radius and can exceed the capacity at the actual radius.
3. What would make this lift a 'lift plan required' operation rather than a routine lift, and what controls apply?
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It becomes a planned lift where the load is near capacity at the actual radius, where the load is difficult to control (wind, sail area, offset centre of gravity), where people are near the load, or where the machine is not on level firm ground. Controls: a written lift plan, a competent appointed person, rated lifting accessories with current examination, a controlled exclusion zone under and around the load, tag lines, agreed signals, and a check that the machine's rated capacity at the actual radius covers the load plus any dynamic factor. The bucket lifting eye is only acceptable if it is a designed, rated point - not an ad hoc weld.