Pre-operation inspection of crawler crane and accessories
Pre-operation inspection of crawler crane and accessories
This domain tests whether you can prove a crawler crane is fit for the shift before the engine starts: structural, rope, safety-device and fluid checks, and the judgement to reject a machine.
What the exam expects
- Structure: track shoes, grousers, links, pins, sprocket and idler wear, track frame and carbody cracks, boom chords and lacings, boom foot pins and retainers, pendant (boom suspension) ropes, boom stop, and sheave condition (flange wear, gauge, free rotation, cracked webs).
- Wire rope: inspect the full length, including boom-tip sheaves and the drum wraps. Typical removal criteria: 6 or more randomly distributed broken wires in one lay, 3 or more in one strand in one lay, kinks, bird-caging, core protrusion, diameter reduction, severe corrosion or heat damage. Replace a hook with a missing latch or an opened throat.
- Safety devices: anti-two-block weight and alarm, rated capacity limiter/load moment indicator and its calibration sticker, boom angle indicator, level indicator, horn, swing alarm, house lock.
- Fluids and function: engine oil, coolant, hydraulic level and leaks, filter indicators, battery - then a no-load function test of hoist, boom, swing, travel and brakes.
Worked example
A 22 mm 6x37 rope shows 7 broken wires scattered along one lay, plus 4 broken wires in a single strand of the same lay. Both limits are exceeded: 7 > 6 random, and 4 > 3 in one strand. Reject the rope, tag the crane out of service, and record the rope position and date in the logbook.
Traps
Counting broken wires over the whole rope instead of within one lay; inspecting only the visible falls; accepting a "minor" LMI fault; treating crawler cranes as if they had outriggers; skipping the function test because the machine "ran fine yesterday".