Mobile Cranes and Boom Maintenance

Telescoping Booms

• Mobile telescoping cranes use a boom attached via boom pins, operated by hydraulic rams.
• Inspect upper/lower boom pins and boom derrick ram attachment pins to prevent boom collapse.
• Ensure locking pins are secured; loose pins can lead to accidents.
• Check hydraulic connections for leaks; observe derrick pistons for signs of oil leakage.
• Test the boom's movement under load to verify the presence of leaks.

Telescoping Boom Flexing

• Modern booms can flex significantly when fully extended and loaded; this is normal.
• A downward bend while not under load may indicate wear pad issues; assess for adjustment or replacement needs.
• Measure maximum radius against the rated capacity chart to verify allowable deflection.
• Replacing inner wear pads often requires boom removal, which may be seen as inconvenient by owners and mechanics.

Truck Mounted Cranes

• Truck mounted cranes may not have full 360° operational capability or may exhibit reduced ability in the front quadrant.
• Installation of a 5th jack at the front can enable 360° operation.

All-Terrain Cranes

• Designed for diverse ground conditions, these cranes often feature upper cab steering and travel functions.
• Jacks and outriggers can be stowed from the upper cab; they are equipped for site mobility.
• Both steering and braking systems must be examined thoroughly for safety.

City Cranes

• City cranes possess a shorter boom with multiple sections, enhancing maneuverability in urban settings.
• All-wheel steering and a low boom help in avoiding overhead obstructions.
• The crane's chassis and tyres are vital for safe operation and require thorough inspection.

Examination Components

• Conduct visual inspections of components including:
  • Manufacturer's information and duty charts, tyres and wheels, axle locking systems.
  • Crane chassis, outriggers, chassis braking systems, and visual checks of bolts, pins, and fasteners.
  • Slew section structure, slew mechanism, hydraulic fittings, and oil fluids.
  • Superstructure, jib, pivoting joints, telescoping extensions, and wire ropes.
  • Pulleys, sheaves, hook blocks, counterweights, and hoist systems.
  • Control elements including cabinets, wiring, and safety indicators.
  • Marking labels and load charts for compliance and safety verification.
• Limiting and indicating devices must be checked, including rated capacity systems and various limit indicators.