Mobile Cranes and Boom Maintenance

Questions and Answers

What feature can enable a truck mounted crane to operate at 360°?

Increasing the boom length

Fitting a 5th jack at the front end (correct)

Adding a counterweight

Reducing the number of jacks

What is a key characteristic of all-terrain cranes?

They have a fixed upper cab for controls.

They can only operate in urban environments.

They are designed for varied ground conditions. (correct)

They are only used on flat surfaces.

Which function is essential to examine when inspecting all-terrain cranes?

Lifting speed of the crane

Steering and braking systems (correct)

The adjustable boom mechanism

Weight capacity limit

What design feature distinguishes city cranes from typical mobile cranes?

Shorter boom with more sections Signup and view all the answers

Why is the boom of city cranes kept low?

To avoid overhead obstructions in urban areas Signup and view all the answers

What is a unique feature of all-terrain cranes regarding their operational functions?

They can stow jacks and outriggers from the upper cab. Signup and view all the answers

How do all-terrain cranes facilitate travel around a site?

By integrating steering and braking in the upper cab Signup and view all the answers

What is the primary advantage of the all-wheel steering system in city cranes?

Enhanced maneuverability in tight urban spaces Signup and view all the answers

What is the function of the boom pins in a mobile telescoping crane?

To attach the telescopic boom to the swivel structure Signup and view all the answers

What can result from failing to ensure that locking pins are in place?

Boom collapse due to the pin working loose Signup and view all the answers

What should be observed about derrick pistons while lifting the boom?

Any visible oil indicates a potential seal leak Signup and view all the answers

What does a downward bend in the boom indicate when not under load?

Possible wear pad adjustment or replacement is needed Signup and view all the answers

How can one verify the allowable deflection of a telescoping boom?

By comparing the maximum radius against the rated capacity chart Signup and view all the answers

What is a commonly reported action regarding boom maintenance?

Adjusting or replacing wear pads Signup and view all the answers

What should be checked in hydraulic connections to ensure safe operation?

Tightness and absence of leaks in fittings Signup and view all the answers

What does flexing of modern booms under load signify?

Normal and allowable behavior of the boom Signup and view all the answers

What component is crucial to the crane's stability and safety during operation?

Tyres and wheels Signup and view all the answers

Which part requires visual inspection along with its fittings to ensure safe crane operation?

Fly jib mounting attachment Signup and view all the answers

What does the rated capacity system measure in a mobile crane?

Load, movement, and radius Signup and view all the answers

Which of the following components is specifically examined throughout its full range of movement?

Slewing mechanism Signup and view all the answers

What should be inspected visually alongside the wire running and static ropes?

Hook blocks and sheaves Signup and view all the answers

What components are part of the crane's limiting and indicating devices?

Rated capacity system and anemometer Signup and view all the answers

During inspection, which of the following items requires visual checks for performance?

Outrigger jacks and beams Signup and view all the answers

Which aspect of the crane's structure is assessed for both operation and visual integrity?

Telescoping extensions Signup and view all the answers

Study Notes

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.

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Description

This quiz covers essential aspects of mobile telescoping cranes, focusing on boom maintenance and safety inspections. Participants will learn about boom flexing, pin checks, hydraulic connections, and their implications on crane performance. Understanding these factors is crucial for safe crane operation.