Free NCCCO Mobile Crane Assembly and Disassembly Questions and Answers — Questions and Answers
Question 1: When assembling a mobile crane, in what position should the superstructure typically be before installing counterweights?
- Slewed 90 degrees to the side
- Slewed directly over the rear of the carrier (Correct answer)
- Slewed directly over the front of the carrier
- At any position as long as the crane is level
Correct answer: Slewed directly over the rear of the carrier
For most mobile cranes, the superstructure must be slewed over the rear of the carrier for counterweight installation. This position provides maximum stability and correctly aligns the counterweight tray or hydraulic pinning system with the counterweights on the ground or transport vehicle.
Question 2: When assembling a lattice boom, what is the most critical step after connecting two sections with pins?
- Painting the connection point to prevent rust
- Ensuring all connection pins are fully inserted and secured with keepers (Correct answer)
- Checking the boom angle indicator for accuracy
- Attaching the wire rope to the boom tip
Correct answer: Ensuring all connection pins are fully inserted and secured with keepers
The structural integrity of a lattice boom depends on the secure connection of its sections. After inserting the main connection pins, it is absolutely critical to ensure they are fully seated and that all retaining clips, cotter pins, or other keepers are properly installed to prevent the pins from backing out during operation.
Question 3: Before beginning any assembly or disassembly procedures, what must be ensured regarding the crane's outriggers?
- They are extended to at least 50% of their full length
- They are fully extended as required, set on pads, and the crane is level with tires clear of the ground (Correct answer)
- The outrigger pads are at least 12 inches thick
- The outrigger beams are freshly greased
Correct answer: They are fully extended as required, set on pads, and the crane is level with tires clear of the ground
A stable foundation is the first principle of safe crane operation and assembly. Before lifting any components, the outriggers must be extended to the manufacturer's required configuration, placed on blocking or pads sufficient to support the load, and used to level the crane until the tires are clear of the ground.
Question 4: What is the only authoritative source for the correct sequence and procedures for assembling or disassembling a specific mobile crane?
- The company's general safety manual
- The senior operator's experience
- The crane manufacturer's operator/assembly manual (Correct answer)
- OSHA 1926 Subpart CC
Correct answer: The crane manufacturer's operator/assembly manual
Every crane model has unique assembly and disassembly procedures designed by the engineers who built it. The manufacturer's manual is the only authoritative source for the correct sequence, required tools, and safety precautions. Failure to follow these specific instructions can lead to component damage or catastrophic failure.
Question 5: When assembling a luffing jib on the ground, what is a primary hazard the crew must control?
- The jib is typically heavier than the main boom
- The potential for uncontrolled movement due to the jib's center of gravity (Correct answer)
- The jib requires a special type of wire rope that is hard to install
- The jib pins are a different color than the main boom pins
Correct answer: The potential for uncontrolled movement due to the jib's center of gravity
Luffing jibs and other long attachments often have a center of gravity that can cause them to become unstable and swing or 'flop' unexpectedly during assembly if not properly blocked and supported. The assembly plan must account for this and ensure the component is stable at all times before lifting.
Question 6: During disassembly, an assist crane removes the main boom. What must the lift director's calculation of the boom's weight include?
- The total weight of the boom, including all rigging, wire rope, and the hook block (Correct answer)
- The length of the boom only
- The weather forecast for the next week
- The cost of the assist crane rental
Correct answer: The total weight of the boom, including all rigging, wire rope, and the hook block
To safely lift the boom, the lift director must calculate the total weight of the 'pick'. This includes not just the boom structure, but also the weight of the main hook block, any auxiliary blocks, all the wire rope spooled on the drum, and the rigging used to connect the boom to the assist crane.
Question 7: What is a key element of a good site layout plan for mobile crane assembly/disassembly?
- Ensuring the area is close to a public road for easy access
- Having a designated, level, and firm area with sufficient space for all components and assist cranes (Correct answer)
- Placing the components in the order they were removed from the truck
- Making sure the area has good cell phone reception for communication
Correct answer: Having a designated, level, and firm area with sufficient space for all components and assist cranes
A well-planned assembly/disassembly area is critical for safety and efficiency. The area must be large enough to lay out the boom, jib, counterweights, and other components without being crowded. Most importantly, the ground must be firm and level to ensure the stability of the main crane, assist cranes, and the components themselves.
Free NCCCO Mobile Crane Assembly and Disassembly Questions and Answers
When assembling a mobile crane, in what position should the superstructure typically be before installing counterweights?