NCCCO Mobile Crane flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Daily pre-shift inspection

Before each shift, check wire rope, hooks, rigging, brakes, clutches, limit switches, LMI/RCL, outriggers, tires, leaks, and alarms; correct defects before lifting.

Wire rope removal criteria

Remove running rope with six randomly distributed broken wires in one lay, three broken wires in one strand in one lay, wear over one-third wire diameter, or kinking and crushing.

Hook throat opening limit

Remove a hook from service when throat opening has increased more than 15 percent or when wear exceeds 10 percent of the original dimension, unless manufacturer specifies otherwise.

LMI and anti-two-block check

Confirm the load moment indicator/rated capacity limiter and anti-two-block device are powered, calibrated, and working; never bypass or disable these safety devices.

Outrigger pad purpose

Outrigger pads spread crane force over a larger soil area, reducing bearing pressure and settlement; size them for the actual crane, load, and soil capacity.

Crane leveling requirement

Set the crane level within the manufacturer's tolerance before lifting; many mobile crane load charts require level within 1 percent of grade.

Fully extended outriggers

Use the outrigger spread shown on the load chart; partial extension or on-rubber operation is permitted only if a specific chart covers that configuration.

Ground bearing pressure formula

Ground bearing pressure equals total weight carried by one outrigger divided by the effective pad area; include crane, counterweight, load, and rigging.

Counterweight and boom configuration

Capacity depends on actual counterweight, boom length, jib, and reeving; a chart for one configuration is not valid for another.

Swing radius barricade

Barricade the area within the rotating superstructure and counterweight swing radius, and keep personnel out during operation.

Setup near excavations

Keep outriggers and crawlers back from excavations, trenches, and buried utilities; soil near an edge may not support the crane's bearing pressure.

Shock loading

Shock loading is a sudden force from jerking, snatching, or rapidly stopping a load; it can exceed rated capacity and damage boom or wire rope.

Suspended load rule

Never leave the operator station with a load suspended; if the operator must leave, lower the load and secure the crane first.

Side loading

Side loading pulls the boom sideways or drags a load, creating forces the boom is not designed for; lift vertically unless the manufacturer approves otherwise.

Pick-and-carry travel

Travel with a load only when the manufacturer's pick-and-carry chart permits it, with boom low, load near ground, slow speed, and correct tire pressure.

Anti-two-block device

The anti-two-block device prevents the hook block from contacting the boom tip, which can part wire rope and drop the load; test it before lifting.

Load radius measurement

Radius is the horizontal distance from the crane's center of rotation to the center of the load or hook, not to the boom tip.

Gross capacity deductions

Subtract hook block, slings, spreader beams, jib, auxiliary boom head, and all rigging below the boom tip from the chart's gross capacity.

Between chart radii

If the actual radius falls between two chart radii, use the capacity for the next longer radius; never interpolate upward.

Area of operation

Load charts may give different capacities over the front, side, and rear; use the chart for the actual boom position and outrigger spread.

Boom deflection effect

Under load, boom deflection increases the actual load radius and can reduce capacity; recheck radius after the load is applied.

Emergency stop signal

Any person may give the emergency stop signal; the operator must stop immediately, set brakes, and not resume until the signalperson or supervisor clears it.

Designated signalperson

Only one designated, qualified signalperson should direct the operator at a time; the operator must obey that person except for an emergency stop from anyone.

Radio communication test

Before the lift, test radios, agree on channel and voice signals, and identify a backup signalperson in case communication fails.

Unclear signal response

If a hand signal or radio instruction is unclear, the operator must stop and wait until clear communication is restored.

Hoist hand signal

Hoist: forearm vertical, forefinger pointing up, and hand moving in a small horizontal circle.

Dog everything signal

Dog everything: clasp hands in front of the body; it tells the operator to stop and hold all crane functions.

Power line approach distance

OSHA minimum approach: 10 ft for 50 kV or less, 15 ft for 50–200 kV, 20 ft for 200–350 kV, and greater distances for higher voltages.

Operator refusal authority

The operator has the authority and duty to stop and refuse any lift that is unsafe, exceeds capacity, or violates standards or the manufacturer's instructions.

Governing standards

Mobile crane operations follow OSHA 29 CFR 1926 Subpart CC, ASME B30.5, and the manufacturer's manual; the most restrictive applicable requirement governs.

Inspection types

Mobile cranes require shift, monthly, and annual/comprehensive inspections; deficiencies must be corrected and recorded before the crane is returned to service.

Qualified rigger and signalperson

Only qualified riggers and signalpersons may perform rigging and signaling duties; the operator must verify qualifications before starting the lift.