MT Crane/Hoisting Operator flashcards

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

Boom length definition

The straight-line distance from the boom foot pin to the boom tip sheave center, measured along the boom; used with radius and angle to determine capacity from the load chart.

Load moment definition

The product of the load weight and the operating radius; load moment indicators use this value to warn of overload conditions and prevent tipping or structural failure.

Counterweight purpose

A mass mounted at the rear of the upperworks that increases lifting capacity by counterbalancing the load; it also increases tail swing and ground bearing pressure.

Jib effect on capacity

A jib extends beyond the boom tip, increasing radius and reducing capacity; the load chart for the jib configuration must be used, not the main boom chart.

Rated capacity determination

The lowest of structural, stability, or line pull limits for the specific crane configuration, boom length, and radius; always deduct the weight of rigging below the boom tip.

Net capacity calculation

Gross capacity from the load chart minus the weight of all below-the-hook devices (hook block, slings, spreader beams) equals the net capacity available for the load.

Pick-and-carry chart use

When traveling with a load, use the manufacturer's pick-and-carry chart, which accounts for travel speed, ground conditions, tire pressure, and steering mode; never use the static chart.

Radius measurement point

Radius is the horizontal distance from the center of rotation to the center of the load, measured with the load suspended; it is not the distance to the boom tip.

Sling tension formula

For a two-leg sling, tension per leg = load / (2 × sin(angle from horizontal)). As the angle decreases, tension increases; at 30° each leg carries the full load.

Shackle side loading

Side loading of a shackle reduces its rated capacity and is prohibited unless the shackle is specifically rated for side loading; always pull in line with the pin.

Synthetic sling inspection

Inspect synthetic slings for cuts, abrasion, UV degradation, and chemical damage; remove from service if red warning yarn is visible or if the tag is missing.

Spreader beam function

A spreader beam distributes load between lifting points and must be rated for the load and configuration; verify proof load test date and inspect for damage before use.

Daily crane inspection

Check engine oil, coolant, hydraulic fluid, tires, outrigger pads, and safety devices such as LMI, anti-two-block, and horn; document any deficiencies before operating.

Hook throat opening limit

Replace a hook when the throat opening increases by more than 15% of the original dimension or when wear exceeds 10%; also check for cracks and deformation.

Anti-two-block test

Test the anti-two-block device daily by slowly hoisting until the device stops the hoist; never bypass or disable it, as it prevents rope damage and load loss.

Wire rope inspection criteria

Remove wire rope from service when there are 6 randomly distributed broken wires in one lay or 3 broken wires in one strand in one lay, or when diameter reduction exceeds limits.

Ground bearing pressure

Outrigger load divided by pad area must be less than the soil's allowable bearing capacity; use mats or cribbing to increase area and reduce pressure.

Outrigger setup rules

Fully extend and pin outriggers, set on stable level ground, and use pads; never block on cribbing that can shift or crush, and re-check level after setup.

Crane level tolerance

Keep the crane level within the manufacturer's tolerance, often 1% or 3 degrees; use a level indicator and adjust outriggers to achieve level before lifting.

Tail swing hazard

The rear of the upperworks can swing beyond the outriggers; barricade the swing radius and keep personnel clear to prevent crushing injuries.

Signal person responsibility

Only one designated signal person directs the lift; all signals must be understood by the operator before the lift begins, and emergency stop is any signal.

Shock loading avoidance

Start and stop smoothly; sudden load changes can exceed capacity and cause structural failure or tipping. Never drag loads sideways or jerk the load.

Personnel lifting restrictions

Never lift personnel unless using a man basket designed for that purpose and following the manufacturer's instructions and applicable regulations; otherwise prohibit.

Tag line use

Use tag lines to control the load from a safe distance; personnel must not touch the load or rigging while suspended, and must stay clear of the swing radius.

Power line approach distance

Maintain minimum approach distance: for voltages up to 50 kV, 10 ft (3 m); for higher voltages, add 0.4 in (1 cm) per kV above 50 kV, per OSHA 1926.1408.

Power line contact response

If contact occurs, stay in the cab, warn others away, and have the utility de-energize the line; if you must exit, jump clear and shuffle away to avoid step potential.

Wind speed limits

Cease operations when wind speed exceeds the manufacturer's limits or when the load's sail area makes control difficult; wind can reduce capacity and cause loss of control.

Environmental hazard assessment

Evaluate lightning, high winds, ice, poor visibility, heat, and cold; stop operations and secure the crane when conditions exceed manufacturer's limits or safe operating parameters.

Wire rope removal criteria

Remove wire rope when there are 6 randomly distributed broken wires in one lay, 3 broken wires in one strand in one lay, or when diameter reduction exceeds allowable limits.

Sheave groove wear

Worn sheave grooves can damage wire rope and reduce capacity; replace sheaves when groove wear exceeds manufacturer's limits or when flanges are broken.

Brake test procedure

Test service, parking, and hoist brakes before lifting; ensure they hold the load without drift. Maintain brake linings and adjust per manufacturer's specifications.

OSHA crane standard

OSHA 29 CFR 1926 Subpart CC governs cranes and derricks in construction; 1910.180 covers crawler, locomotive, and truck cranes in general industry.

Operator certification requirement

OSHA requires crane operators on construction sites to be certified by an accredited organization and to carry proof of certification; training alone is not sufficient.

Critical lift definition

A lift that exceeds 75% of capacity, involves personnel, or has special hazards; it requires a documented lift plan, pre-lift meeting, and additional supervision.

ASME B30.5 scope

ASME B30.5 covers mobile and locomotive cranes, including inspection, testing, maintenance, and operation requirements; it is a key reference for crane safety.