HEO Crawler Crane NC III key terms

The maximum load a crane configuration may lift under stated conditions, already reduced for boom length, radius, counterweight, and other factors shown in the manufacturer's load chart.

The total weight the crane actually supports: the load, plus rigging, slings, shackles, spreader beams, and any attached lifting accessories. It must never exceed rated capacity.

The horizontal distance from the crane's rotation center to the vertical line through the center of gravity of the suspended load, measured with the boom at the working position.

The manufacturer's table or graph giving allowable capacities at each combination of boom length, radius, and boom angle, including notes on outriggers, counterweight, and permissible configurations.

A load chart table listing the weights to subtract from the charted capacity for lifting accessories such as hook blocks, slings, and auxiliary boom heads in the current configuration.

The angle between the boom centerline and the horizontal, usually read from an indicator in the cab; capacity falls as the boom is lowered toward a longer radius.

The total effective length of the main boom or boom-and-jib combination currently pinned or telescoped, which determines the capacity curve used from the load chart.

Heavy plates or blocks mounted at the rear of the upper structure to balance the load moment; its specified amount and configuration must match the load chart being used.

The crane's resistance to tipping about a track edge or outrigger, determined by the balance of load moment, counterweight moment, and the machine's own weight on its supporting surface.

The turning effect produced by the load times its horizontal radius from the tipping line; the crane's rated capacity is limited by the maximum allowable load moment.

The total ground contact area of the crawler tracks, used with machine and load weight to estimate ground bearing pressure and whether the soil can support the crane.

The pressure the crane exerts on the soil through its tracks or mats, calculated from total weight divided by contact area and compared with the site's verified soil capacity.

A timber or steel pad placed under the tracks to spread load over a larger area, reducing ground bearing pressure and bridging soft or uneven spots on the travel path or setup position.

Placing the crane on a surface flat enough that the manufacturer's level indicator shows within tolerance, so that charted capacities and stability assumptions remain valid.

The process of pinning boom sections, inserting the boom foot pin, and connecting pendants or boom hoist ropes to build the required boom length and configuration.

A mechanical limit that prevents the boom from being raised past its maximum angle or from falling backward over the machine when the load is released.

A fixed-length wire rope or bar linking the boom tip to the upper structure to support the boom; pendants must be matched to the boom length and correctly pinned.

An auxiliary boom section attached to the main boom tip to extend reach or height, which reduces capacity and requires the corresponding jib load chart and rigging.

The systematic check of the crane and accessories before each shift, covering structure, wire ropes, hooks, brakes, limits, fluids, and safety devices, with results recorded and defects reported.

Examination of hoist, boom, and pendant ropes for broken wires, kinks, corrosion, bird-caging, and diameter reduction, comparing findings with the manufacturer's removal criteria.

A spring-loaded device on the hook opening that keeps slings and fittings from slipping off; a missing or damaged latch makes the hook unfit for lifting service.

The inside width of the hook at its narrowest point; it is measured during inspection and the hook is removed from service if the opening has stretched beyond the allowed limit.

An instrument that senses boom angle, length, and load to display radius and capacity, warning the operator with alarms and eventually cutting out unsafe movements.

A sensing and cutout system that stops hoisting or lowering when the hook block approaches the boom tip too closely, preventing rope and sheave damage.

The condition where the hook block contacts the boom tip or another sheave, which can snap the hoist rope and drop the load if the anti-two-block device fails.

The angle a sling leg makes with the horizontal; as it decreases, leg tension increases sharply, so capacity must be derated according to the sling's rated angle.

The force carried by each sling leg, which grows as the sling angle becomes shallower and must be checked against the sling's working load limit.

The maximum load a sling, shackle, or other rigging component is rated to carry in a specified configuration, marked on the item or shown on its tag.

A U-shaped connector with a pin or bolt used to join slings to hooks, eyes, or lifting lugs; its rated capacity and correct pin seating must be verified before use.

The combined weight of slings, shackles, spreader beams, and other below-the-hook gear, which is added to the load to obtain the gross load for capacity checks.

The point at which the load's weight is considered concentrated; its position relative to the hook determines load radius and whether the load will hang level.

A rope attached to the load and handled by a ground worker to control swinging and rotation, keeping personnel clear of the suspended load and the crane's pinch points.

The marked area beneath and around the load path and rotating superstructure where only essential personnel may enter, kept clear during lifting and travel.

The agreed set of arm and hand movements used by a signalperson to direct crane motions such as hoist, lower, boom up, swing, and stop when voice or radio contact is impractical.

A designated, competent worker who directs the operator using standard signals or radio, positioned where the operator and load path are clearly visible.

A lift that is unusually hazardous because of load weight, configuration, personnel nearby, or limited clearance, requiring a written plan, engineered review, and hold points before execution.

A document that sets out the load, rigging, crane configuration, radii, capacity checks, ground conditions, personnel roles, and contingency steps for a specific lift.

An inspection of the route a crawler crane will travel, checking slope, soft ground, overhead lines, obstructions, and bearing capacity before moving the machine.

The sequence at the end of operation: land and secure the load, lower the boom or hook to the specified position, apply brakes and locks, idle the engine, and secure the machine.

A form listing the inspection and operational items to be verified each shift, signed by the operator to provide a record of checks and reported defects.

A written record of any fault found during inspection or operation, describing the item, the condition, and the action taken, and forwarded to maintenance and supervision.

Controlled movement of a suspended load, including take-off, hoisting, swinging, travel, and landing, with speed and swing kept low to limit load swing.