Crane and Rigging Glossary

The indoor half of a split air conditioning system, containing the blower and the evaporator coil that moves cooled air through the ducts. It sits in an attic, a closet or a mechanical room rather than outside. Air handlers are usually the lighter of the two pieces but the more awkward to get into position. On a split system the crane work is normally about the outdoor condenser, not this.

See alsoCondenserPackage unitRoof curb

A crane mounted on a truck chassis, so the machine that lifts the load is also the machine that drove there. The boom is the arm that telescopes out and up. Boom trucks fit in places a larger crawler crane could never reach, like a residential street or a storage yard drive aisle. This is the workhorse for HVAC sets, spa placements and truss work around Lake Havasu City.

See alsoMobile crane serviceReachTight access lift

A way of rigging a sling where it wraps around the load and passes back through its own eye, so it tightens as the load goes up. It is useful on poles, pipe, posts and bundles that have no lifting points. A choker grips well but it carries less than the same sling in a straight or basket hitch, so the operator allows for that. On a finished pole or a painted sign post, the sling gets padded where it bites.

See alsoSlingRiggingTag line

The outdoor half of a split system, the unit with the fan on top that sheds heat to the air. On a residential job it usually sits on a pad beside the house, and on a commercial job it may live on the roof. When there is no gate wide enough or the pad is behind a block wall, the condenser goes over the wall by crane. Newer high-efficiency models tend to be bigger and heavier than the unit they replace, which catches people out.

See alsoAir handlerPackage unitOver-structure placement

The heavy steel fitting at each of the eight corners of a shipping container, with oval holes built for lifting and for locking containers together. A container is lifted from its four top castings, or from the bottom ones with a spreader bar, and never by the doors or the side walls. The castings carry the load straight into the frame of the box. Before a pick, the operator checks them for rust, cracks or damage from earlier handling.

See alsoLifting eyeShackleSpreader barDunnage

An operator comes with every crane, every time. Bare rental, where you take the machine and run it yourself, is not offered here. The reason is simple: reading the load chart, judging the ground and calling the rigging is the actual job, and it is not something you hand to a customer with the keys. What you are hiring is the judgment as much as the steel.

See alsoOwner-operatedLoad chartRigging

Timber blocks, steel plate or heavy plastic pads placed under the outriggers to spread the load over a wider area. They keep the legs from sinking into soft ground or punching a mark into asphalt, pavers or a new concrete driveway. More cribbing means lower pressure at any one point. On a decorative driveway or a soft shoulder, this is the difference between a clean job and a repair bill.

See alsoGround bearing pressureOutriggers

Timber blocks or bearers laid under a load before it is set down, so there is a gap to pull the slings out afterwards. Without it, a machine or a stack of material lands flat on the slings and they are trapped underneath. Dunnage also spreads the weight on a finished surface and keeps a load off wet or uneven ground. On a container, a roofing pallet or a machine skid, it is placed and checked before the load comes down, not shoved under once it is hanging.

See alsoCribbing and matsSlingSoft setCorner casting

The area around and under the load, and around the swinging body of the crane, that stays clear of people for the whole lift. It includes the tail swing, the circle the back of the crane sweeps as it rotates, which surprises people standing what they thought was a safe distance behind it. Kids, pets and parked cars come out of this zone before the lift starts. It is marked or called out during the briefing so nobody has to guess where the line is.

See alsoSignal personPre-lift briefingTag line

How much weight each outrigger pushes into the ground per square foot. A crane concentrates most of its weight through four small pads, so the ground under those pads matters more than the ground anywhere else. Around here you often have a few inches of desert soil over caliche, which is usually solid, but a backfilled utility trench or fresh landscaping right beside it is not. This is why the operator walks the setup area before anything comes out.

See alsoOutriggersCribbing and matsTight access lift

A fixed set of arm and hand motions used to tell the operator to hoist, lower, swing, extend or stop. They are standardized so an operator and a signal person read them the same way on any site, even on a windy day with a diesel engine running. The stop signal can be given by anyone on site, at any time, and it is always obeyed. Radios get used too, but hands keep working when a battery dies.

See alsoSignal personExclusion zonePre-lift briefing

A ring or looped fitting built into or bolted onto an item by its manufacturer, meant to be the attachment point for a hook or shackle. Rooftop units, generators, transformers and machinery often ship with four of them, and some items have threaded points that take a rated eye bolt or swivel hoist ring. A lifting eye is rigging hardware with a known rating, which is why the operator looks for them first. The thing to watch is a rusted or bent eye on an older unit, because age and weather can quietly take that rating away.

See alsoPad eyeRiggingShacklePackage unit

The manufacturer's table that tells the operator exactly what the crane can lift at a given boom length, radius and outrigger setup. It is the governing document for the whole job, and the operator reads it for the configuration actually being used that day, not for a general idea. No honest answer about capacity exists without it. If someone gives you a firm yes without asking how far the load has to travel horizontally, they have not looked at one.

See alsoRated capacityLoad radiusOutriggersPre-lift briefing

The horizontal distance from the crane's center of rotation to the load hanging on the hook. This is the single most important number a customer does not know they need. Capacity drops sharply as radius grows, so where the truck can park matters as much as what the item weighs. When you call, pacing off the distance from the likely setup spot to where the load has to land is the most useful two minutes you can spend.

See alsoRated capacityLoad chartReach

A crane that drives to your site on its own wheels, sets up, does the work and leaves the same day. There is no assembly crew and no separate trailer of counterweight arriving first. People often picture the tall tower cranes bolted to a construction site for months, which is a completely different machine. A mobile crane is built to show up, lift, and be gone before dinner.

See alsoBoom truckCrane with operatorOutriggers

The legs that swing or slide out from the truck and lift the wheels off the ground, giving the crane a wide, stable footprint. They need firm ground and more width than most people expect, which is why a lift sometimes needs more of your driveway than you assumed. If they cannot be fully extended, capacity is reduced and the load chart is read differently. Everything the crane can do traces back to how well those four pads are set.

See alsoGround bearing pressureCribbing and matsLoad chart

Lifting an item up, over a house, wall or other structure, and down into a space with no ground-level route in. Nearly every yard in this town is ringed by a block wall with no gate wide enough for a spa or a shed, which is a large part of why the crane exists here. The load never travels over occupied space, and the path is planned before anything leaves the ground. Height of the obstacle plus distance to the landing spot is what decides whether it works.

See alsoReachLoad radiusSoft setTight access lift

The person who quoted your job is the person running the crane on the day. You get one point of contact from the first phone call through to the load landing. Nothing gets lost between a sales desk, a dispatcher and a driver who has never seen your site. If you sent photos of your driveway, the operator standing in it has already looked at them.

See alsoCrane with operatorMobile crane servicePre-lift briefing

A rooftop air conditioning system with the compressor, coil and blower all built into one cabinet, so the whole thing lands as a single piece. Most commercial buildings and many local homes use these, which is why you see boxy units sitting on flat roofs all over town. They are lifted as one heavy, wide load rather than in parts. The replacement rarely matches the old unit's footprint exactly, so the curb underneath often needs adapting.

See alsoRoof curbAir handlerCondenserSoft set

A flat steel plate with a hole in it, built into a skid, a tank or a structural frame as a designed lifting point. Where a lifting eye is a ring or loop, a pad eye is a plate that a shackle pins through. Both are only as good as what they are attached to, so the operator checks the plate, the hole and the frame around it before picking. An item with no designed lifting points gets rigged from its frame with slings instead, never from a bracket that was not built to lift.

See alsoLifting eyeShackleRiggingSpreader bar

A short talk with everyone on site before the crane picks anything up, covering the load, the path it will travel, who signals, where people stand and what stops the job. It takes a few minutes and it is where problems get found while they are still cheap to solve. Anyone present can raise a concern or call a stop, including the homeowner. If the plan changes during the day, the briefing happens again before work restarts.

See alsoSignal personExclusion zoneHand signalsLoad chart

A concrete wall or structural section poured off site and delivered finished, ready to be lifted into place. Panels are heavy, tall and want to hang flat, so they are rigged to stand up and land square onto their bearing points. Each one is braced as it is set, before the crane releases it. Cast-in lifting inserts on the panel are the attachment points, and the operator checks their condition before picking.

See alsoLifting eyeRiggingRoof trussSoft set

The maximum a crane can lift at its shortest working radius, in ideal conditions, with everything set up perfectly. It is a headline number, not a promise about your job. A 40-ton crane does not lift 40 tons out at the end of the boom, and most people assume it does. What it can lift over your back wall depends on how far away that wall is.

See alsoLoad radiusLoad chartReach

How far the boom extends, measured to the tip. Maximum reach is not maximum reach with a load on the hook, and that is the misunderstanding worth clearing up early. A boom stretched to its full length is working at its weakest, so the heavier the item, the shorter the reach available for it. Reach tells you whether the boom can get there at all, and the load chart tells you what it can carry once it does.

See alsoLoad radiusLoad chartOver-structure placement

Everything that connects the load to the hook: slings, shackles, spreader bars, chains and hardware. Choosing it correctly is most of the skill in a lift, because the crane only lifts what the rigging is holding, and it holds it in a particular way. Rigging decides whether a load hangs level, whether it can be turned in the air, and whether the item gets marked up in the process. The operator brings and inspects the rigging for the job.

See alsoSlingShackleSpreader barLifting eye

The raised frame on the roof that a package unit sits down onto, sealing the opening where the ductwork passes through. The curb has to line up with both the roof opening and the new unit's base. Replacement units almost never share the old footprint, so a curb adapter often has to bridge the gap. The adapter goes up on the same crane setup as the unit, so the new unit lands on it instead of waiting for a second visit.

See alsoPackage unitSpreader barSoft set

A factory-built triangular frame of wood or steel that forms the roof structure, delivered to site in a stack and set one at a time. Trusses are long, light for their size and floppy on their side, so they need careful rigging and a tag line to stay controlled in the air. Wind is the deciding factor on truss day more than weight ever is. Setting them by crane is faster and far safer than trying to walk them up by hand.

See alsoSpreader barTag linePrecast panelSoft set

A U-shaped steel connector closed by a removable pin, used to join a sling to a lifting point or to another piece of rigging. It is the small part people ignore and it carries the whole load. Shackles are rated, and the rating only applies when the pin is the right one and it is fully seated. A shackle with a bolt through it instead of its proper pin is not a shackle, it is a hazard.

See alsoRiggingSlingLifting eye

The one person responsible for directing the operator when the load goes somewhere the operator cannot see, such as behind a house or down onto a roof. Only one person signals at a time, and everyone else stays quiet, because two people waving at once is how loads get put in the wrong place. The signal person watches the load, not the crane. On smaller residential jobs this role is filled by the crew, not by the homeowner.

See alsoHand signalsExclusion zonePre-lift briefing

The strap or chain that goes around or through the load to connect it to the hook. Nylon and polyester web slings are gentle on finished surfaces like a spa shell or a painted machine, while chain and wire rope handle heat, sharp steel edges and rough loads. Every sling has a working limit that changes with the angle it hangs at, so the same strap is not equally strong in every arrangement. Slings get inspected before use and pulled from service when they show damage.

See alsoRiggingShackleSpreader bar

Landing a load slowly and under control onto a finished surface so it touches down without impact. The last few inches are done at a crawl, with the crew guiding it into position by hand. This is what protects a tile roof, a new deck, a pool coping or a fresh concrete pad from the moment of contact. Getting a load to the right spot is the easy part, and setting it down gently is the part that takes patience.

See alsoTag lineOver-structure placementRoof curb

A rigid beam hung under the hook that holds the sling legs apart so they pull straight up instead of squeezing inward. Without one, a wide load like a hot tub shell or a long truss gets crushed or bowed by the very straps holding it. It also keeps the sling angles shallow, which preserves sling capacity. On wide or fragile items it is not an accessory, it is the reason the item arrives undamaged.

See alsoSlingRiggingRoof truss

A rope attached to the load and held by a crew member on the ground to keep it from spinning or drifting as it travels. A suspended load wants to rotate, and a long item like a truss or a beam will do it on its own if nothing controls it. The tag line lets a person steer the load without ever being underneath it. On a breezy Havasu afternoon it is the difference between a controlled placement and a wrestling match.

See alsoExclusion zoneSoft setRoof truss

A lift where setup room, not weight, is the limiting factor. Think of a narrow drive aisle in a boat and RV storage yard, a side yard between two houses, or a cul-de-sac with cars on both sides. The crane may have to set up farther away than anyone would like, which increases the radius and reduces what it can lift. Solving these usually starts with a photo of the approach and a measurement of the narrowest point.

See alsoLoad radiusOutriggersOver-structure placement