Loader Cranes

A loader crane is a hydraulic crane mounted on a truck chassis, usually behind the cab or at the rear of the load bed. Most loader cranes have an articulated boom that folds like a knuckle when not in use, which is why they are often called knuckle boom cranes. In the United Kingdom and Ireland the machine is widely known as a “Hiab”, after the Swedish company that pioneered it, while in North America the terms knuckle boom crane and articulating crane are common.

The idea is simple: the truck carries its own lifting equipment, so it can load and unload building materials, machinery, containers and other goods without waiting for a separate crane or forklift. Over the decades, loader cranes have grown from small units that lifted a few hundred kilograms to heavy machines that compete with small mobile cranes on many construction jobs.

Brief History of Loader Cranes

The modern loader crane was born in Sweden. HIAB (Hydrauliska Industri AB) was founded in Hudiksvall in 1944 by Eric Sundin, who saw that the truck’s engine could power a hydraulic crane. In 1947 the company introduced what is generally considered the first hydraulic truck-mounted loader crane. The concept spread quickly across Scandinavia and the rest of Europe, where short delivery distances and dense towns favoured self-loading trucks.

In the following decades other European manufacturers entered the market, especially in Italy, Austria, Germany and Denmark. The folding knuckle boom, telescopic extensions, a second jib (the fly jib), radio remote control and electronic overload protection gradually became standard. Today loader cranes are a large industry in their own right, with a wide range of sizes and a strong presence on construction sites, in builders’ merchants’ fleets and in utility, forestry and recycling work.

How a Loader Crane Works

A loader crane is a compact hydraulic system built around a column and an articulated boom.

Base and subframe. The crane is bolted to a subframe that transfers loads to the truck chassis. The subframe design is essential for stability and for the truck’s structural integrity.
Column and slewing. The crane column rotates on a rack-and-pinion slewing system or, on larger models, a slewing ring, often with continuous rotation.
Inner boom and outer boom. The main boom is lifted by a large cylinder. The outer boom is connected by a knuckle joint and moved by a second cylinder, which allows the crane to fold compactly and reach over obstacles.
Telescopic extensions. Hydraulic extensions inside the outer boom increase reach.
Fly jib. Many medium and large cranes can carry an additional articulated jib at the boom tip for more reach and height.
Stabilisers. Hydraulic legs, which extend sideways and down, lift weight off the truck’s suspension and give the crane a stable base.
Power and control. A power take-off on the truck drives the hydraulic pump. The operator controls the crane from the ground, from a seat on top of the crane or, most often today, by radio remote control.

Types of Loader Cranes

Light Loader Cranes

Small cranes mounted on light trucks and vans, used by builders’ merchants, landscapers and service fleets. They lift pallets, bags and small machines close to the vehicle.

Medium Loader Cranes

The core of the market, usually mounted on two- and three-axle trucks. They are used for building material deliveries, roof trusses, precast elements and general construction.

Heavy Loader Cranes

Large cranes on multi-axle chassis with long telescopic booms and fly jibs. They can reach heights and radii comparable to small mobile cranes and are used for steel erection, precast installation, HVAC units and machinery handling.

Rear-Mounted and Demountable Cranes

Cranes mounted at the rear of the truck leave the load bed free and can reach behind the vehicle. Some smaller cranes can be removed and moved between vehicles.

Special Versions

The same concept is used for timber and forestry cranes with a grapple, recycling cranes, and marine and offshore loader cranes on vessels and quays. Straight telescopic boom truck cranes, common in North America, are a related but different design.

Size Classes

Loader cranes are usually classified by lifting moment, expressed in tonne-metres ™ or kilonewton-metres (kNm): the load multiplied by its distance from the crane column.

Class	Typical lifting moment	Typical use
Light	up to about 10 tm	Merchants’ deliveries, landscaping, service work
Medium	about 10 to 40 tm	Building materials, trusses, small precast
Heavy	about 40 to 100 tm	Steel, precast, machinery, rooftop units
Very heavy	about 100 tm and more	Large construction lifts, crane hire work

Figures are indicative and vary by manufacturer.

Attachments

The crane can carry a hook, pallet forks, a clamshell or rotating bucket, block and brick grabs, timber and scrap grapples, vacuum lifters for glass and panels, and man baskets where local rules allow them. A hydraulic rotator between boom tip and tool lets the operator turn the load. Winches can be added for lifts below ground level or for greater height.

Main Manufacturers

Hiab, the Swedish pioneer of the hydraulic loader crane.
Palfinger, an Austrian manufacturer with a large range of loader cranes.
Fassi, an Italian specialist in loader cranes.
Effer, an Italian brand known for heavy cranes, part of Hiab.
Cormach and PM Group in Italy.
HMF in Denmark.

Main Uses of Loader Cranes

Delivery of building materials, blocks, bricks and timber directly to site.
Installation of trusses, precast elements, steel beams and modular units.
Placement of rooftop plant, generators and HVAC equipment.
Transport and placement of containers, site cabins and toilets.
Utility work, including poles, transformers and pipes.
Forestry, recycling and waste collection with grapples and buckets.

Choosing a Loader Crane

Lifting moment and reach. Match the crane to the heaviest loads and the longest radius needed, including over walls and scaffolding.
Truck chassis. The crane’s weight reduces the truck’s payload. Axle loads, subframe design and road weight limits must be checked together with the bodybuilder.
Stabilisers. Wider stabiliser spreads give more capacity, but site space is often limited. Systems that adapt capacity to the actual stabiliser position help on narrow sites.
Fly jib or not. A fly jib gives reach and height but adds weight and cost. It is useful for hire and construction work, less so for simple deliveries.
Controls. Radio remote control lets the operator stand where the load is visible. Operator training and ergonomics count as much as crane size.
Service and support. Loader cranes work hard and need regular inspection of hoses, cylinders, slewing systems and safety devices. A local dealer and service network matter as much as the specification sheet.

Safety

The main risks with loader cranes are overturning, overloading, contact with overhead power lines, dropped loads and crushing between the load and the vehicle or a structure. Stabilisers must be fully deployed as required and placed on firm ground, with pads where needed. Operators should follow the load chart, use the overload protection system, keep people out of the working area and check lifting accessories. Many incidents happen close to power lines on delivery sites, so a site check before setting up is essential. The crane must be correctly folded and secured before the truck moves.

Trends and Technology

Loader cranes are becoming larger, lighter and smarter. High-strength steels and new boom profiles increase capacity without adding weight to the truck. Electronic stability systems calculate capacity from the actual stabiliser positions and the truck’s load. Remote controls with displays, camera support and automated functions such as automatic folding and unfolding are spreading. Electric power take-offs and battery packs allow crane operation with the truck engine switched off, useful in cities and at night deliveries. Telematics help fleets monitor use, maintenance and overloads.

Key Terms

Knuckle boom: an articulated boom that folds at a joint between inner and outer boom.
Lifting moment: load multiplied by radius, the main measure of a loader crane’s size.
Fly jib: an extra articulated jib mounted on the tip of the main boom.
Stabilisers: hydraulic legs that support the truck during lifting.
Subframe: the structure connecting the crane to the truck chassis.
Hiab: the brand name commonly used as a generic word for a loader crane in the UK.

Frequently Asked Questions

What is the difference between a loader crane and a mobile crane? A loader crane is mounted on a truck that also carries loads, while a mobile crane is a dedicated lifting machine. Large loader cranes overlap with small mobile cranes on many jobs.

Why is a loader crane called a Hiab? HIAB introduced the first hydraulic truck-mounted crane in the 1940s, and in the UK its name became a generic term for this kind of crane.

How is a loader crane rated? Mainly by lifting moment, in tonne-metres or kilonewton-metres, together with maximum reach and capacity at different radii.

Can a loader crane lift people? Some cranes can be fitted with approved work baskets, but rules vary by country and many require specific equipment and certification.

How much does a loader crane reduce truck payload? It depends on the crane size and the chassis. A heavy crane with a fly jib can weigh several tonnes, so crane, subframe, stabilisers and payload must be planned together.