ISO 4306-2:2012 Cranes Vocabulary Explained: Mobile Crane Terms
ISO 4306-2:2012 "Cranes — Vocabulary — Part 2: Mobile Cranes" is the international standard governing mobile crane terminology. It standardizes terms and definitions across mobile crane types (truck cranes, crawler cranes, tire cranes, loader cranes, etc.), covering four categories: type classification, main structure, mechanism system, and parameter indicators.
Mobile Crane Type Classification Terms
The standard classifies mobile cranes by chassis configuration into truck cranes (mounted on a general-purpose or purpose-built truck chassis), crawler cranes (equipped with crawler traveling gear), tire cranes (mounted on a purpose-built tire chassis or all-terrain chassis), and loader cranes (mounted on a cargo vehicle for loading and unloading operations).
By structural type, cranes are grouped into telescopic boom cranes (boom consisting of multiple telescoping sections), lattice boom cranes (boom of lattice construction), and knuckle boom cranes (boom made up of multiple hinged segments that fold). The standard also unifies operational terms such as boom angle (the included angle between the boom axis and the horizontal plane) and extension rate (the ratio of the current telescopic boom length to its fully retracted length).
Main Structure Terminology
The standard standardizes terms for the main structural components of mobile cranes, including the chassis frame (the base frame carrying all crane mechanisms), the outrigger system (support devices that increase the support area and enhance stability, including H-type, X-type, and swing-out outriggers), the slewing ring (the slewing device connecting the upper structure to the undercarriage), and the counterweight (balancing weight positioned at the rear of the slewing platform to improve lifting capacity).
Boom system terms include: base boom (the first section of the main boom), telescopic section, boom tip sheave (head sheave), and jib (an extension boom added to the main boom). Outrigger system terms include vertical jack and horizontal outrigger beam. The standard also specifies precise usage of counterweight terminology — counterweights are divided into fixed and variable types, with the superlift counterweight being an additional configuration for ultra-large tonnage cranes.
| Term Category | Number of Terms | Main Content | International Code |
|---|---|---|---|
| type classification | 12Clause | Truck/Crawler/Tire/Truck-mounted, etc. | §2.1 |
| main structure | 20Clause | Chassis/Outrigger/Slewing/Counterweight Truck-mounted, etc. | §2.2 |
| mechanism system | 15Clause | Hoisting / Lifting/Luffing/Slewing/traveling Truck-mounted, etc. | §2.3 |
| parameter indicators | 10Clause | Lifting Capacity/Working radius/Height/speed | §2.4 |
| safety device | 8Clause | Load moment limiter (LML)/Height Limit Switch Truck-mounted, etc. | §2.5 |
Mechanism System Terminology
The standard standardizes the terminology for each working mechanism of mobile cranes—the hoisting mechanism (which controls hook lifting and lowering, comprising the hydraulic motor, reducer, drum, and wire rope system); the luffing mechanism (which changes the boom angle, available in two configurations: hydraulic cylinder luffing and wire rope luffing); the slewing mechanism (which enables the upper structure to rotate, incorporating the swing motor, reducer, and slewing bearing); and the travel mechanism (which provides self-propelled movement, including drive axles, tires or tracks, and the steering system).
Hydraulic system terminology covers: the hydraulic pump (which converts mechanical energy into hydraulic energy), the hydraulic motor (an actuator that converts hydraulic energy back into mechanical energy), the directional control valve (the core component that distributes hydraulic oil flow and controls actuation direction), and the counterbalance valve (a safety component that prevents uncontrolled load lowering). For overall machine stability, the standard defines the key terms tipping line and stability factor.
Key Parameter Terminology
The standard provides standardized definitions for the primary parameter indicators of mobile cranes—rated lifting capacity (the maximum load a crane is permitted to lift under specified operating conditions), maximum load moment (the product of rated lifting capacity and the corresponding working radius), maximum lifting capacity at minimum boom length, lifting capacity with outriggers fully extended, and boom length. By unifying the expression of these parameters, the standard ensures that product specifications from different manufacturers are directly comparable.
Kelude Heavy Industry strictly applies the terms and definitions set forth in ISO 4306-2:2012 across its technical files and manuals, ensuring unambiguous technical exchange both domestically and internationally. For export-model mobile cranes, all nameplate markings and technical documentation follow the standard's terminology without exception.
| Parameter Name | Unit | Definition | standard number |
|---|---|---|---|
| Rated Lifting Capacity | t | Specifiedoperating conditions Maximum under Lifting Mass | §4.1 |
| maximum load moment | t·m | Rated Lifting Capacity×Corresponding Working radius | §4.2 |
| Basicjib length Height | m | Telescopic boom Length with all sections retracted | §4.3 |
| Maximum lifting height | m | Ground to Hook Highest position | §4.4 |
| Outrigger Span | m | Fully extended Outrigger Lateral distance | §4.5 |
FAQ
Q: Which crane types does ISO 4306-2:2012 cover?
A: It applies to truck cranes, crawler cranes, tire cranes, loader cranes, and all-terrain cranes. It does not cover tower cranes or bridge cranes, which are governed by ISO 4306-3 and ISO 4306-1, respectively. The standard's terminology covers all technical documentation and operating instructions for the listed crane types.
Q: How do telescopic boom and lattice boom mobile cranes differ?
A: A telescopic boom consists of multiple rectangular or elliptical cross-section sections that extend and retract via hydraulic cylinders, offering a compact transport profile. A lattice boom is a welded truss structure built from angle steel and steel tubes, requiring sectional transport and on-site assembly. The former delivers speed and flexibility, while the latter holds the advantage at ultra-large tonnages.
Q: In which languages is the standard available?
A: The standard's body text is published in English, French, and Russian, with a Chinese equivalent version (GB/T 6974.2). Kelude Heavy Industry prepares its mobile crane technical files bilingually in Chinese and English, with terminology fully aligned to the international standard.
Q: What are the common outrigger system terms?
A: H-type outrigger — horizontal beams extend and retract laterally; X-type outrigger — legs deploy in an X configuration; swing-out outrigger — legs pivot outward from the chassis. Precise terminology is essential for effective technical exchange and safe operating guidance.
