GB/T 26474-2011 Mobile Crane Terminology Standard
GB/T 26474-2011 "Mobile Cranes – Terminology" is the dedicated terminology standard for mobile cranes. It defines the specific terms and definitions for truck cranes, all-terrain cranes, rough-terrain cranes, crawler cranes, and other mobile crane types, aligning with ISO 4306-2:2012 (MOD). The standard provides a unified terminology foundation for the design, manufacturing, and operation of mobile cranes.
Scope of Application and Standard Positioning
GB/T 26474-2011 applies to five major categories of mobile cranes: truck cranes (mounted on standard commercial truck chassis, road speed ≥70 km/h), all-terrain cranes (purpose-built all-terrain chassis combining high-speed road travel with off-road capability), rough-terrain cranes (purpose-built tire chassis designed for operation on unimproved surfaces), crawler cranes (crawler travel mechanism, capable of pick-and-carry loads with low ground bearing pressure), and telescopic handler cranes (telescopic boom fitted with fork attachments). The standard establishes a unified technical language for terminology across all these crane types. Kelude Heavy Industry organizes its production strictly in accordance with this standard.
Boom and Lifting Attachment Terminology
Boom terminology defined in the standard covers: the basic boom (fully retracted, shortest configuration with maximum strength), the fully extended boom (fully extended, providing maximum lifting height but minimum lifting capacity), the main boom (primary load-bearing boom mounted on the slewing platform), the fly jib (auxiliary boom attached to the main boom tip), the telescopic boom (multi-section box-section segments nested, driven by hydraulic cylinders or rope systems), and the lattice boom (welded structural steel or tube lattice sections, assembled in segments). Lifting attachment terminology covers hooks (forged single hooks or laminated hooks fitted with hook latches), lifting eyes, lifting electromagnets, grabs (grab buckets), and container spreaders.
Safety Devices and Performance Parameter Terminology
Safety device terminology covers the load moment limiter (LML), which continuously calculates the actual load moment based on the current lifting capacity and real-time working radius — issuing a yellow early warning at 90% of the rated limit, a red alarm at 105%, and automatically cutting off dangerous-direction movements while preserving safe-direction functions such as lowering and radius reduction; the load indicator, which displays the current actual load as a percentage of the rated lifting capacity; the radius indicator, which shows the horizontal distance from the hook center to the slewing center in real time; the spirit level, which indicates the chassis level status — after outrigger deployment, the chassis inclination angle must not exceed 3°; and anti-over-hoisting and anti-over-lowering devices, which prevent wire rope over-hoisting fracture or complete payout.
The slewing lock secures the slewing platform in the transport position — the platform must be locked during travel. The outrigger lock prevents accidental outrigger extension while the crane is in transit. Outrigger pressure indicators, installed in each outrigger hydraulic circuit, display the actual ground bearing pressure of each outrigger, enabling operators to identify any risk of an outrigger lifting off the ground.
Performance parameter terminology covers the maximum rated lifting capacity (the maximum load in tons permitted at minimum radius with outriggers fully extended), the maximum load moment of the basic boom (the product of lifting capacity and working radius in kN·m in the basic boom configuration), the maximum lifting height with the boom fully extended (the highest hook position in meters at minimum radius with the boom fully extended), working speeds (hoisting, luffing, telescoping, and slewing speeds), and outrigger span (longitudinal and transverse spans, which determine the stabilizing moment in the forward/rearward and lateral directions, respectively). The standard also defines mobility parameters — approach angle, departure angle, minimum ground clearance, and minimum turning radius — which determine the crane's travel capability across varying terrain conditions.
| Term Category | coverage Content | Number of Terms | Corresponding ISO |
|---|---|---|---|
| Classification Term | 5Mobile Crane Types | 5Items | ISO 4306 Cranes - Vocabulary-2 |
| Boom Lifting spreader | Telescopic boom/lattice boom/Hook | 6Items | §4 |
| safety device | torque limiting/limit switch/Locking | 7Items | §5 |
| performance parameters | Lifting Capacity/Torque/speed | 6Items | §6 |
| Mobility/Terrainability | Approach Angle/Departure Angle | 5Items | §7 |
| Boom Type | structural features | Telescoping Method | Applicable Models | Application |
|---|---|---|---|---|
| Base Boom | Fully Retracted | Shortest Configuration | All Models | Strength Maximum |
| fully extended boom | Fully Extended | Longest Configuration | All Models | Lifting Height Maximum |
| Telescopic boom | box section Telescoping/Nesting | Hydraulic/Rope Reeving | Truck-Mounted/All-Terrain | Most Common |
| lattice boom | Structural Steel Section/Steel Tube Welding | Sectional Disassembly | Crawler/large tonnage | Dead Weight Light |
Standard Comparison and Application Guidance
GB/T 26474-2011 is closely related to GB/T 6974.2 (Crane Terminology — Part 2: Mobile Cranes). While the latter focuses on standardized definitions of general terminology, the former emphasizes a terminology system and operating specifications tailored to engineering application scenarios. Used together, the two standards provide comprehensive terminology support for the design & manufacturing, operator training, and safety management of mobile cranes.
In practice, it is recommended that mobile crane users combine this standard with GB/T 6067.3 (Safety Regulations for Mobile Cranes) and GB/T 23723.3 (Safe Use of Mobile Cranes) to build a complete knowledge framework — from terminology understanding to safe operation. Operators should prioritize mastering key terms used in daily lifting operations, including the lifting capability table, load moment limiter (LML) alarm thresholds, and outrigger operating procedures.
Related Standards: GB/T 6974.6-2008 — Crane Terminology — Part 6: Railway Cranes · GB/T 6974.7-2008 — Crane Terminology — Part 7: Floating Cranes
Related Standard
• ISO 12480-2:2008 — Cranes — Safe Use — Part 2: Mobile Cranes
FAQ
Q: What is the core difference between a truck crane and an all-terrain crane?
A: A truck crane is built on a standard commercial truck chassis with leaf-spring suspension and rear-axle drive, offering excellent on-road performance but limited off-road capability. An all-terrain crane uses a dedicated all-terrain chassis with independent suspension, multi-axle drive, and hydro-pneumatic vibration damping, allowing both high-speed highway travel and operation on rough terrain. All-terrain cranes typically cost 2 to 3 times more than truck cranes of equivalent lifting capacity.
Q: What is a lifting capability table, and why must operators follow it strictly?
A: The lifting capability table specifies the maximum permitted lifting capacity for every combination of jib length and working radius, with separate values for fully extended and partially extended outriggers. Operators must refer to the table to determine the rated lifting capacity for their current jib length and working radius, and the suspended load must never exceed that value. Lifting capability tables vary by manufacturer and model — they are not interchangeable.
Q: Why is the lifting capacity of a crawler crane reduced when traveling under load?
A: During lifting operations, a crawler crane relies on its track width to provide stabilizing moment. When traveling under load over uneven ground, the additional overturning moment generated reduces the effective stabilizing moment. As a result, the permissible lifting capacity while traveling under load is generally limited to 70%–80% of the rated lifting capacity.
Q: What does outrigger pressure indicate?
A: Outrigger pressure reflects the actual load carried by each outrigger. Under normal conditions, pressures should be reasonably balanced across all outriggers. If one outrigger's pressure approaches zero, it means that outrigger is about to lift off the ground — a sign that the crane is nearing overturning. Conversely, excessive pressure on a single outrigger may cause ground settlement beneath it. Operators can monitor the outrigger pressure gauges at any time to assess the crane's stability status.
