GB/T 6974.2-2010 is Part 2 of the crane terminology standard series, specifically governing the definitions of terms used for mobile cranes. Given the wide variety of mobile crane types, a unified terminology system is essential for effective industry communication and the development of technical specifications. The following sections provide a systematic interpretation of the core terms defined in this standard.

Standard Scope and Terminology Framework

GB/T 6974.2-2010 is the second part of the GB/T 6974 "Cranes — Vocabulary" series. Building on the general terminology defined in GB/T 6974.1, this part focuses specifically on standardizing the terminology for mobile cranes. The standard contains over 200 specialized terms, organized in a logical sequence covering machine types, components, mechanisms, parameters, safety devices, and operations. Standardized terminology is critical for design communication, manufacturing acceptance, operator training, and safe use of mobile cranes — enabling technicians across different regions and manufacturers to communicate using consistent terms, thereby avoiding misunderstandings and safety risks caused by inconsistent wording.

Machine Type Terminology

The standard defines terms for various mobile crane configurations: Truck Crane — a crane mounted on a truck chassis, using the truck engine for travel and an upper engine (or hydraulic system) to power lifting operations. All-Terrain Crane — a crane built on a specially designed all-terrain chassis (with multiple driven and steering axles and hydro-pneumatic suspension), combining the on-road travel capability of a truck crane with the off-road performance of a rough-terrain crane. Crawler Crane — a crane that uses crawler tracks instead of wheels, characterized by low ground bearing pressure, the ability to travel with a suspended load, and operation without outriggers. Rough-Terrain Crane — a crane with a specially designed tire chassis capable of traveling and operating on demanding job sites. Loader Crane — a crane mounted on a cargo truck in front of the loading bed, used for loading and unloading the truck's own cargo.

Structure and Mechanism Terminology

The standard provides detailed definitions for the structures and mechanisms of mobile cranes: Telescopic Boom — a boom system consisting of multiple nested box-section sections that extend and retract via hydraulic cylinders or wire rope mechanisms. Basic Boom — the largest section of the telescopic boom, fixed to the slewing platform, into which all other sections retract. Boom Extension/Retraction Mechanism — the device that extends or retracts the boom sections, using hydraulic cylinders (synchronized or sequential) or wire rope mechanisms. Slewing Platform — the rotating structural component that carries the boom, counterweight, and upper engine, connected to the chassis frame via the slewing bearing. Outrigger — a hydraulic or manual support device that extends outward from the chassis or crawler frame and rests on the ground, including H-type, X-type, and folding (frog-type) outriggers.

Performance Parameter Terminology

The standard precisely defines the performance parameters for mobile cranes: Rated Lifting Capacity — the maximum load a crane is permitted to lift under specific boom length, working radius, and outrigger conditions (including the weight of the hook and lifting spreader). Working Radius — the horizontal distance from the crane's slewing centerline to the hook's vertical line. Boom Length — the length from the boom's root hinge point (or root pin) to the centerline of the boom tip sheave. Load Moment — the product of the rated lifting capacity and the corresponding working radius; the most important parameter for assessing a mobile crane's lifting capability. Lifting Height — the vertical distance from the ground (or the bottom of the outriggers) to the highest position of the hook. Ground Bearing Pressure — the average pressure exerted by the crawler tracks on the ground under maximum lifting capacity conditions. Maximum Outrigger Pressure — the maximum pressure exerted on the ground by a single outrigger under the most unfavorable positioning (used for ground reinforcement design).

Safety Device Terminology

The standard unifies the terminology for mobile crane safety devices: Load Moment Limiter (LML) — a safety device that monitors the lifting load, working radius, and boom angle in real time, providing an early warning when approaching the rated load and automatically cutting off power to dangerous movements in the event of an overload. Height Limit Switch — a device that automatically cuts off power to the hoisting-up direction when the hook reaches its maximum allowable height. Radius Limit Switch — a device that triggers an alarm and cuts off power to dangerous movements when the boom luffs to its maximum or minimum allowable working radius. Anti-Tipping Device — a mechanical or hydraulic device that prevents the boom from tipping backward beyond its design limit under no-load or light-load conditions. Hydraulic Lock Valve — a single-direction check valve installed on outrigger and luffing cylinders that prevents cylinder retraction in the event of an unexpected hydraulic pipeline failure. Kelude technical staff use the standard terminology defined in GB/T 6974.2 for all technical documentation and customer communications, ensuring clear and consistent communication.

Mobile Crane Terminology Classification Reference

The following reference table outlines the core parameter configurations for mobile crane terminology categories, intended for use by selection and operating personnel.

Kelude Heavy Industry: Overhead & Gantry Crane Solutions

Kelude Heavy Industry specializes in the design and manufacture of industrial overhead cranes and gantry cranes. Our product range covers a wide spectrum of applications, from single-girder and double-girder bridge cranes to versatile gantry systems and specialized explosion-proof or low-headroom configurations. We provide complete lifting solutions tailored to your operational needs.

Diverse Crane Types for Every Application

Our portfolio includes a comprehensive selection of crane types, each engineered for specific performance and durability standards. Whether you require a compact single-girder crane for light assembly work or a heavy-duty double-girder system for intensive production, we offer a model to match your exact requirements. Options include top-running and under-running configurations, wall-mounted jib cranes, and explosion-proof designs for hazardous environments.

Key Features Enhancing Productivity and Safety

Our cranes are equipped with advanced features designed to boost operational efficiency and ensure maximum safety. The anti-sway system minimizes load swing for precise positioning, while variable-frequency drives (VFD) provide smooth acceleration and deceleration, reducing mechanical stress. For enhanced safety, we integrate overload protection, emergency stops, and audible/visual alarms as standard. Optional features include remote control operation, magnet systems, and specialized grabs.

Customized Solutions & Engineering Support

We understand that every facility is unique. Our engineering team works closely with you to design a crane system that integrates seamlessly into your existing workflow. From calculating the optimal span and lifting height to integrating with automated production lines, we provide comprehensive support. We also offer installation, commissioning, and after-sales maintenance services to ensure long-term, reliable operation.

Frequently Asked Questions (FAQ)

Q: What is the typical lead time for a standard overhead crane?
A: Lead times vary depending on the crane's specifications and complexity. For standard single-girder cranes, it is typically 4-6 weeks from order confirmation. Double-girder or customized systems may require 8-12 weeks.

Q: Do you provide installation services?
A: Yes, we offer full installation and commissioning services by our trained technicians. Alternatively, we can provide detailed installation drawings and supervise your own installation team if preferred.

Q: What safety certifications do your cranes comply with?
A: Our cranes are designed and manufactured in accordance with international standards, including ISO 4301 for crane classification and IEC 60204-32 for electrical equipment. Specific certifications can be provided upon request based on your region and application.

Q: Can you supply spare parts for existing cranes?
A: Absolutely. We maintain a stock of common spare parts and can manufacture specific components to order. Our parts department can assist with identifying the correct parts for your crane model.

Q: What is the maximum span or lifting capacity available?
A: Our standard range covers spans up to 40 meters and capacities up to 100 metric tons. For specialized projects, we can engineer solutions beyond these figures. Please contact us with your specific requirements.

Q: Do you offer cranes for explosive atmospheres?
A: Yes, we provide explosion-proof crane configurations designed for hazardous areas, classified according to ATEX or NEC standards. These cranes feature specially protected electrical components and mechanical parts to prevent ignition risks.

Q: How do I determine the right crane capacity for my application?
A: You need to consider the heaviest load you will lift, the frequency of use, and the duty cycle. Our engineering team can assist you in calculating the appropriate crane class and capacity based on your operational profile.

Q: What is the difference between a bridge crane and a gantry crane?
A: A bridge crane runs on overhead runways installed on the building structure, while a gantry crane is supported by legs that travel on ground rails or wheels. Gantry cranes are ideal for outdoor applications or where a building runway is not feasible.

Q: Can the cranes be operated remotely?
A: Yes, most of our cranes can be equipped with wireless remote controls, allowing operation from a safe distance. This enhances operator safety and improves load positioning accuracy.

Q: What maintenance is required for these cranes?
A: Regular maintenance is crucial for safe and efficient operation. We provide a recommended maintenance schedule, including daily inspections, periodic lubrication, and annual comprehensive checks by qualified personnel. We also offer service contracts for ongoing support.

Q: Do you provide cranes that meet specific international standards for export?
A: Yes, we design and build cranes to comply with various international standards, including ISO, FEM, and CMAA specifications, ensuring they meet the regulatory requirements of your destination country.

Q: Can you integrate the crane with our existing automation system?
A: Certainly. Our cranes can be equipped with various communication interfaces (e.g., Profibus, Ethernet/IP) and sensors to integrate seamlessly with your PLC or warehouse management system for automated lifting and material handling.

Q: What is the warranty period on your cranes?
A: We offer a standard warranty of 12 months from the date of commissioning, covering defects in materials and workmanship. Extended warranty options are available upon request.

Q: How do you ensure the quality of your cranes?
A: Our manufacturing process adheres to strict quality control procedures, from incoming material inspection to final load testing. Each crane undergoes a thorough inspection and functional test before dispatch to ensure it meets our high standards.

Q: Can you provide references or case studies?
A: Yes, we can share relevant case studies and references from our global customer base upon request. This can help you understand how our solutions have been applied in similar industries.

Q: What information do you need for a quotation?
A: To provide an accurate quote, we typically need the following: lifting capacity, span, lifting height, duty class/working group, power supply, and any specific environmental conditions (e.g., indoor/outdoor, temperature, hazardous area). Our sales team will guide you through the specification process.

Q: Are your cranes suitable for outdoor use?
A: Yes, we offer weatherproof and corrosion-resistant options for outdoor applications. These include sealed electrical enclosures, galvanized or painted surfaces, and components rated for the expected temperature range.

Q: Can you help with the foundation design for a gantry crane?
A: We provide detailed foundation load data and rail alignment specifications. For complex installations, we can also offer engineering consultation to ensure the foundation is designed correctly for the crane's operational loads.

Q: Do you offer training for crane operators?
A: Yes, we can provide on-site or remote training programs for your operators and maintenance personnel, covering safe operating procedures, daily checks, and basic troubleshooting.

Q: How can I contact your sales team for more information?
A: You can reach our sales team via the contact form on our website, by email, or by phone. Our representatives are available to discuss your requirements and provide expert advice.

Q: What payment terms do you accept?
A: We typically accept T/T (wire transfer) or L/C (letter of credit) for international orders. Specific terms can be negotiated based on the project value and your company's credit standing.

Q: Do you have a minimum order quantity?
A: No, we do not have a strict minimum order quantity. We can supply a single crane or multiple units, depending on your project needs.

Q: Can you customize the crane's color or branding?
A: Yes, we can paint the crane in your corporate colors and apply your logo or branding as required. This is a common request for companies looking to maintain a consistent brand image.

Q: What is the lifespan of your cranes?
A: With proper maintenance and operation, our cranes are designed for a long service life, typically exceeding 20 years. The actual lifespan depends on the duty cycle and adherence to the maintenance schedule.

Q: Do you provide after-sales technical support?
A: Yes, our after-sales support team is available to assist with any technical issues, troubleshooting, and spare parts inquiries. We are committed to supporting our customers throughout the crane's entire lifecycle.

Q: Can your cranes be used in conjunction with other material handling equipment?
A: Absolutely. Our cranes can be integrated with other equipment such as vacuum lifters, clamps, or rotating devices to handle specific loads. We can design the end effector to suit your exact material handling process.

Q: How do you handle shipping and logistics for international orders?
A: We have experience exporting cranes worldwide. We arrange secure packing, often in containers or on flat racks, and coordinate shipping with reliable freight forwarders. We handle all export documentation to ensure a smooth delivery process.

Q: Is it possible to upgrade an existing crane with your technology?
A: Yes, we offer modernization and retrofit services for existing cranes, including upgrading control systems, installing anti-sway technology, or increasing safety features. This can be a cost-effective alternative to purchasing a new crane.

Q: What are the power supply options for your cranes?
A: Our cranes can be designed for various power supplies, including standard three-phase AC voltages (e.g., 220V, 380V, 415V, 480V) at different frequencies (50Hz or 60Hz). We ensure the electrical components are compatible with your local grid.

Q: Do you offer cranes with a low-headroom design?
A: Yes, we offer low-headroom cranes specifically designed for facilities with limited vertical space. These cranes maximize the hook height by optimizing the distance between the runway beam and the top of the crane.

Q: Can you provide a crane with a special lifting height?
A: Yes, we can engineer cranes with custom lifting heights to suit your building dimensions and operational requirements. This may involve special hoist configurations or additional mast sections.

Q: What is the maximum ambient temperature your cranes can operate in?
A: Our standard cranes are designed for ambient temperatures up to 40°C (104°F). For higher temperature environments, we can provide special components and cooling systems to ensure reliable operation.

Q: Do you offer cranes for cleanroom environments?
A: Yes, we can provide cranes with special features for cleanroom applications, such as sealed motors, stainless steel components, and specialized lubrication to minimize particle generation.

Q: Can you supply a crane with a double hoist or auxiliary hoist?
A: Yes, we can equip cranes with a main hoist and an auxiliary hoist of lower capacity for handling lighter loads at higher speeds, improving operational flexibility.

Q: How do you ensure the stability of a gantry crane?
A: Gantry crane stability is ensured through proper design calculations, including wind load considerations for outdoor units, and the use of counterweights or outriggers where necessary. We also provide rail clamps and travel limit switches for safety.

Q: What type of motors do you use?
A: We use high-quality electric motors, typically squirrel-cage induction motors, which are reliable and require low maintenance. For precise positioning, we can integrate variable-speed drives.

Q: Can you provide a crane with a remote monitoring system?
A: Yes, we offer optional remote monitoring systems that track crane usage, performance, and potential maintenance needs via IoT technology, allowing for predictive maintenance and reduced downtime.

Q: What is the noise level of your cranes?
A: We design our cranes to operate with low-noise levels, typically below 80 dB(A) at the operator's position, depending on the configuration and speed. We can implement additional noise reduction measures if required.

Q: Do you provide cranes for container handling?
A: Yes, we offer specialized gantry cranes, such as RTGs (Rubber-Tired Gantry) and RMGs (Rail-Mounted Gantry), designed for efficient container handling in ports and intermodal yards.

Q: Can your cranes be used in a corrosive environment?
A: Yes, we can provide cranes with enhanced corrosion protection, including hot-dip galvanized structures, stainless steel fasteners, and specially coated electrical panels for use in marine or chemical environments.

Q: What is the process for obtaining a spare part?
A: You can contact our spare parts department with your crane's serial number and the part description. We will identify the correct part and provide a quotation. Most standard parts are shipped within 24 hours.

Q: Do you offer a service contract for regular maintenance?
A: Yes, we offer flexible service contracts that include scheduled inspections, preventive maintenance, and priority response for repairs. This helps maximize your crane's uptime and extends its lifespan.

Q: Can you provide a crane with a special paint finish?
A: Yes, we offer various paint systems, including epoxy and polyurethane finishes, with different thicknesses and colors to meet specific environmental or aesthetic requirements.

Q: How do you test the cranes before delivery?
A: Each crane undergoes a rigorous testing procedure, including a load test to 125% of the rated capacity, functional tests of all movements, and safety device checks. We provide test certificates upon request.

Q: What is the difference between a top-running and under-running crane?
A: A top-running crane operates on rails mounted on the top of the runway beams, offering higher capacity and hook height. An under-running crane runs on the lower flange of the runway beam, which can be more cost-effective for lighter capacities and lower headroom.

Q: Can you help us with the installation of the crane runway?
A: While we typically supply the crane itself, we can provide detailed runway beam specifications and alignment tolerances. We can also recommend qualified installation partners in your region.

Q: Do you offer financing options for crane purchases?
A: We can sometimes facilitate financing through third-party partners, depending on the project size and your company's financial standing. Please discuss your needs with our sales team.

Q: What is the maximum wind speed your outdoor cranes can withstand?
A: Our outdoor cranes are designed to operate safely up to a certain wind speed (typically 20 m/s for operation) and can withstand higher wind speeds when parked and secured with rail clamps. Specific wind load calculations are provided for each project.

Q: Can you provide a crane with a special control voltage?
A: Yes, we can design the control circuits to operate on various voltages, such as 24V AC/DC or 110V AC, to meet your safety requirements or existing control system standards.

Q: Do you offer cranes with a galvanized structure?
A: Yes, for enhanced corrosion resistance, we can offer hot-dip galvanized main structural components, which is particularly beneficial for outdoor or high-humidity environments.

Q: What is the expected energy consumption of your cranes?
A: Energy consumption varies based on the crane's capacity, duty cycle, and speed. We use energy-efficient motors and drives, and regenerative braking systems can be implemented to reduce energy usage in certain applications.

Q: Can you provide a crane with a special hook path or trolley configuration?
A: Yes, we can design custom trolleys with features such as rotating hooks, telescopic masts, or double hooks to suit specific lifting requirements.

Q: Do you have distributors or agents in my country?
A: We have a network of distributors and agents in many countries. Please contact us to check for representation in your region, or we can work with you directly.

Q: What is the lead time for spare parts?
A: Standard spare parts are typically shipped within 24-48 hours. Custom-made parts may take longer, depending on the complexity and our production schedule.

Q: Can you provide a crane with a higher duty cycle for heavy applications?
A: Yes, we can design cranes for heavy-duty classifications (e.g., FEM 4m or ISO M7/M8) with reinforced structures, higher-rated motors, and more frequent maintenance intervals to handle intensive operations.

Q: Do you offer a crane with a synchronized lifting system?
A: Yes, for handling long or bulky loads, we can provide cranes with synchronized hoists that operate in tandem, ensuring even load distribution and precise positioning.

Q: Can you provide a crane with a special power supply, such as battery or diesel?
A: Yes, for applications where mains power is unavailable, we can design gantry cranes with diesel generators or battery packs for propulsion and lifting operations.

Q: How do you ensure the safety of the operator during maintenance?
A: We incorporate safety features such as lockable main disconnects, emergency stop buttons, and platforms with guardrails for safe access to maintenance points. We also provide clear lockout/tagout procedures in the manual.

Q: Can you provide a crane with a load cell or weighing system?
A: Yes, we can integrate load cells into the hook or hoist to provide accurate weight readings, which can be displayed locally or transmitted to your control system for process monitoring.

Q: What is the minimum span available for your bridge cranes?
A: The minimum span is typically around 3 meters, but this can be customized based on the specific application and the runway beam configuration.

Q: Do you offer cranes with a special coating for food processing environments?
A: Yes, we can provide cranes with food-grade lubricants, stainless steel components, and smooth surfaces that are easy to clean, suitable for hygienic environments.

Q: Can you provide a crane with a dual-speed or variable-speed hoist?
A: Yes, we offer hoists with dual-speed motors or variable-frequency drives for precise speed control, allowing for both fast positioning and delicate load handling.

Q: How do you handle the disposal of old cranes?
A: We can provide guidance on the safe decommissioning and recycling of old cranes. In some cases, we can offer a trade-in program when purchasing a new crane.

Q: What is the maximum capacity for your single-girder cranes?
A: Our standard single-girder cranes typically go up to 20 metric tons. For higher capacities, a double-girder configuration is usually more efficient and cost-effective.

Q: Can you provide a crane with a special paint color for safety zones?
A: Yes, we can paint specific parts of the crane, such as the hook or bumpers, in safety colors (e.g., yellow or red) to improve visibility and safety in the workplace.

Q: Do you offer a crane with a remote diagnostic feature?
A: Yes, our advanced control systems can include remote diagnostics, allowing our engineers to access the PLC and troubleshoot issues over the internet, reducing downtime.

Q: What is the standard warranty period for electrical components?
A: The standard warranty for electrical components is typically 12 months, covering defects in materials and workmanship. Some components, like motors, may have a longer warranty from the manufacturer.

Q: Can you provide a crane with a special hook height?
A: Yes, the hook height can be customized by adjusting the height of the end carriages, trolley, or using a longer hoist cable. We can design to achieve the maximum possible hook height for your building.

Q: Do you offer cranes for use in underground mines?
A: Yes, we can provide specialized cranes for underground mining applications, with features such as flameproof motors, low-profile designs, and enhanced dust protection.

Q: How can I track the status of my order?
A: Once your order is confirmed, you will be assigned a dedicated project manager who will provide regular updates on the manufacturing progress and shipping schedule.

Q: Can you provide a crane with a special control interface, such as a touchscreen?
A: Yes, we can equip cranes with modern control interfaces, including touchscreen pendants or wireless tablets, providing intuitive operation and real-time data display.

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