JB/T 7020 Crane End Carriage Standard Guide
JB/T 7020 – End Carriage Standard for Cranes is a key technical specification in the crane industry. Developed as a machinery-sector standard, it specifically governs end carriage design and manufacturing for cranes.
The standard provides a unified technical basis for design engineers, inspection bodies, and end users. Kelude strictly follows its technical requirements throughout product development and manufacturing to ensure compliance and reliability.
Application Scope and Positioning of the Standard
JB/T 7020 defines the technical requirements and safety indicators for crane end carriages, covering all types of lifting appliances with a Rated Lifting Capacity above 0.5 t. The standard applies not only to the design and manufacturing of new equipment but also provides clear technical guidance for the inspection, maintenance, and modification of existing cranes. As a key component of the crane standard system, it aligns with the EN 13001 Crane Safety Standard series and ISO 4309 Wire Rope Inspection Standard, forming a complete technical specification framework. The clearly defined technical parameters and Safety factor requirements give designers a solid design basis, while also providing quantifiable acceptance criteria for Type Test and Factory Acceptance Test conducted by third-party inspection bodies.
Core Technical Parameters and Design Requirements
Under JB/T 7020, the design and manufacturing of crane end carriages must meet a comprehensive set of technical parameters. These values are established through extensive test data and safety engineering principles, covering everything from material selection to structural design. The Safety factor ranges specified in the standard account for fatigue life and limit load conditions under demanding operating conditions.
Key Technical Parameters – Comparative Analysis
| Item | technical requirements | Description |
|---|---|---|
| End Carriage Stiffness | Full-load deflection≤L/1000 | Mid-span Concentrated Loadoperating conditions |
| Connection bolt | 10.9Grade Friction Type High-Strength Bolt | Final Tightening Torque Method+Angle Method |
| Wheel Base Tolerance | Diagonal Difference≤2mm/Wheelbase Difference≤3mm | Four-Wheel Rail Contactwasher / shimadjustment |
| Horizontal Guide Roller | Clearance2~5mm | and Crane Rail Side Contact/Fit |
| Material | Q355B (≈S355JR)(Standard)/Q420B(Heavy Duty) | D/EGrade Low-Temperature Impact |
| Preload | Design Pretension≥80%Limit | Overtightening Not Exceeding110% |
Inspection Requirements and Intervals
Factory Acceptance Tests are performed on every unit at the manufacturer's facility by the quality inspection department. Each unit that passes inspection is accompanied by a detailed inspection report and a Certificate of Conformity. Type Tests are conducted when a new product enters production, when manufacturing is transferred to another facility, or when significant structural changes are introduced. For equipment already in service, the periodic inspection interval is determined by the work duty classification and operating environment, with a maximum interval of 12 months.
| Item | technical requirements | Description |
|---|---|---|
| End Carriage Deflection | Level Instrument Measurement | Annual+≤L/1000 |
| Bolt Torque | Torque Wrench Spot Check10% | Annual+Under-Tightening Retightening |
| Wheel load Balanced | Four-Wheel Contact Inspection | Annual+washer / shimadjustment |
| Guide Roller Clearance | Clearance Measurement | Quarterly+2~5mm |
Safe Operation and Management Requirements
The standard places particular emphasis on operator qualification and training, requiring that all operators complete specialized training and obtain the appropriate certification before being allowed to work. User units must establish a comprehensive equipment file management system that documents the full installation, usage, maintenance, and inspection history of the equipment. Any safety hazards identified must be addressed through the rectification procedure specified in the standard, ensuring that equipment remains in a safe and controllable condition at all times.
FAQ
Q: What vertical stiffness requirement does the JB/T 7020 standard impose on the end carriage?
A: L/1000 at full load. The end carriage must have sufficient torsional stiffness to prevent torsional deformation caused by irregularities in the crane rail.
Q: What are the installation requirements for high-strength bolts connecting the end carriage to the main girder under JB/T 7020?
A: Grade 10.9 friction-type high-strength bolts. Initial tightening to 50% of final torque, followed by final tightening using the torque-plus-angle method. Friction surface coefficient ≥ 0.45. 10% of bolts subject to random inspection.
Q: What wheel base and diagonal tolerance requirements does JB/T 7020 specify for the end carriage wheel block?
A: Diagonal tolerance ≤ 2 mm, wheel base tolerance ≤ 3 mm. All four crane wheels must contact the rail simultaneously. Adjustment is made using shims at the three support points.
Q: What lateral clearance adjustment does JB/T 7020 require for the horizontal guide roller?
A: 2–5 mm clearance, with proper contact against the side of the crane rail. Replace the guide roller when wear exceeds 10%.
Kelude — Specialized in crane design and manufacturing, strictly adhering to the JB/T 7020 standard system, providing lifecycle service.
