Mar. 29th, 2025
1. Regulations and Standards
1.1 International common law
According to the U.S. Occupational Safety and Health Administration (OSHA) standards, the basic inspection frequency of 20 ton gantry crane is:
Daily: Pre-operational visual inspection (wire rope, brake, track)
Monthly: Detailed inspection of critical structural components (main beams, end beam connections)
Annual: full certification by a third party organization
ISO 4309 specifically emphasizes that spreader pulley blocks must be disassembled and inspected every 250 hours of use, a clause that was ignored in a Brazilian port in 2022, resulting in a million-dollar loss due to a broken hook block.
1.2 China's National Standard
According to GB/T 14405-2011 Article 8.3:
Weekly: emergency brake function must be tested and recorded
Quarterly: measure the deflection under the main beam (allowable value ≤ L/700, L is the span)
Annual inspection: need to be issued by the special equipment inspection agency qualified report
Real case: In 2023, a shipyard in Ningbo was fined 380,000 RMB and suspended by the regulator for failing to implement quarterly deflection measurement.
1.3 Hidden clauses of insurance companies
Most equipment insurance contracts contain **“reasonable inspection obligation” clauses**:
If the accident is caused by the lack of minimum inspection frequency, the insurance company can refuse to pay the claim
A Shenzhen logistics company's $2 million claim was rejected due to lack of monthly bolt inspection records.
Countermeasure: Keep a complete inspection log for at least 3 years and use an electronic signature system (Huada iCheck intelligent log tool is recommended).
2.Daily Inspection
2.1 Pre-shift mandatory check 4 (with a quick checklist)
| Inspection items |
Qualification standards |
Tools |
Risk tips |
| Wire rope |
≤3 broken wires within 1 meter |
Magnifying glass + ruler |
Sudden breakage of broken wires over the limit |
| Track |
No debris/oil stains |
Laser track meter |
Derailment due to obstacles |
| Brake |
Empty hook sliding distance ≤5cm |
Tape measure |
Brake failure leads to collision |
| Limiter |
Stop immediately after triggering |
Manual test button |
Accident due to over travel |
2.2 Monitoring of 20-ton gantry crane in operation
Bearing damage: continuous “humming” sound, frequency changes with rotational speed.
Gear wear: intermittent “clicking” sound, aggravated when loaded.
Motor overheating: emitting a burnt odor, shell temperature > 65 ℃ (infrared temperature gun detection)
Emergency mnemonic: stop immediately for abnormal noise, cut off power for overheating, and report the odor.
2.3 Record the shift change of 20-ton gantry crane
Compliance records need to contain:
Inspection time/personnel/equipment number
Abnormal phenomena and handling measures
Electronic signatures of both parties + time stamp
Template example:
Date: 2024-06-15
Shift: Morning shift (8:00-16:00)
Record of abnormality: 2cm gravel found on the east track of 3# 20 ton gantry crane, cleaned up
Signature: Oliver (Operator) ✔️ James (Receiver) ✔️
3. Regular in-depth Inspection
3.1 Weekly inspection of 20-ton gantry crane
Key tasks:
Brake clearance adjustment: Measure the clearance between brake shoe and brake wheel with a plug ruler (standard 0.8-1.2mm)
Pulley groove wear detection: stand a $1 coin into the groove, if the exposed portion is >1/3 it needs to be replaced
Recommended toolkit: Huada weekly inspection set (including explosion-proof plug ruler, coin gauge and other 6-piece set)
3.2 Monthly Inspection of 20-ton gantry crane
Operation Procedure:
Laser measurement of deflection under the main beam (allowable value ≤ span/700)
Randomly check 10% of high strength bolts and test the preload force with torque wrench
Test emergency power switching response time (should be <2 seconds)
Data comparison: After a user strictly enforces monthly inspection, the bolt loosening rate drops by 72%.
3.3 Annual Inspection of 20-ton gantry crane
List of mandatory inspection items:
Ultrasonic flaw detection (main beam weld, hook neck)
Insulation resistance test (motor ≥1MΩ, line ≥0.5MΩ)
Rated load test (static load 1.25 times, dynamic load 1.1 times)
Money-saving tips: choose the annual inspection service in cooperation with the manufacturer (e.g.
Huada annual inspection package is 15% cheaper than the third party).
4. Inspection Strains Under Special Working Conditions
4.1 7 Emergency Inspections after Extreme Weather
Additional required after typhoons/storms:
Laser retest of track leveling
Electrical cabinet waterproof seal test (water damage detection with dry paper towels)
Validation of effectiveness of windproof anchoring device
Case: 2023 A terminal in Zhuhai did not check the track after typhoon “Taili”, resulting in the gantry crane derailed and tilted.
4.2 “Rehabilitation Program” after overload operation
If accidentally overloaded by more than 10%:
Immediately carry out non-destructive testing of the whole structure
Run unloaded for 1 hour to observe abnormalities
Contact the manufacturer for stress relief (Huada offers remote diagnostic services).
5. Tool Revolution
5.1 Low-cost and efficient toolkit (budget <5000 RMB)
Wire Rope Flaw Detector: Zhengzhou-made HD-RT3 (accuracy ± 0.2mm, priced at 2980 RMB)
Vibration analysis APP: VibScanner (analyze bearing faults through cell phone microphone)
Huada Intelligent Monitoring System: real-time warning + automatic generation of inspection reports (click to apply for a free trial)
Thermal Imaging Camera: FLIR E5-XT (quickly locate electrical over-hot spots, 8 hours of endurance)
Sixth, avoid the pit guide: blood and tears lessons summarized
6.1 Frequency Misconceptions
Data show that: the implementation of the monthly inspection of the equipment, three years after the maintenance costs increased by 240%.
6.2 Method Mistake of Gantry Crane
In 2021, a steel plant in Changsha failed to measure the torque of bolts, resulting in one death and three injuries due to the fall of a beam.
7. Expert Advice: The Secret to Extending the Golden Week
7.1 Dynamic maintenance program template
Automatically adjust the inspection frequency according to the intensity of use:
Formula: Actual Inspection Cycle = Standard Cycle × (Rated Load/Actual Average Load)
Huada provides many special services for 20 ton gantry cranes. If you need it, please
contact Huada directly to provide you with comprehensive and professional services!
