The National Bridge Gantry Crane Quality Inspection Center advances safety brake inspection and testing into the "e-era."

The computer program automatically calculates the required moment of inertia and configures it by moving the inertia disk via the control panel. Once in the control room, the test system is initiated; after the testing is complete, the system generates test curves and a detailed test report automatically. After conducting five tests, technicians analyze the valid data and prepare the final test report. On July 23, the comprehensive performance testing system for crane safety brakes—developed by the technical team at the National Bridge Gantry Crane Quality Inspection Center (referred to as "National Crane Center" hereafter)—left a strong impression during a dynamic braking torque test on an SB400 hydraulic clamp-disc brake model conducted for a particular company.

The safety brake, also known as the low-speed shaft protection brake, is a safety device that has garnered significant attention both domestically and internationally. Its performance and reliability are critically important to crane operation safety, as it helps prevent catastrophic failures such as shaft breakage, key shearing in couplings, or gear tooth damage in the gearbox—failures that could otherwise lead to the accidental dropping of suspended loads. In China, the newly revised standards, design codes, and safety regulations for lifting machinery now include clear requirements for low-speed shaft safety protection brakes.

Conducting product testing and safety oversight for safety brakes is a critical issue for relevant safety supervision and certification authorities. For a long time, China has faced a "regulatory and testing vacuum" when it comes to low-speed, high-torque safety brakes. Due to the lack of specialized inspection and testing equipment, very few professional testing organizations possess the capability to perform type tests or inspections on safety brakes. "Brake test benches are highly specialized, non-standardized products—there are no dedicated manufacturers, nor do industry standards or specific design guidelines exist," explains Dr. Su Wensheng, a technical expert at the National Institute of Safety Engineering. "Even internationally, there isn’t a dedicated safety brake testing system available."

"Guoqi Center, as a national-level inspection agency, should take responsibility and ensure the high-quality completion of safety protection device inspection and testing tasks," believes Sun Xiaowei, a researcher-level senior engineer and director of the Wuxi Branch Institute. As early as 2011, the institute had already submitted the research project titled "Feasibility Study on the Comprehensive Performance Testing System for Safety Brakes" to the General Administration of Quality Supervision, Inspection, and Quarantine—and the project was subsequently approved, paving the way for a feasibility study into the technical principles underlying the safety brake testing system.

"From market research and understanding enterprise needs, to innovating on technical principles, developing groundbreaking and optimized R&D solutions, and finally conducting rigorous testing and validation—this entire process of developing the complete device took nearly 1 year and 10 months," said Dr. Su Wensheng. "The device can now measure a maximum dynamic braking torque of up to 400,000 N·m, marking a significant leap forward in safety brake performance testing into the 'e-era.' It enables automated safety interlocks, real-time online monitoring, fault alerts, data querying and output, as well as fully automated operational processes." This comprehensive safety brake performance testing system makes it possible to carry out type tests and inspections for safety brakes, catering specifically to industries such as ports, mining, and wind power. It is designed to meet the demands of type testing, supervisory sampling, and product inspections for large and even ultra-large safety brakes—including hydraulic caliper-disc brakes, electromagnetic caliper-disc brakes, and pneumatic caliper-disc brakes. According to the introduction, the testing system can simulate operating conditions where the braking torque exceeds 400,000 N·m, with brake disc diameters of at least 3,150 mm and rotational inertia exceeding 200,000 kg·m² (with the high-speed shaft alone reaching 520 kg·m²).

"Currently, the Guoqi Center boasts the most comprehensive range of ‘braking’ performance testing capabilities in China, equipped with advanced test facilities including an industrial brake dynamometer, static and dynamic test benches for safety brakes, a test rig for wind-resistant and anti-slip braking systems, a brake motor test bench, and a dynamic torque testing station for brake motors—among other specialized equipment. Moving forward, the Guoqi Center plans to apply for designation as a public technical service platform for braking performance testing, further enhancing its ability to serve the nationwide market for brake product performance evaluation," said Sun Xiaowei. *China Quality Daily*