The real-time tension monitoring of wire ropes is a universal way to judge whether the hoist is overloaded in the special working environment of the coal mine. However, due to the strong drafts, unevenness of guide and flexible vibration of wire ropes, it is a challenge to monitor the tension with high accuracy. For this purpose, a new type of acoustic filtering sensor is designed in this study. To adapt to the violent vibration during the monitoring process, a structure with a cylindrical cavity and a narrow gap is designed in the sensor. The coupling between the internal fluid and sensor structure can greatly absorb the vibration energy. With the view of optimizing the filtering performance of the sensor, the influences on the filtering characteristics are presented and analyzed through employing different structural and acoustic parameters in simulations. Finally, acoustic filtering sensor prototypes based on optimized parameters are calibrated and tested in a real coal mine. The results have revealed that our acoustic filtering sensor can not only address the deficiencies of current pressure sensors in coal mining and achieve tension monitoring in real-time, but is also able to diagnose and forecast the occurrence of tension imbalance accidents.

Wire rope tension is one of the vital monitoring parameters for the hoister system, which seriously influence mine coal safety production. However, wire ropes endure vibration and shock in lifting process of multi-rope friction hoisters in coal mine, which interferes with measurement of wire rope tension and lifting load seriously. Aimed to the difficulty of monitoring wire rope tension, this paper put forward a new measurement method of wire rope tension by transferring wire rope tension measurement to pressure measurement, which improves the measurement safety and avoids the safety hazards of adopting pull sensor in series with wire rope, and this paper also designed an acoustic filtering sensor which uses the filtering characteristic of acoustic cavity to eliminate the effect of vibration and shock in wire rope tension measurement. Meanwhile, a novel wire rope tension monitoring device of multi-rope friction hoister is presented based on the proposed measurement method and sensor, which can measure each wire rope tension in the lifting process, display the cage load and monitor the fault of wire rope tension unbalance. Real-time and accurate wire rope tension measurement is realized. By comparing the signals measured by the common sensor and the acoustic filtering sensor, the influence of vibration and shock on the multi-ropes tension measurement is eliminated, and the fault of wire rope tension unbalance can be monitored. This advanced tension monitoring device is of great significance to the safety of coal mine production. in 2003. Now she works at China University of Mining and Technology. Her current research interests include electromechanical system design, fluid mechanics, fluid transport machinery and robotic mechanics. Jianpu Da is a Master student. His current research interest is mechanical design and theory. Xiaoguang Zhang received Ph.D. degree in detection technology and automatic equipment major, East China University of Science and Technology, Shanghai, China, in 2003. Now he works at China University of Mining and Technology. His current research interests include intelligent information processing, electromechanical monitoring and fault diagnosis and sensing technology and instrumentation.Mengfang Han is a postgraduate student. His research interest is mechanical fault diagnosis.Tingting Xia is a Master student. Her current research interest is measurement control technology and instrument.

A novel mechanical design of the broken rope protection device is proposed to enhance the safety performances of the overhead manned equipment. According to the operating characteristics and functional requirements of the overhead manned equipment, a three-dimensional mechanical model of the broken rope protection device was redesigned. Based on the known parameters of the mechanical model, the stress and strength of the main components are readjusted using the statics characteristics of finite element analysis. To ensure the reliability of the control system of the broken rope protection device, the process of people's falling, the response performance of the tension sensor, and the signal extraction of the broken rope are analyzed under different loading and unloading speeds. The working principle of the broken rope protection device is expounded in detail. The experimental results showed that better effect is obtained by the new broken rope protection device, which is characterized by good durability, low investment, and high reliability.