Abstract: A system for reducing maintenance frequency for bolts and nuts of a wind turbine comprises a plurality of fastening units, a PC data collector, a server and a terminal. The fastening unit has a bolt sequentially penetrates through a lower spacer, a sensor, an upper spacer, a wind turbine parts, a threaded ring, and a washer, and then a nut is engaged and tightly fastened on the bolt. With the fastening units, the system applied to the wind turbine is configured to create a double nut locking system thereby maintaining a preload tension force of the bolt in a safety operation range. Also, through the monitoring system including the sensor connected to the terminal through the PLC data collector and the server, a user can receive the real-time monitoring data of the preload tension force of the bolt to maintain and repair the wind turbine efficiently thereby preventing accidents.

Abstract: A counting mechanism of a hydraulic tightening device that includes an oil input/output mechanism and a counting mechanism, wherein the counting mechanism includes a counter, a piston sealing, a driving piston, a spring, a spring cover, a counting unit, a piston restricting unit, a main body seal, a lower cover, a bolt and a restricting unit. The oil input/output mechanism is connected to the hydraulic tightening device through the counting mechanism, and once the hydraulic oil passes through the oil input/output mechanism, the counting mechanism automatically records as the hydraulic tightening device performs one more time.