| 摘要 |
PROBLEM TO BE SOLVED: To quickly and easily switch between a fastened state and a released state. SOLUTION: As shown in (a), flanges 21 and 22 are fastened between a bolt head 24 of a fastening bolt 20 and a nut 30 screwed onto a thread part 25 through spherical washers 31, 32. A cavity part 26 is formed in the inside of a shaft 23 of the fastening bolt 20, and when hydraulic oil is supplied from a supply pressurized oil port 29 of a plug member 28 to increase the pressure in the inside of the cavity part 26, the shaft 23 is lengthened to obtain a released state as indicated in (b). In the released state, a fastened state between the nut 30 and the fastening bolt 20 becomes free, and nut 30 can be easily removed by hand even when the fastening bolt 20 is large-sized. When the oil pressure applied to the cavity part 26 is released in accordance with the lengths of gaps 33, 34, the fastened state as shown in (a) is obtained, and fastening force can be adjusted by means of the gaps 33, 34. |
