| 摘要 |
PROBLEM TO BE SOLVED: To surely carry out locking and lock releasing with a simple structure. SOLUTION: To a hydraulic cylinder 24 to rotate a steering knuckle 21L, a lock mechanism 25 composed by including a lock piston 25a sliding about vertically to the peripheral wall of a piston 24d, and a spring to energize the lock piston 25a in the direction of the piston 24d, is installed. An operation oil is fed to the oil room 26L of the hydraulic cylinder 24, through an operation control valve 32L which is opened when the oil pressure fed to the oil room 25d is made more than a specific pressure, from the oil room 25d to release the lock of the steering knuckle 21L. In the locking condition, the front end of the lock piston 25a is fitted to a recessed groove formed on the peripheral wall of the piston 24d, while in the lock releasing condition, the front end of the lock piston 25a is removed for the recessed groove against the energizing force of the spring 25b. |
