Valve opening and closing mechanism in engines

摘要

When a valve 10 is opened, a locking ball 8 moves upward with respect to a rocker arm 3 and the locking ball is located between the rocker arm 3 and a push rod 5. The push rod 5 moves downward integral with the rocker arm 3 in a condition the push rod 5 is locked. When a valve 10 is closed, the locking ball 8 moves downward with respect to the rocker arm 3 and the push rod 5 is placed in unlocked condition. A retaining member 3A in the rocker arm 3 contacts the circlip 9 and the push rod 5 moves upward. By this construction, it becomes possible to eliminate adjustment work of tappet clearances and also unfavorable conditions caused by adjustment work of tappet clearances.