To provide a locking device for a directly operated butterfly valve, which can lock a posture of a valve plate by elastic engagement, release and set the locking mechanism during operation of the valve, and operate the valve with single operation.
A disc 21 which is elstically rotated unitedly with an operation shaft 11 and pressed down and energized by means of a belleville spring 22 is arranged on the operation shaft 11 for opening and closing a valve plate 4 of a butterfly valve, so as to be faced to a fixed portion on the side of a valve main body 1. A plurality of recessions are formed on one of the disc 21 and the fixed poriton on the valve main body 1 side opposed to each other, spaced with specified intevals on the same circumference around an axis of the operation shaft 11. On the other of the opposed surfaces, balls 23 corresponding to the recessions in number and arragement are formed so as to elastically and disengageably engage with the recessions. The recessions and the balls 23 are elastically engaged and disengaged with each other during operation of a the valve.
KOIWA HIROSHI
SHIMIZU HIROSHI
YAMADA MASAHIRO
OSAKA GAS CO LTD