Valve operator assembly with freewheel and axial friction means

Valve comprising a valve body, a valve translating member axially moveable and a valve operator assembly for valve comprising a valve body and a valve translating member axially moveable, the assembly comprising a housing adapted to be mounted on the valve, an input member rotatably mounted with respect to said housing, and a transmission mechanism comprising a translating element adapted to be connected to the valve translating member of the valve and a rotating element connected to the input member, said transmission mechanism being adapted to convert applied rotation of the input member into axial translation of said translating element, characterized in that the assembly further comprises a locking mechanism provided with a casing mounted on the transmission mechanism and/or the housing, with at least one freewheel comprising a plurality of locking members mounted in radial contact with the transmission mechanism and with the casing, and with friction means axially disposed between said casing and the housing and mounted in axial contact with said housing, the friction means, the freewheel and the casing cooperating together to lock the transmission mechanism with the housing in a static position of said assembly.