Guide vane operating mechanism for hydraulic machine

Claim 1

A guide vane operating mechanism in a hydraulic machine having a main shaft; a volute casing surrounding said main shaft and having an inner peripheral wall, said volute casing being imbedded in a concrete structure having an inner wall defining an inside space; a runner integrally incorporated with said main shaft and disposed within said inside space; and guide vanes lying along said inner peripheral wall of said volute casing for guiding water led from said volute casing to said runner at an optimum angle for rotation of said inner runner; the guide vane operating mechanism comprising: a plate-like rotatable guide ring rotatably arranged around said main shaft within said inner space and having an outer peripheral edge section defining therein a bearing hole; a guide vane driving mechanism for linkage between said guide vanes and said guide ring to drive said guide vanes in a range of between fully-opened and fully-closed positions in association with rotation of said guide ring; at least one servo motor having a gear end stationarily secured to said inner wall of said concrete structure and having a reciprocating piston rod secured thereto with a rod end fitting formed therein with a bearing hole, for rotating said guide ring, said piston rod reciprocating slightly above said guide ring in a direction parallel to a line tangential to said outer peripheral edge section of said guide ring; and an eccentric pin formed of two columnar bodies which are integrally incorporated together in a staggered manner so that one of said columnar bodies provides one end shaft part of said eccentric pin while the other of said columnar bodies provides the other end shaft part of said eccentric pin for connecting said rod end fitting with said guide ring such that said one end shaft part of said eccentric pin is rotatably fitted in said bearing hole in said rod end fitting while the other end shaft part of said eccentric pin is rotatably fitted in said bearing hole in said outer peripheral edge section of said guide ring.