PURPOSE: To make a blade impossible to open/close during turning an engine and further to make a vehicle impossible to in a condition of fixing the blade lifted by preventing the engine from acting during lifting the blade while locking opening/closing the blade in the case of turning on an engine key switch.

CONSTITUTION: A hydraulic cylinder for vertically turning a blade of a wind vehicle is actuated by a hydraulic unit 24 with a battery 22 serving as a power source. A relay switch 30 is connected to right/left push button switches 26, 28 through a double wire connecting terminal 42 and on the other hand connected to an engine key switch circuit. The push button switches 26, 28 are connected to the hydraulic unit 24 through the double wire connecting terminal 42 and male/female wire connecting terminals 44, 46. A limit switch 50 is mounted between a front wall or rear door top part and a blade lower surface, to connect a starter lock relay 52 to the limit switch 50 by electrical wiring. In this way, during actuating an engine, the blade can not be opened/closed.