A servo-assisted butterfly valve provided with a flat leaf spring and a spiral spring to establish the limp-home position

A servo-assisted butterfly valve (1) comprising a valve body (2), a valve seat (4) formed in the valve body (2), a butterfly disc (5) adapted to engage the valve seat (4), a shaft (6) on which the butterfly disc (5) is keyed, an electric motor (3) coupled to the shaft (6) by means of at least one toothed wheel (17) provided with a projection (45), a spiral return spring (35) adapted to rotate the butterfly disc (5) towards the closed position, and an opposing spring (36) adapted to rotate the butterfly disc (5) towards a limp-home position defined by an abutment body (37) against the action of the return spring (35); the opposing spring (36) is a flat leaf spring and is mounted on a moving member (40) which is mounted coaxially and idly on the shaft (6) and comprises a projection (42) adapted to engage in abutment against the abutment body (37), a first end (43) of the opposing spring (36) being free and adapted to come into contact with the projection (45) of the toothed wheel (17) during the rotation of this toothed wheel (17).