VARIABLE VANE ASSEMBLY FOR A GAS TURBINE ENGINE HAVING AN INCREMENTALLY ROTATABLE BUSHING

摘要

A variable vane assembly (64) for a gas turbine engine (10) having a casing (68), including: a variable vane (70) including a platform (74) and a vane stem (72) extending outwardly from the platform (74); a bushing (92) surrounding the vane stem (72); a lever (78) for moving the vane (70) between a closed position a nd an open position; and, a mechanism (100) for incrementally rotating the bushing (92) to a new circumferential position with respect to the vane stem (72) as the vane (70) is cycled each time between the closed and open positions. The bushing (92) further includes a plurality of stepped portions (104) circumferentially spaced abou t a top surface (102) of the bushing (92) and a plurality of indented stops (116) circumferentially spaced about a side surface (114) of the bushing (92). A plurality of pawls (112) is associated with the lever (78), wherein the pawls (112) engag e one of the stepped portions (104) of the bushing top surface (102) to cause the bushing (92) to rotate in a first direction a predetermined amount as the vane (70) moves from the closed position to the open position. At least one pawl (118) is also associated with the casing (68) which engages one of the indented stops (116) of the bushing side surface (114) to prevent the bushing (92) from rotating in a second directio n opposite the first direction more than a second predetermined amount as the vane (70) moves from the open position to the closed position.