Stator vane actuating mechanism

• US 3,873,230 A
• Filed: 04/10/1974
• Issued: 03/25/1975
• Est. Priority Date: 04/10/1974
• Status: Expired due to Term

• Current Assignee: Frederick Mathew Pendoley, James Reynolds Norris
• Original Assignee: Frederick Mathew Pendoley, James Reynolds Norris
• Inventors: Norris, James Reynolds, Pendoley, Frederick Mathew
• Primary Examiner(s): Raduazo, Henry F.
• Application Number:
  US05/459,836
• Time in Patent Office: 349 Days
• Field of Search: 415/149,162,23,160
• US Class Current: 415/162
• CPC Class Codes: F01D 17/16 by means of nozzle vanes
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

In a vane actuation system including several actuated stages, unison rings for pairs of stages are actuated in opposite directions. The bell-cranks for actuating the unison rings are all connected to a common carrier wherein the oppositely directed loads substantially balance out so that only the difference is transmitted into the engine casing. The bell-crank actuator is also mounted on the common carrier and therefore none of its loads are transmitted into the engine casing. The common carrier is substantially isolated from the casing by support members which permit the casing to grow and deflect without inducing large stresses in the common carrier.

Claims

1. In an axial flow gas turbine engine a stator vane actuation system comprising:

an annular casing;

a plurality of stages of rotatably mounted stator vanes disposed within said casing, including at least one pair of balanced stages;

a plurality of first actuating arms connected to the vanes of a first stage of each of said pairs and extending rearwardly therefrom;

a plurality of second actuating arms connected to the vanes of a second stage of each of said pairs and extending forwardly therefrom;

a first unison ring for each of said pairs surrounding said casing and disposed rearwardly of the vanes of said first stage of each of said pairs, said first actuating arms being connected thereto;

a second unison ring for each of said pairs surrounding said casing and disposed forwardly of the vanes of said second stage of each of said pairs, said second actuating arms being connected thereto;

a bell-crank support assembly including substantially axially extending bell-crank carrier means, said support assembly also including casing connecting means secured to said carrier means and to said casing, and adapted to substantially isolate said carrier means from deflection and axial growth of said casing;

bell-crank means including a pair of bell-cranK arms for each of said pairs of stages, said arms being pivotally connected to said carrier means, one of said pair of bell-crank arms extending forwardly of its pivot point and the other of said pair of bell-crank arms extending rearwardly of its pivot point, one of said pair of bell-crank arms being connected to said first unison ring and the other of said pair of bell-crank arms being connected to said second unison ring; and

actuation means mounted entirely on said bell-crank support assembly and connected to said bell-crank means and adapted to simultaneously rotate said pairs of bell-crank arms in the same direction thereby rotating said first and second unison rings of each of said pairs of stages in opposite directions to balance the reaction forces transmitted into said carrier means through each of said pairs of bell-crank arms and to effectuate rotation in the same direction of the vanes of each of said pairs of stages.

2. The stator vane actuation system according to claim 1 wherein the stages of each of said pairs of stages are adjacent stages.

3. The stator vane actuation system according to claim 1 wherein at least one pair of bell-crank arms is pivotally connected to said carrier means about a common axis.

4. The stator vane actuation system according to claim 1 wherein not more than one of said stages of rotatably mounted stator vanes is an unpaired stage.

5. The stator vane actuation system according to claim 4 wherein said casing connecting means includes forward support means and rearward support means one of said support means being substantially rigid and the other permitting relative movement between said casing and said carrier means thereby substantially isolating said carrier means from said casing, said forward and rearward support means being the only load paths from said carrier means into said casing.