TURNBUCKLE DAMPENING LINKS
Technical Field This invention relates to torque shaft assemblies for moving an array of adjustable members to rotate variable stator vanes in a gas turbine engine. More particularly, it relates to torque shaft assemblies with turnbuckles or rods connecting the torque shaft to unison rings used to rotate the variable stator vanes. Background Information Some gas turbine engines with variable stator vanes (VSV) include a torque shaft assembly associated with an actuator. Such an assembly enables and coordinates movement of a plurality of stages of stator vanes responsive to controlled, changing engine conditions by way of crank arms connected to a unison ring for varying the angle of the vanes in each stage. A torque shaft is used to actuate the variable stator vane system of the high-pressure compressors on engines such as the General Electric LM2500+ engine. Generally, a torque shaft actuation system is advantageous in providing flexibility in stage to stage (non-linear) VSV scheduling. Examples of gas turbine engines including axial flow compressors having variable stator mechanisms are disclosed in U.S. Pat. Nos. 2,858,062, 2,933,235, and 5,281,087. Examples of torque shaft assemblies for VSVs are disclosed in U.S. Pat. Nos. 4,890,977, 6,457,937, and 6,551,057. Torque shafts are used to actuate unison rings through adjustable length push rods or turnbuckles. Rod ends of the rods are pivotably connected to clevises mounted on torque shaft. Rolling motion caused by engine vibration may lead to premature wear of the rod ends and clevises. A torque shaft assembly for actuating devices on a gas turbine engine, the assembly including two or more adjustable length turnbuckles linked to devices, an elastomeric dampening link including two or more interconnected dampening bushings mounted around corresponding ones of the two or more adjustable length turnbuckles, and the elastomeric dampening link including at least one bar connecting adjacent ones of the dampening bushings. A clamp with a clamping band may be clamped around each of the dampening bushings. The bar may be in tension between the dampening bushings. The clamping band may be received in an annular slot or groove in each of the dampening bushings. At least one of the dampening bushings may be circumscribed about a bushing centerline, be substantially solid, and have a rectangular slot extending radially inwardly from an annular surface of each of the dampening bushings. Each one of the turnbuckles may include a rod disposed in a corresponding one of the dampening bushings. The rod may have a distal hollow internally threaded first end, a first eyelet mounted on a first externally threaded shank, and the first externally threaded shank adjustably screwed into the internally threaded first end. At least one of the dampening bushings may be circumscribed about a bushing centerline, be substantially solid, and have a rectangular slot extending radially inwardly from an annular surface of each of the dampening bushings. The rod may have a six sided surface with two opposite sides slidingly engaging and snugly fit in the slot. A clamp with a clamping band may be clamped around each of the dampening bushings. A variable stator vane actuation apparatus includes a compressor casing surrounding and supporting two or more rows of variable stator vanes, a variable stator vane dampened linkage including two or more unison ring assemblies mounted exterior to the compressor casing and operable for varying the angle of variable stator vanes in corresponding ones of the rows, two or more adjustable length turnbuckles linking corresponding ones of the two or more unison ring assemblies to a torque shaft mounted on the compressor casing, an elastomeric dampening link including two or more interconnected dampening bushings mounted around corresponding ones of the two or more adjustable length turnbuckles, and the elastomeric dampening link including at least one bar connecting adjacent ones of the dampening bushings. The apparatus may further include first eyelets pivotably connected to first clevises mounted on the torque shaft with first clevis ball joints, the second eyelets pivotably connected to second clevises mounted to unison rings of the two or more unison ring assemblies with second clevis ball joints, and first and second spherical bushings centered and disposed in the first and second eyelets respectively. The apparatus may further include vane crank arms connecting the variable stator vanes to the unison rings, the second clevises mounted on bridges of the unison rings, each of the turnbuckles including a rod disposed in a corresponding one of the dampening bushings and having distal hollow internally threaded first and second ends, first and second eyelets attached to or mounted on first and second externally threaded shanks respectively, the first and second externally threaded shanks adjustably screwed into the internally threaded first and second ends respectively, The first eyelets pivotably connected to first clevises mounted on the torque shaft with first clevis ball joints. The second eyelets pivotably connected to second clevises mounted to unison rings of the two or more unison ring assemblies with second clevis ball joints. The first and second spherical bushings are centered and disposed in the first and second eyelets respectively. The compressor 12 includes a variable inlet guide vane 29 followed by a plurality of circumferentially spaced rotor blades 28 and variable stator vanes (VSV) 30 disposed in several rows 31. Illustrated are seven rows of the rotor blades 28 and seven rows 31 of the variable stator vanes 30 surrounded by a compressor casing 32. Stator vanes 30 direct inlet airflow 24 at the desired angle into the rotor blades 28. Variable inlet guide vane 29 and variable stator vanes 30 direct inlet airflow 24 into rotor blades 28 at various angles depending on engine operating conditions to improve compressor stall margin and to improve fuel efficiency of the engine. An engine control 50, such as a mechanical or digital electronic control, is used to control operation of the engine 10 including the varying of the VSVs 30. Illustrated in Referring to Referring to Referring more particularly to Referring to Referring to The present invention has been described in connection with specific examples, embodiments, materials, etc. However, it should be understood that they are intended to be representative of, rather than in any way limiting on, its scope. Those skilled in the various arts involved will understand that the invention is capable of variations and modifications without departing from the scope of the appended claims. An elastomeric dampening link including two or more interconnected dampening bushings mounted around corresponding ones of two or more adjustable length turnbuckles linked to devices and elastomeric dampening link includes at least one bar connecting adjacent ones of the dampening bushings. Clamping bands of clamp may be clamped around each of the dampening bushings. Bar may be in tension between the dampening bushings. Each of the turnbuckles may include a rod disposed in a corresponding one of the dampening bushings and having distal hollow internally threaded first end, first eyelet mounted on the first externally threaded shank adjustably screwed into internally threaded first end. One of the bushings may be substantially solid, have a rectangular slot extending inwardly from an annular surface of bushing, and the rod may have six sided surface with two opposite sides slidingly engaging and fitting snugly in the slot. Turnbuckles and links may be used to actuate variable stator vanes. 1. A torque shaft assembly for actuating devices on a gas turbine engine, the assembly comprising:
two or more adjustable length turnbuckles linked to devices, an elastomeric dampening link including two or more interconnected dampening bushings mounted around corresponding ones of the two or more adjustable length turnbuckles, and the elastomeric dampening link including at least one bar connecting adjacent ones of the dampening bushings. 2. The assembly as claimed in 3. The assembly as claimed in 4. The assembly as claimed in 5. An assembly as claimed in each of the turnbuckles including a rod disposed in a corresponding one of the dampening bushings and having distal hollow internally threaded first end, a first eyelet mounted on a first externally threaded shank, and the first externally threaded shank adjustably screwed into the internally threaded first end. 6. The assembly as claimed in 7. The assembly as claimed in 8. The assembly as claimed in at least one of the dampening bushings circumscribed about a bushing centerline, being substantially solid, and having a rectangular slot extending radially inwardly from an annular surface of each of the dampening bushings, the rod including a six sided surface with two opposite sides slidingly engaging and fitting snugly in the slot, and clamps with clamping bands clamped around the dampening bushings. 9. The assembly as claimed in 10. A variable stator vane actuation apparatus comprising:
a compressor casing surrounding and supporting two or more rows of variable stator vanes, a variable stator vane dampened linkage including two or more unison ring assemblies mounted exterior to the compressor casing and operable for varying the angle of variable stator vanes in corresponding ones of the rows, two or more adjustable length turnbuckles linking corresponding ones of the two or more unison ring assemblies to a torque shaft mounted on the compressor casing, an elastomeric dampening link including two or more interconnected dampening bushings mounted around corresponding ones of the two or more adjustable length turnbuckles, and the elastomeric dampening link including at least one bar connecting adjacent ones of the dampening bushings. 11. The apparatus as claimed in 12. The apparatus as claimed in 13. The apparatus as claimed in 14. The apparatus as claimed in each of the turnbuckles including a rod disposed in a corresponding one of the dampening bushings and having distal hollow internally threaded first and second ends, first and second eyelets attached to or mounted on first and second externally threaded shanks respectively, and the first and second externally threaded shanks adjustably screwed into the internally threaded first and second ends respectively. 15. The apparatus as claimed in the first eyelets pivotably connected to first clevises mounted on the torque shaft with first clevis ball joints, the second eyelets pivotably connected to second clevises mounted to unison rings of the two or more unison ring assemblies with second clevis ball joints, and first and second spherical bushings centered and disposed in the first and second eyelets respectively. 16. The apparatus as claimed in 17. The apparatus as claimed in 18. The apparatus as claimed in 19. The apparatus as claimed in at least one of the dampening bushings circumscribed about a bushing centerline, being substantially solid, and having a rectangular slot extending radially inwardly from an annular surface of each of the dampening bushings, the rod including a six sided surface with two opposite sides slidingly engaging and fitting snugly in the slot, and a clamp with a clamping band clamped around each of the dampening bushings. 20. The apparatus as claimed in vane crank arms connecting the variable stator vanes to the unison rings, the second clevises mounted on bridges of the unison rings, each of the turnbuckles including a rod disposed in a corresponding one of the dampening bushings and having distal hollow internally threaded first and second ends, first and second eyelets attached to or mounted on first and second externally threaded shanks respectively, the first and second externally threaded shanks adjustably screwed into the internally threaded first and second ends respectively, the first eyelets pivotably connected to first clevises mounted on the torque shaft with first clevis ball joints, the second eyelets pivotably connected to second clevises mounted to unison rings of the two or more unison ring assemblies with second clevis ball joints, and first and second spherical bushings centered and disposed in the first and second eyelets respectively.BACKGROUND OF THE INVENTION
SUMMARY OF THE INVENTION
BRIEF DESCRIPTION OF THE DRAWINGS
DETAILED DESCRIPTION OF THE INVENTION








