Variable vane lever arm
A vane arm has: a first end and a second end. A shank extends between the first end and the second end and has a first face and a second face. A first hole is in the shank proximate the first end and a second hole is in the shank proximate the second end. A tab projects distally from the shank proximate the second end and has: a bend; and a distal portion distally of the bend and projecting back toward the first end and less than fully overlapping the second hole, if at all.
1 . A vane arm comprising:
a first end and a second end;
a shank extending between the first end and the second end and having a first face and a second face;
a first hole in the shank proximate the first end;
a second hole in the shank proximate the second end; and
a tab projecting distally from the shank proximate the second end and having:
a bend; and
a distal portion distally of the bend projecting back toward the first end and less than fully overlapping the second hole, if at all.
2 . The vane arm of claim 1 further comprising:
a third hole closer to the second hole than to the first hole.
3 . The vane arm of claim 2 wherein:
the first, second, and third holes are in a single metallic piece.
4 . The vane arm of claim 2 further comprising:
a fourth hole between the third hole and the first hole and having a length between the first and second holes at least three times a width transverse thereto.
5 . A vane assembly including the vane arm of claim 1 and further comprising a vane having an airfoil and a shaft protruding from an end of the airfoil, wherein:
the vane shaft extends through the second hole;
the vane shaft has a side facet abutting an end of the tab distal portion; and
a nut holds the vane arm to the shaft compressed between the nut and a shoulder of the vane shaft.
6 . The vane assembly of claim 5 wherein:
a tab washer is between the nut and the vane arm and has a tab received in a third hole in the vane arm.
7 . The vane assembly of claim 5 wherein:
the vane has a radially-extending surface at a proximal end of the facet.
8 . The vane assembly of claim 5 further comprising:
a pin mounted in and protruding from the first hole.
9 . A vane stage comprising a plurality of vane assemblies of claim 5 and further comprising:
a synchronizing ring coupled to each vane arm and having an axis; and
for each vane assembly one or more bearings mounting the vane for rotation about an axis of the vane wherein, rotation of the synchronizing ring about its axis rotates each vane about its respective axis.
10 . A method for using the vane arm of claim 1 , the method comprising:
installing the arm to a vane so that:
a shaft of the vane extending from an end of an airfoil of the vane passes through the second hole; and
an end of the tab distal portion abuts a side facet of the vane shaft; and
installing a nut to a threaded portion of the shaft to hold the vane arm to the shaft.
11 . The method of claim 10 further comprising:
installing a pin to the first hole.
12 . The method of claim 11 wherein:
the method is performed with a plurality of vane arms and the respective pins are mounted to a shared synchronizing ring.
13 . The vane arm of claim 4 further comprising:
the fourth hole spans at least 30 percent of an overall length of the vane arm.
14 . The vane arm of claim 4 further comprising:
the fourth hole spans 30 percent to 45 percent of an overall length of the vane arm.
15 . The vane arm of claim 4 further comprising:
the fourth hole width is 10 percent to 30 percent of said fourth hole length.
16 . The vane arm of claim 4 wherein:
the first and third holes are circular in footprint.