LINKAGE APPARATUS HAVING A LOW PROFILE ASYMMETRICAL HEAD
A high-cycle, short range-of-motion linkage apparatus is provided for actuating a positioning device. The linkage apparatus includes a pivot member having a head portion configured to receive by plastic deformation a bearing assembly therein. The head portion defines a bore therein having a substantially cylindrical inner surface that defines an inner diameter having a first center point. The head portion further defines a truncated arcuate outer surface, a portion of which defines a radius of curvature and a second center point. A stem having a central axis extends from the pivot member along the central axis in a first direction. The second center point is offset from the first center point in the first direction and a distance between the first center point and the second center point, measured along the central axis, is in the range of up to about 33% of the radius of curvature.
1 . A linkage apparatus for actuation of a positioning device, the linkage apparatus comprising:
a pivot member having a head portion configured to receive by plastic deformation a bearing assembly therein, the head portion defining a bore therein having a substantially cylindrical inner surface that defines an inner diameter having a first center point, the head portion further defining a truncated arcuate outer surface, a portion of which defines a radius of curvature and a second center point;
a stem having a central axis, the stem extending from the pivot member along the central axis in a first direction; and
the second center point is offset from the first center point in the first direction and a distance between the first center point and the second center point, measured along the central axis, is up to about 33% of the radius of curvature.
2 . The linkage apparatus of claim 1 wherein the distance between the first center point and the second center point is from about 5% to about 25% of the radius of curvature.
3 . The linkage apparatus of claim 1 wherein the linkage apparatus is fabricated from a martensitic precipitation/age-hardening stainless steel alloy.
4 . The linkage apparatus of claim 1 wherein the linkage apparatus is fabricated from PH 13-8.
5 . The linkage apparatus of claim 1 wherein the linkage apparatus is configured to be operable with a turbofan engine fan bleed air system.
6 . The linkage apparatus of claim 5 wherein the linkage apparatus is configured to be operable with a variable bypass vane actuator assembly.
7 . The linkage apparatus of claim 1 further comprising the head portion plastically deformed around a bearing assembly.
8 . The linkage apparatus of claim 7 wherein the bearing assembly comprises:
an inner member having an outer engagement surface and a bore extending at least partway therethrough;
an outer member positioned at least partially around the inner member, the outer member having an inner engagement surface contoured to a shape complementary to the outer engagement surface of the inner member; and
a self-lubricating liner disposed between the inner engagement surface of the outer member and the outer engagement surface of the inner member.
9 . The linkage apparatus of claim 8 wherein the liner of the bearing assembly comprises a polytetrafluoroethylene (“PTFE”) bonded with a thermoset resin.
10 . The linkage apparatus of claim 8 wherein the liner of the bearing assembly comprises a perfluorooctanoic acid (“PFOA”) polytetrafluoroethylene (“PTFE”) bonded with a polyimide resin system.
11 . The linkage apparatus of claim 8 wherein the liner of the bearing assembly comprises a Teflon® liner containing no PFOA.
12 . The linkage apparatus of claim 8 wherein the liner of the bearing assembly comprises a Teflon® liner containing PFOA.
13 . A linkage apparatus for actuation of a positioning device, the linkage apparatus comprising:
a positioning member defining a first end, a second end, and a central axis therethrough;
a pivot member defined at the first end of the positioning member and having a head portion configured to receive by plastic deformation a bearing assembly therein, the head portion defining a bore therein having a substantially cylindrical inner surface that defines an inner diameter having a first center point, the head portion further defining a truncated arcuate outer surface, a portion of which defines a radius of curvature and a second center point;
a stem extending from the pivot member along the central axis of the positioning member in a first direction;
a coupling member defined at the second end of the positioning member for coupling the positioning member to a structural member; and
the second center point is offset from the first center point in the first direction and a distance between the first center point and the second center point, measured along the central axis, is in the range of up to about 33% of the radius of curvature.
14 . The linkage apparatus of claim 13 wherein the linkage apparatus is fabricated from PH 13-8.
15 . The linkage apparatus of claim 13 further comprising the head portion plastically deformed around a bearing assembly.
16 . The linkage apparatus of claim 13 wherein the bearing assembly comprises:
an inner member having an outer engagement surface and a bore extending at least partway therethrough;
an outer member positioned at least partially around the inner member, the outer member having an inner engagement surface contoured to a shape complementary to the outer engagement surface of the inner member; and
a self-lubricating liner disposed between the inner engagement surface of the outer member and the outer engagement surface of the inner member.
17 . The linkage apparatus of claim 16 wherein the liner of the bearing assembly comprises a polytetrafluoroethylene (“PTFE”) bonded with a thermoset resin.
18 . The linkage apparatus of claim 16 wherein the liner of the bearing assembly comprises a perfluorooctanoic acid (“PFOA”) polytetrafluoroethylene (“PTFE”) bonded with a polyimide resin system.
19 . The linkage apparatus of claim 16 wherein the liner of the bearing assembly comprises a Teflon® liner containing no PFOA.
20 . The linkage apparatus of claim 16 wherein the liner of the bearing assembly comprises a Teflon® liner containing PFOA.
21 . A bearing assembly for use in a linkage apparatus, the bearing assembly comprising:
an inner member having an outer engagement surface and a bore extending at least partway therethrough;
an outer member positioned at least partially around the inner member, the outer member having an inner engagement surface contoured to a shape complementary to the outer engagement surface of the inner member; and
a self-lubricating liner disposed between the inner engagement surface of the outer member and the outer engagement surface of the inner member, the liner containing no PFOA.
22 . The linkage apparatus of claim 7 wherein the bearing assembly comprises:
an inner member having an outer engagement surface and a bore extending at least partway therethrough;
an outer member positioned at least partially around the inner member, the outer member having an inner engagement surface contoured to a shape complementary to the outer engagement surface of the inner member; and
a self-lubricating liner disposed between an inner surface of the bore of the inner member and a shaft extending at least partway therethrough.
23 . The linkage apparatus of claim 8 wherein the bearing assembly comprises:
an inner member having an outer engagement surface and a bore extending at least partway therethrough;
an outer member positioned at least partially around the inner member, the outer member having an inner engagement surface contoured to a shape complementary to the outer engagement surface of the inner member; and
a self-lubricating liner disposed between an inner surface of the bore of the inner member and a shaft extending at least partway therethrough.