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An aircraft tail rotor system is provided and includes a rotating element, a translating element and a structure including a first bearing in series with a second bearing, the first bearing including a component rotatable with and movable within the rotating element in accordance with translational

An aircraft tail rotor system is provided and includes a rotating element, a translating element and a structure including a first bearing in series with a second bearing, the first bearing including a component rotatable with and movable within the rotating element in accordance with translational movement of the translating element. The structure is configured to selectively use the second bearing to prevent transmission of rotational energy from the rotating element to the translating element in an event of a seizing of the first bearing.

대표청구항 ▼

1. An aircraft tail rotor system, comprising: a tail rotor shaft;a pitch change servo rod;a bearing assembly including a first bearing arranged in series relative to and spaced from a second bearing, the first bearing including a first raceway, a second raceway, and a plurality of bearing arranged t

1. An aircraft tail rotor system, comprising: a tail rotor shaft;a pitch change servo rod;a bearing assembly including a first bearing arranged in series relative to and spaced from a second bearing, the first bearing including a first raceway, a second raceway, and a plurality of bearing arranged therebetween, the first raceway being rotatable with and movable within the tail rotor shaft in accordance with translational movement of the pitch change servo rod, the second bearing including an third raceway, a fourth raceway and a plurality of bearings arranged therebetween;a connection non-rotatably coupling the third raceway of the second bearing and the first raceway of the first bearing; anda lock coupled to the second bearing, the lock selectively preventing rotation of the third raceway relative to the fourth raceway, the lock being configured to directly and independently respond to a seizing of the first bearing at the second bearing from a transmission of rotation of the first bearing to the second bearing and to selectively use the second bearing to prevent transmission of rotational energy from the tail rotor shaft to the pitch change servo rod in an event of the seizing of the first bearing. 2. The aircraft tail rotor system according to claim 1, wherein the lock is disposed in an operator accessible location. 3. The aircraft tail rotor system according to claim 1, wherein the lock comprises a frangible element that is breakable in the event of the seizing to selectively use the second bearing and which is not breakable when the first bearing is not seized, the frangible element comprising: a first frangible body, which includes a breakable member and which is affixed to the pitch change servo rod; anda second body, which includes a boss disposed to mechanically interfere with the breakable member and which is affixed to a component of the second bearing. 4. The aircraft tail rotor system according to claim 1, wherein the lock comprises: a star washer including a hub affixed to the pitch change servo rod and radial vanes emanating radially from the hub;a star washer receiver body affixed to a component of the second bearing and including a body having radial vane depressions; andan elastic element disposed to urge the radial vanes into the radial vane depressions. 5. A bearing assembly, comprising: a primary bearing including first and second raceways, the first raceway being rotatable with and movable within a tail rotor shaft in accordance with movements of a pitch change servo rod;a secondary bearing including a third raceway non-rotatably coupled to the second raceway and a fourth raceway non-rotatably coupled to the pitch change servo rod, the secondary bearing being arranged in series relative to and spaced from the primary bearing; anda lock coupled to the secondary bearing and disposed to prevent relative rotation between the third and fourth raceways and to selectively permit the relative rotation in accordance with a condition of the primary bearing being rotationally transmitted to the secondary bearing and directly independently responded to by the lock at the secondary bearing. 6. The bearing assembly according to claim 5, wherein the first and third raceways are outer raceways of the primary and secondary bearings, respectively, and the second and fourth raceways are inner raceways of the primary and secondary bearings, respectively. 7. The bearing assembly according to claim 5, wherein the lock is disposed in an operator accessible location. 8. The bearing assembly according to claim 5, wherein the lock is disposed to prevent the relative rotation in accordance with the primary bearing being un-seized and permits the relative rotation in accordance with the primary bearing being seized. 9. The bearing assembly according to claim 8, wherein the lock comprises a frangible element, which is breakable in accordance with the primary bearing being seized, and which is not breakable when the primary bearing is not seized, the frangible element comprising: a first frangible body, which includes a breakable member and which is affixed to the pitch change servo rod; anda second body, which includes a boss disposed to mechanically interfere with the breakable member and which is affixed to the third raceway of the second bearing. 10. The bearing assembly according to claim 8, wherein the lock comprises: a star washer receiver; anda star washer, which is rotatable relative to the star washer receiver in accordance with the primary bearing being seized, and which is not rotatable when the primary bearing is not seized, wherein: the star washer includes a hub affixed to the pitch change servo rod and radial vanes emanating radially from the hub,the star washer receiver is affixed to the third raceway of the second bearing and includes a body having radial vane depressions, andthe lock further comprises an elastic element disposed to urge the radial vanes into the radial vane depressions. 11. An aircraft tail rotor system, comprising: a tail rotor shaft;a pitch change servo rod; anda bearing assembly, comprising: a primary bearing including first and second raceways, the first raceway being rotatable with and movable within the tail rotor shaft in accordance with movements of the pitch change servo rod;a secondary bearing including a third raceway non-rotatably coupled to the second raceway and a fourth raceway non-rotatably coupled to the pitch change servo rod; anda lock coupled to the secondary bearing and disposed to be locked to prevent relative rotation between the third and fourth raceways and to be selectively unlocked to permit the relative rotation in accordance with a condition of the primary bearing being rotationally transmitted from the second raceway of the primary bearing to the third raceway of the secondary bearing and directly, independently, responded to by the lock at the secondary bearing. 12. The aircraft tail rotor system according to claim 11, further comprising a clevis to couple the fourth raceway and the pitch change servo rod. 13. The aircraft tail rotor system according to claim 11, wherein the first and third raceways are outer raceways of the primary and secondary bearings, respectively, and the second and fourth raceways are inner raceways of the primary and secondary bearings, respectively. 14. The aircraft tail rotor system according to claim 11, wherein the lock is disposed in an operator accessible location. 15. The aircraft tail rotor system according to claim 11, wherein the lock is disposed to prevent the relative rotation in accordance with the primary bearing being un-seized and permits the relative rotation in accordance with the primary bearing being seized. 16. The aircraft tail rotor system according to claim 15, wherein the lock comprises a frangible element, which is breakable in accordance with the primary bearing being seized, and which is not breakable with the primary bearing not seized, the frangible element comprising: a first frangible body, which includes a breakable member and which is affixed to the pitch change servo rod; anda second body, which includes a boss disposed to mechanically interfere with the breakable member and which is affixed to the third raceway of the second bearing. 17. The aircraft tail rotor system according to claim 15, wherein the lock comprises: a star washer receiver; anda star washer, which is rotatable relative to the star washer receiver in accordance with the primary bearing being seized, and which is not rotatable when the primary bearing is not seized, wherein: the star washer includes a hub affixed to the pitch change servo rod and radial vanes emanating radially from the hub,the star washer receiver is affixed to the third raceway of the second bearing and includes a body having radial vane depressions, andthe lock further comprises an elastic element disposed to urge the radial vanes into the radial vane depressions.