Patent ID: 11873092
Assignee: THE BOEING COMPANY
Field: Transport (Mechanical engineering)
Classification: CPC B  F | IPC B  F

Claim 8:
9. The trim actuator according to claim 1, further comprising
a housing that contains the flange and the anti-back-drive mechanism,
wherein:
the flange comprises a flange first surface and a flange second surface, opposite the flange first surface;
the anti-back-drive mechanism comprises:
a first ratchet gear, concentrically mounted on the power screw so that the power screw is rotatable relative to the first ratchet gear, wherein the first ratchet gear comprises a first-ratchet-gear first surface, facing the flange first surface, and a first-ratchet-gear second surface, opposite the first-ratchet-gear first surface and facing the housing;
a first ratchet pawl that prevents the first ratchet gear from rotating in the first rotational direction when the first ratchet pawl engages the first ratchet gear;
a first friction device, located between the flange first surface and the first-ratchet-gear first surface; and
a first thrust bearing, located between the first-ratchet-gear second surface and the housing;

the first friction device is configured to form a frictional coupling between the flange and the first ratchet gear when the first force is applied to the nut in the first axial direction along the power screw, wherein the frictional coupling between the flange and the first ratchet gear opposes relative rotational motion between the flange and the first ratchet gear; and
the internal loading of the anti-back-drive mechanism, measured by the sensor when the first force is applied to the nut in the first axial direction along the power screw, is a first load, applied to the first ratchet pawl by the first ratchet gear.