US Patent 10556690 Armrest assembly for aircraft seating

An armrest assembly comprising a base structure and an upper structure that has an upper surface providing an armrest. The upper structure is movable with respect to the base structure between an upper position and a lower position under the control of a lockable actuator that is operable to lock the upper structure with respect to the base structure in any one of a plurality of adoptable positions. A second locking device is operable to lock the upper structure with respect to the base structure in at least one of the adoptable positions, the locking device including locking elements that inter-engage mechanically when the second locking device locks the upper structure with respect to said base structure.