Patent ID: 8029371

Claim:
A torque coupling for a rotor head of a rotary-wing aircraft, the torque coupling being configured for rotation with a mast and for causing rotation of an attached yoke; the coupling comprising: a plurality of pairs of trunnions adapted for rotation with the mast about an axis of rotation, each trunnion in a single pair forming a flapping axis by being located opposingly such that the flapping axis is located through a center axis of each of the trunnions within the single pair, the trunnions extending generally radially relative to the axis of rotation; a plurality of pad-bearing assemblies, each assembly comprising: a central member pivotally coupled to each trunnion; a laminated spherical bearing located in each central member; a plurality of laminated pad bearings affixed to opposing sides of the central member, each pad bearing comprising a plurality of rigid layers and a plurality of elastomeric layers in a stacked configuration, at least one elastomeric layer being located between adjacent rigid layers, wherein each pad bearing is curved such that a focus of the curvature of each pad bearing lies on the corresponding flapping axis located through the corresponding central member so as to at least partly orient any spherical cocking of each spherical bearing to be concentric with each corresponding trunnion; and a bearing mount affixed to at least one pad bearing and adapted to be connected to a yoke; wherein the pad-bearings allow for relative motion between each central member and the associated bearing mounts through elastic shear deformation of the elastomeric layers of the pad bearings, which allows for relative motion between an attached yoke and the mast.