Patent ID: 7604460

Claim:
A rotorcraft rotor comprising: a hub, a first blade having a first twistable structure secured to the hub by a first bolt/nut combination and a first annular bushing, said first annular bushing being slidable on said first bolt, a second blade having a second twistable structure secured to the hub by a second bolt/nut combination and a second annular bushing, said second annular bushing being slidable on said second bolt, each twistable structure comprising a plurality of stacked metal strips, said first and second blades being adjacent, wherein: the first twistable structure is secured to the hub by the first bolt, by a washer serving to transmit clamping force to the first annular bushing, the washer bearing against the first annular bushing and being separate and distinct therefrom, and by the first annular bushing transmitting clamping force to the first twistable structure; the second twistable structure is secured to the hub by the second bolt, by said washer serving to transmit clamping force to the second annular bushing, the washer bearing against the second annular bushing and being separate and distinct therefrom, and by the second annular bushing transmitting clamping force to the second twistable structure; and said washer being formed by a thin plate which has a form of a circular arc and is pierced by two orifices spaced apart by a distance corresponding to the spacing between the axes of the first and second bolts; whereby the nuts of the first and second bolts form abutments preventing the washer from turning relative to the hub or relative to the corresponding twistable structure, each of said nuts having sides and a planar bottom surface, said planar bottom surface being in direct contact with said washer and being delimited by said sides.