Patent ID: 8864406

Claim:
An apparatus, comprising: first and second coaxial shafts, the first and second shafts extending along, and being rotatable about, a central axis, the first and second shafts being coupled together by a splined major coupling at a coupling region of the apparatus, the major coupling enabling the shafts to co-rotate about the central axis, a torque element connected to the first and second shafts via two splined minor couplings, the torque element being operable to force the first and second shafts to relatively rotate about the central axis in order to apply a predetermined preload to the major coupling, and each shaft having opposing abutment features, the opposing abutment features having axial surfaces that abut one another, thereby defining a predetermined axial position between the shafts at which the predetermined preload is applied, wherein the splined major coupling comprises a helical angle about the shafts, and wherein the two splined minor couplings are angled relative to one another, the angle between the two splined minor couplings being less than the helical angle of the major coupling.