US Patent 10302140 Spline alignment

A gas turbine shaft assembly comprises first and second axially mating shafts. The first shaft has a circumferential array of splines configured to mesh with a corresponding circumferential array of splines on the second shaft. The first shaft defines at least one axially extending slot aligned with one of the splines on the first shaft. The second shaft has at least one radial projection aligned with one of the splines on the second shaft. The engagement of the radial projection with the slot provides angular correspondence between the splines of the first and the second shafts prior to axial engagement of the splines.