Patent ID: 8851852

Claim:
A turbine assembly comprising: a rotor having a rotational axis, an outer surface, and a channel formed in the outer surface and which circumscribes the rotor; wherein the channel includes an axially extending channel foot with a base and a radially inward facing land, a radial distance between the base and the land defining a foot radial height, and a neck portion extending radially between the foot and the outer surface, the neck portion having a first and a second axial end wall, at least one of the first and second axial end walls having a taper angle which, in a radial outward direction, narrows the neck portion; a row of rotationally fittable blades circumferentially distributed in the channel around the rotor, each blade comprising a root at least partially located in the channel, the root including an axially extending root foot with a base and a radial height extending from the base, a neck extending radially from the root foot having a first and a second axial end wall, each end wall tapered to complement the taper angle of the end walls of the channel neck portion, and a platform on a radial distal end of the root; wherein the blades each have a parallelogram shaped platform, root, or both, the blades being rotationally fittable in the channel; wherein the root radial height is less than the channel foot radial height; wherein differences in radial height between the root and channel foot, the taper, and platform shape, root shape, or both, in combination allowing over-rotation of the root when the base of the root is in contact with the channel base as compared to when the root foot is in contact with the channel land to an extent that enables fitting of a last blade in the channel; and wherein the complementary taper of the neck axial end walls and the channel neck end walls prevents rotation in the channel when the root foot is in contact with the channel land.