Patent ID: 8210822

Claim:
A dovetail for a steam turbine, comprising a rotating blade curved axial entry dovetail having a four hook profile and a rotor wheel dovetail slot sized to receive the blade dovetail, the blade dovetail and wheel dovetail slot each comprising a plurality of slanted crush surfaces, a plurality of non-contact surfaces, and a plurality of necks that each provide a transition between a slanted crush surface and a non-contact surface, wherein each neck comprises a slant angle defined by the transition of the slanted crush surface to the non-contact surface, wherein the slant angle ranges from about 62 degrees to about 90 degrees, the blade dovetail and wheel dovetail slot each further comprising: a plurality of hooks defined by a transition between a slanted crush surface to a non-contact surface, wherein each hook projects outward from a neck, the plurality of hooks of the blade dovetail and wheel dovetail slot each comprising a top hook, a first middle hook, a second middle hook and a bottom hook, the top hook and the first and second middle hooks of the blade dovetail are formed with two radii and a flat surface extending therebetween, wherein the two radii for the top hook are identical with each other, the two radii for the first middle hook are identical with each other and the two radii for the second middle hook are identical with each other, and wherein the radii of the top hook, first middle hook and second middle hook are all identical with each other.