Patent ID: 7556083

Claim:
A plugged assembly of cores for forming a blade including a central longitudinal cavity and a plurality of outer longitudinal cavities positioned adjacent to the central longitudinal cavity, comprising: a first core of a ceramic material having a body configured to form the central longitudinal cavity and having a first end portion including a mortise; and a second core of said ceramic material having a body configured to form the plurality of outer longitudinal cavities and having a second end portion including a tenon to form a mortise and tenon type connection with the first core, wherein the first end portion of the first core is connected to the second end portion of the second core by the mortise and tenon type connection to form residual spaces joining a first end of the central longitudinal cavity and first ends of the plurality of outer longitudinal cavities, wherein the first core and the second core are only connected at the mortise and tenon type connection such that the central longitudinal cavity and the plurality of outer longitudinal cavities are only directly connected at the residual spaces, said residual spaces formed by the mortise and tenon type connection in the assembly of the two cores contain a material other than said ceramic material and are configured to reduce the possibility of flashings, and said material is positioned within said residual spaces such that said residual spaces are free of metal after said metal is poured over said assembly.