Patent ID: 7458881

Claim:
An apparatus for treating an internal surface of a hollow casting, the apparatus comprising: at least two fixing means, each for fixing a hollow casting, such that a surface of such hollow casting faces a predetermined direction; and oscillating means for oscillating said fixing means, said oscillating means comprising: a prime mover; a rotation shaft connected to said prime mover; at least two cranks connected to said rotation shaft, each crank for changing a rotational motion of said rotation shaft into a reciprocating motion in a predetermined direction, thereby oscillating such hollow casting; oscillating plates, each connected to a respective crank via a rod and to a respective fixing means, said oscillating plates being substantially symmetrically positioned relative to said prime mover; wherein each of said oscillating plates comprises a slide guide for causing said oscillating plate to move in a rectilinear motion; and said oscillating plates are for oscillating at a predetermined frequency, such that each fixing means oscillates in an opposite direction from the other fixing means.