Patent ID: 7063479

Claim:
A link mechanism for a surgical assist robot to determine a position and direction of an axial rod, comprising: an axial rod; and two spherical bearings to support said axial rod, said two spherical bearings being capable of changing positions, wherein a motion of one of said two spherical bearings relative to said axial rod along an axis of said axial rod is constrained, and the other of said spherical bearings can travel along said rod; and wherein said rod and each of said spherical bearings constructed of material drawn from a class of paramagnetic materials of small magnetic susceptibility including ceramic material, glass fiber-reinforced material, carbon fiber reinforced material, wood, and non-ferrous metal, said material permitting use of the robot for magnetic resonance and therapy applications in an environment of an electromagnetic field without generation of artifacts in images produced by magnetic resonance and therapy applications.