Medical three-dimensional locating apparatus

Claim 1

A medical three-dimensional locating apparatus, comprising: an arm means unit, comprising a first arm pivotally supported for turning about a first axis, said first arm means having a first end located at said first axis and extending in a direction perpendicular to said first axis to a second end, a second arm pivotally supported to said first arm means for turning about a second axis which is oriented to be perpendicular to said first axis, said second arm means having a first end rotatably supported to the second end of the first arm means and a length extending therefrom to a distal end located on the first axis, said second arm means comprising a rack section mounted at said distal end, and an operational unit mounted to the rack section to be disposed and movable coaxially with the first axis and toward and away from an intersection point of the first and second axes; support means for movably supporting the arm unit so that the arm unit can be controllably moved in vertical, longitudinal and lateral directions to locate the arm unit at a selected position; and a plurality of position detectors respectively mounted at selected locations on the first arm means, the second arm means, the operational unit and the support means for detecting respective positions thereof, for thereby providing signals enabling determination of both a position of said intersection point and a position of a tip of the operational unit relative to said intersection point, so that the second arm means can be moved in response to said detected positions to move said operational unit along a spherical surface about said intersection point so that said tip of the operational unit is always disposed to indicate said intersection point.