Patent ID: 6560888
Filing Date: 2003-05-13
Classification: G01B

Abstract:
An internal shim having a dimension less than a dimension of a space defined by boundaries to be accurately measured, said internal shim comprising:a chassis having a first side and a second side defining a plurality of push rod passages and a plurality of pairs of gripper openings wherein said plurality of pairs of gripper openings are separated by said plurality of push rod passages; a shim top end wider than said dimension to be measured having a top and bottom and defining a plurality of push rod openings therethrough, said bottom of the shim top end being attached to one end of said chassis such that said plurality of push rod openings of said shim top end and said plurality of push rod passages of said chassis are aligned; A plurality of guide openings within said shim top end, wherein said plurality of guide openings are in alignment with a plurality of guide channels, wherein said plurality of guide openings and said plurality of guide channels are disposed on said first and second sides of chassis; a plurality of push rods having top ends and bottom ends disposed within said plurality of push rod passages and passing through said plurality of push rod openings, said plurality of push rods having lengths substantially equal to the lengths of said plurality of push rod passages and having cross sectional dimensions that are uniform along most of their lengths and having a plurality of sections corresponding to the plurality of pairs of gripper openings wherein said cross sectional dimensions of said sections taper from larger dimensions to smaller uniform cross sectional dimensions of said plurality of push rods; a plurality of pairs of gripper elements, having grippers and rods attached thereto, wherein said plurality of pairs of gripper elements have top ends rotatably attached to said chassis and said plurality of pairs of gripper openings and said plurality of pairs of gripper elements are aligned to be adjacent to said plurality of sections wherein said plurality of sections have cross sectional dimensions that taper from larger dimensions to smaller uniform dimensions; a plurality of arms, having first ends and second ends, wherein said first ends are rotatably attached to said top of the shim top end, said plurality of arms passing over said plurality of push rod openings and co-acting with said top end of the push rods and said second ends of the arms being adjustably attached to said top of the shim top end; and a plurality of spring mechanisms disposed between said sections of said push rods having a tapered cross section and said chassis.