Refractor with a synchronized cylinder lens axis and cross cylinder lens axis

Claim 1

In combination with vision analysis apparatus having a battery, including: a viewing tube; a cylinder lens assembly having cylinder lenses mounted thereon with each cylinder lens having a cylinder axis; means for positioning a selected cylinder lens in alignment with said viewing tube; means for setting the cylinder axis of the selected cylinder lens in the viewing tube; and a cross cylinder assembly mounted on the battery and having a cross cylinder lens, a yoke lying on a flip axis for holding the cross cylinder lens, a turret movably carrying the cross cylinder lens between a first position aligned with the selected cylinder lens and said viewing tube and another position unaligned with the selected cylinder lens and said viewing tube, and means for rotating the yoke in flipping movement about the flip axis; the improvement comprising, crank assembly means for synchronous alignment of the flip axis with the cylinder axis of the selected cylinder lens when the turret is in the first position, including at least two crank mechanisms, each crank mechanism lying on a plane parallel to the plane of the other crank mechanism, each crank mechanism having a first and second crank in spaced relation to each other, the first crank of one crank mechanism eccentrically connected by a connection means to the first crank of the other crank mechanism, the connection means lying on a plane at an angle to the planes on which the crank mechanisms lie.