Patent ID: 6170367
Filing Date: 2001-01-09
Classification: B23B,B24B,Y10T

Abstract:
A contact lens forming machine, comprising:a spindle that holds a lens blank in an X-Y plane and rotates it around a spindle axis that is oriented along a Z-axis;a cutting tool that is held perpendicular to the lens blank;a slide mechanism that moves the spindle and cutting tool relative to each other in the X and Z directions to form a base curve on the lens blank;a single-point hinge on said slide mechanism which forms a pivot point, said hinge having a lever arm that is pinned at one end and is unpinned at the other end and a tool arm that extends from the lever arm to hold the cutting tool perpendicular to the rotating lens blank, said hinge bending in the X-Z plane and being rigid along its Y-axis; andan actuator that applies force to the unpinned end of the lever arm causing it to move back-and-forth through a stroke range, said motion being translated through said hinge to said tool arm so that the cutting tool oscillates back-and-forth through a shallow arc in the Z direction in synchronism with the lens blank rotation thereby superimposing a toric deviation on the base curve,said hinge's lever and tool arms being ratioed so that a) the force applied to the lever arm is amplified to the cutting tool to resist the force of the rotating lens pushing back on the tool and b) the stroke range of the lever arm is reduced to reduce any side-to-side motion of the cutting tool as it oscillates through the shallow arc.