Method and apparatus for positioning a workpiece for polishing

Claim 1

A METHOD OF ACCURATELY SECURING A WORKPIECE IN POSITION TO BE POLISHED ON A WORKHOLDER, SAID WORKPIECE HAVING AN ASPHERIC SURFACE OF REVOLUTION WHICH DEVIATES BY ONLY SMALL AMOUNTS FROM A BASIC SPHERICAL SURFACE, AND SAID WORKHOLDER BEING OF THE TYPE COMPRISING AN OUTER WORKHOLDER PART HAVING A SPHERICAL END SURFACE SUBSTANTIALLY CONFORMING TO SAID BASIC SPHERICAL SURFACE AND ENCIRCLING A CYLINDRICAL HOLE DIMENSIONED TO CLOSELY ENCIRCLE SAID WORKPIECE, THE AXIS OF SAID HOLE BEING COLLINEAR WITH A RADIUS OF SUCH SPHERICAL END SURFACE, AND AN AXIALLY MOVABLE INNER WORKHOLDER PART WHICH FITS CLOSELY INTO SAID HOLE, SAID METHOD COMPRISING THE STEPS OF RETRACTING THE INNER WORKHOLDER PART WITHIN THE OUTER WORKHOLDER PART, INSERTING THE WORKPIECE IN THE OUTER WORKHOLDER PART, SUPPORTING SAID WORKPIECE THEREIN ON THE INNER WORKHOLDER PART WITH ITS AXIS COLLINEAR WITH THE AXIS OF THE CYLINDRICAL HOLE AND ITS ASPHERIC SURFACE EXPOSED TOWARDS THE OPENING OF THE CYLINDRICAL HOLE, LOCATING A REMOVABLE STOP MEMBER HAVING A RIGID ABUTMENT SURFACE CURVED TO MATCH THE SPHERICAL END SURFACE ON THE OUTER WORKHOLDER PART IN A POSITION IN ENGAGEMENT WITH THE EDGE PORTION OF SAID SPHERICAL END SURFACE SURROUNDING SAID CYLINDRICAL HOLE IN WHICH A PORTION OF SAID ABUTMENT SURFACE SUBSTANTIALLY SMALLER THAN SAID ASPHERIC WORKPIECE SURFACE OVERLIES SAID HOLE, APPLYING AN ADJUSTING FORCE TO EFFECT AXIAL MOVEMENT OF THE INNER WORKHOLDER PART WITHIN THE OUTER WORKHOLDER PART TO BRING THE WORKPIECE INTO AN OPERATIVE POSITION WITH A SMALL PORTION OF ITS ASPHERIC SURFACE IN ENGAGEMENT WITH THE STOP MEMBER, SECURING THE WORKPIECE IN SUCH OPERATIVE POSITION AGAINST FURTHER MOVEMENT RELATIVE TO THE OUTER WORKHOLDER PART, AND REMOVING THE STOP MEMBER.

Claim 2

A METHOD OF ACCURATELY SECURING A WORKPIECE IN POSITION TO BE POLISHED ON A WORKHOLDER, SAID WORKPIECE HAVING AN ASPHERIC SURFACE OF REVOLUTION WHICH DEVIATES BY ONLY SMALL AMOUNTS FROM A BASIC SPHERICAL SURFACE, AND SAID WORKHOLDER BEING OF THE TYPE COMPRISING AN OUTER WORKHOLDER PART HAVING A SPHERICAL END SURFACE SUBSTANTIALLY CONFORMING TO SAID BASIC SPHERICAL SURFACE AND ENCIRCLING A CYLINDRICAL HOLE DIMENSIONED TO CLOSELY ENCIRCLE SAID WORKPIECE, THE AXIS OF SAID HOLE BEING COLLINEAR WITH A RADIUS OF SUCH SPHERICAL END SURFACE, AND AN AXIALLY MOVABLE INNER WORKHOLDER PART WHICH FITS CLOSELY INTO SAID HOLE, SAID METHOD COMPRISING THE STEPS OF RETRACTING THE INNER WORKHOLDER PART WITHIN THE OUTER WORKHOLDER PART, INSERTING THE WORKPIECE IN THE OUTER WORKHOLDER PART, SUPPORTING SAID WORKPIECE THEREIN ON THE INNER WORKHOLDER PART WITH ITS AXIS COLLINEAR WITH THE AXIS OF THE CYLINDRICAL HOLE AND ITS ASPHERIC SURFACE EXPOSED TOWARDS THE OPENING OF THE CYLINDRICAL HOLE, LOCATING A REMOVABLE STOP MEMBER HAVING A RIGID ABUTMENT SURFACE CURVED TO MATCH THE SPHERICAL END SURFACE ON THE OUTER WORKHOLDER PART IN A POSITION IN ENGAGEMENT WITH THE EDGE PORTION OF SAID SPHERICAL END SURFACE SURROUNDING SAID CYLINDRICAL HOLE IN WHICH A PORTION OF SAID ABUTMENT SURFACE SUBSTANTIALLY SMALLER THAN SAID ASPHERIC WORKPIECE SURFACE OVERLIES SAID HOLE, APPLYING AN ADJUSTING FORCE TO EFFECT AXIAL MOVEMENT OF THE INNER WORKHOLDER PART WITHIN THE OUTER WORKHOLDER PART TO BRING THE WORKPIECE INTO AN OPERATIVE POSITION WITH A SMALL PORTION OF ITS ASPHERIC SURFACE IN ENGAGEMENT WITH THE STOP MEMBER, SECURING THE WORKPIECE IN SUCH OPERATIVE POSITION AGAINST FURTHER MOVEMENT RELATIVE TO THE OUTER WORKHOLDER PART, AND REMOVING THE STOP MEMBER.