Centering apparatus and method

A centering apparatus for centering a disk including a central opening, the apparatus comprising a plurality of pairs of actuator units and a center member disposed within the central opening of the disk;

• the actuator units of each of the pairs facing each other through the disk,
• each of the pairs of actuator units including a member which moves linearly and can come into contact with the disk;
• the plurality of pairs of actuator units include a first pair of actuator units which face each other via the disk and respectively include first and second rods which move linearly in a first direction, and a second pair of actuator units which face each other via the disk and respectively include third and forth rods which move linearly in a second direction, wherein the second direction is not parallel to the first direction;
• the first and second pairs of actuator units act to center the disk at a centered position defined relative to actuator positions (x1+x2)/2, (y1+y2)/2), where:
• x1 is a position of the second rod which contacts an outer perimeter of the disk in a state in which the first rod contacts the outer perimeter of the disk and an inner edge thereof contacts the center member;
• x2 is a position of the second rod which contacts the outer perimeter in a state in which the inner edge contacts the center member in a position different from that in which the inner edge contacts the center member when the position of the second rod is said x1;
• y1 is a position of the fourth rod which contacts the outer perimeter of the disk in a state in which the third rod contacts the outer perimeter of the disk and the inner edge contacts the center member;
• and
• y2 is a position of the fourth rod which contacts the outer perimeter in a state in which the inner edge contacts the center member in a position different from that in which the inner edge contacts the center member when the position of the fourth rod is said y1;
• whereby
• the first and second pairs of actuator units are drivable to center the disk at the centered position by driving the second rod to the actuator position (x1+x2)/2 while driving the fourth rod to the actuator position (y1+y2)/2), and/or by driving the first rod to the actuator position (x1+x2)/2 less an outer diameter of the disk while driving the third rod to the actuator position (y1+y2)/2 less the outer diameter of the disk.

A centering method for centering a disk about a center member, comprising the steps of:

• driving a plurality of pairs of actuator units, the actuator units of each of the pairs facing each other through the disk, each of the actuator units including a member which moves linearly and can come into contact with the disk;
• centering the disk by the plurality of pairs of actuator units;
• providing first and second pairs of actuator units to center the disk at a centered position,
• wherein the first pair of actuator units face each other via the disk and respectively include first and second rods which move linearly in a first direction, and the second pair of actuator units which face each other via the disk and respectively include third and fourth rods which move linearly in a second direction, wherein the second direction is not parallel to the first direction;
• and
• driving the first and second pairs of actuator units to center the disk at the centered position by driving at least one of the actuator units of each of the pairs to respective positions (x1+x2)/2, (y1+y2)/2), the centered position being defined relative to the respective positions (x1+x2)/2, (y1+y2)/2);
• where:
• x1 is a position of the second rod which contacts the outer perimeter of the disk in a state in which the first rod contacts the outer perimeter of the disk and an inner edge thereof contacts the center member;
• x2 is a position of the second rod which contacts the outer perimeter in a state in which the inner edge contacts the center member in a position different from that in which the inner edge contacts the center member when the position of the second rod is said x1;
• y1 is a position of the fourth rod which contacts the outer perimeter of the disk in a state in which the third rod contacts the outer perimeter of the disk and the inner edge contacts the center member;
• and
• y2 is a position of the fourth rod which contacts the outer perimeter in a state in which the inner edge contacts the center member.