Disk drive with translatable ramp

1. A disk drive comprising:

a disk drive base;

a disk rotably coupled to the disk drive base, the disk defining a disk axis of rotation and having an outer circumference;

an actuator coupled to the disk drive base, the actuator defining an actuator pivot axis;

a head gimbal assembly that includes a proximate end that is attached to the actuator, and a distal end, the distal end including a lift tab;

a ramp, the ramp including a lift tab supporting surface located as close to the actuator pivot axis as is the lift tab, a portion of the lift tab supporting surface extending over the outer circumference of the disk with the ramp in a normal operating position, the ramp also including a ramp guiding surface, the ramp guiding surface being in contact with a mating surface of the disk drive base; and

a fastener configured to selectively allow or prevent relative translation between the ramp and the disk drive base;

wherein said contact between the ramp guiding surface and the mating surface constrains the relative translation so that the relative translation changes the distance between the lift tab supporting surface and the disk axis of rotation more than the relative translation changes the distance between the lift tab supporting surface and the actuator pivot axis; and

wherein the relative translation is oriented and of sufficient extent to allow the ramp to translate from the normal operating position away from the disk axis of rotation to a second position where the entire ramp is outside the disk outer circumference, while keeping the lift tab supporting surface close enough to the actuator pivot axis to remain within reach of the lift tab.

2. The disk drive of claim 1 wherein the smallest angle between the relative translation and a line drawn from the lift tab supporting surface to the disk axis of rotation is smaller than the smallest angle between the relative translation and a line drawn from the lift tab supporting surface to the actuator pivot axis.

3. The disk drive of claim 1 wherein the ramp guiding surface is an outer surface of a pin protruding from the ramp, and the mating surface is an inner surface of a groove in the disk drive base.

4. The disk drive of claim 1 wherein the ramp guiding surface is an inner surface of a groove in the ramp, and the mating surface is the outer surface of a pin protruding from the disk drive base.

5. The disk drive of claim 1 wherein the fastener is a screw passing through a slot in the ramp into a threaded hole in the disk drive base.

6. The disk drive of claim 1 wherein the fastener is a snap-fit frictional interface between an inner surface of a slot in the ramp and an outer surface of a pin protruding from the disk drive base.

7. The disk drive of claim 6 wherein the ramp guiding surface is a flat outer surface of the ramp that lies in a plane that is parallel to the actuator pivot axis, and the mating surface is a flat inner surface of the disk drive base that lies in an adjacent plane that is also parallel to the actuator pivot axis.

8. The disk drive of claim 1 wherein the relative translation can change the distance between the lift tab supporting surface and the disk axis of rotation by as much as 1 mm but no more than 6 mm.

9. The disk drive of claim 1 wherein the ramp further includes a recession for temporary receipt of a relative translation inducing tool, the relative translation inducing tool not being a part of the disk drive.

10. The disk drive of claim 9 wherein the recession comprises a tooling hole.

11. The disk drive of claim 1 wherein the ramp comprises an opaque material.

12. A disk drive comprising:

a disk drive base;

a disk rotably coupled to the disk drive base, the disk defining a disk axis of rotation and having an outer circumference;

an actuator coupled to the disk drive base, the actuator defining an actuator pivot axis;

a head gimbal assembly that includes a proximate end that is attached to the actuator, and a distal end, the distal end including a lift tab;

a ramp, the ramp including a lift tab supporting surface located as close to the actuator pivot axis as is the lift tab, the ramp also including a ramp guiding surface, the ramp guiding surface being in contact with a mating surface of the disk drive base; and

a fastener configured to selectively allow or prevent relative translation between the ramp and the disk drive base;

wherein said contact between the ramp guiding surface and the mating surface constrains the relative translation so that the relative translation changes the distance between the lift tab supporting surface and the disk axis of rotation more than the relative translation changes the distance between the lift tab supporting surface and the actuator pivot axis; and

wherein the ramp comprises first material at the lift tab supporting surface and the ramp comprises a second material of relatively higher compressive strength adjacent the fastener.

13. The disk drive of claim 12 wherein the first material has a compressive strength less than 100 MPa, and the second material has a compressive strength greater than 100 MPa.

14. The disk drive of claim 13 wherein the first material includes acetyl homopolymer and the second material includes polyetherimide.

15. A disk drive comprising:

a disk drive base;

a disk rotably coupled to the disk drive base, the disk defining a disk axis of rotation and having an outer circumference;

an actuator coupled to the disk drive base, the actuator defining an actuator pivot axis;

a head gimbal assembly that includes a proximate end that is attached to the actuator, and a distal end, the distal end including a lift tab;

a ramp, the ramp including a lift tab supporting surface located as close to the actuator pivot axis as is the lift tab, the ramp also including a ramp guiding surface, the ramp guiding surface being in contact with a mating surface of the disk drive base; and

a fastener configured to selectively allow or prevent relative translation between the ramp and the disk drive base;

wherein said contact between the ramp guiding surface and the mating surface constrains the relative translation so that the relative translation changes the distance between the lift tab supporting surface and the disk axis of rotation more than the relative translation changes the distance between the lift tab supporting surface and the actuator pivot axis; and

wherein the relative translation is oriented and of sufficient extent to allow the lift tab supporting surface to translate away from the disk axis of rotation to a position outside the disk outer circumference, while keeping the lift tab supporting surface close enough to the actuator pivot axis to remain within reach of the lift tab,

wherein the ramp further includes a recession for temporary receipt of a relative translation inducing tool, the relative translation inducing tool not being a part of the disk drive, and

wherein the recession comprises two opposing V-shaped notches.

16. A disk drive comprising:

a disk drive base;

a disk rotably coupled to the disk drive base, the disk defining a disk axis of rotation and having an outer circumference;

an actuator coupled to the disk drive base, the actuator defining an actuator pivot axis;

a head gimbal assembly that includes a proximate end that is attached to the actuator, and a distal end, the distal end including a lift tab;

a ramp, the ramp including a lift tab supporting surface located as close to the actuator pivot axis as is the lift tab, a portion of the lift tab supporting surface extending over the outer circumference of the disk with the ramp in a normal operating position, the ramp also including a ramp guiding surface, the ramp guiding surface being in contact with a mating surface of the disk drive base; and

a fastener configured to selectively allow or prevent relative translation between the ramp and the disk drive base;

wherein said contact between the ramp guiding surface and the mating surface constrains the relative translation so that the relative translation changes the distance between the lift tab supporting surface and the disk axis of rotation more than the relative translation changes the distance between the lift tab supporting surface and the actuator pivot axis; and

wherein the relative translation is oriented and of sufficient extent to eliminate any overlap of the ramp over the disk outer circumference.