Actuator limiters for multiple disk-stack, shared actuator hard disk drive

1. A multiple disk-stack, shared actuator hard disk drive comprising:

an enclosure base;

a first disk media stack rotatably mounted on a first spindle;

a second disk media stack rotatably mounted on a second spindle;

a head slider comprising a read/write head configured to read from and to write to a disk medium;

an actuator comb configured to move said head slider to access portions of at least one disk medium of said first disk media stack and at least one disk medium of said second disk media stack, said actuator comb comprising:

an armature housing a voice coil and comprising a left arm, a right arm, and a back arm interconnecting said left arm and said right arm,

a cam-lock feature; and

an actuator limiter comprising:

a rotatable cam-roller that engages with said cam-lock feature and thereby temporarily holds in place said actuator comb.

2. The hard disk drive of claim 1 , wherein said actuator limiter further comprises:

a leaf spring structure to which said cam-roller is rotatably coupled, wherein said leaf spring structure holds said cam-roller in contact with said armature of said actuator comb;

wherein rotation of said actuator comb causes rotation of said cam-roller.

3. The hard disk drive of claim 2 , wherein said leaf spring structure is affixed to said base.

4. The hard disk drive of claim 2 , further comprising:

a voice coil motor (VCM) magnet housing plate;

wherein said leaf spring structure is affixed to said magnet housing plate.

5. The hard disk drive of claim 1 , wherein said cam-lock feature comprises a divot in a back surface of said back arm of said armature.

6. The hard disk drive of claim 5 , wherein said cam roller is positioned outside of an area enclosed by said armature.

7. The hard disk drive of claim 1 , wherein said cam-lock feature comprises a divot in said voice coil.

8. The hard disk drive of claim 7 , wherein said cam roller is positioned inside of an area enclosed by said armature.

9. The hard disk drive of claim 7 , wherein said cam roller is positioned outside of an area enclosed by said armature.

10. The hard disk drive of claim 1 , further comprising:

a load/unload ramp coupled with said base;

wherein said cam-lock feature is positioned at or near a midway location of said back arm of said armature, and wherein said actuator comb held in place by said cam-roller corresponds to said head slider being positioned on said ramp.

11. A method for controlling rotational travel of an actuator comb housing a head slider in a multiple disk-stack, shared actuator hard disk drive, the method comprising:

driving said actuator comb to rotate, thereby causing a rotatable cam-roller, forced into contact with said actuator comb by a leaf spring structure to which said cam-roller is affixed, to rotate, such that said cam-roller engages with a cam-lock feature of said actuator comb, thereby temporarily holding in place said actuator comb.

12. The method of claim 11 , wherein said holding in place is in response to reducing a drive signal, to said actuator, corresponding to said driving.

13. The method of claim 11 , wherein said holding in place is in response to substantially ending a drive signal, to said actuator, corresponding to said driving.

14. The method of claim 11 , wherein said actuator comb held in place by engagement of said cam-roller with said cam-lock feature corresponds to said head slider being positioned on a load/unload ramp positioned between a first disk stack and an adjacent second disk stack.

15. The method of claim 11 , further comprising:

driving said actuator comb to forcibly disengage said cam-roller from said cam-lock feature, thereby moving said head slider to a position over a disk from a first disk stack or a disk from an adjacent second disk stack.