Disk drive with multiple actuators on a pivot axis

Abstract

A data storage device includes a stack of data storage disks mounted on a spindle, a first arm and a second arm. The stack comprises a first plurality of upper disks and second plurality of lower disks. The first arm is movably attached to an actuator shaft, the first arm having a first head end that supports a first head, the first arm configured to move along a first portion of the actuator shaft to enable the first head to interact with data storage surfaces of the first plurality of upper disks. The second arm has a second head end that supports a second head, the second arm attached to and configured to move along a second portion of the actuator shaft, independently of the first arm, to enable the second head to interact with data storage surfaces of the second plurality of lower disks.

What is claimed is: 
     
         1 . A data storage device comprising:
 a stack of data storage disks mounted on a spindle, the stack comprising a first plurality of upper disks and second plurality of lower disks;   a first arm movably attached to an actuator shaft, the first arm having a first head end that supports a first head, the first arm configured to move in a z direction along a first portion of the actuator shaft to enable the first head to interact with data storage surfaces of the first plurality of upper disks;   a plurality of locks spaced apart in the z direction and configured to retain the first arm in a selected one of a corresponding plurality of positions relative to the first portion of the actuator shaft; and   a second arm movably attached to the actuator shaft, the second arm having a second head end that supports a second head, the second arm configured to move along a second portion of the actuator shaft, independently of the first arm, to enable the second head to interact with data storage surfaces of the second plurality of lower disks.   
     
     
         2 . The data storage device of  claim 1 , wherein each of the first portion of the actuator shaft and the second portion of the actuator shaft is parallel to the spindle. 
     
     
         3 . The data storage device of  claim 1  comprising a first linear shaft motor configured to move the first arm along the first portion of the actuator shaft. 
     
     
         4 . The data storage device of  claim 3  comprising a second linear shaft motor configured to move the second arm along the second portion of the actuator shaft. 
     
     
         5 . The data storage device of  claim 1  comprising a pivot bearing between the first arm and the first portion of the actuator shaft. 
     
     
         6 . The data storage device of  claim 1  comprising two plates disposed at opposite ends of the first portion of the actuator shaft. 
     
     
         7 . The data storage device of  claim 1  comprising a holder connected to the first portion of the actuator shaft. 
     
     
         8 . The data storage device of  claim 7 , wherein at least one of the plurality of locks comprises a peg configured to extend from the holder and engage the first arm. 
     
     
         9 . The data storage device of  claim 8 , wherein the at least one of the plurality of locks comprises an electromagnetic coil configured to retract the peg from the first arm. 
     
     
         10 . The data storage device of  claim 8  comprising a helical spring configured to bias the peg toward the first arm. 
     
     
         11 . The data storage device of  claim 8 , wherein the plurality of locks is spaced along the holder at positions corresponding to the first plurality of upper disks. 
     
     
         12 . The data storage device of  claim 1 , comprising a movable ramp that is configured to move in unison with the first arm in the z direction parallel to the first portion of the actuator shaft. 
     
     
         13 . A data storage device comprising:
 a stack of a plurality of data storage disks, the stack comprising a first read/write surface defining an x-y plane and a second read/write surface parallel to the first read/write surface;   a first actuator shaft and a second actuator shaft aligned end-to-end and having a common longitudinal axis;   a first arm configured to move in a z direction along the first actuator shaft, the first arm having a first head end that is movable relative to the first read/write surface;   a first head supported by the first head end of the first arm, wherein the first head is configured to interact with the first read/write surface;   a first linear actuator configured to move the first arm along the first actuator shaft;   a plurality of locks spaced apart in the z direction and configured to retain the first arm in a selected one of a corresponding plurality of positions relative to the first actuator shaft;   a second arm movably attached to the second actuator shaft, the second arm having a second head end that is movable relative to the second read/write surface;   a second head supported by the second head end of the second arm, wherein the second head is configured to interact with the second read/write surface; and   a second linear actuator configured to move the second arm along the second actuator shaft independently of motion of the first arm along the first actuator shaft.   
     
     
         14 . The data storage device of  claim 13  comprising a first rotary actuator configured to pivot the first arm about the first actuator shaft. 
     
     
         15 . The data storage device of  claim 14  comprising a second rotary actuator configured to pivot the second arm about the second actuator shaft independently of motion of the first arm about the first actuator shaft. 
     
     
         16 . The data storage device of  claim 13  comprising a holder connected to the first portion of the actuator shaft. 
     
     
         17 . The data storage device of  claim 16 , wherein at least one of the plurality of locks comprises a peg configured to extend from the holder and engage the first arm. 
     
     
         18 . A method comprising:
 moving a first arm in a z direction along a longitudinal axis to position a first head of the first arm relative to a first plurality of data storage disks;   locking the first arm in the z direction along the longitudinal axis with one of a plurality of spaced locks; and   moving a second arm in the z direction along the longitudinal axis, independently of moving the first arm in the z direction, to position a second head of the second arm relative to a second plurality of data storage disks.   
     
     
         19 . The method of  claim 18  comprising:
 rotating the first arm about the longitudinal axis to position the first head relative to one of the first plurality of data storage disks; and 
 rotating the second arm about the longitudinal axis independently of rotating the first arm, to position the second head relative to one of the second plurality of data storage disks. 
 
     
     
         20 . The method of  claim 18 , wherein locking the first arm comprises mechanically engaging an end of the first arm with a holder.