Disc drive actuator arm assembly with outer arm z-height less than inner arm z-height

DETAILED DESCRIPTION An objective of the present invention is to achieve uniform gram load on the sliders throughout the actuator stack.
Another objective of the present invention is to allow the use of thin and lightweight actuator arms without degrading the performance of the servo motor and disc drive.
Accordingly, the invention promotes lower profile disc drive systems.
Another object of the invention is to achieve increased stability by aligning the resonances of the inner actuator arms with the resonances of the outer actuator arms close together along the frequency spectrum.
These and other objectives are achieved in accordance with the present invention.
An embodiment of the present invention calls for positioning the two outer actuator arms at a particular distance, called the optimum z-height, from the memory disc surface of their corresponding memory discs would shift outer actuator gram load.
Significantly, this optimum z-height differs from the z-height of the inner actuator arms and from the presumed z-height.
Additionally, the use of lightweight and thin material and identical dimensions for corresponding outer actuator arm components is possible for economic packaging of the disc drive system without sacrificing performance.
As long as the outer actuator arms are positioned at the optimum z-height, degradation of performance due to the gram load of the sliders on the outer arms being different than those of the inner arms is minimized.
Since the present invention uses lower mass and lower inertia actuator arms, stability increases, access speed increases, and power requirements to drive the arms decrease.