Browse Prior Art Database

Original Publication Date: 2000-Apr-01
Included in the Prior Art Database: 2003-Jun-18

Publishing Venue



Figure 1: 3.5 inch form factor disk drive with 65mm outer diameter disks and dual actuators. Described is a dual actuator disk drive where each of the two actuator assemblies and voice coil motor assemblies are of similar design but located at substantially 180 degree position difference with respect to the rotating position of the disks (see Figure 1). Patents US5223993, US5293282 and US5343347 have shown dual actuator designs where there are two read/write heads that service a single disk surface. These have been proposed primarily to reduce access time via reduced actuator move time and reduced rotational latency. However, since read/write heads contribute significantly to disk drive cost, doubling the number of read/write heads is not cost effective. In the present design, only one read/write head services any one corresponding disk surface. In this way there is no redundancy of two or more read/write heads servicing any single disk surface. The advantage is improved actuator dynamics, reduced actuator inertia, and smaller disk to disk spacing, by having only one read/write head suspended on any one actuator arm. In this design, the non redundancy of read/write heads per disk surface can be achieved in one of two ways: 1) by one actuator servicing all bottom disk surfaces and the opposing actuator servicing all top disk surfaces, or 2) by having two identical actuator assemblies with pairs of arms (each arm with suspended read/write heads) which service a single disk where every other disk is serviced by one of the two dual actuators. The latter approach results in the dual actuators and VCMs (voice coil motors) being offset in the axial direction of the disks by the amount equal to the axial disk pitch (center to center distance between successive disks). Patent US5081552 shows a dual actuator design in which one actuator services all top disk surfaces and the other actuator services all bottom disk surfaces, but the actuators are not identical assemblies and the design does not allow ramp head load/unload as does the present disclosed design shown above. In addition, placing the VCMs in diagonally opposite corners of the hard disk drive maximizes the rotational inertial about the rotational axis of the disks of the disk drive. This is advantageous in reducing rotational operational vibration disturbances by lowering the frequency of rotational rigid body vibration where the servo can better correct for disturbances. The described design can be dual actuators as shown and described above or have a