Disk memory drives generally comprise rotating magnetic memory disks, transducer heads and a linear or pivotally mounted magnetically driven actuator assembly which supports and positions the magnetic transducer heads at the disk surfaces and provides bidirectional movement of the magnetic heads over the disk or disks. Such disk memories are very high precision units requiring close dimensional tolerances in manufacturing. They are complex and delicate mechanically. In application, information stored on the disk must be accessed at high speed. This requires track seeking at high speeds and with precision. Structures such as the magnetic head suspension assemblies must be light in weight to minimize inertia yet be structurally stable and rigid while providing spring loading of the head and head mobility for track seeking and track following purposes.
Prior art magnetic head suspension assemblies as seen in the U.S. Pat. Nos. 3,931,641, 4,620,251, 4,754,353 and 4,796,122 typically comprise a rigid arm of aluminum or other lightweight material which is usually a casting of single piece or integrated construction in a disk drive involving multiple disks. These castings are provided with projecting fingers or pads to which the ends of the individual load beams or flexures which carry the magnetic heads are secured. The load beams or flexures, as the name implies, are flexible and permit spring loaded movement of the magnetic head. This movement is required in order to follow disk axial motion. Also by this means, a predetermined preloading of the magnetic head slider rails against a disk surface is provided so that at disk rotational speed the head takes off and literally flies on the thin film of air clinging to and traveling with the surface of the disk. The magnetic head is attached to the free end of the flexure or load beam by means of a thin, lightweight spring material providing flexible mobility of the magnetic head in roll and pitch and stiffness in yaw.
As will be seen by reference to these patents, the arm which supports the flexure which is either mounted for linear or angular movement is a rigid arm of aluminum or other lightweight material as described in U.S. Pat. No. 3,931,641. When viewed with respect to the flexures, it is a large bulky heavy structure constituting the bulk of the magnetic head support and is the primary contributor to a high moment of inertia of the magnetic head suspension assembly.