Abstract: An actuator for a magnetic disk drive includes a planar coil which is symmetrical with respect to the center of rotation and has substantially straight active sections extending from the center of rotation on opposite sides of the center of rotation. Four permanent magnets provide a magnetic field. When current is applied to the planar coil, magnetic forces rotate the coil, and an attached actuator arm, about the center of rotation. The symmetrical coil sections eliminate or reduce torsional forces thereby avoiding vibration, improving bearing life and reducing potential servo loop instability.

Abstract: An improved Bernoulli plate for juxtaposition to a rotating flexible magnetic disk so that the disk is rendered substantially rigid by a vacuum formed by the air between the plate and the disk being urged outwardly under the influence of centrifugal force is disclosed. The plate is formed by coining a metal substrate and thereafter electroplating the coined substrate so that any sharp irregularities resulting from the coining operation are smoothed, while the surface is provided with a hard, wear-resistant coating.