Abstract: An actuator for a magnetic disk device causes movement of a magnetic head in the radial direction of a rotating magnetic disk. Although this magnetic head is floated above the magnetic disk by a stream of air induced by the rotation of the magnetic disk at a high speed, an excessively high velocity of the air stream causes excessive vibrations of a soft gimbal resiliently supporting the magnetic head. In the actuator of the present invention, a head arm supporting the magnetic head through the gimbal is formed with a wind-breaking projection preventing direct impingement of the air stream against the gimbal and magnetic head, thereby minimizing vibrations of the gimbal and magnetic head.

Abstract: A rotary actuator for a magnetic disc device for swinging a head arm to position a magnetic head mounted at an end of the head arm to a desired track of a magnetic disc is disclosed. Magnetic shield plates are provided to a magnetic circuit assembly which forms a voice coil motor together with a moving coil mounted at a rear end of a head carriage which supports the head arm in order to prevent leakage magnetic fluxes created in the vicinity of a permanent magnet of the magnetic circuit assembly from reaching the magnetic head.

Abstract: At the start of operation, a floating magnetic head is brought into contact with the surface of a magnetic disk and the magnetic disk is then rotated to float the magnetic head off the magnetic disk surface. At the end of operation, the floating magnetic head is drawn away from the magnetic disk surface of the rotating magnetic disk and, after the lapse of a certain period of time, the magnetic disk is stopped. This prevents the floating magnetic head from sticking to the magnetic disk owing to dew condensation, permits easy miniaturization of the floating space and provides for increased recording density.