Apparatus for positioning a magnetic head

• US 4,686,590 A
• Filed: 06/28/1985
• Issued: 08/11/1987
• Est. Priority Date: 06/29/1984
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Fujiki, Masao, Kunii, Shinpei
• Primary Examiner(s): Cardillo, Raymond F.
• Assistant Examiner(s): Garland, Steven R.
• Application Number:
  US06/749,726
• Time in Patent Office: 774 Days
• Field of Search: 360/69, 360/75, 360/77, 360/78, 360/97-99, 360/105, 360/106, 360/137
• US Class Current: 360/78.04
• CPC Class Codes: G11B 5/016 using magnetic foils
• CPC Class Codes: G11B 5/54 with provision for moving the head into or out of its operative position or across tracks

Abstract

An apparatus, primarily for use in battery-powered floppy disk drives, for moving a magnetic head radially toward a reference track in accordance with a direction signal from a disk controller. The apparatus comprises a track position sensor for sensing the track position of the magnetic head. The track sensor outputs a signal indicating whether the magnetic head is positioned radially inward or outward of track positions within a predetermined vicinity of a magnetic disk reference track. The apparatus has a reset circuit for generating a set signal when a power is applied to the reset circuit, and a logic circuit responsive to the track sensor output and set signal for providing a first binary control signal for use in selecting the direction of movement of said magnetic head. A second logic circuit utilizes the first binary control signal and the direction signal from the disk controller to provide a second binary control signal operative to set the direction of movement of the magnetic head. The direction of movement is set in accordance with the direction signal when the first binary control signal is in a first state and in accordance with a predetermined direction when the first binary control signal is in a second state. A moving mechanism moves the magnetic head in accordance with the second binary control signal.

Claims

1. An apparatus for moving a magnetic head, which is used in transferring data between an information system and an external magnetic disk, in a radial direction to a reference track of said magnetic disk in accordance with a direction signal from a magnetic disk controller, said apparatus comprising:

(a) track position sensing means for sensing a track position of said magnetic head with respect to said magnetic disk, said track position sensing means having an output indicating whether said magnetic head is positioned radially inward or outward of positions within a predetermined vicinity of said reference track;

(b) reset means for providing a set signal for a predetermined time commencing when a potential is applied to said reset means;

(c) first logic means responsive to said output of said track position sensing means and said set signal for providing a first binary control signal for use in selecting the direction of movement of said magnetic head;

(d) second logic means responsive to said direction signal from said magnetic disk controller and said first binary control signal for providing a second binary control signal operative to set the direction of movement for said magnetic head, said second binary signal being operative to set a direction of movement in accordance with said direction signal from said magnetic disk controller when said first binary control signal is in a first binary state, and being operative to set a direction of movement in accordance with a predetermined direction when said first binary control signal is in a second binary state; and

(e) means for moving said magnetic head in a radial direction in accordance with said second binary control signal.

2. The apparatus for moving a magnetic head of claim 1, wherein said first logic means comprises an R-S flip-flop device.

3. The apparatus for moving a magnetic head of claim 1, wherein said second logic means comprises an OR circuit device.

4. The apparatus for moving a magnetic head of claim 1, wherein power for said apparatus is supplied by a direct current power source.