Latch mechanism for disk drive using magnetic field of actuator magnets

• US 5,956,213 A
• Filed: 03/27/1996
• Issued: 09/21/1999
• Est. Priority Date: 01/25/1988
• Status: Expired due to Fees

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology plc (Seagate Technology Holdings Plc)
• Inventors: Dague, Wallis A., Stefansky, Frederick Mark
• Primary Examiner(s): Cao, Allen T.
• Application Number:
  US08/622,925
• Time in Patent Office: 1,273 Days
• Field of Search: 360/105, 360/106, 360/104, 360/98.01, 360/97.01, 360/97.02, 360/103, 364/200
• US Class Current: 360/256.2
• CPC Class Codes: G11B 21/02 Driving or moving of heads
• CPC Class Codes: G11B 21/083 on discs
• CPC Class Codes: G11B 25/043 using rotating discs
• CPC Class Codes: G11B 33/121 the apparatus comprising a single recording/reproducing device
• CPC Class Codes: G11B 33/1446 Reducing contamination, e.g. by dust, debris
• CPC Class Codes: G11B 5/4806 specially adapted for disk drive assemblies, e.g. assembly prior to operation, hard or flexible disk drives G11B5/488 - G11B5/54 take precedence
• CPC Class Codes: G11B 5/5521 across disk tracks spiral track following G11B5/596
• CPC Class Codes: G11B 7/08576 Swinging-arm positioners

Abstract

A parking device for an actuator in a storage device which includes a voice coil motor having a magnet, providing a magnetic field including a magnetic flux, and a coil coupled to the actuator. The parking device includes a magnetically permeable capture structure forming a path for the magnetic flux and generating a capture region, the capture region being a region of magnetic flux adjacent to the capture structure; and a capture member, having a face plate, coupled to the actuator such that the capture member enters the capture region to park the actuator when the actuator is in a park position. In a further aspect, the parking device includes a magnet structure supporting the magnet, having a top plate and a bottom plate, wherein the capture structure is positioned between the top and bottom plates and forms a magnetic circuit path for the magnetic flux with the magnet, and the top and bottom plates. In yet another aspect, the magnet structure comprises a support post member including an air gap to generate a fringe effect in the magnetic flux to provide the capture region and includes cavities such that the circuit path formed by the structure channels the magnetic flux to the gap.

Claims

1. A parking device for an actuator in a storage device, the storage device including a voice coil motor having a voice coil magnet, providing a magnetic field including a magnetic flux, and a coil coupled to the actuator, comprising:

a magnetically permeable capture structure receiving the magnetic flux from the voice coil magnet and including means for directing the magnetic flux adjacent to the capture structure; and

a capture member, having a face plate, coupled to the actuator such that the capture member enters the magnetic flux from the voice coil magnet to park the actuator when the actuator is in a park position and the face plate lies in contact with the capture structure.

2. The parking device according to claim 1 wherein the storage device includes a magnet structure supporting the magnet, having a top plate and a bottom plate, wherein the capture structure is positioned between the top and bottom plates and forms a magnetic circuit path for the magnetic flux with the magnet, and the top and bottom plates.

3. The parking device according to claim 2 wherein the magnet structure comprises a support post member including an air gap to generate a fringe effect in the magnetic flux to provide the capture region and includes cavities such that the circuit path formed by the structure channels the magnetic flux to the air gap.

4. An actuator assembly for a disk drive, said drive including at least one magnetic disk, comprising:

an arm assembly having a first end and a second end, said first end holding at least one read/write head, and said assembly rotating about an axis to position said at least one head with respect to the disk;

a voice coil magnet for providing a magnetic field, said magnet having a generally arcuate shape first major surface, said magnetic field having direction and magnitude;

a coil, provided on said second end of said arm assembly and positioned in the presence of said magnetic field such that a current passing through said coil generates a second magnetic field to position said actuator arm assembly with respect to said disk; and

parking means for securing the actuator in a secured position when no current is present in the coil, including;

a latch support structure including an air gap and being comprised of a magnetically permeable material positioned adjacent the voice coil magnet, such that the latch support structure channels magnetic flux provided by the voice coil magnet to an area in and around the air gap, the air gap being positioned adjacent to the second end of the arm assembly, and

a capture member coupled to the second end of the actuator which enters the magnetic flux around the air gap and contacts the latch support structure on a first side and a second side of the air gap to latch the actuator.

5. The voice coil actuator of claim 4 wherein the latch support structure includes a shunt which forms a parallel flux path for magnetic flux impinging the air gap.

6. The voice coil actuator of claim 4 wherein the gap has a width of about 0.012 inch.

7. The voice coil actuator of claim 4 wherein the magnetic flux of the magnet impinges upon the gap and forms a magnetic capture region through fringing about the gap, and wherein the actuator is latched when the capture pin enters the capture region and abuts the gap such that the flux passes through the capture pin forming a circuit between with pin and the mounting structure.

8. A disk drive responsive to a host computer, comprising:

a base plate;

a disk rotatably mounted on said base plate, said disk having a landing zone;

transducer means for reading information from and writing information on said disk;

an actuator arm pivotally supported on said base plate, said actuator arm having a first end for supporting said transducer means and a second end disposed on the opposite side of said pivotal support from said first end;

a magnetically permeable capture member mounted on said actuator arm;

a voice coil magnet for providing a magnetic field extending around said second end of said actuator arm, the magnetic field including magnetic flux;

a coil, supported by said second end of said actuator arm and lying in a plane substantially parallel to said disk, for passing an electric current in the magnetic field; and

a latch body mounted adjacent to the actuator arm, the latch body forming a magnetic circuit with the voice coil magnet and including an air gap defined by first and second portions, and in the magnetic circuit, the latch body magnetically interacting with said capture member when said capture member abuts said first and second portions, and said gap, to park said transducer means.

9. A disk drive according to claim 8 wherein said latch body further includes a shunt in parallel with the gap, the shunt providing a parallel magnetic path with the gap for the magnetic flux.

10. A disk drive according to claim 9 wherein said magnetic flux is substantially contained within the latch body and a portion of said magnetic flux extends a predetermined distance beyond said latch body at said gap into a capture region.