Power loss actuated magnetic latch system for head-arm assembly
US5495376A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 1994 |
| Grant date | Feb 27, 1996 |
| Priority date | — |
| Expiry date | Jun 29, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B21/22
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A latch mechanism, especially for use in a disk drive, includes a locking arm that rotates about a pivot and engages a slot on the moving member that is to be locked, such as a head-arm. In a fixed coil embodiment, a permanent magnet is attached to an inboard end of the locking arm within the windings of a coil. Ferrous elements are mounted between the coil and the pivot of the locking arm. The ferrous elements attract the permanent magnet to hold the locking arm securely in either a latching or an unlatching state. When the coil is energized, poles are induced in the ferrous elements such that one repels the permanent magnet away from its then current state into the opposite state, while the other ferrous element attracts the permanent magnet to the other state. The magnetic field of the coil simultaneously applies a pure torque to the locking arm. This torque rotates the locking arm so that the arm changes to its other state. In a moving coil embodiment, the coil and ferrous elements are attached to the inboard end of the locking arm, and fixed permanent magnets are mounted in a housing or yoke on either side of the coil. No external power is necessary to hold the locking arm in …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.