Single lever bi-directional inertia latch

Details Single lever bi-directional inertia latch Single lever bi-directional inertia latch

2000-11-01

2003-03-04

Tupper, Robert S. (Department: 2652)

Dynamic magnetic information storage or retrieval

Head mounting

For moving head into/out of transducing position

C360S256500

Reexamination Certificate

active

06529349

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an actuator arm latch for a hard disk drive.
2. Prior Art
Hard disk drives contain a plurality of transducers that are magnetically coupled to rotating magnetic disks. The transducers can write and read information onto the rotating disks by magnetizing and sensing the magnetic field of the disks, respectively. The transducers are integrated into heads that are part of a head gimbal assembly (HGA). The HGAs are typically attached to an actuator arm that is pivotally mounted to a base plate of the drive.
Information is typically stored within a plurality of data sectors. The data sectors are located within annular tracks of the disks. The actuator arm has a voice coil that is coupled to a magnet assembly mounted to the base plate. The voice coil and magnet assembly together define a voice coil motor. The voice coil motor can be energized to pivot the actuator arm and move the transducers to different annular tracks of the disks.
Hard disk drives can be integrated into computer systems that undergo rotational acceleration. For example, a drive may be integrated into a portable computer that is moved by the user during operation of the drive. Movement of the portable computer may induce a rotational acceleration of the disk drive. The rotational acceleration of the disk drive may cause the actuator arm to move about the drive and damage disk drive components. There have been developed a number of latches that secure the actuator arm and prevent undesirable arm movement. The latch is engaged when the heads are moved away from the disks.
FIG. 1
shows a magnetic latch
1
that can secure an actuator arm
2
. The magnetic latch
1
is adjacent to a magnet assembly
3
that is coupled to a voice coil
4
of the arm
2
. The actuator arm
2
includes a steel pin
5
that is magnetically attracted to the latch
1
. The attractive magnetic force maintains the position of the actuator arm
2
. The actuator arm
2
can only be separated from the latch
1
by providing enough current to the voice coil
4
to create a torque sufficient to overcome the magnetic force. This requires additional power for the hard disk drive, a criteria that is undesirable when used in a portable computer. Additionally, the use of a magnetic latch
1
may require complex actuator speed control that increases the software processing overhead of the drive.
FIGS. 2-4
show an inertia latch
10
that can secure an actuator arm
11
when the disk drive has clockwise rotational acceleration. The inertia latch
10
is normally biased in an open position away from the actuator arm
11
. When the disk drive is not writing or accessing information the actuator arm
11
is rotated to park the heads
12
on a ramp
13
. The arm
11
also engages a crash stop
14
. When the disk drive has a clockwise rotational acceleration the actuator arm
11
moves in a counterclockwise direction. The latch
10
also moves in a counterclockwise direction until a latch hook
15
extends into a notch
16
of the actuator arm
11
as shown in
FIG. 3
to secure the arm
11
.
As shown in
FIG. 4
, the latch
10
will move back to the open position when the disk drive is no longer rotationally accelerating. If the hard disk drive has a counterclockwise rotational acceleration, the actuator arm
11
will swing past the latch
10
in a clockwise direction and possibly land on the disks (not shown). This type of latch
10
will not secure the actuator arm
11
for counterclockwise rotational acceleration.
FIGS. 5-7
show a dual lever latch
20
which has a large latch arm
21
that can move a small latch arm
22
into an actuator arm
23
. The small latch arm
22
will engage the actuator arm
23
whether the disk drive has clockwise or counterclockwise rotational acceleration. When the disk drive is rotating in a clockwise direction the large latch arm
21
moves in a counterclockwise direction and a first latch pin
24
pulls the small latch arm
22
into the actuator arm
23
. When the disk drive is rotating in a counterclockwise direction the large latch arm
21
moves in a clockwise direction and a second latch pin
25
pushes the small latch arm
22
into the actuator arm
23
. The latch
20
will secure the arm
23
regardless of the rotational acceleration direction. This design requires multiple latch components that increases the complexity and cost of mass producing the disk drive.
BRIEF SUMMARY OF THE INVENTION
One embodiment of the present invention is a hard disk drive which has a latch that can engage an actuator arm. The latch has a first end that can engage a first latch portion of the actuator arm and a second end that can engage a second latch portion of the actuator arm.


REFERENCES:
patent: 5870256 (1999-02-01), Khanna et al.
patent: 5875075 (1999-02-01), Hickox
patent: 6091587 (2000-07-01), Hatch et al.

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