Dynamic magnetic information storage or retrieval – Head mounting – Disk record
Reexamination Certificate
1999-03-18
2001-12-11
Klimowicz, William (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
Disk record
C360S234600
Reexamination Certificate
active
06330134
ABSTRACT:
The present invention relates to a head assembly for reading and/or writing information, which has a head slider positioned at a predetermined position with respect to a storage medium, and it also relates to storage devices such as magnetic disk devices (floppy disk devices, hard disk devices, etc.), optical disk devices and tape disk devices.
BACKGROUND OF THE INVENTION
The conventional storage device is constructed to rotate a disk so that a head slider is caused to float a small distance from the surface of the disk, enabling the head slider to move in the radial direction of the disk. This conventional head slider is generally provided with a head element for recording and/or reading information.
In current information storage devices using mageopolitical disks, the head slider has a magnetic head for reading and/or writing a bias magnetic field to/from the head slider. In addition, an optical head of an objective lens or luminous elements for leading the light to the disk can also be mounted upon the head slider.
Most types of head sliders are supported by suspensions having elasticity which allows for flexing of the head slider towards or away from the disk. The head slider floats a slight distance from the surface of the disk due to the action caused by the air flow generated on the rotating disk surface, i.e., the head floats due to the principles of dynamic air pressure bearings. Higher recording densities and increasing miniaturization are currently being achieved with disk devices, and head sliders are being designed for lower floating heights to achieve miniaturization and lighter weight. However, if the floating height of the slider is designed so that it is too low, the head slider comes into contact with the disk surface due to floating level fluctuations. Such a condition has not been a problem in the past, but eventually, the probability of the slider coming into contact with the disk will be too high, and reliability will reduced because of damage occurring to the head slider and/or the head element parts.
FIG.
1
(A) shows a prior art head assembly. The head assembly
20
is generally composed of a head slider
26
and a suspension
21
. The suspension
21
is formed by press punching one sheet of an SUS plate, and has an arm attaching surface
23
which is to be attached to an arm of the disk device. The arm attaching surface
23
is formed with an attaching hole
23
A, and is furnished with a spacer
23
B to ensure that the attaching strength is adequate.
The suspension
21
is also provided with a slider attaching portion
25
D for attaching the head slider
26
to the suspension
21
at the opposite end of the arm attaching surface
23
. The adhesion surface
26
T of the head slider
26
is firmly secured to the suspension
21
by means of an adhesive
22
coated on the slider attaching portion
25
D. The slider attaching portion
25
D is created by a generally U-shaped hole
25
formed around the perimeter thereof, and the slider attaching portion
25
D is supported by three connected beams
25
A,
25
B,
25
C.
The structure of this suspension
21
enables the head slider
26
to be responsive to the air flowing backwards, forwards, to the right, and to the left. However, since the suspension
21
is, as stated above, press-formed, it is often twisted in direction “a” or in direction “b” due to stresses created during forming. The slider attaching portion
25
D is, accordingly, affected by the twisting, though the arm attaching surface
23
of the disk device is designed to be positioned so that it is parallel to the disc surface. Furthermore, since the slider attaching portion
25
D and the adhesion surface
26
T of the head slider are planar, if the head slider
26
is attached to a twisted slider attaching portion
25
D, the head slider
26
will be inclined with respect to the disk surface.
In summary, when the slider attaching portion
25
D is twisted at an angle of &agr;/2 in direction “a” with respect to the attaching surface
23
, the surface
26
D of the head slider
26
facing the disk (in this case the lower surface of the slider) is inclined similar to plane
29
A of FIG.
1
(A). Thus, because of this inclination, there is a reduction in the floating height of the read/write element
26
A (which may be any type of element for reading and/or writing information to/from a disk). Additionally, the frequency of contact of the slider with the disk is also increased. These conditions often result in damage to the head, the suspension and/or the disk.
Conversely, when the slider attaching surface
25
D is twisted at an angle of &agr;/2 in direction “b” with respect to the attaching surface
23
, the surface
26
D of the head slider
26
facing the disk is inclined in a manner similar to plane
29
B. Thus, the floating height of the read/write element
26
A is increased, and the distance between the head and the recording film of the disk is increased so that the recording and/or reading characteristics are degraded.
FIG.
1
(B) shows a graph of the floating height of the head slider
20
along different portions of radius of the disk. Line
41
represents the case with no torsion existing in the suspension, and the floating height is constant from the inner side of the disk to the outer side and where the head slider floats at a predetermined height, irrespective of its position on the disk. Line
42
represents the case with torsion existing in the suspension, and where the floating height is reduced going from the inner side of the disk to the outer side, resulting in instability. Since the floating height of the head slider is lower than the designed value, the probability of the head slider coming into contact with the disk is increased. Thus, to secure the floating stability of the head slider, there should be no torsion in the suspension.
Accordingly, in view of the problems discussed above, an objective of the present invention is to provide a head assembly and a storage device which are capable of improving the floating stability of the head slider, as well as improving the reliability of the storage device. It is another objective of the invention to provide a head assembly and a storage device which can provide a highly precise parallel relationship between the surface of the head slider facing a storage medium and the attaching surface of the support plate at the disk device side.
BRIEF SUMMARY OF THE INVENTION
Briefly, with head assembly of the present invention, it is possible to arrange the surface of the head slider facing the disk to be parallel to the disk surface, even if there is some torsion or twisting in the suspension. The effects of torsion can be mitigated against by using a nonplanar or curved portion, on the suspension, for attaching the slider to the suspension. Alternatively, it is also possible to mitigate the effects of torsion by using a nonplanar or curved portion on the surface of the slider where it is attached to the suspension. As an additional alternative, it is also possible to have nonplanar or curved portions on both the suspension and the slider attaching surface. As a result of the nonplanar surface(s), the read/write element will be held at a predetermined distance from the recording film of the disk. Thus, the floating height of the head slider can be held at a constant distance from both the inner and outer sides of the disk. Accordingly, it is possible to enhance the recording and reading efficiency, durability, and reliability of the disk device by reducing the frequency of contact between the head slider and the disk.
More specifically, the present invention relates to a head assembly that includes a head slider with a read/write element for reading/recording information to/from a disk and a suspension for supporting the head slider. The suspension includes a generally planar sheet that extends in a longitudinal direction from a first end to second end and an arm attaching portion located near the first end of the generally planar sheet of said suspension. The arm attaching portion is adapted to be
Fujitsu Limited
Greer Burns & Crain Ltd.
Klimowicz William
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