Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
1998-12-15
2001-09-25
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S527200, C029S527400
Reexamination Certificate
active
06292996
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of data storage devices. More particularly, the present invention relates to plain carbon steel hubs for rotating removable data storage devices.
BACKGROUND OF THE INVENTION
Typical removable data storage devices rely on rotation of the data storage media about a hub to record and read data. Examples of such removable devices include magnetic data storage discs, magnetic data storage tape cartridges, and magneto-optical discs.
Removable magnetic data storage discs typically include a polyester resin or the like having a magnetic layer on each side thereof on which information is recorded by a magnetic head. Flexible magnetic data storage discs which have a diameter of 3½ inches (90 mm) or less are known as micro-floppy discs and will be referred to so herein. Generally, the micro-floppy disc is accommodated in a hard casing to form a cartridge.
The flexible magnetic data storage disc comprises a thin circular magnetic recording medium having a hub at its center. The hub serves as a means of rotating the recording media over recording heads. Typical hubs are made of AISI/SAE 430/431 tainless Steel because of its durability, corrosion resistance, and susceptibility to magnetic attraction. Some hubs are provided in uncoated stainless steel, while others have been coated with chrome or epoxy to enhance their appearance or wear properties.
The disc hub plays an important role in proper operation of the disc.
FIG. 1
is an exploded view of a typical micro-floppy disc drive spindle
10
and hub
20
, including an annular ring of magnetic media
21
attached to the hub
20
. The drive spindle
10
includes a center pin
12
and alignment pin
14
that is spring-loaded to be biased away from the center pin
12
. The center pin
12
is received in the center pin opening
22
of the hub
20
while the alignment pin is received in the alignment window
24
.
FIG. 2
is a top view of the hub
20
properly mounted on a drive spindle
10
in which the center pin
12
of the drive
10
is received in the center pin opening
22
and the alignment pin
14
is properly located in the alignment window
24
. As shown, the alignment pin
14
is urged towards the center pin
12
during rotation of the hub
20
(and attached recording media—not shown) by the window
24
. The drive spindle
10
is typically magnetized to attract the hub
20
towards the drive
10
during loading and use of the disc. Although proper seating and orientation of the hub on the drive typically occurs without fault, there are a number of errors which can occur that cause errors in the writing or reading of data from the media.
FIG. 3
depicts one error that can occur in seating of the hub
20
on drive spindle
10
. This error involves failure of the alignment pin
14
to properly seat in the alignment window
24
in hub
20
. As shown, the alignment pin
14
has only moved partially towards its proper position in the corner of the window
24
. This error prevents proper positioning of the recording media relative to the read/write heads in the disc drive. Errors of the this type are typically detected with a test commonly referred to as “Index to Data.”
FIGS. 4 and 5
depict another error in seating of the hub
20
on the drive spindle
10
. This error, referred to as a “mischuck,” results in lifting of the hub
20
off of the drive spindle
10
in the area of the alignment pin
14
. As a result, the hub
20
is canted on the drive spindle
10
and proper alignment of the media with respect to the read/write heads in the disc drive cannot be maintained. That improper alignment typically results in modulation errors as data is read from and written to the disc.
Similar concerns can plague manufacturers and users of other rotating removable data storage devices that incorporate a hub that mates with a spindle to rotate the data storage media, whether that media stores data magnetically or optically. Examples of such devices include removable magnetic data storage discs other than micro-floppy discs, removable magnetic data storage tape cartridges, and magneto-optical data storage discs.
Although the errors discussed above occur infrequently and are typically tested for by manufacturers of high quality removable data storage devices, any improvements that further reduce their incidence can be extremely valuable in terms of improved manufacturing yields in addition to increasing the reliability of the devices in use by purchasers.
SUMMARY OF THE INVENTION
The present invention provides a rotating removable data storage device having a hub of coated plain carbon steel. By using plain carbon steel for the hub a number of advantages are achieved by the present invention. The magnetic force generated between the drive spindle and the hub is typically increased, resulting in fewer mischucks. Also, the cost of the hubs is reduced because of the substitution of plain carbon steel for the stainless steel typically used. A coating over the plain carbon steel resists corrosion of the plain carbon steel hub and may also assist in preventing improper seating of the hub on the drive spindle. Additional vapor corrosion inhibiting layers may also improve the corrosion resistance for the coated plain carbon steel hubs.
In one aspect, the present invention provides a hub for a rotating removable data storage device having a core of plain carbon steel and a coating on at least a portion of the core. Preferably, the plain carbon steel comprises about 0.5% or less carbon, more preferably about 0.2% or less carbon. Some preferred coatings can be selected from the group consisting of tin, nickel, zinc, chrome, paints, epoxies, epoxy-urethanes, phenolic resins, and combinations thereof.
One hub according to the present invention is provided in a micro-floppy magnetic data storage disc.
In another aspect, the present invention comprises a micro-floppy magnetic data storage disc having a hub with a core of plain carbon steel and a coating on at least a portion of the hub. Preferably, the plain carbon steel comprises about 0.5% or less carbon, more preferably about 0.2% or less carbon. Some preferred coatings can be selected from the group consisting of tin, nickel, zinc, chrome, paints, epoxies, epoxy-urethanes, phenolic resins, and combinations thereof
In another aspect, the present invention comprises a hub for a rotating removable data storage device including a core comprising plain carbon steel; a primary coating on at least a portion of the core; and a vapor corrosion inhibiting layer on the primary coating. The vapor corrosion inhibiting layer may be an amine.
In another aspect, the present invention comprises a method of manufacturing a hub for a rotating removable data storage device comprising steps of forming a core of plain carbon steel; providing a primary coating on the core; and providing a vapor corrosion inhibiting layer on the primary coating. The step of providing the vapor corrosion inhibiting layer may include depositing the layer by aqueous solution, in vapor phase, or a combination of an aqueous solution and vapor phase deposition.
These and other features and advantages will be described in more detail below.
REFERENCES:
patent: 4063295 (1977-12-01), Mann et al.
patent: 4068271 (1978-01-01), Kok
patent: 4244788 (1981-01-01), Faulkner
patent: 4396887 (1983-08-01), Lenz
patent: 4398950 (1983-08-01), Gupta et al.
patent: 4757412 (1988-07-01), Iizuka et al.
patent: 4784881 (1988-11-01), Fiore et al.
patent: 4868699 (1989-09-01), Kingsbury et al.
patent: 4967184 (1990-10-01), Regelsberger
patent: 5051858 (1991-09-01), Jackson et al.
patent: 5057960 (1991-10-01), Shiba et al.
patent: 5077003 (1991-12-01), Muraoka et al.
patent: 5139700 (1992-08-01), Miksic et al.
patent: 5139889 (1992-08-01), Imazu et al.
patent: 5174025 (1992-12-01), Tasaki et al.
patent: 5214555 (1993-05-01), Hughes
patent: 5267390 (1993-12-01), Yang et al.
patent: 5270082 (1993-12-01), Lin et al.
patent: 5289456 (1994-02-01), Takahashi
patent: 5326645 (1994-07-01), Ashary et al.
patent: 53
Domonkos Richard E.
Hilton Ronald L.
Laska Gregory A.
Swanson John W.
Hughes S. Thomas
Imation Corp.
Levinson Eric D.
Omgba Essama
LandOfFree
Method of making a plain carbon steel hub for data storage... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of making a plain carbon steel hub for data storage..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of making a plain carbon steel hub for data storage... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2453805