Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Disk record
Reexamination Certificate
1998-08-26
2001-10-30
Sniezek, Andrew L. (Department: 2651)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Disk record
C360S097030
Reexamination Certificate
active
06310747
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to information storage devices such as rigid disk drives, and to rigid disk drives for pocket, palm-top, and laptop computers. The invention is also applicable, however, to information storage devices of various sizes.
2. Description of Prior Art
The continuing trend toward smaller portable computers has created the need for a new class of miniature information storage devices. Portable applications for information storage devices have resulted in increasingly severe environmental and physical requirements. Small size, low power consumption, environmental endurance, low cost and light weight are characteristics that must co-exist in these applications; they cannot be met by simple extensions of previous technology.
Many examples of miniaturized reduced “footprint” disk drives have been described in patents such as U.S. Pat. No. 4,568,988 to McGinley, et al, issued Feb. 4, 1986, Reexamination Certificate (953rd), U.S. Pat. No. B14,568,988, certificate issued Nov. 29, 1988, U.S. Pat. No. 4,933,785, issued Jun. 12, 1990 to Morehouse, et al. The rigid magnetic recording disk utilized in the device, described in McGinley, et al., had a diameter of approximately 3.5 inches. In the Morehouse, et al. device described in that patent, the rigid disks utilized in the drive had a nominal diameter of 2.5 inches. The “footprint” (width by length measurement) of the drive described in the above-noted Morehouse, et al. patent was described as being 2.8 inches by 4.3 inches. That is, the housing used to enclose the rigid disk drive was 2.8 inches wide and 4.3 inches long. A rigid disk drive of that size is generally applicable to computers having a size of 8.5 inches by 11 inches by 1 inch. Another patent describing a relatively small diameter disk was issued Jun. 18, 1991 to Stefansky, U.S. Pat. No. 5,025,335. Stefansky describes a 2½″ form factor disk drive utilizing a single rigid disk having a diameter of approximately 2.6 inches. However, these products do not provide the combination of features needed for “pocket,” “palm-top” and laptop computers.
History has shown that as disk drives become smaller and more efficient, new applications and uses for disk storage become practical. For example, using the disk drive as a circuit board assembly component requires further reduction in the physical size of the storage device as well as unique mounting strategies, issues addressed by this invention.
Use of disk drive storage devices in palm-top computers and small electronic devices, such as removable font cartridges for laser printers, require a level of vibration and shock resistance unobtainable with present large disk drives. These new applications require equipment to survive frequent drop cycles that result in unusually high acceleration and shock. It is well known that the force on an object is directly proportional to its mass, therefore reducing mass is an essential strategy for improving shock resistance.
Portable equipment also makes stringent demands on the durability and stability of the storage equipment under extreme dynamic, static, temperature and humidity stress. A device of small dimensions by its nature experiences less absolute temperature induced physical dimensional displacements. High humidity, especially during storage conditions, can aggravate a phenomenon known as “stiction” that occurs with conventional disk drives; the transducer head clings to the smooth disk surface, which can stall the spin motor and damage the heads.
The greater the power consumption, the larger and heavier the battery pack becomes. Hence, for a given operating time, power consumption is a primary and unavoidable design consideration for portable devices. In fact, the weight of a portable device is dependent on the total energy required to meet operational mission time. For disk drive equipment energy use is especially important during what is known as standby or power-down modes. Low power consumption also reduces parasitic heat, an important consideration in compact electrical equipment. Reducing the diameter and thickness of the information disk(s) can also provide significant reduction in power consumption during spin up. Modern disk drive power management methods use intelligent decision strategies, evaluating disk drive usage patterns to sequence power saving shut down features.
FIG. 24A
is a block diagram of a prior art servo field
2400
. The servo field
100
is the same length and includes, starting at its leading edge, a write splice sub-field
2401
, an automatic gain control (AGC) sub-field
2402
, a sector mark sub-field
2403
, an index sector identifier
2404
, a defect bit
2405
, a Gray code track number sub-field
2406
, and a track position sub-field
2407
followed by another write splice sub-field. Servo field
2400
is preceded and followed by data regions
2410
and
2411
, respectively. As explained more completely below, AGC sub-field
2402
is actually divided into two parts. The first part is a write-to-read transition zone and the second part provides the actual AGC data.
FIG. 24B
is a flat view of the magnetic dibits in one servo field in tracks
3
to
6
of the disk. The other servo fields and data fields have the same general structure as illustrated by the block diagram of FIG.
24
A.
FIG. 24C
is the signal pattern generated when the information in track
3
is read.
FIGS. 49A and 49B
illustrate two- and three-disk embodiments of HDAs incorporating the prior art low-profile architecture. The spacing between adjacent disks
4920
is approximately two times the space t required for a read/write read, or 3.0 mm, to provide space for the two read/write heads
4930
and
4931
disposed between the adjacent disks. Thus, each additional disk
4920
increases the thickness of the prior art HDA by 3.6 mm (two spaces t and 0.6 mm for the thickness of the additional disk). Therefore, the thickness of the two-disk, four-head HDA of
FIG. 49A
is approximately 17.2 mm, and the thickness of the three-disk, six-head HDA of
FIG. 49B
is approximately 20.8 mm. Ferrite shields
4940
are illustrated in both
FIGS. 49A and 49B
.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a rigid disk drive having reduced physical dimensions, but retaining the storage capacity of larger disk drives, with minimized power consumption and providing extreme resistance to shock and vibration.
A further object of the invention is to provide a disk drive having a 1¼ inch form factor. In accordance with the invention, a rigid disk drive information storage device is provided which has a base and cover, utilizes one or more information storage disks having a diameter of approximately 33.5 mm (1¼ inches) provides an information storage capacity of at least 20 Megabytes.
A disk drive in accordance with one embodiment of the present invention has a length of approximately 51 mm, a width of approximately 35 mm and a height of approximately 10 mm in a stacked configuration with an associated printed circuit board positioned beneath the disk drive. Included is a disk spin motor internal to the housing, and a rotary actuator for positioning read/write transducer elements over the surface of the disk for the recording and play-back of digital information.
In accordance with another feature of the invention, in one embodiment the transducer support arm of the disk storage device includes a lift tab which, when operated with a cam, provides a means to load or unload the head from the spinning surface of the recording disk as described in commonly assigned U.S. Pat. No. 5,289,325 issued Feb. 22, 1994 by James H. Morehouse et al., entitled “Rigid Disk Drive with Dynamic Head Loading Apparatus”, which is incorporated herein by reference in its entirety. In addition, a small form factor disk drive may not be able to produce enough torque to overcome stiction because of the low supply voltage and miniature spin motor component, thus making it impossible to start the disk ro
Blagaila John H.
Emo Bruce D.
Morehouse James H.
Utenick Michael R.
Heid David W.
Mobile Storage Technology Inc.
Skjerven Morrill & MacPherson LLP
Sniezek Andrew L.
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