US3864747A — Multiple pack magnetic disk system

Claim 1

Independent Claim 173 words

A magnetic disk subsystem comprising: a plurality of packs of magnetic disks, a plurality of pack spindles, each pack of disks being mounted in nonremovable fashion on a spindle, a baseplate, the pack spindles being mounted on said baseplate with their axes parallel to one another and with the edges of disks of adjoining pack spindles in close proximity one to the other, one single rotary access mechanism including: a plurality of magnetic heads, a plurality of arrays of arms mounted for common rotation, one array for each of said disk packs, each array including arms carrying said magnetic heads into read/write relationship with the tracks of one pack of magnetic disks, a stationary shaft affixed to said baseplate to be parallel to and in the middle of said spindles, and a positioning rotor mounted for rotation on said shaft, said positioning rotor having a large diameter such that the periphery of said positioning rotor is in close proximity to the edges of said disks whereby the length of said arms is minimized.

Claim 2

Dependent Claim 173 words

A magnetic disk subsystem comprising: a plurality of packs of magnetic disks, a plurality of pack spindles, each pack of disks being mounted in nonremovable fashion on a spindle, a baseplate, the pack spindles being mounted on said baseplate with their axes parallel to one another and with the edges of disks of adjoining pack spindles in close proximity one to the other, one single rotary access mechanism including: a plurality of magnetic heads, a plurality of arrays of arms mounted for common rotation, one array for each of said disk packs, each array including arms carrying said magnetic heads into read/write relationship with the tracks of one pack of magnetic disks, a stationary shaft affixed to said baseplate to be parallel to and in the middle of said spindles, and a positioning rotor mounted for rotation on said shaft, said positioning rotor having a large diameter such that the periphery of said positioning rotor is in close proximity to the edges of said disks whereby the length of said arms is minimized.

Claim 3

Dependent Claim 81 words

The system recited in claim 1 wherein the interface between said positioning rotor and said shaft includes: a pair of preloaded bearings, and a sleeve which interacts thermal expansion differences between said shaft and bearings on one side and said positioning rotor on the other side, said sleeve having the same coefficient of thermal expansion as said shaft and bearings, said sleeve interacting different radial and axial expansion of said positioning rotor in order to keep preload of said bearings constant.

Claim 4

Dependent Claim 51 words

The system recited in claim 1 wherein each of said arms is a rigid extension from said positioning rotor, each rotor extension being created by a cut-out around a radius which matches the circumference of said disks to permit said rotor extensions to move between said disks while maintaining good rigidity.

Claim 5

Dependent Claim 26 words

The system recited in claim 1 wherein each of said arms has lightning holes to reduce the mass of said arms while maintaining the rigidity thereof.

Claim 6

Dependent Claim 34 words

The system recited in claim 1 wherein each of said arms is generally wedged-shaped with the base thereof being rounded where the base joins the positioning rotor to obtain good rigidity of said arms.

Claim 7

Dependent Claim 26 words

The system recited in claim 1 wherein each of said arms holds a pair of flextures, each carrying a magnetic head on the outer end thereof.

Claim 8

Dependent Claim 80 words

The system recited in claim 6 wherein said flextures are mounted above each other and are disposed between two recording disks, one carrying a head in read/write relationship with the surface of one of said disks and the other carrying a head in read/write relationship with the opposite surface of the other of said disks, and elastic elements between said pairs of flextures, said elastic elements equalizing the force applied by said heads to the opposed surfaces of said disks.

Claim 9

Dependent Claim 23 words

The system recited in claim 1 further comprising: an electromagnetic rotor actuator having an armature affixed on one end of said positioning rotor.

Claim 10

Dependent Claim 32 words

The system recited in claim 8 wherein said positioning rotor has a conical or other shaped increase in the opening at the other end of the armature to reduce the inertia thereof.

Claim 11

Dependent Claim 127 words

A magnetic disk subsystem comprising: a plurality of packs of magnetic disks, a plurality of pack spindles, each pack of disks being mounted on a spindle, said packs being disposed with the spindles parallel to one another and with the edges of disks in adjoining packs in close proximity one to the other, an access mechanism shaft mounted parallel to, and in the middle of said spindles, a plurality of magnetic heads, a single rotary access mechanism mounted on said shaft for rotation, said access mechanism including: arrays of arms carrying magnetic heads into read/write relationship with the tracks of each pack of magnetic disks, one array of arms being provided for each pack of disks, all of said arrays being commonly rotated by said access mechanism.

Claim 12

Dependent Claim 127 words

A magnetic disk subsystem comprising: a plurality of packs of magnetic disks, a plurality of pack spindles, each pack of disks being mounted on a spindle, said packs being disposed with the spindles parallel to one another and with the edges of disks in adjoining packs in close proximity one to the other, an access mechanism shaft mounted parallel to, and in the middle of said spindles, a plurality of magnetic heads, a single rotary access mechanism mounted on said shaft for rotation, said access mechanism including: arrays of arms carrying magnetic heads into read/write relationship with the tracks of each pack of magnetic disks, one array of arms being provided for each pack of disks, all of said arrays being commonly rotated by said access mechanism.

Claim 13

Dependent Claim 22 words

The system recited in claim 10 wherein there are four pack spindles further comprising a common drive motor for said four spindles.

Claim 14

Dependent Claim 73 words

The system recited in claim 10 further comprising: a common drive motor for said pack spindles, a timing belt interconnecting said motor with said plurality of pack spindles, said timing belt providing a nonslipping drive connection between all pack spindles so that the relative angular position of said disk packs doesn''t change with time and all disk packs have the same readout characteristics as one multiple high disk pack on one single spindle.

Claim 15

Dependent Claim 32 words

The system recited in claim 10 further comprising a common baseplate for said plurality of pack spindles, said plurality of pack spindles being permanently mounted in a nonremovable fashion on said baseplate.

Claim 16

Dependent Claim 67 words

The system recited in claim 10 wherein the magnetic surface on at least one of said magnetic disks is a servo surface, and a servo arm mounted for common rotation with said rotary access mechanism, said servo arm carrying a magnetic head in reading relationship to said servo surface so that the signal produced indicates the track location of the arms of each of said pack spindles.

Claim 17

Dependent Claim 30 words

The system recited in claim 10 wherein said shaft has a cantilever mounted at only one end thereof so that said disk packs are easily accessible for servicing and removing.

Claim 18

Dependent Claim 40 words

The system recited in claim 15 comprising: an air tight seal closing the opening of said positioning rotor on the end opposite to said cantilever to prevent circulation of air over the interface between said shaft and said positioning rotor.

Claim 19

Dependent Claim 24 words

The system recited in claim 15 wherein said shaft is of increased diameter toward the cantilever end thereby increasing the stiffness of said shaft.

Claim 20

Dependent Claim 157 words

A magnetic disk subsystem comprising: a plurality of packs of magnetic disks, a plurality of pack spindles, each pack of disks being nonremovably mounted on a spindle, a baseplate for said disk system, the pack spindles being mounted on said baseplate parallel to one another and with the edges of disks of adjoining pack spindles in close proximity one to the other, a plurality of magnetic heads, an access mechanism shaft mounted on said baseplate parallel to, and in the middle of said spindles, a single rotary access mechanism mounted for rotation on said shaft, said access mechanism including arrays of arms carrying magnetic heads into read/write relationship with the tracks of each pack of magnetic disks, and a plurality of shrouds, one for each pack of magnetic disks, said baseplate supporting a shroud enclosing each disk pack in a self-contained air chamber so that dirt and debris from one chamber cannot be transferred to another chamber.

Claim 21

Dependent Claim 157 words

A magnetic disk subsystem comprising: a plurality of packs of magnetic disks, a plurality of pack spindles, each pack of disks being nonremovably mounted on a spindle, a baseplate for said disk system, the pack spindles being mounted on said baseplate parallel to one another and with the edges of disks of adjoining pack spindles in close proximity one to the other, a plurality of magnetic heads, an access mechanism shaft mounted on said baseplate parallel to, and in the middle of said spindles, a single rotary access mechanism mounted for rotation on said shaft, said access mechanism including arrays of arms carrying magnetic heads into read/write relationship with the tracks of each pack of magnetic disks, and a plurality of shrouds, one for each pack of magnetic disks, said baseplate supporting a shroud enclosing each disk pack in a self-contained air chamber so that dirt and debris from one chamber cannot be transferred to another chamber.

Claim 22

Dependent Claim 87 words

The system recited in claim 18 wherein the recording disks of each pack are mounted on a disk base, said disk base having a larger coefficient of temperature expansion than said spindle shaft, and a cylindrical interface including a press fit between said disk base and each spindle shaft, the height of said press fit being at least as large as the diameter of said spindle shaft thereby assuring radial and angular stability of the relative position between the disk base and the spindle axis of rotation.

Claim 23

Dependent Claim 25 words

The system recited in claim 18 wherein each of said shrouds includes an outer half which is removable to allow access to said pack spindles.

Claim 24

Dependent Claim 36 words

The system recited in claim 18 further including an electromagnetic rotor actuator for moving said access mechanism comprising: an armature mounted for rotating said access mechanisms, and a plurality of stator magnets mounted in said baseplate.

Claim 25

Dependent Claim 44 words

The system recited in claim 21 wherein said housing provides a conical shaped opening at the sides of said magnets so that there is a bigger air gap at the top of each side of said magnets so that magnetic flux leakage is minimized.

Claim 26

Dependent Claim 56 words

The system recited in claim 21 further comprising: a cover with good magnetic conductivity positioned adjacent one side of said armature to close the magnetic circuits between adjoining magnets and to provide a narrow air path between said cover and said armature so that turbulent air flow can be induced over said armature for cooling purposes.

Claim 27

Dependent Claim 52 words

The system recited in claim 23 wherein said magnets are mounted on one side of said armature only so that the required length of the positioning rotor is minimized and said narrow air passage can be provided on the other side of said armature without plugging the sizable gaps between the magnets.

Claim 28

Independent Claim 108 words

The method of operating a multiple disk pack system in which packs of magnetic disks are mounted on parallel spindles with the edges of the disks in adjacent packs in close proximity one to the other comprising: concurrently rotating all of the disks on their respective spinDles through a nonslipping drive connection between all spindles, rotating an access mechanism carrying magnetic heads into read/write relationship with corresponding tracks on different disks in different packs, and electronically switching said magnetic heads during readout to read said blocks of data pertaining to common subject matter from all packs without changing the position of said magnetic heads from track to track.

Claim 29

Independent Claim 108 words

The method of operating a multiple disk pack system in which packs of magnetic disks are mounted on parallel spindles with the edges of the disks in adjacent packs in close proximity one to the other comprising: concurrently rotating all of the disks on their respective spinDles through a nonslipping drive connection between all spindles, rotating an access mechanism carrying magnetic heads into read/write relationship with corresponding tracks on different disks in different packs, and electronically switching said magnetic heads during readout to read said blocks of data pertaining to common subject matter from all packs without changing the position of said magnetic heads from track to track.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-02-03	1978-08-05	1979-02-04	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-02-03	1982-08-05	1983-02-04	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-02-03	1986-08-05	1987-02-04	$7700.00	Window Closed / Lapsed

Multiple pack magnetic disk system

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