US3936880A — Bistable deflection separation of flexible disks

Claim 1

Independent Claim 204 words

In a data storage device including multiple centrally restrained flexible storage disks arranged in a stack for continuous rotation about a common axis, with fluid-permeable open spaces between recording surfaces of successive disks and with the disks bendable between their centers and peripheries while rotating to effect stable expansion and contraction of any selected space between recording surfaces of successive said disks suitable for providing random selective external transducing access to surfaces adjacent the selected space, the improvement comprising: pressure control apparatus for establishing a first fluid pressure condition, in a predetermined pressure range, in said spaces between said disks; said condition having the effect of allowing the rotation of said disks to be stabilized uniquely in discrete first and second rotational configurations characterized in that the disks are all evenly spaced and inaccessible in said first configuration and unevenly separated at one selected space in said second configuration rendering said selected space accessible to receive an external transducer; said condition characterized in that it does not permit the rotational positions of the disks to stabilize in configurations of separation intermediate said first and second configurations and thereby renders the disks subject to expansion manipulations to said second configuration by small transiently applied forces.

Claim 2

Dependent Claim 204 words

In a data storage device including multiple centrally restrained flexible storage disks arranged in a stack for continuous rotation about a common axis, with fluid-permeable open spaces between recording surfaces of successive disks and with the disks bendable between their centers and peripheries while rotating to effect stable expansion and contraction of any selected space between recording surfaces of successive said disks suitable for providing random selective external transducing access to surfaces adjacent the selected space, the improvement comprising: pressure control apparatus for establishing a first fluid pressure condition, in a predetermined pressure range, in said spaces between said disks; said condition having the effect of allowing the rotation of said disks to be stabilized uniquely in discrete first and second rotational configurations characterized in that the disks are all evenly spaced and inaccessible in said first configuration and unevenly separated at one selected space in said second configuration rendering said selected space accessible to receive an external transducer; said condition characterized in that it does not permit the rotational positions of the disks to stabilize in configurations of separation intermediate said first and second configurations and thereby renders the disks subject to expansion manipulations to said second configuration by small transiently applied forces.

Claim 3

Dependent Claim 50 words

A device as in claim 1 including means for effecting said expansion manipulation to said second configuration by momentarily touching edges of said disks at a said selected space while said disks are in said first evenly spaced configuration and said spaces between the disks have said first pressure condition.

Claim 4

Dependent Claim 32 words

A device as in claim 1 including means for effecting said expansion by momentarily varying said pressure condition at said selected space while the disks are in the evenly spaced first configuration.

Claim 5

Dependent Claim 17 words

A device as in claim 1 including means for effecting said expansion by momentarily displacing said disks.

Claim 6

Dependent Claim 36 words

A device as in claim 4 including means for accelerating the displacement motion of said disks during said expansion by decreasing said pressure below said first condition momentarily during said momentary expansion displacement of said disks.

Claim 7

Dependent Claim 11 words

A device as in claim 1 wherein said fluid is air.

Claim 8

Dependent Claim 77 words

A device as in claim 1 wherein said disks have aligned holes forming a continuous internal space connecting uniformly with said spaces between said disks and said apparatus comprises a source of fluid at a constant predetermined critical pressure for establishing said first condition and conduit means for conducting said fluid to said internal space for distribution to said open spaces between the disks for use in facilitating bending manipulations of said disks for said expansion displacements.

Claim 9

Dependent Claim 23 words

A device as in claim 7 wherein there is one said hole per disk encompassing the center of rotation of the respective disk.

Claim 10

Dependent Claim 25 words

A device as in claim 7 wherein there are plural said holes per disk and said holes are off-axis perforations having predetermined spacing and dimensions.

Claim 11

Dependent Claim 105 words

A device as in claim 7 including inflexible end plates at opposite ends of said stack rotating coaxially with said disks; one of said end plates having an opening communicating with said conduit means for conducting said fluid to said internal space for said distribution; said stack including small-diameter spacer members between successive said storage disks for establishing the contraction spacing of said storage surfaces of said disks in said first stable configuration; and including means movable externally relative to said disks for selectively effecting said expansion displacement to said second configuration by applying transient displacing force to said disks at a said selected space.

Claim 12

Dependent Claim 30 words

A device as in claim 10 for accelerating said expansion displacement by momentarily decreasing the supply of fluid at said end plate opening during the application of said displacing force.

Claim 13

Dependent Claim 104 words

A device as in claim 10 wherein: there is one said hole per storage disk encompassing the center of rotation of the respective disk; said spacer members have central holes aligned with said storage disk holes and radial passages; said spacer members and a storage disks are mounted via surfaces adjacent respective said holes on a hollow perforated rotating spindle containing said internal space and adapted to provide axial fluid flow between said one end plate opening and said radial passages of said spacers and thereby permitting radial fluid flow relative to said open spaces between said disks for centrifugal circulation by said disks.

Claim 14

Dependent Claim 44 words

A device as in claim 10 wherein said holes are off-axis perforations of predetermined dimensions in said storage disks, outlying the peripheries of said spacers and serving to conduct said fluid from said end plate opening directly to said open spaces between said disks.

Claim 15

Dependent Claim 47 words

A device as in claim 10 wherein said end plate opening is connected externally to a plurality of fluid supply conduits one of which is adapted to provide a continuous steady state supply of fluid at a pressure suitable for establishing said predetermined first fluid pressure condition.

Claim 16

Dependent Claim 30 words

A device as in claim 14 wherein another of said conduits is connectible transiently to a source of reduced pressure for accelerating said expansion during application of said displacing force.

Claim 17

Dependent Claim 49 words

A device according to claim 14 wherein another of said conduits is connectible transiently to a source of fluid at elevated pressure relative to said steady state supply for rendering said disks unstable in said second configuration and urging said disks from said second configuration to said first configuration.

Claim 18

Dependent Claim 53 words

A device as in claim 10 wherein the space selectively widened in said second configuration has a predetermined shape determined by the shapes of the rotational paths traced by recording surfaces of the adjacent storage disks, and wherein said shape is substantially uniform over a range of multiple said spaces subject to selection.

Claim 19

Dependent Claim 54 words

A device as in claim 17 wherein said paths traced by said recording surfaces adjacent a said selectively widened space are substantially flat parallel circular bands, when said adjacent recording surfaces are not displaced by transducing apparatus, and have sufficient separation to allow for unobstructed maneuvering of external transducing apparatus into the respective space.

Claim 20

Dependent Claim 65 words

A device as in claim 18 in which said fluid is air; said pressure control apparatus including a source of pressured air coupled to said end plate opening for supplying a continuous steady state flow of air which is circulatable through said open spaces by centrifugal action in manner suitable for establishing said first predetermined pressure condition and thereby facilitating widening displacement of said stack.

Claim 21

Dependent Claim 49 words

A device as in claim 19 including means for effectively coupling vacuum transiently to said end plate opening, by momentarily blocking off said steady state flow, in coordination with each said momentary application of displacing force, thereby accelerating the associated widening displacement of said disks to said second configuration.

Claim 22

Dependent Claim 34 words

A device as in claim 19 including means for momentarily coupling additional air at elevated pressure to said end plate duct to to restore said disks from said second configuration to said first configuration.

Claim 23

Dependent Claim 28 words

A device as in claim 19 wherein said means for effecting said displacement includes means for momentarily displacing peripheral edges of the storage disks at said selected space.

Claim 24

Dependent Claim 33 words

A device as in claim 19 wherein said means for effecting displacement includes means for momentarily varying the fluid flow condition in the selected space relative to all other spaces between said disks.

Claim 25

Dependent Claim 189 words

In a data storage device including an externally transported transducer and multiple coaxially stacked flexible storage disks having fixed center spacings and arranged for continuous stable rotation about a common axis, said disks separated by smaller diameter porous spacer disks narrower than said transducer and defining open spaces between storage surfaces, said storage and spacer disks having central openings forming a continuous internal space permeable to air flow through said spacers and in said open spaces between said storage disks, improved means for effecting random selective bending deflections of recording surfaces of said storage disks at any selected interface space between said surfaces in order to render said recording surfaces at said interface space accessible to said transducer comprising: means for conducting a steady state supply of air at predetermined pressure to said internal space for conditioning said storage disks to have bistable rotational stability such that a transitory force can be used to expand a said selected interface space quickly and with sufficiently predeterminate and stable form to accommodate an external transducer without obstruction and without specialized transducer positioning apparatus for varying transducer positioning at different interface positions.

Claim 26

Dependent Claim 189 words

In a data storage device including an externally transported transducer and multiple coaxially stacked flexible storage disks having fixed center spacings and arranged for continuous stable rotation about a common axis, said disks separated by smaller diameter porous spacer disks narrower than said transducer and defining open spaces between storage surfaces, said storage and spacer disks having central openings forming a continuous internal space permeable to air flow through said spacers and in said open spaces between said storage disks, improved means for effecting random selective bending deflections of recording surfaces of said storage disks at any selected interface space between said surfaces in order to render said recording surfaces at said interface space accessible to said transducer comprising: means for conducting a steady state supply of air at predetermined pressure to said internal space for conditioning said storage disks to have bistable rotational stability such that a transitory force can be used to expand a said selected interface space quickly and with sufficiently predeterminate and stable form to accommodate an external transducer without obstruction and without specialized transducer positioning apparatus for varying transducer positioning at different interface positions.

Claim 27

Dependent Claim 29 words

A device according to claim 24 further including: means aided by said steady state air supply for effecting stable expansional deflection of said recording surfaces at a selected interface.

Claim 28

Dependent Claim 31 words

A device according to claim 24 wherein said steady state air supply is maintained at a level conducive to stabilizing and flattening paths of rotation of said expansionally deflected recording surfaces.

Claim 29

Dependent Claim 28 words

A device according to claim 24 including means for momentarily supplying restorational air pressure to contractably deflect said expansionally deflected surfaces to produce contraction of the associated interface.

Claim 30

Dependent Claim 27 words

A device according to claim 26 including means for applying vacuum to said central openings synchronous with said expansional deflection for accelerating expansion of the associated interface.

Claim 31

Dependent Claim 175 words

In a data storage device: coaxial stabilization plates having constant spacing along a common axis; multiple flexible storage disks and spacers coaxially stacked between said plates and arranged for continuous rotation about said axis; centers of said plates, disks and spacers having fixed axial positions; said spacers providing predetermined open spaces between successive said disks for centrifugal air circulation useful to stabilize said rotation; said spaces being insufficient to permit unobstructed transducing access to recording surfaces of said disks; said plates permitting limited axial bending displacements of said disks, relative to any one said air circulation space, sufficient to widen said space for transducing access; means for supplying a predetermined steady state flow of air at a pressure below a predetermined critical level to said air circulation spaces between all said disks; means aided by said steady state flow for utilizing transitory force effects to cause stable bending displacements of the disks at successively selected said air circulation spaces, whereby each said selected space is stably and uniformly expanded for stable and uniform transducing access.

Claim 32

Dependent Claim 175 words

In a data storage device: coaxial stabilization plates having constant spacing along a common axis; multiple flexible storage disks and spacers coaxially stacked between said plates and arranged for continuous rotation about said axis; centers of said plates, disks and spacers having fixed axial positions; said spacers providing predetermined open spaces between successive said disks for centrifugal air circulation useful to stabilize said rotation; said spaces being insufficient to permit unobstructed transducing access to recording surfaces of said disks; said plates permitting limited axial bending displacements of said disks, relative to any one said air circulation space, sufficient to widen said space for transducing access; means for supplying a predetermined steady state flow of air at a pressure below a predetermined critical level to said air circulation spaces between all said disks; means aided by said steady state flow for utilizing transitory force effects to cause stable bending displacements of the disks at successively selected said air circulation spaces, whereby each said selected space is stably and uniformly expanded for stable and uniform transducing access.

Claim 33

Dependent Claim 28 words

A device according to claim 29 wherein disk recording surfaces separated by said bending displacement tend to rotate in substantially flat planar paths generally perpendicular to said axis.

Claim 34

Dependent Claim 20 words

A device according to claim 30 wherein at least one of said plates is arranged to rotate with said disks.

Claim 35

Dependent Claim 53 words

A device according to claim 30 wherein said disks have axially aligned holes, forming an internal air conduction space connecting with said spaces between said disks, and said air supplying means is arranged to supply air to said internal space from a source external to the space occupied by said disks and plates.

Claim 36

Dependent Claim 45 words

A device according to claim 32 wherein said disk holes are auto-ventilating off-axis performations and said air supplying means comprises at least one opening in at least one of said end plates for controllably admitting external air into the internal spaces formed by said perforations.

Claim 37

Dependent Claim 32 words

A device according to claim 33 wherein said air supplying means comprises means for momentarily varying the flow of air through said at least one plate opening to accelerate said bending displacement.

Claim 38

Dependent Claim 58 words

A device according to claim 32 wherein said aligned disk holes centrally encompass said axis, said spacers are porous and said air supplying means comprises a source of air coupled to said holes via a duct in an end said disk and wherein said air flow varying means comprises means for momentarily applying vacuum to said central holes.

Claim 39

Dependent Claim 41 words

A device according to claim 34 said varying means including means for applying vacuum to said axial air conduction space while initiating said bending displacement in order to accelerate the displacement and thereby reduce access time to said disk recording surfaces.

Claim 40

Dependent Claim 33 words

A device according to claim 35 said vacuum applying means being synchronized in operation with said bending displacement in order to accelerate the displacement and reduce access time to said disk recording surfaces.

Claim 41

Dependent Claim 5 words

In a data storage device:

Claim 42

Dependent Claim 5 words

In a data storage device:

Claim 43

Dependent Claim 226 words

multiple flexible storage disks and spacer disks coaxially stacked between confining and stabilizing end plates; said disks and plates arranged for continuous co-rotation about a common axis with recording surfaces of said disks subject to bistable rotation in contracted positions permitting low force triggered expansion of any interface of said stack; centers of said disks and plates having fixed axial positions; said spacer disks providing predetermined spaces between successive said storage disks which permit a predetermined steady state supply of air to circulate in said spaces by centrifugal action and stabilize and flatten the rotational paths of said recording surfaces in both said expanded and contracted positions; spaces between successive disks in said contracted positons being insufficient to permit unobstructed insertion of a transducing head therein; said plates being positioned to limit expansional deflection of said recording surfaces of said storage disks to allow expansion of at least one interface between successive disks sufficient for insertion of said head and thereby permit access to recording surfaces at said interface; said storage disks and plates having internal openings permitting distribution of said steady state supply of air via one of said plates to said spaces between said storage disks for bistabilizing the rotation of said recording surfaces; and means aided by said steady state circulation for effecting expansional deflection of said recording surfaces at a selected interface.

Claim 44

Dependent Claim 226 words

multiple flexible storage disks and spacer disks coaxially stacked between confining and stabilizing end plates; said disks and plates arranged for continuous co-rotation about a common axis with recording surfaces of said disks subject to bistable rotation in contracted positions permitting low force triggered expansion of any interface of said stack; centers of said disks and plates having fixed axial positions; said spacer disks providing predetermined spaces between successive said storage disks which permit a predetermined steady state supply of air to circulate in said spaces by centrifugal action and stabilize and flatten the rotational paths of said recording surfaces in both said expanded and contracted positions; spaces between successive disks in said contracted positons being insufficient to permit unobstructed insertion of a transducing head therein; said plates being positioned to limit expansional deflection of said recording surfaces of said storage disks to allow expansion of at least one interface between successive disks sufficient for insertion of said head and thereby permit access to recording surfaces at said interface; said storage disks and plates having internal openings permitting distribution of said steady state supply of air via one of said plates to said spaces between said storage disks for bistabilizing the rotation of said recording surfaces; and means aided by said steady state circulation for effecting expansional deflection of said recording surfaces at a selected interface.

Claim 45

Dependent Claim 47 words

A device as in claim 38 wherein said recording disks have off-center holes for conducting a steady state supply of air to said spaces between said recording surfaces; including means for admitting an additional supply of air to said holes for effecting contractional displacement of said disks.

Claim 46

Dependent Claim 79 words

A device as in claim 38 wherein said spacer disks are porous to radial air flow and said recording disks, spacer disks and end plate have aligned central openings permitting passage of air from said end plate to said spacer disks and through said spacer disks radially by centrifugal action into and through the spaces between said storage disk recording surfaces; said steady state air supply being coupled from a source of pressured air through said end plate opening.

Claim 47

Dependent Claim 70 words

A device as in claim 38 wherein said disks and end plate are rotated at high speeds in the rnage of 1100- 2400 rpm; and wherein said recording disks have outer diameters in the rane 8 - 15 inches and axial thickness measurements in the range 1-3 mils; and wherein said spacer disks have outer diameters less than 4 inches and axial thicknesses in the range 2 - 7 mils.

Claim 48

Dependent Claim 27 words

A device as in claim 41 wherein said recording disks have off-center holes for conducting steady state pressured air flow to said spaces between said recording surfaces.

Claim 49

Dependent Claim 72 words

A device as in claim 41 wherein said spacer disks are porous to radial air flow and said recording disks, spacer disks and end plate have aligned central openings permitting passage of air from said end plate to said spacer disks and through said spacer disks radially by centrifugal action into and through the spaces between said storage disk recording surfaces; said steady state air being supplied through said end plate opening.

Claim 50

Dependent Claim 18 words

A device in accordance with claim 39 wherein said means for admitting additional air comprises a movable plate.

Claim 51

Dependent Claim 120 words

In a data storage device, in which multiple interfacing flexible storage disks arranged in a packed configuration for continuous co-rotation in an environmental fluid are maintained in an aerodynamically balanced pressure state and caused to be intermittently deflected at selected interface positions for transducing access, a deflection control method comprising: establishing a predetermined critical state of disturable pressure balance in said fluid while the storage disks are rotating in an undeflected configuration; and deflecting said disks into a stable separated configuration by creating a momentary pressure imbalance in said fluid, relative to a selected interface, which operates in conjunction with the existence of said critical pressure state to exert a stable deflecting influence on the rotational orbits of the disks.

Claim 52

Dependent Claim 120 words

In a data storage device, in which multiple interfacing flexible storage disks arranged in a packed configuration for continuous co-rotation in an environmental fluid are maintained in an aerodynamically balanced pressure state and caused to be intermittently deflected at selected interface positions for transducing access, a deflection control method comprising: establishing a predetermined critical state of disturable pressure balance in said fluid while the storage disks are rotating in an undeflected configuration; and deflecting said disks into a stable separated configuration by creating a momentary pressure imbalance in said fluid, relative to a selected interface, which operates in conjunction with the existence of said critical pressure state to exert a stable deflecting influence on the rotational orbits of the disks.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1979-02-02	1979-08-04	1980-02-03	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1983-02-02	1983-08-04	1984-02-03	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1987-02-02	1987-08-04	1988-02-03	$7700.00	Window Closed / Lapsed

Bistable deflection separation of flexible disks

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