US3882541A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotating memory accessing mechanism
Assignee: International Business Machines Corp
•
Filing: 1974-01-25
•
Granted: 1975-05-06
•
Expires: 1994-01-25
Abstract
Abstract A system for recording and reproducing data streams in continuous or segmented form on a rotating buffer memory comprises a pair of head accessing mechanisms that are alternately shifted from track to track in synchronism with the rotation of the disk, such that one head is always available for data transfer. The mechanism provides high speed, but stable, shifting between tracks, by a cam arrangement driven by a stepping motor and in turn controlling the head accessing mechanism. The cam comprises a low mass, low inertia disk having a peripheral cam surface with a periodic progression of alternating dwell and ramp portions spaced in accordance with the stepping motor increments. Flexural members urge support devices for the head mechanisms in a direction to maintain cam followers in engagement with the cam surface and insure precise head positioning while filtering out vibrations and eliminating resonances induced by the stepping motor and associated system.
Inventors
- 👤 Sanjoy Ghose
- 👤 Paul A Gilovich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:50
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/54; G11B5/55; G11B5/5521; G11B5/5526; G11B5/553; G11B5/5547
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
115 words
A disk file accessing system for advancing a magnetic head assembly to successive tracks comprising: a head assembly support device coupled to said magnetic head assembly for movement substantially along a selected axis; cam follower means coupled to said support device; cam means having a peripheral cam surface adjacent said cam follower defining circumferential increments at varying radii from a selected axis of rotation; motor means coupled to rotate said cam means about said axis of rotation in incremental movements corresponding to the circumferential increments; and flexural means coupled to and supporting said support device and disposed to mechanically bias said cam follower means into engagement with the peripheral cam surface of said cam means.
Claim 2
Dependent Claim
115 words
A disk file accessing system for advancing a magnetic head assembly to successive tracks comprising: a head assembly support device coupled to said magnetic head assembly for movement substantially along a selected axis; cam follower means coupled to said support device; cam means having a peripheral cam surface adjacent said cam follower defining circumferential increments at varying radii from a selected axis of rotation; motor means coupled to rotate said cam means about said axis of rotation in incremental movements corresponding to the circumferential increments; and flexural means coupled to and supporting said support device and disposed to mechanically bias said cam follower means into engagement with the peripheral cam surface of said cam means.
Claim 3
Dependent Claim
48 words
The invention as set forth in claim 1 above, wherein the cam means comprises a low mass, low inertia disk and the peripheral cam surface comprises a progression of regularly varying alternating dwell and transition portions, the dwell portions lying at different radii from the axis of rotation.
Claim 4
Dependent Claim
103 words
The invention as set forth in claim 1 above, wherein said flexural means comprises at least two substantially like laminated planar flexure elements, each of which has a principal plane substantially normal to the selected axis, said elements being spaced apart along the selected axis and each having one end coupled to said support device and the other end coupled to the head assembly support device at a region substantially along the selected axis, such that for different curvatures of the flexure elements the head assembly is maintained in a plane substantially parallel to the disk and moved substantially along the selected axis.
Claim 5
Dependent Claim
48 words
The invention as set forth in claim 3 above, wherein said flexural means comprises a pair of laminated flexural members, each coupled to a different end of said head assembly support device, and each comprising at least two resilient layers and at least one elastomeric damping layer therebetween.
Claim 6
Dependent Claim
46 words
The invention as set forth in claim 4 above, wherein said laminated flexural members are each rectangular in their principal plane, and are disposed to urge said cam follower means against said cam means through a selected distance with a force between 0.5 and 2.0 lbs.
Claim 7
Dependent Claim
58 words
The invention as set forth in claim 1 above, wherein said flexural means comprises an elongated element mounted at one end thereof for pivoting movement about an axis and having the support device mounted thereon adjacent the other end thereof, and spring means coupled to the elongated element and biasing the elongated element relative to the pivot axis.
Claim 8
Independent Claim
130 words
A system for moving a magnetic head assembly relative to a rotary magnetic member comprising: carriage means capable of undergoing linear motion relative to the rotary member along an axis of motion and coupled to support the magnetic head assembly in operative relation thereto; rotatable cam means rotatable about an axis of rotation adjacent the axis of motion of the carriage means, the rotatable cam means engaging the carriage means and including position defining cam surfaces thereon establishing different head positions relative to said rotary magnetic member; and flexure means supporting said carriage means for movement relative to the rotary member and disposed to exert force against said carriage means in a direction tending to maintain said carriage means and cam means in engagement during rotation of said cam means.
Claim 9
Independent Claim
130 words
A system for moving a magnetic head assembly relative to a rotary magnetic member comprising: carriage means capable of undergoing linear motion relative to the rotary member along an axis of motion and coupled to support the magnetic head assembly in operative relation thereto; rotatable cam means rotatable about an axis of rotation adjacent the axis of motion of the carriage means, the rotatable cam means engaging the carriage means and including position defining cam surfaces thereon establishing different head positions relative to said rotary magnetic member; and flexure means supporting said carriage means for movement relative to the rotary member and disposed to exert force against said carriage means in a direction tending to maintain said carriage means and cam means in engagement during rotation of said cam means.
Claim 10
Independent Claim
167 words
A system for moving a magnetic head assembly relative to a rotary magnetic member comprising: carriage means movable relative to the rotary member and coupled to support the magnetic head assembly in operative relation thereto; rotatable cam means engaging the carriage means and including position defining cam surfaces thereon establishing different head positions relative to said rotary magnetic member, said cam surfaces defining a progression of alternating dwell and transition portions at regular increments; flexure means supporting said carriage means for movement relative to the rotary member and disposed to exert force against said carriage means in a direction tending to maintain said carriage means and cam means in engagement during rotation of said cam means, said flexure means comprising at least a pair of damped planar flexure members each having one end coupled to said carriage means and the other end fixed and spaced apart from said carriage means; and means for incrementally rotating said cam means in increments corresponding to the cam surface variations thereon.
Claim 11
Independent Claim
167 words
A system for moving a magnetic head assembly relative to a rotary magnetic member comprising: carriage means movable relative to the rotary member and coupled to support the magnetic head assembly in operative relation thereto; rotatable cam means engaging the carriage means and including position defining cam surfaces thereon establishing different head positions relative to said rotary magnetic member, said cam surfaces defining a progression of alternating dwell and transition portions at regular increments; flexure means supporting said carriage means for movement relative to the rotary member and disposed to exert force against said carriage means in a direction tending to maintain said carriage means and cam means in engagement during rotation of said cam means, said flexure means comprising at least a pair of damped planar flexure members each having one end coupled to said carriage means and the other end fixed and spaced apart from said carriage means; and means for incrementally rotating said cam means in increments corresponding to the cam surface variations thereon.
Claim 12
Independent Claim
199 words
A system for moving a magnetic head assembly from track to track relative to a magnetic disk comprising: carriage means movable substantially along a selected axis relative to the disk and coupled to support the magnetic head assembly in operative relation thereto; at least one cam disk rotatable in a plane parallel to the selected axis and including a circumferentially varying incremental pattern at a periphery thereof, different peripheral increments thereon corresponding to different desired track positions; incremental stepping motor means coupled to said cam disk for rotating said cam disk in increments corresponding to those of the incremental pattern; cam follower means coupled to said carriage means and disposed along a selecTed radius adjacent the periphery of said cam disk and in engagement with said cam disk on a side away from the magnetic disk; and planar flexure means including resonance damping means and lying substantially normal to the plane of said cam disk, said planar flexure means supporting said carriage means for movement along the selected axis and being under flexure to maintain said cam follower means against said cam disk during rotation thereof, whereby stepping motor vibrations are minimized in movement of the magnetic head assembly.
Claim 13
Independent Claim
199 words
A system for moving a magnetic head assembly from track to track relative to a magnetic disk comprising: carriage means movable substantially along a selected axis relative to the disk and coupled to support the magnetic head assembly in operative relation thereto; at least one cam disk rotatable in a plane parallel to the selected axis and including a circumferentially varying incremental pattern at a periphery thereof, different peripheral increments thereon corresponding to different desired track positions; incremental stepping motor means coupled to said cam disk for rotating said cam disk in increments corresponding to those of the incremental pattern; cam follower means coupled to said carriage means and disposed along a selecTed radius adjacent the periphery of said cam disk and in engagement with said cam disk on a side away from the magnetic disk; and planar flexure means including resonance damping means and lying substantially normal to the plane of said cam disk, said planar flexure means supporting said carriage means for movement along the selected axis and being under flexure to maintain said cam follower means against said cam disk during rotation thereof, whereby stepping motor vibrations are minimized in movement of the magnetic head assembly.
Claim 14
Dependent Claim
111 words
The invention as set forth in claim 9 above, wherein the peripheral incremental pattern of said cam disk comprises a progression of alternating dwell and inclined transition portions, each dwell portion corresponding to a different radial track position of the head relative to the disk, and each inclined portion defining a transition between adjacent tracks, said cam disk comprising a thin low mass, low inertia disk and said planar flexure means comprising a pair of spaced apart laminates including resilient and damping layers mechanically biasing said cam follower means against said cam disk with forces lying in a selected force range for a given extent of travel of the head assembly.
Claim 15
Dependent Claim
145 words
In a rotating disk file having a pair of magnetic head accessing mechanisms disposed to move along substantially parallel axes to different data tracks on the disk, a mechanism for alternately shifting the head mechanisms to successive tracks comprising: a pair of carriage means movable along the respective axes and each coupled to and supporting a different head mechanism; a pair of flexure mechanisms each separately supporting and biasing the individual carriage means; cam follower means mounted on and extending from each of the carriage means; stepping motor means; and cam means coupled to said stepping motor means and engaging each of said cam follower means, said cam means including cam surfaces in engagement with each of said cam follower means, said cam surfaces being configured to alternately step said cam follower means and associated carriage means for each step of said stepping motor means.
Claim 16
Dependent Claim
145 words
In a rotating disk file having a pair of magnetic head accessing mechanisms disposed to move along substantially parallel axes to different data tracks on the disk, a mechanism for alternately shifting the head mechanisms to successive tracks comprising: a pair of carriage means movable along the respective axes and each coupled to and supporting a different head mechanism; a pair of flexure mechanisms each separately supporting and biasing the individual carriage means; cam follower means mounted on and extending from each of the carriage means; stepping motor means; and cam means coupled to said stepping motor means and engaging each of said cam follower means, said cam means including cam surfaces in engagement with each of said cam follower means, said cam surfaces being configured to alternately step said cam follower means and associated carriage means for each step of said stepping motor means.
Claim 17
Dependent Claim
59 words
The invention as set forth in claim 11 above, wherein the flexure mechanisms each comprise a pair of laminated plates having both resilient and damping layers, each pair of plates lying in spaced apart parallel relation and having one end fixed at a region spaced from the associated carriage means and the other end coupled to the carriage means.
Claim 18
Dependent Claim
69 words
The invention as set forth in claim 12 above, wherein said cam means comprises at least one flat disk means having a peripheral cam surface with an incremental varying pattern of dwell and transition surfaces, the incremental circumferential spacing of said surfaces corresponding to the steps of a stepping motor means and the dwell surfaces being at different radii relative to the axis of rotation of said cam means.
Claim 19
Dependent Claim
80 words
The invention as set forth in claim 13 above, wherein the cam means comprises a single cam engaging both cam followers, said cam followers being spaced apart relative to the cam by an odd number of cam stepping surfaces and wherein the flexure plates have a flexural curvature relative to a fixed base axis that is normal to the plane of the disk, such that the head assemblies move in a plane parallel to the disk as the plates flex.
Claim 20
Dependent Claim
93 words
The invention as set forth in claim 13 above, wherein the cam means comprises a pair of cams having successive dwell and transition surfaces corresponding to the stepping distance of said stepping motor means, one cam follower means being positioned to move along a flat portion while the other moves along a transition portion, and wherein the flexure plates have a flexural curvature relative to a fixed base axis that is parallel to the plane of the disk such that the head assemblies move parallel to a fixed axis as the plates flex.
Claim 21
Dependent Claim
88 words
The invention as set forth in claim 11 above, wherein the said head acceSsing mechanisms are disposed on opposite sides of the disk, wherein said head accessing mechansims include head arms extending from said carriage means for tending to maintain the magnetic heads therein in air bearing relation to the disks, and wherein said system further includes head loading cam means disposed between said head accessing mechanisms for moving said head accessing mechanisms away from the disk, to disengage the heads from air bearing relation to the disk.
Claim 22
Dependent Claim
197 words
A disk file system for providng substantially continuous read/write functions for a data stream comprising: a magnetic disk rotating about a central axis at a selected rate; a pair of magnetic head assemblies disposed in operative relation with different recording surfaces of said magnetic disk; means for shifting said magnetic head assemblies from track to track in operative relation to the associated recording surfaces of the said magnetic disk, said means operating to shift the magnetic head assemblies alternately during successive revolutions of said magnetic disk and including a pair of carriage means supporting the magnetic head assemblies, rotatable cam means engaging the carriage means and having an outer periphery comprising different segments having different radial distances from an axis of rotation of the cam means, motor means coupled to rotate said cam means about the axis of rotation in incremental movements corresponding to the different segments, and means for mechanically biasing the carriage means into engagement with the outer periphery of the cam means; switching means coupled to provide data paths alternately to said magnetic head assemblies; and means for controlling said switching means in synchronism with the shifting of position of said magnetic head assemblies.
Claim 23
Dependent Claim
197 words
A disk file system for providng substantially continuous read/write functions for a data stream comprising: a magnetic disk rotating about a central axis at a selected rate; a pair of magnetic head assemblies disposed in operative relation with different recording surfaces of said magnetic disk; means for shifting said magnetic head assemblies from track to track in operative relation to the associated recording surfaces of the said magnetic disk, said means operating to shift the magnetic head assemblies alternately during successive revolutions of said magnetic disk and including a pair of carriage means supporting the magnetic head assemblies, rotatable cam means engaging the carriage means and having an outer periphery comprising different segments having different radial distances from an axis of rotation of the cam means, motor means coupled to rotate said cam means about the axis of rotation in incremental movements corresponding to the different segments, and means for mechanically biasing the carriage means into engagement with the outer periphery of the cam means; switching means coupled to provide data paths alternately to said magnetic head assemblies; and means for controlling said switching means in synchronism with the shifting of position of said magnetic head assemblies.
Claim 24
Dependent Claim
227 words
A disk file system for providing substantially continuous read or write functions comprising: a magnetic disk rotating about a central axis; a pair of parallel magnetic head assemblies extending substantially along given radii of said disk but on opposite sides thereof; a pair of carriage means each movable substantially parallel to the given radii and each coupled to provide a cantilever support base for a different one of said magnetic head assemblies; a pair of cam followers, each mounted on a different one of said carriage means and each extending normal to the given radii; stepping motor means having an axis of rotation parallel to said cam followers; cam means coupled to said stepping motor means and rotating therewith about an axis of rotation, said cam means having at least one peripheral cam surface engaging said cam followers and having an incrementally varying cam surface for alternately shifting said head assemblies by incremental amounts along the given radii for each step of said stepping motor; signal switching means in circuit with both of said magnetic assemblies for alternately coupling each of said magnetic head assemblies on a common data path in synchronism with the rotation of said disk and with the stepping of said head assemblies; and means responsive to the rotaiton of said disk for stepping said head assemblies alternately for each rotation of said disk.
Claim 25
Dependent Claim
227 words
A disk file system for providing substantially continuous read or write functions comprising: a magnetic disk rotating about a central axis; a pair of parallel magnetic head assemblies extending substantially along given radii of said disk but on opposite sides thereof; a pair of carriage means each movable substantially parallel to the given radii and each coupled to provide a cantilever support base for a different one of said magnetic head assemblies; a pair of cam followers, each mounted on a different one of said carriage means and each extending normal to the given radii; stepping motor means having an axis of rotation parallel to said cam followers; cam means coupled to said stepping motor means and rotating therewith about an axis of rotation, said cam means having at least one peripheral cam surface engaging said cam followers and having an incrementally varying cam surface for alternately shifting said head assemblies by incremental amounts along the given radii for each step of said stepping motor; signal switching means in circuit with both of said magnetic assemblies for alternately coupling each of said magnetic head assemblies on a common data path in synchronism with the rotation of said disk and with the stepping of said head assemblies; and means responsive to the rotaiton of said disk for stepping said head assemblies alternately for each rotation of said disk.
Claim 26
Independent Claim
145 words
A system for advancing a magnetic head assembly from track to track relative to a recording member comprising: a pivot arm rotatable about a selected axis normal to the plane of movement desired for the head assembly; a planar cam disk mounted in a plane parallel to the desired plane of movement and adjacent the pivot arm; cam follower means mounted adjacent the free end of the pivot arm and in engagement with the periphery of the cam disk, the cam disk periphery having incrementally spaced surfaces at different radii from an axis of rotation of define separate head assembly track positions; stepping motor means including a shaft driving the cam disk about the axis of rotation in increments corresponding to the peripheral increments; and Spring means engaging said pivot arm and tending to maintain the cam follower in engagement with the cam disk periphery.
Claim 27
Independent Claim
145 words
A system for advancing a magnetic head assembly from track to track relative to a recording member comprising: a pivot arm rotatable about a selected axis normal to the plane of movement desired for the head assembly; a planar cam disk mounted in a plane parallel to the desired plane of movement and adjacent the pivot arm; cam follower means mounted adjacent the free end of the pivot arm and in engagement with the periphery of the cam disk, the cam disk periphery having incrementally spaced surfaces at different radii from an axis of rotation of define separate head assembly track positions; stepping motor means including a shaft driving the cam disk about the axis of rotation in increments corresponding to the peripheral increments; and Spring means engaging said pivot arm and tending to maintain the cam follower in engagement with the cam disk periphery.
Claim 28
Dependent Claim
31 words
The invention as set forth in claim 19 above, wherein the spring means comprises an arcuate spring element having one end engaging said pivot arm and the other end being fixed.
Claim 29
Dependent Claim
54 words
The invention as set forth in claim 19 above, further including: a frame adjacent said cam disk and supporting said stepping motor; a member mounted on said frame for receiving the free end of said spring means; and a bracket mounted on the pivot arm for receiving the associated end of said spring means.
Claim 30
Dependent Claim
29 words
The invention as set forth in claim 21 above, wherein said frame and said bracket include slots for receiving the associated end of the spring means in disengageable relation.
Claim 31
Independent Claim
352 words
A system for supporting and maintaining a pair of magnetic head mechanisms in air-bearing relation to a rotating magnetic disk disposed in a given plane and comprising: a frame mechanism having upper and lower spaced apart portions for disposition adjacent a magnetic disk; a pair of planar cam disks disposed in planes substantially parallel to the magnetic disk and spaced apart proximate the frame mechanism between the upper and lower portions thereof, the cam disks each including a circumferential pattern of alternating dwell and transition portions, the dwell portions being at different radii from the axis of rotatioon of the disk in a progressive pattern, each radii defining a different track position on the magnetic disk; stepping motor means mounted on the upper portion of the frame mechanism and including a shaft extending between the upper and lower portions and engaged to drive said spaced apart cam disks, and including bearing means disposed in the lower portion of the frame mechanism for supporting the terminal portion of the stepping motor shaft, the stepping motor providing increments of motion corresponding to the incremental distance along the cam periphery; pivot shaft means mounted in said frame mechanism at a point spaced apart from said magnetic disk and substantially normal to the plane thereof; upper and lower pivot arms pivotally rotatable about said pivot shaft means and supported thereby, the free ends of said pivot arms extending adjacent said first and second cam disks respectively; head assemblies mounted on said pivot arms adjacent the free ends thereof and extending in cooperative relation with the upper and lower surfaces of said magnetic disk respectively; cam follower means rotatably mounted adjacent the free ends of said upper and lower pivot arms respectively and each engaging a different one of said planar disks; and a pair of spring means, each having one end engaging said housing means in fixed relation and the other end engaging a different one of said pivot arms and urging said pivot arms in a direction of rotation to maintain the cam followers thereon in engagement with the periphery of the associated cam disk.
Claim 32
Independent Claim
352 words
A system for supporting and maintaining a pair of magnetic head mechanisms in air-bearing relation to a rotating magnetic disk disposed in a given plane and comprising: a frame mechanism having upper and lower spaced apart portions for disposition adjacent a magnetic disk; a pair of planar cam disks disposed in planes substantially parallel to the magnetic disk and spaced apart proximate the frame mechanism between the upper and lower portions thereof, the cam disks each including a circumferential pattern of alternating dwell and transition portions, the dwell portions being at different radii from the axis of rotatioon of the disk in a progressive pattern, each radii defining a different track position on the magnetic disk; stepping motor means mounted on the upper portion of the frame mechanism and including a shaft extending between the upper and lower portions and engaged to drive said spaced apart cam disks, and including bearing means disposed in the lower portion of the frame mechanism for supporting the terminal portion of the stepping motor shaft, the stepping motor providing increments of motion corresponding to the incremental distance along the cam periphery; pivot shaft means mounted in said frame mechanism at a point spaced apart from said magnetic disk and substantially normal to the plane thereof; upper and lower pivot arms pivotally rotatable about said pivot shaft means and supported thereby, the free ends of said pivot arms extending adjacent said first and second cam disks respectively; head assemblies mounted on said pivot arms adjacent the free ends thereof and extending in cooperative relation with the upper and lower surfaces of said magnetic disk respectively; cam follower means rotatably mounted adjacent the free ends of said upper and lower pivot arms respectively and each engaging a different one of said planar disks; and a pair of spring means, each having one end engaging said housing means in fixed relation and the other end engaging a different one of said pivot arms and urging said pivot arms in a direction of rotation to maintain the cam followers thereon in engagement with the periphery of the associated cam disk.
Claim 33
Dependent Claim
43 words
The invention as set forth in claim 23 above, wherein said spring means urge said cam followers against said cam disks with a selected range of spring force through the extent of radial movement defined by the radial variations of said cam disks.
Claim 34
Dependent Claim
109 words
A disk file accessing system for advancing a magnetic head assembly to successive tracks of a record member comprising: head assembly mounting means capable of undergoing movement relative to the successive tracks of the record member; cam follower means coupled to the head assembly mounting means; rotatable cam means having an outer periphery in engagement with the cam follower means, the outer periphery comprising different segments having different radial distances from an axis of rotation of the cam means; means coupled to rotatably drive the cam means; and means for normally biasing the head assembly mounting means to maintain engagement of the cam follower means with the cam means.
Claim 35
Dependent Claim
109 words
A disk file accessing system for advancing a magnetic head assembly to successive tracks of a record member comprising: head assembly mounting means capable of undergoing movement relative to the successive tracks of the record member; cam follower means coupled to the head assembly mounting means; rotatable cam means having an outer periphery in engagement with the cam follower means, the outer periphery comprising different segments having different radial distances from an axis of rotation of the cam means; means coupled to rotatably drive the cam means; and means for normally biasing the head assembly mounting means to maintain engagement of the cam follower means with the cam means.
References Cited (Backward Citations)
US3314057A
Cited
US3681525A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |