This is a patent application entitled "SMALL ENVELOPE DISK DRIVE", Serial No. 07/612,204 filed November 13,1990

Refers-res cited:

4,794,586 11/1989 Korth 369/215

4,965,684 10/1990 Stefansky 360/78.12

4,890,176 11/1989 Casey 360/105

4,796,122 1/1989 Levy 360/98.01 4,796,131 1/1989 Chang 360/106

4,638,383 11/1988 Mc Ginlay 360/77

4,995,025 2/1991 Schulze 369/32

BACKGROUND OF THE INVENTION

The present invention relates primarily to flying head moving storage devices with either magnetic and/or optical head/slider meansV A large amount of disclosure relating ^to this invention particularly also regarding the pivot technology including inherent partial rotation yaw-axis means is referred to in patent #4,995,025 Schulze.

Besides a customary spindle, typically ball bearings are also used for linear and/or rotary pivot means suspending said flying heads and mover means like voice coil or magnet. Also being costly, these ball bearing pivots exhibit an undesirable amount of especially' non-repeatable friction and . ^' only a very low degree of

Ball bearing pivots require also tight tolerances for the interfacing parts. The seating, run-out and evenly distributed preload of the races are of great signifiance in order to assure proper servo-operation. A ball bearing by contrast to a single physical contact point of the invention has two contact points per ball of several balls being used. The employment of ball bearings also requires a certain amount of space and a pivot shaft. This shaft and portions of the voice coil mover means may be separate elements and are attached to a deck by screws, staking and/or other assembly means. In some other units,, portions of the pivot are an integral part of the deck and a cast-in or integrated part of the arm assembly including a shaft. The elimination of parts and reduction of assembly time besides improved functional characteristics would be desirable.

SUMMARY OF THE INVENTION The present invention has the potential to reduce dead-band for the pivot, eliminate the ball bearings as well as parts for the mover besides others and provide a certain amount of damping for the pivot interface. Furthermore, at least the ferro-magnetic or permeable portion of the magnetic loop and/or the pivot structure means besides other structural elements have the potential to be an integral portion and/or be integrated into the deck by means of stamping and/or coining or other operations. The pivot consists of two spaced apart pivots with inherently limited rotational range thus allowing such low cost approach. Also, the pivot assembly may be integrable and be of permeable material providing ample cross-section

at highest flux level for the magnetic loop besides allowing convenient pre-assembly.

The permeable portion is here an integral part of the pivot structure means. The media may be fixed and/or removable.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a top view of one embodiment of the present invention; Figure 2 shows a front sectional view of Figure 1 also showing two pins of spaced apart pivot means; Figure 3 shows a pivot configuration with perhaps plastic inserts for the cups; Figure 4 shows a pivot configuration without plastic cups, preload magnet pair and separation stop; Figure 5 is a side view of the deck pivot structure means; Figure 6 is a top view of the present invention employing a pivot with perhaps plastic insert also emphasizing the permeable loop being an integral portion of the deck; Figure 7 is a sectional side view of Figure 6; Figure 8 and Figure 9 emphasize compactness;

Figure 10 shows orthogonal mini-tracks superimposed on major track; Figure 11 shows additional tilt of mini-tracks; Figure 12 shows additional position references; Figure 13 shows one of many possible parcel configurations; Figure 14 shows interfacing of tracks;

Figure 15 shows sub-mini-tracks superimposed on mini-tracks Figure 16 shows permanent position means in center of

Figure 17 shows cluster and/or parcel;

Figure 18 shows a top view of the present invention showing cone and/or curve shaped voice coil configuration and curved movable magnets; Figure 19 is a cross-sectional side view of Figure 18 showing said voice coil interface with permeable loop elements; Figure 20 shows one potential pivot configuration with provision to accommodate vertical configuration like Figure 18;

Figure 21 shows two voice coils with only one force contributing leg; Figure 22 shows a permeable deck insert and housing ; Figure 23 is a cross-sectional side view of Figure 22; Figure 24 shows assembly on a wallet size card; Figure 25 shows a side view of Figure 24; Figure 26 shows a top view of the actuator including the magnetic loop and employing sheet-metal arm parts; Figure 27 shows a partial side view of Figure 26 also displaying dual pin pivot, voice coil and preload means for one disk; Figure 28 shows a side view similar to Figure 27 with two disks; Figure 29 shows a top view including cast, detachable arm parts;

Figure 30 shows in essence a side view of Figure 29 with a two disk arrangement; Figure 31 shows a cross-sectional side view highlighting cast arm parts for a two disk arrangement; Figure 32 shows a side view of a one part or integral casting for a two disk arrangement; Figure 33 shows a top view for arrangement of Figure 32; Figure 34 shows in essence a side view of Figure 33 displaying the voice coil;

Figure 35 shows a cross-sectional view of a multi-functional element including pivot structure, integrated voice coil, permeable loop and portion of preload means; Figure 36 shows a cross-sectional view including controllable bias and/or preload means for preload arrangement;

Figure 37 shows a side view of multi-functional element of Figure 35 displaying both cups and a pin means means for a preload arrangement; Figure 38 shows a cup implementation with partially elongated groove;

Figure 39 shows the outlines of a unit with about a 1.8 incn diameter disk which perhaps could be mounted on a wallet size card; Figure 40 and Figure 41 show side views of Figure 39 emphasizing a 10 milli-meter height;

Figure 42 shows an arrangement aiding static balance in the vertical direction for card mounting or similar; Figure 43 shows a movable voice coil and magnetic preload configuration; Figure 44 shows a preload configuration with magnetic loop closure structures; Figure 45 shows roll-off motion at pin/cup interface; Figure 46 shows an enlarged view with flat roll-off surface; Figure 47 shows an enlarged view with elevated roll-off surface;

Figure 48 shows an enlarged view with lowered, blended-in roll-off surface; Figure 49 shows a preload arrangement for vertical force exertion at the instant contact point/line; Figure 50 shows a sliding pivot arrangement; Figure 51 shows a side view of Figure 52; Figure 52 shows a vertical registration with an elongated pins arrangement; Figure 53 shows a spring preload arrangement;

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DESCRIPTION OF THE PREFERRED EMBODIMENT

Figure 1 shows an implementation of the present invention. There are essentially two pivot structure means. One is associated with a movable arm structure, another with the deck. The deck is a structure which typically accommodates the functional elements in order to form a spacial relationship and/or facilitate data storage and/or retrieval with media means, The deck pivot structure means 1 is a stamped and bent up portion of the deck, leaving an opening 2 in the deck. A cup 3, which may be of plastic material, is inserted into this deck pivot structure means.

The pins 4, which may have a nickel surface or employ stainless steel, are attached or are an integral portion of a stamped and bent down portion of the head/pivot/mover structure or arm structure/assembly.

The magnet 6 is a part of a preload implementation for the pivot and is attached or integrated to the deck pivot structure means.

The magnet 7 is attached to structure 5. The magnets repel each other so that cups 3 and pins 4 are pulled together. The gimbal mount 8 of structure 5 provides a mounting surface for gimbal 9 of head 10. The disk 11 is the media for data storage and/or retrieval interfacing with head 10. Figure 2 shows a sectional view of Figure 1. On deck 12 are also mounted a spindle with disk means 11, printed circuit board or equivalent 13 and perhaps a sealed cover 14.

Figure 3 shows the deck pivot structure means 1 with cup arrangement 3 inserted. The separation 15 may aid thermal matching requirements. The expansion/contraction is now generated or controlled by both pivot structure means and potential displacement at the interfacing contact

points and/or surfaces of the pin/cup assemblies are minimized. For the same reason and to accommodate for tolerances, the lower pin of pin arrangement 4 is shorter than the interfacing cup groove 16 of Figure 5 leaving clearance on both sides. The upper and lower pin/cup implementations may be reversed.

The optional elongation of pin 4 is for lowering of surface tension. The lower pin/cup together with the upper pin/cup contact points/lines/surfaces establishes an axis about which relative motion between the pin/cup structures describing inherently partial rotation may occur. The upper pin provides also vertical registration and its cup interface/surface/cone orientation can be favored by slanting. If more cup strength, as example, in the vertical registration direction is desired, the angle in reference to the cup center-line in this direction could be made smaller than in its operational orthogonal direction. The pin/cup configuration is substantially cone shaped which may include the, however, slight rounding of the pin-tip and/or cup groove, the perhaps oval, funnel, step, elongated and/or linear or similar cup shape of its ascending surfaces among others.

Certain applications, among them lightly loaded ones,may not require an actual cone shape and the pin/cup interface may consist of minute roundings only. The pin may consist of a cylinder with a rounded end and may also have a larger cross-section and may include ferro-magnetic material to interact with a magnet to exert preload. A rotatable, eccentric ring may adjust for bias. These and similar configurations shall be included in the term cone-shaped also.

The lower cup segment may be slightly floating. Though not limited thereto, the plastic material may be polyimide or ultra high molecular weight high density polyethylene

preferably with graphite inclusion and/or solid and/or viscous means for lubrication. The use of these high strength plastics will ensure a high amount of damping. This damping will help to isolate vibrations induced largely by spindle and/or mover to the flying head via structure 5. Instead o.f said flying head, a free end which does not fly may be used for certain applications including focused beam technology like in Optical Recording. The free end will then be in the vicinity of head 10. Free end shall also denote such head.

Figure 4 shows the deck pivot structure means 1 with a coined cups 17 arrangement, separation stop 18 and preload magnet arrangement 19, here attracting. In the context of this disclosure, attracting shall also mean repelling. One magnet may suffice. Favorable placement of arrangement 19 will reduce surface tensions.

Figure 5 is a side view of the deck pivot structure means 1. Groove 16 of the lower cup means shows an elongation. Figure 6 shows that a very compact unit is achievable. A conventional unit with perhaps a flat coil would require typically more length beyond the mandatory disk space while the pin/cup arrangement requires only a smaller envelope.

The permeable magnetic loop portion 20 is a stamped and bent up portion of deck 12. The deck rounding 21 completes the magnetic loop and both are an integral part of deck 12. No assembly and separate parts are required for the permeable loop. The bent up portions may require coining. The stationary voice coil 22 is attached or integrated to loop portion 20.

The moving magnets 23 are attached to a bent down portion 25, see also Figure 7, of structure 5. The printed circuit board or equivalent 24 may be mounted within the deck cavity. Figure 7 is a sectional side view of Figure 6 also showing

the interfacing of the elements emphasizing the magnetic loop elements.

It has to be noted that the number of disks is arbitrary. One disk is a possibility as well, for example. To provide additional gimbal mounts 8, structures similar to as shown in arm structure 5, may be assembled via spacer means.

The pin to cup interfaces and/or contact means are not limited to the beforementioned choice of materials and configuration. Surface augmentation and/or densification of plastics could be utilized. Ceramic materials adapted to suit the application may be used. The cups may be of metal and in certain instances be devised with isolation pads Porous phosphor bronze and external lubrication means may also find application.

The arrangement has some similarity to knife edge pivots, however, some trade-offs between friction and the induced dead-band and surface tension and possible wear has to be c nsidered.

It may also be feasible to either include magnetic material into the cups and use perhaps nickel coated iron or ferro¬ magnetic pins thus generating the preload. The pins may be integral or staked or similarly integrated into structure 5.

The mover means could employ conventional means including a flat configuration.

The stop means could be an integral portion or be integrable with the arm or the deck structures or both. It can be shown that reasonable dimensions for the particular components can be achieved while the drive could also accommodate disk dimensions on the perhaps lower end of the spectrum like 1.8 or 1.25 inch diameter or even smaller. Figure 8 and Figure 9 highlight approximately such a size reduction, but is not limited thereto.

Depending on level of integration, the printed circuit board or functional equivalent may also potentially be accommodated within the confines of the deck structure. Magnetic levitation will have no contact points, however, should be termed as such.

The openings in the deck may be covered with a pierce resistant material or tape.

The vertical bent up portions could be integrated into or be an integral portion of an insert which in turn may be integrated into a housing which may be of plastic and/or aluminum or other suitable materials for weight considerations. In a disk type environment, a maybe optical head might fly for focusing purposes. With a responsive beam means, only low surface speeds for high transfer speeds are required. On the other hand, higher transfer speeds at same surface speed may be realized. Particularly when surface emitting lasers or similar high response beam means become available, the beam could be directed back and forth in orthogonal direction in reference to the conventional or major track while retrieving and/or storing data and/or signals. This would establish lateral mini-tracks superimposed on a main or major track while allowing much lower surface speeds in order to transfer a comparable amount of data and/or signals.

In perspective, the effective surface speed is higher. The orthogonal direction may have a component in said track direction depending on speed relationships. The direction is ^■ "substantially" orthogonal covering also possibly tilt. The relatively low surface speed also establishes an almost vibrationless environment aiding servo operation thus enabling the utilization of extremely small features on the media.

Providing the beam deflection means or equivalent is capable thereof, perhaps transfer speeds approaching the "1 /e figure" of the particular technology could be achieved at very low surface speeds of the structure with the free end. The speed may ^De head and/or media technology limited. The responsive beam means has

a speed which is typically much higher than the speed of the free end, allowing quiet, low power and low vibration operation among others. A variety of bit arrangements and/or sequences can be devised. The beam may also be moved from "parcel to parcel" by the free end. A parcel is defined by a normally small confined area within the surface of the media, which could have a large variety of shapes, see also Figure 13. Clusters with simultaneous operation of several beams shall be included in the term "parcel", see also Figure 17. Figure 10 shows a strictly orthogonal configuration of bit cells of the concept whereby the beam speed moving along a mini-track is much higher than the speed of the free end 26 along a conventional or major track. Leading and/or lagging capability of the beam means may be required, if no start/stop operation is used.

Figure 11 shows an arrangement whereby perhaps a slight divergence of tracks occurs which may be due to speed relationships and/or capabilities of the beam means, perhaps being uni-directional among them, and structure with free end mover. The arrangement could be expanded by superimposing again orthogonal perhaps

"sub-mini" tracks 30 on the substantially orthogonal mini tracks and again being sustantially in line with the- major track movement, see also Figure 15. This same configuration may also find application for perhaps optical tapes where the tape is guided into a curve which may be a partial sphere. Nutating movements of a free end are substantially orthogonal to tape motion while again orthogonal movement of perhaps a beam is superimposed on a movement of a free end. The bit cell arrangement could be expanded again. Similar conditions may exist for printers/ scanners. Depending on particularly the range and/or tilt tolerance of the beam deflection means, spaced apart pivot means may suffice. Perhaps a substantially round folded paper, which may¬ be "Digital Paper", is guided past a free end. A very compact configuration can be devised.

Figure 12 shows an arrangement similar to Figure 11, however, the areas previously left blank by said divergence of tracks have now permanent position references which may have a variety of configurations, see also Figure 13, for continuity m a "parcel by parcel" type arrangement could be utilized. The direction of a beam movement of a mini-track and/or parcel can be in any direction, perhaps partly also in the direction of the major track, The term "of substantially different direction" shall avoid an interpretation that a mini-track be located right on top of a major track as well as to include that a mini-track may cross a major track.

Figure 14 shows interlacing of mini-tracks 27. A bit cell track may aid the accessing of tracks.

In general, a high response beam means with preferably no physical movement of structure, but only perhaps electro-magnetic waves such as light emanating from a much slower free end moving along a perhaps major track realizes more data bit cells and/or signals than it otherwise would. The beam speed is typically much higher than the speed of the free end. For lower transfer-rates lower response beam means may, however, suffice. Other means than electro-magnetic waves are a possibility.

Besides data the term "signal" was chosen to among others also denote analog storage/retrieval, which may be done by optical means. Tracks are the bit paths along which data and/or signals are being stored/retrieved. For a top view of the media surface, these paths are typically round for disk type devices. For tapes they are usually linear along the tape, except for helical scan where they are substantially tilted in reference to the tapes center-line. A spherical pivoting actuator may typically also have linear tracks for the movement of the major track. However, other shapes including sine-wave, trapezoidal,zig-zag and others are possible. The ratio of the amount of the stored and/or retrieved data and/or signals to the data along the movement of the free end or major track may be proportional to their surface speeds.

The major track motion in this application may not have a contiguous data stream. The term track here may refer substantially to the motion only, but need not to. The ratio is also dependent on the deployment of tilt and/or permanent position and/or timing references. The surface speed for data/signal exchange may be slow, while higher speed could be used for accessing. Parallel beams could be used also.

Figure 18 shows another implementation particularly for the mover means. The magnets 27 are curved in order to achieve a shorter air gap for higher efficiency of the magnetic loop. The permeable bent up portion 26 interfacing with the voice-coil 28 is substantially cone shaped, also in order to shorten the air gaps. The voice-coil, either fixed or removable, is shaped in order to accommodate the shapes for the interfacing elements as yoke and magnet. Particularly the interfacing surfaces may be straight and/or curved. The magnetic flux interfacing with the coil legs does not close about its center like in Figure 6. The closure of flux through the center of the bent up portion would provide a shorter and more efficient flux path and essentially no flux would pass through the flat portion of the deck providing no saturation occurs, however, an added element could provide for flow of flux through the center. In certain configurations, such center part may be established by a single bent up portion. The pivot structure means 1 and permeable loop means 20 of Figure 6 could be combined into one part which may be an integral portion of the deck or be integrated into the deck. Instead of sheet-metal, such structure or element may also be a solid,shaft-like element and perhaps also integrable. The outer permeable loop element or yoke 21 , could be included forming an insert which could also be expanded to include at least an integral portion and/or assembly interface means for the spindle and besides sheet-metal, powder-metallurgy with ferro-magnetic material may be used. The choice for any particular application may depend on structural and other considerations. The magnets have also different polarities as before.

Figure 19 is a side view of Figure 18 and shows the coil interface 29 with protruding permeable loop element to achieve a compact and efficient configuration. The pins 30 and 31 should be as far apart as possible n order to attain a favorable aspect ratio with the free ends and better stiffness.

Figure 20 shows one possible pivot assembly implementation. The upper pivot 37 can be temporarily recessed by screw action in order to allow a fixed pin arrangement. In integrated or integrable deck pivot structure means configurations, the movable magnets or voice coil may be attached last enabling a fixed pin/cup configuration. Particularly for shallow cups, the air gap of the magnetic loop may provide adequate assembly clearance, a dead stop is to be added to prevent separation of cup and pin. The magnet 35 provides a preload to the pivot arrangement. The interfacing portion of the deck pivot structure means 39 is rounded so that an equal distance to the magnet is maintained. This assures an equal force over the operating range. A second magnet with the same interfacing shape could be used for higher force exertion. The dead stop 36 also interfaces with such a rounded shape of the arm pivot structure means 38 and assures that no permanent separation of pin to cup occurs when high shock is imparted on the unit. Also shown are upper cup 33 and housing means 40. _ -

Figure 21 shows another version of the mover means. There are two voice coils 32, but only one leg per coil contributes to force generation. Perhaps operating with only one coil or two in differential or similar mode for tracking may shorten rise times for improved response.

Figure 22 shows a permeable insert 41 into housing 48, which material may be aluminum, plastic and/or other suitable means. The opening 42 is for the assembly of a spindle motor. A configuration may be devised which also utilizes insert 41 as a functional part of the spindle motor by means of a drawn up ring or similar, thus reducing motor cost and/or tolerance build-up. The openings 43 are created by bent up pivot structure means 44 and permeable loop

element 45. The deep drawn portion 46 closes the magnetic loop and interfaces with fixed or movable magnets. The drawn up portion 47 is only shown as the shape when the entire bowl or deck including part of the probable housing is also of permeable material including steel sheet metal. The housing may essentially interface either on the top or the bottom as shown. The insert/housing or or portions thereof may also perhaps be devised by powder- metallurgy with ferro-magnetic material, with permeable loop 45 and pivot structure 44 being one integral or integrable part or element, Figure 23 is a side view of Figure 22 also showing the insert and potential housing.

Figure 24 shows a miniaturized size version mounted on a credit or wallet size card, however, the unit is not limited to such particular size. The electronics and/or similar elements may be placed on such a card means which may include printed circuit means. Figure 25 is a side view of Figure 24.

Figure 26 shows an implementation whereby the pivot/yoke structure 50 may be integrable, i.e. attachable/detachable/permanently affixable to/from the deck and/or insert, but also provides for a permeable portion 51 of the magnetic loop for the voice coil arrangement. The voice coil 52, two pivot cups and a preload interface, perhaps a pin, are also mounted on said multi¬ functional element 50, which may lend itself for powder metallurgy manufacture. This element can also be permanently affixed to either deck or cover of housing means by means including staking, loctiting and the like. The pivot cup could be precision molded into this element, or permanently attached whereby the cups are backed against a precision assembly tool by means including springs. Also shown is a flux path 53, whose direction 54 could also be reversed, which may be very efficient indicated by the shortness of the average flux line. A relatively large cross- section may also be provided. Since perhaps the epoxy coated magnets 55 to voice coil

distance or air gap 56 may typically be smaller than tne pin from cup separation distance 57, no separate dead stop may be needed especially for smaller units. Figure 27 is a side view of Figure 26 showing the pins 58, cups 59, preload arrangement 60 and sheet-metal arms 61, which may perhaps be essentially flat substrates of aluminum, stainless steel, plastic or other suitable materials. In case thin sheet-metal gages are used, the sheet-metal substrates could be reinforced by projections or other reinforcement means. The gimbal and arm extension may be integral. The pins could be integrated or be an integral portion of a pivot arm assembly structure. Figure 28 shows a similar arrangement with two disks 62 instead of one. Figure 29 shows a top view with integrable cast arm parts.

Figure 30 is in essence a side view of Figure 29 showing the interfacing and assembly of the cast arm parts with the unit. Figure 31 shows a cross-sectional side view of exclusively the cast arm parts, heads, disks and housing. It has to be noted that the upper and/or lower arm may be of flat substrates also, but are not limited thereto. Figure 32 shows a side view with a cast integral arm arrangement 63, heads, disks and housing.

Figure 33 shows a top view also for an integral arm arrangement of Figure 32.

Due to its relatively large cross-section perhaps extending into the flat portion of the deck and/or insert, the permeable portion 64 may be possibly of relatively thin sheet stock. Integrable and/or integral structure and/or elements and/or combinations thereof may include, but not limited thereto, means for pivot like pin and/or cup and/or interface structures; permeable magnetic loop; voice coil mounting structure/interface means, preload; mover like voice coil/ magnet, permeable loop portion; deck and/or insert like structure accommodating including tying and/or providing

other structure and/or elements in a spacial relationship like permeable loop means, spindle/interface or portions thereof, pivot structure means, interfaces/structures like covers, head-load/unload ramps, filter, shocks, parking-latch, head-lifter, baffles, mounting brackets, reinforcements, outlets (servo, cable, vents, filter etc.), stops and housing among them.

The terms structure or element are not mutually exclusive. Although the primary emphasis is focused on the pin/cup pivot invention, it should be noted, however, that several integrable and/or integral structural and/or functional elements can also find application with conventional ball bearing or similar pivot means and mover means. Included, but not limited thereto, may be deck/yoke, portion or yoke means in combination with integral element,stops, at least pivot portion, spindle/interface/ plane sheet-metal excluded. More specifically, a multi-functional element either as insert or housing with conventional pivot means and permeable powder-metallurgy may include the pivot housing or tube-like extension into which the bearings are assembled (while the shaft is in the arm structure), which may also serve double duty as inner yoke portion, the outer yoke, (may be single part also) a spindle ring either upright or flat (either functional with spindle or for mounting purpose), extension into a bowl like housing, stops, eyelets and possibly elements as mentioned before. For certain applications, these elements could also be implemented with a sheet-metal version.

It is pointed out, that particularly a preassembly of perhaps arms, pivot, preload, voice coil and magnets lends itself for convenient cleaning including ultra-sonic bath before the sensitive heads get attached. However, cleaning with heads/ cable attached may be a possibility.

A relative advantage of the abovementioned assembly is its insensitivity and/or ruggedness allowing assembly outside of clean rooms and providing for easy shipment and handling. The pin/cup interfaces are shock-proof by comparison and no brinelling of balls to races as in ordinary ball bearings conventionally used will occur if laid out properly. The reason that the pivots could be devised in these configurations is the low inherent operating range, which may be in the order of 20 to 30 degrees or so, but is not exactly limited thereto.

In contrast, pivots using ball bearing means could be rotated full turn if no stops were used as well as partial turn. Their inherent design is not for partial turn or rotation only. However, since only partial turn movement is required, the full turn capability being much costlier is abundant and perhaps wasteful, which is one of the distinctions.

Figure 34 shows a side view including the voice coil mounted to a multi-functional element.

Figure 35 shows a cross-section perhaps near the center of the multi-functional element accommodating at least pivot, yoke, coil mounting structures and preload functions, displaying the voice coils active legs 65, a pivot preload arrangement with a permeable pin means 66 assembled and/or integral, magnet 67 and permeable adjustment plate 68. Basically either by way of tolerance stack-up and/or adjustment including shimming, an air gap 69 will be maintained within limits to assure a proper preload range. However, the effective force direction of the magnet should ideally go through the axis formed by the two pivot centers in order to achieve a zero bias torque. An excessive bias torque means additional unwanted power dissipation for the servo-drive.

Since besides conventional tolerances the flux distribution of a magnet can also vary, a permeable adjustment plate may be fixed to the movable arm arrangement and allows the sideways sliding of the magnet to essentially eliminate the bias torque.

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The magnet means may also be pretested and precision means be provided for assembly. In movable magnet configurations for tne voice coil mover, the attraction of tne magnets to the permeable αeck/msert means may also provide pivot preload means due to a snorter air gap. Bias balance or the elimination of bias can De accomplished by either magnet alignment or addition of slugs or equivalents which may be magnetic.

Figure 36 shows a controllable bias means including adjustment plate, magnet 72, distribution element 70 and coils 71 preferably arranged symmetrically about the force direction of the assembly. The distribution element may provide more evenness for the flux lines but may be optional. The rounded extensions provide higher efficiency but may also be optional, see Figure 35. The coils 71 could either individually, differentially or in tandem shift the aggregate center of the flux thus controlling effectively the bias torque. They could also provide preload depending on size. However, the bias torque is typically low.

As said, the servo could compensate for the bias torque, however, under certain conditions, it may prove favorable for the operation of the servo to have as low a bias torque as possible to achieve highest precision and response. One of the coils may suffice. Figure 37 shows a side view displaying essentially the pivot cups 73/74. As shown, the cup 73 indentation has an oval shape favoring strength in the direction of the pivot arrangements axis. This may optionally be devised since cup 74 provides only frictional force in this direction. The cup 74 has an elongated groove.

If the cups are affixed or integrated to the pivot structure means so that the cup mounting surface lines up with its pm/cup contact area thus effectively neutralizing the typically higher coefficient of thermal expansion of the cup, any thermal variations will essentially not originate from the cups. The spacial relationship of the pin/cup configuration will

substantially stay within the confines of micro-inches. This will include the minute thermal variations, roll-off of pin/cup, potential sliding movement between pm/cup, minute potential diplace ents generated by damping, the control/prevention of movement along the axis and other associated phenomena. It will also include the rotatable prevention means against movement along the axis formed by the two contact points/lines/surfaces which may require at least one further contacting surface. Figure 38 is similar to cup 73, however, an elongated groove of limited length was added. The elongation of the groove is devised to compensate for tolerances and assure definite, repeatable position. For control of motion along the axis,press-fitting may¬ be required.

Figure 39 shows about a 1.8 inch diameter disk type version potentially to be mounted on a card, but not limited thereto nor to its size.

Figure 40 and Figure 41 show a height of 10 illi-meter. Figure 42 shows a concept and a modified version whereby the effects of gravity in the mounting position as shown are largely minimized.

Additional provisions may be required also depending on number of disks/heads employed.

Figure 43 shows a configuration with a movable voice coil 76 and with the stationary magnet attached to the deck or permeable deck insert. A thin glue line assures a short gap 75 or perhaps essentially no gap. The voice coil leg or portion 77 may be rounded allowing vertical mounting with the shaft-like multi¬ functional element.

The magnet insert 78 is coated with wear resistant means interfacing with the pin which may be of permeable or ferrous nickel coated or similar material and providing more bulk 79 to serve the preload function.

A rotatable, integrable, eccentric ring or clamp arranged about the center may correct for bias, as well as similar implementations-

Figure 44 shows a preload arrangement whereby a magnet 81 and permeable or soft iron loop closure structures 82 provide high efficiency. The arrangement interfaces with a version of a permeable multi-functional element 80 which is here recessed. Also shown are magnetic flux pathes 83, a bias/preload adjustment clearance 84, pivot 85 and movable arm structure 86. Essentially, the preload will not introduce a bias or bias changes dependent on angular position of arms structure 86. Figure 45 shows a pivot with roll-off motion for lower friction. The operating range is about 26 degrees, but not limited thereto. A pin-tip 87 is rounded with radius 88 while the centers of rotation 89 are shown in enlarged views of Figure 46, Figure 47 and Figure 48. Roll-off surface 90 with rotation centers 91 is flat, surface 92 is elevated and surface 93 is a blended-in curve providing a smooth transition with the outer surfaces.

Figure 49 shows a preload arrangement facilitating a direction and/or highest magnitude force normal or vertical to the instant contacting surfaces eliminating side components in order to control tangential offset of the Read/Write gap of the head. Figure 50 shows a pivot with sliding motion of surfaces 99 and the center of rotation is at the center of the pin-tip. Lubrication reservoir 100 may be extended into 101 for a larger supply of lubrication means. Figure 51 is a top view of Figure 52. Figure 52 shows a vertical registration means with an elongated pins arrangement.

Figure 53 shows a preload arrangement with spring means, of which a multitude of configurations could be devised.