Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
  • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following

Definitions

• This invention relates generally to magnetic recording apparatus, and more specifically to an improved support structure for electro-magnetic transducers of a type particularly usable with a magnetic disk data storage system, for transferring data between the transducer and a flexible magnetic disk.
• Background of Prior Art Requisite to all magnetic data storage systems are a magnetic data recording media for storing data in magnetic form and an electro-magnetic transducer having one or more "heads" for performing "reading” and/or "writing” of data in magnetic form, respectively from or onto the recording media.
• the "floppy disk” media is a thin, generally planar flexible or pli: ⁇ nt magnetic disk having magnetically sensitive surfaces and currently rotatable at speeds of approximately 360 r.p.m., within a protective envelope or jacket cover. Data transfer to and from the floppy disk is achieved by one or more electro-magnetic heads arranged within, and collectively forming a transducer. The transducer (or transducers) communicate with one or both surfaces of the floppy disk through window openings in the protective envelope.
• transducer structures useful for communicating with floppy disks have appeared in the prior art. In general, those portions of such transducers that are responsible for the electro-magnetic transfer of data to and from the floppy disk,- have not significantly differed from one another in their basic component pieces.
• Each such transducer basically comprises a plurality of magnetic core members prepositioned with respect to one another, secured together and interconnected with one or more coils, to define an operable electro-magnetic transducer.
• transducer structures as used in association with data transfer to and from a floppy disk, have comprised a single channel read/write head, and may typically also include an erasure head.
• the erasure head generally comprises a plurality of erase cores for trimming a "track" of information written onto the floppy disk surface, and for erasing a pair of guard-band areas on each side of the trimmed track.
• the particular structural details and relative placement of the electro-magnetic components which collectively comprise the various head portions of an electro-magnetic transducer are not important per se, since this invention applies equally well to any electro-magnetically operative "type" of such transducer and component head structures thereof, whether they are multiple or single, erase, read, write or combination read/write heads.
• the present invention applies equally well to both "single-sided” and to "double-sided" floppy disk data transfer systems.
• Floppy disk systems of the prior art both single and double-sided, have typically mounted their respective transducer “assemblies" upon a movable carriage structure which is radially indexed with respect to a relatively fixed-position floppy disk. Movement of the carriage structure enables the transducer or transducers carried thereby to access different desired circumferential "tracks" on the magnetizable surface (s) of the floppy disk.
• C.R.P. Customer Reference Plane
• Nominal Disk Plane will be defined as that plane in which a surface of a floppy disk nominally lies during operative rotation of the disk. Since a floppy di K has two data transfer surfaces that are separated by the thickness of the floppy disk, it will have two Nominal Disk Planes, generally referred to as "upper” and “lower” Nominal Disk Planes.
• Nominal Disk Plane In a single-sided floppy disk system, only one Nominal Disk Plane will be of concern for data transfer operations since data is transferred to only one side of the disk at a time. In a double-sided floppy disk system, wherein data transfer is simultaneously possible to both sides of the disk, both the upper and lower Nominal Disk Planes are of concern. Normally, the Nominal Disk Plane lies in a plane parallel to and spaced from the C.R.P.
• the two data transfer surfaces of the floppy disk lie perfectly planar respectively in the upper and lower Nominal Disk Planes, with no imperfection therein such as wobble, or deformation caused for example by imperfections in the disk itself, by the flexible natur of the disk or by motion transmitted to the disk by the apparatus rotating the disk.
• Prior art floppy disk data transfer systems have differed in their designs of the transducer support structures that are mounted to the movable carriage.
• the transducer In early single-sided floppy disk systems, the transducer generally had a curved surface for operatively engaging the floppy disk and for penetrating into and beyond the Nominal Disk Plane of the engaged data transfer surface.
• the transducer was generally fixedly mounted to the movable carriage.
• a hinged arm carrying a pressure pad was pivotally mounted to the carriage to allow for disk entry. The arm was spring-loaded, such that the pressure pad carried thereby engaged the disk at a location directly opposite the transducer head, and applied a known force to the disk, conforming the pliant disk into intimate engagement with the curved transducer head.
• the upper and lower recording surface areas of the floppy disk may periodically move out of their respective upper and lower Nominal Disk Planes.
• Such deviations could, for example, be caused by distorted disks or excessive disk wobble (i.e. perturbations in the disk surfaces as the disk rotates).
• various transducer mounting arrangements have been devised in the prior art, to accommodate such deviations in floppy disk operative movement.
• One such mounting configuration illustrated in U.S. Patent Re 29,380 reissued August 30, 1977, illustrates a method of mounting a pair of transducer slider heads in opposing relationship upon a pair of fixed support arms, movable under solenoid action, toward and away from one another for disk loading operations.
• the support arms engage stop members on a carriage, to limit the closure distance therebetween to a fixed predetermined amount.
• the opposing transducer heads are urged into forceful engagement with the disk by a pair of coil springs underlying the transducer heads, to sandwich the floppy disk therebetween.
• Such a structure has generally not provided the sensitivity in movement required for the transducer heads, to follow deviations of the floppy disk out of the Nominal Disk Planes during steady state operation.
• Such structure is also ⁇ usceptable to introducing data transfer errors caused by "shifting" of the transducer head surfaces relative to the recording tracks of the disk, when the transducer heads "tip" to accommodate perturbations in disk movement from the Nominal Disk Planes.
• the structure exhibits a slow damping response following a loading operation (i.e. the process of engaging the opposing transducers to the rote ing disk). With this structure, intimacy of contact between the transducer heads and the recording surfaces of the floppy disk is reduced.
• the pivoted transducer support arms are interlocked such that motion of one such arm tending to raise one of the transducers from engagement with the surface of the disk, also moves the second arm so as to move the second transducer from the opposing surface of the disk, for loading and unloading the disk into and out of operative position.
• Each arm is urged with a predetermined force against its corresponding side of the disk, tending to maintain intimate contact between the transducer carried by that arm and its respectively engaged disk surface.
• the composite structure sandwiches the floppy disk between the opposed transducers at a relatively weak loading force of six to seven grams, which tends to give rise to instability.
• the double-gimballed structure is configured to enable rapid responsive movement of the transducer heads to accommodate perturbations in disk movement out of the Nominal Disk Planes
• transducer tracking movements give rise to shifting or offset errors.
• the transducer head moves on the universal girnbal structure to follow a disk surface that has left the Nominal Disk Plane
• the relative surfaces of the transducer head and the corresponding disk track being monitored thereby laterally "shift" relative to one another such that the read/write gap of the transducer head may be mis positioned with respect to the indexed recording track on the disk surface, thus reducing or impairing its data transfer with the trade.
• the direction of such sMft depends upon the direction of perturbation movement of the disk.
• Such shifting can be: in a tangential direction with respect to the recording track, giving rise mispositioning of the read/write gap with respect to bit location of data in the recording track; in a radial direction with respect to the recording track, giving rise to radial mispositioning of the read/write gap with respect to the physical location of the recording track on the disk surface; or in the direction of some compound angle lying therebetween.
• Transducer/recording track misalignment errors are also introduced through the universal movement of the dual gimbal structure, by any twisting or rotational movement of the transducer heads about an axis lying perpendicular to the Nominal Disk Plane and by any lateral friction-induced "shifting" of the transducer head surfaces in the Nominal Disk Plane itself.
• This structure is configured to improve the intimacy of contact between the transducer disk surfaces and to reduce some of the disadvantages of the prior doublegimbal transducer support structure.
• This structure uses an asymmetrical transducer support structure having a first or lower transdxicer with a planar transducer core surface that is .immovably fixed (as in early single-sided data transfer systems).
• a second (upper) transducer is mounted on a universally movable gimbal structure and is pivotally movable by a spring-loaded arm into operative proximity with the fixed lower transducer head so as to sandwich the floppy disk therebetween at a predetermined force.
• the lower transducer head structure is sized (in surface area) relatively larger than the upper transducer head, so as to extend considerably beyond the outline dimensions of the upper
• the core surface of the lower transducer is mounted so as to penetrate excessively into the Nominal Disk Plane of a loaded floppy disk, and the upper transducer carried by the gimballed support structure acts as a pressure pad for the lower fixed transducer head. Conversely, the lower fixed transducer head acts as a pressure pad for the upper transducer core. While reducing, some of the shifting and offset tracking errors inherent in the double-gimbal structure, this structure still experiences some mispositioning of the transducer relative to the recording track of the lower surface of the floppy disk, due to the fixed nature of the lower transducer head.
• the present invention overcomes most of the above-mentioned shortcomings of prior art transducer support structures, and is suitable for use in either single or double-sided data transfer in floppy disk systems.
• the present invention provides a transducer support structure that minimizes physical wear on the floppy disk, particularly during "loading" of a system.
• the present invention improves intimacy of contact between the transducer (s) and both disk surfaces during steady-state operation, thus improving data transfer and reducing drop-outs as a result of improved intimacy of contact, particularly where data transfer is being performed at higher transfer rates.
• the present invention realizes such improved results primarily by use of a support structure for a transducer which enables limited freedom of movement of that transducer head in a direction perpendicular to the C.R.P., while maintaining the transducer head's surface substantially parallel to the C.R.P.
• Such structure provides a significantly improved damping effect during a loading operation, reduces the settling time to equilibrium and provides good intimacy of contact between the transducer and the disk (and between both transducers and the disk in double-sided systems) which permits accurate transfer of data even before "physical" post-loading equilibrium has been achieved.
• the structure of this invention minimizes tracking errors due to lateral transducer/disk shifts when the transducer follows a disk surface that deviates from its Nominal Disk Plane.
• the structure of this invention also prevents tracking errors caused by friction-induced lateral shifts of the transducer head surface in the Nominal Disk Plane.
• the structure of this invention further prevents tracking errors due to rotational movement of the transducer head surface in the Nominal Disk Plane and about an axis perpendicular to the C.R.P. Summary of the Invention
• the present invention comprises a novel support structure for a magnetic transducer head assembly that is particularly suitable for use in data transfer systems of the type using non-rigid planar rotating magnetic recording media, such as but not necessarily limited to the floppy disk magnetic recording media.
• the invention applies not only to the novel Z Axis Flexure Support structure itself, but also to its operative application in combination with a second, oppositely opposed supported transducer or pressure-pad in double-sided and single-sided magnetic data transfer systems respectively.
• the invention also applies to a novel head assembly for magnetic recording structures having oppositely opposed supported slider members, wherein both slider members are mounted for independent movement but in a manner such that the slider members exhibit differential movement compliance with respect to one another .
• a magnetic transducer head assembly incorporating this invention includes a transducer having a data transfer surface suitable for slidably engaging a surface of a planar rotating non-rigid magnetic recording media, and a transducer support structure supporting the transducer for movement in a particular manner.
• the transducer support structure is configured to support the transducer for resilient movement in a Z-axis direction, while substantially preventing movement of the general plane of the data transfer face of the support transducer, in any directions not in the Z-axis direction.
• the transducer support structure therefore, substantially prevents movement of the transducer that would impart any deleterious lateral "shifting" motion to the data transfer surface that would give rise to data transfer errors.
• Such lateral "shifting" errors include both those shifts of the transducer face representing a component in the nominal X-Y plane, of the displacement due to the rotational motion of the transducer core about the X or- Y axis coordinates (described hereinafter in more detail), as well as friction-induced lateral shifts resulting from sliding frictional engagement between the recording media surface and the transducer data transfer surface.
• the transducer support structure permits a very limited amount of rotational movement of the supported transducer data transfer surface about the X and Y axis coordinates, to enable the transducer data transfer face to "follow" perturbations in operative steady-state movement of the recording media; however, such permitted rotational motions are so limited as not to give rise to data transfer shifting errors.
• the transducer support structure also substantially prevents shifts or movement of the data transfer surface of the support transducer in the X-Y plane, caused by rotational motion of the transducer about a Z-axis coordinate.
• the operative result of the transducer support structure is that the general plane of the transducer data transfer surface moves in a plane perpendicular to the Z-axis direction, with no data transfer error-causing lateral or rotational shJ ft of the data transfer surface even within its general plane.
• the Z axis when defined with respect to the transducer support structure, is defined as an axis lying perpendicular to the general plane of the data transfer surface of the transducer being supported thereby, when the transducer is mounted to the support structure with no external forces being applied to the transducer.
• the transducer support structure of this invention preferably comprises a housing suitable for engagement to a support surface, such as to a movable carriage of a floppy disk data transfer system; and a flexure support means mounted to the housing for supportingly carrying the transducer in the above described manner for resilient movement substantially only in the Z-axis direction.
• the flexure support means comprises a transducer mounting, member to which the transducer is fixedly mounted, and resilient flexure means extending from the transducer mounting member and secured to the housing for resiliently supporting the transducer mounting member for movement substantially only in the Z-axis direction.
• the shape of the data transfer surface of the supported transducer could be planar, spherical, or any other appropriate configuration, and that this invention applies equally well to all such configurations.
• the resilient flexure means may be of any configuration which operably combines with the transducer mounting member to provide the desired Z-axis direction support function.
• such flexure means comprises a plurality of leaf-like flexure axis members extending between the periphery of the transducer mounting member and the housing, whereby the transducer mounting member is suspended by and between the flexure axis members.
• the flexure axis members suspend the transducer mounting member, and the transducer mounted thereto within the central portion of the housing such that the data transfer surface of the transducer extends in the Z-axis direction slightly above the general plane of the upper portion of the housing.
• the flexure support means when including a plurality of flexure axis members , may have any number of such flexure axis members, which can be configured in any shape and form so as to accomplish the desired Z-axis support motion for the transducer.
• the flexure axis members are cooperatively configured with a resiliency sufficient to stably support the transducer both during transient loading operations and during steady-state operations, as determined by the particular data transfer system in which the transducer support structure is to be incorporated.
• a rather stiff flexure resiliency is preferred for reducing the physical settling time to equilibrium, while providing effective shock absorption properties for impact forces applied to the transducer during transient loading operations.
• the flexure resilience is designed for a balance between: the desired stiffness for transient loading operations; some elasticity in the Z-axis direction for absorbing Z-axis direction forces imparted to the transducer by perturbations in movement of the engaged data transfer media during steady-state operation; and allowance for minimal limited rotational deflection about the X and Y axis coordinates so that the data transfer face of a supported transducer has a tendency to respond to perturbations in movement of an engaged rotating recording media out of its nominal plane of rotation.
• the flexure axis members have width dimensions substantially larger than their thickness dimensions, and are curved in arc-shaped manner in the direction of travel from the transducer mounting member toward those ends of the flexure axis members which are secured to the housing.
• the arc-shaped flexure axis members suspend the transducer mounting member in a plane spaced in the Z-axis direction from the general plane of the ends of the flexure axis members which are secured to the housing.
• the plurality of flexure axis members extend outwardly from the transducer mounting member in catilevered manner, and have their outwardly projecting ends secured within a relatively rigid pexdpheral support frame.
• the peripheral support frame is secured to the housing by appropriate means such as by insert molding techniques or by direct bonding to seat areas pre-formed within the housing material.
• the transducer support structure of this invention may be used to support either the first or the second slider members which operatively engage opposing surfaces of a non-rigid planar rotating magnetic recording media.
• One of such slider members comprises a magnetic transducer capable of data transfer through its data transfer surface to the corresponding recording surface of the recording media.
• the invention comprises:
• first and second slider members each having at least one surface suitable for slidable engaging the planar recording surfaces of the rotating non-rigid magnetic recording media, at least one of the slider members comprising a magnetic transducer capable of data transfer through its said one surface to the corresponding recording surface of the recording media;
• positioning means for supporting the mounting means and slider members in generally opposing manner such that said one surfaces of the slider members operatively engage the opposite recording surfaces of the recording media; and (d) means operatively connected with the positioning means for urging the slider members toward one another with a fixed predetermined force, operatively sandwiching the rotating recording media between said one surfaces of the opposed slider members.
• the mounting means comprises a first mounting structure operatively carrying the first slider member in manner whereby said one surface of the first slider member is substantially constrained from move at in directions except for in a Z-axis direction that is normal to the nominal plane of the engaged recording media surface.
• the first mounting structure does allow for minimal limited rotational motion of the first slider member about the X and Y axis coordinates.
• the first mounting structure resiliently allows for such movement in the Z-axis direction such that the general plane of said one surface of the first slider member remains substantially parallel to the general plane of the recording media surface during movement of said one surface in the Z-axis direction.
• the differential relative movement compliance betxveen the surfaces of the first and second slider members engaging the magnetic recording media reduces wear on the engaged surfaces of the recording media, particularly during transient loading operations, by reducing the effects of the otherwise "hard” impact engagement of the first and second slider heads with the recording media surface during a loading operation.
• the differential relative movement compliance is achieved in a preferred structure by use of the above described Z-axis flexure support assembly for one of the opposed slider members and by use of a gimbal mounting structure for the second slider member, wherein the gimbal mounting structure permits universal movement of the engaging surface of the second slider member about a fixed pivot point, but prevents movement of that one surface in the Z-axis direction at the fixed pivot point.
• the positioning means includes at least one pivotally movable support arm for moving at least one of the first and second slider members relative to the other slider member such that the two slider members cooperatively move toward and away from opposing sandwiching engagement with the recording media for loading and unloading operations respectively.
• the invention comprises:
• a first transducer having a generally planar data transfer face and suitable for transferring data in magnetic form to a first side of a non-rigid planar magnetic recording media
• first mounting means for mounting said first transducer in data transfer position relative to the first side of said recording media, in a manner such that movement of said first transducer relative to said mounting means is substantially prevented in all directions except for in a Z-axis direction normal to the general plane of said media, despite movement of said transducer and mounting means to different positions along the general plane of the media;
• second mounting means for mounting said second transducer in data transfer position relative to the second side of said recording media, in a manner such that said second transducer data transfer face is relatively free to move in gimballed manner about a pivot point fixed with respect to said second mounting means, but wherein movement of said face is prevented in the Z-axis direction at the pivot point;
• support means operatively supporting said first and said second mounting means in generally opposed manner relative to said recording media, such that said first and said second transducer data transfer faces slidably engage in opposing manner the first and second recording surfaces of said recording media, sandwiching said recording media therebetween;
• the first transducer mounting means includes means for resiliently supporting the first transducer for movement in the Z-axis direction and for allowing minimal limited rotational motion of the first transducer about X and Y axis coordinates to allow the first transducer data transfer surface to follow perturbations in movement of the magnetic recording media surface, out of its nominal operative plane.
• the X and Y axis coordinates are orthogonally disposed to a Z axis coordinate passing through the geometrical center of the data transfer surface of the first transducer. It will be understood that the principles of this invention apply to the support of transducers having any shape of smooth, sliding data transfer surfaces, whether such surfaces be planar, spherical, or of another, configuration.
• Figure 1 is a perspective view, partially broken away, of a multiple transducer head and support apparatus incorporating the present invention, illustrated as mounted on a movable carriage such as used in a transducer system that communicates with both sides of a flexible media, wherein the accessing mechanism and associated parts of the system have been omitted for simplicity;
• Figure 2 is an enlarged fractional side view of a portion of the transducer system apparatus disclosed in Fig. 1;
• Figure 3 is :an enlarged perspective view of the lower transducer assembly of the apparatus disclosed in Figs. 1 and 2, as generally viewed from above, illustrating mounting of the lower transducer within the lower transducer assembly;
• Figure 4 is an enlarged perspective view of the lower transducer assembly disclosed in Figure 3, as viewed generally from below, illustrating the arrangement of the various magnetic core elements of the lower transducer and electrical connection thereof to wiring terminals;
• Figure 5 is an enlarged view in top plan of a flexure support configuration usable in the lower transducer assembly disclosed in Figs. 3 and 4, illustrating in phantom a transducer core positioned thereon;
• Figure 6 is a cross-sectional view of the flexure support illustrated in Fig. 5, generally as viewed along the Line 6-6;
• Figure 7 is an enlarged view in top plan of the lower transducer assembly illustrated in Figs. 3 and 4, with the transducer core portion thereof removed, illustrating the general mounted alignment of the flexure support of Fig. 5 within the housing portion of the lower transducer assembly;
• Figure 8 is a cross-sectional view of the lower transducer assembly disclosed in Fig. 7, generally viewed along the Line 8-8.
• Figure 9 is a view in bottom plan of the lower transducer assembly illustrated in Figs. 7 and 8;
• Figure 10 is an enlarged view illustrating the curved flexure axis portion of the flexure support disclosed in Fig. 6;
• Figure 11 is a view in front elevation of the transducer head assembly illustrated in Fig. 7, illustrating the position of the transducer core in phantom;
• Figure 12 is a view in top plan of an alternate embodiment of a support frame or housing portion of the lower transducer assembly illustrated in Fig. 7, depicting a recessed channel for receiving the outer frame of the flexure support structure of Fig. 5, and before insertion of the flexure support structure therein;
• Figure 13 is a view in bottom plan of the support frame disclosed in Fig. 12;
• Figure 14 is a cross-sectional view of the support frame disclosed m Fig. 13, generally viewed along the Line 14-14;
• Figure 15 is a cross-sectional view of the support frame disclosed in Fig. 12, generally viewed along the Line 15-15;
• Figure 16 is an enlarged side elevational view illustrating the relative angular positioning of the upper ramp portion of the transducer head assembly housing disclosed in Fig. 3, with relation to the edge of the transducer core mounted therein;
• Figure 17 is a front view, of the magnetic core assembly portion of the transducer assembly disclosed in Figs. 3 and 4;
• Figure 18 is a top view of the magnetic core assembly disclosed in Fig. 17;
• Figure 19 is a side view of the magnetic core assembly disclosed in Fig. 17;
• Figure 20 is a fragmentary view of the multiple transducer head and support apparatus illustrated in Fig. 2, illustrating the upper transducer support arm construction in cross-section and the lower transducer and support structure in phantom;
• Figure 21 is an enlarged top plan view of the gimbal flexure support member for the upper transducer, disclosed in Fig. 20; and
• Figure 22 is a diagram illustrating a lateral shift condition of a transducer head due to rotation of the transducer about a Y axis coordinate.
• a dual transducer head also referred to herein as electro-magnetic head
• electro-magnetic head support structure suitable for use in floppy disk data transfer systems, wherein data is transferred to and from both sides of a floppy disk.
• the invention will be described in association with its preferred embodiment application for use with a floppy disk data transfer system, it will be understood that the principles of the invention apply equally well to usage in other electro-magnetic transducer data transfer systems.
• the preferred embodiment of the invention will be disclosed with respect to a double sided floppy disk data transfer system, it will be understood that the principles of this invention apply equally well to single-sided data transfer systems.
• a fragmentary portion of generally planar flexible magnetic recording media is illustrated at 22, in the form of what is typically referred to in the industry as a "floppy disk".
• the floppy disk 22 generally comprises a rotatable pliant or flexible disk portion 22a housed within an outer protective jacket or envelope 22b.
• the floppy disk generally includes a central hub portion (not illustrated) which is operatively engaged by a rotatable spindle (also not illustrated) for rotating the inner flexible disk portion 22a, currently at speeds of approximately 360 r.p.m. within the protective covering 22b. It will be understood, however, that the invention also applies to other disk rotation speeds.
• the movable disk element 22a is constructed of a thin, flexible material such as polyethylene tetephthalate of approximately 0.003 inch thickness and has a magnetizable coating on its recording surfaces, such as an unoriented Fe 2 0 3 .
• data is written in magnetic form onto the magnetic surfaces of the disk.
• Such data is written in the form of spaced concentric tracks onto the disk 22a, one of which is diagrammatically indicated at "t" in Fig. 1, suitable for receiving and transmitting electro-magnetic data from and to respectively the electro-magnetic transducers, to be hereinafter described in more detail.
• the protective covering 22b of the floppy disk 22 has oppositely disposed and radially aligned slots 22c in its upper and lower protective layers , to expose the magnetic tracks (t) of the rotatable disk 22a for reading and writing operations by the magnetic transducer heads.
• a movable carriage a typical configuration of which may be used in such floppy disk systems, is generally illustrated at 24.
• the carriage 24 is radially movable, with respect to the floppy disk 22, by apparatus (not illustrated) for selectively positioning the transducer head assemblies carried by the carriage 24 at pre-selected radial positions along the floppy disk data recording media 22a, so as to select desired ones of the magnetic tracks (t) of the disk 22a.
• the particular carriage structure 24 and its indexing drive mechanism is relevant with respect to describing the transducer head support structure primarily to the extent that the carriage 24 provides a mounting base for the transducer support structures to be hereinafter described.
• the carriage 24 is also generally relevant for defining a Customer Reference Plane (C.R.P.), previously described. Further descriptions of the invention will presuppose that appropriate carriage 24 and carriage drive means
• a lower transducer head assembly (not illustrated) is present, for operatively aligning the transducer heads carried by the carriage 24 into operative alignment with a track (t) of the floppy disk 22a.
• a lower transducer head assembly (general designated at 30, is mounted to the forward or "free" end of the carriage 24.
• the outer configuration of the lower transducer head assembly 30 is formed, in the preferred embodiment, in the shape of an octagonal nut configuration, which has been typically referred to in the industry as a "button head" configuration.
• This particular outer shape of the lower transducer head assembly 30 has been used in the preferred embodiment, for its structural compatability with existing floppy disk carriage systems, such that the lower transducer head assembly 30 of this invention can be used to directly replace existing such "button head” structures.
• the lower transducer assembly 30 generally comprises an outer support frame or housing 31, molded in the preferred embodiment from a plastic material. Referring to Figs. 3 and 4 , the upper surface of the support housing 31 has an upwardly dished outer ring portion 31a, terminating at a generally flat circular plateau area 31b.
• the lower outer portion of the housing 31 defines a cylindrical collar, generally designated at 31c, another lower edge of which forms a land area suitable for bonding to the carriage 24. When bonding the housing 31 to the carriage 24, the lower land area of the collar 31c does not actually directly seat with the carriage 24, but floats in an adhesive bonding material, to enable accurate positioning and alignment of the transducer assembly 30 on the carriage 24.
• the housing 31 further defines an interior ledge portion 32 (see Fig. 4).
• Wire guide posts 33 project upwardly from the interior ledge portion 32, and the ledge 32 defines a plurality of support holes for electrical terminals, generally designated at 34 in Figs. 8 and 9. A plurality of electrical, terminals 35 are secured within the support holes 34, as illustrated in Fig : 4.
• the upper face or land area 31b of the housing 31 has a cutout, generally designated at 36, (Fig. 7), to receive. a magnetic core assembly 40 and portions of a flexure support structure, described in more detail hereinafter.
• the magnetic head or core assembly, generally designated at 40 may comprise any configuration of ceramic spacers and magnetic core members which when collectively bonded together generally define a read and/or write transducer head structure.
• the magnetic core assembly 40 is mounted to a flexure support structure 50, illustrated in more detail in Figs. 5 and 6.
• a flexure support structure 50 illustrated in more detail in Figs. 5 and 6.
• the flexure support structur 50 comprises a generally "cross" shaped primary flexure member 51, and an outer peripheral support ring or frame structure 52.
• Figs. 5 and 6 in the preferred embodiment the flexure support structur 50 comprises a generally "cross" shaped primary flexure member 51, and an outer peripheral support ring or frame structure 52.
• the flexure support structure 50 can better be described in structure and operation with respect to an X-Y-Z orthogonal coordinate system, wherein the X and Y axis coordinates lie perpendicular to one another; wherein the general plane of the central portion of the primary flexure member 51 lies in the X-Y plane; and wherein the Z axis coordinate lies perpendicular to the X-Y axis coordinates, the intersection of which form the origin of the coordinate system therewith.
• the primary flexure member 51 includes a central, generally rectangular planar land portion 51a, forming a mounting surface for the magnetic core assembly 40, the mounting position of which on the land area 51a, is illustrated in dashed lines in Fig. 5.
• the central land portion 51a of the primary flexure member 51 is resiliently mounted to the outer peripheral support ring or frame structure 52 by means of a plurality of flexure axes 51b laterally, extending from the central land portion 51a in cantilevered leaf manner in the X and Y axis directions.
• the outer terminals of the flexure axes 51b are sandwiched between and securely bonded to a pair of octagonally shaped frame members comprising the outer peripheral support ring or frame structure 52.
• the outer terminals of the flexure axes 51b are spot-welded to the pair of frame members comprising the outer peripheral support ring structure 52,. although other appropriate bonding techniques could be used.
• Additional material, generally designated at 51c is added at the juncture of the Y- direction flexure axes 51b with the central land area 51a, for strengthening the flexure axes which extend in the Y direction. This also enables the magnetic core assembly 40 to be positioned more closely to the lateral edge areas in the Y direction, of the central land portion 51a of the primary flexure assembly 51. This design minimizes the lateral spacing between the side wall of the magnetic core assembly 40 and the housing ramp surfaces, described hereinafter in more detail.
• a plurality of openings, generally designated at 54, are formed through the central land portion 51a of the primary flexure member 51, and permit the downwardly extending magnetic core members which collectively comprise the magnetic core assembly 40 to project downwardly therethrough, as indicated in Fig. 4.
• the edges of the plurality of openings 54 are also used to accurately align the magnetic core assembly 40 in predetermined position on the central land portion 51a of the flexure support structure 50.
• the primary flexure member 51 is blanked out of quarter-hard beryllium copper, which is subsequently hardened after forming, and is preferably from 0.003 inch to 0.004 inch thick. It will be understood that other materials could equally well be used for constructing the primary flexure member 51.
• the ring or frame members comprising the outer peripheral support ring structure 52 are of considerably thicker material (each approximately 0.012 inch thick in the preferred embodiment), so as to provide rigid support for the inner primary flexure member 51 secured thereto.
• the peripheral shape of the outer support ring structure 52 can be of any suitable configuration, to accommodate the particular structure of the support housing 31 to which the support ring structure 52 will be mounted. In the preferred embodiment, a generally octagonally shaped configuration has been found to be particularly suitable for cooperative mounting within the octagonally shaped support housing 31 structure. Further, while a
• cross shaped support configuration comprising the four flexure axes 51b has been illustrated for supporting the central land area 51a, a number of other configurations including more or less flexure axes are possible.
• a magnetic core assembly 40 is securely bonded to the central land portion 51a of the primary flexure member 51, and is aligned therewith so as to cover that portion thereof generally designated in dashed lines in Fig. 5.
• Outline drawings of the magnetic core assembly 40 used in the preferred embodiment are illustrated in Figs. 17 through 19.
• the upper surface of the magnetic core assembly is generally designated at 40a. While a generally planar core face 40a has been illustrated, it will be understood that the principles of this invention apply equally well for use with transducers having curved core faces and to spheroid core faces.
• the read/write "leg” of the core assembly is designated at 40b (Fig. 17) and the erase “leg” of the core assembly is designated at 40c.
• the read/write gap is generally indicated by the line at 40d and the erase gaps are indicated at 40e.
• those portions of the magnetic core assembly which bridge between those core pieces extending through the openings 54 are preferably fabricated by use of the retaining clip technique disclosed in U.S. Patent 4,152,742, issued on May 1, 1979, and incorporated herein by reference with respect to its relevant core structure and assembly teachings.
• Such retaining clips are generally indicated at 55 in Fig. 4.
• the appropriate read/write and erase coils are mounted to their associated downwardly projecting, core "legs" 40b and 40c respectively after the magnetic core assembly 40 has been bonded to the central land portion 51a of the primary flexure member 51.
• the central land portion 51a of the flexure will be generally rigid and inflexible.
• the leaf material forming the flexure axes 51b provides freedom of movement of the entire central land portion 51a in the Z axis direction (see Figs. 5 and 6), while minimizing rotational movement of the central land portion 51a and attached magnetic core 40, about either the X or the Y axis coordinates.
• the flexure axes 51b prevent rotational motion of the flexure central land area 51a about the Z axis coordinate and prevent friction-induced lateral shifting of the central land portion 51a in the X-Y plane, as hereinafter described in more detail.
• the central land area portion 51a of the flexure structure 50 which lies in the X-Y plane, will lie substantially parallel with the C.R.P.
• the Z axis coordinate is therefore perpendicular to the C.R.P., and is so defined for an assembled system.
• the electro-magnetic core assembly 40 is mounted to the flexure structure 50 such that the general plane of the upper surface 40a of the transducer head lies in an X1-Y1 plane that is parallel with the C.R.P. and perpendicular to the Z axis coordinate.
• the "origins" of the X-Y and the X1-Y1 axis coordinates respectively have been selected to lie at the geometrical centers respectively of the flexure central land portion 51a and of the upper surface 40a of the transducer head 40 (see Figs. 5, 6, 17, 18, and 22).
• the Z axis coordinate therefore, passes through the "origins" of the X-Y and the X1-Y1 axes. Distinction should be made herein between reference to movement about the Z axis coordinate which passes through the XYZ coordinate origin, and to movement in the Z direction, or Z axis direction (which refers to movement in the general direction perpendicular to the C.R.P.).
• the floppy disk employed with this transducer support arrangement operatively rotates in a manner such that its Nominal Disk Planes optimally lie parallel to the C.R.P., and therefore, also parallel to the X-Y and X1-Y1 planes. Therefore, when operatively mounted in the lower transducer support structure 30 , the upper surface 40a of the core establishes a reference plane for the floppy disk and for the upper transducer face (to be hereinafter described), which remains essentially parallel to the C.R.P., but which plane is free to move in the Z axis direction.
• the lower transducer assembly 30 is mounted on the carriage 24, relative to the operative position of the floppy disk, such that the upper surface 40a of the transducer core 40 (i.e. the X1-Y1 plane) slightly penetrates (i.e. lies slightly above, in the (+) Z axis direction) the lower Nominal Disk Plane of the floppy disk, to insure intimacy of contact between the floppy disk surface and the transducer core surface 40a.
• such penetration in the Z axis direction is approximately 0.008 inch.
• the nature of the flexure support structure suspension 50 is such that it permits very slight rotational motion of the central land area portion 51a of the flexure assembly about the X and the Y axis coordinates This "slight" rotation allows for better intimacy of contact between the transducer core face 40a and the floppy disk lower surface 22a during perturbations in movement of the floppy disk surface out of its Nominal Disk Plane.
• the flexure axes 51b are sized and shaped "stiff" enough such that they do not permit such rotational motion about the X or Y axis coordinates that would give rise to excessive lateral shifting which can produce data errors in the system as a result of misalignment of the transducer core face 40a (i.e.
• the stiffness and configuration of the flexure support structure suspension 50 practically eliminates friction-induced lateral shifts of the transducer core face 40a in the nominal X1-Y1 plane. Such lateral shifts can be caused by frictional drag forces on the transducer core face 40a as a result of sliding frictional engagement between the disk surface 22a and the transducer core face 40a.
• the stiffness and configuration of the flexure support suspension 50 also practically eliminates rotational motion of the transducer core face 40a about the Z-axis coordinate, in the X1-Y1 plane, and thus prevents misalignment offset errors between the transducer core 40 and the floppy disk recording track "t", thus enhancing data transfer.
• the freedom of motion of the flexure support structure in the Z axis direction, and its supported lower transducer core during steady-state operation and while remaining parallel to the C.R.P. improves the intimacy of the contact with the disk while maintaining core 40 and track (t) alignment and tends to iron-out surface irregularities of the disk again resulting in improved data transfer.
• the flexure axes 51b have been formed in a predetermined curve shape (as viewed in cross-section as in Fig. 6) .
• the shape of the curve is illustrated in more detail in the enlarged view of Fig. 10.
• a "delta Z" dimension of approximately (-) 0.006 inch in combination with the flexure structure illustrated and described has been found to be acceptable for enabling a flexure movement of the central land portion 51a in the Z axis direction of between 0.002 to 0.003 inch in response to the average impact forces during a loading oper tion, without any deleterious rotation of the central land portion 51a about the X or the Y axis coordinates.
• the left side of the drawing is that part of the flexure axis 51b that connects with the central land area portion 51a of the flexure assembly, and the right side of the flexure axis 51b is bonded to the peripheral support ring 52 of the flexure structure.
• a zero and preferably negative “delta Z” i.e. wherein the land portion connected end of the flexure axis is disposed in the Z axis direction relatively lower than the support ring connected portion thereof
• delta Z negative
• the flexure axes 51b will move in a dii-ection so as to "remove” path length from the flexure axes, rather than to supplement or add to the flexure axes path length, as would be the case if a "positive" "delta Z" condition existed.
• Such downward forces occur, for example, as a result of forces imparted to the lower core 40 by the upper arm and core assembly (to be described hereinafter in more detail) during a loading operation, or by disk perturbations.
• the shapes and dimensions of the plurality of flexure axes 51b are generally the same; however, they need not be to satisfy the spirit and intent of this invention.
• the widths of the flexure axes 51b are, in the preferred embodiment, approximately each 0.075 inch wide, and their operative length ("L" of Fig. 10, which equals the flexure axis 51b distance between the central land portion 51a and the interior edge of the peripheral guard ring or frame 52) is approximately 0.065 inch.
• the central portion of a flexure axis member 51b comprises concentric circular arcs having radii illustrated at Rl and R2, wherein the angle ⁇ lies approximately between 62-65°.
• the flexure member curvature within the first transition zone T1 comprises concentric circular arcs having relatively sharp radii illustrated at R3 and R4.
• the flexure member curvature within the second transition zone T2 comprises concentric circular arcs having relatively sharp-radii illustrated at R5 and R6.
• the combined length of the transition zones (Tl + T2) is 0.015 inch.
• transducer support flexure structure having a continuous flexure segment interconnecting a central land portion and a peripheral support structure, instead of a plurality of flexure axes, could be envisioned.
• a basic property to be retained by such a flexure structure is that movement of the central land portion of the flexure be resiliently permitted only in the Z axis direction, with rotation about either the X or the Y-axis coordinates being practically eliminated, except for minimal motion about the X and Y axis coordinates, to maintain intimacy of contact of the data transfer surface of a transducer head supported thereby with a rotating floppy disk surface.
• such minimal rotational motion about the X or Y axis coordinates is preferably an angular deflection only on the order of five to ten minutes.
• the lateral shift component of the transducer core face. 40a in the nominal Xl-Yl plane (i.e. the (sine ⁇ ) (D) component lateral shift previously discussed with respect to Fig. 22) , due to such rotational movement is minimal, and not likely to give rise to data transfer errors.
• a typical "D" dimension of 0.075 inches such lateral shift component equals 0.0001 to 0.0002 inches for an angular deflection of five to ten minutes.
• Another property to be retained by the flexure structure is that such structure practically eliminate lateral shifting of the central land region in the X-Y plane due to frictioninduced such lateral shifts, and also due to such lateral transducer face shifts caused by rotation of the transducer about the Z-axis coordinate.
• the flexure support structure 50 can be secured to the transducer support frame or housing 31 either by means of an insert molding technique or by a direct bonding operation.
• the housing.31 configuration illustrated in Figs. 3, 4, 7, 8, and 9 illustrates a support structure as it would appear if the flexure assembly were insert molded within the housing 31.
• FIG. 12-15 A preformed housing configurations 31', to which the flexure assembly is bonded, by non-insert molding techniques, is illustrated in Figs. 12-15.
• a groove or support channel 37 generally configured in the same peripheral shape as the peripheral support ring structure 52 of the flexure support structure 50, is formed around the cutout 36 ' of the housing 31 ' .
• the lower surface of the peripheral groove 37 forms a bonding seat for the outer peripheral support ring or frame 52 of the flexure support structure 50.
• the flexure support structure 50 is bonded to the housing 31' by an appropriate adhesive bonding material such as plastic or epoxy that is inserted within the groove 37.
• the transducer core members 40 are preferably attached to the flexure support structure after the flexure support structure has been bonded to the housing, to facilitate alignment.
• the core members 40 may be bonded to the flexure support structure 50 prior to bonding of the flexure support structure 50 to the housing 31'.
• the configuration, when viewed in top plan (Fig. 7) of the cutout 36 conforms generally in shape with the outer peripheral shape of the primary flexure member 51, but is slighty larger than that of the primary flexure member 51.
• the flexure axes 51b will not be covered by the housing 31 (or 31') or by any bonding material, they will be free to move so as to enable the central land portion 51a of the primary flexure member 51 to move in the Z axis direction, and parallel to the C.R.P., as previously described. It will be understood that for ease in describing and illustrating the position of the flexure support structure 50 within the housing 31, the magnetic core assembly 40 has been omitted from Figs. 7-9.
• a magnetic shielding ring 57 (see Fig. 4) is secured within the bottom recess portion of the housing 31, and the wires from the coils 56 are bonded to the appropriate electrical terminals 35.
• the upper surface of the housing 31 is shaped to form a pair of bifurcated ramps 38a and 38b, positioned immediately adjacent the cutout. 36 and bordering the flexure axes 51b in the Y axis direction.
• the ramps 38a and 38b provide a smooth continuous guiding surface rising from the circular land area 31b of the housing 31 to guide floppy disk 22 into proper operative position overlying the magnetic core assembly 40 during "insertion" of a floppy disk into the system.
• An enlarged view of the ramp 38a with respect to its relative positioning to the adjacent core assembly 40 is illustrated in more detail in Fig. 16.
• the apex of the ramp 38a lies slightly above the upper terminus of the sidewall portion of the core 40 such that an item such as a floppy disk (illustrated in phantom at 22) , rides smoothly over the ramp 38a surface and into smooth sliding engagement with the upper surface 40a of the magnetic core assembly 40.
• the core assembly 40 preferably also has a beveled edge (illustrated at 40aa) and preferably also has rounded corners (not illustrated) for further facilitating the disk insertion operation.
• the lower transducer flexure support structure above described can be used with single-sided floppy disk systems as well as with double-sided data transfer systems. Considerations in design of the various parameters of the flexure support structure 50 will depend in part upon the particular system with which the transducer structure 30 is to be used. In the case of usage with a doublesided floppy disk system, such design considerations must include the operative "loading" and "steady-state" parameters associated with the upper transducer support structure.
• the magnetic data transfer system 20 of the preferred embodiment is completed, for double-sided data transfer, by an upper transducer support structure.
• the upper transducer core 40 is generally oppositely disposed, with respect to the orientation of its electro-magnetic core elements, in relation to those same elements of the lower core assembly 40, to minimize data transfer interference between operations conducted by the upper and lower transducers respectively. It will also be noted from Figs.
• both the upper and lower transducer cores 40' and 40 respectively have channel regions 40g' and 40g respectively formed in their upper surfaces and running generally in the Z axis direction.
• This channel is illustrated in more detail at 40g Fig. 19.
• Such channels may or may not be present in transducer core designs.
• the channel has been found to prevent a "partial" or less than atmospheric pressure condition between the transducer core face and the disk surface that otherwise (due to Bernoulli's Principle), tends to exist as the disk rotates.
• the core channel acts as a "spoiler" slot in the transducer core face, to prevent the disk and transducer faces from being drawn toward each other during system operation.
• the upper transducer core assembly 40 ' is flexibly mounted by an appropriate gimballed support structure illustrated in more detail in Figs. 20 and 21.
• the core assembly 40' is directly bonded to a gimbal flexure member 62 illustrated in "top" view in Fig. 21.
• the gimbal flexure member comprises in the preferred embodiment a thin, sheet metal material having a plurality of cutout portions, generally designated at 62a, peripherally surrounding a central land area 62b to which the core assembly 40' is bonded.
• a plurality of bridge members, generally designated at 62c span the cutout portions 62a and interconnect the central land area 62b with the bordering frame material of the gimbal flexure member 62.
• This structure gives the central land area 62b freedom of movement in gimballike manner.
• a plurality of cutouts portions 64 formed within the central land area 62b, permit the core "leg" extensions of the read/write 40b' and erasure heads 40c' to pass therethrough (similar to the cutout portions 54 of the lower flexure assembly 50).
• the general plane of the gimbal flexure member 62 is designated in Fig. 21 by the plane of the X2-Y2 axes.
• the origin of the X2-Y2 axis coordinates is termed the "pivot point" and is generally located near the center of the arrangement of components comprising the active core portion 40', mounted on the flexure 62.
• the gimbal flexure is mounted to the upper arm 61 and is disposed in operative steady-state position as illustrated in Figs. 2 and 20, the X2-Y2 plane optimally lies parallel to the C.R.P.
• a rigid post 65 engages the upper surface of the gimbal flexure 62 at the "pivot point".
• the post 65 prevents motion of the upper flexure in the (+) Z axis direction at the pivot point, but enables "floating" universal pivotal gimbal movement of the central land area 62b in all other directions, about the pivot point.
• angular deflections of up to approximately 15 degrees from a Z axis passing through the pivot point are enabled.
• the gimballed movement of the upper transducer enables the upper transducer to maintain, in cooperation with the lower transducer, intimate contact with the floppy disk surfaces, even through perturbations in the disk surface motion which take the respective disk surfaces out of the Nominal Disk Plane.
• the upper support arm 61 is supported in cantilevered manner by a leaf hinge 70 (see Figs. 1 and 2).
• a leaf spring 71 exerts a fixed downward force in the (-) Z axis direction on the upper transducer 40', which force is exerted to the floppy disk and through the floppy disk to the lower transducer.
• the leaf spring 71 exerts a force on the upper arm which produces a force of approximately 15 grams between the transducer heads, to insure intimacy of contact between the transducers and the floppy disk.
• the upper transducer core face 40a' is designed to be movable relative to the lower transducer core face 40a such that the two core data transfer faces are always parallel to each other, with the distance between the core faces being equal to the instantaneous thickness of the rotating floppy disk. This condition insures intimacy of contact between the opposed transducer core faces and the engaged surfaces of the floppy disk, even through perturbations in movement of the floppy disk surfaces out of their Nominal Disk Planes.
• the spring biasing support arrangement for the upper support arm 61 illustrated in Figs.
• the present invention when incorporated within either a single or a double-sided flexible disk data transfer system, offers improved performance over prior art structures both during the transient
• Loading is that process wherein opposing surfaces of a rotating floppy disk are engageably sandwiched, preparatory to data transfer, between a transducer head and a pressure pad (for single-sided data transfer) or between a pair of opposed transducer heads (for double-sided data transfer).
• a transducer head support structure that incorporates the flexure support principles of the present invention (such as that disclosed at 50 in the preferred embodiment) will be simply referred to as the Z Axis Flexure Structure. While the following discussions will refer to the particular flexure support structure (50) described in the Drawings and the specification, it will be understood that such Z Axis Flexure Structure, terminology is not intended to limit the scope of the invention to the structure of the preferred embodiment, but that all variations thereof, as limited only by the claims, are included.
• any such data transfer system will assume that the Z Axis Flexure Structure is employed to mount a transducer head or core within the "lower" or “bottom” head assembly of such system.
• the Z Axis Flexure Structure of this invention acts as a resilient shock absorption device during a loading operation.
• the upper force-imparting slider member pressure pad or upper transducer head
• the upper force-imparting slider member forcefully engages the floppy disk with a relatively large impact force and sandwiches the floppy disk between the upper force-imparting member and the lower transducer slider head which is supported by the Z Axis Flexure Structure.
• the direction of the loading impact force is primarily in the (-) Z axis direction (with reference to the axes defined in the Drawings hereof).
• the impact force is transmitted through the floppy disk and the lower transducer head, to the Z Axis Flexure Structure. Upon initial receipt of such loading impact force, the Z Axis Flexure
• Structure will respond by allowing the lower transducer supported thereby to initially move in the (-) Z axis direction.
• the flexure land area 51a will move in the (-) Z axis direction, in a manner generally parallel to the
• the Z Axis Flexure Structure will absorb some of the kinetic energy imparted thereto by the accelerating upper head or pressure pad mass, and will convert it to potential energy - resulting in a damping action.
• the Z Axis Flexure Structure After the Z Axis Flexure Structure had reached its maximum deflection in the (-) Z axis direction, it will release some of its potential energy by reversing its direction of motion, and by moving in the (+) Z axis direction.
• the damping process i.e. physical "settling" time
• wi11 continue until a state of "average equilibrium" is reached.
• the initial loading impact force will vary depending upon many factors such as the height of .the "drop" of the pressure pad or upper transducer and the preload force of the leaf spring 71.
• configuration of the Z Axis Flexure Structure when used with the double sided data transfer structure disclosed herein, peak deflections of the flexure central portion 51a, of less than 0.003 inch in the (-) Z axis direction are desirable for average upper arm drop heights during loading conditions.
• the shock absorption and mechanical damping features of the Z Axis Flexure Structure during loading operations softens the transducer engagement with the floppy disk, as compared to rigid transducer support structures, thus providing increased disk life.
• the improved damping feature may also enable drive manufacturers to eliminate costly electrical networks presently used to control load/unload solenoids.
• the flexure axes 51b of the Z Axis Flexure Structure are configured to substantially prevent any rotational motion of the flexure central land portion 51a about the X or Y axis coordinates, even under significant Z axis direction movements such as experienced in a transient state loading operation, the damping movements of the Z Axis Flexure Structure during the physical settling time following loading impact, should not introduce data-causing errors, due to lateral shifting of the lower transducer core surface in the X or Y axis directions, relative to the selected recording track (as previously discussed).
• the! upper and lower transducers and the floppy disk will be disposed in their "steady-state” operative positions.
• the "nominal" position of the lower transducer 40 supported by the Z Axis Flexure Structure when in its loaded condition, is prepositioned such that the disk engaging surface (i.e. the disk surface in the X1-Y1 plane) of the lower transducer head core slightly penetrates into the lower Nominal Disk Plane of the floppy disk - to insure intimacy of contact during steady-state operation.
• the present invention improves data transfer and minimizes data errors inherent with prior art double-gimbal structures, due to transducer misalignment shifts relative to the recording track data.
• the floppy disk rotates, it will experience some perturbations in movement out of its Nominal Disk Planes, due to for example, wobble and surface imperfections. Such perturbations will produce forces primarily with vector components in the Z axis direction, which will impart kinetic energy to both the upper and lower head assemblies.
• both the spring-biased, gimbal supported upper transducer and the lower Z Axis Flexure Structure will respond to these forces.
• the comparative response modes of the upper gimbal support. structure and the Z Axis Flexure Structure will, however differ (i.e. they will display differential relative movement compliance to such forces, when compared with one another).
• the upper gimbal support structure is free to move in universal manner in all directions about its fixed pivot point, except for in the (+) Z axis direction.
• the Z Axis Flexure Structure is substantially prevented from moving in any direction ( as above described) except for movement in the Z axis direction, and will exhibit a fairly stiff response movement.
• the Z Axis Flexure Structure is able to respond primarily with Z axis deflection and with some rotational deflection about the X and Y axis coordinates, in conjunction with the gimbal movement of the upper head, allows for improved disk-to-transducer data transfer contact at very slight expense of X and Y location errors. Such errors or lateral shifts are significantly reduced as compared to prior art shifts inherent in the double-gimbal transducer support structures.
• the present invention also provides improved "steady-state" operation as compared with double-gimbal prior art devices by offering improved resistance to lateral shifting forces in the X-Y plane caused by frictional forces exerted on the lower transducer head by the rotating floppy disk.
• the floppy disk rotates with its surface in sliding frictional engagement with the lower transducer head, it imparts lateral shifting forces through the Tower transducer head to the flexure land area 51a, which translate as vector forces within the X-Y plane of the flexure land area 51a.
• the flexure axes 51b are of sufficient width so as to effectively prevent such lateral displacement.
• the flexure axes 51b oriented in the Y axis direction will tend to prevent transducer displacement caused by vector forces in the X axis direction, and the flexure axes 51b oriented in the X axis direction will tend to present transducer displacement caused by vector forces in th Y axis direction. Therefore, the Z Axis Flexure Structure of this invention provides improved operative results not only by its shock absorbing damping properties during transient loading operations, but also by its improved intimacy of contact and reduced rotational and shifting movement during steady-state data transfer operations.
• the structure of the present invention is much simpler and less expensive to construct and to maintain than the double-gimbal structure. Further, the more rugged construction of the lower transducer support structure enables the present invention to use larger applied forces between the upper and lower transducers, as compared to double-gimballed structures and as compared to fixed lower head structures.
• the design parameters for the various portions of the lower transducer support structure are necessarily related to the downward force applied to the lower magnetic core assembly 40 within the particular data transfer system used - either by an upper pressure pad in a single-sided system, or by the upper transducer and associated spring-biased support arm structure in a double-sided system. Accordingly, it will be recognized that not only the basic configuration and shape of the flexure support structure 50 itself can be varied within the scope of this invention, but that there is also considerable design flexibility for altering the basic parameters of any particular configuration of the flexure support structure.
• the thickness and type of flexure material can be varied, and such variation can be uniform or selective with respect to various portions of the flexure assembly.
• the size (i.e. length, width and thickness) of the flexure axes can be varied independent of the dimensions of the rest of the flexure.
• the geometric cross sectional shapes and configurations of the flexure axes can be varied, as well as the number and position of the flexure axes relative to the central support land portion 51a of the flexure assembly. It will be understood that the value of "delta Z" can also be varied.
• the shape and configuration of the central land area 51a relative to the flexure axes 51b can be varied.
• the shape and configuration of the outer peripheral support ring or frame portion 52 of the flexure support can be changed, and even eliminated altogether in favor of another method of securing the flexure axes or central land portion of the flexure assembly to the supporting housing 31.
• Other variations included within the scope of this invention, will also be apparent to those skilled in the art.

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• Supporting Of Heads In Record-Carrier Devices (AREA)

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• 1980
  • 1980-09-15 NL NL8020408A patent/NL8020408A/nl unknown
  • 1980-09-15 DE DE803049954T patent/DE3049954A1/de not_active Withdrawn
  • 1980-09-15 GB GB8115642A patent/GB2071394A/en not_active Withdrawn
  • 1980-09-15 WO PCT/US1980/001187 patent/WO1981001071A1/en active Application Filing
  • 1980-09-15 JP JP50255280A patent/JPS56501303A/ja active Pending
  • 1980-09-15 AU AU64812/80A patent/AU6481280A/en not_active Abandoned
  • 1980-10-01 IT IT25064/80A patent/IT1133651B/it active
  • 1980-10-02 FR FR8021123A patent/FR2466827A1/fr not_active Withdrawn
  • 1980-10-03 BE BE0/202338A patent/BE885537A/fr not_active IP Right Cessation
  • 1980-10-06 PL PL22711980A patent/PL227119A1/xx unknown

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