FR2466832A1 - TRANSDUCER-REPORTER ASSEMBLY FOR A DOUBLE-SIDED SOFT DISK - Google Patents

Abstract

The present invention relates to a transducer-arm assembly usable with a flexible recording disc. The assembly is characterized in that it comprises in combination: - an elongated body 36 comprising first and second opposite faces and provided with an opening passing therethrough near a first end and between said faces; a hinge 43 provided at the second end of said body 36 so as to connect the latter to a supporting element; an essentially planar flexion element 65, comprising a central part which is hollowed out and profiled so as to allow a pivoting movement of said central part about axes X, Y which are mutually perpendicular and situated normally in the plane of said element 65; (CF DRAWING IN BOPI) - a transducer 32 mounted on said flexion element so as to partially engage said openings; a means 64 ensuring the attachment of the flexion element 65 on one face of said arm 35 so as to extend transversely to said opening formed therein; and - a cover 120 serving to close the opening formed in the arm on its second face, said cover comprising a lifting tab 122, positioned so as to project laterally from the arm, and a pivot 133 positioned so as to enter said opening to come into contact with the bending element 65 at the point of intersection of said X, Y axes. The invention relates to devices for reading / writing data and information.

Description

ad 2466832

  TRANSDUCER ASSEMBLY FOR A DOUBLE-SIDED SOFT DISK.

  The present invention relates generally to apparatus

  magnetic recording, and it relates more specifically to

  upgrades to support structures for electronic transducers

  magnetic devices of the type usable more specifically with a memory system

  data on magnetic disks for data transfer

  between the transducer and a flexible magnetic disk.

  The condition imposed on all magnetic storage systems of

  This data consists in the fact that they must contain a magnetic recording

  very data for storing data in a magnetic form and an electromagnetic transducer having one or more "heads" for "reading" and / or "writing" data in magnetic form,

  respectively from the recording medium and on said medium.

  Although such magnetic data storage systems have used data recording media of different configurations (such as tapes, rigid disks and drums), the so-called medium

  "floppy disk" has recently been widely used, not only in

  plications involving memorization and program entry

  but also in a number of diverse applications involving

  come input and storage of data and fulfilling control functions. "Floppy disk" is a thin, generally planar, flexible or collapsible disk, which has magnetically sensitive surfaces and can commonly rotate at speeds of about 350 rpm, within an envelope or a protective cover. The transfer of data to and from the flexible disk is provided by one or more electromagnetic heads which are disposed within a transducer. The transducer (or transducers) communicate with one or both surfaces of the flexible disk through openings

in the protective envelope.

  We know a number of transducer structures that are

  usable for establishing communications with flexible disks.

  In general, the parts of these transducers that respond to electromagnetic data transfer to and from the flexible disk do not exhibit significant differences in their basic components. Each transducer basically comprises a plurality of magnetic cores which are pre-positioned relative to each other, and which are attached together and interconnected with one or more coils to define

  an electromagnetic transducer operating correctly.

  For the most part, such transducer structures, when used in data transfer operations to and from a floppy disk, include a single-channel read / write head and

  they can typically also include an erase head.

  The erasing head generally has a plurality of erasure cores for erasing a "track" of information recorded on the surface of the floppy disk and also for erasing a pair of strings.

  guard which are provided on each side of the aforementioned track.

  In the context of the present invention, the particular details of structure and relative positioning of the electromagnetic components which constitute

  collectively the different parts of the heads of an electronic transducer

  The present invention is equally applicable to any type of transducer and electromagnetically operable head components, whether multiple or single heads, erase heads, reading, writing, or

  combinations of read / write heads.

  In single-sided recording systems which were initially

  used, the electromagnetic transfer of data between the transducer

  and the floppy disk can only be on one side of the disk at a time.

  Efficiency is greatly improved with an active double-sided system.

  In this system, it is possible to transfer data with both sides of the floppy disk simultaneously. This is made possible by using a pair of transducers placed facing each other and arranged so that the flexible disk is interposed between them, thereby entering

  simultaneously in contact with both sides of the flexible disk.

  In single-sided active and double-sided active disk systems respectively, the respective transducer assemblies are typically installed on a movable carriage that is presented or indexed in a relatively fixed position relative to a flexible disk. A movement of this carriage allows the transducer or transducers carried by it to access

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  different desired circular "tracks", which are placed in

  different radial conditions on the magnetizable surface of the flexible disk.

  The placement position of the movable carriage must be aligned and controlled relative to the nominal plane of the disk, which is defined as the plane in which a surface of a flexible disk is nominally placed during the functional rotation of the disk. Since a floppy disk has two data transfer surfaces that are separated by the thickness of the disk, a system

  double-sided active involves two nominal planes of the disc, generally

  called the "upper" nominal plane and the "lower" nominal plane.

  In an optimally operating system, except for the portion of the flexible disk that is in contact with the transducers, it is desirable that the two data transfer surfaces of the flexible disk be placed, in a perfectly flat condition, respectively in the planes. the imperfection, such as swaying or distortion caused for example by the defects of the disk itself, by the flexible nature of the latter, or by a movement transmitted to the disk. disc by the device ensuring its rotation training. Flexible disk data transmission systems include

  different designs depending on the support structures of trans-

  ductors that are installed on the mobile cart. In systems operating on an active single-sided floppy disk, the transducer generally has a curved surface, intended to come into operative contact with the floppy disk and to penetrate into and beyond the nominal plane of the disk defined by the data transmission surface. . The transducer is generally mounted in a fixed position on the movable carriage. A hinge arm bearing a pressure pad is pivotally mounted on the carriage to allow entry of the disk. The arm is spring-loaded so that the pressure pad carried by the latter comes into contact with the disk in a position

  directly opposite to the transducer head and applies to it a

  in order to bring the flexible disk into intimate contact with the curved head of the transducer. This known single-sided active system has shown a limited capacity for data transmission since this data transfer can only be performed on one side of the disk at the same time.

  both times and that, in addition, this process is relatively slow.

  Changing requirements for data access and data transmission capacity and speed have led to the development of flexible disk systems that provide double-sided data transfer.

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  these systems having the possibility of simultaneously transferring data with both sides of a flexible disk. As indicated above, such systems generally include two transducers, mounted to contact opposite surfaces or sides of the flexible disk, generally in positions facing each other. The opposing transducers are generally positioned so that the respective air gaps of their heads are slightly radially offset relative to one another so

  to minimize the interaction of magnetic fluxes between transduc-

  tors. In such active double-sided disk data transfer systems, the upper and lower recording surface areas

  of the floppy disk may be periodically deviated from the higher nominal

  respective lower and lower sides of the disc. Such deviations may, for example, be caused by deformation of the disks, or by excessive undulation of the disks (i.e. disturbances occurring in the surface of the disk during its rotation). It has therefore been considered desirable to allow displacement of the transducer heads, placed in opposite positions with respect to each other, so that

  said heads can follow the real path traveled by the surfaces of

  record the floppy disk passing between them, when they deviate

  said higher and lower nominal planes of the disk.

  As a result, in the past, different structures of

  Transducer stage, intended to absorb such deviations during the movement

rotation of a flexible disk.

  Thus, in US Pat. No. 29,380, there is described a method of mounting two transducer sliding heads facing one another on two fixed support arms, the two heads being able to to be moved, under the action of a solenoid, towards the disk in an operation of

  "loading" and, from the disk, during an "unloading" operation.

  The support arms come into contact with stops provided on a carriage

  to limit the closing distance between them to a predetermined value.

  completed and fixed. The opposite heads of the transducer are pushed to contact with the disc by means of two helical springs, which are placed in

  below the heads so that the flexible disk is interposed between them.

  As has been described in more detail in the US patent application filed under the title "Z-Axis Flexure Suspension Apparatus" on October 5, 1979, under No. 82,009 by the Applicant, a this structure is affected by certain disadvantages as regards the lack of sensitivity to variations of the flexible disk, the introduction

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  errors in data transfer, which are caused by a shift in

  in relation to the recording tracks, a slow damping response as a result of a loading operation, and a reduction in the intimate contact between the transducer heads and the recording surfaces of the floppy disk. Another variant of a dual transducer support device has

  has been described in U.S. Patent No. 4,089,029.

  In this structure, two transducers mounted on long and cantilever carrying arms are mechanically pushed towards each other under the action of a spring, each transducer being mounted independently on a mechanism of articulation which allows a universal pivoting movement of the respective heads of the transducers. The disk contact surfaces of the transducer heads are generally planar. Swiveling support arms

  are coupled with each other so that a movement of an arm having

  to raise one of the transducers away from the surface of the disk also causes movement of the second arm so that the second transducer is moved away from the opposite surface of the disk for loading.

  and unloading the disk into and from a service position.

  Each arm is pushed with a predetermined force against the corresponding face.

  This tends to maintain an intimate contact between the transducer carried by this arm and the corresponding contact surface of the disc. The composite structure allows the interposition of the flexible disk between the opposite transducers, but the loading force is relatively low,

  namely 6 to 7g, which tends to produce instability.

  Also, although the double-articulated structure is arranged to allow the transducer heads to respond quickly to gaps by

  compared to the nominal plans of the disc during its movement, these movements

  Follow-up operations performed by the heads cause offset or eccentricity errors. In addition, the system is very complicated and it is

expensive manufacturing.

  A relatively recent design of an active double-sided floppy disk data transfer system has been claimed in U.S. Patent No. 4,151,573. This structure is arranged to enhance intimate contact. between the disc surfaces and the transducers and to eliminate some of the disadvantages encountered with

  support structure of double universal joint transducers.

  In this structure, an asymmetric support carrying a first transducer, or lower transducer, provided with a planar core surface which is disposed in a fixed and immutable position (as in

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  known single-sided transfer). A second (upper) transducer is mounted on a universal joint structure, and is pivotally displaced by a spring-loaded arm to a position near the fixed lower transducer so that the flexible disk is interposed between the two transducers and subjected to a predetermined force. The lower transducer is provided with a surface. useful relatively more

  larger than that of the upper transducer so as to exceed

  the dimensional contour of the upper transducer.

  The surface of the core of the lower transducer is arranged to penetrate

  excessively in the nominal plane of a loaded flexible disk, and the transduc-

  top carrier carried by the universal-joint bracket-acts as a

  pressure pad on the fixed lower transducer. Conversely, the transduc-

  stationary lower head acts as a pressure pad on the upper transducer.

  Although this structure makes it possible to reduce, to a certain extent, the errors due to an offset and an eccentricity during the tracking movement, it is nevertheless affected by a poor positioning of the lower transducer relative to the recording tracks of the surface. lower

  of the flexible disk, because of the attachment of this transducer.

  The structure according to this patent also has the disadvantage of excessive wear of the flexible disk under the effect of shocks quite "strong" exercised

  by the upper transducer during system loading.

  All these disadvantages of the known achievements are eliminated through the set

  carrier-arm transducer according to the present invention.

  According to one aspect of the present invention, there is provided a support arm

  Transducer for use with a data recording system on an active double-sided floppy disk. The arm has an elongated body, which is provided with a first and a second face positioned opposite one another, an opening being formed in the body near the first end of the arm. It is provided at the second end of the arm an articulation

  establishing a connection with a carrier element of a transducer assembly.

  A substantially flat bending element, which has a recessed central portion and shaped so as to allow universal pivoting movement of the

  central part around mutually perpendicular axes which are normal-

  placed in the plane of the said element, is attached to the first end of the

  arm, while a transducer is mounted on the bending member.

  A cover, which is constituted by an independent piece nestable in the preferred embodiment, is provided to ensure the closure of the opening in the arm. The lid includes a lifting tab, which is positioned to protrude laterally from the arm, and an adjustable pivot positioned to enter the opening for contact with the arm.

  bending element at the point of intersection of the axes of the universal joint

  towards her. According to a preferred embodiment of the invention, the

  pivot is constituted by an adjustable fixing screw.

  According to another aspect of the invention, a connector panel

  is fixed on the central part of the bending element in an adjacent zone.

  to the transducer. A conductive member, preferably a flexible strip positioned along the arm in a recess, provides the connection between a cable and the connector panel, which comprises eyelets extending, at

  through conductors of the flexible band, in the connector panel.

  Windings forming part of the coils of the magnetic transducer may be wound around the eyelets, and the eyelets and the flexible band may

  be brazed simultaneously on the panel's connecting eyelets.

  According to another aspect of the invention, the hinge provided at the second end of the arm may comprise a blade hinge, as well as

  means for blocking the blade, this locking means comprising a plurality of

  sieurs passages intersecting between them so that a conductive cable, connected to the transducer placed at the end of the arm, can be engaged in one

  said passages for connection to an external system.

  A thrust spring of the arm is fixed on the locking means so as to cover the intersection passages in order to further contribute to maintaining

in position of the cable.

  According to yet another aspect of the invention, the body of the transducer arm has a recessed portion in the flat bottom surface,

  in an area adjacent to the end of the arm that is remote from the transducer.

  There is a blade hinge and two locking plates. The locking plates are connected to one end of the blade hinge, preferably by spot welding, and this composite structure is connected to the arm so that one of the locking plates engages in the recessed portion provided in the lower side of the arm. The locking plates have opposite straight edges that contact the hinge and cooperate with each other.

  with the latter so as to define a pivot axis for said hinge.

  Preferably, the outer surface of the lower blocking plate is generally coplanar with the generally planar lower surface of the

arms.

  According to yet another aspect of the present invention, there is provided an improved magnetic transducer for use in a magnetic disk data storage system. This transducer includes a body

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  formed of a core and ceramic parts which are provided with a flat face

  in which the recording or read / write gap is positioned.

  In use, the transducer is positioned so that the planar face is in contact with the recording medium, constituted by the disk, in order to perform data transfer operations.

  In the case of a dual-sided flexible disk recording system,

  In this case, two transducers of the type defined above are used, and means are provided for supporting the transducers and moving them into a data transfer position where the transducer faces are in mutual contact with the recording disk. on opposite sides of it. Each transducer has beveled edges that are connected to the

  flat face. In addition, the corners formed by the intersection of these adjacent edges

  cents are bevelled, preferably with a bevel of conical section which

  gradually join the bevelled edge provided on one side or the other of the corner.

  In addition, all edge and wedge bevels gradually join the flat face of the transducer by means of fillet to avoid surface discontinuities. By beveling the corners, unwanted stress concentrations, which can cause wear, are eliminated in the case of contacting a corner of the transducer body with the

  recording medium during loading or unloading operations-

support.

  In the case of an active double-sided system where the first transducer is mounted on a loading arm which is swiveled away from the second transducer for insertion or removal of a flexible disk and which is subsequently brought into contact with the disk for carrying out data transfer operations, the bevels provided on the first transducer are preferably oriented at an angle of about 150. The bevels provided on the second transducer are , preferably oriented at an angle of about 30, to facilitate insertion and removal of the flexible disk, when it is necessary to provide engagement and transverse displacement by

  relative to the transducer during an insertion or removal operation.

  In accordance with the present invention, there is provided a trans-

  advanced magnetic drive for a data storage system

  magnetic disk, comprising a transducer provided with a flat face of

  to come into contact with the recording disc during opera-

  data transfer, and a crankcase to position the trans-

  conductor so that its face protrudes from said housing for effective contact with the recording medium constituted by the disk when

  it is in a data transfer position.

  A guide ramp is provided on the housing, or, preferably, it is an integral part of said housing. The ramp is placed in a position

  adjacent to the transducer, and is inclined from the housing to the transducer

  for guiding the edge of a recording disk on the face of the transducer when this disk is being inserted into the transducer assembly. A second ramp may be provided on the casing on the opposite side of the transducer so as to guide the protective casing of a "diskette" on the transducer when

  removal of the "diskette" from the transducer assembly.

  Advantageously, a bevel is provided on the edges of the transducer which are adjacent to the ramp in order to further facilitate the guiding of the disc.

  the transducer relative to the transducer during

sertion or removal.

  Other objects and advantages of the present invention will be apparent from

  reading of the following description and accompanying figures given as

illustrative but non-limiting.

  Figure 1 is a perspective view of a magnetic transducer assembly according to the present invention, parts of which are indicated

  in snatched view to clarify the drawing.

Figure 2 is a view

on an enlarged scale.

  Figure 3 is a view Figure 4 is a view

enlarged scale.

Figure 5 is a view

transducer of FIG. 1.

  Figure 6 is a view Figure 7 is a view

used in said set.

Figure 8 is a view

of Figure 1.

  Figure 9 is an exploded view of a portion of the assembly of FIG. 1

  in section, taken on the line 3-3 of FIG. 1.

  fragmentary, similar to FIG. 3, but to a bending element used throughout

  a flexible cable used in said assembly.

  from below an interlocking independent element in fragmentary section, made on the fragmentary line 8-8, similar in general to FIG. 4 but represented on a still enlarged scale, parts being

omitted or indicated in-section.

  Figure 10 is an enlarged bottom view of a first transducer.

  Figure 11 is an enlarged plan view of a second trans-

  ducer. Figure 12 is an enlarged fragmentary detail view of a portion of the transducers of FIG. 9, the support

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  registration being omitted; and Figure 13 is a partially schematic view showing the insertion

  a "diskette" in the transducer assembly.

  In Figure 1, there is shown a portion of a "floppy disk", also called "diskette" in a data transfer position by

  relative to a transducer assembly according to the present invention.

  Because of space limitations in Figure 1, most of the floppy disk has been removed. This flexible disk is formed by a thin disk 20, nominally plane and made of a flexible material whose surfaces are coated with a magnetizable material. The disk 20 is housed in a protective envelope 21. This envelope 21 has radially extending, upper and lower slots 22, which, as also shown in FIG. 9, are arranged between inner ends 23 and ends

  24 to define zones of access of the transducers to the sur-

  sides of the disc. Classical training methods (nonrepresented) are

  felt) to ensure a rotation of the disc 20 inside the envelope 21,

  as indicated by the arrow 25 in FIG.

  because it is maintained in place by appropriate means

  guide (not shown), in a generally known manner.

  A carriage generally designated 30 is provided to support and move the transducers, as will be explained in detail later. The carriage 30 is connected in practice to a lead screw or other positioning member, as is generally well known, in order to produce a radial displacement of the carriage in order to bring the transducers into contact with the circular tracks. recording of the disc 20, which are divided

  with different radial spacings.

  As shown more clearly in Figures 4 and 9, two transducers 32 and 33 are supported by the carriage 30 so as to be in contact with the recording medium. For convenience, in the continuation of the

des-

  In the description, the transducer 32 will be called the "upper transducer" or the "upper head", while the transducer 33 will be called the "lower transducer" or the "lower head". However, the terms "upper" and "lower" are used simply for convenience of identification and they do not imply a need for positioning, since the set of heads could also be incorporated into a recording system on "diskettes". "placed on the field, or" returned "with respect to the orientation indicated in the figures, or having any other desired orientation. 2466832 The upper transducer 32 is connected to the carriage 30 via a carrier arm structure which will be described in more detail below. The assembly constituted by the upper transducer and the arm

  can operate in cooperation with a fixed lower transducer and

  of the type claimed in U.S. Patent No. 4,151,573, mentioned above, or, preferably, with a transducer having a Z-axis flexible suspension, as defined in the application of

patent mentioned above.

  With both a fixed lower transducer and a transducer

  Z-axis suspension, the function of the upper transducer assembly

  arm is to maintain the transducer in a contact and alignment position.

  Correctly relative to the flexible disk 20, the transducer faces being parallel and in intimate contact with the recording surfaces of the disk

  to ensure optimal data transfer.

  As indicated in the above-mentioned patent application, this

  This task can be completed in the best possible way by

  Z-axis pension for the lower transducer 33; however, in either case, the improved upper-arm transducer assembly which will be described hereinafter facilitates the transfer of data in an efficient manner.

and sure.

  As shown in the figures, and particularly in Figure 2, the arm comprises a body 36 which is preferably formed by molding a plastic or other electrically non-conductive material and weight

  light, although this material is not required to be nonconductive.

  The body 36 has a generally flat lower surface 41, one end of which is recessed, as indicated at 42, so as to receive a blade hinge 43. This blade hinge comprises an elastic blade 44, which is preferably formed of a suitable elastic metal and one end of which is adapted to engage the recessed portion 42 of the body 36, while its opposite end is profiled so as to allow attachment to a base 50, or any other locking means. The overall width of the blade hinge 44 is chosen according to the width of the body 36 and the base 50

  to obtain the desired degree of torsional stiffness.

  The blade hinge 44 is preferably recessed in the central portion, or flexible, so as to minimize its stiffness or bending strength, since the hinge is only used to perform a hinge function and not the hinge function. an elastic tension element,

  since a separate spring 55 is provided for this purpose.

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  The left end of the blade hinge 44 of FIG. 2 is spot welded between upper and lower support plates 45 and 46, this composite structure being fixed in the recessed portion 42 of the body 36 using

appropriate organs 47.

  In known embodiments, it is common practice to embed

  the end of the blade hinge in the body of the transmission support arm

  driver during the molding operation. However, the improved structure

  described above with reference to Figure 2 offers several important advantages.

  tives. In particular, the straight edges of the retainer plates 45, 46 form a straight-line locking edge that defines the beginning of the flexible portion of the blade hinge. Another advantage is that blade hinges of different shapes and sizes can be made, which is possible

  to fix on a single type of body 36, so that only one transducer-

  arm can be adapted to different blade hinges for connection to different types of trolleys made by different manufacturers, which

  helps improve manufacturing costs and cost.

  In the preferred embodiment, there is provided a base 50 and a

  locking piece 52 for fixing the outer end of the blade hinge.

  The base 50 is fixed on the carriage by a suitable member such as a screw 51.

  Alternatively, it can make the base 50 secured to the carriage. This base 50 has a generally flat upper surface oriented parallel to the lower transducer face and terminating in a straight edge 58 which defines the other axis of flexion of the blade hinge 44 as the arm moves downwardly. The outer end of the hinge 44 is placed at the top of the base 50 and is held in position. : place by a blocking piece 52 and appropriate fasteners 53 which pass through the piece of

  blocking and blade hinge to penetrate the base 50.

  The inner edge of the locking piece 52 is provided with a rounding, as indicated at 54, in order to distribute the stresses in the blade hinge 44 when subjected to upward bending, for example during

an unloading operation.

  The arm 35 is pushed down towards the flexible disk by a spring 55 pressing against the upper surface of the arm and fixed at the top

  of the locking piece 52 by means of a support plate 56 and fasteners 57.

  The upper surface of the base 50 is oriented parallel to the plane of the face of the lower transducer. The height of the base 50 is chosen so that the face of the upper transducer is oriented, at a time just prior to coming into contact with the surface of the disc in an operation of

  loading, parallel to the plane of the lower transducer face.

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  The end of the body 36 which is remote from the hinge 43 is provided with an opening 60 of rectangular profile, which comprises near its base a flange 61 at one end and two spaced edges 62, 63, at its other end.

  end: the edges all have the same height relative to the surface 41.

  A bending member 65 is attached to the underside of the outer end of the body 36 by spot welding on the passing fasteners 64.

  through the arm in the positions shown in Figure 2.

The bending element has been shown in greater detail in FIG. 5 and is formed of a thin piece of a nonmagnetic elastic material,

  know of stainless steel in the preferred embodiment.

  Different parts or areas were stripped off to form a two-axis hinge or cardan. A rectangular central part 66

  is connected continuously, through narrow and symmetrical bands

  67, to a ring 68 of rectangular shape. This ring 68 is itself connected, by opposite strips 69, to the outer portion 70 of the bending element. It goes without saying that the central part, the ring and the connecting strips mentioned above are all part of the same initial strip from which the other areas have been removed by stripping to form

the structure described.

  The transducer 32 is attached to a portion of the central zone 66, as described below, and the bending member defines a two-axis X-Y joint or cardan for the transducer. Specifically, the Y axis passes through and is defined by the bands 67, while the X axis crosses in a similar way

bands 69.

  Transducer 32 consists of a composite or sandwich structure consisting of core pieces and ceramic spacer pieces of the general type disclosed in US Patent No. 4,152,742 issued to the Applicant. . It comprises a body of generally rectangular shape, the cores form read / write gaps and erasure on the transducer face, the rear branches of the pole pieces being oriented in a direction opposite to the body of the tiransducteur

  for the attachment of magnetic coils, wires and a back bar.

  The transducer 32 is fixed by gluing on the central portion 66 of the bending element, the body of the transducer being centered at the intersection of the X and Y axes and the transducer being oriented so that its air gap

  read / write has the correct orientation for data transfer.

  Openings 71 and 72 formed in the central portion 66 establish

  play for the back branches of the cores of the transducer assembly.

14 2466832

  With reference to FIGS. 3 and 4, coils 73, 74 of the transducer are placed

  on the branches that pass through the openings and above

  the bending element 65. The rear bar can then be put in place.

  The transducer 32 is thus mounted on the arm 35 as described above.

  above, the bending element 65 constitutes an elastic support allowing

  a rotation of the transducer around the X and Y axes, without hindering the function

magnetic effect of the transducer.

  Electrical connections between the transducer 32 and the system with which it is used are established by means of a connector panel 75 having eyelets 82, a flexible band 81 and a cable having a plurality of wires. The connector panel 75, formed of a phenolic resin, has a rectangular shape and is dimensioned so as to be placed on the side of the transducer 32, namely on a central portion 66 of the flexural element 65. It is provided along one side of the connector panel 75 a central notch 76, visible in Figure 2. The same edge of the connector panel 75 has an interrupted lip 77, extending downwards,

  as shown in Figure 9 and which passes through openings 78

  in the flexure member 65 to penetrate a notch 79 in the rear side of the transducer body 32. The connector panel 75

  is bonded to the central portion 66 of the bending element 65.

  The flexible strip 81 constitutes a printed circuit which is extremely interesting.

  which has a plurality of flat conductors 92 extending between a first end 93 arranged in correspondence with the dimensions of the connector panel 75 and a second end 94, where the conductors are widened to form terminals 95 on which the wires 88 are to be brazed . At the end 93

  of the flexible band, the conductors are provided with holes 96.

  The end 93 is placed on the connector panel 75 and eyelets 82 forming terminals are engaged in holes 96 so as to penetrate into the connector panel 75 without passing through it. The end 94 of the flexible cable 81 is engaged upwardly in a slot 97 in the body 96 and which opens into a recess 87. A lower transverse partition wall provided in the recess 87 has small longitudinal slots 91 to enter. in rubbing contact with the individual wires 88 of a cable

  to keep them in position. Terminals 95 are brazed on the ends

  mites 88 and the end 94 of the flexible cable 81 can be fixed

  by bonding in the recess 87, as indicated in 98.

  The wires 88 constitute the ends of a connection cable 80 which establishes a connection with the system (not shown) o the transducer assembly

2466832

  must be used. Intersecting passages 83, 84, 85, 86 are formed in the upper surface of the workpiece 52, looking at FIG. 2, so that the cable 80 can be moved from the arm 35 to the forward passage 83 and then

  from there, and through three alternate lanes, through

  intermediate passages 84, 85 or 86, to the carriages provided on either side or on the rear of the base 50, as necessary for use with a given design of the disk drive mechanism. In any case, the cable is held in place by the rear end of the spring 55 which is applied against the piece 52 so as to form

  the upper part of said passages.

  Preferably, the cable 83 has an insulating outer sheath that is cut approximately where it passes through the passageway 83. The inner wires 88, loosely twisted together, continue to pass below the spring 55 along. of the upper part of the body 36 to penetrate, through the recess 87, into the slots provided

  in the separating partition 90, as previously described.

  It has been found desirable to remove the outer sheath and the shield before the wires cross the blade hinge, so that the stiffness

  cable 80 does not hinder the bending of the blade hinge.

  By passing the cable and wires as described above, the electrical connections between the

  transducer head and the carriage, the cable and the wires being further pro-

  Protected against incidents such as tearing, jamming or rubbing by other components, both during assembly and during operation. This arrangement of the wires and cables is clearly preferable to that which has been adopted in the known embodiments, one

  Bonded the cable to the side of the arm, pedestal, and cart.

  The use of the connector panel 75, the eyelets 82 and the

  flexible band 81 greatly facilitates the process of-connection of the coils

  73, 74 with the wires of the cable 80 and with the external circuits.

  It should be noted that the son used in the coils 73, 74 are extremely fine and delicate. In known embodiments which do not include the connector panel 75 and the terminals 82, it was necessary to solder these delicate wires directly to terminals provided on a flexible strip,

  which was a difficult operation and what was causing a

  the flexible band because the wires had to be heated to a temperature high enough to cause

of their insulation.

  These disadvantages have been solved according to the present invention, firstly by simply winding the delicate wires from the coils 73, 74 around the appropriate eyelet 82, which holds them correctly in position. The terminals 82 can then be heated and the solder deposited to simultaneously ensure, on the one hand, the brazing of the wires on the eyelets and,

  on the other hand, the soldering of the eyelets on the flexible band.

  Since it does not interfere with a manual fixing or positioning operation

  During the brazing process, the latter operation can generally be carried out in the shortest possible time and the risk of damage to the windings of the coils or of the flexible band is also minimized, which could otherwise result in a short time. circuiting

  conductors of the flexible band. After the soldering operation, it is possible

  the excess length of the delicate threads.

  As further shown in Figure 2, the opening 60 provided in the body 36 of the arm can be closed by an independent piece nestable 120

  which has an upper portion 121 provided with a lifting lug 122.

  The walls of the opening 60 are slightly stripped, as indicated at 123 in FIG. 8, so as to receive several elastic locks 124 secured to the upper part 121 and which are directed downwards so as to engage in the zones stripped. In addition, a wall of the auxiliary part 120 is arranged in the form of a resilient element 125 which is intended to be applied against the body 36 near the place where the flexible band 81 passes into the slot 97. auxiliary piece 120 can be nested manually in place in the recess 60 so as to enter

  in contact with the flanges 61, 62, 63, these elastic latches 124 engage

  in the stripped portions 123 of the recess. The elastic element exerts a thrust against the rear edge of the opening 60 so as to stabilize the position of the auxiliary part 120 along the Y axis. This auxiliary part 120, which effectively constitutes a cover, can

  then be fixed in place permanently.

  The cover 120 is provided with numerous reinforcing ribs, as shown in FIGS. 7 and 8. One of these ribs, designated 130, comprises a central enlargement 131 in which is arranged a threaded hole 132 oriented obliquely through the cover of FIG. to receive a locking screw 133. As more clearly shown in Figure 9, the screw of

  fixation 133 is provided with a rounded or spherical tip 134.

  This fixing screw 133 is oriented at an angle so as to pass through the notch 76 formed in the connector panel 175 to bear against the upper surface of the flexure element 65,

  while simultaneously playing game for the reels.

17 2466832

  The point of contact between the fixing screw and the bending element is located

  at the intersection of the X and Y axes of the bending element 65 previously described.

  The tip of the fixing screw 133, positioned to make nominal contact with the bending member 65, constitutes a pivot point for the hinge movement along the XY axes of the transducer 32. The bending member 65 allows any combination of rotational motions about the X and Y axes, so that the transducer face can adapt to the plane of the lower transducer during a data transfer operation. However, no movement of the bending element is allowed in a direction oriented perpendicularly upwards from the

  surface of the disc but, on the contrary, forces oriented in this direc-

  are transmitted to the arm via the transducer, the screw

  133 and the cover 120. Similarly, the force applied to the transducers

  32 and 33 for correct contact with the flexible disk is trans-

  transducer 32 from the spring 55 and through the

  body 36 of the arm, the cover 120 and the fixing screw 133.

  The use of the nestable lid 120 provides a number of advantages in the manufacture of the transducer assemblies. Firstly,

  an opening in the upper part of the arm 35 is provided before the in-

  120 of the cover, which greatly facilitates the assembly of the coils, the rear bar and the connector panel, and the connection phases of the coil son with the eyelets. In addition, since the fixing screw 133 is provided in the cover 120, there is no pin pivoting inside the arm near the coils of the transducers,

  as in the known embodiments, which further facilitates assembly.

  Another advantage is that different lids 120, having lifting lugs 122 of different shapes and profiles, can

  used to meet the requirements of different manufacturers.

  cants, which allows the realization of an arm corresponding to a single

basic structure.

  Although, in the preferred embodiment, a screw of

  133 to form the pivot point of the joint of the trans-

  the upper die, it is possible, on the contrary, to use a pin whose position can be adjusted, or to provide an attached pin which is fixed to the molding in the cover 120. However, to obtain a greater accuracy of adjustment, it is better to use the screw of

  fixing 133 or the adjustable spindle.

18 -2466832

  The fixing screw 133 is adjusted, while the cover 120 is in place in the arm, so that its tip, which effectively forms the pivot point, is just-level with the base surface 41 of the arm 35; in other words, adjustment of the screw 133 is made until it comes into contact with the surface of the bending element 65 which is then in its non-inflected condition. This operation can be carried out in the best possible way by controlling the electrical continuity existing between the fixing screw and the bending element being adjusted. The adjustable fastening screw 133, or an adjustable pin, has advantages over a pivot which is formed from a plastic protrusion existing within the arm, as in known embodiments. A plastic swivel tip tends to wear out, and over time the formation of a flattened area

  a lower quality pivot than a hard and rounded pivot.

  In addition, there are difficulties in accurately positioning a molded plastic pivot point, while an adjustable pivot, such as the fixing screw 133 or an adjustable pin, can be optimally set in the correct position. If the pivot point is set too high, or is too far away from the bending element, the transducer bounces excessively during loading. On the contrary, if the pivot point is set too low, the bending element

is deformed.

  Figure 9 shows in more detail the positional relationship between the upper transducer 32 and the lower transducer 33, in the service condition where they are in contact with the flexible disk 20. The transducer

  33 is part of a lower transducer head assembly comprising

  as a base in the form of an octagonal nut, what is called in the industrial field a "button-shaped head". The lower head support comprises an outer carrier casing 150 made of a molded plastic and having an upper annular portion 151 of conical shape or

  bevelled, which surrounds a circular plate 152, generally plane.

  As mentioned earlier, the lower transducer may be of a type

  known, where the transducer is fixed immovably in the housing.

  However, it is preferable to use a transducer 33 having a Z-axis suspension as claimed in the aforementioned patent application. The transducer 33 can then execute a limited degree of motion

  along the Z axis, which is perpendicular to the nominal plane of the disk.

19 2466832

  The sliding transducers 32, 33, apart from their particular suspension and their supporting structure are preferably identical. This provides a

  profitability because of the simplicity and ease of manufacture

  cation and, in addition, a functional advantage is obtained because the areas of contact with the upper face and the lower face of the flexible disc

have the same dimensions.

  When designing "button-shaped" head transducers for single-sided active-duty discs, it is conventional to provide a

  transducer which is level with the crankcase, but the face of the trans-

  ductor is curved and enters the nominal plane of the disc in order to

  blir a good contact. It is not practical to use a curved face of

  transducer in a system operating on both sides of the disk.

  It is therefore preferable in systems operating on both

  the faces of the flexible disc, to provide flat-face transducers for ob-

  maintain correct opposite areas of mutual contact with the disc.

  The plastic body of the housing 150 must not be able to come into contact with the surface of the flexible disk because the nature of the plastic material is such that it would scrape off the oxide coating, and consequently its wear, even though this plastic was initially polished. The known double-sided transducer assembly of US Pat. No. 4,151,573 mentioned above employs a lower transducer which, in addition to being immovably attached in the housing, has a large shoulder area made of a ceramic material and surrounding the flat portion of the surface which contains the air gap, said shoulder area being rounded to join the body of the housing. This large shoulder area of ceramic material is necessary for the plastic housing to not come into contact

with the floppy disk.

  It has been found advantageous to use a smaller, generally rectangular-shaped lower transducer which protrudes beyond the lower casing plate 152, unlike the type of structure described above. This makes it possible to reduce the cost of the lower transducer since, with the exception of the finishing operation, it can be realized with

  identical to the upper transducer.

  The lower transducer 33 protruding above the surface

  152 of the lower case, ramps 160 and 161 have been provided to guide the flexible disk during its insertion and removal, in order to protect the transducer and to facilitate the entry and

output of the disc.

20.2466832

  The ramps 160 and 161 are integral with the plate 152 and they extend beyond

  above it, on either side of the position of the transducer 32.

  If necessary, as in the case of the aforementioned patent application and concerning a Z-axis flexible suspension, the ramps 160 and 161 may be forked, or they may be divided in their longitudinal direction.

  pendicular to the plane of FIG. 9 to provide an interval for the

pension of the lower head.

  During the process of inserting a floppy disk or "diskette" into the head assembly, the upper arm 35 performs upward pivotal movement around the blade hinge indicated in Figure 13 and under the action a lifting solenoid, or other mechanism (not shown) that contacts the lifting lug. As the flexible disk is moved within the head assembly in the direction indicated by the arrow 165 in FIG. 13, the front edge of the envelope 21 contacts the ramp 160 and rises along this one. As also shown in detail in Figure 12, there is provided a bevel 153 along the edge of the ramp 160 adjacent to the transducer

  lower part, this bevel also helping to guide the enven-

  lopped above the surface of the transducer and transversely to it.

  The upper part of the ramp 160 is located at a higher level than the beginning of the bevel 153 to ensure that the flexible disk does not come into contact with the transducer side. Once the floppy disk is in place, the arm can be released for the application of the heads on the

  flexible disk through the access openings.

  For the removal of the flexible disk, the arm 35 is raised again and the envelope is moved in the opposite direction. At this time, the ramp 161, and the adjacent bevelled edge 154 placed on the other side of the lower transducer, then provide the important function of guiding the envelope 21 of the flexible disk. The portion of the casing 21 at the end 24 of the slot contacts and moves upward on the ramp 161 and

  on the beveled side 154 of the transducer, transversely thereto.

  The ramp 161 therefore prevents, in cooperation with the bevelled edge of the transducer, an entry into contact with the end of the envelope 162, or the end of the access slot 24 of this envelope, with the side of the transducer, and therefore the application of forces to the latter

  during the insertion or removal operation of a floppy disk.

  It has been common practice to bevel the edges adjacent to planar profile transducer faces. This was done by forming a bevel of about 220 relative to the plane of the face on each of the four edges delimiting this face. The bevel is often rounded to a slight radius by polishing, in the area where it joins the face, so that there is no discontinuity or sharp edge that would tend to tear and use

  excessively the recording medium passing in front of the head.

  The transducer corresponding to the preferred embodiment comprises such a bevel but, in addition, there is provided a large bevelling of the corners of the transducers. It was found that the greatest degree of wear of the disc surface did not occur during uniform movement of the disc in front of the transducer when accessing the functional position of the disc.

  transfer of data but during the loading and unloading

  ment. It has been found that in known systems excessive wear is caused on the disc by the corners of the transducer when the upper arm

  down to apply the corresponding transducer on the disc.

  A somewhat similar wear problem arises during unloading as a result of raising the arm in an eccentric condition, which results in friction on one or both corners of the transducer. If the legs of the transducer were perfectly parallel to each other at the time of

  contact with the disc being loaded, and if the disc was

  plane without any undulation or deformation, the corners of the trans-

  ductors located in areas adjacent to the faces of the disk would not

  no problem. However, in practice, there is a certain degree of non-

  parallelism, because of the inevitable manufacturing tolerances and also because the "free" or "neutral" position of the bending element 65 does not

  not necessarily keep the transducer 32 parallel to the disk.

  This means in practice that the upper transducer is not oriented, at the time of impact with the disk, parallel to the disk or at the

  face of the lower transducer, this being due to some combination

  The result is that there is a corner of the transducer that first contacts the disk, concentrating the impact force on a small

  area and nicking the oxide layer.

  To minimize these difficulties, bevelled corners and edges adjacent to the transducer faces as shown in the drawings. The faces of the upper and lower transducers have been shown respectively in Figures 10 and 11. Edge beveling is performed on the lower transducer 33, as indicated by numerals 153, 154, 155, and 156 in Figure 11. Beveling performed on the edges 153 and 154 is 300, to facilitate the guiding action of the flexible disk during the insertion and removal operations,

as previously described.

22 2466832

  For convenience, the beveling made on the edges 155 and 156 may be identical. These beveled edges would cut into the corners leaving a sharp edge which, while being inclined in a direction opposite to the disc, would still cause a concentration of stresses, risking to grooves or cuts in the surface of the disc when of the contacting of the transducer with the latter. These edges are eliminated by conical bevels 157 provided in each corner and which join the edge bevels 153-156. In addition, all edge and corner bevels are rounded and tangentially joined to the transducer face during a final polishing operation to remove sharp edges.

  and discontinuities on the corresponding face of the transducer.

  The upper transducer 32 is provided in the same manner with edge bevels 140-143, which are inclined preferably 150, and bevels

  corners 144. Again all bevels are rounded and gradually join

  the corresponding face to remove all sharp edges.

  The bevel of 150 is adopted preferentially for the upper transducer because it allows to widen the wedge bevel to better distribute the impact forces. However, the bevel of 30 is adopted preferentially for the lower transducer for its cooperation with the ramps 160

  and 161, as previously described.

  Of course, the present invention is not limited to the embodiments described and shown; it is capable of numerous variants accessible to those skilled in the art, depending on the applications envisaged and without

  we do not deviate from the spirit of the invention.

232466832

Claims (24)

  1. Transducer-arm assembly for use with an active double-sided flexible disk, characterized in that it comprises in combination: an elongated body (36) having first and second opposite faces and provided with an opening passing through it; near a first end and between said faces; - a hinge (43) provided at the second end of said body (36) so as to connect the latter to a carrier member;   a substantially planar bending element (65) comprising a central part   recessed and profiled tread so as to allow pivoting movement of said central portion about axes (X, Y) mutually perpendicular and normally located in the plane of said element (65); a transducer (32) mounted on said bending element so as to partially engage said openings; means (64) for securing the bending member (65) to a face of said arm (35) so as to extend transversely to said opening therein; and a cover (120) for closing off the opening in the arm on its second side, said cover having a lifting tab (122) positioned to project laterally from the arm, and a pivot (133) positioned to enter said opening to make contact   with the bending element (65) at the point of intersection of said axes (X, Y).   2. An assembly according to claim 1, characterized in that said pivot   (133) is adjustable in a direction having at least one component   pendicular to the plane of said bending element (65).   3.- assembly according to claim 2, characterized in that said pivot (133) is constituted by a fixing screw which is screwed through said cover (120).   4. An assembly according to claim 1, characterized in that said cou-   vercle (120) comprises an independent piece profiled corresponding to the-   said opening in the body (36) to determine the position   said pivot (133) with respect to the bending element (65).   5. Transducer-arm assembly, usable with an active double-sided flexible disk and characterized in that it comprises in combination: an elongated body (36) having first and second opposite faces and provided with an opening located at near a first end; a transducer (32) mounted in said opening so as to be pivotable thereto; a hinge (43) provided at the second end of said body (36) so as to ensure the connection of said assembly with a support, said hinge (43)   having an elastic blade (44) projecting from said second former   tremity and locking means (42-47, 52, 53), which are provided with   wise in their surface remote from said elastic blade, for guiding electrical conductors to said transducer; - and a thrust spring (55) having a first end which is applied against said body (36) at a point spaced from its second end, and further a second end which is fixed on said surface of the locking means (69) and which covers the passages In this one.   6. An assembly according to claim 5, characterized in that said   hinge (43) is removably attached to said body (36).   7. The assembly of claim 5, characterized in that said locking means comprises a plurality of intersecting passages (42-47, 52, 53) and supplemented by said biasing spring (55) so as to guide a cable (80). with multiple conductors to the body (36) and in that said body (36)   includes parts for frictionally retaining individual conductors   said cable for connection to said transducer (32).   8. Transducer-arm assembly usable with an active double-sided disc, characterized in that it comprises in combination: an elongated body (36) having first and second opposing faces and provided with an opening through it to near a first end and between said faces; a hinge (43) placed at the second end of said body (36) so as to ensure its connection with a support;   a substantially planar bending element (65) comprising a central part   recessed and profiled tread so as to allow pivotal movement of said central portion about axes (X, Y), mutually perpendicular and normally located in the plane of said element (65); a transducer (32) mounted on said bending element (65) so as to partially penetrate into said openings therein, said transducer having a working face located on one side of the bending member and windings (73, 74) on the other side of said bending member (65); means (64) for fixing the bending element (65) on one side of said arm (35) so that said windings (73, 74) are located in the opening in said arm; conductors (92) extending along said body (36) so as to make connections with an external system; - a connector panel (75) fixed on said other side of the bending element (65) in an area adjacent to said windings (73, 74); and terminals (82) provided on the panel (75) for selectively connecting said windings (73, 74) and said conductors (92) for   to establish interconnections between them.   9. An assembly according to claim 8, characterized in that said   conductors include the conductors of an associated printed circuit board.   10. An assembly according to claim 8, characterized in that said terminals comprise eyelets (82) arranged to allow the ends   wires (88) of said windings (73, 74) being wound around.   11. An assembly according to claim 9, characterized in that said printed circuit is placed on the connector panel (75) so that said eyelets (82) pass through areas of the conductors printed on the circuit, and in that   the eyelets (82) are arranged to allow the ends of said wraps to   to be wrapped around, allowing the positioning of the conductors   (92) and wires (88) for simultaneous brazing on said eyelets (82).   Magnetic transducer for use in a magnetic disk data storage system, characterized in that it comprises cores and ceramic parts which are fixed together to form a transducer body (36) provided with a plane face ( 41) in which is positioned an air gap for cooperating by contact with a disk-shaped recording medium (20) in data transfer operations, the edges of the transducer body which are adjacent to said face being beveled (153). , 154), and   the corners (155, 156) provided at the intersections of the adjacent edges being likewise   beveled, eliminating stress concentrations on the   recording medium in the case of contact with the corresponding corner.   laying the transducer with the recording medium during operations   loading or unloading the transducer.   13. Magnetic transducer according to claim 12, characterized in that bevels of conical section are formed on said corners so as to   join the beveling edges located on both sides of said corner.   14. Magnetic transducer according to claim 12 or 13, characterized in that the edge and wedge bevels (153, 154, 155, 156) are rounded off by filleting to join the flat face of the transducer (33) in order to 'to avoid superficial discontinuities. 26 246683 2   15.- set of transducers usable with flexible discs with double active face, characterized in that it comprises: - a first and a second transducer (32, 33) each carrying a body (36) provided with a flat face in - which is provided a gap of reading / writing; means (35,36) supporting the first and second transducers so as to enable its movement into a data transfer functional position in which the faces of said first and second transducers (32,33) are placed in mutually opposed positions contacting opposite sides of said flexible disk (20);   in that said first and second transducers comprise bi-directional edges   (153, 154) in areas adjacent to said planar faces and   carry beveled corners (155, 156) at intersections of the edges adjacent to said planar faces so as to avoid stress concentrations on the recording medium (20) in the case of contact with the corresponding corner of a body of transducer with recording medium during loading or unloading of transducers with respect to said recording medium.   16. A set of transducers according to claim 15, characterized in that the edge and wedge bevels (153-156) are rounded or provided with   of a fillet so as to join the flat faces of the transducer.   17. A set of transducers according to claim 16, characterized in that bevels of conical section (157) are formed on said corners so as to join the bevel of edges (153-154) provided on both sides corners.   18. A set of transducers according to claim 16, characterized in that one of the transducers (33) comprises edge and wedge bevels (153-156) making an inclination angle of about 300 with respect to its face. plane, and in that the other transducer (32) has edge and corner bevels (140-144) at an angle of about 15 to its planar face. 19.- Transducer support arm articulated on an elastic blade and intended to be connected to a mobile transducer support carriage in a set of magnetic transducers operating on the two active faces of a flexible disk, characterized in that it comprises a thin flexible hinge (43) with a blade; an elongate support arm (35) comprising means for mounting a magnetic transducer in an area adjacent to one end of the arm, 27 2466832   for contacting a recording medium (20) in a service position, said carrier arm (35) having a surface of   generally flat configuration in an area adjacent to the recording medium   registering in the service position, and being provided in said flat surface with a recessed portion in a position adjacent to the end of the arm which is remote from said transducer; - a first locking plate (50), profiled so as to be received in the recessed portion of said arm; a second blocking plate (52);   means for connecting the blocking plates to opposite surfaces;   one end of said blade hinge, to also provide the connection of said hinge and said locking plates with said   arm when the first locking plate is positioned in said recess   in that said first and second plates of. block (50, 52) have opposed straight edges (58) cooperatively defining   a bending axis of said blade hinge.   20.- Device according to claim 19, characterized in that said first and second locking plates (50, 52) and said recess are profiled so that, in the assembly condition, the outer surface of said second blocking plate (52) is generally coplanar with said surface plane of said arm (35). -   21.- Device according to claim 20, characterized in that said locking plates (50, 52) are spot-welded on said blade hinge along said opposite rectilinear edges (58) and in an adjacent zone at said edges.   22.- Magnetic transducer assembly usable in a magnetic disk data storage system, characterized in that it comprises: - a magnetic transducer (32) provided with a flat face; a housing for said transducer; means (35, 44) for positioning. the transducer in said housing so that its protruding side thereof contacts the disk-shaped recording medium (20) to provide data transfer; and a guide ramp (160) positioned on said housing so as to be inclined toward the transducer (32) for guiding the edge of a flexible disk-shaped recording medium (20) on the face of the transducer when inserting said disk into a service position relative to the transducer (32). 28 2466832   23. A magnetic transducer assembly according to claim 22, characterized   characterized in that it further comprises a second guide ramp (161) located on the side of the transducer (32) which is opposite to the first guide ramp (160), and inclined towards the transducer (32) so as to guiding a disk-shaped recording medium (20) to the transducer (32) when said disk is removed from its service position   with respect to said transducer (32).   24.- A magnetic transducer assembly according to claim 22 or 23, characterized in that it further comprises bevels (155, 156) provided on the edges of said transducer which are adjacent to said ramp (161) in view   to further improve the guidance of the recording disk.