Patent Abstract:
A magnetic head is provided for use with magnetic recording media of varying stiffness. The head includes a first and a second elongated support spaced apart on a facing surface with support surfaces extending along a longitudinal axis. A core support is positioned between the two elongated supports and is wider than the support surfaces to distribute tape contact pressures. The core support includes a transducer core with an elongated contact surface positioned to extend transverse to the longitudinal axis of the support surfaces. An edge member is positioned adjacent the contact surface of the transducer core to control wear and direct airflow. The edge member includes a wear surface of a material with greater wear resistance than the transducer core. A second edge member is provided on the opposite side of the contact surface of the transducer core to accommodate multi-direction tape travel.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates, in general, to magnetic tape head assemblies for use in conjunction with magnetic contact recording media, and more particularly to a tape head with a transducer support assembly with protective edges, i.e., at the leading and trailing edges, adjacent the core to create an increased height or radius adjacent the core and read/write gap to enhance air removal and to provide wear protection for the softer core materials during high speed operations with a number of recording media or tape having varying stiffness. 
     2. Relevant Background 
     Magnetic head assemblies typically contain one or more raised strips or supports that have surfaces over which the magnetic recording media, e.g., tape, passes. Embedded in each support surface is a transducer which may be a recording transducer (i.e. recording or writing head) for writing information (i.e., bits of data) onto the media or a reproducing transducer (i.e., reproducing or reading head) for reading information from the media. An embedded recording transducer produces a magnetic field in the vicinity of a small gap in the core of the recording transducer that causes information to be stored on the magnetic media as it streams across the support surface. In contrast, a reproducing transducer detects a magnetic field near the surface of the magnetic media in the vicinity of a small gap as the media streams over the support surface. 
     There is typically some microscopic separation between the gap of the transducer core and the recording media. During operation, this separation must be tightly monitored and controlled to avoid or minimize “spacing loss.” The separation reduces the magnetic field coupling between the recording transducer and the media during writing and between the media and the reproducing transducer during reading. The magnetic field coupling decreases exponentially both with respect to increases in the separation between the media and the support and with respect to increases in the recording density. The amount of media area required to store a bit of data is a factor in determining recording density and as less media area is required to store a bit of data, the recording density increases. Thus, while a higher, more easily obtainable amount of head-to-media separation may be acceptable at low recording densities, the growing demand for higher recording densities has led to the need for tighter control over the head-to-media separation that can be tolerated to obtain useful levels of magnetic coupling. 
     To control spacing loss, a tension is applied to the tape as the tape passes at a wrap angle around a support surface and an adjacent transducer core surface each having a height and a width. Due to this tension, the tape exerts a pressure against the support surface, and if the support surface and core surface have uniform widths and heights, the pressure is substantially uniform along a longitudinal axis of the support. The pressure is essentially proportional to the tension and the wrap angle and inversely proportional to the support width. 
     In some tape head assembly designs, the pressure is intentionally increased to control spacing loss. For example, the pressure can be increased by increasing the tension in the tape, by modifying the wrap angle of the tape on the support surface, and/or by modifying the width of the support surface. However, increased pressure is accompanied by negative consequences including reduced tape life, increased possibility of tape damage and data loss, and support and core surface wear leading to a shortened head life. Moreover, increased pressure can result in uneven wear along the support surface, which can be particularly troublesome between regions of the support and the transducer core. As can be appreciated, increased and uneven wear rates become more serious problems as operational speeds for magnetic head assemblies are increased. 
     Operational problems with head wear and uneven wear have recently grown with the use of magnetic media having varying stiffness. For example, a magnetic head assembly may be used to read and write to a magnetic tape with a given stiffness that causes the magnetic tape to have a corresponding natural radius and contours. The support surfaces and core typically will wear to fit better this radius and natural contours of the tape. When the magnetic head assembly is then used with a magnetic tape having a different stiffness, e.g., a higher stiffness tape, a larger and sometimes unacceptable separation distance may initially exist until again the magnetic media is worn or broken in to match the new tape stiffness. Hence, there is a need for a magnetic head assembly that address the need for wear control that is also useful for magnetic media of varying stiffness. 
     Several magnetic head assembly designs have been developed in attempt to address these wear problems. In many tape head assembly designs, the pressure at the core is increased to enhance magnetic coupling by providing an elongated support assembly in which the width of the core and adjacent surfaces is less than the width of the adjacent elongated support surfaces. This smaller width makes the pressure applied non-uniform along the longitudinal axis of the support with higher pressure being applied at the core area and providing a better contact area. Unfortunately, this head design often results in higher wear rates at the core area that may lead to uneven wear within the support assembly. In some cases, higher core wear rates and pressures have been addressed with the use of wear resistant materials for the core center and/or in the adjacent supporting surfaces that are either parallel to the travel path of the media over the core or on all sides of the core. 
     In a different design approach, the support area near the core is made wider than the adjacent elongated support surfaces to obtain a softer or lower pressure mating of core and magnetic media. Wider core area designs are described in detail in U.S. Pat. Nos. 5,426,551 and 5,475,533 to Saliba, which are both incorporated herein by reference. The wider support surface near the core results in less pressure being applied at the core which is beneficial in controlling uneven wear. The wear rate is further controlled by providing wear surfaces of glass or other nonmagnetic material adjacent the magnetic ferrite core positioned parallel to the travel path of magnetic media. The wear rate is self-regulated to be relatively uniform along the longitudinal axis of the support assembly because the pressure is less than on the elongated support surfaces that are fabricated of a more wear resistant material. While addressing some industry problems, these wider core area devices tend to function well initially but then also develop problems of uneven wear on support surfaces and of core wear as the entire support assembly experiences wear. Additionally, the height of the core and adjacent wear surfaces typically are selected for a particular media and media thickness and experience wear that makes the device better suited for continued use with that media rather than for several media with varying stiffnesses. 
     Additionally, air flowing under the magnetic media during higher speed operations can cause spacing losses, and airflow needs to be addressed during magnetic head assembly design. During operation, air is moved within the magnetic head assembly as the magnetic media rapidly advances across the surfaces of the assembly facing and supporting the magnetic media, such as the support surface and the core. Spacing losses can develop when the flowing air passes between the core and read/write gap and the magnetic media. In the narrower core area devices, air tends to be channeled over the core because it first strikes the wider adjoining support surfaces and then is forced into the narrower core area. The wider core area devices provide better airflow control with the air first striking the wider core area and being channeled away towards the adjacent, narrower support areas where reading and/or writing is not occurring. However, for both types of head assemblies, the use of numerous magnetic media with differing stiffness often results in airflow problems that result in spacing losses. Also, over the lifetime of the head assemblies, wear (and particularly, uneven wear) often results in changing airflow paths that can lead to airflow problems even in devices that initially functioned effectively. 
     Hence, there remains a need for a magnetic head assembly that better controls airflow over a magnetic core and provides enhanced wear control in surfaces contacting the magnetic media, which may have varying stiffness. 
     SUMMARY OF THE INVENTION 
     The present invention addresses the above discussed and additional problems by providing a wider core area design for a transducer support assembly that controls uneven wear problems while also providing improved airflow control to limit spacing losses (e.g., to minimize “floating” separation). The inventor recognizes that the use of a wider core area relative to narrower adjacent, elongated support surfaces often results in the contact pressure applied by the media, e.g., magnetic recording tape, being concentrated at the edges of the wider core area, i.e., core support. Hence, as the tape passes over the transducer support assembly, the edges (note, both edges act as leading and trailing edges depending on the direction of travel of the media) are worn down at a faster rate, which can cause airflow problems and spacing losses. 
     To address this problem that is generally unique to wider core area designs in tape head assemblies, the core support is initially manufactured to include wear surfaces of a harder, more wear-resistant material at the two leading/trailing edges to extend the useable life of tape head assemblies. In a preferred embodiment, the wear-resistant edge members are raised (or, alternatively, the edge members may initially be coplanar with softer adjacent wear surfaces and allowed to become raised due to wear occurring in an initial break-in wear period) to provide a larger height than the core. After a break in or initial wear period the edge members and core contact surfaces become generally arcuate in cross-section with the initially larger radius of the edge members controlling wear on core. In operation, the arcuate surfaces typically form a single continuous curved surface with a single radius that contacts the recording media. Having an edge member that always has a larger or equal radius to the adjacent core surface is especially beneficial for high speed operations as it better directs airflow (e.g., strips away air being moved with the tape from the core area) and protects the transducer core from wear. 
     More particularly, a magnetic head is provided for writing to and reading from magnetic recording media, such as tapes of varying stiffness. The head includes first and second elongated supports spaced apart on a facing surface and having support surfaces extending along a longitudinal axis. During operation, the magnetic recording media travels transversely across the support surfaces applying a contact pressure. A core support is positioned between the two elongated supports. The core support has a width as measured perpendicularly to the longitudinal axis of the support surfaces that is greater than the widths of the support surfaces thus creating a nonuniform pressure distribution along the longitudinal axis (e.g., when contact surfaces are coplanar or the same radius, greater pressure is applied on the narrower support surfaces). 
     The core support includes a transducer core with an elongated contact surface positioned to extend transverse to the longitudinal axis of the support surfaces. An edge member is positioned adjacent the contact surface of the transducer core to control wear and direct airflow. In this regard, the edge member includes a wear surface for contacting the media that is fabricated of a material, such as aluminum titanium carbide or zirconium, that is harder and has a greater wear resistance than the transducer core. In a preferred embodiment, a second edge member is provided on the opposite side of the contact surface of the transducer core to accommodate multiple tape travel directions. After initial fabrication, the wear surfaces of the edge members are substantially coplanar and raised relative to the contact surface of the transducer core and the support surfaces. Additionally, the contact surface itself may be raised relative to the support surfaces with these two surfaces have similar hardness and wear resistance characteristics (e.g., both surfaces may be magnetic ferrite or the like). In this manner, the magnetic head provides self-regulating wear regions that adjust to distribute the contact pressure and wear such that the wear surfaces of the edge members are generally raised relative to the contact surface of the transducer core and the support surfaces. 
     After break in and during the operational life of the head, the wear surfaces of the edge members are arcuate with a radius that is larger than the adjacent wear surfaces. In this fashion, the edge members control the contact with the magnetic media and the rate of wear in the adjacent protected core area. The contact surface of the core that was initially lower than the wear surfaces of the edge members eventually becomes arcuate and has a radius that is substantially equal to or slightly less than the wear surfaces of the edge members. The contact surface of the core and the wear surfaces of the edge members generally form a continuous contact surface that is raised (or at a larger radius) than the adjacent elongated supports to provide good coupling and contact with the recording media. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a linear tape head assembly in which the principles of the present invention are particularly suited. 
     FIG. 2 is an illustration of the linear tape head assembly of FIG. 1 during operation showing the positioning and movement of a magnetic media, i.e., a magnetic recording tape, relative to tape facing surfaces and to three elongated transducer support assemblies. 
     FIG. 3 is an enlarged perspective view of one embodiment of a transducer core for use with the tape head assembly of FIG. 1 showing the read/write gap. 
     FIG. 4 is an enlarged partial view one of the transducer support assemblies of FIG. 1 illustrating the use of two elongated supports to sandwich and support a core support having raised, wear-resistant edge members according to a significant feature of the invention. 
     FIG. 5 is an end elevation view of the transducer support assembly of FIG. 4 showing a preferred embodiment in which the height of the wear-resistant edge members is greater than the height of the wear surface of the nonmagnetic support member adjacent the transducer core and the height of the support surfaces of the elongated supports. 
     FIG. 6 is a view of the transducer support assembly after an initial break in period illustrating the relative radii of the contact surfaces that is substantially retained for the operational life of the assembly. 
     FIG. 7 is a side view of the assembly of FIG. 6 illustrating that edge member surface areas, the nonmagnetic support member surface areas, and the core form a substantially continuous curved surface with a single radius suited to the critical radius of the recording medium. 
     FIG. 8 is a view similar to FIG. 4 showing an alternate embodiment of a core support in which raised, wear-resistant edge members are curved to enhance aerodynamic features of the transducer support assembly. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides the features of enhanced airflow control and media contact surface wear control by providing a unique transducer support assembly. The assembly utilizes a pair of edge members (leading or trailing depending on travel direction of the magnetic media) in a wider core support design. The wear surfaces of the edge members are fabricated from a wear-resistant material, such as aluminum titanium carbide (ALTC) or zirconium, that is harder than the adjacent nonmagnetic support member (e.g., glass, ceramic material, and the like) and transducer core (e.g., ferrite such as single crystal ferrite or metal in gap ferrite (MIG)). The wear surfaces of the edge members may be configured to be initially raised relative to the nonmagnetic support member, transducer core, and elongated supports or facing members or due to the higher relative hardness, the edge members may become relatively raised due to uneven initial wear rates during operation. The raised leading and trailing edges provides improved air control as it blocks or redirects flowing air from passing over the transducer core and gap and ensures that the radius (e.g., height) of the transducer core remains greater than the critical or natural radius of the magnetic medium. 
     The invention is described in the following discussion as being particularly useful as part of a linear tape head assembly for use in a magnetic tape head assembly with transducer elements that are ferrite cores. However, those skilled in the art will understand that the transducer element or core may be a core inductive head, a magneto resistive read element, a thin film gap head, and other types of transducer elements in which it is useful to protect the core and gap from wear and airflow and to control the radius or height of the transducer element to manage spacing losses. Additionally, the magnetic media discussed for use with the invention is magnetic recording tape of varying stiffness, but the invention may be useful with other media such as contact hard disks, floppy disks, and the like. 
     Referring now to FIGS. 1 and 2, a linear tape head assembly  20  according to the invention is shown for use in writing to and reading from a magnetic recording tape  28 . The head assembly  20  includes tape facing surfaces  22  and three transducer support assemblies  24  for contacting and supporting the tape  28  as it moves in either direction shown by arrow  32 . In this manner, the transducer support assemblies  24  provide wear surfaces for the assembly  20 . The tape  28  is at a selectable tension that causes the tape  28  to apply a contact pressure on the transducer support assemblies  24  during reading and writing operations of the linear tape head assembly  20 . The transducer support assemblies  24  as shown include a pair of transducer cores  26  (as best seen in FIG. 3) for providing read and write functions of the assembly  20 . 
     The linear tape head assembly  20  is provided by way of example, and it should be understood that other types of tape head assemblies may be configured to include the transducer support assembly  24  of the present invention. For example, a helical tape drive assembly (not shown) may be designed with a rotating magnetic tape head that includes the transducer support assembly  24  and core(s)  26 . In this embodiment, the rotating magnetic tape head records information in helical form on a magnetic media (such as a tape  28 ) and reproduces information from the helical form stored on the magnetic media. The transducer support assembly  24  of the present invention will now be discussed in conjunction with the linear tape head assembly  20  using a ferrite core. However, the core support and transducer support assembly of the present invention may be used with other types of transducer elements (not shown). 
     Referring to FIG. 3, a typical core  26  (e.g., a magnetic ferrite core such as a single crystal ferrite) is shown. The core  26  has a gap  38 . The core  26  typically is one element in a transducer (not shown) that may be a recording transducer or a reproducing transducer. Each recording transducer provides a magnetic field in the vicinity of the gap  38  in the surface of the core  26 . Each reproducing transducer detects a magnetic field near the surface of the magnetic tape  28  in the vicinity of the gap  38 . The gap  38  has a gap length, G L , a gap width, G W , and a gap height, G H  (which is often referred to as the pole tip height and is defined by the poles  34 ). The gap width, G W , is generally equal to the width of a track on the tape  28 , i.e., the tape track width, which is often about two milliinches. The gap length, G L , may be varied to provide desired read and write functionality, and in one embodiment, is about ten microinches. 
     According to an important feature of the invention, the tape head assembly  20  includes a transducer support assembly  24  that provides enhanced airflow control and wear resistance. Referring to FIG. 4, an enlarged view of a representative portion  30  of one embodiment of the transducer support assembly  24  of FIG. 1 is illustrated as it would appear after initial fabrication (i.e., before a break in period or extended use). As shown, the transducer support assembly  24  includes the core  26  that is supported within a core support  50 , which is itself sandwiched between elongated support  40  and elongated support  44 . The elongated supports  40 ,  44  include planar support or facing surfaces  42 ,  48 , respectively, for contacting the tape  28  and providing wear surfaces for the transducer support assembly  24 . In a preferred embodiment, the elongated supports  40 ,  44  are fabricated from the same material as the core  26 , such as a ferrite. However, other types of magnetic material such as nickel zinc, magnesium zinc, and other well-known materials may be used for the support surfaces  42 ,  48  to provide wear resistance. The support surfaces  42 ,  48  are raised relative to the tape facing surfaces  22  of the head assembly  20  to a first height, H 1 , and have a support width, W S , for providing a contacting surface with the tape  28  during operations. 
     The core support  50  of the transducer support assembly  24  provides the significant structural features that provide the necessary magnetic coupling between the transducer core  26  and the tape  28 . As discussed previously, the core support  50  is designed to strip air away from the rapidly moving tape  28  to control floating or lifting of the tape  28  away from the core  26  and minimize spacing losses during read/write operations. Additionally, the core support  50  is configured to be useful with different magnetic media, such as tapes, that have differing stiffnesses, which cause the tapes to be wrapped on the head assembly at different radii and/or contours. Significantly, the structural features of the core support  50  are selected such that the most wear resistant features are always as high or higher relative to the facing surfaces  22  than the softer core and wear surfaces. In this manner, the core support  50  can be thought of as creating a larger, wear resistant radius that is suited for nearly any tape stiffness and tension, e.g., from the lowest stiffness tape to the highest stiffness tape utilized as a magnetic media. 
     Turning to FIGS. 4 and 5, the core support  50  illustrated includes a pair of wear-resistant edge members  54  and  58  with wear surfaces  56  and  60 , respectively, that contact the tape  28 . The edge members  54 ,  58  are positioned at each end of the core  26  such that the tape  28  contacts the edge members  54 ,  58  in either direction of movement (as shown by arrow  32  in FIG.  2 ). In one embodiment, the core  26  is secured within the core support  50  with a nonmagnetic support member  64  that has wear surfaces  66 . The nonmagnetic support member  64  may be fabricated from numerous nonmagnetic materials including many ceramics and glasses. In one embodiment, the nonmagnetic support member  64  comprises calcium titinate, nonmagnetic ferrite, or barium titinate. 
     Importantly, the edge members  54 ,  58  are fabricated from a material that is more wear resistant than the adjacent core  26 , the wear surface  66  of the nonmagnetic support  64 , and the support surfaces  42 ,  48  of the elongated supports  40 ,  44 . This results in the wear-resistant edge members  54 ,  58  wearing at a lower rate than the other wear and support surfaces  26 ,  66 ,  42 , and  48  when a relatively uniform pressure or wearing force is applied by the tape  28 . When the contact pressure is more concentrated at the raised edge members  54 ,  58  the wear rate along the transducer support assembly  24  is more uniform. A number of wear resistant materials may be utilized with the key consideration being that the selected material provide a wear rate that is lower than the other surface materials at a similar contact pressure or wearing force. In one embodiment, the edge members  54 ,  58  (and more particularly, the wear surfaces  56 ,  60 ) are fabricated from aluminum titanium carbide (ALTC) and in another embodiment, zirconium is employed to provide the desired lower wear rate. 
     In the illustrated “as-fabricated” embodiment of the core support  50 , the wear surfaces  56  and  60  of the edge members  54 ,  58  are at a height, H 3 , relative to the facing surface  22  of the head assembly  20 . This height is preferably equal to or greater than the height, H 2 , of the wear surfaces  66  of the nonmagnetic support member  64  and the core  26 . This may be achieved by initially fabricating the wear surfaces  56 ,  60  at a height, H 3 , greater than the height, H 2 , of the wear surface  66  of the nonmagnetic member  64 . Further, in the illustrated embodiment, the support surfaces  42 ,  48  of the elongated supports  40 ,  44  are at a height, H 1 , relative to the facing surface  22 , which is less than or equal to the height, H 2 , of the core  26  and the nonmagnetic support member  64  wear surface  66  (see, for example, FIG. 5 which illustrates this height differential). Of course, many heights may be utilized in initial fabrication, such as having H 1  being about equal to H 2 . The important design factor is that the edge members  54 ,  58  be harder and/or more wear resistant than the nonmagnetic support element  64  and core  26  and in some embodiments, harder and/or more wear resistant than the support surfaces  42 ,  48 . This hardness differential will typically result in the illustrated heights after tape  28  is run over the transducer support assembly  24  for a period of time. 
     In another preferred embodiment, the support surfaces  42 ,  48 , the wear surfaces  66  of the nonmagnetic support member  64 , the core  26 , and the wear surfaces  54 ,  60  of the wear-resistant edge members  54 ,  58  are initially fabricated to be substantially coplanar and at the same initial height (i.e., H 1 =H 2 =H 3 ). In this initial configuration, all of the wearing and support surfaces of the transducer support assembly  24  provide a relatively flat, coplanar surface that mates with the inner radius and contours of the tape  28  in the head assembly  20 . As the tape  28  is run across the wear and support surfaces that have differing wear rates (i.e., the wear surfaces  56 ,  60  of the edge members  54 ,  58  being lower or more wear resistant) the contacting surfaces will experience a pressure that is nonuniform along the length of the wear and support surfaces (i.e., along the longitudinal axis, a,). As discussed previously, a higher contact pressure is placed on the narrower support surfaces (i.e., w S  is less than the width, w CS , of the core support  50 ). Because the wear surfaces  56 ,  60  of the edge members  54 ,  58  are fabricated from a more wear resistant material such as ALTC, the support surfaces  42 ,  48  wear more rapidly and the height, H 3 , of the wear surfaces  56 ,  60  of the edge members  54 ,  58  quickly becomes larger than the height, H 1 , of the support surfaces  42 ,  48 . After this break in period, the height differential remains for the life of the head assembly  20  resulting in controlled airflow and wear protection. 
     Often, the core  26  and wear surface  66  of the nonmagnetic support member  64  are fabricated of materials similar in hardness as the support surfaces  42  and  48  but because these surfaces are protected by the edge members  54 ,  58  the wear rates experienced are less than those experienced at the support surfaces  42 ,  48 . Hence, after the initial break in period of wear, the height, H 2 , is less than the height, H 3 , of the wear surfaces  56 ,  60  of the edge members  54 ,  58  but greater than the height, H 1 , of the support surfaces  42 ,  48  of the elongated supports. The contact pressure becomes relatively uniform throughout the wear and support surfaces of the transducer support assembly  26  with some concentration of pressure remaining on the harder, wear-resistant edge members  54 ,  58 . 
     Referring back to FIGS. 2 and 4, during read/write operations with the tape head assembly  20 , the tape  28  will run over each of the wear surfaces  56 ,  60 ,  66 , over the core  26  and gap  38 , and the support surfaces  42 ,  48  of the elongated supports  40 ,  44 . The axis, a 1 , of the support surfaces is substantially perpendicular to the tape travel direction  32  while the core support  50  is wider with its axis being substantially parallel to the tape travel direction  32 . The technique of providing a wider tape wear surface in the area around the transducer element and a more narrow wear surface in adjacent regions of a transducer support assembly is described in detail in U.S. Pat. No. 5,426,551, entitled “Magnetic Contact Head Having A Composite Wear Surface” and U.S. Pat. No. 5,475,553 entitled “Tape Head With Self-Regulating Wear Regions,” both issued to George Saliba and both being incorporated fully herein by reference. These two patents describe in detail useful dimensions and geometries for the wear surfaces  66 ,  26  and support surfaces  42 ,  48  of the transducer support assembly  24  that are readily applicable by those skilled in the art to the present invention. 
     Note, these patents do not suggest the use of a harder, more wear-resistant leading edge member, such as members  54 ,  58 , and teach that wear would be expected to be substantially uniform on the surfaces of the wider transducer core support. In contrast, the present invention recognizes that even with a relatively uniform contact pressure along the longitudinal axis, a 1 , of the transducer support assembly  24 , localized higher pressure points typically will arise in head assemblies  20  and need to be addressed. 
     As illustrated in FIG. 4, the wear surfaces  56 ,  60  of the edge members  54 ,  58  and support surfaces  42 ,  48  of elongated supports  40 ,  44  are illustrated as rectangular but numerous initial shapes may be utilized to assist in initial manufacturing and to provide desired airflow conditions within the head assembly  20 . In operation, it will be understood that wear by the tape  28  alters the shapes of the contacting surfaces of the transducer support assembly  24 . For example, initially the surfaces are in an unworn condition, such as that shown in FIG. 4, and as the tape  28  begins to repeatedly advance across the wear surfaces the pressure exerted by the tape  28  is less on the wider core support  50  surfaces than on the narrower support surfaces  42 ,  48  of the elongated supports  40 ,  44 . This lower contact pressure may appear undesirable for providing good read/write contact, but the nonuniform contact pressure results in initial nonuniform wear such that after a short break in period the pressure becomes more uniform. 
     Due to the initial nonuniform wear on the wear surfaces the wider core support  50  becomes raised relative to the support surfaces  42 ,  48  of the elongated supports  40 ,  44 . Specifically, in an embodiment that utilizes materials of similar wear resistance for the core  26 , the nonmagnetic support member  64 , and the elongated supports  40 ,  44 , the core  26  and wear surface  66  of the nonmagnetic support member  64  become raised relative to the support surfaces  42 ,  48  due to the nonuniform pressure (i.e., H 2  becomes greater than H 1 ). Further, the use of more wear-resistant materials for the wear surfaces  56 ,  60  of the edge members  54 ,  58  results in these surfaces becoming raised relative to both the nonmagnetic support member  64  and the elongated supports  40 ,  44  (i.e., H 3  becomes greater than H 2  and H 1 ). 
     The wear results in a changing profile of the elements of the transducer support assembly  24 , as is best seen in FIGS. 6 and 7. As shown in FIG. 2, the tape  28  is wrapped around the tape head assembly  20  to form a tape radius or arc at each of the contacting transducer support assemblies  24 . The wear pattern of the tape  28  on the surfaces of the transducer support assembly  24  typically results in the surfaces obtaining rounded edges or curved planar surfaces. As illustrated in FIGS. 6 and 7, the profile of the transducer support assembly  24  shown in FIG. 5 formed by three arcuate wear or contact surfaces having slightly different radii (or, as will be explained below, the radius of the wear surfaces  56 ,  60  of the edge members  54 ,  58  may be substantially equal to the radius of the core  26 ). 
     As shown, the support surfaces  42 ,  48  have an arcuate cross-sectional shape when viewed along the axis, a 1 , that has a radius, R 1 . The two wear surfaces  56  and  60  of the edge members  54  and  58  are also curved or arcuate surfaces that are generally on the same arc having radius, R 3 . The surfaces  66  of the nonmagnetic support member  64  and the contact surface of the core  26  generally form a single curved or arcuate surface that has a radius, R 2 . Due to the selection of a harder and/or more wear resistant material for the wear surfaces  56 ,  60  and their location in the assembly  24 , these surfaces  56 ,  60  control the rate of wear in the assembly  24 . Pressure is initially concentrated on these surfaces  56 ,  60  and they wear more rapidly at first until wear begins to occur on the adjacent surfaces  26 ,  66 , and  42 ,  48 . After an initial break in period or service period, the assembly takes on an appearance or configuration as shown in FIGS. 6 and 7. 
     As shown, the radius, R 3 , of the wear surfaces  56 ,  60  is greater than or equal to the radius, R 2 , of the surface formed by surfaces  66  and the core  26 . In turn, the radius, R 2 , is greater than or equal to the radius, R 3 , of the support surfaces  42 ,  48 . In a preferred embodiment (as illustrated), the wear surfaces  56 ,  60 , the core  26 , and the nonmagnetic surfaces  66  form a single, substantially continuous, arcuate surface for contacting the tape  28  and having a radius greater than or equal to the radius, R 2 , of the core  26 . During operation, the edge members  54 ,  58  control the wear rate and the radius, R 3 , is self-regulating to remain greater than or equal to the radius, R 2 , of the core. For example, the radius, R 3 , of the wear surfaces  56 ,  60  may be in the range of about 0.3 to 0.7 milliinches while the radius, R 2  of the wear surface  66  of the nonmagnetic support member  64  and core  26  may be in the range of about 0.3 to 0.5 milliinches and the radius, R 1 , of the support surfaces  42 ,  48  may be less than about 0.3 to about 0.2 milliinches. 
     The break in period can also be accelerated or eliminated during manufacturing through the use of an abrasive lapping tape to remove or reduce any sharper contact edges. Significantly, the use of the harder, more wear-resistant material for the wear surfaces  56 ,  60  of the edge members  54 ,  58  allows these two surfaces  56 ,  60  to remain at substantially the same radius, R 3 , that is raised above or at the same radius as the adjacent surfaces and to contact the tape  28 , e.g., at a radius that is larger than the other contact radii and that better matches or suits the contour of the tape  28  as it is placed in tension within the head assembly  20 . 
     Once the break in period is completed, the wear rate becomes more uniform along the longitudinal axis, a 1 , of the transducer support assembly  24  and the core support  50  surfaces remain raised above or at a larger radius than the elongated supports  40 ,  44 . Relatively uniform wear is achieved according to the invention by utilizing more wear-resistant materials, such as ALTC, at the locations of higher contact pressure (i.e., at the edge members  54 ,  58 ). The process of wear on the tape contact surfaces of the transducer support assembly  24  is essentially self-regulating for the operational life of the head assembly  20 . When the raised core support  50  surfaces become relatively too high or low, the contact pressure along the longitudinal axis, a 1 , becomes more nonuniform until the radii, R 1 , R 2 , and R 3 , again adjust to acceptable differential levels (e.g., R ≧R   2 &gt;R 1 ) to better distribute the contact pressure applied by the tape  28 . 
     During operation of the head assembly  20 , the movement of the tape  28  as shown by arrow  32  across the tape facing surfaces  22  causes air to be moved or pushed toward the transducer support assembly  24 . Without airflow control, this moving air can lift the tape  28  away from the core  26  causing spacing losses. According to the invention, however, the combined use of a raised, wear-resistant edge member  54 ,  58  and a wider core support  50  effectively strips air from under the tape  28  at the important point of contact between the gap  38  of the core  26 . In practice, the air being moved by the tape  28  initially contacts the wider core support  50  at the leading one of the edge members  54 ,  58  which forces the air to the sides toward the elongated supports  40 ,  44 . 
     Additionally, the wear surfaces  56 ,  60  of the edge members  54 ,  58  are raised which enables the edge members  54 ,  58  to better contact the tape  28  to strip or direct away air moving along with the tape  28 . The redirected air instead flows over the lower support surfaces  42 ,  48  of the elongated support  40 ,  44  which provide a path of less resistance for the flowing air or down the channels on the facing surfaces  22  between the transducer support assemblies  24  on the head assembly  20 . In this manner, the present invention significantly enhances airflow control to provide better magnetic coupling between the core  26  and the moving tape  28 . 
     To modify the aerodynamics or airflow control of the invention, additional configurations can be used that provide different edge configurations between the support and wear surfaces to provide airflow that at the leading contact profile that may be useful for obtaining better contact with the media and/or wear. For example, another preferred embodiment of a transducer support assembly  124  is shown in FIG. 8 that includes a wider core support  150 . As in the transducer support assembly  24  (as initially manufactured), elongated supports  40 ,  44  are provided with support surfaces  42 ,  48  at a height, H 1 , and a width, W s , made of material such as ferrite or other material with a hardness and wear resistance similar to the materials of the included magnetic ferrite or other magnetic material core  26 . The core support  150  supports and surrounds the core  26  and gap  38  and nonmagnetic support member  164  and is wider than the width, W S , of the support surfaces  42 ,  48  to control the contact pressure applied by the tape  28  at the core  26  (as discussed above). A nonmagnetic support member  164  fabricated of ceramic material or other nonmagnetic material having wear surfaces  166  at a height, H 2 , is provided to support and isolate the core  26  (with H 2  being greater or equal to H 1  initially or after a break in period). 
     To alter aerodynamics, the core support  150  includes sloped and curved edge members  154 ,  158  with wear resistant surfaces  156 ,  160  fabricated of a higher wear-resistant material such as ALTC, zirconium, and the like and at a height, H 3 , greater than H 1  and H 2  initially or after break in wear. The shape of the surfaces  156 ,  160  is shown as substantially a semicircle but other shapes may be used in the invention as long as the surface extends beyond the surfaces  166  of the nonmagnetic support member  164 . 
     The semicircle shape facilitates the wear of the surfaces  156 ,  160  to a raised, smoother mound without sharp edges. This configuration is useful for reducing turbulent airflow that may cause the tape  28  to lift in the vicinity of the core  26  and also better distributes contact pressures to reduce the magnitude of concentrated tape pressure. Of course, the more rectangular wear surfaces  56 ,  60  shown for transducer support assembly  24  will wear in response to concentrated pressures at the leading edges and corners resulting in the surfaces  56 ,  60  taking on a more curved or semi-circle shape (as discussed with reference to FIGS.  6  and  7 ). 
     Although the invention has been described and illustrated with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example, and that numerous changes in the combination and arrangement of parts can be resorted to by those skilled in the art without departing from the spirit and scope of the invention, as hereinafter claimed. For example, the inventive transducer support assembly  24 ,  124  was illustrated for use in a linear tape head assembly  20  but the features of the transducer support assembly  24 ,  124  make it useful in numerous other tape head assembly configurations (not shown) such as a helical tape head assembly and in head assemblies in which the tape  28  runs transversely across the transducer support assembly at an angle other than 90 degrees. These different tape head assemblies may result in differing concentration of contact pressure that can readily be addressed with the use of the wear resistant edge members  54 ,  58  with or without modification to their shape and location relative to the core  26 .

Technology Classification (CPC): 6