Patent Publication Number: US-2002008932-A1

Title: Gateway actuator

Description:
[0001] This application is a continuation-in-part of provisional Application Ser. No. 60/071,913 (Attorney Docket No. 18525-002700), filed Jan. 20, 1998, the full disclosure of which is herein incorporated by reference. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] The present invention is generally related to recording systems, in particular, provides methods and assemblies for manipulating components of a disk drive system.  
       [0003] Video Cassette Recorders (“VCRs”) dominate the consumer video market, due in part to their combination of low cost and recording capabilities. VCR analog magnetic tape recording cassettes can be used to record, play-back, and store video images in a format which is well adapted for use with existing analog television signals. The ability to record allows consumers to use the standard VHS VCR to save television shows and home movies, as well as for play-back of feature films.  
       [0004] The structure of VCR systems and recording media is adapted to record and archive existing television signals. Specifically, a large amount of analog data is presented on a standard television screen during a standard length feature film. VCR systems record this analog data using analog recording media. The VCR recordings can be removed from the recording/play-back equipment for storage, thereby reducing the system costs when large numbers of movies are stored.  
       [0005] While VCR systems successfully provide recording and archive capabilities at low cost, these existing consumer video systems have significant disadvantages. For example, accessing selected portions of a movie stored on a VCR tape can be quite slow and cumbersome. In particular, the cassette must be rewound to the beginning of the movie between each showing, which can involve a considerable delay. Additionally, transferring data to and from the tape takes a substantial amount of time. Although it would be beneficial to provide high speed accessing and transfer of the video data, this has remained a secondary consideration, as movies are typically recorded and played by the consumer in real time. Alternatives providing faster access are commercially available (for example, optical video disks), but these alternatives generally have not been able to overcome the VCR&#39;s low cost and recording capabilities.  
       [0006] Recent developments in video technology may further decrease the VCR&#39;s advantages over alternative systems. Specifically, standard protocols have recently been established for High Definition TeleVision (“HDTV”) signals. The digital data presented in a single HDTV feature film using these protocols can represent a substantial increase over existing VCR system capacities. While digital video cassette tapes are available, these modified versions of existing analog VCR systems do not appear to have sufficient storage capacity for a feature film in all of the proposed HDTV formats. Optical disks can accommodate these larger quantities of digital data. Unfortunately, despite many years of development, a successful low cost optical recording system has remained an elusive goal.  
       [0007] Personal computer magnetic data storage systems have evolved with structures which are quite different than consumer video storage systems. Modern personal computers often include a rigid magnetic disk which is fixed in an associated disk drive. These hard disk drive systems are adapted to access and transfer data to and from a recording surface of the disk at high speeds. It is generally advantageous to increase the total data storage capacity of each hard disk, as the disks themselves are typically fixed in the drive system. Hence, much of the data that is commonly used by the computer is stored on a single disk.  
       [0008] The simplicity provided by such a fixed disk drive system helps maintain overall system reliability, and also helps reduce the overall storage system costs. Nonetheless, removable hard disk cartridge systems have recently become commercially available, and are now gaining some acceptance. While considerable computer data can be stored using these removable hard disk cartridge systems, their complexity, less than ideal reliability, and cost has limited their use to selected numbers of high-end personal computer users.  
       [0009] One particular disadvantage of known removable hard disk computer storage systems is the complexity of the structure used to ensure that the internal working mechanisms of the disk drive system are free from environmental contamination and external interference. The disk drive system door must be actuated with sufficient strength such that the door can be opened and remain opened for a period long enough to allow a user to insert a removable cartridge. Known removable disk drive doors are generally actuated by incorporating spring, solenoid, or motor driven actuators or other biasing mechanisms. These structures typically have large space and power requirements, and are usually complex. Moreover, these structures can increase the manufacturing complexity and cost of the disk drive system.  
       [0010] For these reasons, a door actuator mechanism is neded tha will overcome at least some of the above mentioned disadvantages.  
       SUMMARY OF THE INVENTION  
       [0011] The invention provides assemblies and methods for manipulating components of a removable hard disk drive system. The invention uses mechanisms which are interconnected to cooperate in a manner which permits the manipulation of the components. The mechanisms are configured into an actuation assembly, which is used to cause the motion of, for example, the door of the external portion of the disk drive system. Specifically, the present invention moves the door with sufficient strength to open the door and allow it to remain open for a time period long enough to allow a user to insert or remove a disk cartridge. The actuation assembly includes a drive assembly which does not require a spring, solenoid, or motor as the primary actuating device. The large space and power quantities usually required by such devices is, therefore, substantially reduced. Since the present invention is simple in design and easy to manufacture, the overall cost of a disk drive system utilizing the actuation assembly is reduced.  
       [0012] Generally, the assembly includes a hinge device that can be made to rotate radially about or axially along a longitudinal axis. The hinge is coupled to an access panel, which is mounted on the housing of a disk drive system. As the hinge is made to rotate about a pivot point, the access panel is urged open or closed. To rotate the hinge, a driving member is used which is made of a specialized alloy, which is capable of contracting or expanding when heated. The contraction (or expansion) sets up a pulling force in the driving member, which is coupled to the hinge, to provide the force necessary to urge open the access panel door. As long as the heat is maintained, the alloy sustains the pulling force and the door will remain open. As the driving member cools, the pulling force is diminished. A biasing mechanism is used, which is coupled to the hinge, to stretch the driving member back to its original, uncontracted position and shape. As the driving member is pulled back to its original position, the hinge is simultaneously counter-rotated, which causes the access door to return to its closed position.  
       [0013] In one embodiment, a hard disk drive has an actuation assembly and a housing, which has a receptacle which removably receives a cartridge. The housing also has a cover, formed of a cover material and a front loading panel disposed over the receptacle. The actuation assembly includes a hinge assembly and a drive assembly, where the drive assembly has an alloy member which is coupled to the hinge assembly. A power supply is provided which generates an electrical current, the current being used to sufficiently raise the temperature of the alloy member causing the alloy member to undergo an internal change in structure thereby producing a force set within the alloy member. The force is of sufficient magnitude to actuate movement of the hinge assembly.  
       [0014] In an alternative embodiment, the drive assembly may further include a cam assembly which has a cam rotatable between an initial position and first and second extended positions; a cam spring in slidable contact with a portion of the cam member surface, whereby the cam spring engages the portion of the cam member surface to locate the cam member in each of the three positions; and a biasing member coupled to the cam member to return the alloy member back to the initial position following the removal of the alloy member force. The alloy member is made of a shape-memory alloy taken from a group of alloys which include products such as Nitinol™ and Flexinol™.  
       [0015] In another aspect, a method is provided for manipulating components of a removable hard disk drive. The removable hard disk drive having a housing which has a receptacle and removably receives a cartridge. The housing also has a cover, formed of a cover material and a front loading panel, disposed over the receptacle. The method includes selecting an alloy member which undergoes an internal change in structure when subjected to a change in temperature; generating an electrical current, the current used to sufficiently raise the temperature of the alloy member to produce a force set within the alloy member; and moving a component of the drive using the alloy member force.  
       [0016] In yet another aspect a method is provided which includes supplying energy to an alloy member causing the alloy member to undergo an internal change in structure thereby producing a force set within the alloy member; and actuating movement of an element by coupling said force to said element.  
       [0017] In yet another aspect, a method is provided for fabricating an actuation assembly for a hard disk drive having a housing which has a receptacle, which removably receives a cartridge, a cover formed of a cover material, and a front loading panel, disposed over the receptacle. The method includes selecting an alloy member, having a first end and a second end, which can undergo an internal change in structure, which produces a force within the alloy member; affixing the first end of the alloy member to a pivot assembly; and affixing the second end of the alloy member to a hinge mechanism, the hinge mechanism being coupled to a loading panel.  
       [0018] In yet another aspect, a disk drive system is provided for use with a removable disk cartridge. The disk drive system having a housing which has a receptacle, which removably receives the cartridge. The housing also having a cover formed of a cover material and a door. The door is coupled to an actuation assembly which includes a first arm coupled at a first end to the proximal end of a pivot shaft and coupled at a second end to the door; a second arm coupled at a first end to the distal end of a pivot shaft and coupled at a second end to a biasing mechanism; a shape-memory alloy wire mechanically coupled to the second end of the second arm and a position on the housing; a power supply activated by a switch positioned on the housing, wherein the power supply generates a current; and an electrical connection for applying the current to the wire, wherein the wire is heated by the current which causes the wire to contract generating a pulling force which is adapted to actuate the first and second arms. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0019]FIG. 1 is a schematic illustration of a video system including a high definition television and an external disk drive.  
     [0020]FIG. 1A is a simplified perspective view of an external disk drive for use with a removable rigid recording disk cartridge, according to an embodiment of the present invention.  
     [0021]FIG. 1B is a simplified perspective view of an internal disk drive similar to the external drive of FIG. 1, in which the internal drive is adapted for insertion into a standard bay of a computer or other housing.  
     [0022]FIG. 1C is a simplified schematic side view of an actuation device of the present invention fully inserted into the external disk drive of FIG. 1A.  
     [0023]FIG. 2 is a simplified schematic view of an alternative embodiment of the present invention using a cam assembly.  
     [0024] FIGS.  2 A- 2 C are simplified schematic views of the actuation assembly according to the alternative embodiment of FIG. 2 in operation.  
     [0025]FIG. 3 is a simplified schematic view of the actuation assembly according to an alternative embodiment of the present invention using a pivot rod assembly.  
     [0026]FIG. 4 is a perspective view of the internal disk drive of FIG. 1B, in which a cover of the disk drive has been removed to show a receptacle for the removable cartridge and some of the major disk drive components.  
     [0027]FIG. 5 is a perspective view of a removable cartridge housing a rigid magnetic recording disk.  
     [0028]FIG. 5A is an alternative perspective view of the cartridge of FIG. 5, showing the door and door actuation mechanism.  
     [0029]FIG. 6 is a simplified perspective view of the internal drive of FIG. 4, in which the voice coil motor and arm have been removed to show the cartridge release linkage and the head retract linkage.  
     [0030]FIG. 7A is a top view of a base for the internal drive of FIG. 4, in which the base is substantially entirely formed from sheet stock in a single stamping process.  
     [0031]FIG. 7B is a front view of the base of FIG. 7A.  
     [0032]FIG. 8A is a top view of the internal drive of FIG. 1B, in which the cover has been removed to show insertion of the cartridge of FIG. 5 therein.  
     [0033]FIG. 8B is a cross-sectional side view of the cartridge being inserted into the internal drive of FIG. 1B.  
     [0034]FIG. 9A is a cross-sectional side view of the cartridge of FIG. 5 fully inserted into the internal drive of FIG. 1B.  
     [0035]FIG. 9B is a top view of the cartridge inserted within the drive.  
     [0036]FIG. 9C is a perspective view of the disk drive housing cover, showing integral springs. 
    
    
     DESCRIPTION OF THE SPECIFIC EMBODIMENTS  
     [0037] Referring now to FIGS. 1A and 1B, external disk drive  10  and internal disk drive  20  will share many of the same components. However, external drive  10  will include an enclosure  12  adapted for use outside a personal computer, high definition television, or some other data manipulation or display device. Additionally, external drive  10  will include standard I/O connectors, parallel ports, and/or power plugs similar to those of known computer peripheral or video devices.  
     [0038] Internal drive  20  will typically be adapted for insertion into a standard bay of a computer. In some embodiments, internal drive  10  may instead be used within a bay in a HDTV, thereby providing an integral video system. Internal drive  20  may optionally be adapted for use with a bay having a form factor of 2.4 inches, 1.8 inches, 1 inch, or with any other generally recognized or proprietary bay. Regardless, internal drive  20  will typically have a housing  22  which includes a housing cover  24  and a base plate  26 . As illustrated in FIG. 1B, housing cover  24  will typically include integral springs  28  to bias the cartridge downward within the receiver of housing  22 . It should be understood that while external drive  10  may be very different in appearance than internal drive  20 , the external drive will preferably make use of base plate  26 , cover  24 , and most or all mechanical, electromechanical, and electronic components of internal drive  20 . Should the internal drive be used with the external drive, a front loading access panel  14  is included on the housing to provide access to the internal drive  20  for loading of a cartridge  60 .  
     [0039] As shown in FIG. 1C, an actuation assembly  100  is incorporated into an external drive  10 . Assembly  100  combines mechanisms, interconnected to cooperate in a manner which creates movement of components of external drive  10 .  
     [0040] Specifically, actuation assembly  100  includes a hinge assembly  126 , which is coupled to access panel  14 . Hinge assembly  126  is adapted so that it rotates about a pivot rod  130 , which defines the axis of rotation for the hinge assembly. Actuation assembly  100  also includes drive assembly  110 , which includes a drive member  120  and a biasing mechanism  135 . When activated as described below, drive member  120  causes the rotation of hinge assembly  126 . Biasing mechanism  135  is coupled to hinge assembly  126  and provides a mechanism for counter-rotating hinge assembly  126 .  
     [0041] Hinge assembly  126  has, typically, a first mechanical arm  127  coupled at a first end to pivot rod  130  and coupled at a second end to access panel  14 . Hinge assembly  126  also has a second mechanical arm  128  which is coupled at a first end to pivot rod  130  and coupled at a second end to biasing mechanism  135  and drive member  120 . Mechanical arms  127  and  128  are in a fixed relationship with pivot rod  130  and therefore rotate about rod  130  in proportion with the rotation of rod  130 . When a force is applied to pivot rod  130 , from either drive member  120  or biasing mechanism  135 , it rotates in either a clockwise or counter-clockwise direction, depending on the direction of the force applied. Mechanical arms  127  and  128 , both being coupled to pivot rod  130 , simultaneously rotate in the same direction. The first end of arm  127  coupled to access panel  14  rotates out of the housing through housing receptacle opening  150  to cause access panel  14  to rotate about its own hinge  134  until the access panel reaches a fully opened position.  
     [0042] The force used to drive pivot rod  130  and consequently to rotate arms  127  and  128  is generated within drive member  120 . Drive member  120  is made of an alloy material which possess inherent shape-memory properties. The shape-memory alloy is capable of contracting or expanding, an ability characteristic of certain alloys which dynamically change their entire structures when exposed to an energy source. The energy source must be capable of raising the temperature of the alloy. The energy may be in the form of electrical, thermal, or any similar type of energy. The contracting (or expanding) of the member sets up a tensile (or compressive) force within the drive member. The present invention typically uses the member in contraction mode, but it can be configured such that the expansion mode is used. The contraction of the wire occurs in a manner opposite to ordinary thermal expansion and is both smooth and silent. The contraction of the alloy is more significant in magnitude then is thermal expansion in other metals. Advantageously, the alloy exerts a more powerful force in relation to its size than is realized in other materials. In operation, energy is supplied to drive member alloy  120 . The alloy contracts which causes alloy  120  to shrink, creating a contraction force. One end of alloy drive member  120  is secured at a fixed point in the housing so that the work provided by the contraction force is applied solely to rotating pivot rod  130 . The force causes pivot rod  130  to rotate which, in turn, causes hinge assembly  126  to also rotate. Since access panel  14  is coupled to arm  127  of hinge assembly  126  it is made to swing open about its own hinge  134 .  
     [0043] Drive member  120  may take the form of a wire, flat ribbon, or other similar form, and is typically made of a known nickel-titanium (Ni—Ti) alloy, commonly referred to as a shape-memory alloy and commercially referred to as Nitinol™ or Flexinol™. As shown in Table 1, the contraction force can range from between 7 gms to 930 gms, depending primarily on the wire diameter. The energy supplied to the wire, generally, causes the wire to rise in temperature. The higher temperature typically being induced, for example, electrically. However, the alloy can be made to expand or contract if heated in various other manners, such as exposing the alloy to a heating element or to hot air. The shape-memory alloy may contract by several percent of its length and is easily stretched back to its original length as it cools back to a predetermined temperature. Heating and cooling of the wire occurs relatively quickly. For example, table 1 indicates that the contraction time of an Ni—Ti alloy wire is approximately 1 second, independent of the wire diameter, and a wire of 0.004″ diameter will return to its un-contracted state in between 0.4 to 0.8 seconds, depending on the temperature that the wire is finally elevated. The data provided in Table 1 are exemplary.  
     [0044] In a specific embodiment described here for exemplary purposes only, the present invention uses a drive wire  120  of a diameter between about 0.001″ and 0.010″, preferably between about 0.002″ and 0.006″. Wire  120  is heated to between approximately 70° C. and 100° C. The temperature makes the wire contract in approximately 1 to 2 seconds, however, 1 second is preferred. The quantity of force required in the wire is dictated by the weight of the door, the efficiency of the hinge, friction in the system, and other factors. However, the force can range from about 7 gms to 930 gms, preferably between about 80 gms to 330 gms, but the force is not limited to these ranges. When the energy source is removed from wire  120 , the wire will cool which will return the wire back to its original length in approximately 0.05 seconds to 6.0 seconds.  
                                       TABLE 1                                   Approxi-                               mate                       Resis-       Current at       Off   Off       Diam-   tance       Room   Contrac-   Time   Time       eter   Ohms/   Maximum   Tempera-   tion   70 C   90 C       Size   Inch   Pull Force   ture   Time   Wire   Wire                                                            .001″   45    7 gms    20 mA   1 sec    .1 sec   .06 sec       .002″   12    35 gms    50 mA   1 sec    .3 sec    .1 sec       .003″   5    80 gms   100 mA   1 sec    .5 sec    .2 sec       .004″   3   150 gms   180 mA   1 sec    .8 sec    .4 sec       .005″   1.8   230 gms   250 mA   1 sec   1.6 sec    .9 sec       .006″   1.3   330 gms   400 mA   1 sec     2 sec   1.2 sec       .008″   .8   590 gms   610 mA   1 sec   3.5 sec   2.2 sec       .010″   .5   930 gms   1000 mA    1 sec   5.5 sec   3.5 sec                  
 
     [0045] The biasing mechanism  135 , which is typically in the form of a spring which provides the force necessary to stretch alloy wire  120  back to its original length, while simultaneously counter-rotating hinge assembly  126 . Biasing mechanism  135  is coupled to the second arm  128  of hinge assembly  126 . The counter-rotating action reverses the movement of the rocker arms  127  and  128  and forces door  14  to close.  
     [0046] In the event that the contraction forces is greater than is necessary for moving door  14  or else if, for example, the access door  14  is prevented from opening, a biasing device  134 , may be coupled between the end of alloy wire  120  and the point to which alloy wire  120  is secured in the housing. The biasing device  134  can absorb an excessive force exerted by alloy wire  120 , thereby reducing the potential for damaging the actuation assembly or the disk drive system.  
     [0047] Although the heat of the wire is not expected to reach a temperature that would be damaging to the system, alloy wire  120  can be protected in a protective sheath, so as to protect the internal drive  20  or other components of the external drive. The protective sheath may be made of a heat absorbent material, such as the product Teflon™.  
     [0048] A pair of hinge assemblies can be used, each disposed at opposite ends of access panel  14  within external drive  10 . The dual hinge assemblies provide a balanced force applied to the door  14  for improved operation. The two hinge assemblies may be operated by the force generated in one wire  120 , simultaneously coupled to both assemblies or each assembly may have its own force generating wire  120  attached to it. In either case, the current provided by the power supply can be used for both assemblies.  
     [0049] In an alternative embodiment, shown in FIG. 2, single hinge  126  is adapted to be coupled to pivot rod  130  and to access panel  14 . On a portion of arm  126 , a channel  133  is formed which receives drive member  120 . A first end  121  of drive member  120  is coupled to a cam assembly  140 . Cam assembly  140  includes cam  141 , which has a raised bump portion  160 , and biasing spring  136 . Drive member  120  is wrapped around channel  133  and reconnected at a second end  122  to biasing spring  136 . A portion of drive member  120  may be replaced between points  122  and  123  on drive member  120  with a cable  152 . In this case, cable  152  may be attached to biasing spring  136  at attachment point  122 . The cable makes it possible to lengthen the extent of drive member  120  without increasing the contraction force magnitude of the drive assembly.  
     [0050] The alternative embodiment of the present invention provides for varying modes of operation in which the disk drive system must function. FIG. 2A illustrates a first mode or normal mode of operation in which the actuation assembly opens access door  14 . Drive member  120  is activated and operates as described above with regard to the force generated within the member. As drive member  120  contracts, cam assembly  140  provides an opposite reactive force such that the work produced by the contraction force is applied to hinge arm  126 . Cam  141  is typically adapted to rotate about point  145 , however, to ensure that cam  141  will not rotate clockwise in response to the application of the contraction force, a cam spring  170  is provided which slidably contacts cam  141  and abuts raised bump  160 . Accordingly, hinge arm  126  rotates causing access door  14  to open the disk drive. After door  14  is opened to its fullest extent, the energy supplied to member  120  is maintained so that the temperature of the drive member  120  remains elevated and the door  14  will remain opened. To ensure that drive member  120  does not open door  14  beyond a predetermined amount, biasing spring  136 , to which the second end  122  of drive member  120  or cable  152  is attached, absorbs the excess force. The excess force is stored in biasing spring  136  as potential spring energy and is used to counter-rotate hinge  126  at the appropriate time. A switch  180  is positioned in the disk drive which contacts door  14  in the closed position. When switch  180  is released, as when the door begins to rotate open, switch  180  senses the release and begins a clock timer which will indicate that the energy supplied to drive member  120  should be stopped after a predetermined time interval, allowing drive member  120  to cool and for the potential energy in spring  136  to counter-rotate access door  14  to close.  
     [0051] In a second mode of operation illustrated in FIG. 2B, it is anticipated that a user may attempt to close access door  14  manually before the energy supplied to drive member  120  has been deactivated so that the contraction force is still in full effect. Since the door is being forced to close, cam  141  rotates counter-clockwise allowing door  14  to close while maintaining the integrity of drive member  120 . As door  14  closes it depresses witch  180  and the energy supply is removed. Cam  141  returns to its initial position, as shown in FIG. 2, by the potential energy stored in biasing spring  136 .  
     [0052] In a third mode of operation illustrated in FIG. 2C, a user may attempt to manually open access door  14  while the activation system is deactivated. The force required to manually open door  14  will cause cam  141  to rotate in a clockwise direction. In this case, cam spring  170  slides over raised portion  160  and abuts the opposite side of the bump holding access door  14  open until drive member  120  is activated by switch  180  that senses when the door has been opened, and energizes drive member  120 . The contraction force, not needed to open door  14 , is directed to cam  141  to counter rotate cam  141  until cam spring  170  slides back over the bump and again abuts the bump at its initial position, as shown in FIG. 2. If at any time the door is open when the internal mechanisms of the disk drive are energized. Switch  180  will sense that door  14  is not closed. Drive member  120  will be energized for approximately 3 seconds, so that cam  141  can reset. Door  14  will then subsequently close.  
     [0053] In yet another alternative embodiment, as illustrated in FIG. 3, hinge  126  is adapted to be coupled to pivot rod  130  and to access panel  14 . On a portion of arm  126 , a channel  133  is formed which receives drive member  120 . A first end  121  of drive member  120  is coupled to a pivot assembly  200 . Pivot assembly  200  includes pivot bar  182 , which pivots about a point  190 , and biasing spring  187 . Drive member  120  is wrapped around channel  133  and reconnected at a second end  122  to biasing spring  187 .  
     [0054] Drive member  120  is energized and operates as described above with regard to the force generated within the member. As drive member  120  contracts, pivot assembly  200  provides an opposite reactive force through springs  185  and  186 , such that the work produced by the contraction force is directed to hinge arm  126 . Accordingly, hinge arm  126  rotates causing access door  14  to open the disk drive. After door  14  is opened to its fullest extent, the energy supplied to member  120  is maintained so that door  14  will remain opened. As before, to ensure that drive member  120  does not open door  14  beyond a predetermined amount, biasing spring  187 , to which the second end  122  of drive member  120  or cable  152  is attached, absorbs the excess force. The excess force is stored in biasing spring  187  as potential spring energy and is used to counter-rotate hinge  126  to close door  14 . The embodiment will also function in each of the modes of operation described above.  
     [0055] Many of the components of internal drive  20  are visible when cover  24  has been removed, as illustrated in FIG. 4. In this exemplary embodiment, a voice coil motor  30  positions first and second heads  32  along opposed recording surfaces of the hard disk while the disk is spun by spindle drive motor  34 . A release linkage  36  is mechanically coupled to voice coil motor  30 , so that the voice coil motor effects release of the cartridge from housing  22  when heads  32  move to a release position on a head load ramp  38 . Head load ramp  38  is preferably adjustable in height above base plate  26 , to facilitate aligning the head load ramp with the rotating disk.  
     [0056] A head retract linkage  40  helps to ensure that heads  32  are retracted from the receptacle and onto head load ramp  38  when the cartridge is removed from housing  22 . Head retract linkage  40  may also be used as an inner crash stop to mechanically limit travel of heads  32  toward the hub of the disk.  
     [0057] Base  26  preferably comprise a stainless steel sheet metal structure in which the shape of the base is primarily defined by stamping, the shape ideally being substantially fully defined by the stamping process. Bosses  42  are stamped into base  26  to engage and accurately position lower surfaces of the cartridge housing. To help ensure accurate centering of the cartridge onto spindle drive  34 , rails  44  maintain the cartridge above the associated drive spindle until the cartridge is substantially aligned axially above the spindle drive, whereupon the cartridge descends under the influence of cover springs  28  and the downward force imparted by the user. This brings the hub of the disk down substantially normal to the disk into engagement with spindle drive  34 . A latch  46  of release linkage  36  engages a detent of the cartridge to restrain the cartridge, and to maintain the orientation of the cartridge within housing  22 .  
     [0058] A cartridge for use with internal drive  20  is illustrated in FIGS. 5 and 5A. Generally, cartridge  60  includes a front edge  62  and rear edge  64 . A disk  66  (see FIG. 7B) is disposed within cartridge  60 , and access to the disk is provided through a door  68 . A detent  70  along rear edge  64  of cartridge  60  mates with latch  46  to restrain the cartridge within the receptacle of the drive, while rear side indentations  72  are sized to accommodate side rails  44  to allow cartridge  60  to drop vertically into the receptacle.  
     [0059] Side edges  74  of cartridge  60  are fittingly received between side walls  76  of base  26 , as illustrated in FIG. 6. This generally helps maintain the lateral position of cartridge  60  within base  26  throughout the insertion process. Stops  78  in sidewall  76  stop forward motion of the cartridge once the hub of disk  66  is aligned with spindle drive  34 , at which point rails  44  are also aligned with rear indents  72 . Hence, the cartridge drops roughly vertically from that position, which helps accurately mate the hub of the disk with the spindle drive.  
     [0060] The structure of base  26  can be seen most clearly in FIGS. 6, 7A, and  7 B. Base  26  generally comprises a stamped sheet metal structure, ideally being formed of stainless steel. Openings  80  accommodate the spindle drive, data transmission cables, component mounting fasteners, and the like. Openings  80  are substantially formed during the stamping process, but may optionally be modified afterward to provide threaded openings, etc. Mounting pads  82  are also generally defined by the stamp tools, so that head load ramp  38 , the head support structure (which generally includes voice coil motor  30  and head support arm  50 , as illustrated in FIG. 4), and spindle drive  34  are substantially located relative to each other.  
     [0061] Bosses  42  and side wall  76  are also formed by clamping the sheet metal stock between the male and female tool parts, while side rails  44  and stops  78  may be formed by independently movable tool portions. Hence, the cartridge engaging surfaces and component mounting pads are positioned on base  26  simultaneously during the relatively rapid stamping process, rather than individually machining each of these surfaces.  
     [0062] Once base  26  is stamped to shape, the various components may be mounted to the base to assembly the disk drive. Voice coil motor  30  and arm  50 , which together support head  32  (see FIG. 4) are mounted directly to their associated pad  82 . Spindle drive  34  will then be bonded to the base material which extends downward from its associated opening  80 . The driving member will rotate about a fixed position, rather than telescoping axially to engage the disk within the cartridge. The position of the spindle drive assembly can be adjusted during the bonding process using a gauge to align the disk on the spindle drive with the motion of heads  32 .  
     [0063] Head load ramp  38  is also mounted on an associated stamped pad  82  of base  26 . The head load ramp will preferably flex about a central fulcrum  84 . This facilitates adjustment of a height of the head load ramp over the base using a rear screw  86 , as more fully described in co-pending U.S. patent application Ser. No. 08/970,282, filed concurrently herewith (Attorney Docket No. 18525-000800) and assigned to the present assignee, the full disclosure of which is incorporated herein by reference. This allows the height of the head load ramp adjacent the disk to be easily adjusted so as to smoothly transfer the heads between the recording surface and a “park” position along the head load ramp.  
     [0064] Also formed during the stamping process are linkage mounts  88 . Release linkage  36  and head retract linkage  40  will be mounted to linkage mounts  88  using rivets or other fasteners which accommodate the sliding and/or pivoting of the linkage members, as appropriate.  
     [0065] Heads  32  will often be separated from the spinning recording surface by a thin layer of air. More specifically, the data transfer head often glides over the recording surface on an “air bearing,” a thin layer of air which moves with the rotating disk. Although recording densities are generally enhanced by minimizing the thickness of this air bearing, often referred to as the glide height, glide heights which are too low may lead to excessive contact between the head and the disk surface, which can decrease the reliability of the recording system. To avoid a head crash (in which the data transfer head contacts and damages the disk), the disk drive system of the present system will generally position heads  32  on head load ramp  38  whenever the disk is rotating at insufficient velocity to maintain a safe glide height.  
     [0066] Referring now to FIGS.  8 A- 9 C, arm  50  pivotally supports heads  32 . When no cartridge is disposed in internal drive  20  and no power is supplied to voice coil motor  30 , biasing springs of head retract linkage  40  and release linkage  36  urge arm  50  to a parked position on head load ramp  38 . As cartridge  60  is inserted into the receptacle of internal drive  20 , the cartridge actuates head retract linkage  40  so that the voice coil motor is free to pivot the arm from the parked position.  
     [0067] Cover springs  28  are manufactured or formed directly into the disk drive cover  24  and extend from the cover  24  toward the receptacle of internal drive  20  (see FIG. 4). Openings  27 , preferably being opposed relative to an axis of insertion of the cartridge  60 , are cut into housing cover  24  to define the spring structures. At least a portion of the cover material from the openings is not removed, but remains attached to the housing cover to provide the material for the springs. The cover material will typically be stainless steel or some other resilient material. To prevent the introduction of foreign elements into the internal disk drive through the openings, the openings can be subsequently covered with a plastic or similar material.  
     [0068] As shown in FIG. 9C, the cover material is split into two elongate strips  28   a ,  28   b  which extend in cantilever from the cover attach point  23  toward the receptacle. The springs preferably angle inward relative to the axis of insertion. Each spring  28  is adapted to slidingly engage the cartridge  60  to facilitate insertion and removal of the cartridge from the receptacle. Advantageously, the force applied by the springs  28  to the cartridge  60  will be no more than necessary to bias the cartridge toward the receptacle.  
     [0069] In a preferred embodiment, the elongate strips  28   a  each have a protrusion  29  adjacent to the free end of the strips. This protrusion  29  is adapted to resist introduction of the cartridge  60  so that the two opposed springs promote even advancement of the cartridge relative to the axis of insertion.  
     [0070] Specifically, during insertion, cover springs  28  urge forward edge  62  of cartridge  60  downward, while rear edge  64  remains elevated (so long as the cartridge rides along rails  44 ). As cartridge  60  slides into the receiver, biasing spring  90 , attached to head retract linkage  40  is tensioned. Biasing spring  102  is generally overcome manually during insertion of the cartridge.  
     [0071] Once cartridge  60  is inserted so that disk  66  is substantially aligned axially with spindle drive  34 , rear side indentations  72  (see FIG. 5) allow rear edge  64  of the cartridge to drop downward below rails  44 . This downward movement is opposed by base springs  94 . These base springs generally comprise simple wire structures screwed or otherwise fastened to base  26 , and the upward urging force imposed on cartridge  60  by the base springs is again manually overcome during insertion.  
     [0072] As base springs  94  are compressed against base  26 , latch  46  slides into detent  80 , so that the latch restrains cartridge  60  within the receiver of internal drive  20 . Simultaneously, spindle drive  34  aligns with and engages the hub of disk  66 , with centering alignment and driving engagement between the spindle drive and the disk generally being facilitated by a protruding, tapering nose on a magnetic chuck of the spindle drive and a corresponding counter sunk armature at the hub of disk  66 .  
     [0073] As described hereinabove, the door of the cartridge opens automatically during insertion of the cartridge. Actuation of head retract linkage  40  during insertion also frees arm  50  to move heads  32  from head load ramp  38  to recording surfaces  92  along the major surfaces of disk  66 .  
     [0074] While cartridge  60  is disposed within the receptacle of drive  20 , the position of the cartridge is generally maintained by engagement between the surfaces of the cartridge and the stamped surfaces of base  26 . More specifically, cover springs  28  and latch  46  hold cartridge  60  in contact with bosses  42 , thereby ensuring alignment between the major surfaces of the cartridge and the disk drive structure. The fore and aft position of the cartridge is generally maintained by engagement between side rails  44  and rear indentation  72 , with head retract linkage  40  biasing these two elements against each other. As described above, the sidewalls of base  26  fittingly receive side edges of cartridge  60 , so that the position of the cartridge within the receptacle is substantially fully constrained. The tolerance of the positioning of the cartridge within drive  20  should be sufficient so that the disk within the cartridge is rotatable within the cartridge housing, and so that the heads (as supported by the head support structure) have free access to the recording surfaces of the disk.  
     [0075] As described above, cartridge  60  is held in the receiver of internal drive  20  by engagement of latch  46  with detent  70 . Voice coil motor  30  may effect release of the cartridge by engagement between a tab of arm  50  and a corresponding tab on release linkage  36 . Expulsion of the disk from the receptacle of internal drive  20  is effected after the disk has spun down with heads  32  safely parked along head load ramp  38 . Voice coil motor  30  actuates release linkage  36  so as to disengage latch  46  from detent  80 .  
     [0076] When the latch is disengaged, engagement between rails  44  and indents  72  initially prevents the cartridge from sliding along the plane of the disk. Instead, base springs  94  urge rear edge  64  of cartridge  60  upward, disengaging spindle drive  34  substantially axially from the hub of the disk. Once these driving structures are safely disengaged, biasing spring  90  of head retract linkage  40  urges cartridge  60  out of the receiver, and the head retract linkage also ensures that arm  50  is safely positioned with heads  32  along head load ramp  38 . Generally, the biasing system will slide the cartridge rearward so that a portion of the cartridge extends from the drive, and so that the cartridge can be easily manually removed and replaced by the user.  
     [0077] While the exemplary embodiment has been described in some detail, by way of example and for clarity of understanding, a variety of modifications, changes, and adaptations will be obvious to those of skill in the art. For example, the invention has described rocker arms or hinge assemblies used to urge open the disk drive access panel door. It may be possible to replace the hinges with a pulley system that will use the inherent mechanical advantage of the pulley to open the door. In another example, the actuation assembly can be adapted for ejection of a disk cartridge from the disk drive system. An eject button may activate the assembly causing the contraction forces to manipulate mechanisms which will, in turn, release the cartridge. Another example can include the internal drive, which can be urged forward at an angle through the receptacle portion of the housing to be in an elevated position to receive the disk cartridge. Therefore, the scope of the present invention is limited solely by the appended claims.