Abstract:
A suspension is cantilevered at the tip end of a carriage arm. A magnetic head is mounted on the free end of the suspension. A lift bar in parallel with the disk surface contacts the suspension from the below. The lift bar may move in the path intersecting the suspension while contacting the suspension. The lift bar thus generates the warp in the suspension. The magnetic head at the free end of the suspension may be kept away from the disk surface as a result of the warp in the suspension. The adjustment of the orientation of the lift bar prevents the suspension from twisting.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a recording disk drive such as a hard disk drive unit (HDD), and in particular, to a recording disk drive comprising a recording disk, a suspension cantilevered on a carriage arm to tilt in the forward direction toward a disk surface of the recording disk, and a head supported at the free end of the suspension. 
     2. Description of the Prior Art 
     A flying head has been generally known capable of writing and reading information data to and from a recording disk or magnetic disk without contacting the disk surface of the recording disk, for example, in the field of hard disk drive units (HDDs). The lift of the flying head is usually generated by air stream flowing along the disk surface during rotation of the magnetic disk. When the rotation is terminated, the flying head cannot keep flying above the disk surface. No air stream leads to the result that the flying head is urged against the disk surface under the effect of elastic restoration of the suspension. The flying head must be prevented from contacting the data tracks or area on the disk surface when the rotation of the magnetic disk has been terminated. 
     A contact start stop (CSS) is well known in which the flying head is urged against the non-data tracks or an area at the innermost portion of the disk surface. The CSS allows the flying head to take off from the disk surface if enough air stream has been generated on the disk surface after the magnetic disk starts to rotate. However, in this CSS, the flying head must be released from adhesion from a lubricating oil or agent spread over the disk surface when the head takes off from the disk surface. As the size of a flying head gets smaller, it becomes nearly impossible for the flying head to easily take off from the disk surface once the flying head is urged against the disk surface. 
     On the other hand, a ramp load proposes a utilization of the warp of the suspension supported at the tip end of the carriage arm in avoiding the contact between the flying head and the stationary disk surface. The warp may be caused by a support member disposed outside the magnetic disk. As long as the warp of the suspension is kept, the flying head at the free end of the suspension can be kept away from the disk surface. If the flying head is positioned above the data tracks or area on the disk surface with the warp kept in the suspension, the flying head cannot contact the disk surface. No adhesion from a lubricating oil or agent acts on the flying head. 
     The support member of the ramp load is adapted to form a ramp in the path of the suspension. When the suspension climbs up the ramp in response to the swinging movement of the carriage arm, the warp gets larger in the suspension. The larger warp makes a higher position of the flying head above the disk surface. On the other hand, the ramp causes a twist in the suspension, too. If such twist remains in the suspension, the degree of the warp is changed in the suspension. This change may lead to deterioration in controllability of attitude and/or position of the flying head when information data is read out of or written in the magnetic disk. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the present invention to provide a suspension load mechanism contributing to prevention of a twist in a suspension supporting a head. 
     According to a first aspect of the present invention, there is provided a recording disk drive comprising: a recording disk; a suspension cantilevered on a carriage arm to tilt in a forward direction toward a disk surface of the recording disk; a head supported at a free end of the suspension; and a lift bar moveable along a path intersecting the suspension. 
     With the above-described recording disk drive, the warp in the suspension gets larger as the lift bar contacting the suspension advances in the path intersecting the suspension. As long as the warp is maintained in the suspension, the head at the free end of the suspension can be kept away from the disk surface of the recording disk. If the head is always shifted to positions above the data area with the warp kept in the suspension, the head can be prevented from contacting the disk surface. No adhesion acts on the head from a lubricating oil or agent spread over the disk surface. 
     The recording disk drive preferably further comprises a support member supporting the lift bar in parallel with the disk surface. If the lift bar is kept in parallel with the disk surface, it is possible to prevent the suspension from twisting by adjusting the orientation of the path of the lift bar to the tilting direction of the suspension. 
     The recording disk drive may further comprise a drive mechanism which generates a drive force acting on the support member to move the lift bar. In particular, the drive mechanism preferably comprises a cam formed on the carriage arm so as to cause the drive force in response to swinging movement of the carriage arm. Such advancement of the lift bar in response to the swinging movement of the carriage arm enables to eliminate a drive source to be added to the recording disk drive for driving the lift bar. However, the drive mechanism may be adapted to move the lift bar with assistance of any additional drive source without utilization to the swinging movement of the carriage arm. 
     The adjustment in orientation of the tilting direction of the suspension to the path of the lift bar may require an orientation adjuster causing a directional force to change an orientation of the lift bar in a plane parallel to the disk surface in response to the swinging movement of the carriage arm. For example, when the tilting direction is complied with the central line of the suspension, the suspension keeps the constant distance from the disk surface along the direction perpendicular to the central line. Accordingly, as long as the lift bar in parallel with the disk surface contacts the suspension at the line perpendicular to the central line, the constant distance from the disk surface can be maintained along the direction perpendicular to the central line in the suspension. The suspension can then be prevented from twisting. 
     The orientation adjuster may comprise: a first guide passage extending in a first direction along the path of the lift bar; a pivot moveable along the first guide passage so as to support the support member; a second guide passage extending in a second direction intersecting the first direction; and a guide member formed on the support member so as to move along the second guide passage in response to movement of the pivot, thereby causing swinging movement of the support member around the pivot. Such orientation adjuster enables the lift bar to follow the change in the orientation of the suspension in accordance with the swinging movement of the carriage arm. 
     In addition, the recording disk drive may further comprise an insertion mechanism generating a force to move the lift bar between a standby position defined outside the recording disk and an operating position defined between the suspension and the recording disk. Such insertion mechanism serves to keep the lift bar away from the recording disk while the head is operated to write or read information data. It is accordingly possible to reliably prevent the lift bar from interfering with the head, the suspension, the carriage arm, and the like. 
     The insertion mechanism may comprise: a support member supporting the lift bar at its tip end; a pivot supporting the support member for swinging movement; and a cam formed on the carriage arm so as to cause the swinging movement of the support member in response to swinging movement of the carriage arm. Such insertion mechanism enables the lift bar to shift between the standby and operating positions with assistance of swinging movement of the carriage arm. Such shift of the lift bar in response to the swinging movement of the carriage arm possibly eliminates a drive source to be added to the recording disk drive for driving the lift bar. However, the insertion mechanism may be adapted to move the lift bar with assistance of any additional drive source without utilization to the swinging movement of the carriage arm. 
     In case where the swinging movement of the carriage arm is utilized to move the lift bar between the standby and operating positions, the cam according to the insertion mechanism may also generate a drive force to cause advancement of the support member. A single drive source common to the insertion and drive mechanisms may lead to a simplified structure in the recording disk drive. 
     The recording disk drive may simultaneously comprise the insertion mechanism and the above-described orientation adjuster. In this case, the pivot in the insertion mechanism may be guided in the first guide passage of the orientation adjuster. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiment in conjunction with the accompanying drawings, wherein: 
     FIG. 1 illustrates a perspective view of a hard disk drive unit (HDD); 
     FIG. 2 is a plan view schematically illustrating the interior structure of the HDD; 
     FIG. 3 is an enlarged perspective view illustrating a suspension load mechanism according to the present invention; 
     FIG. 4 is an enlarged plan view illustrating a lift bar at the standby position during rotation of the magnetic disk; 
     FIG. 5 is an enlarged plan view illustrating a cam contacting a cam receiving protrusion when the insertion mechanism has been established; 
     FIG. 6 is an enlarged plan view illustrating the cam contacting the cam receiving protrusion at the moment when the insertion mechanism is switched over to the drive mechanism; 
     FIG. 7 is an enlarged plan view illustrating the lift bar at the operating position; 
     FIG. 8 is an enlarged plan view illustrating the cam contacting the cam receiving protrusion after the drive mechanism has been established; 
     FIGS. 9A and 9B are enlarged side views illustrating the suspension when the lift bar contacting the suspension advances along the path; 
     FIG. 10 is an enlarged plan view illustrating the suspension supported by the lift bar when the swinging movement of the carriage arm has been terminated; and 
     FIG. 11 is an enlarged sectional view taken along the line  11 — 11  in FIG. 10, illustrating the suspension. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 illustrates a hard disk drive unit (HDD)  10  as an example of a recording disk drive. The HDD  10  comprises a housing  11  which can be divided into a box-shaped housing body  12  and a cover  13  closing the opening of the housing body  12 . The HDD  10  may be assembled in a housing of a computer, or may be used as an external storage device independent of a computer. 
     As shown in FIG. 2, the housing  11  accommodates magnetic disks  16  sequentially mounted on a single spindle motor  15 , and a positioning mechanism  18  capable of positioning a set of magnetic heads  17  at respective target recording tracks on the magnetic disks  16 . The positioning mechanism  18  comprises carriage arms  20  capable of synchronously swinging around a common support axis  19 , and an actuator  21  comprising a magnetic circuit, for example. When the actuator  21  serves to cause the carriage arms  21  to swing, the magnetic heads  17  move in the radial direction of the magnetic disks  16  along the circular path established around the support axis  19 . 
     A suspension  22  is cantilevered at the tip end of the carriage arm  20  so as to tilt in the forward direction toward the disk surface of the magnetic disk  16 . The magnetic head  17  is supported at the free or tip end of the suspension  22 . If no external force acts on the suspension  22 , the magnetic head  17  at the tip end of the suspension  22  is urged against the disk surface of the magnetic disk  16 . When the magnetic disk  16  rotates, the magnetic head  17  receives air stream generated along the disk surface of the magnetic disk  16 , so that the magnetic head  17  flies above the disk surface allowing the small warp in the suspension. Information data is read out of or written in the magnetic disk  16  when the magnetic head  17  keeps flying. 
     A suspension load mechanism  23  according to the present invention is disposed outside a set of the magnetic disks  16  in the vicinity of the magnetic disks  16 . The suspension load mechanism  23  utilizes a warp generated in the suspension  22  at the tip end of the carriage arm  20  so as to avoid the contact between the magnetic head  17  and the stationary magnetic disk  16  when no rotation is effected on the magnetic disk  16 . 
     Referring to FIG. 3, the suspension load mechanism  23  comprises a pivot  26  supporting a support member  25  for swinging movement. A slider  28  is formed at the lower end of the pivot  26 . The slider  28  is received in a guide groove  27  as a first guide passage at the bottom of the housing body  12 . The pivot  26  is accordingly capable of moving forward and backward along the guide groove  27 . A spring  29  is connected to the support member  25  so as to generate a spring force which urges the pivot  26  toward a standard position at an end of the guide groove  27 , as shown in FIG.  3 . 
     Lift bars  31  are integrally formed at the forward end of the support member  25 . The lift bars  31  correspond to the respective magnetic heads  17  opposed to the respective disk surfaces of the magnetic disks  16 . For example, if four data areas are established on both sides of a pair of magnetic disks  16 , four lift bars  31  are provided corresponding to four magnetic heads  17  opposed to the respective data areas. The support member  25  keeps the lift bars  31  in parallel with the corresponding disk surfaces. 
     A cam receiving protrusion  32  is formed on the support member  25  so as to extend rearward from the pivot  26 . The cam receiving protrusion  32  is adapted to receive a cam  33  formed on the carriage arm  20 . The combination of the cam  33  and cam receiving protrusion  32  may be switched over between an insertion mechanism and a drive mechanism in response to the amount of swinging movement of the carriage arm  20 . When the insertion mechanism is established, the cam  33  and cam receiving protrusion  32  in cooperation serve to generate a drive force to swing the support member  25  around the pivot  26  which is kept at the standard position in the guide groove  27  with assistance of the spring force of the spring  29 . In this insertion mechanism, the carriage arm  20  is allowed to swing with an apex  33   a  of the cam  33  contacting the side surface  32   a  of the cam receiving protrusion  32 . When the drive mechanism is established, the cam  33  and cam receiving protrusion  32  in cooperation serve to generate a drive force to advance the pivot  26  from the standard position along the guide groove  27  against the spring force from the spring  29 . In this drive mechanism, the carriage arm  20  is adapted to swing with an apex  32   b  of the cam receiving protrusion  32  sliding on the cam surface  33   b  of the cam  33 . 
     An orientation adjuster  34  is connected to the lift bars  31  so as to cause a directional force to change the orientation of the lift bars  31  in corresponding planes parallel to the disk surfaces of the magnetic disks  16  in response to the advancement of the pivot  26  in the guide groove  27 . The orientation adjuster  34  may comprise a guide wall  35  formed at the bottom of the housing body  12  so as to extend in a second direction L 2  intersecting a first direction L 1  along the orientation of the guide groove  27 , and a guide member  36  integrally formed at the forward end of the support member  25 . The guide wall  35  serves to provide a second guide passage according to the present invention. The guide member  36  is adapted to contact the guide wall  35 . According to this orientation adjuster  34 , when the pivot  26  advances along the first direction L 1 , the guide member  36  is allowed to move in the second direction L 2  intersecting the first direction L 1 , so that the support member  25  swings about the pivot  26  to finally change the orientation of the lift bars  31 . 
     Next, the description will be made on the operation of the suspension load mechanism according to the present invention. As shown in FIG. 4, when the magnetic disks  16  rotate to allow the magnetic heads  17  to write or read information data, the support member  25  receives a spring force from the spring  29 , so that the lift bars  31  are maintained at the standby position defined outside a set of the magnetic disks  16  in the vicinity of the periphery of the magnetic disks  16 . The pivot  26  is pulled back to the standard position in the guide groove  27  with assistance of the spring force from the spring  29 . 
     When the rotation of the magnetic disks  16  is intended to be terminated after the magnetic heads  17  finish the writing or reading operation, the carriage arm  20  is operated to swing in the outward direction to bring the magnetic heads  17  off the magnetic disks  16 . The apex  33   a  of the cam  33  then contacts the side surface  32   a  of the cam receiving protrusion  32  as shown in FIG.  5 . The insertion mechanism has been established for the cam  33  and cam receiving protrusion  32 . Continuous swinging movement of the carriage arm  20  allows the apex  33   a  of the cam  33  to urge the side surface  32   a  of the cam receiving protrusion  32 , so that the support member  25  is caused to swing around the pivot  26  against the spring force from the spring  29 . As a result, the lift bars  31  gradually enter the corresponding spaces between the disk surfaces of the magnetic disks  16  and the carriage arms  20 . The swinging movement of the support member  25  is kept until the apex  33   a  of the cam  33  reaches the terminal edge of the cam receiving protrusion  32 . 
     When the apex  33   a  of the cam  33  has reached the terminal edge of the cam receiving protrusion  32  as shown in FIG. 7, the lift bars  31  are positioned at the operating position defined between the disk surface of the magnetic disks  16  and the tip end of the carriage arms  20 . The lift bars  31  at the operating position perpendicularly intersect the longitudinal central line L 3  of the suspensions  22 . 
     When the carriage arm  20  further swings, the apex  33   a  of the cam  33  takes off the side surface  32   a  of the cam receiving protrusion  32 . As a result, the apex  32   b  of the cam receiving protrusion  32  contacts the cam surface  33   b  of the cam  33  as shown in FIG.  8 . The drive mechanism has been established for the cam  33  and cam receiving protrusion  32 . The carriage arm  20  swings to allow the apex  32   b  of the cam receiving protrusion  32  to smoothly slide on the cam surface  33   b  of the cam  33 . The drive force is accordingly generated to advance the pivot  26  along the guide groove  27  against the spring force from the spring  29 . As the pivot  26  advances, the lift bars  31  is allowed to move in the forward direction toward the tip end of the suspensions  22 . 
     The lift bars  31  are adapted to contact the corresponding suspensions  22  as they advance along the path as shown in FIG.  9 A. Additional advancement after the contact between the lift bars  31  and the corresponding suspensions  22  serves to cause the suspensions  22  to warp, as shown in FIG. 9B, thereby bringing the tip end of each suspension  22  away from the corresponding disk surface of the magnetic disk  16 . The magnetic head  17  at the tip end of the suspension  22  is accordingly kept apart from the disk surface of the magnetic disk  16 . Such warp in the suspension  22  keeps the magnetic head  17  at the tip end of the suspension  22  sufficiently above the disk surface irrespective of the termination of the rotation of the magnetic disk  16 . 
     When the lift bars  31  still advance contacting the suspensions  22 , the warp gets larger in the suspensions  22 . The guide member  36  keeps contacting the guide wall  35 . Since a cross angle a has been established between the path of the pivot  26  in the first direction L 1  and the path of the guide member  36  in the second direction L 2 , as shown in FIG. 3, the advancement of the pivot  26  in the first direction L 1  causes the guide member  36  to move in the second direction L 2 , so that the support member  25  is allowed to swing around the pivot  26 . This swinging movement of the support member  25  enables to keep the perpendicular relationship between the central line L 3  of the suspensions  22  and the lift bars  31  irrespective of the change in the orientation of the suspensions  22  in response to the swinging movement of the carriage arm  20  as shown in FIG.  10 . 
     As is apparent from FIG. 11, the suspension  22  is adapted to make a tilt in the forward direction along the central line L 3 . The suspension  22  keeps the constant distance to the disk surface along the direction perpendicular to the central line L 3 . Accordingly, as long as the lift bars  31  in parallel with the disk surfaces perpendicularly intersect the suspensions  22  in the direction perpendicular to the central line L 3 , the suspensions  22  possibly keep the constant distance from the disk surface along the direction perpendicular to the central line L 3 . As a result, no twist may be generated in the suspensions  22 . Since such perpendicular relationship can be maintained between the central line L 3  and the lift bars  31  with assistance of the effect of the orientation adjuster  34  even when the lift bars  31  advance, the suspensions  22  can be prevented from twisting all the time. 
     After the magnetic heads  17  have completely taken off the magnetic disks  16 , the swinging movement of the carriage arm  20  is terminated. The lift bars  31  stop its advancement as shown in FIG.  10 . The magnetic heads  17  are kept away from the disk surfaces by enough height above the level of the disk surfaces, avoiding twist in the suspensions  22 . Even after the magnetic disks  16  have stopped rotating, the lift bars  31  keep the suspensions  22  away from the disk surfaces. 
     To the contrary, when the magnetic heads  17  are intended to write or read information data, the carriage arm  20  is operated to swing in the inward direction to bring the magnetic heads  17  toward the center of the magnetic disks  16  after the magnetic disks  17  have started rotating to generate enough air stream along the disk surface of the magnetic disks  16 . The swinging movement of the carriage arm  20  serves to gradually release the drive force acting on the apex  32   b  of the cam receiving protrusion  32  from the cam surface  33   b . The pivot  26  retracts in the guide groove  27  under the effect of the spring force from the spring  29 . The lift bars  31  are then released from the support to the suspensions  22 , however, the magnetic heads  17  keep flying above the disk surfaces with assistance of the air stream along the disk surfaces. 
     After the pivot  26  has been pulled back to the standard position in the guide groove  27 , the further swinging movement of the carriage arm  20  serves to gradually release the drive force acting on the side surface  32   a  of the cam receiving protrusion  32  from the apex  33   a  of the cam  33 . The support member  25  is allowed to swing about the pivot  26  under the effect of the spring force from the spring  29 . As a result, the lift bars  31  returns to the standby position from the operating position. 
     It should be noted that the above-described suspension load mechanism  23  may be applied, not only to the hard disk drive unit (HDD) as described above, but also to any recording disk drive unit employing a so-called flying head.