Abstract:
A carriage arm assembly includes: a carriage arm that holds a head slider and a head IC communicating with the head slider and has a first engagement part between the head slider and the head IC; a signal relay member that are provided on the carriage arm and relays signals between the head slider and the head IC; and a presser member that has a second engagement part engaged with the first engagement part and is attached to the carriage arm by engaging the first and second engagement parts with each other, the signal relay member being held by a projection provided in one of the carriage arm and the presser member and a recess that is provided in the other and is engaged with the projection.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2008-137323, filed on May 26, 2008, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The present invention generally relates to a carriage arm assembly, a disk drive and a presser member, and more particularly, to a carriage arm assembly having a signal relay member, a disk drive equipped with the above carriage arm assembly, and a presser member that presses the signal relay member against a carriage arm. 
       BACKGROUND 
       [0003]    Recently, there has been considerable activity in the research and development of speeding up data transfers due to increase in the recording density in disk drives for data recording and reproduction. The speedup of data transfer requires improvements in a carriage arm assembly (which may be called head stack assembly) composed of a suspension and a carriage arm both having wiring lines for carrying signals. For example, the type of the carriage arm assembly is being changed to a short tail type from a long tail type. The short tail type has a shortened signal relay member integrally formed with a suspension, and the long tail type has a relatively long signal relay member. 
         [0004]    In the long tail type, high-speed airflow in the vicinity of the signal relay member caused by rapid rotation of the disk may vibrate the signal relay member. Thus, vibration of the signal relay member vibrates the magnetic head. This degrades positioning accuracy necessary for high-density recording. It is thus required to restrain vibration of the signal relay member in order to realize high-density recording. 
         [0005]    Recently, the long tail tape of signal relay member has been improved to reduce vibration. In this improvement, the signal relay member is in tight contact with the carriage arm, and an adhesive is dropped to the contact area. Thus, the signal relay member is bonded to the carriage arm. 
         [0006]    The signal relay member must be detached from the carriage arm if the carriage arm assembly is determined as being faulty in the performance test of the head that is carried out after the carriage arm assembly is assembled. The bonding using adhesive causes the signal relay member to be peeled from the carriage arm. Adhesive remains on the signal relay member, and it is troublesome to remove the remaining adhesive. 
         [0007]    In order to overcome the above drawback, there has been a proposal to hold an extended wiring part in the center of a groove in an extended wiring part holding part by utilizing repulsive force of a spring member (see Japanese Patent Application Publication No. 2005-243171). There is another proposal to form a slit for holding the signal relay line of long tail type in the actuator arm and hold both the parts due to the friction between the signal relay line and the actuator arm in the slit (see Japanese Patent Application Publication No. 2007-179683). 
         [0008]    However, the first proposal may not provide satisfactory effects of restraining vibration because this proposal uses only the elastic force of the spring member that is as thin as, for example tens of μm, and has difficulty in securely attaching the extended wiring part to the extended wiring part holding part. 
         [0009]    The second proposal does not fixedly attach the actuator arm and the long tail to each other and does not have sufficient restrain of vibration in certain revolutions of the disk. 
       SUMMARY 
       [0010]    According to an aspect of the present invention, there is provided a carriage arm assembly including: a carriage arm that holds a head slider and a head IC communicating with the head slider and has a first engagement part between the head slider and the head IC; a signal relay member that are provided on the carriage arm and relays signals between the head slider and the head IC; and a presser member that has a second engagement part engaged with the first engagement part and is attached to the carriage arm by engaging the first and second engagement parts with each other, the signal relay member being held by a projection provided in one of the carriage arm and the presser member and a recess that is provided in the other and is engaged with the projection. 
         [0011]    According to another aspect of the present invention, there is provided a disk drive including: a disk medium; and a carriage arm assembly used to write and read data into and from the disk medium and configured as described above. 
         [0012]    According to yet another aspect of the present invention, there is provided a presser member including: an engagement part engaged with an engagement part of a carriage arm having a head slider and a head IC; and a fitting portion engageable with one of a projection and a recess provided in the carriage arm in a state in which the presser member is engaged with the carriage arm, the fitting portion holding a signal relay member together with said one of the projection and the recess. 
         [0013]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
         [0014]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a plan view of a head disk drive according to an embodiment of the present invention; 
           [0016]      FIG. 2A  is a plan view of a head stack assembly, and  FIG. 2B  is a side view of the head stack assembly; 
           [0017]      FIG. 3A through 3C  are exploded perspective views of an end portion of the head stack assembly; 
           [0018]      FIG. 4  is a perspective view of a presser member; 
           [0019]      FIGS. 5A through 5F  are respectively cross-sectional views that illustrate the presser member and signal relay members of long tail type; 
           [0020]      FIG. 6  is a cross-sectional view illustrating effects brought about by holding signal relay members by the presser member and a carriage arm; 
           [0021]      FIGS. 7A and 7B  are cross-sectional views of tab portions of the presser member; 
           [0022]      FIGS. 8A and 8B  are cross-sectional views of a first variation of the combination of a projection and a recess; 
           [0023]      FIGS. 9A and 9B  are cross-sectional views of a second variation of the combination of the projection and the recess; 
           [0024]      FIGS. 10A through 10C  are cross-sectional views of a variation of a structure that realizes the engagement of the presser member and the carriage arm; and 
           [0025]      FIGS. 11A and 11B  are cross-sectional views of a variation in which slits are formed in the carriage arm. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0026]    A description will now be given, with reference to  FIGS. 1 through 7B , of embodiments of the present invention. 
         [0027]      FIG. 1  depicts an internal structure of a hard disk drive (HDD)  100 , which is an example of the disk drive in accordance with an embodiment of the present invention. As illustrated in  FIG. 1 , the HDD  100  has an enclosure  10  of a box type having an inner space (housing space) in which there are provided two magnetic disks  12 A and  12 B, a spindle motor  14 , and ahead stack assembly (HSA)  20 , which is an exemplary structure of a carriage arm assembly. The magnetic disk  12 B is hidden behind the magnetic disk  12 A. The enclosure  10  is composed of a base and an upper lid (top cover). In  FIG. 1 , only the base is illustrated for the sake of simplicity. The HDD is not limited to two disks and may have a single disk or three or more disks. The following description is directed to the HDD with the two disks. 
         [0028]    Each of the disks  12 A and  12 B has front and back recording surfaces. The disks  12 A and  12 B are integrally rotated by the spindle motor  14  about a rotating shaft at a speed as high as 4200 rpm to 15000 rmp. Each of the magnetic disks  12 A and  12 B may a base plate on which an underlying layer, a magnetic layer, a protection film and a lubrication layer are laminated in this order. The base plate may be made of aluminum or glass. The underlying layer may be made of a Co—Cr alloy. The protection film may be a diamond like carbon (DLC) layer. The lubrication layer may be formed by organic liquid lubricant having a main chain of perfluoropropylene and an end group of hydroxyl group (—OH) or benzene ring. 
         [0029]      FIG. 2A  is a plan view of the head stack assembly  20 . In the following description, the short-side direction of the head stack assembly  20  is defined as an X-axis direction, and the long-side direction thereof is defined as a Y-axis direction.  FIG. 2B  is the head stack assembly  20  viewed from the +X direction to the −X direction. 
         [0030]    As illustrated in  FIGS. 2A and 2B , the head stack assembly  20  has a housing part  30 , a fork part  32 , a coil  34 , three carriage arms  36 A,  36 B and  36 C, four head sliders  16 A,  16 B,  16 C and  16 D, and ahead IC  52 . The housing part  30  has a cylindrical shape. The fork part  32  is fixed to an end of the housing part  30  on the −Y side. The coil  34  is held by the fork part  32 . The three carriage arms  36 A,  36 B and  36 C are fixed to the housing part  30  at given intervals in the height direction (Z-axis direction). The four head sliders  16 A,  16 B,  16 C and  16 D are held by the three carriage arms  36 A,  36 B and  36 C. The head IC  52  is attached to a sidewall of the housing part  30 . The head stack assembly  20  is joined to the enclosure  10  via a bearing member  18  provided in the center of the housing part  30  so as to be free to rotate about the Z axis. A voice coil motor  50  is composed of the coil  34  of the head stack assembly  20  and a magnetic unit  24  (fixed to the enclosure  10 ) including a permanent magnet depicted in  FIG. 1 . The voice coil motor  50  drives the head stack assembly  20  to swing about the bearing shaft  18 , as indicated by a one-dotted chain line in  FIG. 1 . 
         [0031]    The carriage arms  36 A- 36 C may be shaped by punching a stainless plate or extruding an aluminum member. As depicted in  FIG. 2A , elliptic holes  36 Aa- 36 Ca, which function as first engagement parts or arm-side engagement parts, are respectively formed in the carriage arms  36 A- 36 C. It can be seen from  FIG. 2A  and  FIGS. 3A through 3C  that V-shaped grooves or slits  36 Ab- 36 Cb are formed on sidewalls of the carriage arms  36 A through  36 C on the +X side. 
         [0032]    As depicted in an exploded perspective view of  FIG. 3A , the head slider  16 A is provided on a lower surface side of an end portion of a head suspension  40 A on the +Y side. The head suspension  40 A is attached to the carriage arm  36 A through a base plate  38 A. As depicted in an exploded perspective view of  FIG. 3B , the head slider  16 B is provided on an upper surface side of an end portion of a head suspension  40 B on the +Y side, which is attached to the carriage arm  36 B through a base plate  38 B. Similarly, the head slider  16 C is provided on a lower surface side of an end portion of a head suspension  40 C on the +Y side, which is attached to the carriage arm  36 C through a base plate  38 C. As depicted in an exploded perspective view of  FIG. 3C , the head slider  16 D is provided on an upper surface side of an end portion of a head suspension  40 D on the +Y side, which is attached to the carriage arm  36 D through a base plate  38 D. The head sliders  16 A and  16 B face each other in the vertical (Z-axis) direction across the magnetic disk  12 A, and the head sliders  16 C and  16 D face each other in the vertical (Z-axis) direction across the magnetic head  12 B. 
         [0033]    The head sliders  16 A through  16 D have respective recording/reproduction heads including recording elements and reproduction elements. Each recording element utilizes the magnetic field generated by a thin-film coil pattern to write data on the magnetic disk  12 A (or  12 B). Each reproduction element reads data from the magnetic disk  12 A (or  12 B) and may be a giant magneto-resistive (GMR) element utilizing resistance change of a spin-valve film or may be a tunnel junction magneto-resistive (TMR) element utilizing resistance change of a tunnel junction film. 
         [0034]    The head suspensions  40 A through  40 D respectively support the head sliders  16 A through  16 D in a cantilever fashion due to gimbal springs (not depicted) at ends of the head suspensions  40 A through  40 D on the +Y sides. Pressing force from the head suspension  40 A is exerted on the head slider  16 A towards the front or back surface of the magnetic disk  12 A. When the magnetic disk  12 A rotates, ascending force is exerted on the head slider  16 A due to the function of airflow that is generated on the surface of the magnetic disk  12 A and is dependent on the rotation. The head slider  16 A continues to fly with a relatively high rigidity during rotation of the magnetic disk  12 A while the ascending force is balanced with the pressing force described above. Each of the other head suspensions  40 B,  40 C and  40 D has the same function as that of the head suspension  40 A. The head stack assembly  20  swings about the bearing member  18  when the head sliders  16 A through  16 D are flying, so that the recording/reproduction heads can be positioned on desired recording tracks on the magnetic disks  12 A and  12 . 
         [0035]    As illustrated in  FIGS. 2A and 2B , the head IC  52  is mounted on a flexible board  59  to which wiring patterns and terminals  53  are fixed on the +X side of the housing part  30 . A flexible connector (not illustrated) connected to a printed circuit board of the HDD  100  is connected to the flexible board  59 . The head IC  52  is electrically connected to a hard disk controller on the printed circuit board. 
         [0036]    Ends of signal relay members (long tails)  55 A through  55 D are respectively connected to the terminals  53  on the flexible board  59 . The other ends of the signal relay members  55 A through  55 D are respectively connected to the head sliders  16 A through  16 D. The signal relay members  55 A through  55 D may be formed by a stainless thin plate that may, for example, be 20 μm thick. Signal lines are formed, in the form of a thin film, on an insulating film on a surface of the stainless thin plate. The magnetic head and the head IC communicate with each other through the signal lines. As illustrated in  FIG. 2A , the signal relay members  55 A through  55 D are pressed against the sidewall portions (V-shaped grooves or slits) of the carriage arms  36 A through  36 C on the +X side by means of pressure members  60 A through  60 C. 
         [0037]      FIG. 4  is a perspective view of the presser members  60 A through  60 C. Each of the presser members  60 A through  60 C may be made of, for example, resin and has an approximately H-shaped X-Z cross section. More particularly, each of the presser members  60 A through  60  has a projection  72 , a pair of arms  74 A and  74 B, and tab portions  78 A and  78 B. The projection  72 , which is an exemplary structure of a fitting portion of the presser member, has an X-Z cross section shaped into an approximately isosceles triangle and extends in the Y-axis direction. The projection  72  functions as an engagement or fitting portion. The paired arms  74 A and  74 B are symmetrically arranged vertically across the projection  72 . The tab portions  78 A and  78 B are respectively formed on the +X sides of the arms  74 A and  74 B. 
         [0038]    The projection  72  has a first surface  72   a  (on the +Z side) in the Y-axis direction, and a second surface  72   b  (on the −Z side) in the Y-axis direction. The projection  72  has a shape that is fitted into any of the grooves  36 Ab through  36 Cb respectively provided in the carriage arms  36 A through  36 C. 
         [0039]    A craw portion  76 A serving as a second engagement part is provided in an end of the arm  74 A on the −X side. The craw portion  76 A protrudes from the arm  74 A in the −Z direction. A craw portion  76 B serving as another second engagement part is provided in an end of the arm  74 B on the −X side. The craw portion  76 B protrudes from the arm  74 B in the X direction. The craw portions  76 A and  76 B are symmetrically arranged in the vertical direction (Z-axis direction). 
         [0040]    The tab portion  78 A has an upper surface that is flush with the upper surface of the arm  74 A and is provided at the +X side of the projection  72 . The tab portion  78 B has a lower surface that is flush with the lower surface of the arm  74 B and is provided at the +X side of the projection  72 . 
         [0041]    The presser members  60 A through  60 C thus configured are respectively attached to the carriage arms  36 A through  36 C as described below. 
         [0042]    The presser member  60 A is attached to the carriage arm  36 A, as depicted in  FIG. 5A . The signal relay member  55 A is arranged in the groove  36 Ab of the carriage arm  36 A. In this state, the presser member  60 A is moved in a direction indicated by an arrow A. In this movement, the arms  74 A and  74 B of the presser member  60 A are elastically deformed. Then, as depicted in  FIG. 5B , the craw portions  76 A and  76 B engage with or hook up corners (edges) of the elliptic hole  36 Aa, so that the presser member  60 A can be fixed to the carriage arm  36 A. In the fixed state, as depicted in  FIG. 5B , the signal relay member  55 A is interposed between the second or lower surface  72   b  of the projection  72  and the corresponding surface of the carriage arm  36 A that defines the groove  36 Ab. Thus, the signal relay member  55 A is fixedly held between the presser member  60 A and the carriage arm  36 A. 
         [0043]    Similarly, the presser member  60 B is attached to the carriage arm  36 B, as depicted in  FIG. 5C . The presser member  60 B is moved in the direction A in a state in which the signal relay members  55 B and  55 C are arranged in the groove  36 Bb of the carriage arm  36 B. As depicted in  FIG. 5D , the craw portions  76 A and  76 B of the presser member  60 B hook up corners (edges) of the elliptic hole  36 Ba, so that the presser member  60 B can be fixed to the carriage arm  36 B. In the fixed state, as depicted in  FIG. 5B , the signal relay member  55 B is interposed between the first surface  72   a  (upper surface) of the projection  72  and the corresponding surface of the carriage arm  36 B that defines the groove  36 Bb. Further, the signal relay member  55 C is interposed between the second surface  72   b  (lower surface of the projection  72  and the corresponding surface of the carriage arm  36 B that defines the groove  36 Bb. Thus, the signal relay members  55 B and  55 C can be fixedly held between the presser member  60 B and the carriage arm  36 B. 
         [0044]    Similarly, the presser member  60 C is attached to the carriage arm  36 C, as depicted in  FIG. 5E . The presser member  60 C is moved in the direction A in a sate in which the signal relay member  55 D is arranged in the groove  36 C of the carriage arm  36 C. As depicted in  FIG. 5F , the craw portions  76 A and  76 B of the presser member  60 C hook up corners (edges) of the elliptic hole  36 Ca, so that the presser member  60 C can be fixed to the carriage arm  36 C. In the fixed state, as depicted in  FIG. 5F , the signal relay member  55 D is interposed between the first surface  72   a  of the projection  72  and the corresponding surface of the carriage arm  36 C that defines the groove  36 Cb. Thus, the signal relay member  55 D can be fixedly held between the presser member  60 C and the carriage arm  36 C. 
         [0045]    In the present embodiment, as depicted in  FIG. 6 , the signal relay members  55 B and  55 C are located at the opposite sides of the projection  72 . Thus, a read signal line may be arranged in an area  93  of the signal relay member  55 B indicated by a circle of a broken line, and a write signal line may be arranged in another area  94  of the signal relay member  55 B. Similarly, a write signal line may be arranged in an area  95  of the signal relay member  55 C, and a read signal line may be arranged in another area  96  of the signal relay member  55 C. Even in the above arrangement, it is possible to prevent the read and write signal lines in each signal relay member from being extremely close to each order or laying on each other. It is thus possible to restrain crosstalk or injection from the write and read signal lines in each signal relay member and to prevent the heads from being deteriorated or damaged due to excessive current that flows through the heads. 
         [0046]    A description will now be given of a way to detach the presser members  60 A through  60 C from the carriage arms  36 A through  36 C. 
         [0047]    As illustrated in  FIG. 7A , the tab portions  78 A and  78 B receive forces in directions indicated by arrows B so as to be urged closer to each other. Thus, by the principle of leverage having a fulcrum O, the arms  74 A and  74 B are deformed so as to increase the distance between the craw portions  76 A and  76 B. 
         [0048]    Thus, the presser members  60 A through  60 C can be detached from the carriage arms  36 A through  36 C by applying forces to the tab portions  78 A and  78 B in the directions B and forces thereto in the direction C, as illustrated in  FIG. 7A .  FIG. 7B  depicts a state in which the presser members  60 A through  60 C are completely detached from the carriage arms  36 A through  36 C. The forces applied in the directions B disengage the craw portions  76 A and  76 B from the elliptic holes  36 Aa through  36 Ca. The forces applied in the direction C move the presser members  60 A through  60 C in the +X direction. 
         [0049]    In the present embodiment, in the fabrication process of the HDD  100 , the head performance is inspected after the head stack assembly  20  is assembled. If it is determined that the head performance is not good by the inspection, the head sliders  16 A through  16 D and the signal relay members  55 A through  55 D are removed from the carriage arms for the purpose of replacement with new ones. The presser members  60 A through  60 D can easily be detached from the carriage arms  36 A through  36 C only by applying forces thereto in the directions B and C, as illustrated in  FIG. 7A . Thus, the signal relay members can be replaced with the presser members  60 A through  60 D being detached. As compared to fixing of the signal relay members by an adhesive or the like, detachment and replacement of the signal relay members can be carried out easily. 
         [0050]    As described above, according to the present embodiment, the signal relay members  55 A through  55 D are held with pressure by fitting the projections  72  of the presser members  60 A through  60 C into the grooves  36 Ab through  36 Cb of the carriage arms  36 A through  36 C. That is, the signal relay members  55 A through  55 D are interposed between the carriage arms  36 A through  36 C and the presser members  60 A through  60 C. It is thus possible to prevent the signal relay members  55 A through  55 D from moving and causing displacement. Further, it is possible to restrain the signal relay members  55 A through  55 D from vibrating. The presser members  60 A through  60 C are fixed to the carriage arms  36 A through  36 C by engaging the craw portions  76 A and  76 B with the elliptic holes  36 Aa through  36 Ca Thus, the presser members  60 A through  60 C can be disengaged and detached easily. It is thus possible to easily replace the signal relay members  55 A through  55 C with new ones. The projections  72  are shaped into isosceles triangles, and the grooves  36 Ab through  36 Cb have corresponding V-shaped cross sections. It is thus possible to easily fit the projections  72  into the grooves  36 Ab through  36 Cb. Further, it is possible to fixedly hold the signal relay members  55 A through  55 D in collaboration with the projections  72  and the grooves  36 Ab through  36 Cb even if these members have some differences introduced in manufacturing. 
         [0051]    The HDD  100  of the present invention has improved head positioning due to suppressed vibration of the signal relay members  55 A through  55 D. It is thus possible to more reliably write data on the magnetic disks  12 A and  12 B and read data therefrom and to improve the data recording density. The easy replacement work of the signal relay members makes it possible to quickly recover the HDD  100  from initial defect or failure. 
         [0052]    In the present embodiment, the two signal relay members  55 B and  55 C are fixedly held by using the first surface  72   a  (on the +Z side) of the projection  72  and the second surface  72   b  (on the −Z side) thereof. It is thus possible to keep the read and right signal lines in each signal relay member away from each other and to prevent the occurrence of crosstalk therebetween. This makes it possible to prevent the heads from being deteriorated or damaged due to excessive current that flows through the heads. 
         [0053]    The presser members  60 A through  60 C are fixed to the carriage arms  36 A through  36 C by engaging the craw portions  76 A and  76 B with the elliptic holes  36 Aa through  36 Ca. With this simple structure, the presser members  60 A through  60 C can be attached to the carriage arms  36 A through  36 C. 
         [0054]    The presser members  60 A through  60 C have the tab portions  78 A and  78 B for widening the distance between the craw portions  76 A and  76 B. Thus, the presser members  60 A through  60 C can be easily disengaged with and detached from the carriage arms  36 A through  36 C. 
         [0055]    The present embodiment employs the combination of the projections  72  shaped into approximately isosceles triangles and the grooves  36 Ab through  36 Cb shaped into approximately V-shaped cross sections. The present invention is not limited to the above combination. For example,  FIG. 8A  illustrates another combination of a projection  72 ′ shaped into an approximately C-shaped contour in cross section and a groove  36   b ′ shaped into an approximately C-shaped cross section. This combination brings about the same effects as described before.  FIG. 8B  illustrates yet another combination of a projection  72 ″ shaped into an approximately U-shaped or curved contour in cross section and a groove  36   b ″ shaped into approximately U-shaped or curved cross section. This combination brings about the same effects as described before. The curved contour or cross section makes it possible to hold the signal relay members in a curved state and to improve the rigidity of the signal relay members. This contributes to suppressing vibration of the signal relay members. 
         [0056]    In the present embodiment, the carriage arms  36 A through  36 C have the grooves  36 Ab through  36 Cb, and the presser members  60 A through  60 C have the projections  72 . The present invention is not limited to the above arrangement.  FIG. 9A  illustrates a variation having a carriage arm  36 ′ with a projection  99 , and a presser member  60 ′ with a groove  79 . As depicted in  FIG. 9B , the signal relay members can be held between the projection  99  and the groove  79 . The presser member  60 ′ can be detached from the carriage arm  36 ′ by the simple manner so that the signal relay members can be replaced easily. The projection  99  may have an approximately C-shaped or U-shaped contour in cross section, and the groove  79  may have a corresponding cross section. 
         [0057]    In the present embodiment, the craw portions  76 A and  76 B of the presser members  60 A through  60 C are engaged with the elliptic holes  36 Aa through  36 Ca of the carriage arms  36 A through  36 C. However, the present invention is not limited to the above structure.  FIG. 10A  illustrates a variation in which engagement grooves  86 A and  86 B are respectively formed on the upper (+Z side) and lower (−Z side) surfaces of each of the carriage arms  36 A through  36 C. As illustrated in  FIG. 10B , the craw portions  76 A and  76 B are respectively engaged with the grooves  86 A and  86 B so that the presser member  60 A through  60 C can be fixed to the carriage arms  36 A through  36 C, respectively. With the above structure, the arms  74 A and  74 B of the presser members  60 A through  60 C in the X-axis direction can be shortened and the weight of the head carriage arm  36 A through  36 C can be lightened. Further, the head positioning accuracy can be improved. 
         [0058]      FIG. 10C  illustrates yet another variation in which projections  88 A and  88 B are formed in each of the carriage arms  36 A through  36 C, and engagement arms  98 A and  98 B are formed in the arms  74 A and  74 B of each of the presser members  60 A through  60 C. With this structure, effects similar to those of the structures illustrated in  FIGS. 10A and 10B  can be obtained. It is possible to employ a further structure that fixes the presser members  60 A through  60 C to the carriage arms  36 A through  36 C by engaging parts of the presser members  60 A through  60 C with parts of the carriage arms  36 A through  36 C. 
         [0059]    As illustrated in  FIG. 11A , slits  43   a  and  43   b  may be formed in root portions of the tab portions  78 A and  78 B of each of the presser members  60 A through  60 C. Thus, the tab portions  78 A and  78 B may be removed by applying forces thereto in directions D when the head stack assembly  20  passes the head performance inspection after assembling. It is thus possible to light the weight of the head stack assembly  20  and reduce the influence of airflow caused by rotation of the magnetic disks  12 A and  12 B. The slits  43   a  and  43   b  may be applied to the presser member  60 ′ depicted in  FIGS. 9A and 9B . 
         [0060]    All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various change, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.