Abstract:
The invention enables a magnetic disk drive to be inserted and removed against an attraction force exerted by a magnetic force that is strong enough to erase data on a magnetic disk enclosed within a metal case. A converting mechanism comprising a ballscrew and a ballscrew nut bracket is provided that converts rotational motion of a handle into translational motion of an HDD holder; by rotating the handle, the HDD holder with the hard disk drive mounted thereon is moved in the inserting and removing directions by overcoming the attraction force being exerted by the magnetic field generated by means of a permanent magnet. An electric motor may be used to generate the rotational force.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a data erasing apparatus for erasing data recorded on a magnetic disk(s) contained in a magnetic disk drive in order to prevent the risk of data leakage, etc. when scrapping or recycling the magnetic disk drive. 
     2. Description of the Related Art 
     To recycle non-defective magnetic disks used in magnetic disk drives rendered defective in the manufacturing process of magnetic disk drives, Japanese Unexamined Patent Publication No. 2001-331904 discloses a data erasing apparatus for erasing servo data written on a magnetic disk; this data erasing apparatus accomplishes data erasure by applying a magnetic field to the magnetic disk, with a portion thereof inserted between permanent magnets, while rotating the magnetic disk by driving the spindle motor in the disk drive. However, this apparatus is not suited as a data erasure apparatus for preventing data leakage when scrapping or recycling the magnetic disk, because it requires the step of exposing the magnetic disk outside the drive for data erasure, and because there is the possibility that the magnetic disk may not rotate due to failure. 
     Japanese Utility Model Registration No. 3088608 discloses a data erasing apparatus having a recessed section into which an entire hard disk drive can be inserted. To erase data on a magnetic disk with the magnetic disk enclosed within a metal housing, an even stronger magnetic field is required, but it is difficult to insert and remove the magnetic disk drive by overcoming the attraction force working in such a strong magnetic field. To solve this problem, the data erasing apparatus of Japanese Utility Model Registration No. 3088608 uses a magnetic field that is generated by energizing coils, and de-energizes the coils when inserting or removing the magnetic disk drive. However, this presents a problem in terms of ease of use, because the power supply for energizing the coils is always required, and because the operation for turning on and off the power supply has to be performed each time. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a data erasing apparatus that is suited to erase data when scrapping or recycling a magnetic disk drive, and that affords excellent usability. 
     According to the present invention, there is provided a data erasing apparatus for erasing data recorded on a magnetic disk contained in a magnetic disk drive, comprising: magnetic field generating means, having a space capable of accommodating the entire magnetic disk drive, for applying a magnetic field by means of a permanent magnet to the magnetic disk contained in the magnetic disk drive accommodated in the space; and a moving mechanism for moving the magnetic disk drive, in inserting and removing directions, in the space of the magnetic field generating means by overcoming an attraction force being exerted by the magnetic field. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view showing one example of a magnetic disk drive whose stored data is to be erased by a data erasing apparatus according to the present invention; 
         FIG. 2  is a diagram showing the basic construction of the data erasing apparatus of the present invention; 
         FIG. 3  is a diagram schematically showing a magnetic field generated in the data erasing apparatus of the present invention; 
         FIG. 4  is a perspective view of a data erasing apparatus according to a first embodiment of the present invention; 
         FIG. 5  is a perspective view showing the data erasing apparatus in a condition where a cover  61  shown in  FIG. 4  is removed; 
         FIG. 6  is a diagram showing an example in which shield plates  73  are provided; 
         FIG. 7  is a side view of the data erasing apparatus of  FIG. 5 ; 
         FIG. 8  is a side view showing the data erasing apparatus in a condition where upper and lower frames, side frame, and guide rail shown in  FIG. 7  are removed; 
         FIG. 9  is a plan view showing the data erasing apparatus with a magnetic disk drive accommodated therein; 
         FIG. 10  is a plan view showing a condition in which an HDD holder  76  is in a stop position; 
         FIG. 11  is a diagram for explaining how the HDD holder  76  is moved along guide frames  90  and  92 ; 
         FIG. 12  is a diagram for explaining how a handle is detached; 
         FIG. 13  is a perspective view of a data erasing apparatus according to a second embodiment of the present invention; 
         FIG. 14  is a perspective view showing the data erasing apparatus in a condition where a cover  102  shown in  FIG. 13  is removed; 
         FIG. 15  is a diagram showing an example in which shield plates  73  are provided; 
         FIG. 16  is a plan view showing the data erasing apparatus in a condition where an upper frame  62 , a yoke  46 , permanent magnets  42  and  44 , and side frames  66  and  68  shown in  FIG. 14  are removed; 
         FIG. 17  is a plan view showing a condition in which the HDD holder  76  is in a stop position; and 
         FIG. 18  is a perspective view showing the positional relationship between a block pad  124  and microswitches  128  and  129 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is an exploded perspective view showing one example of a magnetic disk drive whose stored data is to be erased by a data erasing apparatus according to the present invention. In  FIG. 1 , the magnetic disk drive  10  is hermetically sealed by an aluminum alloy base  12  and a cover  14 . A spindle motor  16  is mounted on the base  12 , and magnetic disks  18  are fixed to the spindle motor  16  via a clamp  20  with screws  22 . The number of magnetic disks  18  mounted is determined according to the specification of the magnetic disk drive, and the number of spacers  24  used is also determined accordingly. 
     The magnetic disks  18  are disk-shaped storage media for storing data thereon. Data is written to and read from the magnetic disks  18  by means of heads  28  attached to an actuator  26 . The actuator  26  is driven by a VCM  30 . 
       FIG. 2  is a diagram showing the basic arrangement and construction of permanent magnets in the data erasing apparatus of the present invention. As shown in  FIG. 2 , the construction of the data erasing apparatus  40  is such that a block consisting of permanent magnets  42  and  44  and a yoke  46  and another block consisting of permanent magnets  48  and  50  and a yoke  52  are mounted within a housing  54  into which a tray  56  is inserted in slidable fashion. 
     In  FIG. 2 , the space between the upper magnet block and the lower magnetic block forms a data erasing area  58  in which the entire magnetic disk drive  10  can be accommodated when erasing the data recorded on the magnetic disks  18  ( FIG. 1 ) in the magnetic disk drive  10 . The magnetic disk drive  10  is inserted into the data erasing area  58 , as shown in  FIG. 2 , for erasing the data recorded on the magnetic disks  18 . 
     The permanent magnet  42  is placed with its S pole facing up and N pole facing down in the figure, while the permanent magnet  44  is placed with its N pole facing up and S pole facing down. That is, the permanent magnets  42  and  44  are arranged adjacent each other with their magnetic poles attracting each other. Likewise, the permanent magnet  48  is placed with its N pole facing up and S pole facing down, while the permanent magnet  50  is placed with its S pole facing up and N pole facing down. That is, the permanent magnets  48  and  50  are also arranged adjacent each other with their magnetic poles attracting each other. 
     The permanent magnets  42 ,  44 ,  48 , and  50  function as magnetic field generating means. When the magnetic field generating means is viewed as a whole, unlike poles are arranged adjacent each other on both the upper and lower sides thereof. 
     The permanent magnets  42  and  48  are arranged opposite each other in the vertical direction with like poles facing each other. Similarly, the permanent magnets  44  and  50  are arranged opposite each other in the vertical direction with like poles facing each other. Accordingly, the permanent magnets  42  and  48  repel each other, and the permanent magnets  44  and  50  also repel each other. With this repulsion, the magnetic field formed in the data erasing area  58  is primarily in the horizontal direction. Accordingly, when the magnetic disk drive  10  is inserted in the data erasing area  58  as shown in  FIG. 2 , the direction of the magnetic field coincides with the direction of a tangent to each magnetic disk  18 . 
     The yoke  46  is mounted on the upper surfaces of the permanent magnets  42  and  44 . Likewise, the yoke  52  is mounted on the lower surfaces of the permanent magnets  48  and  50 . The functions of the yokes  46  and  52  are to enhance the magnetic flux density and to suppress unwanted magnetic flux leakage to the outside space. 
       FIG. 3  is a diagram schematically showing the generated magnetic field. The permanent magnets  42  and  48  arranged opposite each other in the vertical direction repel each other, and the permanent magnets  44  and  50  also repel each other. This repulsion results in the formation of a magnetic field in the horizontal direction. When the magnetic disks  18  are inserted horizontally into this area, the data stored thereon can be efficiently erased. 
     Since horizontal recording is employed for recording data on the magnetic disks  18 , it is desirable that a magnetic field in a direction horizontal to the magnetic disks  18  be used to erase the recorded data; further, it is required that the strength of the magnetic field be greater than the coercivity of the magnetic disks  18 . 
     To erase data recorded on magnetic disks with high coercivity, it is desirable that the permanent magnets  42 ,  44 ,  48 , and  50  be made of Nd—Fe—B based permanent magnets having high magnetic flux density. In  FIG. 3 , the magnetic field area where the magnetic field generated by the magnetic field generating means is directed horizontally is used for data erasure. When the magnetic disks are inserted horizontally into this magnetic field area, the data stored on the magnetic disks can be efficiently erased. 
     On the other hand, magnetic fluxes leaking from the permanent magnets  44  and  50  (N poles) return to the respective permanent magnets  42  and  48  (S poles) via the respective yokes  46  and  52 . This enhances the magnetic flux density and suppresses unwanted magnetic flux leakage to the outside space. For the yoke material, it is desirable to use a ferromagnetic material, for example, JIS SS400. 
     The data on the magnetic disks  18  is erased utilizing the above principle but, when the components forming the magnetic disk drive  10  are magnetic substances, it is difficult to pass the magnetic disk drive  10  into the data erasing area  58  because they are attracted to the magnets. 
     To address this problem and improve operability, the present invention includes a driving mechanism by which the magnetic disk drive is passed into the data erasing area  58  against the attraction forces of the magnets. 
       FIG. 4  is a perspective view of a data erasing apparatus  60  according to a first embodiment of the present invention, and  FIG. 5  is a diagram for explaining the internal construction of the data erasing apparatus  60  with a cover  61  removed from it. 
     As shown in  FIG. 5 , the permanent magnets  42  and  44  and the yoke  46  are mounted to an upper frame  62 , and the permanent magnets  48  and  50  (not shown) and the yoke  52  (not shown) are mounted to a lower frame  64 . The upper frame  62  and the lower frame  64  and mounted to side frames  66  and  68 , and the entire assembly is secured to a stand  72  mounted on a base  70 . 
     If the magnetic flux from the magnets heavily leaks outside the cover  61 , ill effects may be caused, for example, to precision instruments, causing them to malfunction. Therefore, shield plates  73  may be provided on the frames  62 ,  66 , and  68 , as shown in  FIG. 6 , to reduce the magnetic flux leaking outside. For the shield plates  73 , a material such as iron, silicon steel, or permalloy is used. 
     To describe the basic mechanism of the apparatus, when a handle  74  is rotated, an HDD holder  76  is caused to move rectilinearly into the space between the upper magnet block and the lower magnet block. 
       FIG. 7  is a side view of the data erasing apparatus  60 , and  FIG. 8  is a diagram for explaining the mechanism for moving the HDD holder  76  rectilinearly by the rotational motion of the handle  74 , with the upper and lower frames  62  and  64 , side frame  66 , stand  72 , guide rail  92 , and legs  93  removed for clarity. 
     In  FIG. 8 , the handle  74  is mounted via a gear  83  to a ballscrew  82  supported on bearing holders  78  and  80 . On the other hand, the HDD holder  76  is mounted via a support frame  84  on a ballscrew nut bracket  86  which is linked to the ballscrew  82 . In this construction, the HDD holder  76  is caused to move rectilinearly by the rotational motion of the handle  74 . The HDD holder  76  is provided with four engineering plastic bearings  88  which move along the grooves formed in the guide rails  90  and  92  ( FIG. 5 ). 
       FIG. 9  is a diagram showing the data erasing apparatus  60  loaded with the magnetic disk drive  10  whose stored data is to be erased. When the magnetic disk drive  10  is mounted on the HDD holder  76 , a stopper  94  attached to the guide rail  90  engages with a groove on the HDD holder  76  to hold it fixed in order to prevent the magnetic disk drive  10  from being drawn in by the strong magnetic force. Further, the support frame  84  is attached to the HDD holder  76  to fix the magnetic disk drive  10  in place after mounting it on the HDD holder  76 . 
     In operation, the handle  74  is rotated, causing the HDD holder  76  to move rectilinearly into the data erasing area  58  between the upper magnet block and the lower magnet block. 
     The HDD holder  76  moves with the engineering plastic bearings  88  ( FIG. 8 ) sliding along the grooves of the guide frames  90  and  92 , and stops at the position shown in  FIG. 10 . This is the position where the engineering plastic bearings  88  strike against the ends of the grooves of the guide frames  90  and  92 . From this position, when the handle  74  is rotated in the reverse direction, the HDD holder  76  is withdrawn from the space between the magnet blocks and moves back to the position shown in  FIG. 9 . 
     The above description has been given dealing with the case where the HDD holder  76  is moved using the ballscrew  82 , but the operation is similar if a trapezoidal screw is used. Other methods of moving the HDD holder  76 , using, for example, a timing belt, a rack and pinion, or a worm gear, are also possible. 
     Further, it is desirable that the apparatus be made compact for convenience of portability and, as shown in  FIG. 12 , the handle  74  is detachable and is fixed to the apparatus with a handle nut  75 . 
     As described above, the data recorded on the magnetic disks  18  is erased while the magnetic disk drive  10  mounted on the HDD holder  76  is being passed through the data erasing area  58  between the upper magnet block and the lower magnet block. 
       FIG. 13  is a perspective view of a data erasing apparatus  100  according to a second embodiment of the present invention, and  FIG. 14  is a diagram for explaining the internal construction of the data erasing apparatus  100  with a cover  102  removed from it. 
     The same component elements as those of the data erasing apparatus  60  described with reference to  FIGS. 4 to 12  will be designated by the same reference numerals, and the description thereof will not be repeated here. The difference from the data erasing apparatus  60  is that the HDD holder  76  is moved into and out of the space between the upper magnet block and the lower magnet block by means of a ballscrew  106  connected to an electric motor  104 . The assembly consisting of the upper and lower frames  62  and  64  and side frames  66  and  68  is mounted directly on the base  70 . Further, shield plates  73  may be provided on the frames  62 ,  66 , and  68 , as shown in  FIG. 15 , to reduce the magnetic flux leaking outside. 
       FIG. 16  is a diagram for explaining how the data recorded in the magnetic disk drive  10  is erased, with the permanent magnets  42  and  44 , yoke  46 , upper frame  62 , and side frames  66  and  68  removed for clarity. A shaft  108  of the electric motor  104  is connected to the ballscrew  106  by a coupling  109 . A ballscrew nut bracket  110  is mounted on the ballscrew  106 , and as the ballscrew  106  is rotated, the ballscrew nut bracket  110  moves rectilinearly. The HDD holder  76  is mounted on the ballscrew nut bracket  110 , so that the HDD holder  76  moves rectilinearly as the ballscrew  106  is rotated. Therefore, the entire construction is such that the HDD holder  76  moves rectilinearly as the shaft  108  of the electric motor  104  rotates. Shafts  112  and  114  are constructed as means for guiding the rectilinear movement of the HDD holder  76  while suppressing the wobbling thereof. 
     In operation, to erase the data recorded in the magnetic disk drive, first the magnetic disk drive  10  whose stored data is to be erased is mounted on the HDD holder  76 . In  FIG. 16 , a holder cover  116  ( FIG. 14 ) is removed for convenience of explanation. Next, a support plate  118  is attached to the HDD holder  76 . When a start button  120  is pressed, the electric motor  104  is rotated by a control circuit  122 . With this rotation, the HDD holder  76  moves rectilinearly, passing into the data erasing area  58  between the upper magnet block and the lower magnet block, and stops at the position shown in  FIG. 17 . 
     In the position of  FIG. 17 , a block pad  124  attached to the HDD holder  76  strikes against a microswitch  126 , whereupon the electric motor  104  rotates in the reverse direction, causing the HDD holder  76  to move backward. The HDD holder  76  again passes the magnet blocks and moves back to the position shown in  FIG. 16 . When the HDD holder  76  has moved back to the position shown in  FIG. 16 , the block pad  124  strikes against a microswitch  128 , whereupon the rotation of the electric motor  104  stops. 
       FIG. 18  is a diagram for explaining a sensor block for switching the direction of rotation of the electric motor  104  and for stopping the rotation of the electric motor  104 . As shown, by causing the block pad  124  attached to the HDD holder  76  to strike against the microswitch  128 , the rotation of the electric motor  104  is reversed or stopped. In the example of  FIG. 18 , two microswitches are used to ensure reliable operation by switching in the second microswitch  129  to replace the first microswitch  128  when the latter fails to operate. 
     The above description has been given for the case where the HDD holder  76  is moved using the ballscrew, but the operation is similar if a trapezoidal screw is used. Other methods of moving the HDD holder  76 , using, for example, a timing belt, a rack and pinion, or a worm gear, are also possible.