Abstract:
A small-volumed shock-cushioning structure SA of the present invention guarantees absorption of shocks of different magnitudes associated with two different states of a hard disk, and thereby to effectively protect the hard disk from the shocks of different magnitudes. The shock-cushioning structure SA includes a first shock-cushioning material CAL having a first stress-strain characteristic AL with a first effective cushioning stress, and a second shock-cushioning material CAH having a second stress-strain characteristic AH with a second effective cushioning stress greater than the first effective cushioning stress of the first stress-strain characteristic AL.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a shock-cushioning structure for holding a device susceptible to externally applied shocks and protecting the device by absorbing shocks applied thereto. More particularly, the present invention relates to a shock-cushioning structure used for protecting a device vulnerable to shocks, e.g., a hard disk drive incorporated in a notebook computer.  
         [0003]     2. Description of the Background Art  
         [0004]     In recent years, a wide range of information processing apparatuses, including a notebook computer, have become lighter, smaller, and thinner, while achieving higher performance and larger capacity. In order to satisfy the needs of higher performance and larger capacity, an information processing apparatus has incorporated therein a high-density and high-precision hard disk drive (hereinafter, simply referred to as a “hard disk”) as a storage device. In order to extend storage capacity or protect security of stored information, the hard disk might be frequently attached to or detached from the information processing apparatus. Moreover, the detached hard disk might be carried by itself or kept separate from the information processing apparatus.  
         [0005]     Accordingly, in the case of carrying the information processing apparatus, shock and vibration transmitted into the information processing apparatus might damage the hard disk held within the information processing apparatus. Further, in the case where the hard disk is carried by itself, rather than held in the information processing apparatus, the hard disk might directly undergo shock and vibration, and therefore might be damaged more severely. Furthermore, even if the hard disk is kept in storage, the hard disk might be damaged due to unexpected shock and vibration, depending on the circumstance in which it is kept in storage.  
         [0006]     In order to avoid the problems as described above, various contrivances are employed for minimizing shock and vibration caused to the hard disk, thereby preventing the hard disk from being damaged regardless of whether the hard disk is held in the information processing apparatus.  
         [0007]     Because of the ease of portability, the information processing apparatus as described above is widely used indoor and outdoor. In such usage, it is variable as to where and how the information processing apparatus is used. Accordingly, the information processing apparatus might be bumped by mistake against a hard object during carriage, might be roughly placed on a table or the like, or might be dropped from the table when it is used or not. In such a situation, the hard disk held inside as a storage device might be damaged by shock and/or vibration transmitted into the information processing apparatus.  
         [0008]     A variety of shock-cushioning structures have been proposed for absorbing externally applied shock and/or vibration as described above, thereby protecting the hard disk. Although the proposed shock-cushioning structures are provided in a variety of shapes, they have a common basic structure in that a jacket, which is formed by an elastic material functioning as a cushion, covers the outer edge of the hard disk, and deforms itself in response to externally applied shocks, thereby absorbing and buffering the shocks.  
         [0009]     The above-mentioned common structure of conventional shock-cushioning structures and an information processing apparatus employing such a common structure are described below with reference to  FIGS. 14, 15 ,  16 , and  17 .  
         [0010]      FIG. 14  shows an information processing apparatus having incorporated therein a hard disk held by a conventional and common shock-cushioning structure. In  FIG. 14 , for the sake of illustration, a hard disk storage section  1   c  of an information processing apparatus Dpp is shown with its flip-up lid L open. The information processing apparatus Dpp includes a keyboard  4  provided on the rear side of a housing  1 , and the storage section  1   c  provided on the front side for storing detachable elements, such as a hard disk. The storage section  1   c  stores a main circuit board  2  and a hard disk unit SU in which a hard disk is held by a shock-cushioning structure. Note that the hard disk unit SU is connected to the main circuit board  2  via a signal cable  6  in a freely movable manner. The flip-up lid L is provided as an upper face of the storage section  1   c.  Further, a display section  5  is provided on an upper edge of the housing  1  in such a manner as to be freely open and closed.  
         [0011]      FIG. 15  shows a structure of the hard disk unit SU. The hard disk unit SU includes a hard disk  3 , a shock-cushioning structure  51 , and a cover  52 . The shock-cushioning structure  51  is made of a low-rigidity and low-repulsive material, and has a box-like shape with a recess portion  51   c  adapted to the shape of the hard disk  3 . The cover  52  is made of the same material as the shock-cushioning structure  51 , and has a flat plate-like shape.  
         [0012]     In the hard disk unit SU, the hard disk  3  is accommodated in the recess portion  51   c  of the shock-cushioning structure  51 , and the cover  52  is fitted into the recess portion  51   c  so as to hold the hard disk  3 . Note that the signal cable  6  of the hard disk  3  extends out of the hard disk unit SU from between the shock-cushioning structure  51  and the cover  52 , and is connected to the main circuit board  2  as described above.  
         [0013]      FIG. 16  shows a state of the hard disk unit SU when the information processing apparatus Dpp undergoes shock from the side. If the shock is applied to the housing  1  of the information processing apparatus Dpp from a direction of arrow Fa, an impact force is generated so as to move the hard disk  3  along an Fr direction which is opposite to the Fa direction. However, the shock-cushioning structure  51  and the cover  52  are made of a low-rigidity and low-repulsive material, and therefore when the hard disk  3  moves along the Fr direction, the shock-cushioning structure  51  deforms itself in the vicinity of a side face  3   a  of the hard disk  3 , thereby absorbing the impact force acting on the hard disk  3 . Such deformation of the shock-cushioning structure prevents the hard disk  3  from being damaged by the shock.  
         [0014]     Note that when implementing capacity extension or security protection, the hard disk unit SU may be detached from the housing  1  or only the hard disk  3  may be detached from the shock-cushioning structure  51  and the cover  52 .  
         [0015]     As described above, in the conventional shock-cushioning structure, the shock-cushioning structure  51  deforms itself in a portion, which is in contact with the hard disk  3  moved due to shock, thereby absorbing an impact force acting on the hard disk  3  at a prescribed rate. However, the impact force to be withstood by the hard disk  3  varies depending on its operation status. Specifically, in the case where the information processing apparatus is in use, a shock-withstanding capability of the hard disk  3  is different between when the hard disk  3  is in operation and when the hard disk  3  is not in operation. When the hard disk  3  is not in operation, a magnetic head is on standby on a non-recording surface, and the hard disk  3  is able to withstand shock even if a relatively large impact force is applied thereto. On the other hand, when the hard disk  3  is in operation, the magnetic head is located above a platter, and the hard disk  3  might be damaged even by a small shock. Accordingly, the magnitude of an impact force to be absorbed by the shock-cushioning structure  51  is considerably different between when the hard disk  3  is in operation and when the hard disk  3  is not in operation.  
         [0016]     Referring to  FIG. 17 , descriptions are provided with respect to the magnitude of an impact force to be absorbed and a required shock absorption characteristic of the shock-cushioning structure. In  FIG. 17 , the horizontal axis indicates height of fall of a hard disk corresponding to shock applied to the hard disk, and the vertical axis indicates a shock value G at which the safety of the hard disk is guaranteed. Curve L 1  indicates variations of the shock value at which the safety of the hard disk not in operation is guaranteed, and curve L 2  indicates variations of the shock value at which the safety of the hard disk in operation is guaranteed.  
         [0017]     Here, it is assumed that the hard disk in operation is guaranteed to withstand a shock caused in the case of a fall from a height of up to 60 centimeters (cm) and the hard disk not in operation is guaranteed to withstand a shock caused in the case of a fall from a height of up to 80 cm. It is appreciated from  FIG. 17  that a shock caused in the case of a fall from a height of 60 cm is approximately 200 G, and a shock caused in the case of a fall from a height of 80 cm is approximately 700 G.  
         [0018]     Accordingly, a value of shock to be absorbed when the hard disk is in operation is approximately 200 G, a value of shock to be absorbed when the hard disk is not in operation is approximately 700 G, and there is a considerable difference between the values of shock to be absorbed. The shock-cushioning structure deforms itself to absorb shock, and therefore if the ratio of absorption deformation to shock is constant, the shock-cushioning structure is required to shrink and deform itself in relation to the magnitude of the shock. However, in order to realize a lighter, smaller, and thinner information processing apparatus, it is necessary to reduce the size of the shock-cushioning structure for protecting the hard disk from the shock, so that the amount of shrinkage and deformation is restricted. Under such a circumstance where the amount of shrinkage and deformation is restricted, it is necessary to reduce the amount of deformation to shock in order to absorb a large shock which is required to be reliably absorbed when the hard disk is not in operation. In this case, it is necessary to select a harder shock-cushioning material. However, a hard shock-cushioning material for absorbing a large shock reflects a small shock equivalent to a shock which is required to be reliably absorbed when the hard disk is in operation, and therefore the small shockwave cannot be satisfactorily absorbed. Accordingly, if a space for accommodating the conventional shock-cushioning structure is limited, it is not possible to effectively protect the hard disk from shocks of two different shock values.  
       SUMMARY OF THE INVENTION  
       [0019]     Therefore, an object of the present invention is to provide a small-volumed shock-cushioning structure which guarantees absorption of shocks of different magnitudes associated with two different states of a hard disk, and thereby to effectively protect the hard disk from the shocks of different magnitudes.  
         [0020]     The present invention has the following features to attain the object mentioned above.  
         [0021]     A first aspect of the present invention is directed to a shock-cushioning structure formed by first and second shock-cushioning materials which are strained under impact stress to absorb the impact stress. The first shock-cushioning material has a first stress-strain characteristic with a first effective cushioning stress, and the second shock-cushioning material has a second stress-strain characteristic with a second effective cushioning stress greater than the first effective cushioning stress of the first stress-strain characteristic.  
         [0022]     Thus, despite its small volume, the shock-cushioning structure of the present invention is able to guarantees absorption of shocks of different magnitudes associated with two different states of the hard disk, and thereby to effectively protect the hard disk from the shocks of different magnitudes.  
         [0023]     These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]      FIG. 1  is a perspective view showing a configuration of a shock-cushioning structure according to a first embodiment of the present invention;  
         [0025]      FIG. 2  is a graph showing a shock absorption characteristic of the shock-cushioning structure shown in  FIG. 1 ;  
         [0026]      FIG. 3  is a perspective view showing a configuration of a shock-cushioning structure according to a second embodiment of the present invention;  
         [0027]      FIG. 4  is a graph showing a shock absorption characteristic of the shock-cushioning structure shown in  FIG. 3 ;  
         [0028]      FIG. 5  is a perspective view showing a configuration of a shock-cushioning structure according to a third embodiment of the present invention;  
         [0029]      FIG. 6  is a graph showing a shock absorption characteristic of the shock-cushioning structure shown in  FIG. 5 ;  
         [0030]      FIG. 7  is a perspective view showing a configuration of a shock-cushioning structure according to a fourth embodiment of the present invention;  
         [0031]      FIG. 8  is a perspective view showing a configuration of a shock-cushioning structure according to a fifth embodiment of the present invention;  
         [0032]      FIG. 9  is a graph used for explaining a basic feature of a shock-cushioning structure of the present invention;  
         [0033]      FIG. 10  is a view used for explaining how the shock-cushioning structure shown in  FIG. 3  is applied;  
         [0034]      FIG. 11  is a view used for explaining how a variation of the shock-cushioning structure shown in  FIG. 3  is applied;  
         [0035]      FIG. 12  is a view used for explaining how a variation of the shock-cushioning structure shown in  FIG. 8  is applied;  
         [0036]      FIG. 13  is a view used for explaining how a combination of shock-cushioning structures of the present invention is used;  
         [0037]      FIG. 14  is a perspective view showing an information processing apparatus having incorporated therein a hard disk held by a conventional shock-cushioning structure;  
         [0038]      FIG. 15  is an exploded view showing the shock-cushioning structure and the hard disk shown in  FIG. 14 ;  
         [0039]      FIG. 16  is a schematic view showing a state where shock applied to a hard disk is absorbed by the shock-cushioning structure shown in  FIG. 14 ; and  
         [0040]      FIG. 17  is a graph showing shock absorption characteristics of a shock-cushioning structure in relation to two shocks to be absorbed. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0041]     Firstly, a basic feature of a shock-cushioning structure of the present invention is described with reference to  FIG. 9 . In  FIG. 9 , the vertical axis indicates impact stress (Kfg/mm 2 ) applied to a shock absorption cushioning material, the horizontal axis indicates the amount (%) of strain of the shock absorption cushioning material corresponding to the impact stress, curve CL indicates a stress-strain characteristic of a low impact force absorption cushioning material, and curve CH indicates a stress-strain characteristic of a high impact force absorption cushioning material. From  FIG. 9 , it is appreciated that the low impact force absorption cushioning material is considerably strained even by a low impact stress, thereby protecting a hard disk in operation from a small shock, while the high impact force absorption cushioning material is merely slightly strained even by a high impact stress, thereby protecting a hard disk not in operation from a large shock.  
         [0042]     In general, it is known that an ideal cushioning material or structure under impact stress is characteristically deformed with a strain of up to about 70%. In the following descriptions, the range of the strain of up to about 70% is referred to as an “effective shock cushioning range Ra” of the cushioning material, and the range of impact stress, which can be absorbed in the effective shock cushioning range Ra, is referred to as an “effective cushioning stress Sa”. In  FIG. 9 , the effective cushioning stress Sa of a soft shock absorbing material AL having a low shock absorption characteristic CL is about 0.04 kgf/mm 2 , and the effective cushioning stress Sa of a hard shock absorbing material AH having a high shock absorption characteristic CH is about 0.19 kgf/mm 2 . Note that the effective cushioning stresses Sa of the soft and hard shock absorbing materials AL and AH are respectively referred to below as a “low effective cushioning stress SaL” and a “high effective cushioning stress SaH”.  
         [0043]     However, it is apparent that the soft shock absorbing material AL is suitable for an impact stress of about 0.04 kgf/mm 2  or less. Accordingly, the present invention provides a shock-cushioning structure by combining the soft and hard shock absorbing materials AL and AH, such that the soft shock absorbing material AL responds to a small shock applied to the hard disk in operation, while the hard shock absorbing material AH responds to a larger shock applied to the hard disk in operation.  
       First Embodiment  
       [0044]     A shock-cushioning structure according to a first embodiment of the present invention is described below with reference to  FIGS. 1 and 2 . In  FIG. 1 , arrow Fg indicates a direction of an impact stress applied to a shock-cushioning structure SA 1 . The shock-cushioning structure SA 1  includes a solid CALL formed by the soft shock absorbing material AL and a solid CAH 1  formed by the hard shock absorbing material AH. In  FIG. 2 , two dotted curves indicate the low and high shock absorption characteristics CL and CH as shown in  FIG. 9 , and solid line C 1  indicates a shock absorption characteristic of the shock-cushioning structure SA 1 .  
         [0045]     Specifically, in the shock-cushioning structure SA 1 , the soft shock absorbing material AL having the low shock absorption characteristic CL responds to an impact stress of about 0.04 Kgf/mm 2  or less, and the soft shock absorbing material AH having the high shock absorption characteristic CH responds to an impact stress of more than about 0.04 Kgf/mm 2  but not more than 0.19 Kgf/mm 2 . Note that at a strain of about 55%, the shock absorption characteristic C 1  of the shock-cushioning structure SA 1  is abruptly shifted from the low shock absorption characteristic CL to the high shock absorption characteristic CH. The reason for this is that the solids CAL 1  and CAH 1  are connected in a plane. Specifically, the shock-cushioning structure SA 1  is configured such that a shock of up to 0.04 Kgf/mm 2  is flexibly received by the solid CAL 1 , while a greater shock is securely received by the solid CAH 1 .  
         [0046]     Note that in a direction substantially parallel to the impact stress direction Fg shown in  FIG. 1 , a thickness TL 1  of the solid CAL 1  and a thickness TH 1  of the solid CAH 1  are suitably determined based on the size of a space in which the shock-cushioning structure SA 1  is accommodated and the amounts of strains of the solids CAH 1  and CAL 1 . In the following descriptions, the term “shock absorption characteristic transition range RT” is used to refer to a range around a strain of about 55% where a shock absorption characteristic C of a shock-cushioning structure SA is shifted from the low shock absorption characteristic CL to the high shock absorption characteristic CH. Note that a thickness T of the shock-cushioning structure SA 1  is equivalent to the sum of the thicknesses TL 1  and TH 1 .  
       Second Embodiment  
       [0047]     A shock-cushioning structure according to a second embodiment of the present invention is described below with reference to  FIGS. 3 and 4 . In  FIG. 3 , a shock-cushioning structure SA 2  includes a solid CAL 2  formed by the soft shock absorbing material AL and a solid CAH 2  formed by the hard shock absorbing material AH. The solid CAH 2  is similar in size to the above-described solid CAH 1 . Both of the solids CAL 2  and CAH 2  are formed in a wedge-like shape. A length TL 2   a  of a shorter side of the solid CAL 2  and a length TL 2   b  of a longer side of the solid CAL 2  are preferably represented by the following expressions (1) and (2), respectively. 
 
 TL 2 a=TL 1 −TH 1/2   (1) 
 
 TL 2 b=TL 1+ TH 1/2   (2) 
 
         [0048]     A length TH 2   a  of a longer side of the solid CAH 2  and a length TH 2   b  of a shorter side of the solid CAH 2  are preferably represented by the following expressions (3) and (4), respectively. 
 
 TH 2 a=T−TL 2 a    (3) 
 
 TH 2 b=T−TL 2 b    (4) 
 
         [0049]      FIG. 4  shows a shock absorption characteristic C 2  of the shock-cushioning structure SA 2 . In comparison with the shock absorption characteristic C 1  of the shock-cushioning structure SA 1  according to the first embodiment, the shock absorption characteristic C 2  of the shock-cushioning structure SA 2  varies moderately in the shock absorption characteristic transition range RT. Note that in order to cause the shock absorption characteristic C 2  to vary moderately in the shock absorption characteristic transition range RT, the relationships represented by the above expressions (1), (2), (3), and (4) do not necessarily require to be satisfied, and the shock absorption characteristic C 2  can be suitably determined based on a stress-strain characteristic and a shock absorption characteristic transition point of each of the soft and hard shock absorbing materials.  
       Third Embodiment  
       [0050]     A shock-cushioning structure according to a third embodiment of the present invention is described below with reference to  FIGS. 5 and 6 . In  FIG. 5 , similar to the shock-cushioning structure SA 2 , a shock-cushioning structure SA 3  includes a solid CAL 3  formed by the soft shock absorbing material AL and a solid CAH 3  formed by the hard shock absorbing material AH. The solids CAH 3  and CAL 3  have curved connection surfaces. Specifically, the connection surface of the solid CAH 3  is concave, and the connection surface of the solid CAL 3  is convex.  
         [0051]     A length TL 3   a  of a shorter side of the solid CAL 3  and a length TL 3   b  of a longer side of the solid CAL 3  are preferably represented by the following expressions (5) and (6), respectively. 
 
 TL 3 a≦TL 1− TH 1/2   (5) 
 
 TL 3 b=TL 1+ TH 1/2   (6) 
 
         [0052]     A length TH 3   a  of a longer side of the solid CAL 3  and a length TH 3   b  of a shorter side of the solid CAH 3  are preferably represented by the following expressions (7) and (8) ,respectively. 
 
 TH 3 a=T−TL 3 a    (7) 
 
 TH 3 b=T−TL 3 b    (8) 
 
         [0053]      FIG. 6  shows a shock absorption characteristic C 3  of the shock-cushioning structure SA 3 . In comparison with the shock absorption characteristic C 2  of the shock-cushioning structure SA 2  according to the second embodiment, the shock absorption characteristic C 3  of the shock-cushioning structure SA 3  is shifted more moderately from the low shock absorption characteristic CL to the high shock absorption characteristic CH. Note that in order to obtain the shock absorption characteristic C 3 , the relationships represented by the above expressions (5), (6), (7), and (8) do not necessarily require to be satisfied, and the shock absorption characteristic C 3  can be suitably determined based on a stress-strain characteristic and a shock absorption characteristic transition point of each of the soft and hard shock absorbing materials.  
       Fourth And Fifth Embodiments  
       [0054]     Shock-cushioning structures according to fourth and fifth embodiments of the present invention are described below with reference to  FIGS. 7 and 8 .  
         [0055]     As shown in  FIG. 7 , a shock-cushioning structure SA 4  according to the fourth embodiment is configured such that a solid CAL 4  formed by the soft shock absorbing material AL is parallel to and in contact with a solid CAH 3   r  formed by the hard shock absorbing material AH. Preferably, the solid CAL 4  is equivalent in size to the shock-cushioning structure SA 1 , and the solid CAH 3   r  has a shape similar to that of the solid CAH 3 . With this configuration, the solid CAL 4  formed by the soft shock absorbing material AL and the solid CAH 3   r  formed by the hard shock absorbing material are simultaneously strained in the shock absorption characteristic transition range RT, whereby it is possible to obtain a smoother shock absorption characteristic C 4  (not shown).  
         [0056]     In  FIG. 8 , a shock-cushioning structure SA 5  according to the fifth embodiment includes a solid CAL 5  formed by the soft shock absorbing material AL and a solid CAH 5  formed by the hard shock absorbing material AH. The solid CAL 5  has vertical trapezoidal faces in the impact stress direction Fg. The solid CAH 5  also has vertical trapezoidal faces in the impact stress direction Fg. As a result, the shock-cushioning structure SA 5  has a smoother shock absorption characteristic C 5  (not shown).  
         [0057]     Referring to  FIGS. 10, 11 ,  12 ,  13 , and  14 , a brief description is given below with respect to how the shock-cushioning structure of the present invention is applied. Firstly, an example of using the shock-cushioning structure SA 2  to absorb a shock applied to the hard disk  3  is described with reference to  FIG. 10 . In  FIG. 10 , the shock-cushioning structure SA 2  is applied such that the solid CAH 2  formed by the hard shock absorbing material AH is in contact with the hard disk  3 , and the solid CAL 2  formed by the soft shock absorbing material AL is in contact with the housing of a notebook personal computer, for example. This application of the shock-cushioning structure SA 2  is suitable for cushioning the shock applied to the hard disk  3  by catching the hard disk  3  using an area smaller than a catching area of the cushioning material (i.e., one entire surface of the shock-cushioning structure SA 2 ). Since the solid CAH 2  is hard, even if the hard disk  3  is caught by only a portion of the solid CAH 2 , the solid CAH 2  is able to deform itself entirely to absorb an impact of the hard disk  3  on the solid CAH 2 . The solid CAL 2  supports the solid CAH 2  by its entire connection surface with the solid CAH 2 , and therefore each of the solids CAH 2  and CAL 2  can be used to full advantage to cushion a shock applied to the hard disk  3 . Accordingly, it is possible to minimize a difference in degree of shock which occurs at the connection surface between the solids CAH 2  and CAL 2 , thereby obtaining a smooth two-phase shock absorption capability.  
         [0058]     On the other hand, in the case where the shock-cushioning structure SA 2  is applied such that the solid CAL 2  is in contact with the hard disk  3 , and the solid CAH 2  is in contact with the housing of the notebook personal computer, the solid CAL 2  is partially deformed by the hard disk  3  with which a portion of the solid CAL 2  is in contact. As a result, a shock cannot be transmitted to the solid CAH 2  through the entire connection surface between the solids CAL 2  and CAH 2  but through a portion of the connection surface. Accordingly, another shock occurs at the connection surface between the solids CAL 2  and CAH 2 . Since the solid CAL 2  is a soft shock absorbing material, the magnitude of shock which can be absorbed by the solid CAL 2  is smaller than the magnitude of shock which can be absorbed by the solid CAH 2 . Moreover, partial deformation of the solid CAL 2  reduces the shock absorption capability of the solid CAL 2 . That is, the solid CAL 2  cannot make full use of its shock absorption capability. Further, the entire shock-cushioning structure SA 2  cannot entirely make full use of its shock absorption capability.  
         [0059]     Similar to  FIG. 10 ,  FIG. 11  is used for explaining an example of using the shock-cushioning structure SA of the present invention to absorb a shock applied to the hard disk  3 . In this example, a solid SCH formed by a shock absorbing material harder than the solid CAH 2  is provided on the solid CAH 2  of the shock-cushioning structure SA 2  shown in  FIG. 10 . That is, the solid SCH is in contact with the hard disk  3 . Specifically, the solid SCH is connected to the solid CAH 2  which is connected to the solid CAL 2 , thereby forming a shock-cushioning structure SA 2 H. Accordingly, a shock applied to the hard disk  3  can be absorbed by making full use of the shock absorption capability of each of the solids SCH, CAH 2 , and CAL 2 . Further, the absorbed shock is transferred through entire connection surfaces of the solids SCH, CAH 2 , and CAL 2 . Accordingly, the shock-cushioning structure SA 2 H can make the full use of its entire shock-absorbing capability, while smoothly cushioning the shock in three phases, thereby reducing the shock applied to the hard disk  3 .  
         [0060]     It goes without saying that any shock-cushioning structure of the present invention can achieve an effect similar to effects achieved by the shock-cushioning structures SA 2  and SA 2 H described with reference to  FIGS. 10 and 11 , so long as the shock-cushioning structure is used such that its hard material side is in contact with a target object to be provided with cushioning against shocks, and its soft material side is in contact with a holding means such as a housing.  FIG. 12  shows exemplary usage of the shock-cushioning structure SA 5  shown in  FIG. 8  for achieving an effect similar to effects achieved by the shock-cushioning structures SA 2  and SA 2 H.  
         [0061]      FIG. 13  shows that the shock-cushioning structures SA described with reference to  FIGS. 10, 11 , and  12  are provided in a shock-cushioning container C for storing the hard disk  3 . As shown in  FIG. 13 , the shock-cushioning structures SA are provided in four corners of the shock-cushioning container C. Each shock-cushioning structure SA includes a hard solid CAH provided on the side to be brought into contact with the hard disk  3 , and a soft solid CAL provided on the side in contact with the shock-cushioning container C. Note that the shock-absorbing container C provided with the shock-cushioning structures SA as described above accommodates the hard disk  3  where indicated by two dotted chain lines. The shock-cushioning container C configured as described above is able to smoothly absorb externally applied shocks in multiple phases.  
         [0062]     As described above, the shock-cushioning structure of the present invention can be used for shock protection for a product vulnerable to shocks, e.g., a hard disk drive incorporated in a portable information apparatus typified by a notebook computer.  
         [0063]     While the invention has been described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is understood that numerous other modifications and variations can be devised without departing from the scope of the invention.