Abstract:
A shock and vibration isolation system for an article comprising a set of elastomers circumferentially positioned in a shear mode around a member carried by the article to simultaneously support the article and to isolate the article from shock and vibration by dissipation of energy through an internal shear action within the set of elastomers.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates generally to shock and isolation systems for shock sensitive articles and, more specifically, to shock and isolation system for disk drives that both support the disk drive and isolate the disk drive from external shock and vibration forces.  
         CROSS REFERENCE TO RELATED APPLICATIONS  
         [0002]    None.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0003]    None.  
         REFERENCE TO A MICROFICHE APPENDIX  
         [0004]    None  
         BACKGROUND OF THE INVENTION  
         [0005]    One of the difficulties with sensitive equipment such as computer disk drives is the need to provide effective isolation mounts that damp out shock and vibration forces to the disk drive yet allow the disk drive to be removed for servicing. Unfortunately, computer systems and disk drives need to mounted in areas that are subject to shock and vibration. The present invention allows one to mount a shock sensitive article such as a disk drive to effectively damp out vibrations and shocks thereto by circumferentially positioning a set of elastomers around a multi-faced member so that regardless of the orientation of the shock and vibration forces substantially all the elastomers are in a shear mode to thereby effectively damp out damaging shock or vibration forces.  
         SUMMARY OF THE INVENTION  
         [0006]    A shock and vibration isolation system for an article comprising a set of elastomers circumferentially positioned in a shear mode around a member carried by the article to simultaneously support the article and to isolate the article from shock and vibration by dissipation of energy through an internal shear action within the set of elastomers. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a perspective of a disk drive having a base member with a set of truncated pyramid shaped base members;  
         [0008]    [0008]FIG. 2 is a top view of one of the base members shown in FIG. 1;  
         [0009]    [0009]FIG. 3 is a front view of one of the base members shown in FIG. 1;  
         [0010]    [0010]FIG. 4 is an end view of one of the base members shown in FIG. 1;  
         [0011]    [0011]FIG. 5 is an elevation view of one of the elastomers for use in the present invention;  
         [0012]    [0012]FIG. 6 is a top view of a disk drive supported by a set of elastomers positioned in a shear mode;  
         [0013]    [0013]FIG. 7 is an end view of the disk drive of FIG. 6 showing the set of elastomers positioned in the shear mode; and  
         [0014]    [0014]FIG. 8 is a side view of the disk drive of FIG. 6 showing the support housing for mounting to a frame. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0015]    [0015]FIG. 1 is a perspective view of a disk drive mounted within a rectangular shaped housing  11  with a first elongated base  12  mechanically secured to one side of housing  11  by a set of three screws  13 . Similarly, a second base member  17  is secured to the opposite edge of housing  11  by a second set of three screws (not shown).  
         [0016]    Located on one end of base  12  is a truncated pyramid shaped member  14  and located on the opposite end of base  12  is a second truncated pyramid shaped member  15 . Similarly, located on the oppose side of housing  11  is a second base  17  which is identical to base  12  and also includes two truncated pyramid shaped members.  
         [0017]    Thus the two bases  12  and  17  are secured directly to opposite sides of the disk drive housing  11  to provide a rigid link thereto. One of the problems encountered with devices such as disk drives is that disk drives are partially vulnerable to frequencies in the range of 350 to 650 cycles per second. The shock and isolation system of the present invention has been found to provide effective isolation for frequencies in the range of 350 to 650 cycles per second to thereby minimize problems of disk failures  
         [0018]    [0018]FIG. 2 to FIG. 4 show a portion of base  12  with the truncated pyramid shaped member  14  extending outwardly therefrom. Member  14 , which is made from a rigid material such as metal, includes a first angled face  14   a , a second angled face  14   b , a third angled face  14   c  and a fourth angled face  14   d  with a top surface  14   e . The member  14  is secured to base  12  to provide a rigid link to the housing of disk drive  11 . In the embodiment shown each of the faces of the pyramid shaped member  14  form an angle ø of about 45 degrees with the base  12 .  
         [0019]    [0019]FIG. 5 is a perspective view of a cylindrical shaped elastomer  20  having a first end  21  and a second end  22  with a cylindrical shaped body  21 . Elastomer  20  preferable can be made from materials such as natural rubbers and synthetic resins such as polyvinyl chlorides, polyurethane, polyamides polystyrenes, copolymerized polyvinyl chlorides, and poloyolefine synthetic rubbers as well as synthetic materials such as urethane, EPDM, styrene-butadiene rubbers, nitrites, isoprene, chloroprenes, propylene, and silicones. The particular type of elastomeric material is not critical but urethane material sold under the trademark Sorbothane® is currently employed. Suitable material is also sold by Aero E.A.R. Specialty Composites, as Isoloss VL. The registrant of the mark Sorbothane® for urethane material is the Hamiltion Kent Manufactunng Company (Registration No. 1,208,333), Kent, Ohio 44240.  
         [0020]    [0020]FIG. 6 to FIG. 8 shows a disk drive housing  11  supported by four sets of elastomers  23 , each positioned in a shear mode on each of the four corners of the disk drive housing  11 . That is, located on one corner of disk drive  11  is a first support housing  25 , located on a second corner is a second support housing  26 , located on a third corner is a third support housing  27  and located on the fourth corner is a fourth support housing  28 . Each set of elastomers  23  is held in circumferential position surrounding a pyramid shape member by the respective support housing to provide both a static and dynamic support to the housing  11 . In the embodiment shown two elastomers are adhesively secured to tab  26   c , one is secured to tab  26   b , one is secured to tab  26   a  and two are secured to tab  26   d  with each of the ends of the elastomers extending inward to engage a face on the pyramid shaped member  14 . As a result, the circumferential spaced elastomers create a cup like engagement with the faces of the pyramid shaped member  14 . This provides a dual purpose, in the static mode the coaction supports the housing in a fixed position. In a dynamic condition the elastomers are allowed to flex and bend and absorb harmful shock and vibration energy through a shear mode to prevent damage to the disk drive which is secured to bases  12  and  17 .  
         [0021]    As each of the set of elastomers  23  and the support housings  25 ,  26 ,  27  and  28  are identical only one will be described herein. Support housing  26  includes a set of tabs  26   a ,  26   b ,  26   c  and  26   d  which cantileverly extend outward from a base  26   e  to form a cup-like circumferential housing for supporting an elastomer between the faces of pyramid shaped member  14  and the tabs of the housing  26 . Housing  26  includes a further extension or wing  26   f  for securing the support housing to a support frame or the like so that the support housings can both support and isolate the disk drive housing  11  from external shock and vibration.  
         [0022]    In order to illustrate the operation of the invention reference should be made to FIG. 9 which shows a partial cross sectional view taken along lines  9 - 9  of FIG. 6. FIG. 9 show the positioning of two of the individual cylindrical elastomers  20  and  20 ′ between the base truncated pyramid shaped member  14  and the support housing  26 . As all of the elastomers are similarly positioned with respect to the faces of the pyramid shaped members they will not be described herein. Elastomer  20  is positioned with one end  21  on surface  14   d  and the other end supported by tab  26   b . Similarly one end of elastomer  20 ′ has a first end  21 ′ positioned on face  14   c  and the opposite end in engagement with tab  26   b . The elastomer can be secured to the support housing by a suitable adhesive or the like. While the preferred embodiment discloses cylindrical elastomers, other shapes could be used as long as the elastomers are mounted in a shear mode. Likewise, the angled surface of the pyramid shaped members are preferably at an angle of 45 degrees; however, a greater or small angle could be used as long as the relationship between the support housing and the pyramidal shaped members ensures that the elastomers are in shear in response to a shock or vibration force.  
         [0023]    [0023]FIG. 9 illustrates how the member  14  is restrained from movement in both the upward and downward direction by the elastomers  20  and  20 ′. Restraint in the lateral direction is provided by the coaction of support housing  26  and  27 . Restraint in the direction into and out of the paper is provide by the elastomers secured to tab  26   a  and  26   b . As a result the elastomers coact to confine displacement of member  14  in three mutually perpendicular directions.  
         [0024]    In the embodiment shown elastomer  20  has a central axis  24  that extends normal to the surface  14   d  and tab  26   b . Similarly, elastomer  20 ′ has a central axis  24 ′ that extends normal to the surface  14   c  and tab  26   d . With the elastomer angularly positioned and held in circumferential position around pyramid shaped member  14  substantially all of elastomers are maintained in a shear condition to damp out the effects of external shocks or vibration. That is, a motion along axis  24  could produce a compression force in elastomer  20 ; however, the elastomer  20 ′ on the opposite side as well as all the other elastomers are maintained in a shear condition thus ensuring that the substantially all the forces are absorbed by shear within the elastomers. Thus the present invention maintains substantially all the elastomers in a shear condition to effective damp out shock and isolation forces by a three dimensional capture of the truncated pyramid shape member within the ends of the elastomers that extend convergently outward from the tabs of the support housing. In embodiment shown all of the elastomers are positioned in a shear mode when the disk drive is supported in a horizontal condition. While each of the faces of the multi-face members are shown as separate distinct faces the junctions between each of the faces of the multi-face member could be blended to provide a multi-faced member having a continuous surface.