Abstract:
A case adapted for housing and protecting one or more stacked printed circuit boards and conforming with an industry small form factor specification. For a single printed circuit board, a cover includes sidewalls for encircling the printed circuit board and supports for attaching the printed circuit board thereto. The cover is keyed to and attached to a support element that may enclose the circuit board therewithin. One or more openings in the case provide access to external electrical connectors. For stacked printed circuit boards, a spacer supports a pair of printed circuit boards. A cover extends across the top of the spacer to enclose the printed circuit boards and screws extend through the cover into the spacer to secure these elements with one another. For additional printed circuit boards, further spacers, each supporting a printed circuit board are stacked between the first spacer and the cover.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to modular units for enclosing printed circuit boards, and, more particularly, to a case for enclosing stacked printed circuit boards.  
         [0003]     2. Description of Related Prior Art  
         [0004]     In the field of electronic equipment of various types, certain industry standards have been developed by the Electronic Industries Association (EIA) for the width and length of modular units housing various electronic equipment. Such standards may be referred to as form factor. In particular, these are EIA Specifications for Small Form Factor 63.5 mm (2.5″) disk drives and for Small Form Factor 88.9 mm (3.5″) disk drives.  
         [0005]     Printed circuit boards (hereinafter “PCBs”) are relatively densely populated with the relevant components but they are relatively fragile and may be damaged by rough handling during installation and replacement. Moreover, two or more PCBs may be required to satisfy the function and operation of an electric signal circuit of a particular electronic equipment. Furthermore, multiple PCBs may be used to obtain redundancy and the benefits resulting therefrom.  
         [0006]     When the single PCB or multiple PCBs are electrically interconnected to perform a specific function, many benefits are achieved by housing such a single PCB or multiple PCBs within a protective case. Such a case would expose the pins of one or more electrical connectors for electrical connection with ancillary circuitry and the like.  
       SUMMARY OF THE INVENTION  
       [0007]     A cover, which forms a case for a single printed circuit board (PCB) has at least one partly cutaway sidewall and the PCB includes one or more electrical connectors having pins accessible through the cutaway sidewall. The cover includes standard sized threaded apertures for attachment of the case to a support element. To house more than one PCB within the case, a spacer coincident with the boundary of the case, supports one or more PCBs. Depending upon the depth of the spacer and the height of the components mounted on the PCBs, the cover may be a flat plate secured to the spacer. To add further PCBs, additional spacers may be interconnected to support the added PCBs.  
         [0008]     Interconnection between two or more PCBs is provided by a pair of male/female electrical connectors disposed intermediate adjacent PCBs that are mechanically and electrically interconnected upon mounting of each additional PCB. The length and width of the case, irrespective of the number of stacked PCBs, conforms with an industry standard small form factor.  
         [0009]     It is therefore a primary object of the present invention to provide a case for one or any number of stacked PCBs.  
         [0010]     Another object of the present invention is to provide a case for stacked PCBs that conforms with an industry standard small form factor specifications.  
         [0011]     Yet another object of the present invention is to provide spacers for supporting one or more PCBs of a stack of PCBs disposed beneath a cover.  
         [0012]     Still another object of the present invention is to provide a case for stacking PCBs having spacers for supporting additional PCB and of a height commensurate with the components mounted on the respective PCB.  
         [0013]     A further object of the present invention is to provide an industry standard case attachable to a support element for housing one or more stacked PCBs.  
         [0014]     A yet further object of the present invention is to provide a method for mounting electrically interconnected PCBs within a case.  
         [0015]     A still further object of the present invention is to provide a method for housing one or any number of stacked PCBs within a case of specified dimensions.  
         [0016]     These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     The present invention will be described with greater specificity and clarity with reference to the following drawings, in which:  
         [0018]      FIG. 1  illustrates a cover for supporting a printed circuit board;  
         [0019]      FIG. 2  illustrates a top view of the cover shown in  FIG. 1 ;  
         [0020]      FIG. 3  is a top view of a printed circuit board located within the cover shown in  FIG. 1 ;  
         [0021]      FIG. 4  is a side view taken along lines  4 - 4 , as shown in  FIG. 3 ;  
         [0022]      FIG. 5  is a top view of the case;  
         [0023]      FIG. 6  is an end view taken along lines  6 - 6 , as shown in  FIG. 5 ;  
         [0024]      FIG. 7  is an exploded view illustrating two stacked printed circuit boards, a spacer and a flat cover;  
         [0025]      FIG. 8  illustrates a top isometric view of the assembly as shown in  FIG. 7 ;  
         [0026]      FIG. 9  is an end view taken along lines  9 - 9 , as shown in  FIG. 8 ;  
         [0027]      FIG. 10  is an exploded view showing three stacked printed circuit boards, two spacers and a flat cover;  
         [0028]      FIG. 11  is a top isometric view of the assembly shown in  FIG. 10 ;  
         [0029]      FIG. 12  is an end view taken along lines  12 - 12 , as shown in  FIG. 11 ;  
         [0030]      FIG. 13  is an exploded view illustrating four printed circuit boards, three spacers and a flat cover;  
         [0031]      FIG. 14  is a top isometric view of the assembly shown in  FIG. 13 ;  
         [0032]      FIG. 15  is an end view taken along lines  15 - 15 , as shown in  FIG. 14 ; and  
         [0033]      FIG. 16  is a representative underside exploded view of several printed circuit boards and spacers.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0034]     Referring to  FIGS. 1 and 2 , there is shown a cover  10  conforming with an industry small form factor specification (EIA specification). Sidewall  12  at one end includes an indentation  14  for providing access to a male electrical connector  16  mounted at the end of printed circuit board (PCB)  18 . A further indentation  20  may be located in end wall  22  to provide access to a male electrical connector  24  mounted on PCB  18 . As illustrated, three supports  30  are disposed adjacent the interior surface of sidewall  26 . Similar supports (not shown) are disposed adjacent the interior surface of sidewall  28 . PCB  18  is firmly attached to cover  10  by screws  32  penetrating corresponding apertures  34  in the PCB for threaded engagement with threaded apertures  36  respective supports  30 . A pair of bosses  54  may be disposed adjacent each sidewall  26 ,  28 . The bosses include threaded passageways  56  for engagement with screws to secure cover  10  to a support element.  
         [0035]     Cover  10  may be attached to a support element by screws engaging the lower part of threaded passageways  56  in bosses  54 . The cover further includes threaded passageways  57  in sidewalls  26 ,  28  for use in attaching cover  10  to a support element. Both of these modes of attachment are in accordance with the industry small form factor specification. Moreover, keys  40 ,  42  extend from sidewall  26  and similar keys, of which key  44  is shown in  FIG. 6 , extend from sidewall  28 .  
         [0036]     Referring jointly to  FIGS. 3, 4 ,  5  and  6 , various views of PCB  18  attached to cover  10  are illustrated. In particular,  FIG. 3  illustrates PCB  18  secured within cover  10  by a plurality of screws  32 . A plurality of recesses  55  are formed in PCB  18  to accommodate insertion of respective ones of bosses  54 . Additionally, access to electrical connectors  16  and  24  is through indentations  14 ,  20 , respectively, as shown.  FIG. 5  shows a top view of the assembly, which assembly conforms with the dimensions of an industry small form factor specification. As represented by rectangular line  53 , a label  59  or the like may be attached to the top surface of cover  10 .  FIG. 6  particularly illustrates case  58  formed by cover  10  containing PCB  18 . Access to electrical connector  16  is through indentation  14  in the cover.  
         [0037]     Referring jointly to  FIGS. 7, 8  and  9 , there is shown a first variant  60  of a case  61  for supporting stacked PCBs. A printed circuit board (PCB)  62  includes an electrical connector  64  attached to the underside thereof for mating engagement with a corresponding electrical connector external to the case. PCB  62  is secured to apertures  36  in the underside of supports  68  disposed along the interior surface of sidewalls  70 ,  72  of a spacer  74  by screws  76  penetrably engaging apertures  78  in the PCB. Upon such placement, the pins of electrical conductor  64  become located within indentation  80  in wall  82  of spacer  74 . A further PCB  84  rests upon each of supports  68  and is secured thereto by a plurality of screws  86  penetrably engaging apertures  88  in the PCB. Upon attachment of PCBs  62 ,  84  to spacer  74 , electrical connectors  90 ,  91  mounted on PCB  62  mechanically and electrically engage corresponding electrical connectors dependingly supported from PCB  84  (see  FIG. 16 ). To secure flat cover  92 , screws  96  penetrably engage apertures  98  in the cover and extend into threaded passageways  95  in bosses  94 . A label  100  may be attached to cover  92  for identification purposes.  
         [0038]     Upon assembly of the components illustrated in the exploded view shown in  FIG. 7 , the upper part of case  61  will look like the illustration shown in  FIG. 8 . In particular, the pins of electrical conductor  64  will be generally coincident with indentation  80  to permit interconnection with other equipment/electrical connectors. The circuitry attendant the stacked PCBs is completely protected and secured in such a manner as to be unlikely to be affected by vibration within whatever environment the case may be employed.  
         [0039]     Case  61  may be attached to a support element by screws engaging the lower part of threaded passageway  95  in bosses  94 . Spacer  74  includes further passageways  104  in sidewalls  70 ,  72  for use in attaching case  61  to a support element. Both of these modes of attachment are in accordance with the industry small form factor specification. Moreover, keys  106 ,  107  extend from sidewall  70  and similar keys, of which key  108  is shown in  FIG. 9  and key  109  is shown in  FIG. 16 , extend from sidewall  72 .  
         [0040]     Referring jointly to  FIGS. 10, 11  and  12 , second variant  110  of a case  111  for stackable printed circuit boards (PCBs) will be described. As the second variant includes elements in addition to those described above with respect to first variant  60  ( FIGS. 7, 8  and  9 ), common reference numerals will be used and the description of common elements will be relatively cursory. PCB  84  includes two or more electrical connectors  112 ,  113  extending upwardly therefrom. These electrical connectors mechanically and electrically interconnect with corresponding connectors dependingly supported from PCB  114  (see  FIG. 16 ). A further spacer  116  includes supports  118  attached to or formed as part of the interior surface of sidewalls  120 ,  122  of the spacer. Downwardly extending pins  124  extend from supports  118  at opposed corners of spacer  116 . These pins penetrably engage apertures  126  in PCB  84 . Thus, upon assembly, pins  124 , mating with apertures  126 , positionally stabilize PCB  84  and spacers  74  and  116  and cause it to rest upon and bear against supports  68  formed as part of spacer  74 . That is, the pins and corresponding apertures serve as registration elements to register spacers  74  and  116  with PCB  84 , thus removing stress on mating electrical connections between the printed circuit boards. A plurality of screws  128  extend through apertures  130  in PCB  114  for threaded engagement with respective ones of supports  118  formed as part of spacer  116 . Thereby, PCB  114  is secured to spacer  116 . A flat cover  92  rests upon spacer  116 . A plurality of elongated screws  132  extend through apertures  134  in cover  92 . These screws slide through respective ones of passageways  136  in bosses  138  and into threaded engagement with the upper end of respective one of passageways  95  in bosses  94 . A label  100  may be attached to cover  92  for identification purposes.  
         [0041]     Upon assembly, as described with respect to  FIG. 10 , case  111  will look like the case illustrated in  FIGS. 11 and 12 . It will contain three stacked PCBs and access to the pins of electrical connector  64  will exist through indentation  80 .  
         [0042]      FIGS. 13, 14  and  15  illustrate a third variant  150  of a case  151  for stackable printed circuit boards. As significant similarity exists between the second and third variants illustrated in  FIGS. 7, 8 ,  9 ,  10 ,  11  and  12 , common reference numerals will be used and the description of common elements will be relatively cursory. PCB  114  includes electrical connectors  152 ,  153  for mechanically and electrically interconnecting corresponding electrical connectors depending from PCB  154  (see  FIG. 16 ). A further spacer  156  includes supports  158  for supporting PCB  154  and this PCB is secured to the supports by screws  160  penetrating apertures  162  in the PCB and in threaded engagement with supports  158 . Supports  158  at diagonally opposed corners of spacer  156  include a downwardly depending pin  164  for engagement with a corresponding aperture  166  in PCB  114 . Thereby, PCB  114  is retained in place by these pins in the same manner as PCB  84  is retained in place by pins  124  extending from supports  118 . That is, the pins and corresponding apertures serve as registration elements to register spacer  156  with PCB  114 . Cover  92  is placed on the top of spacer  156  in juxtaposed relationship to PCB  154 .  
         [0043]     Cover  92  and spacers  74 ,  116  and  156  are secured to one another by elongated screws  168  extending through apertures  170  in cover  92 , passageways  172  in bosses  174  formed as part of spacer  156 , and into threaded engagement with the upper end of passageways  95  in bosses  94  formed as part of spacer  74 . Upon such assembly, case  151  with internally stacked PCBs will look like the representation illustrated in  FIGS. 14 and 15 . By inspection, it will be evident that third variant  150  contains four electrically and mechanically interconnected PCBs  62 ,  84 ,  114  and  154  within a case  151  conforming with the industry small form factor specification. As shown in  FIG. 14 , a label  100  may be placed on top of cover  92  for identification purposes.  
         [0044]     Referring to  FIG. 16 , there is shown a bottom view of second variant  110 . Reference numerals common to the second variant illustrated in  FIG. 10  will be used. The main purpose of  FIG. 16  is that of illustrating the electrical connectors on the bottom of each of the PCBs ( 84 ,  114 ). Electrical connector  180  extending from the bottom of PCB  84  mechanically and electrically interconnects with electrical connector  91  mounted on the top of PCB  62 . Similarly, electrical connector  182  on the bottom of PCB  84  mechanically and electrically interconnects with the other electrical connector  90  (see  FIG. 10 ) extending upwardly from PCB  62 . Electrical connector  184  extending downwardly from PCB  114  mechanically and electrically interconnects with electrical connector  113  on PCB  84  (see  FIG. 10 ). Similarly, electrical connector  186  extending downwardly from PCB  114  mechanically and electrically interconnects with the other electrical connector  112  on PCB  84  (see  FIG. 10 ). Thereby, the circuitry of PCB  62  is electrically connected with the circuitry of PCB  84  and the electrical circuitry of PCB  84  is electrically connected with the circuitry of PCB  114 .  FIG. 16  further illustrates the attachment of electrical connector  64  to the underside of PCB  62  as well as electrical connector  125  supporting pins  127  discussed above. It is to be understood that PCB  154  of third variant  150  ( FIG. 13 ) would include similar electrical connectors on the underside to electrically and mechanically mate with electrical connectors  152 ,  153  on PCB  114 .  
         [0045]     Thereby, in addition to electrical interconnection provided between the stacked PCBs, the PCBs are also mechanically mated with one another via the various electrical connectors. While  FIG. 16  primarily illustrates second variant  110 , it is to be understood that the electrical connectors interconnecting adjacent stacked PCBs would be used in each of the variants forming the cases for stackable PCBs discussed as well as in any further variants which embody the present invention.