Abstract:
System and method for positioning a midplane within a computer chassis. In some embodiments, a computer system includes a chassis, a midplane disposed within the chassis, and a plunger pin coupled to the midplane. The plunger pin is selectably movable between a first position, wherein the midplane is immovable relative to the chassis, and a second position, wherein the midplane is moveable relative to the chassis.

Description:
BACKGROUND 
       [0001]    Some servers have an outer chassis and a midplane board (or simply a “midplane”) supported therein. Processor cards and input/output (I/O) cards are connected to and extend from both sides of the midplane within the chassis. Typically these servers also include other components, such as power supply units and cooling fans, coupled to either or both sides of the midplane. 
         [0002]    Precise positioning and fixturing of the midplane within the chassis enables reliable coupling of components to both sides of the midplane. Once so connected, minimized movement of the midplane promotes continued engagement of the components with the midplane. In the event that repair of the midplane becomes necessary, removal of the midplane from the chassis, servicing, and replacement may be required. During these operations, the server is unavailable. Moreover, servicing of the server and access to the midplane can be cumbersome. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    For a detailed description of exemplary embodiments of the invention, reference will now be made to the accompanying drawings in which: 
           [0004]      FIGS. 1A and 1B  show perspective front and rear views, respectively, of a computer in accordance with the invention; 
           [0005]      FIGS. 2A and 2B  show perspective front and rear views, respectively, of the computer of  FIG. 1  with the sides of the chassis removed, exposing to view the blades, midplane, and I/O chassis; 
           [0006]      FIGS. 3A and 3B  show perspective rear and enlarged rear views, respectively, of the midplane of the computer of  FIG. 1 ; 
           [0007]      FIGS. 4A and 4B  are cross-sectional views of one plunger pin in its retracted and extended positions, respectively; 
           [0008]      FIGS. 5A through 5C  are perspective, enlarged exterior, and enlarged interior views, respectively, of the computer chassis; 
           [0009]      FIGS. 6A and 6B  are perspective and enlarged interior views, respectively, of the computer chassis, illustrating engagement of the midplane with the chassis; and 
           [0010]      FIG. 7  is a flowchart illustrating an exemplary method for positioning the midplane within the computer chassis in accordance with the invention. 
       
    
    
     NOTATION AND NOMENCLATURE 
       [0011]    Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, computer companies may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . . ” Also, the term “couple” or “couples” is intended to mean either an indirect, direct, optical or wireless electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, through an indirect electrical connection via other devices and connections, through an optical electrical connection, or through a wireless electrical connection. 
       DETAILED DESCRIPTION 
       [0012]    The following discussion is directed to various embodiments of the invention. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment. 
         [0013]      FIGS. 1A and 1B  show perspective front and rear views, respectively, of a computer, such as but not limited to a server, in accordance with the invention. C  100  has a chassis or housing  105 . In this embodiment, computer chassis  105  is a generally rectangular structure with four sides  110  bounding an interior chamber  115  ( FIG. 5A ), in which other components of computer  100 , generally designated  120 , are disposed. Computer chassis  105  further includes an open-ended front  125  and an open-ended rear  130 , both enabling access to interior chamber  115  and components  120  disposed therein. 
         [0014]    Turning to  FIGS. 2A and 2B , computer  100  is shown with sides  110  of chassis  105  removed, thereby exposing the other computer components  120  to view. As shown, computer  100  further includes an I/O chassis  135 , a midplane board (“midplane”)  140 , and a plurality of components coupled to midplane  140  and generally designated  145 . In this embodiment, components  145  coupled to midplane  140  include a digital versatile disc (DVD) assembly  150 , a plurality of blades  155 , bulk power supply (BPS) units  160 , fan assemblies  165 , and switches or I/O cards  170 . 
         [0015]    Midplane  140  extends substantially normal to a longitudinal centerline  175  of computer chassis  105  and is releasably coupled thereto, as will be described. Midplane  140  enables communication between blades  155  and I/O cards  170  coupled thereto and distribution of power from BPS units  160  to blades  155 , I/O cards  170 , DVD assembly  150 , and fan assemblies  165 . Midplane  140  has a front side  180  and a back side  185  with a plurality of connectors  190  (visible in  FIG. 3A ) coupled to and extending from each. Connectors  190  enable coupling of components  145  to midplane  140 . 
         [0016]    Each of blades  155  extends substantially parallel to computer chassis axis  175  from front side  180  of midplane  140  to front  125  of chassis  105 . In some embodiments, each blade  150  includes a motherboard having one or more central processing units (CPUs) and memory for data storage. In this embodiment, computer  100  includes eight blades  155 . 
         [0017]    I/O chassis  135  is disposed adjacent back side  185  of midplane  140  and extends between midplane  140  and rear  130  of computer chassis  105 . I/O chassis  135  receives and supports fan assemblies  165  and I/O cards  170 , enabling the coupling of these components  165 ,  170  to midplane  140 . As one of ordinary skill in the art readily appreciates, fan assemblies  165  provide cooling to blades  155 , DVD assembly  150 , BPS units  160 , and I/O cards  170 . I/O chassis  135  includes two handles  195  that enable installation of I/O chassis  135  into computer chassis  105  and removal of I/O chassis  135  from computer chassis  105 . 
         [0018]    Because the various components  145  described above couple to both sides  180 ,  185  of midplane  140 , precise positioning of midplane  140  within computer chassis  105  is required. To facilitate precise positioning of midplane  140  within computer chassis  105 , midplane  140  further includes a plurality of plunger pins  200 , best viewed in  FIGS. 3A and 3B . As will be described, plunger pins  200  are manually actuatable to interlock midplane  140  within computer chassis  105 . 
         [0019]      FIGS. 3A and 3B  depict perspective rear and enlarged rear views, respectively, of midplane  140 . Referring first to  FIG. 3A , the exemplary embodiment of midplane  140  has a longitudinal centerline  205  and a housing  210  disposed about its back side  185 . When midplane  140  is installed within computer chassis  105 , as illustrated by  FIGS. 1A and 1B , midplane centerline  205  and computer chassis centerline  175  are coincident. Referring still to  FIG. 3A , housing  210  is substantially rectangular in shape and thus has four corners  215 . At each corner  215 , midplane housing  210  has a flanged portion or extension  220 . Midplane  140  further includes a plunger pin  200  coupled to flanged portion  220  and an internal embossment  225  disposed on back side  185  of midplane  140  proximate the plunger pin  200 . 
         [0020]    As best viewed in  FIG. 3B , flanged portion  220  extends from midplane housing  210  substantially parallel to midplane centerline  205  ( FIG. 3A ). Flanged portion  220  has an interior surface  230 , an exterior surface  235 , and a throughbore  240  extending therebetween. Plunger pin  200  is coupled within throughbore  240  to flanged portion  220 . 
         [0021]    In some embodiments, plunger pin  200  has an outer housing  245 , a pin member  250  extending therethrough, and a central axis  255 . Pin housing  245  enables coupling of plunger pin  200  to flanged portion  220  of midplane housing  210 . In some embodiments, an end of pin housing  245  is received within throughbore  240  of flanged portion  220  of midplane housing  210 . Central axis  255  of plunger pin  200  is substantially normal to midplane centerline  205  ( FIG. 3A ) and is thus normal to computer chassis centerline  175  when midplane  140  is installed within computer chassis  105 . 
         [0022]    Turning to  FIGS. 4A and 4B , pin member  250  has an elongate body  265  extending between an inner end  270  with a flanged head  275  and an outer end  280 . Pin member  250  is translatable relative to pin housing  245  along central axis  255  between a retracted position, illustrated by  FIG. 4A , and an extended position, illustrated by  FIG. 4B . In the extended position ( FIG. 4B ), end  280  of pin member  250  extends beyond exterior surface  235  of flanged portion  220 . In the retracted position ( FIG. 4A ), the opposite is true, meaning end  280  does not extend beyond exterior surface  235 . 
         [0023]    In some embodiments, plunger pin  200  is spring-loaded, having a spring  285  disposed within pin housing  245  about pin member  250 . Further, in some such embodiments, pin member  250  is biased by spring  285  to its extended position ( FIG. 4B ). Hence, in the absence of a tension load, pin member  250  assumes its extended position. When a tension load is applied to head  275  of pin member  250  in excess of the biasing force of spring  285 , pin member  250  is displaced toward its retracted position ( FIG. 4A ). Once retracted, removal of the applied tension load allows pin member  250  to return to its extended position ( FIG. 4B ) under force from spring  285 . Thus, application and removal of tension to head  275  enables translation of pin member  250  between its retracted and extended positions, respectively. 
         [0024]    Still further, in some embodiments, pin member  250  is operable to lock in its retracted position ( FIG. 4A ) such that when an applied tension load is removed, pin member  250  is prevented from returning to its extended position. In such embodiments, pin member  250  is also rotatable relative to pin housing  245  about central axis  255 . As before, when a tension load is applied to head  275  of pin member  250  exceeding the biasing spring force, pin member  250  is displaced to its retracted position ( FIG. 4A ). Once in the retracted position, pin member  250  is then rotated relative to pin housing  245  into a locked position. When in the locked position, pin member  250  is constrained from translating relative to pin housing  245  in a direction toward flanged portion  220  of midplane housing  210 , even when the applied tension load is removed. 
         [0025]    To return pin member  250  to its extended position ( FIG. 4B ) from a locked, retracted position, pin member  250  is again rotated relative to pin housing  245  but in the opposite direction from the locked position to an unlocked position. Once in the unlocked position, pin member  250  is free to translate relative to pin housing  245  when the applied tension load is removed. Thus, in this manner, pin member  250  is translatable between extended and retracted positions and rotatable between unlocked and locked positions. 
         [0026]    Referring again to  FIG. 3B , internal embossment  225  protects plunger pin  200 . Internal embossment  225  is a protrusion coupled to, or formed in, back side  185  of midplane  140 . At least a portion of internal embossment  225  is laterally aligned with head  275  of plunger pin  200 , wherein the lateral direction  290  ( FIG. 3A ) is normal to midplane centerline  205 . Internal embossment  225  extends from back side  185  toward plunger pin  200 , leaving some clearance  295  (see also  FIG. 4A ) between embossment  225  and plunger pin  200 . In the event that a load is applied to pin member  250 , for example, due to inadvertent contact with other computer components  145  during assembly, head  275  of pin member  250  will displace and engage internal embossment  225 . Internal embossment  225  subsequently supports pin member  250  in resisting the applied load and prevents pin member  250  from breaking. Clearance  295  is selected such that embossment  225  does not interfere with actuation of plunger pin  200 , and pin member  250 , when inadvertently contacted, displaces to engage and be supported by embossment  225  prior to breaking. 
         [0027]    Turning now to  FIGS. 5A through 5C , computer chassis  105  further includes a plurality of cutouts  300  and a plurality of stop pins  305 . In this embodiment, there are an equal number of cutouts  300  and plunger pins  200 . Each cutout  300  extends from between an interior surface  310  and an exterior surface  315  of computer chassis  105  and is shaped to receive end  280  of one plunger pin  200 . Each stop pin  305  extends substantially normally from interior surface  310  of computer chassis  105  and has a length sufficient to engage midplane  140  when midplane  140  inserted into chassis  105 . 
         [0028]    The positioning and number of cutouts  300  and stop pins  305  are such that when midplane  140  is inserted within chassis  105 , front side  180  of midplane  140  abuts stop pins  305  when plunger pins  200  align with cutouts  300  in chassis  105 , as illustrated by  FIGS. 6A and 6B . Stop pins  305  prevent further insertion of midplane  140  into chassis  105 . With plunger pins  200  aligned with cutouts  300 , pin members  250  of plunger pins  200  are then manually actuated to displace pin members  250  to their extended positions, thereby causing end  280  of each pin member  250  to be received within an aligned cutout  300 . When ends  280  of pin members  250  are received within cutouts  300 , midplane  140  is interlocked within computer chassis  105  and immovable relative to computer chassis  105 . 
         [0029]    As used herein, the term “immovable” means midplane  140  does not move relative to chassis  105  but for small relative displacement resulting from clearance between the inner surface of chassis  105  defining each cutout  300  and the outer surface of pin member  250  inserted therein. Such clearances are a function of the tolerances of cutout and pin member dimensions and enable pin members  250  to be received within cutouts  300 . But for the small relative movement or “play” permitted by these clearances, midplane  140  does not move relative to chassis  105  when interlocked via plunger pins  200  and cutouts  300 . Furthermore, in some embodiments, midplane  140  does not move at all relative to chassis  105  once interlocked with chassis  105 . 
         [0030]    Referring again to  FIGS. 5A and 5B , computer chassis  105  further includes an external embossment  325  extending from exterior surface  315  of chassis  105  proximate each cutout  300 . External embossments  325  protect plunger pins  200  when midplane  140  is interlocked with computer chassis  105 . Each external embossment  325  is axially aligned, defined relative to computer centerline  175  ( FIG. 1A ), with the proximal cutout  300 , and has an axial length  330  and a height  335  defined relative to exterior surface  315  of computer chassis  105 . The axial length  330  of each external embossment  325  exceeds the axial width  340  of the proximal cutout  300 . 
         [0031]    As previously described and illustrated by  FIG. 6B , ends  280  of pin members  250  of plunger pins  200  extend through cutouts  300  of computer chassis  105  when midplane  140  is interlocked within computer chassis  105 . Height  335  of each external embossment  325  is selected such that it exceeds the length of the portion of pin member  250  that extends from cutout  300  when midplane  140  is interlocked within computer chassis  105 . Thus, external embossment  325  bears the brunt of inadvertent loads to computer  100  in this region rather than pin member  250  extending from cutout  300 . 
         [0032]    Turning finally to  FIG. 7 , a flowchart is depicted illustrating an exemplary method  700  for positioning midplane  140  within computer chassis  105 . As illustrated, plunger pins  200  are actuated by application of a tension load to each pin member  250 , thereby causing pin members  250  to translate relative to outer housings  245  to their retracted positions ( FIG. 4A ). (Block  705 ) In embodiments wherein plunger pins  200  are spring-loaded and pin members  250  are biased toward their extended positions ( FIG. 4B ) by springs  285 , translation of pin members  250  toward their retracted positions compresses springs  285 . Further, in embodiments wherein pin members  250  may be locked in their retracted positions, pin members  250  are then rotated relative to outer housings  245 , thereby locking pin members  250  in their retracted positions and preventing them from translating relative to outer housings  245  when the applied tension loads are removed. (Block  710 ). 
         [0033]    Next, midplane  140  is aligned with an open end of computer chassis  105  (block  715 ) and then inserted into chassis  105  until abutting stop pins  305  (block  720 ). When midplane  140  abuts stop pins  305 , midplane  140  is positioned in the desired location relative to chassis  105 , such that components  145  may be subsequently coupled to midplane  140 , and plunger pins  200  are aligned with cutouts  300  in computer chassis  105 . 
         [0034]    To interlock midplane  140  within chassis  105 , pin members  250  are rotated in a direction opposite that described above with reference to block  710  to unlock pin members  250 , if applicable. (Block  725 ) After pin members  250  are unlocked and tension loads applied to pin members  250  are removed, springs  285  within plunger pins  200  expand to translate pin members  250  from their retracted positions to their extended positions (block  730 ) with ends  280  of pin members  250  received within cutouts  300  of chassis  105  (block  735 ). When ends  280  of pin members  250  are received within cutouts  300  of chassis  105 , midplane  140  is interlocked within chassis  105  and prevented from movement relative to chassis  105 . 
         [0035]    The method of positioning midplane  140  within computer chassis  105  described above and illustrated by  FIG. 7  is but one example for interlocking midplane  140  within chassis  105  in accordance with the invention. In other embodiments, at least some of the steps described above and shown in  FIG. 7  may be performed in a different order. For example, midplane  140  may be aligned with an open end of computer chassis  105  and pin members  250  retracted subsequent to such alignment. 
         [0036]    Appropriate positioning of cutouts  300 , stop pins  305 , and plunger pins  200  enables precise positioning of midplane  140  within computer chassis  105 . After components  145  are disposed within computer chassis  105  and coupled to midplane  140 , plunger pins  200  engaged with computer chassis  105  prevent midplane  140  from moving and inadvertently decoupling from one or more components  145 . Furthermore, because plunger pins  200  are manually actuated to extend to engage computer chassis  105  during assembly and to retract to disengage chassis  105  during disassembly, servicing of midplane  140  is facilitated, enabling less downtime of computer  100  for repair and/or replacement of midplane  140  when needed. 
         [0037]    The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. For example, the number and positioning of plunger pins, stop pins, and cutouts may vary. It is intended that the following claims be interpreted to embrace all such variations and modifications.