Abstract:
A method and apparatus are provided for implementing simultaneously connecting of multiple devices in a multi-tiered, multi-directional, enhanced tolerance system with mechanical support structures. A main system planar assembly and an elevated planar assembly share a direct connection provided by a plurality of connectors with no cables. A mechanical support bracket is attached to a top surface of the main system planar assembly positioning and supporting the elevated planar assembly spaced appropriately for accurately connecting respective connectors with respective chassis connectors. The elevated planar assembly includes a stiffening component to facilitate proper spacing between upper and lower levels of respective connectors and tool-less insertion and extraction of the elevated planar assembly.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to the data processing field, and more particularly, relates to method and apparatus for implementing simultaneously connecting of multiple devices in a multi-tiered, multi-directional, enhanced tolerance system with mechanical support structures. 
       DESCRIPTION OF THE RELATED ART 
       [0002]    There are cases where a system, such as a single server product is designed to plug and fill the space of two adjacent slots on its respective host chassis mid-plane. In this scenario, the need can arise for multiple circuit boards to be arranged in a stacked fashion to support the connectors that dock to the chassis mid-plane. Additionally, the stacked circuit boards must share a connection with each other. 
         [0003]    To accomplish the task of reliable docking and undocking, the method of stacking multiple levels of circuit boards within the server product must satisfy rigidity requirements and obey the critical mechanical tolerance values set forth by connector arrangements on the chassis mid-plane. 
         [0004]    One way to successfully stack circuit boards is to isolate the mechanical structures that support each individual board. In doing so, a flexible cable could be designed to bridge the connection from one circuit board to the next. The utilization of a cable, however, adds significant expense to the system as well as increasing the need for extra parts to be procured and stocked. 
         [0005]    These extra parts also add steps when assembling and disassembling the circuit boards to and from one another within the server node. As such, appreciable cost and complication are increased when implementing this type of solution including one or more cables. 
         [0006]    Another potential solution would be to assemble the stacked circuit boards such that they are allowed to float with respect to one another. While this might allow the chassis mid-plane connector pairs to dock appropriately, the stacked circuit board connection is not compliant enough to expand and collapse in order to allow the circuit boards to float. As identified during product development studies, pin wipe and tolerance requirements when dealing with a direct board-to-board stacked connection can force a floating mechanical solution out of the realm of feasibility. 
         [0007]    A need exists for an efficient and effective method and apparatus for simultaneously connecting of multiple devices in a multi-tiered, multi-directional, enhanced tolerance system with mechanical support structures. 
       SUMMARY OF THE INVENTION 
       [0008]    Principal aspects of the present invention are to provide a method and apparatus for implementing simultaneously connecting of multiple devices in a multi-tiered, multi-directional, enhanced tolerance system with mechanical support structures. Other important aspects of the present invention are to provide such method and apparatus substantially without negative effects and that overcome many of the disadvantages of prior art arrangements. 
         [0009]    In brief, a method and apparatus are provided for implementing simultaneously connecting of multiple devices in a multi-tiered, multi-directional, enhanced tolerance system. A main system planar assembly and an elevated planar assembly share a direct connection provided by a plurality of respective connectors. A mechanical support bracket is attached to a top surface of the main system planar assembly positioning and supporting the elevated planar assembly spaced appropriately for accurately connecting respective connectors with respective chassis connectors. The elevated planar assembly includes a stiffening component to facilitate proper spacing between upper and lower levels of respective connectors and tool-less insertion and extraction of the elevated planar assembly. 
         [0010]    In accordance with features of the invention, the plurality of respective connectors for accurate connecting with respective chassis connectors are provided for connecting with respective chassis connectors without requiring cables. 
         [0011]    In accordance with features of the invention, the mechanical support bracket includes predefined positioning features cooperating with predefined features of the main system planar assembly positioning and retaining the elevated planar assembly. 
         [0012]    In accordance with features of the invention, the mechanical support bracket and stiffening component are provided in direct contact engagement. 
         [0013]    In accordance with features of the invention, the mechanical support bracket and stiffening component respectively are formed by injection molding technique and each formed of a selected electrically non-conducting material having sufficient strength and rigidity providing predefined mechanical support for positioning and retaining the elevated planar assembly. 
         [0014]    In accordance with features of the invention, an interposer assembly is assembled with the mechanical support bracket. 
         [0015]    In accordance with features of the invention, a pair of latching arms are attached to the stiffening component of the elevated planar assembly and allow for easy, tool-less installation and extraction of the elevated planar assembly to and from the system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The present invention together with the above and other objects and advantages may best be understood from the following detailed description of the preferred embodiments of the invention illustrated in the drawings, wherein: 
           [0017]      FIG. 1  is a perspective view not to scale of a main system planar assembly in accordance with a preferred embodiment; 
           [0018]      FIG. 2  is a perspective view not to scale of a mechanical support bracket in accordance with a preferred embodiment; 
           [0019]      FIG. 3  is a perspective view not to scale of the mechanical support bracket of  FIG. 2  attached to a top surface of the main system planar of  FIG. 1  in accordance with a preferred embodiment; 
           [0020]      FIG. 4  is a perspective view not to scale of an interposer assembly in accordance with the preferred embodiment; 
           [0021]      FIG. 5  is a perspective view not to scale of the interposer assembly of  FIG. 4  assembled with the mechanical support bracket of  FIGS. 2 and 3  in accordance with the preferred embodiment; 
           [0022]      FIG. 6  is a perspective view not to scale of an elevated planar circuit board assembly in accordance with the preferred embodiment; 
           [0023]      FIG. 7  is a bottom plan view not to scale of the elevated planar circuit board assembly of  FIG. 6  in accordance with the preferred embodiment; and 
           [0024]      FIG. 8  is a perspective view not to scale of the elevated planar circuit board assembly of  FIGS. 6 and 7  assembled into a final system assembly together with the mechanical support bracket of  FIGS. 2 and 3  including the interposer assembly of  FIGS. 4 and 5 , the elevated planar circuit board assembly including the stiffener component of  FIGS. 6 and 7  and the main system planar assembly of  FIG. 1  in accordance with the preferred embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    In the following detailed description of embodiments of the invention, reference is made to the accompanying drawings, which illustrate example embodiments by which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention. 
         [0026]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
         [0027]    In accordance with features of the invention, a method and apparatus are provided for implementing simultaneously connecting of multiple devices in a multi-tiered, multi-directional, enhanced tolerance system. 
         [0028]    Having reference now to the drawings, in  FIG. 1 , there is shown a main system planar assembly generally designated by the reference character  100  in accordance with a preferred embodiment. The main system planar assembly  100  includes a plurality of respective connectors, each connector generally designated by the reference character  102 . The illustrated connectors  102  are mounted on a top surface  104  of a main system planar circuit board assembly generally designated by the reference character  106 . The main system planar circuit board assembly  106  is loaded into a sheet metal chassis pan  108 . The main system planar circuit board assembly  106  includes predefined positioning features  112 ,  114  cooperating with predefined features of a mechanical support bracket  200  illustrated with respect to  FIG. 2 . 
         [0029]    Referring to  FIG. 2 , a mechanical support bracket generally designated by the reference character  200  is shown in accordance with a preferred embodiment. 
         [0030]    Referring also to  FIG. 3 , there is shown an assembly generally designated by the reference character  300  of the mechanical support bracket  200  attached to a top surface  104  of the main system planar assembly  100  in accordance with a preferred embodiment. 
         [0031]    The mechanical support bracket  200  is an integral unit or unitary memory  200 , for example, formed by injection molding technique and formed of a selected electrically non-conducting material having sufficient strength and rigidity providing predefined mechanical support for positioning and retaining an elevated planar assembly  600  illustrated and described with respect to  FIGS. 6 and 7 . 
         [0032]    The mechanical support bracket  200  includes predefined positioning features  210 ,  212  defining respective cooperating cavities with the predefined features  112 ,  114  of main system planar circuit board assembly  106  for positioning and retaining the elevated planar assembly of  FIGS. 6 and 7 . The predefined positioning features  210 ,  212  are shown surrounding the predefined features  112 ,  114  of main system planar circuit board assembly  106  in  FIG. 3 . 
         [0033]    The mechanical support bracket  200  includes a pair of support columns  214  mounted with the main system planar assembly  106 , and an upper end  216  for mounting with an interposer card illustrated and described with respect to  FIGS. 4 and 5 . The mechanical support bracket  200  includes a plurality of contact support ledges or support points  220  for mounting with the elevated planar assembly of  FIGS. 6 and 7 . 
         [0034]    Referring to  FIG. 4 , there is shown an interposer assembly generally designated by the reference character  400  in accordance with the preferred embodiment. The interposer assembly  400  is secured to the mechanical support bracket  200  as shown in an assembly  500  of  FIG. 5 . The interposer assembly  400  includes an interposer card designated by the reference character  402 , an upper member  404  and a lower member  406 . The interposer card  402  includes notches  408  respectively receiving and retaining fasteners provided within the upper ends  216  of support columns  214  of the mechanical support bracket  200  shown in  FIG. 2 . For example, the interposer card  402  is used to support a predefined stacked connector group. The interposer assembly  400  includes a connector  606  as illustrated in an elevated planar circuit board assembly  600 . 
         [0035]    Referring to  FIG. 5 , there is shown an assembly generally designated by the reference character  500  of the interposer assembly  400  assembled with the mechanical support bracket  200  in accordance with the preferred embodiment. A pair of fasteners  502  is provided within notches  408  securing the interposer card  402  with the mechanical support bracket  200 . The mechanical support bracket  200  sets the appropriate height for mating a lower connector pair in the stack between the top surface  104  of the main system planar circuit board assembly  106  to a bottom surface of the interposer card  402 . 
         [0036]    Referring to  FIG. 6 , there is shown an elevated planar circuit board assembly generally designated by the reference character  600  in accordance with the preferred embodiment. The illustrated elevated planar circuit board assembly  600  includes a pair of latching arms  602  that are shown in a partially open position. The latching arms  602  are attached to a stiffener  604  and allow for easy, tool-less installation and extraction of the elevated planar assembly  600  to and from the final system assembly  800  illustrated and described with respect to  FIG. 8 . A final stacked connector  606  resides on a bottom side  608  of an elevated planar circuit board  610 , while an upper chassis mid-plane connector  102  and the stiffener  604  reside on a top surface  612  of the board  610 . 
         [0037]    Referring to  FIG. 7 , there is shown a bottom plan view not to scale of the elevated planar circuit board assembly  600  with the interposer assembly  400  in accordance with the preferred embodiment. As visible in  FIG. 7 , portions of the circuit board  610  have been removed to expose corners  704  of the elevated planar assembly  600 . The four locations  702  indicated by arrows  702  come into direct contact with the support bracket  200  shown in  FIG. 2  when the elevated planar assembly  600  is fully incorporated into the final system assembly  800 . The stiffener  604  optionally is stabilized by additional structures (not shown) within the system  800  or server product. Such added support can be provided if needed to prevent excessive rocking of the elevated planar assembly  600 , for example, when daughter cards are plugged and unplugged within the upper tier of the system assembly  800 . 
         [0038]    Referring to  FIG. 8 , there is shown a final system assembly generally designated by the reference character  800  in accordance with the preferred embodiment. The final system assembly  800  includes the elevated planar circuit board assembly  600  assembled into the system  800  with the main system planar assembly  100  assembled with the mechanical support bracket  200  including the interposer assembly  400 , with the elevated planar circuit board assembly  600  including the stiffener component  604 . Two of four locations  802  are indicated by arrows show where the topside stiffener  604  of the elevated planar assembly  600  comes into direct contact with the shoulders or ledges  220  of the mechanical support bracket  200 , with the additional contact points at the opposite side of the elevated planar circuit board assembly  600 . 
         [0039]    The latching arms  602  are pre-loaded upwardly against the mechanical support bracket  200 , which provides for rigid and secure engagement. Dimensionally, one key aspect is that the respective top surfaces  104 ,  612  of both the main system planar circuit board assembly  106  and elevated planar circuit board  610  are spaced appropriately for accurate connector docking to the chassis mid-plane. The reason for this accurate connector docking is that the seated contact made between the mechanical support bracket  200  and topside stiffener  604 , both of which are affixed to the top surface  104 ,  612  of their respective circuit boards. Consequently, several tolerances including board thickness, board flatness, connector stack height, and attach co-planar tolerances, are eliminated from the vertical spacing of the upper and lower sets of chassis mid-plane connectors. Instead, these tolerance values for both the elevated planar board  610  and interposer board  402  are transferred to the pin wipe allowance of the upper stacked connector pair including interposer upper member  404  and connector  606 . This pair must not be over or under-docked, which is achievable in the illustrated arrangement of the final assembly system  800 . 
         [0040]    In brief summary, the mechanical support bracket  200  and topside stiffener component  604 , and their associated interaction, are arranged such that the upper and lower connector pairs are not fully docked. This effectively eliminates the tolerances of interposer  400 , and elevated planar assembly  600  from the stack-up and therefore minimizes the overall tolerances in the system  800  such that both main planar assembly  100  and elevated planar assembly  600  can plug into the chassis mid-plane connectors without issue. Also, the mechanical support bracket  200  and topside stiffener  604  are sufficiently rigid so that the underdocked upper and lower connector pairs are immobilized to prevent connector pin and contact micro-motion that could come from external vibration forces. 
         [0041]    While the present invention has been described with reference to the details of the embodiments of the invention shown in the drawing, these details are not intended to limit the scope of the invention as claimed in the appended claims.