Patent Publication Number: US-2007111550-A1

Title: Cable assembly

Description:
BACKGROUND  
      Electronic devices, such as servers and computers, often are installed in power distribution cabinets. A power distribution cabinet receives power from an external source, which power is provided to a backplane of the cabinet. The backplane of the cabinet provides power to the electronic devices housed in the cabinet via busbars and/or cables coupled therebetween. Busbars and cables are difficult to install and are expensive to repair. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      For a detailed description of exemplary embodiments of the invention, reference will now be made to the accompanying drawings in which:  
       FIG. 1  shows a three-dimension (3D) view of an illustrative power distribution cabinet (PDC), in accordance with embodiments of the invention;  
       FIG. 2   a  shows a 3D view of an illustrative cable assembly housed within a cable assembly sleeve, in accordance with embodiments of the invention;  
       FIG. 2   b  shows a plan view of the sleeve of  FIG. 2   a , in accordance with embodiments of the invention;  
       FIG. 3  shows a 3D view of a chassis used to protect and guide the cable assembly sleeve as the sleeve is coupled to a backplane of the cabinet, in accordance with embodiments of the invention;  
       FIG. 4  shows a 3D view of the installation of the cable assembly and sleeve in a PDC chassis, in accordance with embodiments of the invention;  
       FIG. 5  shows a 3D view of multiple cable assemblies and sleeves installed in the PDC chassis, in accordance with embodiments of the invention; and  
       FIGS. 6   a  and  6   b  show flow diagrams of processes used to install or repair an electronic device and/or a cable assembly in a PDC, in accordance with embodiments of the invention. 
    
    
     NOTATION AND NOMENCLATURE  
      Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, 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 or direct electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.  
     DETAILED DESCRIPTION  
      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.  
      Disclosed herein is a cable assembly sleeve capable of housing a cable that is used to electrically couple a power distribution cabinet (PDC) backplane to an electronic device housed within the PDC. The sleeve is made of a substantially rigid material and comprises additional features that facilitate the installation of cable assemblies and electronic devices in PDCs.  
       FIG. 1  shows a three-dimensional view of a PDC  100 . The PDC  100  comprises a power source  102 , a backplane  104  and an electronic device  108  which rests on one of a plurality of horizontal shelves  106 . In at least some embodiments, the electronic device  108  is a cell board, which is a logic board that may comprise components such as power converters, data buses, processors, memory, etc. In some such embodiments, multiple cell boards may be housed within a system, such as a server, as described further below. The PDC  100  comprises wheels  110  to facilitate movement of the PDC  100 , although the wheels  110  are not necessary. The power source comprises a power connection  118 , which in some embodiments comprises a plug that may be mated to an alternating current (AC) wall outlet. The power source  102  receives power via the power connection  118  and, in turn, provides AC or direct current (DC) power to the backplane  104  via a power connection  112 . The backplane  104  comprises a plurality of power connectors, such as the connector  116  shown in the figure. The connector  116  corresponds to a connector  114  on the electronic device  108 . By coupling the connector  116  to the connector  114 , the device  108  is powered. Thus, the transfer of power is as follows: a power source external to the cabinet  100  provides power to the power source  102  via the power connection  118 ; the power source  102  provides power to the backplane  104  via the power connection  112 ; and the backplane  104  provides power to the electronic device  108  via connector  116  which is coupled to connector  114 . Power provided by the backplane  104  is regulated by a power management processor  120  housed in the backplane  104 , as described further below.  
      In accordance with embodiments of the invention,  FIG. 2   a  shows a conductive cable assembly  200  that is used to electrically couple the connector  116  to the connector  114 , thus providing power from the backplane  104  to the electronic device  108 . The cable assembly  200  comprises a cable  201  that is housed in a rigid, hollow, partially insulative sleeve  202 . The sleeve may be made of a plastic material, such as polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene (ABS), or any of a variety of other plastics. At least some of the plastics that may be used to manufacture the sleeve  202  are provided in  Industrial Plastics , by Terry L. Richardson et al., Thomson Delmar Learning, September 2003, incorporated herein by reference. Alternatively, the sleeve  202  may be manufactured using non-plastics. The cable  201  may comprise any suitable conductive material, such as copper wiring, and an insulative material such as plastic around the conductive material. In some embodiments, the cable  201  may be incorporated into the sleeve  202  during a sleeve-molding process or, in other embodiments, the cable  201  may be incorporated into an already-formed sleeve  202 . Although the various embodiments disclosed herein are described in terms of a cable, at least some of these embodiments may substitute a rigid, metal (e.g., copper) bar in place of the cable.  
      Regardless of the material used to manufacture the sleeve  202 , in at least some embodiments, the material has an approximate resistivity of 10 8  Ohms/square unit (e.g., square inch, square centimeter). The scope of disclosure is not limited to using a material that is approximate to 10 8  Ohms/square unit. In general, the material used to manufacture the sleeve  202  is sufficiently insulative to prevent arcing between the cable assembly  200  and an adjacent cable assembly. However, the sleeve  202  also is sufficiently conductive to prevent an electrostatic discharge at the connector  114 , thus preventing damage to the connector  114  and/or the electronic device  108 . The shape of the sleeve  202  may be a cylinder with a circular, rectangular or elliptical cross section, although any shape may be used. The size (e.g., length, width, thickness) of the sleeve  202  is application-specific and may be adjusted as desired.  
      The sleeve  202  comprises connectors  204  and  210  on either end as shown. Each connector  204 ,  210  is coupled to the cable  201  housed inside the sleeve  202 , so that current flows between the connectors  204 ,  210  via the cable  201 . The connectors  204 ,  210  couple to the connectors  116 ,  114 , respectively. The connectors  204 ,  116  and the connectors  210 ,  114  can be any type of connectors, as long as the connectors  204 ,  116  and the connectors  210 ,  114  can be coupled to each other. For instance, the connector  204  may comprise a plurality of male pins which mate to a female connector  116 , or vice versa. Other types of connections may be used as desired.  
      The sleeve  202  optionally comprises multiple guide pins  206  that may be manufactured using the same material as the sleeve  202 . As shown in  FIG. 2   a , the guide pins  206  are located on the same end of the sleeve  202  as the connector  204 . In some embodiments, the guide pins  206  may comprise bullet-shaped (e.g., cylindrical) protrusions, although the scope of disclosure is not limited as such. The guide pins  206  are used to aid in guiding the connector  204  to “blind-mate” with the connector  116 , as described further below. The sleeve  202  also comprises a plate  212  that is coupled to the same end as the connector  210 . Captive screws  208 , as well as the connector  210 , may protrude through the plate  212 . The captive screws  208  protrude through the plate  212  on opposing sides of the connector  210 . The plate  212  and/or the screws  208  may be metal, plastic, or any other suitable type of material and of any suitable size and shape. For instance, as shown in  FIG. 2   a , the plate  212  may be of a substantially rectangular shape. The captive screws  208  and the plate  212  are used as described further below.  
       FIG. 2   b  shows a plan view of the cable assembly  200  as indicated by arrows  250  in  FIG. 2   a . In particular,  FIG. 2   b  shows the end of the assembly  200  that comprises the connector  204  and the guide pins  206 . The connector  204  is shown comprising multiple male connection pins  252 , although the scope of disclosure is not limited to using such pins to establish electrical connections between connectors. The connector  204  is fastened by the sleeve  202  such that the connector  204  is substantially immovable. That is, the connector  204  is tightly fastened by the sleeve  202  such that there is little or no “wiggle room” for the connector  204 . Such fastening of the connector  204  to the sleeve  202  aids in “blind-mating” the connector  204  to the connector  116 , as described further below. The guide pins  206  may be formed as part of the sleeve  202 , or the guide pins  206  may be formed separately from the sleeve  202  and subsequently attached to the sleeve  202 .  
       FIG. 3  shows a chassis  300  that is housed in the cabinet  100  (not shown in the cabinet  100  of  FIG. 1 ). More specifically, the chassis  300  is located between the electronic device  108  and the backplane  104 . The chassis  300  contains a frame comprising multiple I-beams  302  and multiple tunnels  304  formed between the I-beams  302  as shown. Each tunnel  304  is hollow and has an opening on each end of the tunnel. Each tunnel has one opening that is exposed to front-side plane  306  and another opening that is exposed to back-side plane  308 . Back-side plane  308  is substantially parallel to front-side plane  306 . As shown, the tunnels  304  are arranged substantially perpendicular to the I-beams  302 . The I-beams  302  serve to support the tunnels  304 . The I-beams  302  may be supported in the cabinet  100  by any suitable structure, such as the walls of the cabinet  100 . In at least some embodiments, the chassis  300  comprises a resistive material, such as PVC or ABS, although the scope of disclosure is not limited to these materials.  
       FIG. 4  shows the insertion of the cable assembly  200  into a tunnel  304   a  of the chassis  300 . The sleeve  202  is inserted into an opening of the tunnel  304   a  which is exposed on a front-side plane  306  of the chassis  300 . In at least some embodiments, the assembly  200  is inserted such that the connector  210  is exposed to the front-side plane  306  and the connector  204  is exposed to the back-side plane  308 . The tunnel  304   a  is of a size (e.g., length, width) such that the assembly  200  fits snugly into the tunnel  304   a  and such that the connectors  210 ,  204 , when the assembly  200  is fully inserted into the tunnel  304   a , are able to couple to connectors  114 ,  116 , respectively, as described below. Although not specifically shown, additional cable assemblies may be inserted into the other tunnels  304  in the chassis  300  to provide power from the backplane  104  to additional electronic devices in the cabinet  100 .  
       FIG. 5  shows the chassis  300  installed in the cabinet  100 . Each tunnel  304  in the chassis  300  houses a cable assembly. For illustrative purposes, tunnel  304   a  is shown with portions of the tunnel  304   a  and portions of the sleeve  202  removed. As can be seen, the tunnel  304   a  comprises the cable  201  housed within the sleeve  202 . The connector  204  and the guide pins  206  protrude from the tunnel  304   a  at the back-side plane  308  when the plate  212  abuts the tunnel  304   a.    
      The chassis  300  is installed in the cabinet  100  at a distance from the backplane  104  such that, when the assembly  200  is fully inserted in the tunnel  304   a , the connector  204  snugly couples with the connector  116  on the backplane  104 . In some embodiments, the optional guide pins  206  mate with holes (not specifically shown) on opposing sides of the connector  116  on the backplane  104 . When the chassis  300  is installed in the PDC  100 , an assembly  200  can be inserted into a tunnel (e.g., tunnel  304   a ), causing the connector  204  on sleeve  202  to electrically couple with the corresponding connector  116  on the backplane facilitated, if desired, by the guide pins  206  mating with corresponding holes. Just as the assembly  200  has a connector  204  that mates with the connector  116 , the assemblies inserted into the other tunnels  304  also have connectors (and optionally, guide pins) that couple to the backplane  104  via connectors on the backplane  104 .  
       FIG. 6   a  shows a process  600  that may be used to install an electronic device  108  in the cabinet  100 . The process begins by inserting assembly  200  into a tunnel  304  (block  602 ) and blind mating the connector  204  with the connector  116  (block  604 ). The term “blind mating” implies that due to the rigidity of the sleeve  202 , the connector  204  may be readily mated to the connector  116 , regardless of whether the connectors  204 ,  116  are visible to a user coupling the connectors  204 ,  116 . More specifically, the sleeve  202  facilitates the blind mating of the connectors  204 ,  116  because the sleeve  202  is rigid, unlike, in at least some embodiments, the cable  201 . Because the sleeve  202  is rigid, the cable  201  (housed in the sleeve  202 ) can quickly be inserted through the tunnel  304   a  and coupled to the backplane  104 . The guide pins  206  may also be used to ensure that the connectors  204 ,  116  are being properly blind-mated and to avoid any damage to the connectors  204 ,  116 .  
      Without the sleeve  202 , coupling the connector  204  to the connector  116  would be difficult, since the cabinet  100  may be crowded with wires and other electronic devices, and further because the chassis  300  minimizes or eliminates hand-maneuvering space. Because the sleeve  202  facilitates coupling together the connectors  204 ,  116 , the amount of time it takes to install the cable assembly  200  is substantially shorter than the time it would take to install the cable  201  without the sleeve  200 .  
      The process  600  further comprises using screws  208  to fasten the plate  212  to the chassis  300  (block  606 ), effectively fastening the cable assembly  200  to the chassis  300  to keep the assembly  200  from slipping out of place. The process  600  then comprises installing the electronic device  108  (e.g., in a server) if not already installed, and coupling connector  114  to the connector  210  (block  608 ), thereby establishing an electrical connection between the device  108  and the backplane  104 .  
      In at least some embodiments, multiple electronic devices  108  may be housed together within a single system, such as a server (not specifically shown). For example, a server may house multiple (e.g., four) electronic devices  108  (e.g., cell boards), each device  108  receiving power from the backplane  104  via its own cable assembly  200 . In some such embodiments, the electronic devices  108  housed in the server are hot-swappable, meaning that if one of the devices  108  fails, then that failed device  108  can be removed and fixed or replaced without having to power down the server and thus the other devices  108  contained therein. Similarly, an individual cable assembly  200  can be removed and replaced without having to power down all of the devices  108  within the server—only the device  108  connected to the removed cable assembly  108  would be powered down.  
      More specifically, in case either a device  108  (e.g., housed in a server) and/or a corresponding cable assembly  200  fails, the management processor  120  may detect the failure and may, in some instances, cut off power supply to the defective device  108  and the assembly  200 . In some embodiments, the processor  120  also may cause a display (not shown) coupled to the cabinet and/or the server to display an alert message to a user, warning the user of the failure. In turn, the user may address the failure using a process  650  as shown in  FIG. 6   b.    
      The process  650  comprises disconnecting the connectors  210 ,  114  without powering down the server (block  652 ). By disconnecting the connectors  210 ,  114 , the device  108  is powered down, but the server otherwise continues to function. Thus, the device  108  is “hot-swappable.” In case it is the device  108  that has failed (block  654 ), the process  650  comprises repairing or replacing the device  108  (block  656 ), inserting the repaired or replaced device  108  into the server (block  658 ), and coupling the connectors  210 ,  114  to power up the device  108  (block  660 ). However, in case the cable assembly  200  is defective (block  654 ), the process  650  comprises unscrewing the screws  208  (block  662 ) and pulling out the cable assembly  200  from the tunnel  304   a  (block  664 ). The process  650  then comprises repairing or replacing the cable assembly  200  (block  666 ) and inserting the repaired or replaced cable assembly  200  into tunnel  304   a  (block  668 ). The process  650  further comprises inserting the cable assembly  200  into the tunnel  304   a , blind-mating the assembly  200  to the backplane  104  (block  670 ) using connectors  204 ,  116  and the guide pins  206 , and fastening the assembly  200  to the chassis  300  using the screws  208  (block  672 ). Finally, the connector  114  of the device  108  is mated to the connector  210  of the cable assembly  200  (block  674 ), thus powering the device  108 .  
      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, although the embodiments are described above as being used to transfer power, they also may be used to transfer electrical data signals. It is intended that the following claims be interpreted to embrace all such variations and modifications.