Abstract:
A rail assembly having a stab-in inner rail member that inserts into and withdraws from an intermediate rail member supports an information handling system chassis disposed in a rack. Insertion of the inner rail member into the intermediate rail member is aided by a resting surface extending from the insertion end of the intermediate rail member. The inner rail member rests on and is aligned with the resting surface so that opposing pairs of rail assemblies can have their inner rail members aligned with their intermediate rail members during a stab-in assembly of a chassis into the rack.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to the field of information handling system rack mounting rails, and more particularly to an information handling system slide rail alignment support. 
     2. Description of the Related Art 
     As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems. 
     Server information handling systems and other data center equipment are typically mounted in racks using telescoping slide rails. One rack often holds numerous information handling systems stacked vertically in order to maintain the systems in a safe and secure environment. Power and cooling resources are generally applied through the rack structure so that the information handling systems in the rack are enclosed in the rack structure unless maintenance or replacement of a particular chassis is required. When access is needed to a particular chassis, the chassis is slid from the rack with the telescoping slide rails. Often, the chassis is completely removed so that internal components are readily accessible or so that a replacement chassis can be inserted in its place. To provide ready access to a chassis in a rack, one common method for mounting the chassis in the rack is the “stab-in” method, which involves removing inner members from the rail assemblies, attaching the inner members to the sides of the chassis being installed into the rack, and then re-installing or “stabbing” the inner members back into the rail subassemblies that are installed in the rack. One difficulty with stab-in rail assemblies is that a user typically has to align and insert both sides of the rail assembly simultaneously or get one side inserted and prevent the inserted side from disengaging while attempting to insert the other side. 
     Generally, end users prefer to have server information handling systems displace a small footprint since datacenter space comes at a premium. Within a server rack, information handling systems come in a variety of heights defined by a standardized rack unit, or “U,” such as a 1 U or 2 U chassis. However, the widths of all information handling systems and their associated rack mounting hardware must fit within a fixed value governed by the same rack standard. Therefore the only way to incorporate larger components or a higher quantity of components inside an information handling system without increasing its overall footprint within the rack is to increase its width. As a result, the rail assemblies used to support the chassis in the racks have tended to become narrower over time. The trend in the use of narrower rail assemblies is likely to continue. The narrower rail assemblies tend to make it more difficult to manipulate a chassis for installation into a rack. For example, one of the main challenges with stab-in rail assembly structures is properly aligning inner rail members back into rack rail subassemblies during installation or replacement of the chassis into the rack. Smaller-sized rails are difficult to handle and susceptible to physical damage in the event of application of force along axes that are not intended to withstand excessive force, such as with twisting movements. Small misalignments during a stab-in of a rail can damage the rail or put the chassis in an unsecure or unstable state. As the information handling system industry trends towards narrower slide rail profiles, proper alignment by an end user of inner members with a rail assembly during insertion of the chassis into the rack has become a greater challenge for the end user. 
     SUMMARY OF THE INVENTION 
     Therefore a need has arisen for a system and method which aids alignment of a rail inner member to a rail subassembly during insertion of an information handling system chassis into a server rack. 
     In accordance with the present invention, a system and method are provided which substantially reduce the disadvantages and problems associated with previous methods and systems for inserting an inner rail member into a rail subassembly to insert an information handling system chassis into server rack. A resting surface at an insertion end of an intermediate rail member accepts the inner rail member before insertion to aid alignment of opposing rail assemblies at a rack during insertion of an information handling system. 
     More specifically, a rack having plural slots holds an information handling system chassis in each slot with a pair of rail assemblies disposed at opposing sides of each slot. The rail assembly includes a subassembly coupled to the rack and having an intermediate member that extends out from the rack. An inner rail member slides into and withdraws from the intermediate rail member. The inner rail member couples to an information handling system chassis so that the chassis is inserted into the rack by inserting first and second inner rail members on opposing sides of the chassis into first and second intermediate rail members of rail subassemblies disposed on opposing sides of a slot in the rack. A resting surface extending from the lower portion of each intermediate rail member insertion end accepts the weight of the inner rail members during insertion of the chassis to aid alignment of the inner rail members with the intermediate rail members during a stab-in insertion of the inner rail members into the intermediate rail members. 
     The present invention provides a number of important technical advantages. One example of an important technical advantage is that inner rail members of a stab-in style slide rail are properly aligned with the aid of a landing pad guide, thus reducing the challenge faced by an end user who installs a stab-in style rail into a rail subassembly. The alignment and temporary resting place provided by the guide during the installation process reduces the risk of damage to the rail assembly and information handling system chassis by preventing the system from entering an unstable or unsecure state during installation. Increased stability during rail assembly for a stab-in chassis insertion helps to make more practical the use of narrow slide assembly profiles associated with larger information handling system chassis. Greater ease of assembly reduces the difficulty faced by end users when performing information handling system initial installation, maintenance or replacement at a server rack. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention may be better understood, and its numerous objects, features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. The use of the same reference number throughout the several figures designates a like or similar element. 
         FIG. 1  depicts a rack that holds plural information handling systems on stab-in rail assemblies; 
         FIG. 2  depicts a conventional stab-in rail assembly; and 
         FIG. 3  depicts a stab-in rail assembly having a resting place at the insertion end of an intermediate rail member that accepts an inner rail member during a stab-in insertion. 
     
    
    
     DETAILED DESCRIPTION 
     A resting surface at the insertion end of a rail assembly intermediate rail member aids stab-in assertion of an inner rail member that is coupled to an information handling system. For purposes of this disclosure, an information handling system may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components. 
     Referring now to  FIG. 1 , a rack  12  that holds plural information handling systems  10  on stab-in rail assemblies  14  is depicted. Rack  12  has an open front face and plural slots  16 , each slot sized to accept an information handling system  10 . On opposing interior sides of rack  12  at each slot  16 , a rail assembly couples to rack  12  to support an information handling system  10  so that the information handling system  10  slides into and out of the interior of rack  12 . Each information handling system  10  is built with plural processing components disposed in a housing, such as a CPU, RAM, a chipset and a hard disk drive. The processing components cooperate to perform a processing function, such as a server or storage function. 
     Each rail assembly  14  has a subassembly  18  coupled to rack  12  with an integrated intermediate rail member  20  and a detachable inner rail member  22 . Intermediate rail member  20  slides within subassembly  18  between a retracted position within the interior of rack  12  and an extended position at the exterior of rack  12 . Inner rail member  22  couples to opposing sides of information handling system  10  so that inner rail members  22  align to couple with intermediate rail members  20  extending from rail assemblies coupled in rack  12  at opposing sides of a slot  16 . To insert an information handling system  10  into a slot  16 , inner rail members  22  coupled to information handling system  10  are aligned with intermediate rail members  20  extending from rack  12  and stabbed into intermediate rail members  20 . Once engaged in intermediate rail members  20 , inner rail members  22  slide into intermediate rail members  20  which in turn slide into rail subassembly  18  until information handling system  10  is held within the interior of rack  12 . To remove an information handling system  10  from rack  12 , inner rail member  22  slides out of intermediate rail member  20  and disengages from intermediate rail  20 . 
     Referring now to  FIG. 2 , a conventional stab-in rail assembly is depicted. Intermediate rail member  20  extends outward to expose an insertion end  24 , which accepts inner rail member  22  between a lower runner  26  and an upper runner  28 . Since both lower runner  26  and upper runner  28  align with insertion end  24 , engaging inner rail member  22  at insertion end  24  generally calls for both top and bottom portions of inner rail member  22  to align simultaneously for the rail assemblies on both sides of a slot. Simultaneous alignment of inner rail member  22  at lower runner  26  and upper runner  28  tends to be difficult, especially with small-sized rail assemblies. If the rail assembly on one side assembles by stabbing inner rail member  22  through insertion end  24 , the process of assembling the rail assembly on the opposing side can introduce a twisting force that damages the rail assembly or information handling system. 
     Referring now to  FIG. 3 , a stab-in rail assembly is depicted having a resting surface  34  at the insertion end  24  of an intermediate rail member  20  that accepts an inner rail member  22  during a stab-in insertion. Resting surface  34  is a portion of intermediate rail member  20  that extends outward to provide a place for inner rail member  22  to land during stab-in insertion to intermediate rail member  20 . Resting surface  34  is an extension of the lower portion  30  of intermediate rail  20  by a greater distance than upper portion  32  extends so that inner rail member  22  lands on resting surface  34  to await insertion into intermediate rail member  20 . In one embodiment, resting surface  34  includes an extension of lower runner  26  so that a lower wheel  36  of inner rail member  22  helps to align inner rail member  22  with intermediate rail member  20  before a stab-in insertion brings an upper wheel  38  into upper runner  28  of upper portion  32 . In an alternative embodiment, a biasing device helps to obtain alignment of inner rail member  22  with intermediate rail member  20  to ease the insertion process. For example, a funnel shape  40 , indicated by dotted lines, is included at resting surface  34  to help guide inner rail member  22  to a proper position for insertion into intermediate rail member  20 . As another example, an arrangement of like and unlike poles of magnets can help to guide inner rail member  22  to a proper position for insertion into intermediate rail member  20 , such as by including a rotatable magnet on lower wheel. With each embodiment, the goal is to have resting surface  34  provide a temporary landing space for inner rail member  22  during a stab-in insertion so that stability is provided while rail assemblies on opposites sides of a slot are secured at both the upper and lower portions of intermediate rail members  20 . 
     Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as defined by the appended claims.