Patent Publication Number: US-8991949-B2

Title: Chassis drawer for modular information handling resources

Description:
TECHNICAL FIELD 
     The present disclosure relates to modular information handling systems. More specifically, embodiments of the disclosure provide systems and methods for a chassis drawer for providing access to modular information handling resources for addition and/or removal of such modular information handling resources. 
     BACKGROUND 
     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. 
     Oftentimes, information handling systems and other information handling resources (e.g., storage devices, input/output devices, and other peripheral devices) are each manufactured in a modular form factor and may be configured to be disposed in a chassis configured to receive such modular components. Such a chassis and its component modular information handling systems and information handling resources typically include various rails, carriers, and other mechanical components allowing for a person to add and remove the modular information handling systems and information handling resources from the chassis. In traditional modular systems, information handling resources (including hard disk drives) and their corresponding chassis bays, are typically accessed from a side of the chassis in which the information handling resources may be added or removed. However, because access may be limited to the periphery of the chassis, such an architecture may limit the density of modular components that may be disposed in a chassis. 
     SUMMARY 
     In accordance with the teachings of the present disclosure, the disadvantages and problems associated with traditional approaches to accessing modular information handling resources in a chassis have been substantially reduced or eliminated. 
     In accordance with embodiments of the present disclosure, a drawer for receiving components may comprise an inner member, and intermediate member, and a carrier member. The inner member may include two substantially planar and generally parallel opposite inner member sides defining a drawer height and a substantially planar inner member bottom generally perpendicular to the inner member sides and defining a drawer width. The intermediate member may be mechanically coupled to the inner member such that the intermediate member is configured to slide relative to the inner member in a direction generally perpendicular to the drawer height and the drawer width. The carrier member may be mechanically coupled to the intermediate member such that the carrier member is configured to slide relative to the inner member and the intermediate member in a direction generally perpendicular to the drawer height and the drawer width. The carrier member may comprise a substantially planar carrier member top generally parallel to the inner member bottom, a substantially planar carrier member bottom generally parallel to the carrier member top, a carrier spine mechanically coupled between the carrier member top and the carrier member bottom, a plurality of bays, each bay having one or more structural components for receiving a modular information handling resource and configured such that the bay is accessed for insertion or removal of the modular information handling resource via a carrier member side of the carrier member generally parallel to the inner member side, and at least one web generally parallel to the inner member sides and mechanically coupling the carrier member to the intermediate member such that when the drawer is translated to an open position, each of the plurality of bays is accessible. 
     In accordance with these and other embodiments of the present disclosure, an information handling system may include a chassis and a drawer for receiving components, comprising. The drawer may comprise an inner member, and intermediate member, and a carrier member. The inner member may be fixedly coupled to the chassis and include two substantially planar and generally parallel opposite inner member sides defining a drawer height and a substantially planar inner member bottom generally perpendicular to the inner member sides and defining a drawer width. The intermediate member may be mechanically coupled to the inner member such that the intermediate member is configured to slide relative to the inner member in a direction generally perpendicular to the drawer height and the drawer width. The carrier member may be mechanically coupled to the intermediate member such that the carrier member is configured to slide relative to the inner member and the intermediate member in a direction generally perpendicular to the drawer height and the drawer width. The carrier member may include a substantially planar carrier member top generally parallel to the inner member bottom, a substantially planar carrier member bottom generally parallel to the carrier member top, a carrier spine mechanically coupled between the carrier member top and the carrier member bottom, and a plurality of bays, each bay having one or more structural components for receiving a modular information handling resource and configured such that the bay is accessed for insertion or removal of the modular information handling resource via a carrier member side of the carrier member generally parallel to the inner member side, and at least one web generally parallel to the inner member sides and mechanically coupling the carrier member to the intermediate member such that when the drawer is translated to an open position, each of the plurality of bays is accessible. 
     In accordance with embodiments of the present disclosure, a method may include mechanically coupling an intermediate member to an inner member, wherein the inner member comprises two substantially planar and generally parallel opposite inner member sides defining a drawer height and a substantially planar inner member bottom generally perpendicular to the inner member sides and defining a drawer width, and the intermediate member is mechanically coupled to the inner member such that the intermediate member is configured to slide relative to the inner member in a direction generally perpendicular to the drawer height and the drawer width. The method may also include mechanically coupling a carrier member to the intermediate member such that the carrier member is configured to slide relative to the inner member and the intermediate member in a direction generally perpendicular to the drawer height and the drawer width, wherein the carrier member comprises a substantially planar carrier member top generally parallel to the inner member bottom, a substantially planar carrier member bottom generally parallel to the carrier member top, a carrier spine mechanically coupled between the carrier member top and the carrier member bottom, a plurality of bays, each bay having one or more structural components for receiving a modular information handling resource and configured such that the bay is accessed for insertion or removal of the modular information handling resource via a carrier member side of the carrier member generally parallel to the inner member side, and at least one web generally parallel to the inner member sides and mechanically coupling the carrier member to the intermediate member such that when the drawer is translated to an open position, each of the plurality of bays is accessible. 
     In accordance with these and other embodiments of the present disclosure, a backplane for electrically coupling modular information handling resources to one or more other information handling resources, may include a printed circuit board, a first plurality of slots, and a second plurality of slots. The printed circuit board may have a first surface and a second surface opposite the first surface. The first plurality of slots may be mounted to the first surface and the second plurality of slots may be mounted to the second surface, such that each of the second plurality of slots are offset from an adjacent slot of the first plurality of slots in a direction parallel to a plane defined by the first surface and each of the second plurality of slots are rotated approximately 180 degrees from an adjacent slot of the first plurality of slots. 
     In accordance with these and other embodiments of the present disclosure, a backplane for electrically coupling modular information handling resources to one or more other information handling resources, may include a printed circuit board, a first plurality of openings, a first plurality of slots, a second plurality of openings, and a second plurality of slots. The printed circuit board may have a first surface and a second surface opposite the first surface. The first plurality of openings may be formed in the first surface and the first plurality of slots mounted to the printed circuit board within the first plurality of openings. The second plurality of openings may be formed in the second surface and the second plurality of slots may be mounted to the printed circuit board within the second plurality of openings. 
     In accordance with these and other embodiments of the present disclosure, a system may include a structural member, a release latch, and a slider. The structural member may define at least a portion of a bay for receiving an information handling resource. The release latch may be mechanically coupled to the structural member. The slider may be slidably coupled to the structural member and mechanically coupled to the structural member by an ejection spring with an ejection spring force configured to bias the slider in a first position relative to the structural member in absence of a force other than the rejection spring force. The slider may configured to, when the information handling resource is inserted into the bay, slide relative to the structural member in a direction opposite the ejection spring force and away from the first position and engage with the release latch, such that when engaged with the release latch, the slider is biased in a second position away from the first position. 
     In accordance with these and other embodiments of the present disclosure, an information handling system, may include a chassis and a drawer mechanically coupled to the chassis. The chassis may have a plurality of bays. Each bay configured to receive an information handling resource and each bay may include a structural member, a release latch, and a slider. The structural member may define at least a portion of the bay. The release latch may be mechanically coupled to the structural member. The slider may be slidably coupled to the structural member and mechanically coupled to the structural member by an ejection spring with an ejection spring force configured to bias the slider in a first position relative to the structural member in absence of a force other than the rejection spring force. The slider may be configured to, when the information handling resource is inserted into the bay slide relative to the structural member in a direction opposite the ejection spring force and away from the first position and engage with the release latch, such that when engaged with the release latch, the slider is biased in a second position away from the first position. 
     In accordance with these and other embodiments of the present disclosure, a method may include sliding a slider slidably coupled to the structural member and mechanically coupled to the structural member by an ejection spring with an ejection spring force configured to bias the slider in a first position relative to the structural member in absence of a force other than the rejection spring force, wherein the sliding is in a direction opposite the ejection spring force and away from the first position, and wherein the structural member defines at least a portion of a bay for receiving an information handling resource. The method may also include engaging the slider with a release latch mechanically coupled to the structural member, such that when engaged with the release latch, the slider is biased in a second position away from the first position. 
     In accordance with these and other embodiments of the present disclosure, a drawer for receiving components may include a caddy tray and at least one caddy. The caddy tray may include a substantially planar caddy tray bottom defining a caddy tray depth and a caddy tray width. The at least one caddy may be mechanically coupled to the caddy tray via a hinge mechanically coupled to the caddy tray bottom such that the caddy pivots relative to the caddy tray about the hinge, the hinge having an axis generally parallel to the caddy tray depth, the at least one caddy having a plurality of bays, each bay having one or more structural components for receiving a modular information handling resource and configured such that the bay is accessed for insertion or removal of the modular information handling resource when the at least one caddy is pivoted from a closed position to an open position. 
     In accordance with these and other embodiments of the present disclosure, an information handling system may include a chassis and a drawer for receiving components. The drawer may include a caddy tray comprising a substantially planar caddy tray bottom defining a caddy tray depth and a caddy tray width. The drawer may also include at least one caddy mechanically coupled to the caddy tray via a hinge mechanically coupled to the caddy tray bottom such that the caddy pivots relative to the caddy tray about the hinge, the hinge having an axis generally parallel to the caddy tray depth, the at least one caddy having a plurality of bays, each bay having one or more structural components for receiving a modular information handling resource and configured such that the bay is accessed for insertion or removal of the modular information handling resource when the at least one caddy is pivoted from a closed position to an open position. The drawer may additionally include a drawer cover fixedly coupled to the caddy tray. The drawer may further include a drawer sleeve fixedly coupled to the chassis and slidably coupled to the drawer cover, such that the drawer cover slides relative to the drawer sleeve and such that when the drawer is translated to an open position relative to the chassis and when the at least one caddy is pivoted from a closed position to an open position, each of the plurality of bays is accessible. 
     In accordance with these and other embodiments of the present disclosure, a method comprising may include mechanically coupling a caddy tray to at least one caddy, wherein the caddy tray comprises a substantially planar caddy tray bottom defining a caddy tray depth and a caddy tray width and the at least one caddy is mechanically coupled to the caddy tray via a hinge mechanically coupled to the caddy tray bottom such that the caddy pivots relative to the caddy tray about the hinge, the hinge having an axis generally parallel to the caddy tray depth, the at least one caddy having a plurality of bays, each bay having one or more structural components for receiving a modular information handling resource and configured such that the bay is accessed for insertion or removal of the modular information handling resource when the at least one caddy is pivoted from a closed position to an open position. 
     Technical advantages of the present disclosure may be apparent to those of ordinary skill in the art in view of the following specification, claims, and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein: 
         FIG. 1  illustrates a perspective view of a chassis for receiving modular information handling resources, in accordance with embodiments of the present disclosure; 
         FIG. 2  illustrates a perspective view of an example chassis drawer for receiving modular information handling resources, the drawer in an open position, in accordance with embodiments of the present disclosure; 
         FIG. 3  illustrates a perspective view of an example chassis drawer for receiving modular information handling resources, the drawer in a closed position, in accordance with embodiments of the present disclosure; 
         FIG. 4  illustrates a perspective view of selected components of the chassis drawer depicted in  FIGS. 2 and 3 , in accordance with embodiments of the present disclosure; 
         FIG. 5  illustrates a perspective view of selected components of an example carrier member of the chassis drawer depicted in  FIGS. 2 and 3 , in accordance with embodiments of the present disclosure; 
         FIG. 6  illustrates a perspective view of an example center spine of the carrier member depicted in  FIG. 5 , in accordance with embodiments of the present disclosure; 
         FIG. 7  illustrates a cross-sectional elevation view of an example backplane for use in the chassis drawer depicted in  FIGS. 1-6 , in accordance with embodiments of the present disclosure; 
         FIG. 8  illustrates a cross-sectional elevation view of another example backplane for use in the chassis drawer depicted in  FIGS. 1-6 , in accordance with embodiments of the present disclosure; 
         FIG. 9  illustrates a cross-sectional elevation view of yet another example backplane for use in the chassis drawer depicted in  FIGS. 1-6 , in accordance with embodiments of the present disclosure; 
         FIG. 10  illustrates a perspective view of selected components of particular embodiments of the example backplane depicted in  FIG. 9 , in accordance with the present disclosure; 
         FIG. 11  illustrates a perspective view of the example backplane depicted in  FIG. 9  implementing the particular embodiments depicted in  FIG. 10 , in accordance with the present disclosure; 
         FIG. 12  illustrates a perspective view of selected components of other particular embodiments of the example backplane depicted in  FIG. 9 , in accordance with the present disclosure; 
         FIG. 13  illustrates a perspective view of selected components of yet other particular embodiments of the example backplane depicted in  FIG. 9 , in accordance with the present disclosure; 
         FIG. 14  illustrates a cross-sectional elevation view of yet another example backplane for use in the chassis drawer depicted in  FIGS. 1-6 , in accordance with embodiments of the present disclosure; 
         FIG. 15  illustrates a perspective view of selected components of the chassis drawer depicted in  FIGS. 2 and 3  for inserting and removing an information handling resource from an individual bay of the chassis drawer, in accordance with embodiments of the present disclosure; 
         FIGS. 16-19  illustrate various perspective views of selected components of the chassis drawer depicted in  FIGS. 2 and 3  depicting insertion of an information handling resource into an individual bay of the chassis drawer, in accordance with embodiments of the present disclosure; 
         FIG. 20  illustrates a perspective view of an alternative embodiment of a chassis drawer for receiving modular information handling resources, in accordance with embodiments of the present disclosure; 
         FIG. 21  illustrates a perspective view of an information handling resource caddy for use in the chassis drawer depicted in  FIG. 20 , in accordance with embodiments of the present disclosure; 
         FIG. 22  illustrates a side view of an information handling resource caddy for use in the chassis drawer depicted in  FIG. 20 , in accordance with embodiments of the present disclosure; 
         FIG. 23  illustrates a perspective view of a backplane for use in the chassis drawer depicted in  FIG. 20 , in accordance with embodiments of the present disclosure; and 
         FIG. 24  illustrates a block diagram of an example rail system for use in a modular chassis, as is known in the art. 
     
    
    
     DETAILED DESCRIPTION 
     Preferred embodiments and their advantages are best understood by reference to  FIGS. 1-23 , wherein like numbers are used to indicate like and corresponding parts. 
     For the 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, entertainment, or other purposes. For example, an information handling system may be a personal computer, a personal digital assistant (PDA), a consumer electronic device, 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 memory, one or more processing resources such as a central processing unit (CPU) or hardware or software control logic. Additional components of the information handling system may include one or more storage devices, one or more communications 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 busses operable to transmit communication between the various hardware components. 
     In this disclosure, the term “information handling resource” may broadly refer to any component system, device or apparatus of an information handling system, including without limitation processors, busses, memories, input-output devices and/or interfaces, storage resources, network interfaces, motherboards, electro-mechanical devices (e.g., fans), displays, and power supplies. 
       FIG. 1  illustrates a perspective view of a chassis  100  for receiving modular information handling resources, in accordance with embodiments of the present disclosure. Chassis  100  may be an enclosure that serves as a container for various information handling systems and information handling resources, and may be constructed from steel, aluminum, plastic, and/or any other suitable material. Although the term “chassis” is used, chassis  100  may also be referred to as a case, cabinet, tower, box, enclosure, and/or housing. In certain embodiments, chassis  100  may be configured to hold and/or provide power to a plurality of information handling systems and/or information handling resources. As depicted in  FIG. 1 , chassis  100  may include one or more drawers  102  for receiving information handling resources, as described in greater detail below. 
       FIGS. 2-6  depict various views of an example chassis drawer  102  for receiving modular information handling resources, in accordance with embodiments of the present disclosure.  FIG. 2  illustrates a perspective view of an example chassis drawer  102  for receiving modular information handling resources, wherein drawer  102  is in an open position drawn from chassis  100 , in accordance with embodiments of the present disclosure.  FIG. 3  illustrates a perspective view of chassis drawer  102  for receiving modular information handling resources, wherein drawer  102  is in a closed position relative to chassis  100 , in accordance with embodiments of the present disclosure.  FIG. 4  illustrates a perspective view of selected components of chassis drawer  102  depicted in  FIGS. 2 and 3 , in accordance with embodiments of the present disclosure.  FIG. 5  illustrates a perspective view of selected components of an example carrier member  108  of chassis drawer  102  depicted in  FIGS. 2 and 3 , in accordance with embodiments of the present disclosure.  FIG. 6  illustrates a perspective view of an example center spine  120  of carrier member  108  depicted in  FIG. 5 , in accordance with embodiments of the present disclosure. 
     As shown in  FIGS. 2-4 , chassis drawer  102  may comprise an inner member  104 , an intermediate member  106  mechanically coupled to inner member  104 , and a carrier member  108  mechanically coupled to intermediate member  106 . Inner member  104  may be constructed from steel, aluminum, plastic, and/or any other suitable material. Although inner member  104  may have any suitable size and/or shape, inner member  104  is depicted in the embodiments of  FIGS. 2-4  as having two substantially planar and parallel opposite sides defining a drawer height coupled to each other by a substantially planar bottom generally perpendicular to the sides defining a drawer width and a guide flange extending from and running perpendicular to and along the length of each side such that the flanges project towards each other. In some embodiments, inner member  104  may be mechanically coupled to the internal mechanical structure of chassis  100 , such that inner member  104  is fixed relative to chassis  100 . 
     Intermediate member  106  may be constructed from steel, aluminum, plastic, and/or any other suitable material. Although intermediate member  106  may have any suitable size and/or shape, intermediate member  106  is depicted in the embodiments of  FIGS. 2-4  as having two generally parallel and planar opposite sides coupled to each other by a substantially planar bottom generally perpendicular to the sides. The height of the sides and the width of the bottom may be such that the corresponding sides and bottom of inner member  104  provide a mechanical guide for intermediate member  106  as chassis drawer  102  is opened and closed. Intermediate member  106  may be mechanically coupled to inner member  104  via bearings and/or other mechanical components such that intermediate member  106  may slide relative to inner member  104  in a direction perpendicular to the drawer height and drawer width defined by inner member  104 . As shown in  FIG. 4 , intermediate member  106  may be limited in the distance it may be drawn from chassis  100  through any combination of suitable structural elements. For example, in the embodiments represented by  FIG. 4 , translational movement of intermediate member  106  from the chassis may be limited by flanges  146  extending from the sides of intermediate member  106  and towards each other and corresponding depressions  144  formed at the interior corner of inner member  104  defined by a side and flange of inner member  104 . Similarly, other mechanical components may restrict motion of intermediate member  106  relative to inner member  104  as chassis drawer  102  is translated from the open position to the closed position. For example, in the embodiments represented by  FIG. 4 , intermediate member  104  may have one or more spring-loaded cams  148  mounted to the an interior of the sides of intermediate member  104 . As chassis drawer  102  is translated from a closed position to an open position, a projection of cam  148  may, as a result of spring force, engage with a corresponding opening  150  of a flange  146  of inner member  104 . Accordingly, cam  148  may lock the motion of intermediate member  106  relative to inner member  104  until, upon translation of chassis drawer  102  from the open position to the closed position, carrier member  108  or another component of chassis drawer  102  engages with cam  148  to cause the projection of cam  148  to disengage from opening  150 , allowing intermediate member  106  to again slide relative to inner member  104 . 
     Carrier member  108  may be constructed from steel, aluminum, plastic, and/or any other suitable material. Although carrier member  108  may have any suitable size and/or shape, carrier member  108  is depicted in the embodiments of  FIGS. 2-5  as having a substantially planar top  114  and a substantially planar bottom  116  generally parallel to each other defining a width and depth of carrier member  108 , the top  114  and bottom  116  mechanically coupled to each other by a carrier spine  120  defining a height of carrier member  108 , such that top  114  and bottom  116  are generally perpendicular to the sides of intermediate member  106 . In some embodiments, carrier spine  120  may run a portion of the depth of carrier member  108  such that in such portion, carrier spine  120  is located at approximately the center of the width of carrier member  108 . Carrier member  108  may also include a face  110  mechanically affixed to top  114 , bottom  116 , and/or carrier spine  120 . As shown in  FIGS. 2-5 , top  114  may include one or more openings (e.g., above bays  112 ) allowing for gaseous fluid to pass through. Similarly, bottom  116  may also include one or more openings (e.g., below bays  112 ) allowing for gaseous fluid to pass through. 
     In some embodiments, face  110  may be substantially equal to the width of carrier member  108  and substantially equal to the height of carrier member  108 . In these and other embodiments, face  110  may include handles, pull tabs, and/or other features allowing a person to pull on face  110  in order to translate chassis drawer  102  from a closed position to an open position in a direction generally parallel to the depth of top  114  and bottom  116 . In these and other embodiments, face  110  may include a grill, vent, and/or other opening allowing gaseous fluid to enter and/or exit through face  110 . 
     As shown in  FIGS. 2 and 4 , each side of carrier member  108  (e.g., portions of carrier member  108  between the edges of top  114  and bottom  116  and parallel to carrier spine  120 ) may include a web  130  configured to mechanically couple carrier member  108  to intermediate member  106 , as well as openings for a plurality of bays  112 . As shown in the embodiments represented by  FIG. 4 , web  130  of carrier member  108  may have openings  132  and  136  configured to engage with bearings  134  and  138 , respectively of intermediate member  106 . Accordingly, openings  132  and  136  may restrict movement of carrier member  108  relative to intermediate member  106 . 
     Similarly, other mechanical components may restrict motion of carrier member  108  relative to intermediate member  106  as chassis drawer  102  is translated from the closed position to the open position. For example, in the embodiments represented by  FIG. 4 , carrier member  108  may have a cam  142  mechanically coupled to one or both of the opposite sides of carrier member  108 . A spring force of cam  142  may bias cam  142  such that portion thereof extends through a corresponding opening  140  of carrier member  108 . While chassis drawer  102  is translated from an open position to a closed position, cam  142  may be rotated via mechanical interaction of guide flanges of inner member  104  with an end of cam  142  extending through opening  140 . Such rotation may cause an opposite end of cam  142  to engage with cam  148  of inner member  104  (e.g. near opening  150 ), thus restricting movement of carrier member  108  relative to intermediate member  106  in the outward direction of chassis drawer  102 . Accordingly, when chassis drawer  102  is translated from a closed position to an open position, cam  142  may remain engaged with cam  148  until such time as carrier member  108  is withdrawn sufficiently so as to allow cam  142  to rotate through opening  140  to its spring-biased position, such that chassis member  108  is movable relative to intermediate member  106 . 
     Also, as depicted in  FIG. 4 , openings  132  and/or  136  may be sloped so that as chassis drawer  102  is opened, the engagement of bearings  134  and/or  138  with openings  132  and/or  136 , respectively, may cause carrier member  108  to tilt slightly upward from chassis  100  to face  110 , in order to counteract the downward force caused by the weight of chassis drawer  102  and the various information handling resources disposed therein. 
     In the embodiments represented by  FIG. 6 , carrier spine  120  may include a substantially planar center member  122  and two flanges  124  generally perpendicular to center member  122  and projecting from each other on a top edge of center member  122  and two flanges  124  generally perpendicular to center member  122  and projecting from each other on a bottom edge of center member  122 , the bottom edge opposite the top edge. Accordingly, carrier spine  120  may be structurally similar to an I-beam. In some embodiments, center member  122  and flanges  124  may be formed from the same piece of material. In other embodiments, center member  122  and flanges  124  may be formed from different pieces of material. For example, in some embodiments, carrier spine  120  may be constructed of two U-shaped pieces configured back to back and attached to each other via adhesive and/or mechanical fasteners. In these and other embodiments, flanges  124  may include one or more openings for receiving mechanical fasteners to mechanically couple flanges  124  to top  114  or bottom  116  via corresponding openings in top  114  or bottom  116 . 
     As shown in  FIGS. 4-6 , a backplane  126  may be mechanically coupled to carrier spine  120 . Backplane  126  may comprise any system, device, or apparatus configured to interconnect modular information handling resources inserted into bays  112  (e.g., hard disk drives) with each other and/or to other information handling resources of chassis  100 . Accordingly, backplane  126  may include slots  128  and/or other connectors configured to receive corresponding electrical connectors of information handling resources in order to electrically couple information handling resources inserted into bays  112  to backplane  126 . In some embodiments, backplane  126  may be configured to receive information handling resources on each side of center member  122 , such that information handling resources on opposite sides of center member  122  are oriented “back-to-back” with respect to each other. In these and other embodiments, backplane  126  may comprise either a single printed circuit board coupled to center spine  120  with slots  128  mounted to each side or may comprise two electrically separate printed circuit boards coupled to center spine  120  in a back-to-back manner with slots  128  mounted on each printed circuit board. In some embodiments, one or more printed circuit boards comprising backplane  126  may form all or a portion of center member  122  and may comprise all or a portion of the mechanical structure for supporting the various flanges  124  of carrier spine  120 . 
     In some embodiments, all slots  128  of backplane  126  may be configured to receive identical or similar information handling resources having substantially similar form factors and/or functionality (e.g., 2.5-inch hard disk drives). In other embodiments, some slots  128  may be configured to receive an information handling resource different in form factor and/or functionality than that for which another slot  128  is configured. 
     As shown in  FIG. 2 , chassis drawer  102  may have an interface connector  118  configured to electrically couple to backplane  126  when chassis drawer  102  is closed thus providing electrical coupling between information handling resources disposed in bays  112  and other information handling resources of chassis  100 . 
     As shown in  FIG. 2 , carrier member  108  may have a plurality of bays  112  opening to each side of carrier member  108 . Each of such bays  112  may be defined by an associated backplane  126  and one or more structural elements of carrier member  108 . Accordingly, a bay  112  may include a suitable combination of structural elements configured to mechanically mate with an information handling resource to allow components of the information handling resource to electrically couple to backplane  126  when such information handling resource is received into the bay  112 . A bay  112  may also be configured to allow modular information handling resources to be easily inserted and removed from the bay  112  as desired by a user. 
     Although carrier member  108  may be constructed so as to support any suitable arrangement of bays  112 , in the embodiments represented by  FIGS. 2 and 4 , carrier member  108  is configured with 16 bays  112 , eight on each side of carrier spine  120  and arranged on each side of carrier spine  120  such that two drives may be oriented one over the other in each of four openings. 
     In some embodiments, all bays  112  of carrier member  108  may be configured to receive identical or similar information handling resources having substantially similar form factors and/or functionality (e.g., 2.5-inch hard disk drives). In other embodiments, some bays  112  may be configured to receive an information handling resource different in form factor and/or functionality than that for which another bay  112  is configured. 
     Accordingly, drawer  102  may be drawn open allowing full-extension of carrier member  108  such that a person may access bays  112  to add and/or remove information handling resources from drawer  102 . In addition, drawer  102  may be closed such that carrier member  108  is substantially telescoped within the depth of inner member  104  such that face  110  is generally parallel with a side of chassis  100 . 
     One or more advantages of chassis drawer  102  may be illustrated by referring to drawer slide  10  depicted in  FIG. 24 . As shown in  FIG. 24 , traditional full-extension drawer slides comprise an inner member  12 , an intermediate member  14 , and an external member  16 . Typically, when coupled to a drawer, external member  16  runs a substantial portion of the depth of the side of the drawer. Thus, such an arrangement would make a drawer with side access to contents of the drawer difficult to construct, as the sides would need to be made larger in height to accommodate both the drawer slide and access to contents. Advantageously, chassis drawer  102  as described herein provides for full extension of a drawer, while essentially moving most of the structural support provided by an external member of a drawer slide to carrier spine  120  of chassis drawer  102 , thus providing access to the sides of chassis drawer  102  while maintaining height of chassis drawer  102  substantially equal to that of the information handling resources to be installed in chassis drawer  102 . 
     As described above, backplane  126  may be configured in any suitable manner for receiving information handling resources on each of the two sides of backplane  126 . Examples of various embodiments of backplane  126  are described in greater detail below with respect to  FIGS. 7-14 . 
       FIG. 7  illustrates a cross-sectional elevation view of an example backplane  126 , in accordance with embodiments of the present disclosure. In the example shown in  FIG. 7 , backplane  126  may comprise two printed circuit boards each having slots  128  mounted to a surface thereof. Such printed circuit boards may be oriented back to back, such that modular information handling resources may be inserted on the opposite sides of backplane  126 . 
       FIG. 8  illustrates a cross-sectional elevation view of another example backplane  126 , in accordance with embodiments of the present disclosure. In the example shown in  FIG. 8 , backplane  126  may comprise a single printed circuit board having slots  128  mounted to each surface thereof. Thus, by using a single printed circuit board, rather than two printed circuit boards as shown in  FIG. 7 , the example backplane  126  of  FIG. 8  may conserve space and/or may be less costly to produce. In order to accommodate information handling resources of a similar form factor in the slots  128  mounted to each surface, slots  128  on a first surface of the printed circuit board may be offset from adjacent slots  128  on an opposite second surface of the second printed circuit board such that mounting features of each slot  128  may pass through backplane  126 . In addition, slots  128  on the first surface of the first printed circuit board, in addition to being offset from adjacent slots  128  on the opposite second surface of the second printed circuit board, may also be rotated approximately 180 degrees from adjacent slots  128  on the opposite second surface. Such rotation of slots  128  may be useful for information handling resources having connectors configured to mate with slots  128 , wherein such connectors are arranged along only a portion of a rear edge of such information handling resource, thus potentially reducing the physical height required by the example backplane  126  depicted in  FIG. 8  over embodiments in which such rotation is not employed. 
       FIG. 9  illustrates a cross-sectional elevation view of yet another example backplane  126 , in accordance with embodiments of the present disclosure. In the example shown in  FIG. 9 , backplane  126  may comprise two or more printed circuit boards each having slots  128  mounted to a surface thereof. In addition, the two or more printed circuit boards of backplane  126  may be oriented and/or may have openings formed therein such that as so oriented, the printed circuit boards define openings in backplane  126  allowing slots  128  to pass through such that the printed circuit boards and their slots  128  are in a nested, overlapping configuration within each other, rather than a non-overlapping configuration, such as that depicted in  FIG. 7 . In other words, in the example backplane  126  of  FIG. 9 , backplane  126  includes at least a first printed circuit board and a second printed circuit board, the first printed circuit board having at least a first slot  128  mounted to a first surface of the first printed circuit board and the second printed circuit board having at least a second slot  128  mounted to a second surface of the second printed circuit board. The first printed circuit board and the second printed circuit board are arranged such that the first slot passes through a plane defined by the second surface and the second slot passes through a plane defined by the first surface. Example embodiments of backplane  126  depicted in  FIG. 9  are illustrated in  FIGS. 10-13 . 
       FIG. 10  illustrates a perspective view of selected components of particular embodiments of the example backplane  126  depicted in  FIG. 9 , in accordance with the present disclosure.  FIG. 11  illustrates a perspective view of the example backplane  126  depicted in  FIG. 9  implementing the particular embodiments depicted in  FIG. 10 , in accordance with the present disclosure. As shown in  FIGS. 10 and 11 , backplane  126  may comprise two printed circuit boards  170  each having slots  128  mounted to a surface thereof and having one or more openings  172  formed therein. The two printed circuit boards may be oriented relative to each other such that slots  128  on one of the printed circuit boards  170  may pass through openings  172  of the other printed circuit board  170 , and vice versa, as shown in  FIG. 11 . 
       FIG. 12  illustrates a perspective view of selected components of other particular embodiments of the example backplane  126  depicted in  FIG. 9 , in accordance with the present disclosure. In the particular embodiments represented by  FIG. 12 , backplane  126  may comprise two printed circuit boards  174  (for clarity of exposition, only one printed circuit board  174  is depicted in  FIG. 12 ). Each printed circuit board  174  may comprise a plurality of forks  176  each having one or more slots  128  mounted to a surface thereof and the various forks  176  defining openings  177 . The two printed circuit boards may be oriented relative to each other such that slots  128  on one of the printed circuit boards  174  may pass through openings  177  of the other printed circuit board  174 , and vice versa, in a manner similar to that shown in  FIG. 11 . 
       FIG. 13  illustrates a perspective view of selected components of yet other particular embodiments of the example backplane  126  depicted in  FIG. 9 , in accordance with the present disclosure. In the particular embodiments represented by  FIG. 13 , backplane  126  may comprise two or more printed circuit boards  178  (for clarity of exposition, only two printed circuit boards  178  having substantially co-planar surfaces with slots  128  mounted to such surfaces are shown in  FIG. 13 ). The two or more printed circuit boards may be oriented relative to each other such that slots  128  on one of the printed circuit boards  178  may pass through a plane defined by the mounting surface of the other printed circuit board  178 , and vice versa, in a manner similar to that shown in  FIG. 11 . 
     In the embodiments described above with respect to  FIGS. 9-13 , in order to accommodate information handling resources of a similar form factor in the slots  128  mounted to each side of backplane  126 , slots  128  on one printed circuit board of backplane  126  may be offset from adjacent slots  128  on an opposite printed circuit board of backplane  126 . In addition, slots  128  on one printed circuit board of backplane  126 , in addition to being offset from adjacent slots  128  on the opposite printed circuit board of backplane  126 , may also be rotated approximately 180 degrees from adjacent slots  128  of the opposite printed circuit board. Such rotation of slots  128  may be useful for information handling resources having connectors configured to mate with slots  128 , wherein such connectors are arranged along only a portion of a rear edge of such information handling resource, thus potentially reducing the physical height required by the example backplane  126  depicted in  FIG. 9-13  over embodiments in which such rotation is not employed. 
       FIG. 14  illustrates a perspective view of selected components of yet another example backplane  126 , in accordance with the present disclosure. In the example shown in  FIG. 14 , backplane  126  may comprise a single printed circuit board  180 . Printed circuit board  180  may have a plurality of openings  184  formed in recessed areas below the surfaces on each side of printed circuit board  180  wherein slots  128  may be mounted. For example, printed circuit board layers may be omitted or removed in those areas in which slots  128  reside. In order to accommodate information handling resources of a similar form factor in opposite facing slots  128  of printed circuit board  180 , slots  128  facing a first direction on printed circuit board  180  may be offset from opposite facing adjacent slots  128 . In addition, slots  128  facing a first direction, in addition to being offset from opposite facing adjacent slots  128 , may also be rotated approximately 180 degrees from opposite facing adjacent slots  128 . Such rotation of slots  128  may be useful for information handling resources having connectors configured to mate with slots  128 , wherein such connectors are arranged along only a portion of a rear edge of such information handling resource, thus potentially reducing the physical height required by the example backplane  126  depicted in  FIG. 14  over embodiments in which such rotation is not employed. 
     The various embodiments depicted in  FIGS. 9-14  may have further advantages over the embodiments depicted in  FIGS. 7 and 8 . For example, the embodiments represented by  FIGS. 9-14  may provide a more compact layout of backplane  126 , slots  128 , and information handling resources than the embodiments represented by  FIGS. 7 and 8 . 
     As described above, chassis drawer  102  may be utilized in order to provide for addition and removal of information handling resources from chassis  100 . To illustrate addition and removal of an information handling resource from a bay  112  defined by chassis drawer  102 , reference is made to  FIGS. 15-19 .  FIG. 15  illustrates a perspective view of selected components of chassis drawer  102  for inserting and removing an information handling resource from an individual bay  112  of chassis drawer  102 , in accordance with embodiments of the present disclosure.  FIGS. 16-19  illustrate various perspective views of selected components of chassis drawer  102  depicting insertion of an information handling resource into an individual bay  112  of chassis drawer  102 , in accordance with embodiments of the present disclosure. 
     As shown in  FIGS. 15-19 , chassis drawer  102  may include a plurality of support members  202 , such that laterally adjacent bays  112  (e.g., bays  112  adjacent in a direction of the depth of carrier member  108 ) are separated by a support member  202 . In addition, each support member  202  may have a plurality of guide flanges  214  for mechanically guiding an information handling resource into and out of a bay  112 . In some embodiments, vertically adjacent bays  112  (e.g., bays  112  adjacent in a direction of the height of chassis drawer  102 ) may be separated by one or more guide flanges  214 . Accordingly, support members  202  and their various guide flanges  214  (as well as, in some embodiments, backplane  126  and slots  128 ) may be appropriately sized, shaped, and arranged relative to each other so as to define the plurality of bays  112 . 
     A support member  202  may have mechanically coupled thereto a slider  208  and slider bearings  204 . A slider  208  may comprise one or more openings  224  configured to engage with bearings  204  such that slider  208  may move in and out of bay  112  substantially in a direction of the width of chassis drawer  102 , with such movement limited by the size of openings  224 . A support member  202  of a bay  112  may also comprise one or more vibrational dampers  212  such that the one or more vibrational dampers  212  are opposite a slider  208  mechanically coupled to an opposing support member  202  defining the same bay  112 . As their name suggests, vibrational dampers  212  may dampen vibration generated by an information handling resource disposed in a bay  112  and/or generated elsewhere in chassis  100 . 
     As shown in  FIG. 17 , an ejection spring  222  may be coupled between support member  202  and slider  208  such that the spring force of ejection spring  222  biases slider  208  to a particular position relative to support member  202  in the absence of force other than the spring force of ejection spring  222 . 
     As shown in  FIG. 16 , an information handling resource  220  (e.g., a hard disk drive) may be inserted into a bay  112 , where its vertical and lateral movement may be restricted by guide flanges  214 , slider  208 , and/or vibrational dampers  212  such that information handling resource  220  moves substantially in the direction of the width of chassis drawer  102 . During insertion, a force may be applied (e.g., by a person) to translate the information handling resource into a bay  112  until such time as information handling resource  220  mechanically engages with a slide flange  216  of slider  208 . 
     After information handling resource  220  engages with slide flange  216 , the force inserting information handling resource  220  into bay  112  may also cause slider  208  to slide about bearings  204  of support member  202  in the same direction of the motion of information handling resource  220 , provided that such force is greater than the spring force of ejection spring  222 . 
     As shown in  FIGS. 17 and 18 , support member  202  may include a retention spring  225 . Retention spring  225  may be mechanically coupled to slider  208  such that as slider  208  slides relative to support member  202 , the motion of retention spring  225  in the direction of motion of slider  208  is fixed relative to slider  208 . As shown in  FIGS. 17 and 18 , slider  208  may include a retention spring opening  227  configured to receive a flange  226  of retention spring  225 . Retention spring  225  may have a spring force such that in the absence of forces other than the spring force, retention spring  225  is biased such that flange  226  does not engage with retention spring opening  227 . However, support member  202  may include a spring engagement feature  229  (e.g., a structural contour formed in support member  202 ) configured to overcome the spring force, such that as slider  208  is translated during insertion of information handling resource  220 , flange  226  engages with retention spring opening  227 . Accordingly, as information handling resource  220  is inserted into bay  112  and causes slider  208  to translate relative to support member  202 , flange  226  of retention spring  225  may engage with a corresponding feature (e.g., an opening) present on information handling resource  220 , thereby preventing or reducing motion of information handling resource  220  relative to slider  208  while flange  226  is engaged with such opening. 
     As shown in  FIGS. 17 and 19 , slider  208  may also include a slider post  209  coupled thereto and projecting therefrom. In addition, support member  202  may have mechanically coupled thereto a release latch  210  and bearings  206 . Release latch  210  may comprise one or more openings  228  configured to engage with bearings  206  such that slider  208  may move substantially in a direction of the height of chassis drawer  102 , with such movement limited by the size of openings  228 . 
     As shown in  FIGS. 17 and 19 , a latch return spring  230  may be coupled between support member  202  and release latch  210  such that the spring force of latch return spring  230  biases slider release latch  210  to a particular position relative to support member  202  in the absence of force other than the spring force of latch return spring  230 . 
     As information handling resource  220  is further inserted into bay  112  causing further translation of slider  208 , slider post  209  may engage with release latch  210 , such that the force of engagement between release latch  210  and slider post  209  overcomes the spring force of ejection spring  222 , thus locking slider  208  (and likewise information handling resource  220 ) into a fixed position relative to support member  202 , as depicted in  FIG. 19 . For example, in some embodiments release latch  210  may have a projection  231  appropriately sized and shaped such that as information handling resource  220  is inserted, slider post  209  engages with a slope of projection  231  that causes release latch  210  to move in a direction opposite of the spring force of latch return spring  230  and then engages with a valley of projection  231  such that the spring force of latch return spring  230  causes release latch  210  to return to its original position and engage with latch post  209  to prevent the spring force of ejection spring  222  from ejecting slider  208 . In some embodiments, as slider post  209  engages with release latch  210 , information handling resource  220  may engage with a slot  128 , thus electrically coupling information handling resource  220  to backplane  126 . 
     To remove information handling resource  220  from bay  112 , a user may actuate release latch  210 , for example, by applying a downward force on release latch flange  233  in a direction opposite to the spring force of latch return spring  230 . As a result of such actuation, slider post  209  may disengage from release latch  210 , causing slider  208  to eject under the force of ejection spring  222 . As slider  208  translates under the force of ejection spring  222 , the force of retention spring  225  causes flange  226  to disengage from information handling resource  220 . As a result, information handling resource  220  may be partially ejected from bay  112 , allowing a user to continue removal of information handling resource  220  by applying the necessary force. 
     Although chassis drawer  102  as described above may provide many advantages in terms of cost, density, and other factors, installations of a chassis may exist rendering usage of chassis drawer  102  impractical. For example, if a chassis were placed in a corner of a room, a wall of the room may prevent physical access to the sides of chassis drawer  102 , thus preventing access to bays  112  for addition and removal of information handling resources.  FIGS. 20-23  depict various selected components of a chassis drawer  302  for receiving modular information handling resources. 
       FIG. 20  illustrates a perspective view of a chassis drawer  301  for receiving modular information handling resources, in accordance with embodiments of the present disclosure. As shown in  FIG. 20 , chassis drawer  301  may comprise a plurality of information handling resource caddies  302 , a drawer cover  308 , a drawer sleeve  310 , and a caddy tray  316 . 
     Caddy tray  316  may be constructed from steel, aluminum, plastic, and/or any other suitable material. Although caddy tray  316  may have any suitable size and/or shape, caddy tray  316  is depicted in the embodiments of  FIG. 20  as having a substantially planar bottom  318  defining a width and depth of caddy tray  316 . Caddy tray  316  may also include a face  320  mechanically affixed to bottom  318 . Face  320  may be substantially planar and may further be generally perpendicular to bottom  318 . 
     In some embodiments, face  320  may be substantially equal to the width of caddy tray  316  and may define a height of caddy tray  316 . In these and other embodiments, face  320  may include handles, pull tabs, and/or other features allowing a person to pull on face  320  in order to translate chassis drawer  301  from a closed position to an open position in a direction generally parallel to the depth of bottom  318 . In these and other embodiments, face  320  may include a grill, vent, and/or other opening allowing gaseous fluid to enter and/or exit through face  320 . 
     Caddy tray  316  may be adapted to hold and structurally support one or more caddies  302  and information handling resources  220  disposed in such caddies  302 . A caddy  302  may be coupled to caddy tray  316  via a hinge  305 . Hinge  305  may be located along an edge of bottom  318  and may have an axis generally parallel to the depth of caddy tray  316 . Thus, a caddy  302  may pivot about hinge  305  relative to caddy tray  316 . In the embodiments represented by  FIG. 20 , a caddy tray  316  may have coupled thereto two opposite facing caddies  302 , such that when pivoted about their respective hinges  304 , caddies  302  rotate about generally parallel axes, but in opposite radial directions. 
     As also shown in  FIG. 20 , a caddy  302  may have a bearing  304  configured to engage with a corresponding arcuate opening  306  of face  320 . Accordingly, the size of opening  306  may limit the radial motion of a caddy  302  about its corresponding hinge  305 . In addition, opening  306  may include a downward projection  307  or other mechanical structure in which bearing  304  may rest in order to allow caddy  302  to remain in an open position while the bays  330  of such caddy  302  are accessed. 
     Chassis drawer  301  may also include a drawer cover  308  fixedly coupled to caddy tray  316 . Drawer cover  308  may also be slidably coupled to drawer sleeve  310  fixedly coupled to a chassis (e.g., chassis  100 ) such that drawer  308  (and caddy tray  316  fixedly coupled thereto) may slide relative to drawer sleeve  310  in a direction generally parallel to the depth of caddy tray  316  to translate chassis drawer  301  between an open position relative to the chassis and a closed position (e.g., in which face  320  is substantially flush or even with a side of the chassis). In some embodiments, drawer sleeve  310  may include flanges  311  or other structural elements for guiding the motion of drawer cover  308  and/or caddy tray  316  relative to drawer sleeve  310 . 
     Further, chassis drawer  301  may have one or more interface connectors  309  configured to electrically couple to backplane  326  (depicted in greater detail in  FIGS. 21-23 ) thus providing electrical coupling between information handling resources  220  disposed in caddies  302  and other information handling resources of a chassis. 
     Accordingly, in the embodiments represented by  FIG. 20 , drawer  301  may allow a user to slide drawer  301  from a chassis and access drives from a top of drawer  301  by appropriately applying force to a caddy  302  (e.g., via bearing  304 ) to rotate such caddy  302  to expose bays  330  thereof. 
       FIGS. 21 and 22  illustrate a perspective view and a side view, respectively, of a caddy  302 , in accordance with embodiments of the present disclosure. As shown in  FIGS. 21 and 22 , a backplane  326  may be mechanically coupled to caddy  302 . Backplane  326  may comprise any system, device, or apparatus configured to interconnect modular information handling resources inserted into bays  330  of caddy  302  (e.g., hard disk drives) with each other and/or to other information handling resources of a chassis. Accordingly, backplane  326  may include slots  328  and/or other connectors configured to receive corresponding electrical connectors of information handling resources in order to electrically couple information handling resources inserted into bays  330  to backplane  326 . In some embodiments, backplane  326  may have structure and/or functionality identical or similar to that of backplane  126  described above. 
     In some embodiments, all slots  328  of backplane  326  may be configured to receive identical or similar information handling resources having substantially similar form factors and/or functionality (e.g., 2.5-inch hard disk drives). In other embodiments, some slots  328  may be configured to receive an information handling resource different in form factor and/or functionality than that for which another slot  328  is configured. In these and other embodiments, slots  328  may have structure and/or functionality identical or similar to that of slots  128  described above. 
     As shown in  FIGS. 21 and 22 , one or more structural features of caddy  302  may define the plurality of bays  330  for receiving information handling resources  220 . For example, caddy  302  may include a plurality of support members  312 , such that laterally adjacent bays  330  (e.g., bays  330  adjacent in a direction of the depth of caddy tray  316 ) are separated by a support member  312 . In addition, each support member  312  may have a plurality of structural features (e.g., guide flanges) for mechanically guiding an information handling resource  220  into and out of a bay  330 . In some embodiments, vertically adjacent bays  330  (e.g., bays  330  adjacent in a direction of the height of face  320 ) may be separated by one or more structural features (e.g., guide flanges). In addition, bays  330  may be defined by an associated backplane  326  in addition to one or more structural elements of caddy  302 . Accordingly, a bay  330  may include a suitable combination of structural elements configured to mechanically mate with an information handling resource  220  to allow components of the information handling resource  220  to electrically couple to backplane  326  when such information handling resource is received into the bay  330 . A bay  330  may also be configured to allow modular information handling resources  220  to be easily inserted and removed from the bay  330  as desired by a user. 
     Although caddy  302  may be constructed so as to support any suitable arrangement of bays  330 , in the embodiments represented by  FIGS. 20-22 , caddy  302  is configured with eight bays  330 , such that two drives may be oriented one over the other in each of four openings. 
     In some embodiments, all bays  330  of caddy  302  may be configured to receive identical or similar information handling resources  220  having substantially similar form factors and/or functionality (e.g., 2.5-inch hard disk drives). In other embodiments, some bays  330  may be configured to receive an information handling resource  220  different in form factor and/or functionality than that for which another bay  330  is configured. 
       FIG. 23  illustrates a perspective view of a backplane  326 , in accordance with embodiments of the present disclosure. As shown in  FIG. 23 , backplane  326  may include a tail  314  for carrying conductive traces for electrically coupling slots  328  to one or more other information resources of a chassis. 
     Although the present disclosure 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 the scope of the disclosure as defined by the appended claims.