Abstract:
The invention relates to systems and processes for securably retaining a device within an equipment rack. A device carrier is configured to retain the device having a maximum height, such that a combined height of the device carrier and the device retained therein is not substantially greater than the maximum height of the device. A rack-mountable tray includes an aperture to accommodate the device carrier with a device retained therein. The device carrier is securable to the rack-mountable tray, such that the device retained therein can be securably retained to the equipment rack by a combination of the device carrier and the rack-mountable tray. Beneficially, a combined height of the device, the device carrier and the rack-mountable tray is not substantially greater than the maximum height of the device.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/387,585 entitled “Low-Clearance Rack Mount Adaptor,” filed on Sep. 29, 2010, and incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    Equipment designed to be placed in an electronic equipment rack is typically described as rack-mount, a rack-mount instrument, a rack mounted system, a rack mount chassis, a sub-rack, rack mountable, or occasionally simply a shelf. The height of the electronic modules adapted for rack mount is also standardized in a unit referred to as a standard rack unit or “U.” Presently, standard rack units are defined as multiples of 1.75 inches (4.445 cm). Such units are also widely used for computer server equipment, allowing for dense hardware configurations without occupying excessive floor space or requiring shelving. 
         [0003]    Typically, a piece of equipment being installed in such an equipment rack has a front panel height that is somewhat less than an allotted number of rack units. For example, the front panel height is generally at least about 1/32-inch (0.031″) less than the allotted number of rack units. Thus, a  1 U rack-mount computer is not 1.75 inches (44.4 mm) tall. Rather, the unit is about 1.719 inches (43.7 mm) tall. Similarly, a  2 U rack-mount device would be about 3.469 inches (88.1 mm) instead of 2×1.75=3.5 inches (88.9 mm). Such a gap allows for some clearance that can be allocated above and below an installed piece of equipment. Such clearance in the overall height of a device is advantageous such that the device may be inserted and removed without binding on the adjacent equipment or upper and lower rack supports. 
         [0004]    Many devices are designed with rack mounting in mind. Such devices typically include some sort of mounting flange or flanges to allow for direct mounting within a standardized equipment rack. Such flanges may extend laterally along a front panel of the device, positioned to abut vertical side rails of the equipment rack. The flanges may include holes and/or slots positioned for alignment with corresponding mounting holes/slots of the equipment rack. Fasteners can be used to attach the flanges to the equipment rack, thus securing the device at a desired height, in place within the rack. 
         [0005]    Other devices are not specifically designed with features for direct rack mounting. Nevertheless, such devices are routinely mounted within such racks, using ancillary mounting hardware, such as a tray or shelf Quite often, such tray or shelf mounting is anticipated and such devices are provided with suitable heights to accommodate mounting according to standard rack units (i.e., allowing for the typical clearance, i.e., 1/32 inch, and additional clearance for a supporting shelf or tray, such as a thickness of a bottom shelf of such a shelf . 
       SUMMARY 
       [0006]    In one aspect, a low-clearance rack mounting adapter includes at least one device carrier. The device carrier includes an open frame having a horizontal support and at least one tray mounting flange. The device carrier also includes at least one device-mounting strap securably attached to the open frame. The at least one device-mounting strap and the horizontal support are configured to retain a device having a maximum height therebetween. Preferably, a combined height of the device retained within the device carrier is not substantially greater than the maximum height of the device. The rack mounting adapter also includes a rack-mountable tray defining at least one aperture configured accommodate the at least one device carrier. The rack-mountable tray also has at least one surface configured to accommodate the at least one tray mounting flange. Beneficially, the rack-mountable tray secures the device carrier and device retained therein with respect to an equipment rack without substantially adding to the maximum height of the device. 
         [0007]    In another aspect, a process for securing a device within an equipment rack, includes positioning the device within an open frame of a device carrier, the device having a maximum height. The device is secured with respect to the device carrier, such that the combined height of the device and the device carrier is not substantially greater than the maximum height of the device. The device carrier with the device secured thereto, is secured to a rack-mounted tray. Beneficially a combined height of the device, the device carrier and the rack-mounted tray is not substantially greater than the maximum height of the device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The foregoing and other objects, features and advantages will be apparent from the following more particular description of the embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the embodiments. 
           [0009]      FIG. 1  illustrates an upper, front perspective view of an embodiment of a low-clearance, rack-mounting system. 
           [0010]      FIG. 2A  through  FIG. 2C  respectively illustrate a top, front and side views of an embodiment of a rack-mountable shelf 
           [0011]      FIG. 3  illustrates an upper, front perspective view of an embodiment of a low-clearance, rack-mounting system. 
           [0012]      FIG. 4  illustrates a front view of an example of a device mountable by a low-clearance, rack-mounting system. 
           [0013]      FIG. 5  illustrates cantilever mounting of an example of a device within an embodiment of a device carrier that is, in turn, mountable by an embodiment of a low-clearance, rack-mounting system. 
           [0014]      FIG. 6  illustrates an example of a device secured to an embodiment of a device carrier that is, in turn, mountable by a low-clearance, rack-mounting system. 
           [0015]      FIG. 7A  illustrates cantilever mounting of an example of a device within an embodiment of a device carrier 
           [0016]      FIG. 7B  illustrates insertion of the mounted device shown in  FIG. 7A  into an embodiment of a low-clearance, rack-mounting system. 
           [0017]      FIG. 8  illustrates an upper perspective view of two example devices mounted within a low-clearance, rack-mounting system. 
           [0018]      FIG. 9  illustrates a lower perspective view of a portion of the two example devices mounted within the low-clearance, rack-mounting system illustrated in  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    Unfortunately, in at least some instances, devices have an overall height that fails to meet acceptable clearance requirements when rack mounted with a separate shelf or tray. That is, the overall height of such devices is an integer number of standard rack units (e.g.,  1 U,  2 U, . . . ), or slightly less than an integer number of standard rack units, but not less than acceptable clearance requirements (e.g., 1/32-inch (0.031″)) to prevent binding or interference when rack mounted on a shelf or tray. The device is supported by a shelf, for example, sitting on a lower supporting member of the shelf, such tat a thickness of the lower supporting member adds to the overall height occupied by the shelf-mounted device. One such unit is the TACLANE-MICRO KG-175D encryption device, available from General Dynamics, C4 Systems of Scottsdale, Ariz. Beneficially, the low-clearance, rack-mounting systems described herein accommodate rack mounting of such devices, while complying with standard rack unit measurements and without wasting valuable rack space. In at least some embodiments, such rack mounting can be accomplished without the need for tools. 
         [0020]      FIG. 1  illustrates an upper, front perspective view of an embodiment of a low-clearance, rack-mounting system  100 . The system includes a rack-mountable shelf  102  including a lower, horizontal or tray support surface  104  extending substantially between left and right vertical side walls  106   a,    106   b  (generally  106 ). The rack-mountable shelf  102  accommodates one or more device carrier chassis  108   a,    108   b  (generally  108 ), that can be inserted from a front surface  110  of the shelf, as shown. The example system is configured to accommodate two modules (e.g., electronic modules), one within each of the device carrier chasses  108 . Other configurations can accommodate one device or more than two devices in a similar fashion. 
         [0021]    In at least some embodiments, the rack-mountable shelf  102  includes one or more support brackets  112   a,    112   b  (generally  112 ). The support brackets  112  allow for fastening of a rear portion of the rack-mountable shelf  102  to an equipment rack support member (not shown), thus providing additional support. In the example embodiment, left and right support brackets  112  are fastened to the rack-mountable shelf  102 , extending rearward to engage an equipment rack support member, such as left and right rear vertical frame members (not shown). Such support brackets  112  can be adjustable, as shown, to accommodate mounting within equipment racks of different depths. For example, the support brackets  112  can be attached to respective vertical side walls  106  through a multi-hole, and/or slotted hole-fastener arrangement, allowing for a travel distance Ad along a directed extending away from a front surface  110  of the shelf  102 , thereby accommodating rear-supported mounting within equipment racks of various depths. In some embodiments, the support brackets  112  all for secure mounting of the shelf  102  within equipment racks having depths of, for example, 24 inches and 36 inches. 
         [0022]      FIG. 2A  through  FIG. 2C  respectively illustrate a top, front and side views of the rack-mounting system  100 . In at least some embodiments, the lower tray support surface  104  includes at least one cutout to accommodate a portion of a device, when mounted therein. The lower tray or shelf support  104  of the example embodiment includes two such cutouts  120   a ,  120   b  (generally  120 ) to accommodate two electronic devices (not shown). The cutouts  120  are dimensioned such that at least a portion of the shelf support  104  remains to serve as a lower device support. In the example embodiment, two such support surfaces  119   a ′,  119   a ″ are provided for the first cutout  120   a  and two similar support surfaces  119   b ′,  119   b ″ are provided for the second cutout  120   b.  In the example embodiment, these surfaces, collectively  119 , are located adjacent to one or more edges of the cutouts  120 . In at least some embodiments, the device support surfaces  119  are relatively smooth and free of interference to accommodate slideable insertion and removal of devices from a front surface  110  of the rack-mountable shelf  102 . 
         [0023]      FIG. 3  illustrates an upper, front perspective view of the low-clearance, rack-mounting system  100 . Two empty device carrier chasses  108   a,    108   b  are shown mounted within the rack-mountable shelf  102 . Each of the carrier chassis  108  includes mounting flanges  122   a ′,  122   a ″,  122   b ′,  122   b ″ (generally  122 ) configured for securing the carrier chassis  108  to the front panel  110  of the rack-mountable tray  102 . Bottom edges  130 ′,  130 ″ of left and right vertical side walls of each device carrier chassis  108  rest along a top side of the horizontal surface  104  of the rack-mountable shelf  102 . A vertical height ‘H’ of the low-clearance, rack-mounting system is illustrated. For example, the height H is  1 U, including appropriate clearance (i.e., H=1.75 inches— 1/32 inch, or approximately 1.71 inches). 
         [0024]      FIG. 4  illustrates a front view of an example of a standard-rack-height device  200  mountable by the low-clearance, rack-mounting system  100 . In an illustrative example, the overall height of the device is also a standard  1 U rack height, including some clearance (e.g., H=1.719 inches). In the illustrative example, the device  200  includes standoffs or feet  204  as in the TACLANE-MICRO KG-175D encryption device, presenting an additional challenge for shelf-mounting in a low-clearance application. Normally, the feet  204  would extend for some height below a bottom surface  203  of the device  200 , such that the overall height H of the device, with feet would be greater than the height of a front panel  210  of the device  200 . Beneficially, in the present rack mounting system  100 , the cutouts  120  allow such feet  204  to extend below the horizontal surface of the shelf  104 . 
         [0025]      FIG. 5  illustrates a mounting process as used in the illustrative example of a standard-rack-height device  200  within the device carrier  108 , which is mountable within an equipment rack by the low-clearance, rack-mounting system  100 . The device carrier, or chassis  108  includes an open frame  140  having a lower horizontal support, or bar  142 . The length of the bar  142  is sufficient to accommodate a width of a device  200 , typically providing some clearance to facilitate mounting/dismounting of the device  200 . The carrier chassis  108  also includes opposing left and right vertical side walls  144 ′,  144 ″ (generally  144 ). Forward portions of each of the left and right side  144  walls are fixedly attached at either end of the lower horizontal support bar  142 . Also attached at forward portions of each of the side walls  144  are respective flanges  122 ′,  122 ″ configured to abut adjacent surfaces of a front panel  110  (e.g.,  FIG. 1 ) of the rack-mountable tray  102 . In some embodiments, one or more of the side walls  144 , horizontal support bar  142  and mounting flanges  122  are formed as a single unit, for example being bent or otherwise formed from a single piece of sheet metal. Alternatively or in addition, one or more components of the chassis  108 , including the entire chassis itself  108 , can be molded, or die cast. The chassis  108  can be made from similar or identical material as used for the rack-mountable tray  102 . Such materials include steel. Other materials can be used, provided that they have substantial rigidity and strength to support a device  200  without otherwise deforming or breaking Such materials can include polymer based materials, such as plastics, and resin based materials, such as reinforced fiberglass, and more generally, composites, including fibers within a solid matrix, such as a resin. 
         [0026]    The carrier chassis  108  also includes at least one device-mounting strap. The example embodiment includes two such straps: a forward mounting strap  150 ′ and a rear mounting strap  150 ″. The device-mounting straps  150 ′,  150 ″ (generally  150 ) extend between top edges  132 ′,  132 ″ (generally  132 ) of the left and right side walls  144 , being securely attached at either end to the adjacent wall  144 . Preferably, the device-mounting straps  150  are configured to engage a feature of the mounted device  200  to prevent forward and or rearward movement of the device  200  when mounted within the chassis  108 . 
         [0027]    In the example embodiment, a top surface  202  of the device  200  includes flutes or grooves  204 . Such features  204  can be included in the top surface  202  of the device  200  for the particular purpose of engaging the device-mounting straps  150 , or can be features  204  of opportunity as may be provided by a heat sink. In the example embodiment, each of the device-mounting straps  150  is sized, shaped and positioned to fit within a respective flute or groove  204 , preferably without extending above a maximum height H of the device, such that the device-mounting straps  150  do not interfere with or bind when the chassis  108  and a mounted device  200  is slid into or removed from an opening in the front surface  110  of the shelf  102 . In mounting, a front portion  206  of the device  200  is slid forward between the left and right side walls  144 , until the front portion  206  is over the horizontal support bar  142  and substantially aligned with the left and right front mounting flanges  122 . A rear portion  208  of the device  200  is initially positioned during mounting below rearward ends of the left and right side arms  144 . The device can be approximately pivoted about the horizontal support bar  142  in a cantilever fashion, such that the rear portion  208  is rotated from a lower position, below bottom edges  130  of each sidewall  144 , upward, toward the rear device-mounting strap  150 ″. Such pivoting continues until at least the rear device-mounting strap  150 ″ engages an adjacent flute or groove  204  on the device  200 . 
         [0028]      FIG. 6  illustrates an example of a standard-rack-height device  200  secured to an embodiment of a device carrier  108  mountable by a low-clearance, rack-mounting system. As illustrated each of the front and rear mounting straps  150 ′,  150 ″ is positioned within an adjacent groove  204 ′,  204 ″. When mounted in the example chassis  108 , the front portion  206  of the device  200  rests upon the horizontal support bar  142 . A front surface  210  of the device  200  can be substantially in the same plane as the support flanges  122 , that abut a front surface  110  of the mounting shelf  102 . In some embodiments, the device  200  can be accommodated or otherwise mounted in the chassis  108  such that the front surface  210  protrudes from or is recessed with respect to the front surface  110 . 
         [0029]      FIG. 7  illustrates cantilever mounting of an example of a standard-rack-height device  200  within an embodiment of a device carrier  108  mountable by a low-clearance, rack-mounting system  100 , and insertion of the chassis-mounted device  200  into a low-clearance, rack-mounting shelf  102 . Once the device  200  is secured within the device carrier  108 , the device  200  and carrier  108  combination can be inserted into a respective opening  111  in the front panel  110  of the rack-mountable shelf  102 . The device  200  and carrier  108  are inserted until rear-racing surfaces of the left and right front mounting flanges  122  of the carrier  108  abut front surfaces of the front panel  110  of the rack-mountable shelf  102 . Fasteners, such as the thumbscrews  113  shown, can be provided to secure the carrier mounted device  200  with respect to the rack-mountable shelf  102 . The rack-mountable shelf  102 , in turn, can be inserted and secured to a standard equipment rack (not shown). Beneficially, insertion of the carrier-mounted device  200  can be accomplished before or after the rack-mountable shelf  102  has been secured within an equipment rack. 
         [0030]    Thus, in mounting a device  200  in an example embodiment of a rack-mounting system  100 , the device  200  is slid into the carrier  108  as illustrated in  FIG. 7A . The front of the device is positioned to be flush with a front edge of the carrier  108 . For example, the front panel  210  of the device, is substantially in the same plane as the front mounting flanges  122 . The carrier  108  containing the mounted device  200  can be slid into an opening  111  in a front panel  110  of the rack-mountable shelf  102 . The carrier  108  can be fastened to the shelf  102 , for example, by securing the front flanges  122  to abutting portions of the front panel  110  of the shelf  102 . Fasteners can be used to provide a securable attachment of the carrier  108  to the shelf  102 . In at least some embodiments, the fasteners include thumb-screws, such that the entire mounting procedure of the device  200  to the carrier  108  and the carrier  108  to the shelf  102  can be accomplished without the need for tools. 
         [0031]      FIG. 8  illustrates an upper perspective view of two example standard-rack-height devices  200   a,    200   b  flush mounted within a low-clearance, rack-mounting system  100 . Also illustrated are ancillary equipment, such as power supplies  260  that can be positioned on, and in some instances secured to, the rack-mountable shelf  102 . 
         [0032]      FIG. 9  illustrates a lower perspective view of a portion of the two example standard-rack-height devices  202   a,    202   b  mounted within the low-clearance, rack-mounting system  100  illustrated in  FIG. 8 . In the illustrative embodiments, the cutout  120   a  is sized to accommodate the device standoffs or feet  204 , allowing the feet  204  to extend below a top surface of the horizontal mounting shelf  104 . In the illustrative embodiment, at least a portion of a lower surface  203  of the device  200  overlaps an adjacent portion of the horizontal mounting shelf  104 . Such overlap  119   a ′ may extend along one or more edges of the tray cutout  120   a . Advantageously, such overlap  119   a ′ prevents vertical movement and/or rotation of the device  200 , thereby keeping the device  200  engaged with the one or more device mounting straps  150  (e.g.,  FIG. 6 ). 
         [0033]    In at least some embodiments, a forward portion  121   a  of the cutout  120   a  is dimensioned to accommodate the horizontal support  142  of the device carrier  108  to efficiently conserve overall height. Namely, the depth of the horizontal support  142  does not add to an overall height of a chassis mounted device  200 , as the height of the horizontal support  142  is allowed to extend below the top surface of the shelf  104 , as accommodated by the forward portion  121   a  of the cutout  120   a.  Also shown is a tapered portion  123   a ″ extending between the forward portion  121   a  of the cutout  120   a  and the rest of the cutout  120   a.  The taper  123   a ″ can be configured to guide device standoffs or feet into the tray cutout. 
         [0034]    One skilled in the art will realize the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting of the invention described herein. Scope of the invention is thus indicated by the appended claims, rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.