Abstract:
An earthquake resistant frame structure which is shippable in a fully populated condition has abase member, a plurality of support members extending from the base member, a top portion disposed over the ends of the support members, a extension member disposed over the top portion, side stiffeners positioned perpendicularly between the support members, and a tie down assembly system positioned between the base member and a flooring surface. The extension member has a platform section and at least two legs depending substantially perpendicularly therefrom that slidingly engage the support members. The two legs have slots therethrough configured to receive fasteners that, when secured to support members, secure and maintain the extension member in position. First and second panels protrude laterally from the frame structure to form an extension area, from which a bracket hingedly depends. A variety of pin arrangements are used to prevent the removal of the bracket from the hinge. The tie down system includes a floor plate positionable between the frame structure and the flooring surface, a fastener extending through the frame structure, through the floor plate, and into the flooring surface, a leveling element positioned between the floor plate and the flooring surface to level the frame structure, and insulators positioned between the fastener and the leveling element to attenuate vibration.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is divisional application of U.S. Ser. No. 09/547,775 filed Apr. 12, 2000, the disclosures of which are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a frame structure for housing electronic equipment, and, more particularly, to an earthquake resistant support frame for electronic equipment. 
     Electronic equipment, which may be mainframe computers, information technology equipment, telecommunications circuitry, air traffic control systems, or similar equipment, generally comprises sophisticated and delicate components assembled in a manner such that the electrical and mechanical connections therebetween are delicate and subject to interruption of the continuous flow of electronic data as a result of the loss of the connection. Continuous flow of electronic data through the electronic equipment is often of critical importance to a system and can lead to detrimental results in the event of an interruption of that flow. Frame retention systems that form an integral part of electronic equipment systems are designed to ensure the continuous flow of data and are utilized to curtail the likelihood of damage to electronic equipment that may result from either man-made or natural vibratory motion. 
     The vibratory forces generated by an earthquake or other seismic shock activity can often be of a sufficient magnitude to break the physical connections between the electrical and mechanical components. Various degrees of protection can be afforded to electronic equipment in order to prevent or limit the amount of damage that can potentially result from seismic activity. Frame retention systems in the form of aseismic support structures and methods of securement have been developed and are used within the electronics industry to compensate for the vibrations resulting from this seismic activity. 
     In order to prevent the interruption of the flow of data, the electronic equipment should be installed and secured in such a manner so as to withstand or resist the vibratory forces that may detrimentally affect the connections. It is a normal practice within the electronic industry, as known from the prior art, to contain the electronic equipment within a frame-like structure and secure the structure to a base, which is usually fixedly secured to the floor. The frame-like structure, as well as the base, is usually modular; however, the sections involved are typically of massive size and weight to accommodate the large vibratory forces generated by earthquakes. 
     While this method is straightforward and effective, the structures involved, viz., the frame itself as well as the base, are often costly to manufacture and do not lend themselves to being conveniently moved to the site of installation. Moreover, this method fails to address the problem of relocation of the equipment. 
     Another method of preventing interruption of data flow is through the use of less rigid structures that allow the frame to flexibly shift under the vibratory forces generated by earthquakes. In particular, one approach is to mount casters on an underside of the frame to allow the frame free access to movement over a surface. Normally, the casters can be braked such that the frame is prevented from movement during normal use. If vibratory forces of a sufficient and predetermined magnitude are sensed and experienced by the frame, the caster braking system can be released so that the movement of the frame absorbs the energy of the earthquake. The use of casters as support members, however, contributes to the instability of the frame as vibratory forces are experienced. In the event of a significant earthquake, the vibrations generated may be sufficient to cause the frame to tip over. 
     SUMMARY OF THE INVENTION 
     An electronic equipment frame having an integrated earthquake restraint system is needed that is of a manageable size and weight. The inventive frame is a flexible structure being adjustable vertically with respect to a level plane of a flooring surface to accommodate electronic equipment of heights variable between 36 units EIA and 42 units EIA loaded at up to 35 pounds per unit EIA. The structure may be modified to accommodate electronic equipment of heights that are greater than 42 units EIA. An optional brace, when properly secured, renders the frame capable of withstanding a higher NEBS rating and, in one embodiment of the invention, an NEBS GRE-63 Zone  4  earthquake rating. Without the brace, the frame is capable of withstanding NEBS GRE Zone  1  and Zone  2  earthquake ratings. Furthermore, the inventive frame is mountable to either a raised or a non-raised flooring surface using a leveler and tie down system that ensures a uniform height over a level area of the frame, induces a pre-stress load over the flooring surface, and provides adequate insulation and vibrational attenuation to the electronic components. The floor mounting plate is easily accessible to allow the frame to be easily moved. 
     An earthquake resistant frame structure has a base member, a plurality of support members extending normally from the base member, a top portion disposed over the end portions of the support members, a extension member disposed over the top portion, side stiffeners positioned perpendicularly between the support members, and a tie down assembly system positioned between the base member and a flooring surface. The extension member has a platform section and at least two legs depending substantially perpendicularly therefrom that slidingly engage the support members. The two legs have slots or holes therethrough configured to receive fasteners that, when secured to the support members, secure and maintain the extension member in position. 
     First and second panels protrude laterally from the frame structure to form an extension area, from which a bracket hingedly depends. The bracket, which is generally triangular in shape, is removably attached to the first panel. Removal of the bracket can be prevented by the installation of a locking hinge assembly. The locking hinge assembly is an L-shaped hinge having a first end pivotally received on the first panel and secured thereto. A second end of the L-shaped hinge is fixedly attached to the bracket. A variety of pin arrangements are used to prevent the removal of the bracket from the L-shaped hinge. The edge of the bracket that is distal from the hinged edge is securable to the second panel using a plate and bolt assembly. 
     The extension member includes a platform section and a plurality of legs depending from the platform section. Each leg includes openings therein that are engageble with corresponding openings in the frame structure. The extension member is securable to the frame structure by the insertion of fasteners extending through the openings in the legs and into the corresponding openings in the frame structure. Typically, the fasteners are bolts that are received through the openings in the legs and are threaded into the corresponding openings in the frame structure. 
     The tie down system includes at least one floor plate positionable between the frame structure and the flooring surface. A fastener extends through the frame structure, through the floor plate, and into the flooring surface. A leveling element is positioned between the floor plate and the flooring surface to level the frame structure, and insulators are positioned between the fastener and the leveling element to damp vibration. 
     The above-described inventive frame also enables an electronic system to be shipped fully populated. Casters are rollably fixed to the bottom of the frame, thereby allowing the frame to be easily rolled during shipment onto and off of a transport device and rolled to its final delivery location. Installation of the frame using the leveling elements, which are threaded such that the frame can be raised and lowered by articulating the leveling elements, allows the casters to remain secured to the bottom of the frame after the frame is mounted to the floor plates. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is perspective view of the flexible frame tie down retention system, or frame, of the present invention. 
     FIG. 2 is a cross sectional view of a support member of the frame, of the present invention. 
     FIG. 3 is a cross sectional view of two side stiffeners of the frame, of the present invention. 
     FIG. 4 is an exploded perspective view of the frame, of the present invention, showing the top portion and the extension member, of the present invention. 
     FIG. 5 is a side elevation view of the frame, of the present invention, mounted on rollable casters. 
     FIG. 6 is a perspective view of the frame, of the present invention, showing a triangular bracket of the frame, of the present invention, in an open position. 
     FIG. 7 is a front elevation view of the triangular bracket of the frame, of the present invention. 
     FIGS.  8 A through FIGS. 8E are perspective views of various embodiments of a hinge locking system of the triangular bracket of the frame, of the present invention. 
     FIG. 9 is an exploded perspective view of a tie down assembly, of the present invention, integrated with a base member of the frame, of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, the inventive integrated flexible frame tie down retention system for raised and non-raised floor applications is shown generally at  10  and is hereinafter referred to as “frame  10 ”. Frame  10  is an open box-like structure and comprises a plurality of support members  12  arranged in a parallel configuration to form the edges of frame  10 . The length of one side of the box-like structure is typically less than adjacent sides of the box-like structure, thus giving the box-like structure a substantially rectangular cross sectional shape. In a preferred embodiment, frame  10  is oriented such that support members  12  are positioned vertically with respect to a level plane of a flooring surface (not shown). In FIG. 2, a cross sectional view of support member  12  illustrates the configuration of each individual wall element of support member  12 . While only one support member is referenced below, additional support members are similarly configured. Support member  12  comprises four walls  14 ,  16 ,  18 ,  20 , each being individually shaped and assembled to impart optimum strength to frame  10 . In a preferred embodiment, walls  14 ,  16 ,  18 ,  20  are fastened together preferably by welding or riveting. 
     First wall, shown generally at  14 , comprises an L-shaped member having a shorter leg  22  and a longer leg  24 . The side of longer leg  24  that is opposite the direction of projection of shorter leg  22  forms an exterior surface of support member  12  that faces away from frame  10 . A portion of longer leg  24  extends beyond the point at which second wall  16  engages first wall  14  to form a flange  25 . 
     Second wall, shown generally at  16 , comprises a flat member  26  having a ridge  28  disposed therein and an edge that is bent to form a lip  30 . Ridge  28  is of a semi-circular cross section and extends along a lengthwise plane of flat member  26 . Lip  30  likewise extends along the same lengthwise plane of flat member  26  parallel to ridge  28  and is bent in the same direction that ridge  28  projects out of the plane of flat member  26 . Second wall  16  is fixedly connected to shorter leg  22  of first wall  14  such that second wall  16  intimately engages the surface of shorter leg  22  of first wall  14  that faces away from longer leg  24  of first wall  14 . The side of flat member  26  that is opposite of the direction in which ridge  28  projects forms another exterior surface of support member  12  that faces away from frame  10 . 
     Third wall, shown generally at  18 , comprises two flat planar members  32 ,  34  connected such that the plane of first flat planar member  32  is offset from the plane of second flat planar member  34 . A lip  36  is formed along the outer edge of first flat planar member  32 . The opposing edge of third wall  18 , which is the outer edge of second flat planar member  34 , is also bent to form a lip  38  positioned to be ninety degrees relative to the plane of second flat planar member  34 . Third wall  18  is fixedly connected to first wall  14  such that third wall  18  is parallel to second wall  16  and such that a surface of lip  38  intimately engages the surface of longer leg  24  of first wall  14  that faces shorter leg  22  of first wall  14 . 
     Fourth wall, shown generally at  20 , comprises a flat planar member positioned between second wall  16  and third wall  18 . Fourth wall  20  is perpendicularly situated to second wall  16  and third wall  18  and is parallel to first wall  14 . Lip  30  of second wall  16  and lip  36  of third wall  18  serve to hold fourth wall  20  in place therebetween. 
     Referring back to FIG. 1, side stiffeners, shown generally at  40 , are positioned perpendicularly between and fixedly secured to adjacently positioned support members  12  forming the longer side of the box-like structure of frame  10 . Side stiffeners  40  are likewise positioned on the opposing longer sides of frame  10 . Side stiffeners  40  are substantially L-shaped members having a plurality of openings  42  disposed throughout the surfaces there of in order to facilitate the circulation of air around frame  10  and electronic equipment (not shown) housed within frame  10 . Each side stiffener  40  is positioned such that the orientation thereof is varied with respect to adjacent side stiffeners  40 . This variation in orientation serves to impart added strength to frame  10  by reinforcing support members  12 . 
     Referring to FIG. 3, two side stiffeners  40  are illustrated in cross sectional view, as they would be positioned adjacently between support members  12 . The outer edges of L-shaped members are bent at ninety-degree angles. As previously stated, side stiffeners  40  shown are oriented differently between support members  12  to impart added strength to frame  10 . 
     Referring to FIGS. 1 and 4, a extension member is shown generally at  44 . Extension member  44  is movably positioned on the ends of support members  12  over a top portion  43  fixed to frame  10 . Extension member  44  comprises a platform section  48 , which is a flat planar surface horizontal with the level plane of the flooring surface when frame  10  is oriented in an upright position, and at least two legs  45  depending perpendicularly from the edges of platform section  48  to fit over opposing sides of frame  10 . Extension member  44  is slidably positioned over the ends of support members  12  and is secured into place by fasteners such as bolts (not shown) extending through elongated slots  47  or holes (not shown) in legs  45  and tightening the bolts. Loosening the bolts allows the height of frame  10  to be adjusted by sliding extension member  44  vertically so that slots  47  are traversed by the loosened bolts. Retightening the bolts resecures extension member  44  in position. When positioned in a vertical orientation with respect to the flooring surface, the height of frame  10  is variable between 36 units EIA and 42 units EIA or higher. Numerous vent holes  50  perforate top portion and extension member  44  to allow air to circulate thereby causing heat to dissipate from frame  10  when frame  10  is operational with electronic equipment. The securement of height-extending cover  44  to the upper ends of all support members strengthens and improves the structural integrity of frame  10 . 
     Referring to FIGS. 1 and 4, a base member is shown generally at  46 . Base member  46  is a flat planar member adapted to intimately engage the level plane of the flooring surface and provide a surface upon which support members  12  rest. Casters, shown at  53  in FIG. 5, are well known in the art and are securable to the flooring surface side of base member  46  in order to facilitate the rolling of frame  10 . Casters installed on the underside of frame  10  allow frame  10  to be fully assembled and populated at one site and shipped on a transport device  55  such as a truck or train, etc. to an installation site without being loaded onto a pallet (not shown). Once the populated frame  10  reaches its destination, frame  10  can be anchored to the flooring surface, as described below, with casters  53  left in place. 
     Base member  46  also provides a means to which tie down assembly systems (described below with reference to FIG. 9) can be fixed to securely anchor frame  10  to the flooring surface. The securement of base member  46  to the lower ends of support members  12  further strengthens and improves the structural integrity of frame  10  in a manner similar to that accomplished by extension member  44 . 
     Also illustrated in FIGS. 1,  4 , and  5  is an extension area, shown generally at  51 . When frame  10  is vertically oriented relative to the flooring surface, extension area  51  is disposed on a shorter edge of frame  10 . Extension area  51  comprises a first panel  54  and a second panel  56 , each extending from two support members  12  that define the shorter edge of frame  10 . Panels  54 ,  56  are secured in a parallel planar relationship with each other and extend between and are attached to extension member  44  and base member  46 . Cable holes  58  are formed in panels  54 ,  56  to enable cables (not shown) to be snaked between pluralities of frames  10  positioned side by side. Belt loop holes  59  are also formed in panels  54 ,  56 , which can be used to secure the cables to panels  54 ,  56  using a belt (not shown) or a similar means of securement. 
     FIG. 1 also illustrates a triangular bracket, shown generally at  60 . Triangular bracket  60  is hingeably connected to first panel  54  and can swing outward and away from frame  10 , as shown in FIG. 6, to allow access to electronic equipment mounted within frame  10 . A hinged door  61  may be positioned over triangular bracket  60 . The addition of triangular bracket  60  on frame  10  converts frame  10  from a structure able to withstand vibratory forces comparable to those of NEBS GRE-63 Zone  1  and Zone  2  earthquakes to a structure capable of withstanding more severe environments such as those comparable to NEBS GRE-63 Zone  4  earthquakes. Triangular bracket  60  is configured to extend between first panel  54  and second panel  56  and is removably connected to frame  10  in such a manner so as to not inhibit the installation, access to, or removal of the electronic equipment in frame  10 . Locking hinge assemblies, shown generally at  62 , on first panel  54  and a conventional plate and bolt assembly, shown generally at  64 , on second panel  56  allow triangular bracket  60  to be secured in place between first panel  54  and second panel  56 . 
     Referring now to FIG. 7, triangular bracket  60  is shown in greater detail. Triangular bracket  60  comprises a support element  66 , which is hingeably attached to an upright surface of first panel  54  and is removably attached thereto using locking hinge assemblies  62  (shown below in greater detail with reference to FIGS.  8 A through  8 E). Retaining elements  68 , of which there are usually two, as shown in the Figures, depend angularly from support element  66  in the same direction and converge on a plate  70  of plate and bolt assembly  64 . Support element  66  and retaining elements  68  are dimensioned such that when support element  66  is properly attached to first panel  64 , plate  70  of plate and bolt assembly  64  is securable to second panel  56  at a point intermediate the upper and lower ends of second panel  56 . 
     Referring to FIGS. 8A through 8E, various embodiments of locking hinge assemblies  62  may be used to prevent triangular bracket  60  from being removed or from swinging open during a period when increased vibratory forces act on frame  10 . In each embodiment, a hinge  72 , which is a substantially L-shaped element, is pivotally received on a vertically-projecting rod (not shown) of a mount plate  74  and is securely fixed to support element  66 . Mount plate  74  is secured to first panel  54  using conventional methods. In FIG. 8A, hinge  72  is prevented from being lifted off the vertically projecting rod and being removed from mount plate  74  by a locking bracket  76 , which, when fixed to first panel  54  as shown and when triangular bracket  60  is in a closed position, prevents the movement of hinge  72  in the direction of an arrow  78 . In a similar manner shown in FIG. 8B, hinge  72  is prevented from removal from mount plate  74  by a wide washer  80  secured to first panel  54  using a bolt. In FIG. 8C, after hinge  72  is mounted on the vertically-projecting rod, a pin  82  perpendicularly fixed to support element  66  protrudes laterally into an opening (not shown) on a side of mount plate  74  opposing the side from which the vertically-projecting rod extends. In such a configuration, mount plate  74  is entrapped between hinge  72  and pin  82 , and triangular bracket  60  cannot be removed without first being swung open to allow pin  82  to be disengaged from the opening. In FIG. 8D, pin  82  is integrally formed with hinge  72  and functions similar to the embodiment illustrated in FIG.  8 C. In FIG. 8E, pin  82  protrudes normally from the flat plane of hinge  72  that engages first panel  54 . Pin  82  extends from hinge  72  and into a hole (not shown) in first panel  54  and functions similar to the embodiments of FIGS. 8C and 8D to prevent removal of triangular bracket  60  without first swinging triangular bracket  60  open. 
     Referring now to FIG. 9, tie down assemblies are shown generally at  86  at two adjacent corners of frame  10 . Tie down assemblies  86  allow for the secure retention of frame  10  to the flooring surface in both raised and non-raised floor applications. The configuration of tie down assemblies  86  are such that the installation hardware is easily accessible for removal or maintenance. The spacing of frame  10  from the flooring surface using a floor plate (shown below), furthermore, provides electrical and thermal isolation of frame  10  and electronic equipment. 
     Tie down assemblies  86  are structurally integrated into the lower part of frame  10  to secure frame  10  to the flooring surface and to provide greater strength to frame  10  while maintaining the simplicity of the overall design. Tie down assembly  86  extends between two adjacent corners of base member  46  of frame  10  and comprises a floor plate  88 , leveling elements  90 , bolts  92 , first insulators  94 , and second insulators  96 . Floor plate  88  has threaded holes  98  drilled therein for threadedly receiving bolts  92  is are preferably fabricated from a material that is electrically non-conductive. Floor plate  88  itself is installed directly on the flooring surface. To secure frame  10  to floor plate  88  using tie down assemblies  86 , the shaft portions of bolts  92  are inserted through a plurality of washers  100  and first insulators  94  and through holes  102  inbase member  46  from the frame side of base member  46 . First insulators  94  are retained on the shaft portions of bolts  92  against the head portions of bolts  92 . Second insulators  96  are inserted into leveling elements  90 , which are then received on the shaft portions of bolts  92 , that protrude through the floor plate side of base member  46 . Leveling elements  90 , when properly received on the shaft portions of bolts  92  extend through holes  102  inbase member  96  to receive first insulators  94  therein. When first insulators  94  and second insulators  96  are properly received within leveling elements  90 , bolts  92  protrude from leveling elements  90  and are threadedly received in threaded holes  98  drilled in floor plate  88 . Washers  104  may be utilized in the assembly process to properly space bolts  92  from base member  46  and floor plate  88 . A second tie down assembly  86  with a second floor plate  88  and hardware identical to the above tie down assembly  86  extends between other adjacent corners of base member  46  of frame  10  to further secure frame  10  to the flooring surface. 
     While the invention has been described with reference to specific embodiments thereof, it is intended that all matter contained in the above description and shown in the accompanying drawings be interpreted as illustrative and not limiting in nature. Various modifications of the disclosed embodiments, as well as other embodiments of the invention, will be apparent to those skilled in the art upon reference to this description, or may be made without departing from the spirit and scope of the invention as defined in the appended claims.