Abstract:
Apparatus and method for shielding interference, comprising a clamping bracket filled with a filling member, designed to accommodate cables of varying sizes, allow for easy substitution of one cable for another and provide a means to integrate the faraday cage between multiple chassis/enclosures.

Description:
FIELD OF INVENTION  
         [0001]    This invention relates to shielding interference. More specifically, this invention relates to shielding electromagnetic interference (“EMI”) and radio frequency interference (“RFI”) in electronic devices.  
         BACKGROUND OF THE INVENTION  
         [0002]    EMI, especially RFI (EMI on the radio band), is a potential problem whenever more than one piece of electronic equipment coexist in the same environment. Computer hardware emits electromagnetic waves at frequencies throughout the spectrum. If this EMI is not controlled, a computer or network apparatus can interfere with the use of other devices that transmit or receive electromagnetic radiation, including AM and FM radios, televisions, cellular telephones and other personal communication devices, and medical devices such as pacemakers, hearing aids, and defibrillators. Additionally, within a large computer structure, the individual components can function sub-optimally if EMI is not properly curtailed. For these and other reasons, electromagnetic emissions are regulated, within the United States, by the Federal Communications Commission (FCC). Compliance with FCC rules for acceptable level and frequency of electromagnetic interference is required for any product sold in the United States, and is therefore extremely important to manufacturers and users of devices that emit electromagnetic radiation.  
           [0003]    Within the environment of an electronic computer or cabinet, cables are used to transmit data and/or signals from one point to another. Cables can be used to transmit data from storage devices within the computer, from across the world via the Internet, or from anywhere in between. Cables can also be used to transmit signals of one kind or another to different parts of the electronic system, so that those parts can function appropriately.  
           [0004]    Problems with EMI can be minimized by ensuring that all equipment that emits electromagnetic radiation is effectively grounded. This is often done by shielding the conductive material in the cable from the external environment, by wrapping the cable with a shielding material. Shielded cable is known in the art. However, often, cable will need to be unshielded in places to function in the system, or when shielding to mask necessary EMI is prohibitive in terms of cost or space.  
           [0005]    In larger electronic cabinets, especially in computer and data network equipment, a large number of data and signal cables enter the system through different chassis. These cables have a multitude of sizes, shapes, shielding, and purposes. Various chassis for cable entry into electronic cabinets are known in the art. However, many chassis known in the art that reduce EMI subject the cables to deformation in the form of compression, which can hinder performance of the cable&#39;s function.  
           [0006]    Additionally, many prior art solutions cannot accommodate cables having various thicknesses, because the shielding material used has a specific opening for a cable. The inability of different types of cables, each having a different thickness, to enter or exit a system, inhibits system growth.  
           [0007]    Many cable chassis in the prior art have fixed parts. This makes these chassis difficult to assemble, requiring skilled labor for such assembly, and fixturing. Additionally, these fixed parts limit the choices that consumers of these chassis can make with respect to the type of cable they use.  
           [0008]    Chassis known in the art do not permit interconnection with one another. Known chassis cannot adequately function as sub-chassis in a larger structure, because the shielded faraday cage is not maintained with each of the sub-chassis. In a large component of a larger system, a single cable may need to enter through one sub-chassis, and exit through another. In prior art systems, such a cable would not be properly grounded, and EMI would result. In other systems, upgrade ability is prohibitively expensive, making a decision to change cable type prohibitively expensive. The inability to link chassis to each other while maintaining a shielded faraday cage severely limits the expandability of electronic cabinet setups.  
         SUMMARY OF THE INVENTION  
         [0009]    The foregoing need has been met, to a great extent, by the present invention wherein one aspect, an apparatus capable of reducing interference from a cable within an enclosure is disclosed. The apparatus contains a front panel with a first opening, and a first filling member, attached to the front panel. The filling member shields interference. In one embodiment of this aspect of the present invention, the apparatus contains a clamping bracket, positioned adjacent to the first opening. The clamping bracket has a second opening, which is positioned adjacent to the first opening. The cable is positioned through an opening of the first filling member.  
           [0010]    In another aspect of the present invention, a method of limiting interference into or out of an enclosure, which is caused by an opening, is disclosed. The method includes the step of placing a shielding material at the opening. If a shielded cable is passed through the opening, the cable is encased with a shielding material at the opening. The shielding material is grounded to the enclosure. In one embodiment of the present invention, the method further comprises providing a bracket to secure the shielding material at the opening, providing a front panel which is secured and grounded to the enclosure at the opening, with the bracket attached to the front panel, and the bracket secures a plurality of the shielding material.  
           [0011]    In another aspect of the present invention, an system for limiting interference in and out of an enclosure, wherein the interference leaks through an opening of the enclosure, is disclosed. The apparatus includes a means for shielding interference at the opening, and a means for grounding shielding material to the enclosure.  
           [0012]    In another aspect of the present invention, an apparatus is disclosed. The apparatus contains a cabinet that contains electrical components. The cabinet has a first opening located on a first outer portion, and a second opening located on a second outer portion. The apparatus also contains a first filling member, which shields interference, within the first opening and a second filling member, which shields interference, within the second opening.  
           [0013]    There has been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.  
           [0014]    In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purposes of description and should not be regarded as limiting.  
           [0015]    As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent construction insofar as they do not depart from the spirit and scope of the present invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a break apart view of a preferred embodiment of the present invention, illustrating the individual component parts.  
         [0017]    [0017]FIG. 2 is a perspective view of the present invention.  
         [0018]    [0018]FIG. 3 is a flow-chart of an alternate embodiment of the present invention.  
         [0019]    [0019]FIG. 4 is a top view of an implementation of the preferred embodiment of the present invention.  
         [0020]    [0020]FIG. 5 is a perspective view of the implementation of the preferred embodiment depicted in FIG. 4. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    Referring now to FIG. 1, an apparatus for shielding interference from a cable is shown, which is a preferred embodiment of the present invention. A front panel  10  is shown having a first opening  12 . An upper bracket  14 , a lower bracket  16 , and side brackets  18   a  and  18   b  make up the outside of the clamping bracket  20 . The inside of the clamping bracket  20  is made up of a plurality of angled members  22 . The angled members  22  are rectangular in shape, having three sides (not labeled), with the fourth side including an opening. The opening can be on any side of the rectangular structure of the member  22 . The angled member  22  does not contain any material within its rectangular structure, and thus there is a second opening  24  in each angled member  22 . When each of the angled members  22  are adjacent to each other, the sizes of the second openings  24 , together, are substantially equivalent to that of the first opening  12 . Thus, when the apparatus is assembled, as shown in FIG. 2, the second openings  24  overlays the first opening  12 .  
         [0022]    Within each second opening  24  is either a solid EMI/RFI shielding member  26 , or a modified EMI/RFI shielding member  28 , which is designed to allow a cable  30  to pass through the member  28 . The member  28  has a hole  32  that is specially designed to accommodate the thickness of the cable  30 . The hole  32  in each member  28  can be a different size, to accommodate a different type of cable, so long as the cable is still surrounded at the point of entry by the EMI shielding material to effectively shield EMI within the system. The shielding material can be any material that is used to ground cables or shield interference from them. The preferred embodiment uses a silicone elastomer, with nickel-coated graphite filler material, namely the Instrument Specialties ElectroSeal Conductive Elastomer EMI Shielding, Material Number  12  manufactured by Laird Technologies. However, any other material or materials known to act as an Electrically Conductive Elastomer can be used. Once all of the shielding members  26  and  28  are loaded into the openings  24 , the side brackets  18  are attached to the angled members  22 , by screws  34 . The screws  34  can be of any type of connector that is used to connect metal parts and is removable and replaceable. Next, the top bracket  14  and the bottom bracket  16  are attached. This entire structure is then attached to the front panel  10 , so that the angled members are lined up properly with the opening  12  in the front panel  10 . The cable  30  is then shielded from EMI as it enters the structure through the second opening  24  and the first opening  12 , because it is surrounded at the entry point by the shielding member  28 .  
         [0023]    The shielding member  28  can be designed, or adapted, so that when the cable  30  passes through the shielding member  28 , there is minimal gap between the cable  30  and the shielding member  28 . This is important to ensure that EMI shielding and grounding is maintained. When assembled, the structure appears as in FIG. 2, with any number of cables  30 , possibly of varying lengths and thicknesses, entering or exiting through the openings  24  surrounded by shielding members  28 . When the larger structure, which the present embodiment is a part, requires an update to the cabling, the screws  34  can be removed. The particular shielding member  28  holding the cable  30  that requires replacing can itself be replaced by another shielding member  28  that can accommodate the thickness of the new cable  30  without significant air space. This ensures that the EMI shielding is maintained. The screws are then replaced, reattaching all of the component parts, to create the embodiment seen in FIG. 2, but with different cable  30  installed. Because of the modular nature of the present invention, this can be accomplished without shutting down the apparatus, or otherwise interrupting its operation. The present invention enables users of the device to upgrade cables easily and efficiently.  
         [0024]    Referring now to FIG. 3, a method of limiting interference into and out of an enclosure is shown. The method can be used to limit interference in the enclosure caused by an opening in that enclosure. The method further ensures that the shielded faraday cage of the enclosure is maintained. The interference can be electromagnetic interference, radio frequency interference or any other interference caused by electric wires or cables. First, the step  36  of placing the shielding material at the opening is accomplished. The shielding material can be made from any material or combination of materials that act as an Electrically Conductive Elastomer. In the preferred embodiment, the shielding material is a silicone elastomer, with nickel-coated graphite filler material, namely the Instrument Specialties ElectroSeal Conductive Elastomer EMI Shielding, Material Number Twelve. In a preferred embodiment, the step  38  of providing a bracket is completed to ensure that the shielding material is secured to the enclosure at the opening. A panel is provided by another step  40 . The panel is attached and secured to the enclosure at the opening. This front panel can be omitted, and the invention can retain all of its benefits. However, in the preferred embodiment, the front panel is provided, among other functions, to simplify securing of the shielding material, within the bracket, to the shielded enclosure. The next step  42  then determines if a cable is passed through the opening  32 . If the answer is yes, then the step  44  of encasing the cable, at the opening, with the shielding material is completed. If a cable is not passed through the opening or if a cable is passed through the opening, the next step  46  in the process step  46  is to ground the shielding material to the enclosure.  
         [0025]    Referring now to FIG. 4, a plurality of clamping shielding apparatuses  48  are shown. In this embodiment of the present invention, the apparatuses  48  are the same as the apparatus depicted in detail in FIGS. 1 and 2. The apparatuses  48  are positioned in various places around the perimeter of an electronic cabinet system  50 . A plurality of cables  30  enter through one of the apparatuses  48 . The apparatus  48  contains a shielding member  28  (not shown in FIG. 4 or  5 ) that is designed to accommodate, either through special manufacture or through field adjustment, a opening having the exact thickness of the cable  30 . When installing the system depicted in FIGS. 4 and 5, if a shielding member  28  cannot appropriately surround a cable having the thickness of the cable  30  within the apparatus  48 , one can be cheaply purchased, and easily installed. The shielding material can be any material that is used to ground cables or shield interference from them. The preferred embodiment uses a silicone elastomer, with nickel-coated graphite filler material, namely the Instrument Specialties ElectroSeal Conductive Elastomer EMI Shielding, Material Number  12 . However, any other material or materials known to act as an Electrically Conductive Elastomer can be used. The field upgrade process is described above, during the discussion of FIGS. 1 and 2. Once the apparatus  48  is properly configured to accept a cable the size of the cable  30 , the cable then enters the cabinet  50  through the apparatus  48 . The cable  30  then exits the cabinet  50  through another apparatus  48 , which is also properly configured with shielding members  28  designed to accommodate, through adjustment or special manufacture, cables having the thickness of the cable  30 . Because the cable  30  enters the cabinet through a shielded member  28 , and exits through another shielded member  28 , the faraday cage is maintained within the cabinet  50 . Because the cabinet  50  is protected in this way, it can be used as a sub-chassis in a larger electronic system (not shown).  
         [0026]    A second cable  52  is also shown. The second cable  52  has a different thickness than the first cable  30 . Thus, it is shown that the present invention can accommodate cables having differing thicknesses, by simply having shielding members  28  designed to accommodate a cable with that particular thickness. If more cables having the thickness of cable  52  are later needed, either to replace the cable  30  or in addition to the existing cables  30  and  52 , the filling member  28  constructed to accommodate cable  30 , or the solid filling members  26 , can be replaced with a filling member designed to accommodate cables having the thickness of cable  52 , using the simple method described above, where the clamping brackets are loosened, the shielding members replaced, and the clamping brackets tightened. Thus, the apparatus depicted in FIGS. 4 and 5 can be used to shield interference while allowing multiple cables of varying thickness to enter and exit the shielded cabinet.  
         [0027]    The above description and drawings are only illustrative of preferred embodiments which achieve the objects, features, and advantages of the present invention, and it is not intended that the present invention be limited thereto. Any modification of the present invention which comes within the spirit and scope of the following claims is considered to be part of the present invention.