Abstract:
A self-sealing apparatus for containing electrical energy associated with electrical components. The apparatus includes one or more removable devices maintained by a housing. Each of the removable devices contains electrical components therein and is separated from at least one other removable device by a clearance gap formed therebetween. A self-sealing barrier can be formed from the clearance gap, wherein the clearance gap surrounds the removable device in order to contain electrical energy associated with the electrical components when the electrical components are maintained within the removable device or extracted or inserted from or into the removable device.

Description:
TECHNICAL FIELD 
   Embodiments are generally related to EMC (Electromagnetic Compatibility) and RFI (Radio Frequency Interference) components and devices. Embodiments are also related to EMC sealing devices for an electrical enclosure. 
   BACKGROUND OF THE INVENTION 
   The past several decades have witnessed the development of ever smaller electrical circuit components at the chip level. In order to take fullest advantage of achievements in electrical circuit miniaturization; however, one must package the resultant printed circuit cards containing these chips in an efficient manner. Clearly, the packaging of printed circuit cards in tight spaces is a direct logical extension of increasing chip level circuit densities. It should also be noted that the tight packaging of integrated circuit chips on printed circuit cards and the correspondingly dense packaging of the printed circuit cards is a design goal that is carried out for more than just the convenience of compactness. Compactness provides shorter distances between circuit components which, in turn, serve the very desirable goal of being able to operate the circuits effectively at higher frequencies, thus increasing the speed of numerous different forms of electrical systems, including but not limited to data processing systems. 
   Moreover, mainly for reasons associated with long-term system operation and reliability, it is likewise very desirable to be able to easily insert and remove these printed circuit cards even when they are disposed in very tight spaces. The insertion and removal operations are also provided as an important part of a “hot-pluggability” function which is very desirable for “on the fly” repairs, replacements, maintenance and upgrades. Accordingly, to whatever extent possible, packaging designs should be: economical to produce; function smoothly, require little or no maintenance; be producible from inexpensive, readily available materials; and be reliably operable over a large number of insertion and removal operation cycles. 
   Yet one other concern arises in electrical systems as circuit feature size shrinks, operating frequencies increase and packaging densities grow larger, namely, the generation of electromagnetic interference (EMI). Electronic circuit packaging designs should thus also be compatible with structures and configurations that are employed to prevent the leakage of electromagnetic interference. 
   Packaging designs should also include structures, which actually contribute positively to the containment of electromagnetic interference. There is an ever-increasing problem of electromagnetic interference caused by such devices. Virtually every electronic device, intentionally or not, emits some form of electromagnetic radiation. While this condition could be tolerated when few devices existed, the increasing number of electronic devices has made the problem more acute. The problem has been exacerbated by the “improvement” in semiconductor devices, which allows them to operate at higher speeds, generally causing emission in the higher frequency bands where interference is more likely to occur. 
   Successful minimization of the interference problem, sometimes referred to as “electromagnetic compatibility” or “EMC”, generally requires that emissions from a given device be reduced by shielding and other means, and shielding be employed to reduce the sensitivity of a device to fields from other devices. Since shielding helps to reduce sensitivity to external fields as well as reduce emissions from the device, it is a common approach to a solution of the problem. 
   In the typical enclosure for a computer, for example, a number of electronic components are mounted therein. Such components include, for example, a central processing unit (CPU), a microprocessor, random access memory (RAM), read only memory (ROM) and other computer chips and electronic devices. Such electronic components may emit electromagnetic radiation during their operations. Data-processing devices, such as computers are typically manufactured with expansion slots to allow peripheral devices to be added to the computer or system. In such configurations, much of the electromagnetic radiation can leak out through the expansion slots to potentially interfere with other electronic components. 
   Typically, a number of cover plates are attached to a rear panel and block the expansion slots thereon. However, as the internal circuitry of computers has advanced, the cover plates can be inadequate to block the electromagnetic radiation. The inadequacy of the cover plates is believed to be due to gaps between the cover plates and the computer enclosure. In order to overcome such drawbacks, it is believed that a solution involves the implementation of a removable device containing EMC/RFI energy that can be contained by a continuous perimeter grounding seal or barrier. Such features are described in greater detail herein. 
   BRIEF SUMMARY 
   The following summary of the invention is provided to facilitate an understanding of some of the innovative features unique to the present invention and is not intended to be a full description. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings and abstract as a whole. 
   It is therefore one aspect of the present invention to provide for an apparatus for containing EMC and/or RFI energy associated with electrical components. 
   It is another aspect of the present invention to provide for an improved EMC sealing device for an electronics enclosure. 
   It is a further aspect of the present invention to provide for a self-sealing EMC door for removable units requiring a continuous grounding barrier. 
   The above and other aspects of the invention can be achieved as will now be briefly described. A self-sealing apparatus for containing electrical energy associated with electrical components is disclosed, which includes one or more removable devices maintained by a housing. Each of the removable devices contains electrical components therein and is separated from at least one other removable device by a clearance gap formed therebetween. A self-sealing barrier can be formed from the clearance gap, wherein the clearance gap surrounds the removable device in order to contain electrical energy associated with the electrical components when the electrical components are maintained within the removable device or extracted or inserted from or into the removable device. 
   A door can be associated with each removable device, wherein the door comprises a plurality of inlet holes, which allows air to flow therethrough and reduce heating associated with the electrical components. Additionally, a handle can be with removable device, wherein the handle provides leverage for opening the self-sealing barrier about the door. A first gasket can be formed horizontally across the housing, while a second gasket can be formed vertically along a pivot edge of the door, such that when the door is closed the door compresses the first and second gaskets against another removable device or against the housing in order to provide the self-sealing barrier thereof. 
   Each inlet hole among the plurality of inlet holes comprises a length thereof that functions as wave-guides that absorb the electrical energy coming into contact with an inner surface of each inlet hole. The self-sealing barrier (i.e., a seal) can be configured as a conductive seal formed from a conductive material with a low impedance to electrical current. The self-sealing barrier can also be configured as a continuous perimeter grounding seal surrounding the removable device. The housing can be configured as a chassis cage. The electrical energy associated with the electrical components typically comprises EMC and/or RFI energy. 
   The apparatus disclosed herein is thus directed toward a removable device containing EMC/RFI energy that radiates if not contained by a continuous perimeter grounding seal or barrier. To avoid the device clearance gaps from becoming antennas, the gaps must be sealed. Additional features include airflow passage and handle leverage extraction. 
   The removable device can be implemented, for example, in the context of a Customer Removable Unit (CRU) of a Data Storage Tray. The device is extractable by using the handle described above as a leverage to open the perimeter ground seals around the device door. The handle and door then act as a pulling feature to extract the device. Insertion is preformed in the reverse order. The device can contain Electronic items like disk drives, power supplies, circuit boards, and etc. each having EMC/RFI characteristics. The number of devices can range from one to as many as the chassis cage can contain. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying figures, in which like reference numerals refer to identical or functionally similar elements throughout the separate views and which are incorporated in and form part of the specification, further illustrate embodiments of the present invention. 
       FIG. 1  illustrates a pictorial diagram depicting a set of four removable devices inserted in a chassis cage, in accordance with a preferred embodiment; 
       FIG. 2  illustrates a pictorial diagram illustrating four removable devices in accordance with a preferred embodiment; 
       FIG. 3  illustrates a pictorial diagram depicting an extraction sequence in accordance with a preferred embodiment; 
       FIG. 4  illustrates a pictorial diagram illustrating a configuration of EMC/RFI gaskets in accordance with a preferred embodiment; 
       FIG. 5  illustrates a pictorial diagram depicting the intersection of EMC/RFI seals in accordance with a preferred embodiment; 
       FIG. 6  illustrates a pictorial diagram illustrating closed EMC/RFI seals in accordance with a preferred embodiment; 
       FIG. 7  illustrates a pictorial diagram depicting EMC/RFI cage seals in accordance with a preferred embodiment; and 
       FIG. 8  illustrates a top view of a configuration depicting cam action and compression of EMC/RFI gaskets in accordance with a preferred embodiment. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate embodiments of the present invention and are not intended to limit the scope thereof. 
   The embodiments disclosed herein describe a removable device containing EMC/RFI (Electromagnetic Compatibility/Radio Frequency Interference) energy that can radiate if not contained by a continuous perimeter grounding seal or barrier. To avoid the device clearance gaps from becoming antennas, the gaps are sealed. Additional features include airflow passage and handle leverage extraction. Note that as utilized herein, the term Electromagnetic Compatibility (EMC) generally refers to an electrical system&#39;s ability to perform its specified functions in the presence of electrical noise generated either internally or externally by other systems. The goal of EMC is to minimize the influence of electrical noise. Radio Frequency Interference (RFI), on the other hand, is considered part of the Electromagnetic Interference (EMI) spectrum, with interference signals being within the radio frequency (RF) range. Electromagnetic Interference (EMI) generally refers to the electromagnetic energy from sources external or internal to electrical or electronic equipment that adversely affects equipment by creating undesirable responses (degraded performance or malfunctions). 
   The removable device can be implemented in the context of a Customer Removable Unit (CRU) of a Data Storage Tray. The device is extractable utilizing a handle as a leverage to open the perimeter ground seals around the device door. The handle and door then act as a pulling feature to extract the device. Insertion is preformed in the reverse order. The device can contain electronic items such as, for example, disk drives, power supplies, circuit boards, and the like, each having EMC/RFI characteristics. The number of devices can range from one to as many as the chassis cage can contain, depending on design considerations. 
     FIG. 1  illustrates a pictorial diagram depicting a system  41  that includes a group  13  of four removable devices  25 ,  26 ,  27 ,  29  inserted in a chassis cage  14 , in accordance with a preferred embodiment. Each item or device  25 ,  26 ,  27 ,  29  of system  41  respectively include a door  15 ,  16 ,  17 ,  19 . The basic concept of system  41  includes the chassis cage  14  partially or completely filled with removable devices  25 ,  26 ,  27 ,  29  with EMC/RFI energy. Door  16 , for example, provides an EMC/RFI seal, along with an airflow passage and an extraction handle. Similar features can be incorporated into doors  15 ,  17  and  19 . 
     FIG. 2  illustrates a pictorial diagram illustrating in greater detail the four removable devices  25 ,  26 ,  27 ,  29  depicted in  FIG. 1 , in accordance with a preferred embodiment. Note that in  FIGS. 1–8  herein, identical or similar parts or elements are generally indicated by identical reference numerals. Each removable device  25 ,  26 ,  27 ,  29  comes equipped with a door with an extraction example. For example, as depicted in  FIG. 2 , removable device  26  includes a door  16  with an extraction handle  18 . Each removable device  25 ,  26 ,  27 ,  29  comes equipped with perimeter gaskets. For example, perimeter gaskets  22  and  24  are depicted in  FIG. 2 . In the configuration of  FIG. 2 , perimeter gasket  24  is associated with removable device  29 , which in turn is associated with door  19 . Such perimeter gaskets promote RFI sealing. 
   Each door  15 ,  16 ,  17 ,  19  also comes equipped with airflow inlets to promote the flow of air for cooling each respective item or device  25 ,  26 ,  27 ,  29 . For example, as depicted in  FIG. 2 , door  15  is configured to incorporate a plurality of airflow inlets  8 , while door  16  incorporates a plurality of airflow inlets  9 . Similarly, door  17  incorporates a plurality of airflow inlets  10  and door  19  incorporates a plurality of airflow inlets  11 . 
   As further indicated in  FIG. 2 , removable device  26  is associated with a removable portion  36  that provides a mounting for the electronic items thereof that generate EMC/RFI energy. These items can range from disk drives, power supplies, circuit boards and any other interface item that may generate EMC/RFI energy. The mounting may also provide for electrical interconnection with other items in the chassis or cage. 
     FIG. 3  illustrates a pictorial diagram depicting an extraction sequence in accordance with a preferred embodiment. In general, extraction of the removable portion  36  of removable device  26  begins by opening the door  16  with some type of handle  18 . This releases the EMC/RFI gaskets thereof and allows the removable portion  36  to clear other devices. Pulling on the handle  18  removes the device from the chassis cage  14 , as depicted in  FIG. 3 . A sequence of events at time T 1 , T 2  and T 3  is generally depicted in  FIG. 3 . 
     FIG. 4  illustrates a pictorial diagram illustrating a configuration of EMC/RFI gaskets in accordance with a preferred embodiment. In the example depicted in  FIG. 4 , the door  16  can open on a pivot pin  37  allowing it to rotate to approximately 90-degrees from the sealed position. In the sealed position the door  16  is surrounded on all edges with electrically conductive gaskets providing ground contact with the adjacent devices and the chassis cage  14 . The horizontal gasket  22  is attached to the chassis cage  14  and seals the top and bottom of all doors  16  of the devices continuously. 
     FIG. 5  illustrates a pictorial diagram depicting the intersection of EMC/RFI seals in accordance with a preferred embodiment. The door  16  has features for leveraging the removable portion  36  for insertion and extraction. This feature can take on many shapes to accomplish the cam action  30  needed for insertion and extraction. The leverage may be needed for connecting or disconnecting the device from other items in the chassis or cage  14 . The door  16  may or may not contain an attached handle  18  used for opening and extraction of the device  36 . The handle  18  can be as simple as a knob or as complex as a compound surface used for styling. The main function of the handle  18  is to rotate the door  16  about the pivot  34  and assist in extraction and insertion. 
     FIG. 6  illustrates a pictorial diagram illustrating closed EMC/RFI seals in accordance with a preferred embodiment. Each device  25 ,  26 ,  27 ,  29  has a clearance gap surrounding it to allow the devices  25 ,  26 ,  27 ,  29  to be easily extracted or inserted. This clearance gap  12  (e.g., see  FIG. 8 ) contains energy from the electronics inside the device and will become a radiating antenna. Opening and closing the door  16  applies the pressure that seals the gaskets surrounding the door  16 . This gasket  22  is of conductive material with low impedance to electrical current. 
   When closed, the door  16  compresses the gasket against the next device or against the chassis cage  14 . This provides a tight conductive seal around each of the devices  25 ,  26 ,  27 ,  29 . The gasket  24  is fastened to the attached surface  20  that rotates around the door pivot  34 . The attached surface  20  is designed to place the gasket  22  against and slightly behind the door  16  sealing surface  28  of the adjacent device completing the seal that surrounds the door  16 . The gasket attaches to surface  20  and the gasket-sealing surface  28  are slightly angled to block a straight-line gap. 
     FIG. 7  illustrates a pictorial diagram depicting EMC/RFI cage seals in accordance with a preferred embodiment. In  FIG. 7 , a rear perspective view  70  is depicted, along with a top view  71  of the EMC/RFI cage seals. Electronic item  26 , for example, can generate heat as well as EMC/RFI energy. Therefore the door  16  needs to have inlets  10  for ambient air enter the removable portion  36  and, at the same time, are solid enough to block EMC/RFI energy from escaping the removable portion  36 . The front surface of the door  16  contains long holes (e.g., inlet  9 ) for permitting air to enter. Similar features are present for each of the devices  25 ,  26 ,  27 ,  29 . For example, door  17  includes a plurality of airflow inlets or holes  10 . The length of such holes act as a wave-guides that absorb energy hitting the inter surfaces of the hole. The shape of the hole can be round or rectangular, but hexagon is preferred to maximize the air inlet openings. The dimensions of the hole diameter and the depth determine the effectiveness of the air let  10  versus the EMC/RFI energy emission. Opening and closing the door  16 , for example, applies the pressure that seals the gaskets surrounding the door  16 . 
   It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.