Abstract:
Disclosed is an apparatus and method for connecting a power feeder cable at a point for convenient operator access to an electrical subsystem located inside of a telecom equipment assembly. According to one embodiment, the terminal connection of the power feeder cable to the power entry point is positioned so as to be conveniently accessible to an operator from the telecom equipment aisle. According to another embodiment, a linking bus structure comprising, a first connector, a conducting path and a second connector, is mounted inside the telecom equipment assembly with the first connector positioned at the front panel of the telecom equipment assembly and conveniently accessible to an operator from the telecom equipment aisle. The apparatus and method are useful for overcoming difficulties normally encountered during inspection and maintenance of the connection of the power feeder cable at its terminal connection in a telecom equipment assembly.

Description:
FIELD OF THE INVENTION 
     The present invention relates to electrical connectors, and more particularly, to positioning of electrical power connectors for convenient access and maintenance. 
     BACKGROUND OF THE INVENTION 
     A telecom equipment assembly is typically housed in a telecom equipment rack located within a telecom equipment room. Such a room typically contains rows of telecom equipment racks. These rows of telecom equipment racks define telecom equipment aisles. 
     Telecom equipment assemblies house electrical subsystems containing among other things, power supplies, which, for the most part, operate on relatively low voltage direct current (DC) electrical power in the range of zero to 60 volt DC power. Electrical power is supplied along heavy-duty large-diameter copper cables from battery equipment located in a battery room or plant or within telecom equipment racks themselves at a nominal 48 volts to the telecom equipment assemblies located in the telecom equipment room. The battery equipment under some circumstances functions as a power reservoir for the telecom equipment assemblies. The cables (“power feeder cables”) connecting the battery room to the telecom equipment assemblies within the telecom equipment room must be capable of conducting low voltage, high amperage, DC power with minimal resistance. The power feeder cables are typically run along overhead or in-floor troughs situated within corridors between the battery room and the telecom equipment rooms. 
     The power feeder cable normally terminates inside the telecom equipment assembly at a power entry point, which may be a terminal strip, bus bar or similar connection apparatus. The bus bar directs the electrical power to a power distribution module or to a breaker interface panel, and sometimes to a power converter. 
     The connection between the power feeder cable and the power entry point is often made through the use of a flat connector having a large surface area. The connection may be secured with a nut-and-lug type fastener. Over time, however, the contact between the power feeder cable and the power entry point begins to deteriorate as the nut begins to loosen due to heating of the contact through the interaction of electricity flowing through the cable and electrical resistance between the contact. Such heating results in the expansion of the components forming the contacts and ultimately loosening of the connection. If unchecked the loosening of the connection could result in power loss, or even scorching of the contacts. To prevent these consequences the connections must be inspected regularly and, if necessary, tightened by an operator. 
     This arrangement is well known in the art. However, a shortcoming in the existing art is that the connection between the power feeder cable and the power entry point is located inside of or at the rear of the telecom equipment assembly preventing convenient access to the connection. U.S. Pat. No. 3,924,161 to Olashaw et al. dated Dec. 2, 1975 is an example of an electrical switchboard having high voltage connections located at the back of the assembly. An operator typically must bring a step ladder into the equipment aisle and use it to gain entry to the inside of or the rear of a telecom equipment assembly in order to accomplish the task of inspecting and/or tightening the bolts thereby securing the connection between the power feeder cable and bus bar. This procedure is time consuming and presents potential hazards to the operator and the telecom equipment assembly itself. 
     In view of the foregoing, it would be desirable to provide a technique for connection of power feeder cables, which overcomes the above-described inadequacies and shortcomings. 
     SUMMARY OF THE INVENTION 
     The present invention improves access to the terminal connection of a power feeder cable at a power entry point to the telecom equipment assembly by positioning the connection to a more readily accessible location such as a side of the telecom equipment assembly that borders an equipment aisle or the front of the telecom equipment assembly. 
     According to a first aspect of the present invention there is disclosed an embodiment of a method for electrically linking at least one power feeder cable to an electrical subsystem located inside a telecom equipment assembly. The method comprises the steps of providing a power landing proximate to a side bordering an equipment aisle at a position so that an operator can conveniently access the power landing from the equipment aisle, electrically linking the power feeder cable to the power landing, and electrically linking the power landing to the electrical subsystem. 
     Advantageously the power landing may be situated behind a protective cover in order to prevent electrical faults or injury to an operator working in the equipment aisle. 
     Conveniently under some circumstances it may be useful to mount the power landing at a location on the telecom equipment assembly that is lower than about 2 meters from floor level of the equipment aisle. 
     Also advantageous in some circumstances is the use of a power landing which comprises a connector having at least one lug. The lug is capable of accepting a nut. Such a power landing is intended to function with a complementary connector capable of admitting the lug. The connection between this complementary connector and the power landing is then secured by engaging the lug with the nut. 
     According to another aspect of the present invention there is disclosed an embodiment of a telecom equipment assembly for installation along an equipment aisle. This embodiment comprises a power landing, an electrical subsystem located inside the telecom equipment assembly, and a conducting path electrically linking the power landing and the electrical subsystem. According to this embodiment, the telecom equipment assembly has a side portion that borders the equipment aisle. The power landing is located at a position relative to the telecom equipment assembly that is proximate to this side portion so that an operator can conveniently access the power landing from the equipment aisle. 
     Advantageously the power landing may be situated behind a protective cover in order to prevent electrical faults or injury to an operator working in the equipment aisle. 
     Conveniently under some circumstances it may be useful to position the power landing at a location on the telecom equipment assembly that is lower than about 2 meters from floor level of the equipment aisle. 
     Also convenient under some circumstances is the use of a bus bar as the conducting path in order to electrically link the power landing and the electrical subsystem. 
     Also advantageous is the use of a power landing which comprises a connector having at least one lug. The lug is capable of accepting a nut. Such a power landing is intended to function with a complementary connector capable of admitting the lug. The connection between this complementary connector and the power landing is then secured by engaging the lug with the nut. 
     According to yet another aspect of the present invention there is disclosed an embodiment of a linking bus structure for electrically linking at least one power feeder cable to an electrical subsystem located inside a telecom equipment assembly. The linking bus structure comprises: at least one first connector for electrically connecting the at least one power feeder cable, at least one second connector for electrically connecting the electrical subsystem, and at least one conducting path electrically linking the first and second connectors. According to this embodiment, the telecom equipment assembly has a side portion that borders the equipment aisle. The linking bus structure is positioned with the first connector proximate to this side portion so that an operator can conveniently access the first connector from the equipment aisle. 
     Advantageously the first connector may comprise a connector having at least one lug. The lug is capable of accepting a nut. Such a first connector is intended to function with a complementary connector capable of admitting the lug. The connection between this complementary connector and the first connector is then secured by engaging the lug with the nut. 
     Conveniently under some circumstances it may be useful to use an L-shaped connector having a surface complementary to the first connector and an end adapted to admit the power feeder cable. The connection between the L-shaped connector and the first connector is secured by engaging the lug with the nut. The end of the L-shaped connector is intended to attach to the power feeder cable. 
     Advantageously the conducting path used to electrically link the first and second connectors may be a first bus bar. 
     As yet another advantage the linking bus structure may further comprise an L-shaped support member defined by an arm and a post joined together at right angles, the L-shaped support member having a first end being an end of the arm opposite the joint, and a second end, being an end of the post opposite the joint. The L-shaped support member is adapted to attach the first connector at the first end and the second connector at the second end. Electrically linking the first connector to the second connector is a first bus bar. This bus bar is routed along the arm and the post. 
     Conveniently under some circumstances it may be useful for the linking bus structure to further comprise: a third connector adjacent to the first connector; a fourth connector adjacent to the second connector, a second bus bar electrically linking the third connector to the fourth connector, and at least one electrically insulative sheet disposed between the first and second bus bars. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be more clearly understood and more readily carried into effect, exemplary embodiments of the invention will now be described with reference to the accompanying drawings in which: 
         FIG. 1  is a diagram illustrating a telecom equipment room having a row of telecom equipment racks defining equipment aisles as typically found in the prior art; 
         FIG. 2  is a diagram illustrating a telecom equipment rack having a power entry point located at the top of the telecom equipment assembly typically found in the prior art; 
         FIG. 3  is a diagram illustrating a telecom equipment rack having a power landing located at the front of the telecom equipment assembly according to an embodiment of the present invention; 
         FIG. 4  is a diagram illustrating a linking bus structure according to an embodiment of the present invention; and 
         FIG. 5  is a diagram illustrating a linking bus structure mounted in a telecom equipment according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described in more detail with reference to exemplary embodiments thereof as shown in the appended drawings. While the present invention is described below including preferred embodiments, it should be understood that the present invention is not limited thereto. Those of ordinary skill in the art having access to the teachings herein will recognize additional implementations, modifications, and embodiments which are within the scope of the present invention as disclosed and claimed herein. In the figures, like elements are given like reference numbers. 
     Referring to  FIG. 1  there is illustrated a typical telecom equipment room known in the art. Telecom equipment racks, generally denoted by reference numeral  1 , stand about two meters tall (by convention) and they are typically housed in rows in a telecom equipment room which is defined by walls  2 . Rows of telecom equipment racks  1  define telecom equipment aisles  3 . Telecom equipment aisles  3  may be formed between two rows of telecom equipment racks  1 , or between a row of telecom equipment racks  1  and a wall  2  of the telecom equipment room. Typically telecom equipment aisles  3  are further demarcated as maintenance aisles  7  and wiring aisles  8 . A maintenance aisle  7  is bordered by either a wall  2  and a row of telecom equipment racks  1  or two rows of telecom equipment racks  1  such that the front or switch sides of the telecom equipment racks  1  face toward the maintenance aisle  7 . A wiring aisle  8  is bordered by either a wall  2  and a row of telecom equipment racks  1  or two rows of telecom equipment racks  1  such that the rear or port sides of the telecom equipment racks  1  face toward the wiring aisle  8 . It is often preferred that most telecom equipment assemblies  32  are accessed through the front or switch side of the telecom equipment rack  1  from a maintenance aisle  7 . 
     Referring now to  FIG. 2  there is illustrated a typical telecom equipment rack  1  that is well known in the art. Within any telecom equipment rack  1  there are regions that are inaccessible to an operator from a telecom equipment aisle, regions that are accessible but with some difficulty to an operator from a telecom equipment aisle, and regions that are conveniently accessible to an operator from a telecom equipment aisle  3 . The region containing the terminal connection of the power feeder cable  12  to the power entry point  13  in a prior art installation as depicted in  FIG. 2  is accessible to an operator from an equipment aisle  3  but with some difficulty. Notably, power feeder cables  12 , which eventually feed electrical power to the electrical subsystems  5 , terminate at a power entry point  13  located at the top or rear of the telecom equipment rack  1 . As can be seen in  FIG. 2 , the terminal connection of the power feeder cable  12  at the power entry point  13  of the telecom equipment assembly  32  being at the top of the telecom equipment rack  1 , is located at a position that is not conveniently accessible to an operator working in the equipment aisle  3 . 
     In this example, an operator is forced to bring a ladder or step stool into the telecom equipment aisle  3  to gain access to the top of the telecom equipment rack  1 , and the connection might be further located inside of the telecom equipment assembly  32  behind access panels (not shown) which obscure the operator&#39;s view of the connection. In such cases an operator may have to find the connection by touch before he or she can conduct maintenance on the connection itself. Regions of the telecom equipment racks that are conveniently accessible to an operator from an equipment aisle are reachable by an operator from the equipment aisle without the need for ladders, stools or special tools. Furthermore, regions that are conveniently accessible to an operator from the equipment aisle  3  afford an operator an unobscured view from an equipment aisle  3 . Operators that have power infrastructure in a raised or sub-floor, would run power feeder cables  12  from an opening in the raised sub-floor to the top of the telecom equipment racks  1 . This uses valuable rack space for routing of the power feeder cables  12 . 
     According to one embodiment of the present invention illustrated in  FIG. 3 , a power landing  16  is positioned on a telecom equipment assembly  32  at a side portion bordering an equipment aisle  3  so that an operator can conveniently access the power landing  16  from the equipment aisle  3 . The power feeder cable  12  is electrically linked to the power landing  16  and the power landing  16  is electrically linked to an electrical subsystem  5 . 
     The power landing  16  is ideally located lower than about 2 meters from floor level of the equipment aisle  3 . Such a position is conducive to convenient access to the power landing  16  by an operator from the equipment aisle  3 . 
     A protective cover  6  may be situated in front of the power landing  16  to prevent electrical faults or injury to an operator working in the equipment aisle  3 . The protective cover is constructed from an insulative material such as plastic. The protective cover  6  is mounted to the telecom equipment assembly  32  such that an operator can move it from a normally closed position to a position that provides the operator access to the power landing  16 . 
     According to a contemplated embodiment of the invention, the first connector  18  comprises a connector having at least one lug  20  capable of accepting a nut  24 . Such a first connector  16  is intended to function with a complementary connector  22 , preferably an L-shaped connector, capable of admitting the lug  20 . The connection between this complementary connector  22  and the first connector  18  is then secured by engaging the lug  20  with the nut  24 . 
     The L-shaped connector  22  may be attached to the power feeder cable  12  either by crimping, fusing with solder, or other methods well known in the art. The L-shaped connector  22  is complementary to the first connector  18 . For additional security, the L-shaped connector  22  may admit a plurality of lugs  20 . 
     It is contemplated that a telecom equipment assembly  32  may be installed along an equipment aisle  3 . The telecom equipment assembly  32  has a side portion that borders the equipment aisle  3 . A power landing  16  is mounted proximate to this side portion at a position that allows an operator convenient access to the power landing  16  from the equipment aisle  3 . Inside the telecom equipment assembly  32  there is located an electrical subsystem  5 . Electrically linking the power landing  16  to the electrical subsystem  5  is a conducting path  28 . The conducting path  28  can be any material capable of conducting electricity down its length, such as a copper wire, or other materials known in the art. 
     In some installations the conducting path  28  may be a bus bar. A bus bar is an electrical conductor that makes a common connection between several connectors. It is typically a thin flat type of conductor known in the art which has the necessary cross-sectional area necessary to preserve the electrical resistance required for the given application. 
     Referring now to  FIGS. 4 and 5 , reference numeral  10  denotes generally an embodiment of a linking bus structure for linking a power feeder cable  12  to an electrical subsystem  5  inside a telecom equipment assembly  32  such that a first connector  18  is accessible from outside of the telecom equipment assembly  32  on a side portion that borders the telecom equipment aisle  3 . Referring to  FIG. 4  the linking bus structure  10  is generally L-shaped. The L-shape of the linking bus structure  10  is defined by an arm  11  and a post  14  which join to resemble an L-shape. Located at the end of the arm  11  opposite the post  14  is at least one power landing  16 . The power landing  16  comprises at least one first connector  18 . There are four such first connectors  16  depicted in  FIG. 4 , each of which could admit a separate power feeder cable, however, it is to be noted that the number of first connectors  16  constituting a power landing  18  could be increased or decreased. 
     Attached to one end of the power feeder cable  12  is an L-shaped connector  22 . The L-shaped connector  22  may be attached to the power feeder cable  12  either by crimping, fusing with solder, or other methods well known in the art. The L-shaped connector  22  is complementary to the first connector  18 . The L-shaped connector  22  is secured to the first connector  18  with a nut  24  that engages the lug  20  that forms a part of the first connector  18 . For additional security, the L-shaped connector  22  may admit a plurality of lugs  20 . 
     It should be noted, however, that although only one embodiment of the first connector  16  is herein described other embodiments are contemplated by the present invention. It should be noted, however, that although only one embodiment of the power landing  16  and first connector  18  is herein described other embodiments are contemplated by the present invention. For example, first connector  18  could comprise threaded conductive bolts securing complementary connectors  22  to threaded receptacles in the power landing  16 . Alternate terminal block means known to those skilled in the art are also contemplated. 
     Attached to the post  14  is a second connector  26  which can connect an electrical subsystem  5 . A conducting path  28  runs from each power landing  16  along the arm  11  and along the post  14  to the second connector  26 . The conducting path  28  may be a bus bar. A bus bar is a thin flat type of conductor known in the art. A conducting path  28  which consists of a bus bar may be used to save space inside of the telecom equipment assembly  32  by running nearly flush with the surface of the arm  11  and post  14  while maintaining the necessary cross-sectional surface area necessary to preserve the electrical resistance required for the given application. 
     It is contemplated that the linking bus structure  10  can comprise multiple first connectors  18  electrically link to multiple second connectors  26  through multiple bus bars  28  such that each of the first connectors  18  corresponds to a specific second connector  26 . 
     When more than one bus bar is used as the conducting path  28 , they may be mounted to the post  14  in a stacked relationship in respect of each other with an electrically insulative sheet  30  disposed therebetween. The insulative sheets  30  may be any electrically non-conductive material that can be inserted between adjacent conducting paths  28 . The purpose of the insulative sheets  30  is to prevent electrical faults caused by two conducting paths  28  making contact with each other, and the insulative characteristics and dimensions must be sufficient to withstand voltage stresses as may occur between bus bars  28 . 
     As shown in  FIG. 5 , the linking bus structure  10  is mounted inside of a telecom equipment assembly  32  such that the power feeder cable  12  and second connector  26  are located inside of the telecom equipment assembly  32  while the first connector  18  is accessible from outside of the telecom equipment assembly  32 . A protective cover  6  may be used to cover the first connector  18  when access to the first connector  18  is not required. The purpose of the protective cover  34  is, among other things, to prevent electrical faults and inadvertent shocks to operators working in the equipment aisle  3 . 
     While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims. Further, although the present invention has been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the present invention can be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in view of the full breath and spirit of the present invention as disclosed herein.