Abstract:
A method of manufacturing a load buss array assembly includes placing a plurality of load conductors within a thermally conductive substrate, placing a portion of a load connector within the thermally conductive substrate, and electrically connecting the load conductors to the portion of the load connector within the thermally conductive substrate.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/670,741, filed Jul. 12, 2012, which is incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    The disclosed concept pertains generally to load modules and, more particularly, to load buss assemblies for such load modules. The disclosed concept further pertains to methods of manufacturing load buss assemblies. 
         [0004]    2. Background Information 
         [0005]    U.S. Pat. No. 8,094,436 discloses a plug-in circuit breaker panel including a housing, an electrical bus structure coupled to the housing, and a number of first plug-in members coupled to the electrical bus structure. A number of circuit breakers include a first surface and a second plug-in member disposed opposite the first surface. The second plug-in member of each of the number of circuit breakers is mated with a corresponding one of the number of first plug-in members. A plate member is removably coupled to the housing. The plate member includes a first surface and an opposite second surface. The first surface of the number of circuit breakers engages the opposite second surface of the plate member in order to maintain mating of each of the number of circuit breakers with the corresponding one of the number of first plug-in members. 
         [0006]    The rear of the plug-in circuit breaker panel includes first and second feeders for a three-phase alternating current (AC) system. Typically, for each of the feeders, there can be a single three-pole AC circuit breaker and a plurality of single pole AC circuit breakers for each of the three phases. For example, each of the feeders is a three-terminal terminal block having three power terminals for the three phases of the corresponding feeder. A first surface of the electrical bus structure is proximate the number of first plug-in members, and the feeders and power terminals thereof are coupled to the opposite second surface along with a number of load connectors. The load connectors include load outputs (e.g., loads) from the corresponding circuit breakers associated with the respective feeders. In a similar manner, the power inputs (e.g., lines) to the corresponding circuit breakers are associated with the respective feeders. The electrical bus structure (e.g., a number of inner power layers thereof) suitably routes the load outputs from and the power inputs to the various circuit breakers. 
         [0007]    While the feeders are directly coupled to the electrical bus structure at corresponding terminal blocks and power terminals thereof, the load outputs from the circuit breakers are electrically connected between the electrical bus structure and corresponding load connectors by a number of discrete conductors or ribbon cable. As a result, a manual operation is needed to electrically connect the load outputs between the electrical bus structure and the corresponding load connectors. Also, the load connectors and the discrete conductors or ribbon cable significantly increase the size of the plug-in circuit breaker panel. 
         [0008]    Therefore, there is room for improvement in circuit breaker panels. 
         [0009]    There is also room for improvement in load buss assemblies of circuit breaker panels. 
         [0010]    There is further room for improvement in methods of manufacturing load buss assemblies of circuit breaker panels. 
       SUMMARY 
       [0011]    These needs and others are met by aspects of the disclosed concept which place a plurality of load conductors within a thermally conductive substrate; place a portion of a load connector within the thermally conductive substrate; and electrically connect the load conductors to the portion of the load connector within the thermally conductive substrate. 
         [0012]    In accordance with one aspect of the disclosed concept, a load buss array assembly comprises: a thermally conductive substrate; a plurality of load conductors placed within the thermally conductive substrate; and a portion of a load connector placed within the thermally conductive substrate, wherein the load conductors are electrically connected the portion of the load connector within the thermally conductive substrate. 
         [0013]    In accordance with another aspect of the disclosed concept, a method of manufacturing a load buss array assembly comprises: placing a plurality of load conductors within a thermally conductive substrate; placing a portion of a load connector within the thermally conductive substrate; and electrically connecting the load conductors to the portion of the load connector within the thermally conductive substrate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: 
           [0015]      FIG. 1A  is an isometric view of a plurality of miniature conductive traces for a load buss array assembly in accordance with embodiments of the disclosed concept. 
           [0016]      FIG. 1B  is an exploded isometric view of the miniature conductive traces of  FIG. 1A , a thermally conductive substrate and a load connector for a load buss array assembly in accordance with another embodiment of the disclosed concept. 
           [0017]      FIG. 1C  is an isometric view of the miniature conductive traces and the load connector of  FIG. 1B . 
           [0018]      FIGS. 2A and 2B  are an isometric view and a side vertical elevation view, respectively, showing the load conductive traces of a load buss array assembly of a load module assembly in accordance with another embodiment of the disclosed concept. 
           [0019]      FIGS. 3A and 3B  are an isometric view and a side vertical elevation view, respectively, of a circuit breaker panel including the load module assembly with embedded feeder layers and the load buss array assembly of  FIG. 2A . 
           [0020]      FIG. 4  is a plan view of the circuit breaker panel of  FIG. 3A  with a cover removed to show a load connector. 
           [0021]      FIGS. 5A and 5B  are an isometric view and a side vertical elevation view, respectively, of a backplane module including the embedded feeder layers and the load buss array assembly of  FIG. 2A . 
           [0022]      FIG. 6  is a plan view of the embedded feeder layers of the backplane module of  FIG. 5A  with the load buss array assembly removed. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality). 
         [0024]    As employed herein, the statement that two or more parts are “connected” or “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts. Further, as employed herein, the statement that two or more parts are “attached” shall mean that the parts are joined together directly. 
         [0025]    The disclosed concept employs miniature conductive traces embedded in a thermally conductive substrate as part of a method of construction and automated electrical connection of a load connector to a plurality of load buss array miniature conductive traces. This method simplifies the construction of a load module, and provides considerable size, depth and weight benefits as compared to known methods of packaging a wiring interconnect. 
         [0026]    The disclosed concept preferably provides: (1) a 100% thermally conductive backplane; and (2) a 100% embedded load conductor solution. 
         [0027]    The materials of the miniature conductive traces can be, for example, copper or aluminum. 
         [0028]    The materials of the thermally conductive substrate can be relatively highly heat-resistant resins like a liquid-crystal polymer (LCP) or polyetheretherketone (PEEK). 
         [0029]    The disclosed concept is described in association with subminiature or aircraft circuit breakers, although the disclosed concept is applicable to a wide range of different circuit breakers for a wide range of different applications. Such circuit breakers can be employed, for example and without limitation, in aircraft alternating current (AC) systems having a typical frequency of about 400 Hz, but can also be used in direct current (DC) systems. It will also become evident that the disclosed concept is applicable to other types of circuit breaker panels including those used in AC systems operating at other frequencies; to larger circuit breakers, such as miniature residential or commercial circuit breakers; and to a wide range of circuit breaker applications, such as, for example, residential, commercial, industrial, aerospace, and automotive. As further non-limiting examples, both AC (e.g., without limitation, 120, 220, 480-600 VAC) operation at a wide range of frequencies (e.g., without limitation, 50, 60, 120, 400 Hz, and higher or lower frequencies) and DC operation (e.g., without limitation, 42 VDC) are possible. As still further non-limiting examples, single phase and plural phase (e.g., without limitation, three phase) operation are possible. 
         [0030]    The miniature conductive traces  2  of a load buss array assembly  4  ( FIGS. 1B and 1C ) are suitably embedded in a thermally conductive substrate  6  ( FIG. 1B ). For example and without limitation, the thermally conductive substrate  6  is suitably molded or machined to have grooves  8  and holes  10  to accept the miniature conductive traces  2  as shown in  FIG. 1B . The corresponding load module  12  ( FIGS. 2A and 2B ) replaces a known prior load module (not shown) having discrete wiring over-molded into urethane and attached to an embedded feed section via sockets. See, for example, U.S. Pat. No. 8,094,436, which is incorporated by reference herein. 
         [0031]    The disclosed method simplifies the construction of the load buss array assembly  4  and, thus, the load module  12 . This permits, for example, the miniature conductive traces  2 , which function as load conductors, to be embedded in the molded thermally conductive substrate  6  (e.g., without limitation, a liquid-crystal polymer (LCP), such as CoolPoly® E-series thermally conductive plastic marketed by Cool Polymers, Inc. of North Kingstown, R.I.; a suitable thermally conductive and electrically insulative epoxy), which seals and insulates the load conductors. 
         [0032]    Alternatively, if the thermally conductive substrate  6  is machined, then the load conductors can be sealed and insulated (e.g., a conductor is placed in a channel and is sealed and insulated from other conductors and from the outside environment) by employing a suitable sealant (not shown) such as, for example and without limitation, tape, glue or epoxy. For example, the material is electrically insulative with adhesive on both sides, and is relatively very thin (e.g., without limitation, 0.005 in.) and conforms to the substrate  6  and traces  2 . 
         [0033]    The miniature conductive traces  2  can be automatically coupled to a load connector  14  and its load pins  15  ( FIGS. 1B and 1C ) by fixturing and by employing a conventional wave soldering process. For example, the load conductors are placed in the thermally conductive substrate  6  during molding, and the load connector  14  is fixtured to have a precise location and fit. Then, the load buss array assembly  4  is fed through a suitable wave soldering station (not shown) to electrically couple the connector load pins  15  and the load connector  14  to the load conductor traces  2 . Alternatively, this could be a manual operation, but would not be cost favorable. This eliminates point-to-point wiring attachments (e.g., without limitation, crimps; hand soldering). The disclosed concept adds about another 0.25″ of depth for the load thermally conductive substrate layers  16 , which are directly coupled to feeder layers  18  of the load module  12  ( FIGS. 2A ,  2 B,  3 A and  3 B). Also, a significant overall depth reduction to about 1″ to about 2″ from about 4″ to about 5″ of baseline depth is provided for the corresponding circuit breaker panel  20  ( FIGS. 3A ,  3 B and  4 ). 
         [0034]      FIG. 4  shows the circuit breaker panel  20  with its cover  22  (shown in  FIGS. 3A and 3B ) removed to show the load connector  14 . 
         [0035]      FIGS. 5A and 5B  show the backplane module  24  of the circuit breaker panel  20 . 
         [0036]    Various possible methods to place the load conductors within the thermally conductive substrate  6  include: (1) over-molding the miniature conductive traces  2  into the thermally conductive substrate  6 ; (2) hand placement of the miniature conductive traces  2  into the thermally conductive substrate  6 ; and (3) automated bobbin winding placement if the miniature conductive traces  6  have a suitable cross-section (e.g., without limitation, flat; round; square). For example, for the latter method, an uncoated load conductor (not shown) is placed with a CNC (x,y,z) controlled winder (not shown), such that a placed wire conductor (e.g.,  2  of  FIG. 2A ) is cut and placed without the use of manual touch-labor. The automated winding placement is suited to high-volume production, much like a wire feeder. This precisely feeds a wire cut length (not shown) to a nozzle (not shown), which is CNC-controlled to place the conductor (e.g.,  2  of  FIG. 1A ) into a groove  8  ( FIG. 1B ) in the thermally conductive substrate  6  ( FIG. 1B ). 
         [0037]    While specific embodiments of the disclosed concept have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof.