Abstract:
Contact bands for electrically connecting pluggable circuit breakers to ground and to distribution wires in a wiring system are housed in respective housings for protection. The housings are mounted on modular circuit breaker bus bar assemblies adapted to pluggably receive the pluggable circuit breakers, which have posts for pluggably engaging associated contact bands.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/057,453, filed Sep. 3, 1997 and U.S. Provisional Application No. 60/068,357, filed Dec. 19, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to pluggable circuit breakers, and particularly to a method and apparatus for mounting pluggable circuit breakers in a power distribution system. 
     2. Description of Related Art 
     Illustrated in FIG. 1 is a prior art pluggable circuit breaker  30 , having two circuit breaker posts  32  (only one shown) and a signaling module  33  having pins  35  for providing signals indicative of the status of the circuit breaker  30 —that is, whether the circuit breaker has been tripped or not. To create a pluggable circuit breaker, internally threaded circuit breaker pins  34  are threaded onto each of the threaded circuit breaker posts  32 . On the exterior of each circuit breaker pin  34  is attached a resilient electrical contact band  36 . The electrical contact band  36  is typically a thin metallic band with resilient fingers having an arcuate configuration and extending outward from the circuit breaker pin outer diameter. The addition of the circuit breaker pins  34  with outer electrical contact bands  36  to the circuit breaker  30  allows for pluggability of the circuit breaker  30  into a circuit breaker panel (not shown). Although this prior art configuration has some advantages, the outer electrical contact bands  36  are known to become damaged, loosened, or become completely removed from the pin  34 . In addition, there are many inherent costs in placing the electrical contact band  36  on the circuit breaker pin  32  which results in the circuit breaker going from a relatively economical, throw-away part to a more expensive part. 
     As a result of these limitations and disadvantages, there is a long-felt need in the art for a more robust, versatile, and cost effective design for pluggable circuit breakers and circuit breaker panels. 
     SUMMARY OF THE INVENTION 
     The present invention provides a pluggable circuit breaker mounting system in which electrical contact bands are protected within a housing. In addition, the present invention provides convenient modularity in the design of the circuit breaker panel and the attendant electrical contacts thereto. 
     In an arrangement in accordance with the preferred embodiment of the invention, the mounting system comprises one or more electrically connected circuit breaker bus bar assemblies, with each assembly comprising a panel having first and second housings mounted thereon. The housings each correspond to a post of a pluggable circuit breaker, the posts plugging into first and second contact bands respectively mounted in the first and second housings. A third contact band is also mounted in the second housing co-extensively with the second contact band, and the two contact bands in the second housing may be supported electrically and structurally within the second housing by a conductive sleeve. 
     In an arrangement in accordance with a second embodiment of the invention, the sleeve is replaced by a pin contact having a socket portion and a post portion, with only a second contact band, housed in the socket portion, being used in addition to the contact band in the first housing. 
     In an arrangement in accordance with a third embodiment of the invention, the sleeve which houses the second contact band is electrically connected to a one or more posts mounted outside the second housing to thereby provide electrical access to the second contact band and the second post of the circuit breaker from the exterior of the second housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Many advantages of the present invention will be apparent to those skilled in the art with a reading of this specification in conjunction with the attached drawings, wherein like reference numerals are applied to like elements and wherein: 
     FIG. 1 is a schematic diagram of a prior art pluggable circuit breaker; 
     FIG. 2 is a rear perspective view of a modular, pluggable circuit breaker mounting system in accordance with the preferred embodiment of the invention; 
     FIG. 3 is a front perspective view of the circuit breaker panel assembly of FIG. 2; 
     FIG. 4 is an perspective view of a contact band in accordance with the invention; 
     FIG. 5 is a top plan view of the circuit breaker panel assembly of FIG. 3; 
     FIG. 6 is a front elevational view of the circuit breaker panel assembly of FIG. 3; 
     FIG. 7 is a right side elevational view of the circuit breaker panel assembly of FIG. 3; 
     FIG. 8 is a cross-sectional view taken line  8 — 8  of FIG. 6; 
     FIG. 9 is a longitudinal cross-sectional view of a conducting sleeve in accordance with the invention; 
     FIG. 10 is a transverse cross-sectional view of the conducting sleeve of FIG. 9; 
     FIG. 11 is a top plan partial cross-sectional view of the ground bus bar of FIG.  3 . 
     FIG. 12 is a front elevational view of a ground bus bar of FIG.  3 . 
     FIG. 13 is a top plan partial cross-sectional view of an insulated housing of FIG. 3; 
     FIG. 14 is a front elevational view of the insulated housing of FIG. 3; 
     FIG. 15 is an enlarged cross-sectional view taken along line  8 — 8  of FIG. 6; 
     FIG. 16 is a front perspective view of a circuit breaker bus bar assembly in accordance with a second embodiment of the present invention; 
     FIG. 17 is a top plan view of the circuit breaker panel assembly of FIG. 16; 
     FIG. 18 is a front elevational view of the circuit breaker bus bar assembly of FIG. 16; 
     FIG. 19 is a right side elevational view of the circuit breaker bus bar assembly of FIG. 16; 
     FIG. 20 is a top plan partial cross-sectional view of an insulated housing of FIG. 16; 
     FIG. 21 is a front elevational view of the insulated housing of FIG. 20; 
     FIG. 22 is a right side elevational partial cut-away view of the circuit breaker bus bar assembly of FIG. 16; 
     FIG. 23 is a rear perspective view of the circuit breaker bus bar assembly of FIG. 16; 
     FIG. 24 is a right side elevational view of the circuit breaker bus bar assembly of FIG. 16; 
     FIG. 25 is a right side elevational partial cut-away view of the circuit breaker bus bar assembly having an auxiliary terminal connector in accordance with the invention; 
     FIG. 26 is a rear perspective view of the circuit breaker bus bar assembly of FIG. 25; 
     FIG. 27 is a front perspective view of circuit breaker bus bar assembly in accordance with a third embodiment of the present invention; 
     FIG. 28 is a top plan view of the circuit breaker bus bar assembly of FIG. 27; 
     FIG. 29 is a front elevational view of the circuit breaker bus bar assembly of FIG. 27; 
     FIG. 30 is a right side elevational view of the circuit breaker bus bar assembly of FIG. 27; 
     FIG. 31 is a partial cut-away view of a sleeve of the circuit breaker bus bar assembly of FIG. 27; 
     FIG. 32 is a transverse cross-sectional view of the sleeve of FIG. 31; 
     FIG. 33 is top plan view of the insulating housing of the circuit breaker bus bar assembly of FIG. 27; 
     FIG. 34 is a partial cross-sectional view of the insulated housing of FIG. 33; 
     FIG. 35 is a front elevational view of the insulating housing of FIG. 33; 
     FIG. 36 is a front elevational view of an L-bracket of the circuit breaker bus bar assembly of FIG. 27; 
     FIG. 37 is a right side elevational view the L-bracket of FIG. 36; 
     FIG. 38 is an exploded perspective view of a pair of circuit breaker bus bar assemblies in accordance with a fourth embodiment of the invention; 
     FIG. 39 is a perspective view of the circuit breaker bus bar assemblies of FIG  38 ; 
     FIGS. 40A-40D are exploded perspective views of the circuit breaker bus bar assemblies of FIG. 38; 
     FIG. 41 is a top plan view of the circuit breaker bus bar assemblies of FIG. 38; 
     FIG. 42 is a front elevational view of the circuit breaker bus bar assemblies of FIG. 38; and 
     FIG. 43 a right side elevational view of the circuit breaker bus bar assemblies of FIG.  38 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Illustrated in FIGS. 2-15 is a modular circuit breaker mounting system  37  comprising a circuit breaker bus bar assembly  38 A in accordance with the preferred embodiment of the invention. The circuit breaker bus bar assembly  38 A provides for modularity and pluggability of a set of circuit breakers  48  and their attendant contacts and comprises a circuit breaker panel  40  formed of an insulating material such as any known polymer or other electrically non-conducting material used in electrical applications. Circuit breaker panel  40  is substantially planar in shape and is provided with a plurality of holes  43 ,  45  (see FIGS. 3 and 6) extending therethrough and arranged in two rows along the length of slot  47  also formed in circuit breaker panel  40 . Slot  47  is optional and serves to provide access to signaling pins which may be provided in the pluggable circuit breakers  48  as discussed below. 
     Attached to the rear side of circuit breaker panel  40  is a common or ground bus bar  42  having a plurality of contact openings  44  in registration with holes  43  for pluggably receiving the corresponding post  46  of each of the circuit breakers  48  upon its passage through a hole  43 . Located within each of the contact openings  44  are electrical contact bands  50  (FIG. 4) for making electrical contact with post  46 . Ground bus bar  42  is of an electrically conducting material, such as for example copper, and serves to commonly connect posts  46  of the circuit breakers  48 , via the corresponding contact bands  50 , to electrical ground. Only shown partially in FIG. 2 is a second circuit breaker bus bar assembly  38 B, associated with a second set of circuit breakers, which can be attached to the first circuit breaker bus bar assembly  38 A to be in electrical communication therewith using coupling wire and assembly  52 . 
     Also attached to the rear side of circuit breaker panel  40  is electrically insulating housing  54  having a plurality of contact openings  56  in registration with holes  45  for receiving a plurality of crimped pin contacts  58 . Each pin contact  58  is provided with a pin portion  59  which is in electrical communication with the electrical conductor of a corresponding contact wire  60  of an electrical circuit (not shown). Located within each contact opening  56  is a retaining clip  62  for removably retaining each of the pin contacts  58 . Also located within contact openings  56  are electrical contact bands  64  and  66 . Electrical contact band  64  receives circuit breaker contact post  68 , which passes through a hole  45  in circuit breaker panel  40 , and electrical contact band  66  receives pin portion  59  of pin contact  58 . Each contact opening  56  also contains a cylindrical shroud, hood, or sleeve  70  of any electrically conductive material for housing each of the electrical contact bands  64  and  66 . Sleeve  70 , shown in FIGS. 9 and 10, provides both electrical and structural support for contact bands  64  and  66 , serving to complete the electrical connection between the contact bands and to increase their current load capacity while providing the necessary rigidity to support the pluggable nature of the connections of the circuit breakers  48  and wires  60 . Alternatively, connection between the posts  68  and corresponding pin contacts  58  can be effected using a unitary component, such as a thicker, elongated contact band disposed in contact openings  56 , dispensing with the need for sleeve  70 . 
     The electrical contact bands  50 ,  64  and  66  each have a “double crown” body, best illustrated in FIG. 4, wherein the generally cylindrical shape of the contact bands is provided with two constricted circumference regions  49 , with the resilient nature of the selected conductive material of the contact bands and the constricted circumference regions  49  operating to insure secure mechanical and electrical contact with the inserted posts  46  and  68  and pin portion  59 . One possible material for the contact bands is a beryllium-copper alloy. The contact band has first and second engagement portions  79  at its ends which serve to support the contact band in place within the associated contact opening (or sleeve  70  or socket portion  78  of pin contact  72 ), and to receive the pins or posts to be plugged thereinto. Interiorly of the engagement portions  79 , the structure of the contact band is in the form of resilient contact members or fingers  81  generally dimensioned to spring fit into the contact openings and around the pins to form a secure electrical and mechanical connection at least at the constricted circumference regions  49 . 
     Insulating housing  54  is formed of electrically non-conducting material, such as any suitable polymer for example, which maintains electrical isolation of each pin contact ( 58 )-contact post ( 68 )-contact wire ( 60 ) combination Locating the electrical contact bands  64  and  66  within insulated housing  54  and electrical contact bands  50  within conducting ground bus bar or common housing  42  provides pluggability of the circuit breaker  48  and each of the pin contacts  58  and attendant wires  60 , while eliminating the possibility of any damage from a crucial part of the electrical connection, namely the electrical contact bands. This embodiment of the invention provides for a pluggable, removable electrical connection for the crimped pin contact  58 . Likewise, there are pluggable connections for the posts  46  and  68  of the circuit breaker  48  for quick-release, quick-insert connections with substantially no risk of damage or loss to any of the electrical contact bands  50 ,  64  and  66 . 
     FIGS. 16-26 illustrate a second embodiment of a circuit breaker bus bar assembly in accordance with the present invention. The embodiment of FIGS. 16-26 provides the same pluggable modularity and protected electrical contacts as described with respect to the first embodiment. However, in the second embodiment, a different electrical coupling arrangement housed in a different insulated housing  154  is used. Insulated housing  154  is formed of any suitable electrically insulating material and is provided with contact openings  156  in registry with holes  45  of circuit breaker panel  40 . Disposed within contact openings  156  are pin contacts  72  which are each comprised of a socket portion  78  and a post portion  74 , both of which are made of an electrically conductive material and are in electrical contact with each other. Post portion  74  at least partially extends beyond the insulated housing  154  for pluggably mating with a socket contact  76  in electrical communication with the conductor of wire  60 . The socket portion  78  of each pin contact  72  houses therein an electrical contact band  64  for receiving the circuit breaker post  68  of the circuit breaker  48 . The socket contact  76  has a crimp barrel  80  attached to one side thereof for crimping onto wire  60 , and an electrical contact band (not shown) within a housing  82  for making electrical contact with the post portion  74  when the post portion is inserted into the socket contact  76 . In this manner an electrical path is established between the post  68  of circuit breaker  48  and the conductor in wire  60 , the electrical path relying on contact between post  68 , contact band  64 , socket portion  78  and post portion  74  of pin contact  72 , the contact band in socket contact  76  (not shown), and the conductor in wire  60 . The pin contact  72  of this type electrically and structurally supports electrical contact band  64  disposed in socket portion  78  thereof while providing a pluggable, snap-action, right angle attachment for the wire  60 . 
     FIGS. 25 and 26 show an arrangement in accordance with the second embodiment, but in use with a type of circuit breaker  148  having a signaling module  49  attached to one face thereof. Signaling module  49  is used to provide signals indicative of the status of each circuit breaker  148 —that is, whether the circuit breaker  148  has been tripped or not. To accommodate the signaling module  49 , signaling pins  51  protruding therefrom are passed through circuit breaker panel  40  via slot  47  provided therein. Mounted on the rear side of circuit breaker panel  40  is an auxiliary terminal connector  53  adapted to pluggably receive signaling pins  51  when the circuit breaker  148  is plugged into place. Auxiliary terminal connector  53  serves to bus signal from the circuit breakers  148  to one or more common locations, such as terminals  63 , to facilitate monitoring of circuit breaker status in the assembly. 
     FIGS. 27-37 illustrate an arrangement in accordance with a third embodiment of the present invention. The principle distinction of the third embodiment over the previous embodiments is that L-shaped brackets  84  having two threaded posts  86  extending outward therefrom are attached to the contact sleeves  170 , which are similar to sleeves  70  described previously and are disposed in contact openings  256  (FIGS. 34 and 35) of housing  254 . Each sleeve  170  is provided with a threaded portion  57  (FIG. 31) for threading into threaded holes  61  provided in brackets  84  for attachment thereto. Threaded portions  57  at least partially protrude from insulated housing  254  for mating with holes  61  of L-shaped brackets  84 , with a portion of each L-shaped bracket  84  extending outward from housing  254  to expose posts  86  adapted for use with conventional lug-type terminal connections. Circuit breaker panel  140  is shown with modified slots  147  which accommodate a pair of circuit breakers (not shown) in each slot. Power brackets  55 , shown in FIG. 27, may be provided for support and connection of the assembly. 
     FIGS. 38-43 illustrate an arrangement in accordance with a fourth embodiment of the present invention. As seen in FIGS. 38-43, a different form factor of the circuit breakers  248  is accommodated in the modular circuit breaker mounting system  137 . Referred to conventionally as level  4  type circuit breakers, circuit breakers  248  are designed to be earthquake proof and are generally smaller in size than those described above. Each circuit breaker  248  is provided with a pair of posts  146  and  168  (FIG. 40B) designed to plug into the associated circuit breaker bus bar assembly  138 . Two such assemblies,  138 A and  138 B are disclosed as comprising system  137 , but it is to be understood that other numbers of assemblies can be used. 
     Assembly  138 A comprises a circuit breaker panel  240  on which is mounted housing  142  formed of a conducting material, preferably copper, and serving to receive posts  146  of circuit breakers  248  and electrically connect these posts together. Housing  142  contains therein a plurality of contact openings  344  each housing therein, in the manner described above, a contact band (not shown) adapted to receive an associated post  146 . Housing  142  is connected electrically to conducting bracket  155  for common access to one of the positive or negative terminals of the main power circuit (not shown), or to ground. 
     Assembly  138 A also comprises a second, insulating housing  354  for receiving posts  168  of circuit breakers  248  and maintaining these in electrical isolation from each other. In a manner similar to that described above, housing  354  is provided with a plurality of contact openings  356  each containing therein a pair of contact bands (not shown) optionally housed in a suitable sleeve. The contact bands in the second housing respectively pluggably mate with a post  168  and a pin contact  158  of a wire of an associated circuit (not shown). 
     Optionally, a third housing  77  (see FIG.  40 C), formed of a conducting material, serves to receive the return wires (not shown) from the associated circuits and commonly couple these, via brackets  255 , to the other of the positive or negative terminals of the main power circuit (not shown), or to ground. 
     Assemblies  138 A and  138 B and the associated circuit breakers  248  are protected behind a pair of faceplates  71  and  73  and are connected thereto by brackets  75 . Access to circuit breakers  248 , for pluggable replacement thereof, is gained by removal of face plate  71 . 
     As mentioned above, all the embodiments described previously can be used in a modular fashion to accommodate any number N of circuit breakers. For example, FIG. 2 illustrates seven circuit breakers  48  being used in a circuit breaker bus bar assembly  38 A that can accommodate a set M of up to 12 circuit breakers with M≦N. The circuit breaker bus bar assembly  38 A can be provided in different sizes, for example, 4, 6, 10, 12 (as shown in FIG.  2 ), and 14, any of which can be combined with any other size circuit breaker bus bar assembly using coupling wires and assemblies  52 . As will be appreciated by the reading of the above disclosure, the present invention provides a circuit breaker and bus bar assembly that has a protected electrical contact band for providing improved performance and reliability in the design of circuit breakers and circuit breaker panel assemblies. Another principle advantage of the present invention is that a larger circuit panel and bus bar assembly than is currently needed can be incorporated into a design without having to utilize all of the circuit breakers and the attendant capital equipment cost in the early generation of the design, but subsequently the system can be upgraded by using the unused portions of the circuit panel and bus bar assembly. In other words, if initially only six circuit breakers are required for a design, but the possibility exists that the design may eventually require 12 circuit breakers, a 12-slot circuit breaker panel assembly in accordance with the present invention with only six circuit breakers plugged into the assembly can be used. Then, as more circuit breakers are required, the additional circuit breakers can be quickly plugged into the existing panel to provide a quick and easy upgrade. 
     The above are exemplary modes of carrying out the invention and are not intended to be limiting. It will be apparent to those skilled in the art that modifications thereto can be made without departure from the spirit and scope of the invention as set forth in the following claims.