Abstract:
A wiring junction block, e.g. for taillamp pigtails in a vehicle lighting system. The wiring junction block includes a body having an input end including a first set of electrical terminals for receiving electrical power from a vehicle wiring harness. The body also has an output end including a second set of electrical terminals for supplying the received electrical power to one or more vehicle lamps. The second set of terminals includes at least one group of two or more terminals that are electrically shorted to each other. The number of terminals in the first set is less than the number of terminals in the second set. A mounting feature is located on the body and is adapted to enable mounting of the body to a vehicle support structure, e.g. apertured panel. The input and output terminals may be electrically connected by stamped circuit traces or a printed circuit board.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to wiring harnesses and connectors, and more particularly to wiring harnesses and connectors of a type used in automobiles to route electrical power and signals throughout the vehicle. 
     DISCUSSION OF RELATED ART 
     A vehicle tail lamp assembly usually includes multiple lighting devices or lamps, and thus requires multiple power and ground wires for its operation. Typically, a vehicle wiring harness connector having multiple outputs directly provides those power and ground signals to the tail lamp assembly. The number of outputs from the wiring harness connector, however, is often times less than the number of inputs required by the multiple lighting devices of the tail lamp assembly. For instance, the wiring harness connector typically has a single ground output, even though that output must provide ground for each of the lighting devices of the assembly. In order to accommodate this unequal number of outputs and inputs, many vehicle lighting systems splice the single ground wire exiting the wiring harness connector into multiple wires, each of which is fed to a different lighting device. Similarly, the wiring harness connector usually provides a single tail lamp output although two or more lamps may be employed on each side of the vehicle to provide the tail lamp function. In order to send a power signal to each of the two tail lamps, that single output is spliced into two separate wires. An example of this type of prior art wiring arrangement is shown in  FIG. 1 . These splices can complicate assembly, as they may need to be manually installed and often require additional insulation and/or sealing precautions. 
     SUMMARY 
     The present invention is directed to an electrical wiring junction block that can be used for various electrical distribution purposes such as, for example, in a vehicle lighting system to connect power from a vehicle wiring harness to one or more vehicle lamps. The wiring junction block includes a body that may be formed of two or more parts. The body has an input end including a first set of electrical terminals for receiving electrical power from a vehicle wiring harness, and an output end including a second set of electrical terminals for supplying the received electrical power to one or more vehicle lamps. The second set of terminals includes at least one group of two or more terminals that are electrically shorted to each other. The number of terminals in the first set is less than the number of terminals in the second set. 
     In certain embodiments, a mounting feature is located on the body and is adapted to enable mounting of the body to a vehicle support structure, e.g. apertured panel. The input and output terminals may be electrically connected by stamped circuit traces or a printed circuit board. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will now be described by way of example with reference to the following drawings in which: 
         FIG. 1  is a wiring diagram exemplary of the prior art, showing wiring circuit splices; 
         FIG. 2  is a front view of an exemplary electrical wiring junction block in accordance with the present invention; 
         FIG. 3  and  FIG. 4  are side and rear views, respectively, of the wiring junction block of  FIG. 2 ; 
         FIG. 5  is a wiring diagram for a vehicle lighting assembly showing use of the wiring junction block of  FIG. 2 ; 
         FIG. 6  is a side view of an alternative embodiment of the wiring junction block of  FIG. 2 ; 
         FIG. 7  is a side view of another alternative embodiment of the wiring junction block of  FIG. 2 ; 
         FIG. 8  is a perspective view of yet another alternative embodiment of a wiring junction block in accordance with the present invention; and 
         FIG. 9  is a cross-sectional view of the wiring junction block of  FIG. 8 , taken along line  9 — 9 . 
     
    
    
     DETAILED DESCRIPTION 
     The present invention is directed to an electrical junction block that can be used for various electrical distribution purposes such as, for example, a vehicle lighting system junction block that is used to connect power from a vehicle wiring harness to one or more vehicle lamps. In this regard, it is noted that the embodiments of the invention discussed below are shown and described for illustrative purposes as they could be used for vehicle exterior lighting, and in particular rear vehicle lighting. However, these embodiments are exemplary only and the invention need not be limited to vehicle exterior lighting applications. 
     Typically, a vehicle electrical system will include a right rear lighting assembly, a left rear lighting assembly, a center high mount stop lamp, and perhaps other rear vehicle lighting such as one or more lamps for license plate illumination. The right and left rear lighting assemblies can each include brake, turn, tail, and backup illumination, and these four lighting functions are typically provided using at least two separate lamps in each assembly. The illustrated exemplary embodiments are directed to the use of the invention in conjunction with one such rear lighting assembly providing these four lighting functions. Separate junction blocks can be used for the other rear lighting functions, or all of the rear lighting wiring can be passed through a single junction block, as desired for a particular application. 
     Referring to  FIGS. 2–4 , there are seen front, side, and rear views, respectively, of an embodiment of the wiring junction block  10  of the present invention. The input end  12  of the junction block  10  includes six input terminals  14 ,  16 ,  18 ,  20 ,  22 ,  24  that are designed to connect to a conventional vehicle wiring harness (not shown) via a mating connector (not shown). As an example of the types of signals that may be transmitted by these terminals, although other variations are possible, input terminal  14  receives a ground signal, input terminal  16  receives a stop lamp signal, input terminal  18  receives a tail lamp signal, input terminal  20  receives a turn lamp signal (either right turn or left turn), input terminal  22  receives a backup lamp signal, and input terminal  24  receives a fog lamp signal. It is emphasized that these particular signals are intended to serve only as examples of the types of signals that may be transmitted via the junction block  10 . A greater or fewer number of signals could be provided for. As shown in the figures, the wiring junction block  10  includes a recessed surface  26  that is set back from a front surface  13  of input end  12 ; however, the junction block could be designed to have a single, flush surface extending across its entire front side. 
     The side view of  FIG. 3  shows internal electrical conductors  40  and  42  of junction block  10 . Conductor  40  is both connected to input terminal  20  at the input end  12  and to an output terminal  68 , as discussed below, at an output end  46 . In this particular embodiment, conductor  40  transmits a turn lamp signal from input terminal  20  to its respective output terminal  68 , which in turn connects to another mating connector (not shown) that sends the turn lamp signal to the appropriate lamp. Similarly, conductor  42  is connected to input terminal  18  at input end  12 . However, conductor  42  splits into two separate paths such that the single input terminal  18  feeds two separate output terminals  60 ,  61  at the output end  46 . Conductor  42  therefore accommodates one input terminal and two output terminals. As previously noted, input terminal  18  receives a tail lamp signal and this branching of conductor  42  to the two output terminals  60 ,  61  enables that signal to be routed to two separate lamps in the rear lighting assembly without the need for splicing of wiring. 
     Turning now to  FIG. 4 , the common connection (electrical shorting) of these two output terminals  60 ,  61  is represented diagrammatically by the wire connection shown in that figure at A. Similarly, the stop lamp signal provided to input terminal  16  is connected internally within the junction block  10  to two output terminals  66 ,  67  so that the signal can be routed to two separate lamps. Ground terminal  14  is connected within the junction block  10  to four output terminals  62 ,  63 ,  64 ,  65 , as shown, and this permits the junction block to be used with up to four different lamps to implement the stop, turn, tail, backup, and fog lamp functions that can be signaled via the input terminals  16 ,  18 ,  20 ,  22 ,  24 . The remaining output terminals  68 ,  70 ,  72  are each connected individually to the input terminals  20 ,  22 ,  24 , respectively, by separate isolated conductors, such as conductor  40  shown in  FIG. 3 . Junction block  10  thus has six input terminals (see  FIG. 2 ) and eleven output terminals (see  FIG. 4 ). As previously stated, the particular signals being transmitted, the number of input terminals, the number of output terminals, etc., can differ from the particular exemplary embodiment shown, as desired. This embodiment has been provided to illustrate that at least one internal conductor may branch into multiple channels, while another may remain a single channel as they extend through the junction block  10 . 
     The junction block  10  is formed from a plastic body  30  housing the electrical terminals  14 ,  16 ,  18 ,  20 ,  22 ,  24  and  60 ,  62 ,  63 ,  64 ,  65 ,  66 ,  67 ,  68 ,  70 ,  72 . For example, the junction block body  30  can be a single unitary plastic component injection molded about the terminals and internal conductors. Alternatively, the junction block  10  can comprise a collection of separate pieces assembled together. 
     As shown, the input terminals can be metal blade terminals that mate with suitable socket or clip terminals from a wiring harness connector. The output terminals can be socket terminals that receive correspondingly shaped plug terminals from a lamp wiring harness connector that is used to connect to the various lamps in the rear lighting assembly. Of course, terminals having other shapes or of other connecting configurations can be used. Furthermore, the terminals at either the input end  12 , or output end  46 , or both, can be hardwired to the vehicle and lamp wiring harnesses. 
     In order to increase the versatility of the junction block, that is, in order to make the junction block compatible with a wide variety of wiring harness connectors and vehicle applications, the junction block  10  can include input and output terminals for each of the potential signals required for the different applications. Thereafter, for any particular application, any unneeded input and output terminals can be simply left unused, or be sealed off with molded plugs. For example, the fog lamp signal terminals  24  and  72  can be provided to accommodate European platforms even though no rear fog lamp is normally used in the United States. Then, for the U.S. platforms, these terminals are simply left unused. Thus, the junction block  10  provides a single common (universal) junction block that may be utilized in a variety of vehicle platforms. 
     Referring now to  FIG. 5 , the output end  46  of the junction block  10  of  FIGS. 2–4  is shown. The rear lighting assembly  80  is an example of the type of lighting assembly that may be used with the junction block  10 . This particular lighting assembly includes three lighting devices—a backup lamp  82 , a stop/tail lamp  84 , and a turn/tail lamp  86 —and these lighting devices are shown from their rear side wherein only the integrated socket/connectors are shown mounted in a conventional manner to a common vehicle panel  88 . These sockets each support a standard incandescent lamp (not shown) such as a GT-8 model available from the Wagner Lighting division of Federal-Mogul Corporation. A socket design such as that shown in U.S. Pat. No. 5,035,643 to Forish et al. can be used, and the complete disclosure of that patent is hereby incorporated by reference. Suitable sockets are available from the Zanxx division of Federal-Mogul Corporation. 
     According to this particular embodiment, backup lamp  82  includes a single filament that is connected to output terminal  70  for receiving a backup lamp signal and to output terminal  64  for receiving a ground signal connection. Stop/tail lamp  84  includes two filaments. The first, or major, filament is connected to output terminal  66  such that it receives the stop lamp signal. The second, or minor, filament is connected to output terminal  60  such that it receives a tail lamp signal. Lamp  84  uses a single ground wire to connect with output terminal  63 , such that a ground connection is provided for both filaments. 
     Turn/tail lamp  86  also includes two filaments, one of which is a first, or major, filament connected to output terminal  68  for receiving a turn lamp signal. A second, or minor, filament is connected to the other tail lamp output terminal  61 . As with the other lamps, the turn/tail lamp  86  has a ground wire, which is connected to output terminal  65 . 
     As indicated in  FIG. 4 , several of the junction block output terminals are not connected to a lighting device. Output terminal  72 , which carries the fog lamp signal, output terminal  62  which is one of the four output terminals connected to ground, and output terminal  67 , which carries the stop lamp signal, are all unused by this exemplary rear lighting assembly. Thus, these output terminals can be sealed off with a molded plug. If this particular application required any of these unused terminals/signals, they would simply be connected to the appropriate lighting device. In this manner, the junction block of the present invention can accommodate a wide variety of applications potentially having various input and output terminal configurations. 
     With reference now to  FIG. 6 , there is shown an embodiment in which a junction block  100  includes an integral mounting feature so that the junction block  100  can be mounted in an aperture  102  of a panel or other vehicle support structure  104 . The junction block  100  thereby provides the dual function of splicing common connections (such as the tail lamp and ground connections) and acting as a feed-through of the electrical power through a body panel. Junction block  100  includes an input end  106  that mates with a complementary connector  108 , which can be provided as a part of the vehicle wiring harness. 
     The junction block  100  also includes an output end  110  that, in this embodiment, is hardwired to individual sockets for the various lamps in the lighting assembly. The particular mounting feature shown in  FIG. 6  is a twist-lock connector  112  that includes locking lugs  114  such that the twist-lock connector  112  can be inserted into the aperture  102  and then be rotated counter-clockwise so that the locking lugs  114  secure the junction block  100  in place on the panel  104 , thereby securely fastening the junction block  100  to the panel  104 . The locking lugs  114  can either interact with the surface of the panel itself, as shown, or engage complementary mounting features designed into the panel. 
     An elastomeric O-ring  116  or other suitable perimeter seal can be provided to prevent moisture from passing from one side of the panel to the other. As will be appreciated by those skilled in the art, junction block  100  permits wires to be coupled from the vehicle wiring harness connector  108 , through the opening  102  in the panel  104 , and into the necessary number of connections for the rear lighting assembly, without the need for feeding wires through the opening and then manually terminating them in a connector. In this embodiment, the wires extending from the output end  110  are hardwired. However, socket or plug terminals could be used to connect to another connector, as in  FIGS. 2–5 . The other aspects of junction block  100  (e.g., internal connections and plastic body construction) can be the same as described above in connection with  FIGS. 2–5 . 
       FIGS. 8 and 9  show an alternative embodiment of a junction block  100  in accordance with the present invention. Like the junction block  100  of  FIG. 6 , the junction block  100  of  FIGS. 8 and 9  includes an integral mounting feature, namely twist-lock connector  112  that includes locking lugs  114  such that the twist-lock connector  112  can be inserted into an aperture (not shown) and rotated counter-clockwise so that the locking lugs  114  secure the junction block  100  in place on a panel (not shown), thereby securely fastening the junction block  100  to the panel as discussed above with reference to  FIG. 6 . Additionally, the junction block  100  includes an elastomeric or other suitable perimeter seal  116  to prevent moisture from passing from one side of the panel to the other. The junction block  100  includes an input end  106  for mating with a complementary connector (not shown), which can be provided as part of a vehicle wiring harness. The junction block  100  also includes an output end  110  that, in this embodiment, is configured to receive a connector from a lighting assembly, etc. Accordingly, the junction block  100  provides a dual function of splicing common connections and acting as a feed-through of electrical power through a body panel as discussed above with reference to  FIG. 6 . 
     In the embodiment of  FIGS. 8 and 9 , however, pin type terminals  16 ,  18 ,  20 ,  22  are provided on the input end  106 , as well as on the output end  110  as shown at  60 ,  61 ,  68 . In the example of  FIGS. 8 and 9 , the input and output terminals are electrically connected as described above with reference to  FIGS. 2–5 . However, in this embodiment, electrical circuitry  45  is provided to electrically connect the input and output terminals, as desired. Specifically, in the example of  FIGS. 8 and 9 , stamped copper traces, or the like,  45  are provided to electrically connect the input and output terminal pins, as desired. Accordingly, the electrical circuitry  45  replaces, or implements, conductors  40 ,  42 , etc. In an alternative embodiment, a conventional-type printed circuit board provides the electrical circuitry to electrically interconnect the input and output terminals. It should be noted that resistors, diodes and other electrical/electronic components may be integrated into the circuitry interconnecting the input and output terminals, as desired. Any suitable circuitry can be provided as will be appreciated by those skilled in the art. In the exemplary embodiment of  FIGS. 8 and 9  the junction block  100  is formed from two mechanically joined halves  100   a ,  100   b  with the desired circuitry disposed therebetween. Alternatively, the entire junction block  100  may be formed as a unit around the circuitry and pins using a conventional insert molding technique. 
     It will thus be apparent that there has been provided in accordance with the present invention an electrical wiring junction block for use with vehicle lighting systems that achieves the aims and advantages specified herein. It will of course be understood that the foregoing description is of preferred exemplary embodiments of the invention and that the invention is not limited to the specific embodiments shown. Various changes and other modifications will become apparent to those skilled in the art. All such variations and modifications are intended to come within the scope of the invention.