Abstract:
An identification light bar as required by 49 C.F.R. Section 571.108 for vehicles over eighty inches in width is disclosed. The light bar comprises an elongate body having a center optic, left and right distal optics, and left and right light pipes which connect the respective distal optics to the center optic. Each optic is covered by a respective lens cap. A single LED is connected to the body in alignment with the center optic. The center optic receives light emitted by the LED and divides the light such that a first portion thereof is emitted from the light bar through the center lens cap, a second portion thereof is transmitted along the left light pipe and emitted through the left lens cap, and a third portion thereof is transmitted along the right light pipe and emitted through the right lens cap.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an identification light bar as required by 49 C.F.R. §571.108 for vehicles over 80 inches in width, and in particular to such an identification light bar having three lenses illuminated by a single light source, such as a single light emitting diode. 
     2. Description of the Related Art 
     Section 571.108 of the Code of Federal Regulations requires that all multipurpose passenger vehicles, trucks, trailers and buses having an overall width of over 80 inches be equipped with a set of three red identification lamps which are mounted on the rear of the vehicle in order to alert other motorists to the presence of a wide vehicle. The lamps are to be mounted as close as practicable to the top of the vehicle, at the same height, and as close as practicable to the centerline of the vehicle. The centers of the lamps must be not less than six or more than 12 inches apart. Multipurpose passenger vehicles, trucks and buses having an overall width of over 80 inches must also be equipped with a similar set of amber identification lamps on the front of the vehicle. 
     Traditionally, these sets of identification lights have been illuminated by incandescent bulbs, with one or more of the bulbs being mounted in each of the three lamps. Incandescent bulbs, however, are prone to failure, and the bulbs must be inspected and replaced regularly. In recent years, lighting manufacturers have begun to substitute light emitting diodes (LEDs) for the incandescent bulbs used in vehicle lighting. LEDs have a rated life of 100,000 hours, which is far superior to that of an incandescent bulb. 
     LEDs can be used in an identification light system by placing one or more of the LEDs in each of three lamps. The assignee of the present invention produces an identification light bar using LEDs in this manner, the Peterson Manufacturing Co. Piranha® LED Model 160-3R. Vehicle lamps incorporating multiple LED light sources can be relatively expensive, however and require multiple electrical connections. 
     There would be distinct advantages to an identification lamp system wherein a single LED was used to illuminate all three of the identification lamps. Such a system would be less expensive to produce, and would draw less current than a multiple LED system. Lower current draw would allow the use of lighter gauge wiring, further lowering the cost of using such a system. Furthermore, use of a single light source reduces the number of electrical connections required to power the identification light system. Fewer connections means both simpler installation and fewer potential failure points. 
     It has previously been known to pipe light from a single source for use as vehicle marker lighting. U.S. Pat. No. 4,947,293 to Johnson, et al. discloses a vehicle clearance light system wherein light from a single source is piped through a light conducting strip clad in a translucent material having a different index of refraction from the core material. The result is a continuous strip of lighted material around the top of a vehicle which can serve as clearance lighting. Note that as shown in FIG. 2, this device is intended as a supplement to the existing lighting required by vehicle regulations and not as replacement therefor. The continuous strip of light produced by this system is incapable of serving the mandated identification function, since the regulation requires three distinct lamps spaced a specified distance apart. 
     U.S. Pat. No. 5,122,933 to Johnson discloses a combination clearance light and message system for trucks. In this system, a pair of fiber-optic cables pipe light from a single high intensity source around the perimeter of a truck trailer. The cables are encased within an enclosure having a translucent face plate. The face plate can be provided with a graphic message such as an advertising slogan which is illuminated by light from the fiber optic cables. It is also specified that a portion of the enclosure may be colored to provide the legally required clearance lighting function. It should be noted that this system utilizes a high intensity light source, such as a quartz halogen lamp, to provide illumination to the entire length of a semi trailer. A high intensity system of this kind is not suitable to the more limited task of serving the federally mandated identification light function for wide vehicles. 
     In a related product, the Assignee of the present invention has for more than one year manufactured a round, two inch diameter, combination clearance and side marker light, the Peterson Manufacturing Co. Piranha® LED Model 165. This light is designed to function as both a clearance light and a side marker light when mounted on a forty five degree angle. The lamp includes a center LED which is focused onto a portion of the lens having surfaces inclined at a 45 degree angle which act as a prism to deflect portions of the light from the center LED in respective lateral directions, allowing the lamp to be clearly seen from the sides. 
     SUMMARY OF THE INVENTION 
     The present invention comprises a light bar for a vehicle having three lenses illuminated by a single light source, such as an LED. The lenses may be spaced apart and colored so as to comply with 49 C.F.R. §571.108 as identification lamps for vehicles over 80 inches in width. The light bar includes an elongated, transparent body having a center optic, a left distal optic, a right distal optic, a left light pipe extending outwardly from the center optic to the left distal optic, and a right light pipe extending outwardly from the center optic to the right distal optic. Each of the optics is covered by a respective lens. 
     The light source is aligned with the center optic such that the center optic receives light emitted by the light source and divides the light-into three portions of generally equal intensity. A first portion of the light is emitted from the light bar through the lens covering the center optic, a second portion is transmitted along the left light pipe and emitted from the light bar through the lens covering the left distal optic, and a third portion is transmitted along the right light pipe and emitted from the light bar through the lens covering the right distal optic. 
     Each of the lenses includes a tubular sidewall and an end wall closing one end of the tubular sidewall. The light bar is mounted on the interior of a front or rear wall of the vehicle with the tubular sidewalls of the lenses extending through respective holes in the vehicle wall. The holes in the vehicle wall are sealed by respective elastomeric gaskets such that only the end walls of the lenses are visible from the exterior of the vehicle. When mounted in this manner, light emitting from the lenses will be seen from outside the vehicle and any light leaking from other parts of the light bar will not. 
     The tubular sidewall of each lens may include an annular ridge which extends outwardly therefrom, and each grommet may include an internal annular groove sized and shaped to receive the annular ridge of the respective lens. If the annular ridges are formed with a tapered front edge and a square rear edge, the tapered front edges will allow the lenses to be easily inserted into the respective grommets whereas the square rear edges will inhibit the lenses from being pulled out of the grommets, thereby securing the light bar to the vehicle. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a light bar embodying the present invention. 
     FIG. 2 is a schematic diagram of the electronic components of the light bar. 
     FIG. 3 is an enlarged cross-sectional view of the central portion of the light bar taken generally along line  3 — 3  in FIG.  1 . 
     FIG. 4 is an enlarged, fragmentary rear view of the body of the light bar showing the center optic thereof. 
     FIG. 5 is an enlarged, fragmentary front view of the body of the light bar showing the center optic thereof. 
     FIG. 6 is an enlarged, fragmentary cross-sectional view of the center optic taken generally along line  6 — 6  in FIG.  5  and showing reflection of light down opposing light pipes. 
     FIG. 7 is an enlarged, fragmentary, cross-sectional view of the center optic taken generally along line  7 — 7  in FIG.  5  and showing transmission of light outwardly from the center optic. 
     FIG. 8 is an enlarged, fragmentary, cross-sectional view of the center optic taken generally along line  8 — 8  in FIG.  5  and showing transmission of light outwardly from the center optic. 
     FIG. 9 is an enlarged, fragmentary front view of the body of the light bar showing the left distal portion thereof. 
     FIG. 10 is an enlarged, fragmentary cross-sectional view of the body of the light bar showing the left distal portion thereof, taken generally along line  9 — 9  in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
     Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, the words “upwardly,” “downwardly,” “rightwardly,” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the embodiment being described and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof and words of a similar import. 
     Referring to the drawings in more detail, and in particular to FIG. 1, the reference number  1  designates an identification light bar embodying the present invention. The light bar  1  generally comprises an elongate transparent body  3 , a circuit board  5  with its attached electronic components including a single light-emitting diode (LED)  7 , a center lens  9 , and two distal lenses  11 . Lead wires  13  are provided for connecting the circuit board  5  to the electrical system of a vehicle (not shown). 
     In addition to the LED  7 , the circuit board  5  includes the electronic components required to illuminate the LED  7 , the circuit diagram for which is shown in FIG.  2 . Male blade terminals  15  are provided on the board  5  for connecting the board to female flag terminals  16  on the lead wires  13  (see FIG.  1 ). Referring again to FIG. 2, the terminals  15  are connected to a full wave rectifier bridge  17  comprising four diodes  19 . The rectifier bridge  17  insures that the proper polarity is provided to the LED  7  irrespective of how the lead wires  13  are connected to the vehicle wiring system. From the rectifier bridge  17 , current flows through a 91 ohm first resistor  21  to a first junction  23 . From the first junction  21 , current flows through a 68 ohm second resistor  25  to the anode of the LED  7 . The cathode of the LED  7  is connected back to the rectifier bridge  17  through a second junction  27 . A unidirectional transient voltage suppressor  29  is connected in parallel to the second resistor  25  and LED  7  between junctions  23  and  27 . The transient voltage suppressor  29  serves to protect the LED  7  from voltage surges. 
     Referring again to FIG. 1, light produced by the single LED  7  is divided and transmitted through the body  3  so as to be emitted through the center lens  9  and two distal lenses  11  at approximately equal intensities. The lenses  9  and  11  thereby serve the function of the three identification lamps required by Section 571.108 of the Code of Federal Regulations. If the light bar  1  is intended for mounting on the rear of a vehicle, the lenses  9  and  11  will be red in color, whereas if the light bar  1  is intended for mounting on the front of the vehicle, the lenses  9  and  11  would be amber in color. Alternatively, the lenses  9  and  11  could be clear with either a red or amber LED  7  used, depending upon the intended mounting location of the light bar  1 . 
     The body  3  is preferably formed as a unitary piece which is molded of clear lens grade acrylic. A polycarbonate material could be used in place of acrylic, however acrylic is less likely to bend and transmits light with less loss. The body  3  generally includes a central chamber  31  and a pair of light pipes  33  which extend outwardly therefrom. Each light pipe  33  has a distal end  35  which includes a respective distal lens mounting base  37  which serves as a mounting location for a respective one of the distal lenses  11 . 
     Referring to FIG. 3, the central chamber  31  is generally in the form of a rectangular box having a top wall  39  (see FIG.  1 ), a bottom wall  41  and opposed sidewalls  43 . The front of the central chamber  13  is enclosed by a front wall  45  which includes a center optic  47  to be described in detail later. The front wall  45  has an inner surface  49 , an outer surface  51 , and further includes a center lens mounting base  53  formed on the outer surface  51  which serves as an attachment point for the center lens  9 . The mounting base  53  is centered over the center optic  47 . The back of the chamber  31  is open and provides a mounting location for the circuit board  5 . 
     When installed in the chamber  31 , the circuit board  5  is seated against an inwardly extending ledge  55  formed on the chamber walls  39 ,  41  and  43 . An ABS backing plate  57  is inserted into the chamber  31  behind the circuit board  5  to hold the board  5  in position. The backing plate  57  snaps into position by engaging protrusions  59  formed on the chamber top wall  39  and bottom wall  41 . An opening  61  in the backing plate  57  is provided to allow the lead wires  13  to pass therethrough. The backing plate  57  further includes a wire retainer  63  which holds the lead wires  13  in position. After the circuit board  5 , lead wires  13  and backing plate  57  are installed in the chamber  31 , curable urethane sealant  65  is poured into the rear of the chamber  31 . Once cured, the sealant  65  prevents moisture from entering the chamber  31 . With the circuit board  5  thus installed in the chamber  31 , the LED  7  mounted thereon is centered behind the center optic  47  in closely spaced relation thereto such that light emitted by the LED  7  is directed onto the center optic  47 . 
     Referring to FIG. 4, the center optic  47  includes a generally rectangular projection  67  which extends rearwardly from the inner surface  49  of the front wall  45  and into the chamber  31 . The projection  67  is centered on the wall  45  and includes a pair of longitudinal edges  69  which are each spaced inwardly from a respective one of the top wall  39  and the bottom wall  41 . The projection  67  also includes a pair of transverse edges  71  which are spaced inwardly from the respective sidewalls  43 . A pair of inclined planes  73  are formed on the inner surface  49  between the transverse edges  71  of the projection  67  and the respective sidewalls  43 . The planes  73  slope rearwardly from a point on the inner surface  49  which is spaced inwardly from the respective sidewall  43  to a point approximately midway up the respective transverse edge  71 . 
     Referring to FIG. 5, the center optic  47  further includes a cavity  75  which extends inwardly from the outer surface  51  of the front wall  45 , through the front wall  45 , and into the projection  67 . The cavity  75  is defined by a pair of sidewalls  77 , opposing top and bottom walls  81 , and a back wall  83 . The sidewalls  77  are inwardly curved such that the cavity  75  has a generally hourglass shape when viewed from the front. The sidewalls  77  are also inwardly sloped from front to rear in a convex curve selected to direct that portion of the light from the LED  7  which is incident on one of the sidewalls  77  down the respective light pipe  33 , as shown in FIG.  6 . The back wall  83  is only visible from the front of the body  3  as a pair of small triangular portions at the top and bottom of the cavity  75 . 
     A bridge wall  85 , which forms a part of the center optic  47 , is formed across the cavity  75  along the longitudinal centerline of the body  3  so as to divide the cavity  75  into upper and lower portions  75   a  and  75   b , respectively. The bridge wall  85  is aligned with the LED  7  and has a thickness which is sufficient for the wall  85  to form a light conduit which allows a portion of the light from the LED  7  to pass directly therethrough, as shown in FIGS. 7 and 8. 
     The center lens mounting base  53  surrounds the cavity  75  and comprises a circular platform upon which the center lens  9  is mounted. The base  53  includes an annular ridge  87  which acts to locate the lens  9 . The ridge  87  includes a keyway  89  which accepts an aligning tab  91  on the lens  9  (see FIG.  1 ). 
     Referring again to FIG. 3, the light pipes  33  each extend outwardly from a respective one of the sidewalls  43  of the central chamber  31  in respective opposing longitudinal directions. The light pipes  33  each have a generally C-shaped cross-section and include a front wall  93  and opposed top and bottom webs  95 . The front walls  93  are generally the same thickness as the chamber front wall  45  and are aligned in register with the chamber front wall  45  so that the front walls  93  generally form extensions of the chamber front wall  45 . The webs  95  serve both as structural strengthening members and as additional light transmission paths. Fillets  97  formed at the junctions between the webs  95  and chamber sidewalls  43  add additional strength to the light pipes  33 . 
     As best seen in FIG. 9, the distal lens mounting bases  37  are each integrally formed with one of the light pipes  33  at the distal end  35  thereof. Each distal lens mounting base  37  is in the form of a circular plate, the outer face of which is oriented generally in alignment with the front wall  93  of the respective light pipe  33 . Each distal lens mounting base  37  extends outwardly past the distal end  35  of the respective light pipe  33  such that the distal end  35  is oriented in the center of the respective distal lens mounting base  37 . Like the center lens mounting base  53 , the distal lens mounting bases  37  each include an annular ridge  87  which acts to locate the respective lens  11 . The ridges  87  each include a keyway  89  which accepts an aligning tab  91  on the respective lens  11 . 
     Referring to FIG. 10, the distal ends  35  of the light pipes  33  further include a distal optic  99  which serves to refract light transmitted along the respective light pipe  33  and direct it toward the respective distal lens  11 . Each distal optic  99  includes a distal end surface  101  of the respective light pipe  33  which is canted inwardly from front to back at a roughly forty-five degree angle. A relief  103  is formed in the rear of each mounting base  37  such that the respective end surface  101  extends substantially the thickness of the front wall  93  of the respective light pipe  33 . Each distal optic  99  further includes a circular pad  105  formed on the front surface of the respective mounting base  37 . Each pad  105  has a plurality of vertical flutes  107  formed thereon. 
     As shown in FIGS. 1 and 3, each of the lenses  9  and  11  includes an annular mounting flange  109  which is sonic welded to the respective lens mounting base  37  or  53 . A tubular sidewall  111  extends outwardly from the annular mounting flange  109  to a front plate  113  which encloses the front of the respective lens  7  or  9 . Each front plate  113  includes a lens optic  115  comprising a textured inner lens surface having both horizontal and vertical striations. The aligning tab  91  of each lens  9  or  11  extends outwardly from the respective mounting flange  109  and engages the respective keyway  89  to align the striations in the proper orientation. An outwardly extending annular ridge  117  is formed around each lens sidewall  111 . Each flange  117  has a square rear edge  119  and a tapered front edge  121  (see FIG.  1 ). 
     As best seen in FIG. 3, the fight bar  1  is mounted inside a front or rear wall  123  of a vehicle. Three mounting holes  125  are cut through the wall  123  and spaced an appropriate distance apart to align with the lenses  9  and  11  of the light bar  1 . Rubber grommets  127  having an inside diameter matching the diameter of the lens tubular sidewalls  111  are inserted into the mounting holes  125 . Each grommet  127  includes a circumferential annular groove  128  which is sized to accept an annular portion of the vehicle wall  123  which surrounds the mounting a respective one of the mounting holes  125 . Each grommet  127  also has an internal annular groove  129  sized and shaped to receive the ridge  117  on the respective lens  7  or  9 . The grommets  127  are first placed in the mounting holes  125  with the grooves  128  retainably engaging the wall  123 . The lenses  9  and  11  of the light bar  1  are then inserted into the grommets  127  from the inside of the vehicle. The tapered front edges  121  of the ridges  117  allow the ridges  117  to snap into the grooves  129  in the grommets  127 , whereas the square rear edges  119  engage the grooves  129  to prevent the lenses  9  and  11  from being easily dislodged from the grommets  127 . 
     With the light bar  1  thus installed, only the front plates  113  of the lenses  9  and  11  communicate with the exterior of the vehicle and only light emitted through the front plates  113  can be seen from outside the vehicle. Any stray light which escapes through other parts of the light bar  1  will not be seen from the exterior of the vehicle. The grommets  127  form a weather resistant seal which prevents moisture from entering the vehicle through the mounting holes  125 . 
     In use, light emitted by the LED  7  is directed onto the center optic  47  which divides the light into three portions. A first portion of the light passes directly through the bridge wall  85  and is emitted through the center lens  9 . A second portion is reflected internally off of one of the cavity sidewalls  77  and thereby turned ninety degrees so as to be directed down the respective light pipe  33  to the respective distal optic  99 . A third portion is reflected internally off of the other cavity sidewall  77  and thereby turned ninety degrees so as to be directed down the second light pipe  33  to the respective distal optic  99 . The second and third portions are each reflected internally off of the respective distal end surface  101  of the respective light pipe  33  and again turned ninety degrees so as to be emitted through the respective distal lens  11 . The lens optics  115  and flutes  107  combine to disperse the light in a desired photometric pattern. The bridge wall  85  and sidewalls  77  of the center optic  47  are sized such that the first, second, and third portions of the light are emitted at substantially equal intensity. 
     It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown.