Abstract:
A disclosed bus stop arm includes an extendable arm for protruding from a bus and including signage instructing motorists to stop, a socket in the extendable arm for receiving a lamp, and a lamp having a connector configured to be received in the socket. The lamp includes at least two light emitting diodes, the light emitting diodes projecting light in substantially opposite primary directions. A disclosed lamp for a bus stop arm includes a connector configured to fit in a lamp socket on a bus stop arm, and at least two light emitting diodes. The light emitting diodes project light in substantially opposite primary directions.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
       [0001]    The present application claims priority to U.S. Priority Provisional Application No. 60/894,105 filed Mar. 9, 2007, and the aforementioned application is hereby incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    The present application relates generally to the field of lamps. More specifically, the disclosure relates to lamps using light emitting diode (LED) technology in a stop arm for a school bus. 
         [0003]    A school bus often will have a stop arm that extends from the side of the bus to emphasize that motorists must stop at the critical point of loading/unloading children. Existing school bus stop arms utilize incandescent, LED and strobe technologies in various ways to help eliminate the dangerous and illegal passing of the school bus during loading/unloading. 
         [0004]    A common product utilizes incandescent lights on both the upper and lower half of the stop arm, which alternately illuminate in an upper/lower/upper/lower sequence. The alternating sequence is controlled by an onboard flasher assembly unit (a product of the bus body itself). As more and more emergency vehicles move toward rapid flash technology, motorists become de-sensitized to buses with the older steady state, incandescent lamp technology. 
         [0005]    Strobe lamp technology uses the same upper/lower flash pattern, only with a more rapid flash pattern characteristic of strobes. This technology, however, has disadvantages. The strobe unit utilizes a power pack and flasher assembly found within the stop arm itself. Thus, to convert an existing incandescent stop arm to strobe is a costly and a time consuming task. Moreover, strobe lamp technology uses expensive Xenon bulbs, which must be replaced often. 
         [0006]    LED bulb technology generally work in two different manners. In a first type of LED stop arm, individual LEDs actually spell out the word “STOP” and utilize the buses internal flasher to activate and deactivate the LEDs to yield an on/off pattern. In a second type of LED stop arm, the lights are rapid flash LED modules. These encapsulated units utilize multiple LEDs mounted on a PCB and are self contained along with a lens to create a “sealed module”. To convert an existing incandescent stop arm to this type of LED, a technician must remove internal components and replace existing wires, resulting in a time consuming and costly effort. 
       SUMMARY 
       [0007]    According to one embodiment of the present invention, a bus stop arm comprises an extendable arm for protruding from a bus and including signage instructing motorists to stop. The bus stop arm further comprises a socket in the extendable arm for receiving a lamp, and a lamp having a connector configured to be received in the socket. The lamp includes at least two light emitting diodes, the light emitting diodes projecting light in substantially opposite primary directions. 
         [0008]    According to another embodiment of the present invention, a lamp for a bus stop arm comprises a connector configured to fit in a lamp socket on a bus stop arm, and at least two light emitting diodes. The light emitting diodes project light in substantially opposite primary directions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The features, aspects, and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below. 
           [0010]      FIG. 1  is a front view of an LED lamp according to one exemplary embodiment, coupled to an existing incandescent bulb socket in a school bus stop arm. 
           [0011]      FIG. 2  is a side perspective view of the LED lamp of  FIG. 1  removed from the incandescent bulb socket, showing the interface. 
           [0012]      FIG. 3  is a side perspective view of the incandescent bulb socket in the school bus stop arm of  FIG. 1 . 
           [0013]      FIG. 4  is a schematic diagram of the LED lamp of  FIG. 1 . 
           [0014]      FIG. 5  is a more detailed schematic diagram of the LED lamp of  FIG. 1 . 
           [0015]      FIG. 6  is a front view of a base of the LED lamp of  FIG. 1 . 
           [0016]      FIG. 7  is a rear view of a school bus stop arm with the LED lamp of  FIG. 1  mounted to a top socket and with a lens affixed over the bottom socket, which also contains an LED lamp. 
           [0017]      FIG. 8  is a cross-sectional view taken along line  8 - 8  in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Referring to  FIG. 1 , an embodiment of a LED lamp  10  according to the present invention is shown. According to one preferred embodiment, the LED lamp  10  is configured to be used with a conventional stop arm  12  for a school bus, such as the stop arm  12  shown in  FIG. 7 . The lamp  10  can be configured to be a direct replacement for an existing incandescent bulb on the stop arm  12 . The lamp  10  can be configured to mount in the same lamp socket  14  (as shown in  FIG. 3 ) as the incandescent bulb it replaces, and to be small enough to be received by the existing space  32 A in the stop arm configured for the incandescent bulb. At the top of  FIG. 7 , a partially transparent outer capsule or lens  31  has been removed from the stop arm  12  so that the existing space  32 A can be seen. However, the lamp  10  is preferably configured so that in operation it will be covered with the lens  31 , as shown at the bottom of  FIG. 7 . 
         [0019]    The lamp  10  preferably includes two electrical contacts  33  and  34  on a connector or base  20 , a printed circuit board (PCB)  22  connected to the base  20 , circuit components  30 , and two light emitting diodes (LEDs)  24  coupled to opposite sides of the PCB  22 . 
         [0020]    As shown in  FIG. 2  and according to a preferred embodiment, the base  20  can be a two-pin bayonet connector (e.g., a SMC 1156DC (incandescent stop arm bulb)), which is a commonly used base in automotive applications. In particular, such a base is often used on incandescent bulbs mounted in school bus stop arms. The base  20  can include two outwardly extending pins  21  that extend outward from a center region of the base and engage corresponding slots  16  in the socket  14  of the school bus stop arm  12  to mechanically couple the lamp  10  to the socket  14 . The interaction of the pins  21  and slots  16  also positions the lamp  10  in a proper orientation relative to the stop arm. The base  20  further includes the two electrical contacts  33  and  34 . The electrical contacts  33  and  34  are provided on the bottom of the base  20  and interface with corresponding contacts within the socket  14  to electrically couple the lamp  10  to the stop arm  12 . The base could, however, be other structures such as a screw base or any other lamp base that suitably physically and electrically couples the lamp to the socket. Using an existing lamp socket facilitates the retrofitting of existing incandescent systems with LED bulbs without having to add or replace other electric components. 
         [0021]    The PCB  22  preferably is physically coupled to the base  20  and electrically coupled to the electrical contacts  33  and  34 . The primary plane of the PCB  22  preferably is oriented generally parallel or coincident to the primary plane of the stop arm  12  when the lamp  10  is installed in the lamp socket  14 . In other words, as shown in  FIG. 8 , the PCB  22  and the face of the stop arm  12  preferably are oriented in the same direction. Two LEDs  24  can be coupled to the PCB  22  on opposite sides of the PCB  22  and shine light primarily outward from the PCB  22  on both sides of the stop arm  12 , i.e., in the primary directions shown by the arrows in  FIG. 8 , though light may be emitted in other, secondary directions. By using the base  20  having the pins  21  and by creating a predetermined spatial relationship between the pins  21  and the PCB  22 , the lamp  10  can be configured such that the PCB  22  and LEDs  24  will assume the desired position relative to the stop arm  12  when the lamp  10  is inserted in the lamp socket  14 . In this manner, each of the two LEDs  24  can project light in a primary direction substantially perpendicular to a corresponding surface on a signage area of the stop arm  12 .  FIG. 7  shows one such surface of signage area on the stop arm  12 , i.e., the area that states “STOP,” with a corresponding and opposing surface preferably being positioned on the other side of the stop arm  12 . The LEDs  24  preferably are 1 watt to 3 watt, low heat, high intensity LEDs and are configured to accomplish the light output required to meet current photometric standards and specifications. 
         [0022]    Circuit components  30  are coupled to the PCB  22  and electrically couple the LEDs  24  to the contacts  33  and  34 . The circuit components  30  can be configured to regulate the voltage and current applied to the LEDs  24  and cause the flashing effect. One exemplary embodiment of the circuit components is shown in  FIG. 4  and includes a bridge circuit  32 , a voltage regulator  34 , and a flash controller  36 .  FIG. 5  illustrates an embodiment of a detailed component  30  layout for the PCB  22 . 
         [0023]    The bridge circuit  32  allows for greater freedom in mounting the lamp  10  to the socket  14 , as it can allow the base  20  to be connected to the socket  14  in a plurality of configurations. The socket  14  is connected to the supply of DC power. The existence of the bridge circuit  32  allows the lamp  10  to function regardless of whether the base  20  is inserted into the socket  14  either of, for example, two orientations. In either of the two orientations, the contacts  33  &amp;  34  (DC +/−) will align with power output/input on the socket  14  and provide DC power to the lamp  10 . When the lamp  10  is mounted into the socket  14 , the bridge circuit adjusts for the positive/negative points on the bottom of the lamp  10  and corrects the flow of DC current. According to one exemplary embodiment the bridge circuit  32  includes four diodes D 1 -D 4  (see  FIG. 5 , pt#IN 4004 ) that will adjust the input voltage from random direction to fixed direction. This allows the lamp  10  to function correctly regardless of the orientation of the lamp  10  relative into the socket  14 . 
         [0024]    The voltage regulator  34  provides a substantially constant voltage to the LEDs  24 . The voltage regulator  34 , labeled as component U 2  (pt#LM 317 ) in  FIG. 5 , is electrically connected to the bridge circuit  32 , then to the flash controller  36 , and to the LEDs  24  through a series of resistors R 1 -R 12  of differing values (see  FIG. 5  component list). The voltage regulator  34  (U 2 ) lowers the input voltage to from &gt;12VDC to 6.2-7VDC, thereby protecting the LEDs  24  and other components  30 . The resistors R 1 -R 12  are added to restrict the current and further protect the LEDs  24  and components  30 , and prevent the LED  24  brightness from being affected when input voltage changes (e.g., during voltage spikes). 
         [0025]    The flash controller  36  can cause the LEDs  24  to generate flashing light. The flash controller  36  ( FIG. 5 ; U 1  pt#NE 555 ) is electrically connected to the voltage regulator  34  ( FIG. 5 ; U 2 ) and the LEDs  24  through the resistors R 1 -R 12 , and causes and regulates the flashing effect to an output frequency of preferably 11.2 Hz/58.2% duty cycle. Thus the flash controller ( FIG. 5  U 1 ) causes the LEDs  24  to generate the rapid flash effect. 
         [0026]    The lamp  10 , according to a preferred embodiment of the invention, can be configured to fit and operate in an existing (incandescent) bulb socket on a school bus stop arm (e.g. SMC 1156DC). The LEDs  24  can be arranged on the PCB  22  in a manner so that they will fit on a conventional stop arm  12  within the existing space  32  between the lenses  31  (see  FIG. 7 ) designed for a conventional incandescent bulb on both the top and bottom half of the school bus stop arm  12 . Because the lamp  10  uses the existing incandescent bulb socket and in view of the relatively compact construction of the lamp  10 , only a minimal effort is needed to substitute the lamp  10  for an existing incandescent bulb. For example, the effort required could be no more than is needed to replace a conventional incandescent bulb. 
         [0027]    Additionally, the lamp  10  can be configured to emit light in a rapid flash pattern, without requiring modification of the existing school bus stop arm  12 . By emitting light in a rapid flash manner and meeting all pertaining federal specifications the stop arm will benefit with the gain of the strobe like effect of using rapid flash technology, grabbing added motorist attention. These benefits are the same as those employed through rapid flash light technology commonly found on many of today&#39;s emergency vehicles. 
         [0028]    The lamp can be configured to include all the benefits of LED technology including efficiency, lower power consumption, and product longevity, with rapid flash technology to attract more motorist attention. The lamp can be configured to use existing incandescent sockets to avoid the costly retrofitting that is needed with currently known products. The ease of a ‘plug and play’ product such as described in this disclosure will be made more cost effective through the combination low LED count/low cost solution with the decreased amount of time needed to convert the stop arm. The intent is that school bus safety is allowed to be enhanced through more widespread use of (advanced warning) lighting. 
         [0029]    Given the various embodiments disclosed above and shown in the figures, it is contemplated that various aspects of the different embodiments may be transferable to other embodiments; thus the features of each embodiment is transferable to other embodiments. 
         [0030]    With the above-disclosure, various embodiments of the LED stop arm lamp are disclosed. Given the disclosure of the present invention, one versed in the art would appreciate that there may be other embodiments and modifications within the scope and spirit of the invention. Accordingly, all modifications attainable by one versed in the art from the present disclosure within the scope and spirit of the present invention are to be included as further embodiments of the present invention. The scope of the present invention is to be defined as set forth in the following claims.