Abstract:
Vehicle 4-way emergency flasher circuits are modified by circuit branches which enable flashing selected pairs of emergency lamps at a higher frequency or in other discernible different ways. These selected lamps become visible and recognizable as right or left turn signals while the 4-way flasher circuit is operating.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to vehicle signals which are generated to become visible and recognizable as turn signals while the vehicle&#39;s 4-way hazard warning lights are operating. 
         [0003]    2. Description of Prior Technology and Problem 
         [0004]    US passenger vehicles and light trucks are required by the Department of Transportation (DOT) and the National Highway Traffic Safety Administration (NHTSA) to have flashing 4-way emergency hazard lights to warn approaching vehicles of the presence of an existing or imminent road hazard caused by a slowly moving or stopped vehicle. This hazard signal alerts approaching drivers to slow down and proceed with caution to avoid rear end crashes or other unsafe consequences during emergency or hazardous conditions. 
         [0005]    Copending application Ser. No. 12/136,370, entitled CONTINUOUS ENHANCED VEHICLE HAZARD WARNING LIGHTS, filed by one of the present co-applicants, details the enormous losses in life, injuries, property damage and economic costs that are experienced every year in the USA from rear end crashes. That application is incorporated in its entirety by reference herein. Likewise, U.S. Pat. No. 7,352,278 issued Apr. 1, 2008 to assignee, Tritel, LLC, also cites the source of the accident statistics and is incorporated in its entirety by reference herein. 
         [0006]    Both the incorporated application and the patent describe enhancement of the hazard warning lights by generating flashing lights in a triangular configuration in the rear of a slowly moving or stopped vehicle. Such modifications are more attention getting and alerting than conventional rear hazard lighting. Therefore, those innovations are ways of reducing or avoiding rear end crashes and thus improve highway safety. 
         [0007]    Even with the advent of such improvements there is yet another difficulty with the conventional 4-way hazard lighting that is the focus of the present invention. In particular, when either the conventional or above cited improved hazard lights are operating, the vehicle no longer has the capability to give turn signals to approaching traffic. This is because usually the same flasher that activates the flashing 4-way hazard lights is also used to generate conventional left or right vehicle turn signal lights. Furthermore, the left and right vehicle turn signal lights typically are simultaneously flashed to generate the 4-way hazard lights. Therefore, when the emergency lamps are flashing, they mask attempts to display a turn signal. 
         [0008]    In many hazardous conditions, a line of slowly moving or stationary vehicles often develops due to obstruction of a road or highway by an accident or stalled vehicle or other extraordinary situation ahead. Vehicles also occasionally must travel at unusually slow speeds, for example, due to mechanical problems, weather conditions or because they are towing a heavy trailer. Drivers confronted with such situations often need to warn oncoming traffic of the hazardous conditions by using their 4-way flashers. If, however, such drivers simultaneously need to turn, they have no effective way of signaling their intent to undertake such maneuvers. Therefore, there is a need for achieving an added measure of safety by providing a signal that will inform others not only of a hazardous situation, but also that the vehicle with its hazard lights flashing is about to turn left or right. 
       SUMMARY OF INVENTION 
       [0009]    The present invention provides a simple, effective and inexpensive solution to the above discussed problem. In particular, the invention enables distinctively flashing the left or right turn signal lights at least in the rear, and preferably in the front of a vehicle as well, to simultaneously signal a turn is imminent or in progress while the 4-way flasher is operating. This is achieved by illuminating the left or right turn signal lights in a discernibly different manner than the other lights being activated by the 4-way flasher. In particular, the turn signal lights are flashed at a higher frequency or lower frequency than the remaining flashing 4-way emergency lamps, or with a different on/off duty cycle, or other techniques that would make the output of the turn signal lights noticeably different. These techniques include changing the illumination intensity of the turn signal lights. This provides drivers with the opportunity to indicate that a left or right turn is about to begin or has begun in the course of a hazardous road condition signified by the remaining flashing 4-way lamps. 
         [0010]    Further features and details of the invention will be understood by reference to the following drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  shows a sampling of pulses that can be used to simultaneously activate the hazard lights and the innovative turn signal lights 
           [0012]      FIG. 2  is a block circuit diagram for performing one embodiment of the invention. 
           [0013]      FIG. 3  is a block circuit diagram for performing another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    In  FIG. 1   a  the illumination of the 4-way hazard lights is represented by a series of on and off pulses flashing at a predetermined frequency. The 4-way hazard lights typically include two emergency lamps at the front of the vehicle and two in the rear. It is also true that in some vehicles, especially larger passenger cars and trucks, additional emergency flashing lights are used. For example, the 4-way hazard lighting system in some large vehicles incorporate emergency lamps built into the external left and right rear view mirrors or in other positions such as in the mid section of the vehicle. 
         [0015]    In  FIG. 1   b  the illumination of the turn signal lamps is represented by a series of pulses that are at twice the frequency of the rest of the hazard lights, but in phase and at the same illumination intensity. The simultaneous operation of the hazard lights according to  1   a  and the turn signals lights according to  1   b  will allow the turn signal to be communicated to approaching drivers during a hazardous situation. 
         [0016]    In  FIG. 1   c  the illumination of the turn signal lights is represented by a series of pulses where the 4-way flasher pulses are applied to the turn signal lights, but with an additional pulse between each of the hazard pulses. 
         [0017]    In  FIG. 1   d  the turn signal lights are operated at a higher illumination intensity. 
         [0018]    In the embodiment shown in  FIG. 2 , lead line  10  refers to the vehicle&#39;s electrical source. Lead line  12  refers to a switch which initiates operation of the vehicle&#39;s 4-way hazard lights, normally the four turn signal lamps, two in the front and two in the rear of the vehicle. 
         [0019]    Upon pressing switch  12 , the 4-way flasher circuit  14  begins emitting pulsed current into output lead  16 . Branch lead  18  normally closed relay  46 , and lead lines  19  and  26  transmit the pulses to the right front turn signal lamp  24  when a right turn is chosen by a driver. Similarly, branch lead  18 A, relay  46 A, and lead  19 A and  26 A transmit the pulses to the left front turn signal lamp  24 A when a left turn is chosen. 
         [0020]    Branch leads  28  and  32  transmit the pulses to the right rear turn signal lamp  30 . Similarly, branch lead  28 A and  32 A transmit the pulses to the left rear turn signal lamp  30 A. Parallel branched lead  48  and relay  37  transmit the pulses to the centrally located lamp  34 . 
         [0021]    Lamp  34  may be either the center high mounted stop lamp (“CHMSL”) mandated by NHTSA”), as described in U.S. Pat. No. 7,352,278, or an additional (fifth) lamp, as described in copending application Ser. No. 12/136,370. At this point, all four of the turn signal lamps  24 ,  24 A,  30 ,  30 A and fifth lamp  34  are simultaneously and synchronously flashing to function as the vehicle&#39;s hazard warning lights. Lamps  30 ,  30 A and  34  preferably form a flashing isosceles-shaped triangle in the rear of the vehicle, with lamp  34  at the apex and lamps  30  and  30 A at the base vertices. 
         [0022]    Switch  36  is a single pole, double throw switch that may be controlled by servo initiation in response to the driver&#39;s turn signal stalk, usually mounted on the vehicle&#39;s steering wheel post. Thus, if the driver desires to make a right turn, he or she shifts the stalk typically in the upward direction. A corresponding signal sent to switch  36  shifts its pivoting pole to the position indicated by the upper chain line within switch  36 . 
         [0023]    This connects lead  20 , Frequency Multiplier  47 , and lead  22  to lead  38 . The pulses from the 4-way flasher circuit, as modified by the Frequency Multiplier  47 , are shunted into lead  38  and ultimately to lamps  24  and  30 . Simultaneously relay  47  is activated to open and thereby interrupt the pulses from the 4-way flasher from reaching lamps  24  and  30  directly. 
         [0024]    Lamps  24  and  30  will therefore flash at a higher frequency than lamps  34 ,  24 A and  30 A. Thus, approaching drivers will see a composite signal with components of lower frequency pulses indicating a hazard situation and higher frequency pulses indicating a right turn. This condition will end when the turn signal stalk returns to its neutral position following completion of the right turn. At that time, another signal to switch  36  will shift it to its neutral position, thus disconnecting the Frequency Multiplier pulses from the lead  38  and terminating the action of the upper circuit branch. Relay  46  will also return to its normal closed position so that the pulses from the 4-way flasher can again reach lamps  24  and  30  to resume flashing of all five hazard lamps in the normal ongoing manner. 
         [0025]    The lower circuit branch comprises the same components identified by the same reference numerals (plus suffixes “A”) as in the upper circuit branch, and operates in the same way when a left turn is made while the 4-way flasher circuit is operating. 
         [0026]    The frequency of the 4-way pulses preferably is approximately 105 pulses per minute. A higher frequency of 1.75 to 2.0 times greater is preferred for making the turn signal lights distinguishable from and recognizable as turn signals in comparison to the lower frequency pulses that illuminate the remaining flashing emergency lamp 
         [0027]    Although the embodiment disclosed in  FIG. 2  uses a frequency multiplier, the invention can be achieved by illuminating the selected turn signal lights in other ways. For example signal lights can be illuminated by using different duty cycles, pulse addition, frequency reduction or altered light intensity for the turn signal lights. For example, the illumination of the turn signal lights may be increased by replacing frequency multiplier  47  with an amplifier circuit to boost the voltage of the pulse received by means of lead  16 . 
         [0028]    In the circuit diagram of  FIG. 3 , the pulses from the  4  way flasher are configured to reach the five emergency lamps  24 ,  30 ,  24 A,  30 A and  34  when the hazard warning lights are activated. However, when a turn signal is called for and switch  36  is activated, the resulting modified pulses are transmitted only to the chosen turn signal lamps by the blocking actions of silicon diodes  52 ,  56 ,  52 A and  56 A against reverse current flow into the remaining flashing emergency lamps. The pulse converter  59  modifies the pulses received from the 4-way flasher via lead  16  by, for example, amplifying the voltage to increase illumination as shown in  FIG. 1   d  or by inserting additional pulses as shown in  FIG. 1   c.    
         [0029]    The invention has been described in terms of its functional principles and illustrative embodiments. Many variations of such embodiments will be obvious to one skilled in the art. Therefore, it should be understood that the ensuing claims are intended to cover all changes and modifications of the illustrative embodiments which fall within the literal scope of the claims and all equivalents thereof.