Abstract:
A railroad highway crossing signal electronic assembly for use on bi-directional tracks, where a control unit sends AC voltage to an approaching rail segment wherein a rectifier receives AV voltage and discharges DC voltage which is sent back to a relay which controls lights on a gate arm. There is also a separate high current DC output to tracks. When shorted, the high current DC output creates sparks to improve detection of a train.

Description:
CROSS REFERENCE 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method of improving shunt detection on railroad tracks and to a railroad highway crossing signal electronic assembly, and more particularly, but not by way of limitation, to a railroad highway crossing signal electronic assembly that improves train detection on rails with poor shunting conditions. 
     2. Description of the Related Art 
     Grade-crossing signals and gate arms can be actuated by a variety of track circuits. A traditional relay circuit has often been used for grade-crossing signals and gate arms. 
     When the circuit detects the presence of a train, it actuates circuits that cause grade-crossing signals to begin flashing and cause gates to be lowered if train exists in the crossing. 
     Grade crossing predictor circuits are able to determine a distance from the train to the crossing and can determine whether the train is approaching the crossing or moving away from the crossing. This ability allows a controller to activate a warning system with a warning time prior to the train reaching the crossing. 
     Some prior circuits employ tuned shunts at either end of an approach area to a crossing and work by transmitting a signal through the rails and shunts and sensing an inductance (or impedance) of the circuit formed by the track rails and shunts. 
     When a train approaches a crossing, the train&#39;s axles and wheels create a short circuit between the pair of rails, which towers the total apparent inductance. 
     By monitoring the inductance or impedance changes, the location of the train can be determined so that a warning system can be activated. 
     Unfortunately, grade crossing circuits do not work in all circumstances. For example, grade crossing circuits may not work, or may not work reliably, with poor shunting conditions. 
     Poor shunting conditions may be caused by low traffic on the rails, which may in turn cause rusts on the rails. 
     Poor shunting conditions may also be caused by light weight cars on the rails. 
     Poor shunting conditions may also be caused by vegetation, such as weeds, growing around the tracks, which prevents an electrical connection between the wheels and the tracks. 
     Based on the foregoing, it is desirable to provide a railroad highway crossing signal electronic assembly with high current sparks to jump gaps between the wheels and the track rails to overcome poor shunting conditions. 
     It is further desirable to provide an improved railroad highway crossing signal electronic assembly that can manage a C-style circuit. 
     It is further desirable to make a more cost effective railroad highway crossing signal electronic assembly that uses a single integrated unit to manage train detection and to activate warning lights and gates. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a method to improve shunt detection on railroad tracks. A high direct current driver provides sparks to a railroad track segment to improve shunting conditions. The invention also relates to an integrated railroad highway crossing signal electronic assembly which improves shunt detection and detects the presence of trains. The assembly includes a housing, a power inverter, a blackout detector, an isolated step down transformer, and a high current driver. 
     The power inverter may receive voltage from an external power supply, which makes the inverter oscillate to produce an output of power. The power inverter may be connected electronically to the blackout detector. The blackout detector may detect VAC presence and switch to DC power supply when the VAC is absent. The blackout detector may revert back to AC power when it is available. The blackout detector may be connected electronically to the power inverter. The blackout detector may also be connected electronically to the isolated step down transformer. 
     The isolated step down transformer may take VAC or the output of the power inverter and produce outputs of VAC with multiple ampere capacities each. The isolated step down transformer may be connected electronically to the blackout detector. The isolated step down transformer may be connected electronically to the high current driver. The isolated step down transformer may be connected electronically to AC outlets. 
     The high current driver may turn the AC output from the isolated step down transformer to a high current output capable of driving multiple amperes of DC current. The high current driver may be connected electronically to the isolated step down transformer. The high current driver may be connected electronically to a high DC current output. 
     Additionally, the railroad highway crossing signal electronic assembly may be used to manage a C-style circuit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic view of a crossing signal circuit with unoccupied train track segments as shown in the prior art; 
         FIG. 2  is a diagrammatic view of a crossing signal circuit with occupied train track segments as shown in the prior art; 
         FIG. 3  is a schematic block diagram of a railroad highway crossing signal electronic assembly in accordance with the present invention; 
         FIG. 4  is a schematic diagram of the railroad highway crossing signal electronic assembly shown in  FIG. 3  connected to a C-style circuit in accordance with the present invention; 
         FIG. 5  is an internal perspective view of the railroad highway crossing signal electronic assembly in accordance with the present invention; and 
         FIG. 6  is another perspective view of the railroad highway crossing signal electronic assembly in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The devices and methods discussed herein are merely illustrative of specific manners in which to make and use this invention and are not to be interpreted as limiting in scope. 
     While the devices and methods have been described with a certain degree of particularity, it is to be noted that many modifications may be made in the details of the construction and the arrangement of the devices and components without departing from the spirit and scope of this disclosure. It is understood that the devices and methods are not limited to the embodiments set forth herein for purposes of exemplification. 
     The present invention relates to a method of improving shunt detection on bi-directional railroad tracks, and to an integrated railroad highway crossing signal electronic assembly. More particularly, but not by way of limitation, the present invention provides a method of improving shunt detection using high current DC output to railroad track rails. 
       FIG. 1  depicts a prior art crossing signal circuit with unoccupied train track segments  10 . A battery or other power source  12  is electrically connected to a relay  14  through a pair of rails. The relay is, in turn, electrically connected to a gate arm mechanism  16 , which alerts drivers and/or pedestrians when a train is near once it is activated. 
       FIG. 2  depicts a prior art crossing signal circuit with an occupied train track segment  10 . A battery or other power source  12  generates a current to a segment of train tracks. When the current is shorted by train wheels and axles  18  breaking the connection, a signal relay  14  is de-energized. When the signal relay  14  is de-energized, a signal is sent to the gate arm mechanism  16  and warning lights which begins to alert drivers or pedestrians that the train is coming on the tracks. 
       FIG. 3  depicts a block diagram of an integrated railroad highway crossing signal electronic assembly  38  in accordance with the present invention. Under normal conditions, power is supplied by an alternating current (AC) power source  12 , such as a 110 VAC. A power inverter  22  is electronically connected and receives voltage from an external DC power supply  20  of between 12 VDC and 13.5 VDC. This power supply  20  makes the power inverter  22  oscillate to produce a peak output of 170 VAC. 
     A blackout detector  24  detects presence of the alternating current (VAC)  12  and switches to the DC power supply  20  when the VAC is absent. When the AC power  12  is available, the blackout detector will revert to using the AC power. The blackout detector  24  is connected electrically to both the power supply  12  and to the power inverter  22 . 
     An isolated step down transformer  26  receives 110 VAC or the output of the power inverter  22  and produces four separate outputs of 6.3 VAC nominal with 3 amperes of capacities each. The isolated step down transformer  26  sends an output to a first AC output  28 . The isolated step down transformer also sends an output to a second AC output  30 . Finally, the isolated step down transformer sends an output to a third AC output  32 . 
     A separate high current driver  34  turns the AC output from the isolated step down transformer  26  into a high current DC output  36  capable of driving up to 3 amperes of direct current (DC). 
       FIG. 4  depicts a simplified circuit diagram of the integrated railroad highway crossing signal electronic assembly  38  connected to a C-style circuit. Three isolated rail track segments  50 ,  52 , and  54  are provided, which are isolated from each other by a gap and insulating material. Three rectifiers  44 ,  46 , and  48 , respectively, are provided, each of which span the rails of the track segments  50 ,  52  and  54 , respectively. A relay  14 ,  40 , and  42  for each rail track segment  50 ,  52  and  54 , respectively. 
     A first AC output  28  is connected to the rails of the first rail track segment  50 . A second AC output  30  is connected to the rails of the second rail track segment  52 . A third AC output  32  is connected to the rails of the third rail track segment  54 . Alternating current is delivered to each track segment as shown by arrow  120 . High current DC output  36  is connected to the first track and third track segments. Diodes  56 ,  58 ,  60 , and  62  may be connected to high current output  34  to prevent high current DC output  34  shunted in one track to be shorted at the other track. 
     A C-style circuit may be utilized with the bi-directional railroad tracks  10  having the three isolated rail track segments  50 ,  52 , and  54 . Train wheels and axles  18  may shunt the current between one of the track segments. When this occurs, the correspondent rectifier  44 ,  46 , or  48  will be shorted, taking off the direct current in the corresponding segment  50 ,  52  or  54 , de-energizing the corresponding relay  14 ,  40  or  42 . When the direct current is sent to one of the relays, it de-energizes the relay. This de-energizing of the relay causes lights and/or a gate arm assembly  16  to function, which warns drivers or pedestrians that a train is on the tracks and is nearby. 
     Diodes  56 ,  58 ,  60 , and  62  prevent the high current DC output  36  from being short circuited. For example, AC output is being delivered to the rails, illustrated by arrows  120 , so rectifiers  44  and  48  receive AC voltage and deliver DC voltage, illustrated by arrows  122 . When the train wheels enter segment  50  and short out the diode  44 , the high current DC output  36  is also shorted out. DC voltage in that segment  50  disappears, dropping relay  14 , but keeping the high DC output in segment  54  which is not shorted out. 
     The separate high current DC output  36  is sent to the track segments  50  and  54  all the time when the AC output has been shunted by the train. This high current DC output provides high current sparks and helps eliminate rust and improves detection of the train. The high current DC output  36  may be attached to the first  50  and third segments  54 , but does not need to be attached to the island  52 , or the middle segment. 
       FIG. 5  depicts an internal view of the integrated railroad highway crossing signal electronic assembly  38 . The isolated step down transformer  26  is shown attached to a front panel  90 . The power inverter  22  is also attached to the front panel  90 . A printed control board  88 , used to mechanically support and electrically connect the electronic components of the claimed invention, is shown attached to the front panel  90 . A heatsink mounting plate  92  acts as a heatsink which cools down the power component. 
       FIG. 6  depicts another perspective view of the railroad highway crossing signal electronic assembly  38 . AC power inputs  94  and  96  are shown which will be connected to the AC power source  12 . These are internally connected to the blackout detector (not shown), DC terminal inputs  98  and  100  are shown which will be connected to an external DC power source to provide a DC power supply  20 . These are internally connected to the power inverter  22  (not shown). A capacitor  102 , which will smooth the power output, may be a 40000 uf/25V capacitor. The capacitor  102  may also be used to block alternate current, while allowing direct current. A relay  104  is shown to operate a mechanical switch device. A resistor  106 , to implement electrical resistance, may be an adjustable 1 ohm resistor. A bridge rectifier  108  may be used to perform a conversion of AC input to DC output. A choke  110  may be used to block higher-frequency alternating current in an electrical circuit, while allowing lower frequency or DC current to pass. A power indicator light  112  may be used to flash a light when the assembly is functioning. A mounting board  114  allows for mounting of different aspects of claimed invention. 
     The present invention provides an integrated railroad highway crossing signal electronic assembly which will improve shunt detection on railroad tracks while activating and controlling all warning lights and gate arm mechanisms. 
     Whereas, the present invention has been described in relation to the drawings attached hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention.