Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2001-01-09
2003-01-07
Lieu, Julie (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S907000, C340S931000, C315S130000
Reexamination Certificate
active
06504485
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a monitoring apparatus for advising if an illumination condition of traffic signal lights is normal or abnormal, and a control apparatus for controlling the signal lights based on an advisory signal from the monitoring apparatus.
BACKGROUND ART
With traffic signal units provided for example at a road intersection or the like, if an illumination condition of the signal lights is abnormal, then a traffic conflict can result. In particular, if the green lights (referred to hereunder as G lights) for permitting people and vehicles to proceed, are simultaneously illuminated for the respective directions of the intersecting roads, an extremely dangerous situation results. To avoid this situation, monitoring for simultaneous illumination of the G lights for the respective directions of the intersecting roads has heretofore mainly involved using a hard logic, for example to detect the terminal voltage of the signal lights via a voltage transformer or the like.
With conventional simultaneous G light illumination detection methods, voltage transformers are connected across the terminals of the G lights, so that a voltage is produced in the respective voltage transformers when the G lights illuminate, the arrangement being such that when a G light pair for the respective directions of the intersecting roads are illuminated simultaneously, G light simultaneous illumination (danger condition) is advised by the presence of a voltage (corresponding to a high energy condition). That is to say, the arrangement is such that a danger condition is advised by a high energy condition. In this case, if a fault occurs where the output to the monitoring circuit itself, which includes for example the voltage transformer, has a fault giving zero, then there is a problem in that if a simultaneous illumination of the G light pair for the respective intersecting roads occurs, this cannot be advised.
Moreover, in most cases it has not been possible to reach a stage where the illumination condition of a plurality of signal lights is monitored by only monitoring for simultaneous illumination of a G light pair for respective intersecting roads.
In view of the above situation, it is an object of the present invention to provide a monitoring apparatus for fail-safe monitoring for abnormal conditions such as, simultaneous illumination of traffic proceed permit signal lights, or signal light burn-out. Moreover, it is an object of the invention to provide a signal light control apparatus, which uses such a fail-safe monitoring apparatus.
DISCLOSURE OF THE INVENTION
Accordingly, the monitoring apparatus for traffic signal lights according to the present invention comprises: a sensor device for detecting an illumination condition of traffic signal lights; and a judgment device for generating an output of logic value 1 corresponding to a high energy condition indicating a normal condition of the signal lights when, based on an output from the sensor device, the number of illuminated or non illuminated signal lights is a predetermined number, and generating an output of logic value 0 corresponding to a low energy condition indicating an abnormal condition of the signal lights when not the predetermined number.
With this construction, since when the signal lights are normal and thus safe, this can be advised by a high energy condition (logic value 1) while when the signal lights are abnormal and thus dangerous, this can be advised by a low energy condition (logic value 0), then when a fault occurs where the sensor device or judgment device gives a zero output, this dangerous situation can be advised. Hence reliability of the signal light monitoring can be improved.
The construction may be such that the judgment device generates an output of logic value 1 when the number of illuminated signal lights is a predetermined number, and generates an output of logic value 0 indicating a signal light burn-out fault when not the predetermined number.
If in this way judgment of a signal light burn-out fault is carried out from the number of illuminated lights, with a logic value 1 for when the signal lights are illuminated, then the output level goes to the low side with both a signal light burn-out fault, and a zero output fault for example in the sensor. Therefore it is possible to warn off danger, even in the case where both faults coincide.
The construction may be such that the output from the judgment device is output via an on-delay circuit having a delay time which is longer than an illumination period of the signal lights, or via a self-hold circuit with the output from the judgment device as a reset input signal, and a signal light power source switch on signal as a trigger input signal, which self-holds the trigger input signal.
In this way, even in the case where burn-out fault information appears intermittently in the illumination period of the signal light, this information output can be continuously advised until conditions return to normal.
Moreover, the construction may be such that the judgment device generates an output of logic value 1 when the number of non illuminated signal lights is a predetermined number, and generates an output of logic value 0 indicating a signal light simultaneous illumination fault where simultaneous illumination is not permitted, when not the predetermined number.
If in this way judgment of a signal light simultaneous illumination fault is carried out from the number of non illuminated lights, with a logic value 1 for when the signal lights are not illuminated, then the output level goes to the low side with both a signal light simultaneous illumination fault, and a zero output fault for example in the sensor. Therefore it is possible to warn off danger, even in the case where both faults coincide.
The construction may be such that the output from the judgment device is output via an on-delay circuit having a delay time which is longer than an illumination period of the signal lights, or a self-hold circuit with the output from the judgment device as a reset input signal, and a signal light power source switch on signal as a trigger input signal, which self-holds the trigger input signal.
In this way, even in the case where simultaneous illumination fault information appears intermittently in the illumination period of the signal lights, this information output can be continuously advised until conditions return to normal.
The construction is such that an illumination condition of respective signal lights for respective road directions of a two way intersection where two roads intersect is detected using sensor devices which output a binary logic signal, generating an AC signal and outputting a logic value 1 when a signal light is illuminated, and not generating an AC signal and outputting a logic value 0 when the signal light is not illuminated, and there is provided a judgment device which, based on the output conditions from respective sensor devices for each of the respective signal lights, generates an output of logic value 1 corresponding to a high energy condition when the signal lights are normal, and generates an output of logic value 0 corresponding to a low energy condition at the time of a simultaneous illumination of the signal lights where simultaneous illumination is not permitted.
Basically, the construction may be such that the judgment device comprises; a first adding circuit for adding the logic signals of the respective sensor devices for detecting an illumination condition of respective green lights indicating permission to proceed in the respective road directions, and a first level detection circuit for level detecting the addition value from the first adding circuit, the construction being such that the first level detection circuit generates an output of logic value 1 when the addition value is 1, and generates an output of logic value 0 when the addition value is 2. Consequently it is possible to monitor for simultaneous illumination of the green lights.
Furthermore, the construction may be such that the judgmen
Asada Norihiro
Fujimoto Hidetoshi
Futsuhara Koichi
Jinno Yoshitaka
Mazawa Heisaku
Lieu Julie
McDermott & Will & Emery
The Nippon Signal Co. Ltd.
LandOfFree
Monitoring apparatus and control apparatus for traffic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Monitoring apparatus and control apparatus for traffic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Monitoring apparatus and control apparatus for traffic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3059078