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US 3,963,202 AGranted
Grade-crossing motorist warning system
AssigneeThe United States of America as represented by the Secretary of the Department of Transportation
InventorJohn B. Hopkins
Life of this patent
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Abstract
A railroad-highway grade-crossing warning system is accomplished by control circuitry for synchronizing the flash rates of incandescent and xenon lamps so as to produce a continuously uniform signal pattern which can be rapidly identified and understood by a motorist.
Claims5
A railroad-highway crossing warning system comprising:
- support means for location near a crossing;
- a primary warning system mounted on said support means and comprising a pair of incandescent lamp means oriented so as to be visible to a vehicle operator approaching the crossing;
- incandescent lamp control means for periodically energizing each of said incandescent lamp means at a given rate;
- an auxiliary warning system mounted on said support means and comprising a pair of xenon lamp means oriented so as to be simultaneously visible with said incandescent lamps to the same operator;
- xenon control means for periodically energizing each of said xenon lamp means at a predetermined rate;
- synchronization means for synchronizing said given and predetermined rates;
- and
- train detector means for producing a train-presence signal to activate said incandescent lamp control means and said xenon control means in response to approach of a train to the crossing.
5 more elements
Dependencies are inferred from the claim text.