Railway switches and signals – Electric automatic highway signals – mine doors – and gates – Car-actuated controller
Patent
1997-09-29
1999-07-20
Le, Mark T.
Railway switches and signals
Electric automatic highway signals, mine doors, and gates
Car-actuated controller
246 34R, 246126, 246127, 246128, 246255, 246246, 246249, B61L 100
Patent
active
059246529
ABSTRACT:
A reliable and consistent electrical contact path between the rails of a section of railroad track established by the shunting effect of the wheels and axles of a train is ensured by applying time-spaced, short duration electrical pulses to the rails at a voltage level sufficient to overcome poor wheel/rail contact. Each of the pulses is produced by a generator that discharges a capacitor across the rails. The narrow pulse width inductively isolates the pulse generator and associated track section from adjacent stretches of track, and the spacing between pulses further avoids interference with other types of electrical track equipment. A detector responsive to the voltage on the rails disables the pulse generator when the received voltage exceeds a threshold and thus indicates that no train wheels are present in the track section. In a grade crossing warning system, once activated the pulse generator and detector assume the role of the island detection circuit and maintain the crossing warning.
REFERENCES:
patent: 3622110 (1971-11-01), Campbell
patent: 3706098 (1972-12-01), Geiger
patent: 3777139 (1973-12-01), Peel
patent: 3781542 (1973-12-01), Brockman
patent: 3944173 (1976-03-01), Moe et al.
patent: 3977634 (1976-08-01), Smith
patent: 4062294 (1977-12-01), Cohen
patent: 4307860 (1981-12-01), Kuhn
patent: 4365777 (1982-12-01), Geiger
patent: 4581700 (1986-04-01), Farnham et al.
patent: 4619425 (1986-10-01), Nagel
patent: 4868538 (1989-09-01), Ballinger et al.
patent: 5170970 (1992-12-01), Ballinger
patent: 5417388 (1995-05-01), Stillwell
Harmon Industries, Inc.
Le Mark T.
LandOfFree
Island presence detected does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Island presence detected, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Island presence detected will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1315271