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1. US20020096604 - Contactless point detection system for railroad switch

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Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

What is claimed is:

1. A contactless detection system adapted for detection the movement of the switch points of a railroad switch comprising:
a transformer for detecting or sensing the position of the switch points, the transformer having a core adapted to link with the switch points, and further having a primary coil means and a secondary coil means wound around the core; and
an electronic interface means for receiving signals from the secondary coil means responsive to, and corresponding with, the positioning of the switch points;
wherein the secondary coil means has two secondary coils wound in opposite directions.
 
2. A contactless detection system as defined in claim 1, further comprising a source for providing a signal to the primary coil means.
 
3. A contactless detection system as defined in claim 2, further including a switch machine operative for moving the switch points.
 
4. A contactless detection system as defined in claim 3, further comprising a control device connected to the interface means.
 
5. A contactless detection system as defined in claim 1, in which there is a 180° phase shift between the output voltages of the two secondary coils such that as the core moves, the voltage amplitude of one secondary coil increases while the voltage amplitude of the other secondary coil decreases, wherein if the core is in the center of the transformer means, the voltage amplitudes of the two secondary coils will be equal.
 
6. A contactless detection system as defined in claim 5, wherein the absolute value of one secondary coil voltage plus the absolute value of the other secondary coil voltage is a constant whereby this constant value is a vital check signal, and means for sensing that the vital check signal is constant.
 
7. A contactless detection system as defined in claim 1, further including means for providing fail-safe operation of the system, said means including means for comparing a current voltage value with a previous voltage value from the output of the transformer, wherein the current voltage value must be within allowable limits, otherwise, the system is shut down.
 
8. A contactless detection system as defined in claim 1, comprising means for providing fail-safe operation of the system, said means including means for modulating an input signal to the primary coil means of the transformer at a specific frequency, and means for recognizing the absence of the frequency as the presence of a failure, and in response thereto, for shutting down the system.
 
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