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Floor distance sensor for an elevator car

  • US 4,245,721 A
  • Filed: 12/18/1978
  • Issued: 01/20/1981
  • Est. Priority Date: 12/18/1978
  • Status: Expired due to Term
First Claim
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1. A floor level distance sensing apparatus for an elevator car suspended in a shaft, comprising:

  • at least five paired energy radiating transmitters and receivers, said pairs being at predetermined distances from each other in the direction of car movement in the shaft and the energy from each transmitter activating its corresponding receiver,means for deactivating the receivers as the car reaches predetermined distances from the floor by blocking the energy transmission path between each said transmitter and its paired receiver and deactivating an increasing number of said receivers as the car approaches the floor level, the number and sequence of activated and deactivated receivers representing a maximum distance from the car to floorone of said receivers being located with respect to the others and with respect to the floor so that it can be activated and deactivated, when the car is within a preset level zone at the floor, for identifying car movement within that zone regardless of said number and sequence, andtwo of said receivers being in an opposite state from the remaining two when the car is within said level zone.

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