×

Multiple zone object detection system

  • US 4,459,689 A
  • Filed: 12/28/1981
  • Issued: 07/10/1984
  • Est. Priority Date: 12/28/1981
  • Status: Expired due to Fees
First Claim
Patent Images

1. Intrusion monitoring apparatus comprising:

  • a fixedly positioned source for transmitting a burst of energy in the direction to be monitored;

    means for indicating detection of reflection of said energy from objects located within given minimum and maximum distances along said direction;

    anmeans for precluding operation of said detection indicating means for reflections from objects located within one or more selected zones between said minimum and maximum distances so as to provide at least two object detection zones of fixed distance from said source with an interposed selected zone thereby permitting intrusion into or passage of objects through each of said selected zones without indication of detection while providing an indication of intrusion of objects into the remaining object detection zones.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×