SELECTIVE INTRUSION ALARM SYSTEM

• US 3,732,555 A
• Filed: 03/13/1972
• Issued: 05/08/1973
• Est. Priority Date: 03/13/1972
• Status: Expired due to Term

• Current Assignee: SP-Microwave, Inc.
• Original Assignee: Harry F. Strenglein
• Inventors: Strenglein, Harry F.
• Primary Examiner(s): Trafton, David L.
• Application Number:
  US05/234,172
• Time in Patent Office: 421 Days
• Field of Search: 340/258R,258A,258B,258C,31,32,33,70,63 343/225,228
• US Class Current: 340/426.17
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: G08B 13/181 using active radiation detection systems
• CPC Class Codes: G08B 13/24 by interference with electromagnetic field distribution
• CPC Class Codes: Y10S 367/909 Collision avoidance

Abstract

A radio object detection, communication, and alarm system for aiding in maneuvering a truck for the delivery of goods at an unloading platform and for protecting the open truck from unauthorized entry during unloading includes portable radio communication means for inhibiting alarm operation when authorized personnel are present in a protected zone.

Claims

1. A selective intrusion alarm system comprising:

radiation receiver means for detecting signals reflected by intruding objects, first alarm means, receiver gating means for passing said detected signals to operate said first alarm means only for signals from objects within a selectable zone proximate said receiver means, and radiation transmitter means for inhibiting operation of said first alarm means, said radiation transmitter means being transportable by authorized personnel for permitting said personnel to enter said selectable zone without operating said first alarm means.

2. Apparatus as described in claim 1 additionally comprising second alarm means always responsive to said detected signals passed by said receiver gating means.

3. Apparatus as described in claim 1 wherein said receiver gating means comprises means for selectively passing said detected signals from at least a first or a second of said selectable zones.

4. Apparatus as described in claim 1 wherein said intrusion alarm system additionally comprises:

pulse synchronizer means, and base-band pulse transmitter means responsive to said synchronizer means, said receiver gating means being responsive to said synchronizer means for gating the output of said radiation receiver.

5. Apparatus as described in claim 4 comprising in series connection:

alarm driver circuit means responsive to said radiation receiver, inhibit circuit means, and said first alarm means.

6. Apparatus as described in claim 5 wherein:

said inhibit circuit means is responsive to low frequency receiver means, and said low frequency receiver means is responsive to said radiation transmitter means for inhibiting said first alarm means.

7. Apparatus as described in claim 6 wherein said radiation transmitter means comprises low frequency transmitter means cooperative with said low frequency receiver means.

8. Apparatus as described in claim 3 wherein:

said radiation receiver means is mounted at one end of a vehicle, said intrusion alarm system for a first setting of said receiver gating means is adapted to detect signals from objects toward which said end of said vehicle may be moved in a first zone, and said intrusion alarm system for a second setting of said receiver gating means is adapted to detect only objects in a second zone closer to said end of said vehicle than said first objects.