Non-directional magnet field based proximity receiver with multiple warning and machine shutdown capability

• US 6,810,353 B2
• Filed: 10/26/2001
• Issued: 10/26/2004
• Est. Priority Date: 10/26/2000
• Status: Expired due to Term

• Current Assignee: Strata Proximity Systems, LLC (Strata Worldwide Holdings, Inc.)
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Schiffbauer, William H.
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): LE, JOHN H
• Application Number:
  US10/045,741
• Publication Number:
  US 20020082803A1
• Time in Patent Office: 1,096 Days
• Field of Search: 702/158, 702/159, 342/118, 342/434, 342/427, 342/458, 340/539.11, 340/691.3, 340/573.1, 340/870.01, 340/941, 340/539
• US Class Current: 702/159
• CPC Class Codes: F16P 3/145 using magnetic technology
• CPC Class Codes: G08B 21/0213 System disabling if a separation threshold is exceeded disabling electrical appliances in case of unplugging G08B13/1409

Abstract

A hazardous area warning system with a non-directional magnetic field based proximity receiver for warning personnel of an attendant hazard. The receiver includes a x-axis receiver with an antenna directed in a x direction, a y-axis receiver with an antenna directed in a y direction and a z-axis receiver with an antenna directed in a z direction. The antennas may be a wire loop wrapped around a ferrite core. The output from each of the three receivers are combined in an adder. The combined result from the adder is representative of the distance between the receiver and a warning transmitter antenna. A comparator determines whether the received signal indicates an attendant hazard, i.e., the receiver is too close to the warning transmitter. The receiver wearer is warned of the attendant hazard, visually and/or tactilly, e.g., with warning lights and/or vibrations. An encoder encodes the signal indication and a transmitter transmits the encoded signal. A data link receiver (located, for example, at a potentially hazardous machine) receives the encoded signal from the proximity receiver. The data link receiver decodes the encoded signal and activates a safety indicator light in response to the decoded information, a green light indicating normal operation, a yellow light indicating a caution or potentially hazardous condition, and a red light indicating danger. The data link receiver may shutdown and/or disable the machinery in a caution or dangerous condition.

Claims

1. A hazardous area warning system for warning personnel of an attendant hazard when they may enter into hazardous areas, said system comprising:

a receiver for receiving a directional signal indicating proximity of a hazard, and including circuitry that indicates a level of the received directional signal in a plurality of different directions;

means for determining based on the indicated levels of the received directional signal in the plurality of different directions whether a received signal indicates proximity to an attendant hazard; and

means for transmitting in response to a determination that the received signal indicates proximity to an attendant hazard an indication signal indicating that a person wearing said receiver is in a hazardous area.

2. A system as in claim 1, wherein said receiver comprises:

x-axis receiving means directed along a x-axis and receiving a signal from a hazard zone transmitter;

y-axis receiving means directed along a y-axis and receiving a signal from said hazardous zone transmitter;

z-axis receiving means directed along a z-axis and receiving a signal from said hazardous zone transmitter, the x-, y-, and z-axes generally being mutually perpendicular to each other; and

means for combining received signals from said x-axis receiving means, said y-axis receiving means and z-axis receiving means.

3. A system as in claim 2, wherein each of said x-axis receiving means, said y-axis receiving means, and said z-axis receiving means comprises:

an antenna directed along a respective axis;

an amplifier receiving signal from said antenna;

a filter filtering an output from said amplifier; and

a detector detecting the output of said filter to determine whether a signal is present in said output.

4. A system as in claim 3, wherein said antenna is a ferrite rod wrapped in wire.

5. A system as in claim 3, wherein said determining means comprises a comparator, said comparator determining whether an output of said combining means indicates that said directional receiving means is closer than a first distance to said transmitter.

6. A system as in claim 5, wherein said comparator further determines whether said receiver is closer than a second distance to said transmitter.

7. A system as in claim 6, wherein said determining means further includes a caution output linked to a first output of a decoder, a danger output connected to a second output of said decoder and an encoder connected to said first output and said second output.

8. A system as in claim 7, wherein when said comparator determines said receiver is within said first distance, said comparator places an output signal on said caution output;

and when said comparator determines said receiver is within said second distance, said comparator places an output signal on said danger output.

9. A system as in claim 8, wherein said encoder encodes any outputs placed on said caution output and said danger output.

10. A system as in claim 7, wherein said danger output comprises vibrating means for providing personnel with a tactile indication of danger.

11. A system as in claim 1, further comprising a data link receiver, said data link receiver comprising data receiver means receiving a signal from said transmitting means;

decoder means decoding said received signal;

driver means driving a plurality of outputs responsive to said decoder means; and

indicator means indicating a safety state responsive to said driver means.

12. A system as in claim 11, wherein said indicator means includes a yellow light, a red light and a green light.

13. A system as in claim 12, wherein said yellow light, red light and green light are LEDs and, said indicator means further includes a green status link LED.

14. A system as in claim 13, further comprising means for disabling a system being monitored.

15. A system as in claim 13, further comprising a first data logger logging danger situation occurrences;

and a second data logger logging caution condition occurrences.

16. A system as in claim 1, further comprising a warning transmitter, said warning transmitter including an antenna, said antenna being a ferrite rod wrapped in a loop of wire.

17. A system as in claim 16, wherein said warning transmitter further comprises an oscillator driving a resonant frequency;

a buffer amplifier buffering said resonant frequency from said oscillator; and

an antenna driver driving said resonant frequency onto said antenna.

18. A system as in claim 1 further comprising a data link receiver receiving the indication of whether a person wearing said directional receiving means is in a hazardous area as an encoded signal indicating a safety condition;

a decoder decoding said received encoded signal; and

a plurality of indicators indicating said safety condition.

19. A data link receiver as in claim 18, wherein said plurality of indicators include a danger zone indicator, a caution indicator and a normal indicator.

20. A data link receiver as in claim 19, wherein said plurality of indicators are a red light, yellow light and green light.

21. A data link receiver as in claim 20, wherein said red light, green light and yellow light are LEDs.

22. A non-directional proximity receiver comprising:

a x-axis receiver having an antenna directed in a first direction;

a y-axis receiver having an antenna directed in a second direction, said second direction being perpendicular to said first direction;

a z-axis receiver having an antenna directed in a third direction, said third direction being perpendicular to the plane of said first direction and said second direction;

an adder combining signals from said x-axis receiver, said y-axis receiver and said z-axis receiver;

a comparator determining whether a received signal indicates an attendant hazard;

an encoder encoding said indication of an attendant hazard in response to a determination that the received signal indicates an attendant hazard; and

a transmitter transmitting said encoded indication.

23. A proximity receiver as in claim 22, wherein each of said x-axis receiver, said y-axis receiver and said z-axis receiver further comprises an amplifier receiving a signal from said antenna;

a filter filtering output from said amplifier; and

a detector detecting a signal in said filtered output, an output of said detector being an input to said adder.

24. A proximity receiver as in claim 23, wherein each of said x-axis antenna, said y-axis antenna and said z-axis antenna is a wire wrapped around a ferrite rod.

25. A proximity receiver as in claim 24, further comprising a caution indicator connected to a first output of said comparator;

and a danger indicator connected to a second output of said comparator.

26. A proximity receiver as in claim 25, wherein said danger indicator is a motor, vibrations from said motor providing an indication of danger.