PROXIMITY WARNING SYSTEM WITH SILENT ZONES

• US 20100271214A1
• Filed: 04/29/2010
• Published: 10/28/2010
• Est. Priority Date: 10/25/2007
• Status: Active Grant

• Current Assignee: Strata Safety Products LLC (Strata Worldwide Holdings, Inc.)
• Original Assignee: Strata Proximity Systems, LLC (Strata Worldwide Holdings, Inc.)
• Inventors: Frederick, Larry D.
• Granted Patent: US 8,446,277 B2
• Time in Patent Office: Days
• US Class Current: 340/600
• CPC Class Codes: F16P 3/145 using magnetic technology
• CPC Class Codes: F16P 3/147 using electro-magnetic technology, e.g. tags or radar
• CPC Class Codes: G08B 21/0213 System disabling if a separation threshold is exceeded disabling electrical appliances in case of unplugging G08B13/1409
• CPC Class Codes: G08B 21/182 Level alarms, e.g. alarms responsive to variables exceeding a threshold

Abstract

Various proximity detection zones for work sites that require personnel to be in close proximity to various hazardous elements, such as machines, mobile equipment, remotely controlled machines, and operated vehicles can be shaped to fit specific equipment or work area configurations and may include one or more silent zones within the proximity warning zone in which an alarm is not sounded. The zones are determined by overlapping magnetic fields that expand and collapse at a selected operating frequency. Devices sense and measure the strength of the magnetic fields in which they are located and use the information to determine if they are in a silent or warning zone. Thus, it is possible to produce silent zones having desired shapes.

Claims

1. A method for providing a proximity warning comprising:

generating a first magnetic field;

generating a second magnetic field that overlaps the first magnetic field;

determining a location of a detector device with respect to the first and second magnetic fields, wherein the location is determined by detecting at least one of the first or second magnetic fields using the detector device; and

issuing a warning based on the location of the detector device.

2. The method of claim 1, wherein the warning is issued if the detector device is located within both the first and second magnetic fields.

3. The method of claim 1, wherein no warning is issued if the detector device is located within both the first and second magnetic fields.

4. The method of claim 1, wherein the warning is issued if the detector device is located only within the first magnetic field.

5. The method of claim 1, wherein no warning is issued if the detector device is not located within the first or second magnetic fields.

6. The method of claim 1, wherein the second magnetic field is located completely within the first magnetic field.

7. The method of claim 1, further comprising generating a third magnetic field that overlaps the first magnetic field, wherein the location of the detector device is determined with respect to the first, second and third magnetic fields by detecting the first, second and third magnetic fields using the detector device.

8. The method of claim 1, wherein the warning is issued to a worker who is carrying the detector device.

9. The method of claim 1, wherein the warning is issued to a machine that houses a magnetic field generator for generating the first and/or second magnetic fields.

10. The method of claim 9, wherein the warning is issued to an operator of the machine.

11. The method of claim 9, wherein the machine automatically performs certain actions upon receiving the warning.

12. The method of claim 1, wherein the first and second magnetic fields are low frequency magnetic fields.

13. A proximity warning system, comprising:

a first generator that generates a first magnetic field;

a second generator that generates a second magnetic field that overlaps the first magnetic field;

a detector device that measures the strength of the first and second magnetic fields and determines its location with respect to the first and second magnetic fields; and

an alarm device that issues a warning based on the location of the detector device.

14. The system of claim 13, wherein the alarm device issues the warning if the detector device is located within both the first and second magnetic fields.

15. The system of claim 13, wherein the alarm device does not issue the warning if the detector device is located within both the first and second magnetic fields.

16. The system of claim 13, wherein the alarm device issues the warning if the detector device is located only within the first magnetic field.

17. The system of claim 13, wherein the alarm device does not issue the warning if the detector device is not located within the first or second magnetic fields.

18. The system of claim 13, wherein the second magnetic field is located completely within the first magnetic field.

19. The system of claim 13, further comprising a third generator that generates a third magnetic field that overlaps the first magnetic field.

20. The system of claim 19, wherein the detector device measures the strength of the first, second, and third magnetic fields and determines its location with respect to the first, second, and third fields.

21. The system of claim 13, wherein the detector device and the alarm device are both located in a single device.

22. The system of claim 13, wherein the warning is issued to a worker.

23. The system of claim 13, wherein the warning is issued to a machine that houses the first and second generators.

24. The system of claim 22, wherein the warning is issued to an operator of the machine.

25. The system of claim 22, wherein the machine automatically performs certain actions upon receiving the warning.

26. The system of claim 13, wherein the first and second magnetic fields are low frequency magnetic fields.