Interactive magnetic marker field for safety systems and complex proximity warning system

• US 20090109049A1
• Filed: 11/21/2007
• Published: 04/30/2009
• 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: Hammond, Paul L., Frederick, Larry D.
• Granted Patent: US 8,232,888 B2
• Time in Patent Office: Days
• US Class Current: 340/686.600
• CPC Class Codes: B60Q 9/008 for anti-collision purposes
• CPC Class Codes: F16P 3/14 the means being photocells or other devices sensitive without mechanical contact
• 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 21/0275 Electronic Article Surveillance [EAS] tag technology used for parent or child unit, e.g. same transmission technology, magnetic tag, RF tag, RFID
• CPC Class Codes: G08B 3/10 using electric transmission; using electromagnetic transmission
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

The invention relates to a complex proximity safety and warning system. The invention provides a safety system comprising a generator that generates a magnetic field that establishes a boundary, where the generator is capable of receiving radio frequency signals. Also provided is a radio frequency device that sends radio frequency signals, the radio frequency device being capable of sensing the magnetic field and generating a radio frequency response. In the safety system, the generator generates the magnetic field for a first predefined time period, and thereafter senses for a radio frequency response signal from the radio frequency device within a second predefined time period. The invention also provides for shaping safety zones by overlaying magnetic field boundaries to produce a different boundary. The invention also provides for varying the strength of magnetic fields by adjusting a width of a timed pulse.

Claims

1. A safety system, comprising:

a generator that generates a magnetic field that establishes a boundary, said generator being capable of receiving radio frequency signals; and

a radio frequency device that sends radio frequency signals, the radio frequency device being capable of sensing said magnetic field and generating a radio frequency response;

wherein said generator generates said magnetic field for a first predefined time period, and thereafter senses for a radio frequency response signal from said radio frequency device within a second predefined time period.

2. The safety system of claim 1, wherein said generator senses for a radio frequency response signal from said radio frequency device after a predetermined time delay.

3. The safety system of claim 1, wherein said generator is turned on and off to generate pulses of said magnetic field.

4. The safety system of claim 1, wherein said magnetic field operates at a low frequency of approximately 73 kHz.

5. The safety system of claim 1, wherein said radio frequency device generating a radio frequency response for a predetermined period of time.

6. The safety system of claim 1, further comprising multiple generators that generate oscillating magnetic fields in a random manner within selected periods of time.

7. The safety system of claim 1, wherein said radio frequency device is adapted to measure a strength of said magnetic field, and if the field strength exceeds a predetermined value, generated an alarm.

8. The safety system of claim 6, wherein said radio frequency device senses strengths of magnetic fields from said multiple generators and differentiates between said strengths to determine whether values have been exceeded and to produce an alarm that gives priority to the higher levels of said sensed strengths.

9. The safety system of claim 1, wherein said radio frequency device is adapted to vary duration of said generated radio frequency response.

10. The safety system of claim 3, wherein said generator is turned on and off to vary width of pulses thereby changing a strength of said magnetic field.

11. The safety system of claim 3, wherein said multiple generators generate oscillating magnetic fields sequentially and not at the same time.

12. The safety system of claim 1, wherein a size of the magnetic field is modified by changing a width of a waveform input to a tuned circuit of the generator.

13. A safety system for generating a shaped safety boundary, comprising:

a first generator that generates a first magnetic field having a first boundary; and

a second generator that generates a second magnetic field having a second boundary, wherein overlaying said first and second boundaries produces a different boundary;

wherein said first and second magnetic fields are generated in sequence.

14. The safety system of claim 13, wherein said first and second magnetic fields are low frequency magnetic fields.

15. The safety system of claim 13, further comprising a third generator that generates third magnetic field that is a safe zone within the safety system.

16. The safety system of claim 15, wherein said first, second and third generators generate pulsed magnetic fields having predefined time durations.

17. The safety system of claim 16, wherein said generators are turned on and off to vary width of pulses thereby changing strength of their respective said magnetic fields.

18. The safety system of claim 13, further comprising a radio frequency device that sends radio frequency signals, the radio frequency device being capable of sensing said magnetic fields and generating a radio frequency response.

19. The safety system of claim 13, wherein said different boundary has a shape of desired safety zone for a particular environment.

20. A magnetic field generator for a safety system, comprising:

a magnetic field generator controller for producing a timed pulse of oscillations;

an amplifier for amplifying said timed pulse of oscillations; and

a winding and a ferrite, wherein said timed pulse of amplified oscillations produces a current through said winding and ferrite, thereby creating a magnetic field having a strength;

wherein said strength of said magnetic field is variable by adjusting the width of the timed pulse.