PROXIMITY DETECTION SYSTEM

• US 20120268261A1
• Filed: 06/29/2012
• Published: 10/25/2012
• Est. Priority Date: 10/25/2007
• Status: Active Grant

• Current Assignee: Strata Safety Products LLC (Strata Worldwide Holdings, Inc.)
• Original Assignee: Strata Safety Products LLC (Strata Worldwide Holdings, Inc.)
• Inventors: Frederick, Larry D., Hammond, Paul L.
• Granted Patent: US 8,847,780 B2
• Time in Patent Office: Days
• US Class Current: 340/435
• 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 proximity detection system. The invention provides a proximity detection 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 proximity detection 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 proximity detection 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

1-20. -20. (canceled)

21. A collision avoidance system, comprising:

a vehicle;

a generator that generates a magnetic field, the generator being capable of receiving response signals; and

an alarm device that sends response signals, the alarm device being capable of sensing the magnetic field and generating a response signal;

wherein the generator generates said magnetic field for a first predefined time period, and senses for a response signal from the alarm device within a second predefined time period;

wherein the alarm device generates a response signal of a first length of time when the alarm device detects the magnetic field at a first strength,

wherein the alarm device generates a response signal of a second length of time when the alarm device detects the magnetic field at a second strength, and

wherein the first strength is different from the second strength and the first length of time is different from the second length of time.

22. The collision avoidance system of claim 21, wherein the generator is positioned at the vehicle.

23. The collision avoidance system of claim 22, wherein the alarm device is positioned at a dump point.

24. The collision avoidance system of claim 22, wherein the alarm device is positioned at a loading dock.

25. The collision avoidance system of claim 22, wherein the vehicle is a first vehicle, and further comprising a second vehicle, the alarm device being positioned at the second vehicle.

26. The collision avoidance system of claim 25, wherein the generator is a first generator and the alarm device is a first alarm device, and further comprising:

a second generator similar to the first generator, and a second alarm device similar to the first alarm device;

the second generator being positioned at the second vehicle, and the second alarm device being positioned at the first vehicle.

27. The collision avoidance system of claim 26, further comprising:

a first circuit connecting the first generator and the second alarm device, wherein the circuit disables the second alarm device during the time the first generator generates the magnetic field.

28. The collision avoidance system of claim 26, wherein the second alarm device generates an alarm when it senses the magnetic field of the second generator.

29. The collision avoidance system of claim 21, further comprising:

a plurality of vehicles;

a plurality of generators, each similar to the generator;

a plurality of alarm devices, each similar to the alarm device;

each of said vehicles having a corresponding one of the generators and alarm devices.

30. The collision avoidance system of claim 21, wherein said generator senses for a response signal from said alarm device after a predetermined time delay.

31. The collision avoidances system of claim 21, wherein said generator is turned on and off to generate pulses of said magnetic field.

32. The collision avoidance system of claim 21, wherein said magnetic field operates at a low frequency of approximately 73 kHz.

33. The collision avoidance system of claim 21, further comprising multiple generators that generate oscillating magnetic fields in a random manner within selected periods of time.

34. The collision avoidance system of claim 21, wherein said alarm device is adapted to measure a strength of said magnetic field, and if the field strength exceeds a predetermined value, generates an alarm.

35. The collision avoidance system of claim 33, wherein said alarm 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.

36. The collision avoidance system of claim 31, wherein said multiple generators generate oscillating magnetic fields sequentially and not at the same time.

37. The collision avoidance system of claim 21, wherein a size of the magnetic field is modified by changing a width of a waveform input to a tuned circuit of the generator.

38. A method for avoiding collision, comprising the steps of:

generating a magnetic field for a first predefined time period;

sensing the magnetic field and generating a response signal, the response signal being a first length of time when the alarm device detects the magnetic field at a first strength, and the response signal being a second length of time when the alarm device detects the magnetic field at a second strength; and

sensing for the response signal within a second predefined time period;

wherein the first strength is different from the second strength and the first length of time is different from the second length of time.

39. The method of claim 38, further comprising the steps of:

providing a plurality of vehicles;

providing a plurality of generators, each located at a corresponding vehicle and each for generating a corresponding magnetic field;

providing a plurality of alarm devices, each located at a corresponding vehicle and each for sensing a magnetic field and generating a response.

40. The method of claim 39, further comprising the step of disabling the alarm device during the time the generator generates the magnetic field for a corresponding vehicle.

41. A proximity detection system for complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site, the proximity detection system comprising:

a plurality of vehicles;

each of the vehicles having a plurality of magnetic field generators;

each of the plurality of magnetic field generators adapted to generate ping pulses of a magnetic field;

a plurality of alarm devices located on the persons of a plurality of workers and/or operators, each device being adapted to sense the ping pulse magnetic field in which the device is located and generate an echo response signal after a predetermined echo time delay;

the plurality of magnetic field generators being adapted to receive the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, to generate a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at semi-random time intervals;

the plurality of magnetic field generators being adapted to, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identify that the device is located in a particular magnetic field generated by one of the plurality of magnetic field generators.

42. A method for detecting proximity for complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site having a plurality of vehicles, comprising the steps of:

providing each of the vehicles with a plurality of magnetic field generators each of the plurality of magnetic field generators adapted to generate ping pulses of a magnetic field;

generating with a magnetic field generator ping pulses of a magnetic field;

providing a plurality of alarm devices located on the persons of a plurality of workers and/or operators, each device being sensing the ping pulse magnetic field in which the device is located and generate an echo response signal after a predetermined echo time delay;

the plurality of magnetic field generators receiving the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, generating a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at semi-random time intervals;

the plurality of magnetic field generators, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identifying that the device is located in a particular magnetic field generated by one of the plurality of magnetic field generators.

43. A proximity detection system for complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site, the proximity detection system comprising:

at least a first, second, and third magnetic field generator;

each of the first, second, and third magnetic field generators adapted to generate ping pulses of a first, second, and third magnetic field, respectively, the first, second, and third magnetic fields having an overlapping area and oscillating at low frequency during each ping pulse, the ping pulses having predetermined pulse durations and being generated at first semi-random time intervals;

a plurality of alarm devices, each device being adapted to sense the strength of the ping pulse magnetic field in which the device is located and to generate an echo response signal after a predetermined echo time delay, wherein the length of the predetermined echo time delay or the length of the echo response signal is based on the sensed strength of the ping pulse magnetic field;

the first, second, and third magnetic field generators being adapted to receive the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, to generate a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at second semi-random time intervals, the second semi-random time intervals being shorter than the first semi-random time intervals;

the first, second, and third magnetic field generators being adapted to, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identify that the device is located in the first, second, and/or third magnetic field, and to, based on the length of the predetermined echo time delay or the length of the echo response signal, identify that the device is located in a particular one of a plurality of zones of the first, second, and/or third magnetic field, each zone being smaller than the magnetic field;

wherein each of said plurality of alarm devices issues a first type of alarm when it senses a first zone of the first or second magnetic field and wherein each of said plurality of alarm devices issues a second type of alarm when it senses the first zone of both the first and second magnetic fields; and

wherein each of said plurality of alai in devices issues an alarm when it senses at least one of the first and second magnetic fields and not the third magnetic field, and wherein each of said plurality of alarm devices does not issue an alarm when it senses the third magnetic field only or in addition to the at least one of the first and second magnetic fields.

44. A method for complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site, comprising the steps of:

each of the first, second, and third magnetic field generators generating ping pulses of a first, second, and third magnetic field, respectively, the first, second, and third magnetic fields having an overlapping area and oscillating at low frequency during each ping pulse, the ping pulses having predetermined pulse durations and being generated at first semi-random time intervals;

a plurality of alarm devices, each sensing the strength of the ping pulse magnetic field in which the device is located and generating an echo response signal after a predetermined echo time delay, wherein the length of the predetermined echo time delay or the length of the echo response signal is based on the sensed strength of the ping pulse magnetic field;

the first, second, and third magnetic field generators receiving the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, generating a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at second semi-random time intervals, the second semi-random time intervals being shorter than the first semi-random time intervals;

the first, second, and third magnetic field generators, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identifying that the device is located in the first, second, and/or third magnetic field, and to, based on the length of the predetermined echo time delay or the length of the echo response signal, identifying that the device is located in a particular one of a plurality of zones of the first, second, and/or third magnetic field, each zone being smaller than the magnetic field;

each of said plurality of alarm devices issuing a first type of alai when it senses a first zone of the first or second magnetic field and each of said plurality of alarm devices issuing a second type of alarm when it senses the first zone of both the first and second magnetic fields; and

wherein each of said plurality of alarm devices issuing an alarm when it senses at least one of the first and second magnetic fields and not the third magnetic field, and each of said plurality of alarm devices not issuing an alarm when it senses the third magnetic field only or in addition to the at least one of the first and second magnetic fields.

45. A proximity detection system for reducing false alarms in complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site, the proximity detection system comprising:

a plurality of vehicles;

each of the vehicles having a plurality of magnetic field generators;

each of the plurality of magnetic field generators adapted to generate ping pulses of a magnetic field, the magnetic field oscillating at low frequency during each ping pulse, the ping pulses having predetermined pulse durations and being generated at first semi-random time intervals;

a plurality of alarm devices located on the persons of a plurality of workers and/or operators, each device being adapted to sense the ping pulse magnetic field in which the device is located and generate an echo response signal after a predetermined echo time delay;

the plurality of magnetic field generators being adapted to receive the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, to generate a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at second semi-random time intervals, the second semi-random time intervals being shorter than the first semi-random time intervals;

the plurality of magnetic field generators being adapted to, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identify that the device is located in a particular magnetic field generated by one of the plurality of magnetic field generators and send alarm signals only to the device and the corresponding vehicle.

46. A method for reducing false alarms in a proximity detection system for complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site having a plurality of vehicles, comprising the steps of:

providing each of the vehicles with a plurality of magnetic field generators;

each of the plurality of magnetic field generators generating ping pulses of a magnetic field, the magnetic field oscillating at low frequency during each ping pulse, the ping pulses having predetermined pulse durations and being generated at first semi-random time intervals;

a plurality of alarm devices located on the persons of a plurality of workers and/or operators, each device sensing the ping pulse magnetic field in which the device is located and generating an echo response signal after a predetermined echo time delay;

the plurality of magnetic field generators receiving the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, generating a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at second semi-random time intervals, the second semi-random time intervals being shorter than the first semi-random time intervals;

the plurality of magnetic field generators, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identifying that the device is located in a particular magnetic field generated by one of the plurality of magnetic field generators and sending alarm signals only to the device and the corresponding vehicle.

47. A proximity detection system for controlling a vehicle, comprising:

a vehicle;

a generator that generates a magnetic field, the generator being capable of receiving response signals; and

an alarm device that sends response signals, the alarm device being capable of sensing the magnetic field and generating a response signal;

wherein the generator generates said magnetic field for a first predefined time period, and senses for a response signal from the alarm device within a second predefined time period;

wherein the alarm device generates a response signal of a first length of time when the alarm device detects the magnetic field at a first strength,

wherein the alarm device generates a response signal of a second length of time when the alarm device detects the magnetic field at a second strength,

wherein the first strength is different from the second strength and the first length of time is different from the second length of time; and

the generator being capable of generating an alarm signal to the operator of the vehicle and of sending a signal to shut down the vehicle, upon sensing a response signal of a predetermined strength.

48. A method of controlling a vehicle in a proximity detection system, comprising the steps of:

a generator generating a magnetic field, the generator receiving response signals; and

an alarm device alarm device sensing the magnetic field and generating a response signal;

wherein the generator generates said magnetic field for a first predefined time period, and senses for a response signal from the alarm device within a second predefined time period;

wherein the alarm device generates a response signal of a first length of time when the alarm device detects the magnetic field at a first strength,

wherein the alarm device generates a response signal of a second length of time when the alarm device detects the magnetic field at a second strength,

wherein the first strength is different from the second strength and the first length of time is different from the second length of time; and

the generator generating an alarm signal to the operator of the vehicle and of sending a signal to shut down the vehicle, upon sensing a response signal of a predetermined strength.