Self-disengaging wearable grounding device

• US 20040196612A1
• Filed: 05/08/2003
• Published: 10/07/2004
• Est. Priority Date: 04/03/2003
• Status: Active Grant

• Current Assignee: Desco Industries Incorporated
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Kraz, Vladimir, Gurga, Fatjon, Martin, Kirk Alan, Kraz, Yelena
• Granted Patent: US 7,085,120 B2
• Time in Patent Office: Days
• US Class Current: 361/220
• CPC Class Codes: A61N 1/14 Leading-off electric charges, e.g. by earthing carrying-off electrostatic charges, in general H05F3/00

Abstract

The invention is a grounding device that grounds the wearer when the wearer is in a designated area and automatically disengages when the wearer leaves the designated area. In more detail, the grounding device includes a wristband that is electrically coupled to a grounded object with a fastening mechanism, wherein the fastening mechanism automatically releases to separate the wristband from the grounded object if the wristband is outside of the designated area. Where the fastening mechanism includes a coupling mechanism (e.g., a wire), there may be a rotating device that retracts the coupling mechanism after the fastening mechanism is released. The device may be enhanced with a grounding device monitoring unit that monitors whether the grounding device is in use and a sensor that detects whether the operator is in the designated area, so that an alarm is triggered if the operator is in the designated area and the grounding device is not in use.

Claims

1. A wearable grounding device that grounds a wearer, the grounding device comprising a wristband that is electrically coupled to a grounded object with a fastening mechanism, wherein the fastening mechanism automatically releases to separate the wristband from the grounded object in response to a force applied to the fastening mechanism.

2. The device of claim 1, wherein the fastening mechanism comprises a magnetic mating structure and a ferromagnetic fixing mechanism that releasably couple to each other.

3. The device of claim 1, wherein the fastening mechanism comprises a magnetic material partially surrounded by a first conductive ring, wherein the magnetic material releasably couples to a ferromagnetic material that is partially surrounded by a second conductive ring so that the first and the second conductive rings contact each other;

and

a coupling mechanism connected to at least one of the first and the second conductive rings.

4. The device of claim 3 further comprising:

a third conductive ring arranged concentrically with the first conductive ring and electrically separated from the first conductive ring;

a fourth conductive ring arranged concentrically with the second conductive ring and electrically separated from the second conductive ring so that the third conductive ring and the fourth conductive ring contact each other when the magnetic material attaches to the ferromagnetic material, wherein the third conductive ring and the fourth conductive ring become electrically coupled if the wristband properly contacts the wearer; and

a second coupling mechanism connected to at least one of the third and the fourth conductive rings.

5. The device of claim 1, wherein the fastening mechanism comprises:

a coupling mechanism with a magnetic mating structure attached to at least one end; and

a ferromagnetic surface to which the magnetic mating structure is releasably connected.

6. The device of claim 5, wherein the magnetic mating structure detaches from the ferromagnetic device if a tension level in the coupling mechanism exceeds a threshold value.

7. The device of claim 1, wherein the fastening mechanism comprises:

a coupling mechanism with a ferromagnetic fixing mechanism attached to at least one end; and

a magnetic mating structure to releasably connected to the ferromagnetic fixing mechanism.

8. The device of claim 7, wherein the magnetic properties of the magnetic mating structure is such that the magnetic mating structure detaches from the ferromagnetic fixing mechanism if a tension level in the cable exceeds a threshold value.

9. The device of claim 1, wherein one of the grounded object and the wristband is integrated with the fastening mechanism.

10. The device of claim 1, wherein the fastening mechanism comprises a Velcro®

-type fastening mechanism including a hook-type mating structure that releasably couples to a loop-type fixing mechanism.

11. The device of claim 1, wherein the fastening mechanism comprises a spring-release fixing mechanism and a mechanical mating structure that are releasably coupled to each other.

12. The device of claim 1, wherein the wristband is electrically coupled to the grounded object with a coupling mechanism that is retracted in by a rotating device if the fastening mechanism is released.

13. The device of claim 12, wherein the rotating device is integrated with the wristband.

14. The device of claim 12, wherein the rotating device comprises a pulley that translates a first force exerted by a weight at one end of the coupling mechanism into a retraction of the coupling mechanism.

15. A wearable grounding device that grounds a wearer, the grounding device comprising:

a wristband that makes electrical contact with the wearer, the wristband having a first coupling mechanism that extends from the wristband; and

a connector that electrically couples to the first coupling mechanism and a second coupling mechanism extending from a grounded object, wherein the connector attaches to a belt.

16. The device of claim 15, wherein at least one of the first and second coupling mechanisms couple to the connector in a releasable manner.

17. The device of claim 15, wherein the first coupling mechanism includes a wire, further comprising a garter for keeping the first coupling mechanism close to the wristband wearer.

18. A system for grounding an operator, the system comprising:

a wristband; and

a grounded object that is electrically connected to the wristband with a fastening mechanism that includes a coupling mechanism, wherein the fastening mechanism releases to separate the wristband from the grounded object if a tension level in the coupling mechanism exceeds a threshold level.

19. The system of claim 18 wherein a first end of the coupling mechanism is attached to a mating structure and a second end of the coupling mechanism is attached to a weight, the system further comprising:

a wall having a hole through which the coupling mechanism extends so that the weight and the mating structure are located on different sides of the wall; and

a rotating device located to pull the coupling mechanism toward the wall when the fastening mechanism is released, in response to a force exerted by the weight at the second end of the coupling mechanism, until the mating structure contacts the wall.

20. The system of claim 18, further comprising a rotating device that retracts the coupling mechanism after the fastening mechanism is released.

21. The system of claim 20, wherein the rotating device maintains a constant level of tension in the coupling mechanism, the rotating device further comprising a latch that prevents the coupling mechanism from being retracted when the fastening mechanism is not released.

22. The system of claim 20, wherein the rotating device comprises a spring-loaded spool.

23. The system of claim 20, wherein the rotating device is driven by an electric motor.

24. The system of claim 19 wherein the grounded object is a part of the rotating device and the mating structure is electrically connected to the grounded object through the coupling mechanism, the system further comprising:

an electrically conductive section of the wall that is separated from the hole by an insulating region, wherein the electrically conductive section is located to contact the mating structure only when the mating structure contacts the wall; and

a grounding device monitoring unit that monitors a voltage difference between the grounded object and the electrically conductive section to determine whether the wristband is grounded.

25. The system of claim 24 further comprising a proximity sensing unit for sensing whether the wristband is in a designated area.

26. The system of claim 25 wherein the proximity sensing unit comprises at least one of:

an infrared motion detector, an infrared proximity sensor, a microwave proximity detector, an ultrasonic proximity detector, a light barrier, and a mechanical detecting means.

27. The system of claim 25 wherein the proximity sensing unit comprises a sensitivity adjustment mechanism.

28. The system of claim 25 further comprising a logic circuit that receives input from both the grounding device monitoring unit and the proximity sensing unit and triggers an alarm 20 only if the proximity sensing unit indicates that the wristband is in the designated area and the grounding device monitoring unit indicates that the wristband is not grounded.

29. The system of claim 28 wherein the alarm comprises a sequence of signals that are activated at a preset frequency, further comprising a circuit for changing the frequency.

30. The system of claim 28 further comprising a facility monitoring system interface unit for logging the alarm in a facility database if the proximity sensing unit indicates that the wristband is in the designated area and the grounding device monitoring unit indicates that the wristband is not grounded.

31. The system of claim 25 further comprising an equipment interface unit for disabling an equipment if the proximity sensing unit indicates that the wristband is in the designated area and the grounding device monitoring unit indicates that the wristband is not grounded.

32. The system of claim 25 further comprising a time delay unit for delaying a triggering of the alarm by a predetermined grace period.

33. The system of claim 25 further comprising a static voltage detection mechanism.

34. A system for grounding an operator, the system comprising a proximity sensing unit for sensing operator presence in a designated area, the proximity sensing unit enabling a grounding device monitoring unit and a logic circuit in response to sensing operator presence, wherein the grounding device monitoring unit monitors whether the operator is electrically grounded and the logic circuit triggers an alarm if the proximity sensing unit indicates that the operator is in the designated area and the grounding device monitoring unit indicates that the wristband is not grounded.

35. The system of claim 34 wherein the proximity sensing unit comprises at least one of:

an infrared motion detector, an infrared proximity sensor, a microwave proximity detector, an ultrasonic proximity detector, a light barrier, and a mechanical detecting means.

36. The system of claim 34 wherein the proximity sensing unit comprises a sensitivity adjustment mechanism.

37. The system of claim 36 wherein the sensitivity adjustment mechanism comprises one of a means for continuous adjustment and a switch.

38. The system of claim 37 wherein the alarm comprises a sequence of signals that are activated at a preset frequency, further comprising a circuit for changing the frequency.

39. The system of claim 37 further comprising a facility monitoring system interface unit for logging the alarm in a facility database if the proximity sensing unit indicates that the wristband is in the designated area and the grounding device monitoring unit indicates that the operator is not grounded.

40. The system of claim 34 further comprising an equipment interface unit for disabling an equipment if the proximity sensing unit indicates that the operator is in the designated area and the grounding device monitoring unit indicates that the operator is not grounded.

41. The system of claim 34 further comprising a time delay unit for delaying a triggering of the alarm by a predetermined grace period.

42. The system of claim 34 further comprising a static voltage detection mechanism.

43. A method of grounding an operator, the method comprising electrically coupling a wristband to a grounded object with a fastening mechanism that includes a coupling mechanism, wherein the fastening mechanism automatically disengages when a tension level in the coupling mechanism exceeds a threshold level.

44. The method of claim 43, wherein electrically coupling the wristband to the grounded object comprises attaching a magnetic mating structure to a ferromagnetic fixing mechanism.

45. The method of claim 43, wherein electrically coupling the wristband to the grounded object comprises mechanically mating a mating structure with a spring-release fixing mechanism.

46. The method of claim 43 further comprising retracting the coupling mechanism with a rotating device when the fastening mechanism is released.

47. The method of claim 46 further comprising:

monitoring a voltage difference between the grounded object and another object that becomes grounded only when the coupling mechanism is retracted; and

determining that the wristband is not grounded when the voltage difference is approximately zero.

48. The method of claim 47 further comprising:

sensing whether the wristband is in a designated area; and

triggering an alarm if the wristband is in the designated area and the voltage difference is approximately zero.

49. The method of claim 48 wherein the alarm comprises a sequence of signals released at a predetermined frequency, further comprising changing the frequency.

50. The method of claim 48 further comprising waiting a predetermined period of time before triggering the alarm.

51. The method of claim 48 further comprising disabling an equipment if the wristband is not grounded.

52. The method of claim 43 further comprising:

connecting the wristband to the grounded object with a first coupling mechanism and a second coupling mechanism, wherein the first coupling mechanism and the second coupling mechanisms are electrically connected to each other only if the wristband is worn properly to allow both coupling mechanisms to electrically connect to the wearer; and

monitoring electrical continuity between the first and the second coupling mechanisms to determine if the wristband is worn properly.

53. A method of grounding an operator, the method comprising:

sensing operator presence in a designated area;

if the operator is present in the designated area, monitoring a wristband to determine whether the operator is electrically grounded; and

triggering an alarm if the operator is not grounded.