Method and apparatus for detecting container movement by a crane

• US 20080036603A1
• Filed: 04/02/2007
• Published: 02/14/2008
• Est. Priority Date: 08/14/2006
• Status: Active Grant

• Current Assignee: Savi Technology Incorporated
• Original Assignee: Savi Technology Incorporated
• Inventors: Hilliker, Stephen E., Chan, Joseph S., Cargonja, Nikola, Nardelli, Albert, Brand, Timothy K.
• Granted Patent: US 8,264,331 B2
• Time in Patent Office: Days
• US Class Current: 340/572.4
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A tag can receive first and second wireless signals respectively defining first and second transmission fields that overlap. When the tag moves from the first field to the second field through the region of overlap, the apparatus transitions only once from recognizing the tag is in the first field to recognizing the tag is in the second field. According to another aspect, first and second signposts are supported at spaced locations in the region of a crane, and respectively transmit first and second wireless signals that are different, and that respectively define first and second fields of transmission. According to yet another aspect, a signpost transmits wireless signals having a transmission field, and a system senses positional information regarding a tag movable relative to the signpost, the system using the positional information to determine a location of the tag in relation to the transmission field.

Claims

1. An apparatus comprising a tag that can receive first and second wireless signals respectively defining first and second fields of transmission that overlap, wherein when said tag is moving from the first field to the second field through the region of overlap, said apparatus transitions only once from recognizing that said tag is in the first field to recognizing that said tag is in the second field.

2. An apparatus according to claim 1, wherein said tag carries out the determination of when to transition from recognizing that said tag is in the first field to recognizing that said tag is in the second field.

3. An apparatus according to claim 1,

wherein said tag can transmit further wireless signals containing information that is a function of the first and second wireless signals;

and

including a system having a reader that can receive said further wireless signals, and having structure for sensing positional information regarding said tag, said system carrying out the determination of when to transition from recognizing that said tag is in the first field to recognizing that said tag is in the second field, as a function of the positional information and the further wireless signals.

4. An apparatus according to claim 1, including:

first and second signposts that are spaced and that respectively transmit the first and second wireless signals; and

a system having structure for sensing positional information regarding said tag, said system selectively enabling and disabling said first and second signposts as a function of the positional information.

5. An apparatus according to claim 4, wherein said first and second wireless signals transmitted by said signposts are near field signals of primarily magnetic character.

6. An apparatus according to claim 1, wherein said apparatus uses a hysteresis technique to determine when to transition from recognizing that said tag is in the first field to recognizing that that said tag is in the second field.

7. An apparatus according to claim 1, wherein when said tag first receives one of the second wireless signals, said apparatus delays for a time interval before making a determination of whether said tag has moved from the first field to the second field.

8. An apparatus according to claim 1, wherein said apparatus determines which of the first and second fields said tag is currently in as a function of the relative received strengths of the first and second wireless signals.

9. An apparatus according to claim 1, wherein said apparatus assigns a high priority to one of the first and second wireless signals and a low priority to the other thereof, said apparatus recognizing one of the low priority wireless signals if none of the high priority wireless signals are subsequently received during a selected time interval.

10. An apparatus according to claim 1, wherein said apparatus assigns a high priority to one of the first and second wireless signals and a low priority to the other thereof, said apparatus recognizing one of the low priority wireless signals if a selected number of the low priority wireless signals are consecutively received without intervening receipt of any of the high priority signals.

11. An apparatus according to claim 1, including:

a crane; and

first and second signposts that are supported on said crane at spaced locations, and that respectively transmit the first and second wireless signals.

12. A method of operating an apparatus having a tag that can receive first and second wireless signals respectively defining first and second fields of transmission that overlap, comprising:

transitioning only once from recognizing that said tag is in the first field to recognizing that said tag is in the second field when said tag is moving from the first field to the second field through the region of overlap.

13. A method according to claim 12, including:

causing said tag to transmit further wireless signals containing information that is a function of the first and second wireless signals; and

causing a system separate from said tag to receive the further wireless signals and to sense positional information regarding said tag, and to carry out the determination of when to transition from recognizing that said tag is in the first field to recognizing that said tag is in the second field, as a function of the positional information and the further wireless signals.

14. A method according to claim 12, including causing a system separate from said tag to sense positional information regarding said tag, and to selectively enable and disable transmission of said first and second wireless signals as a function of the positional information.

15. A method according to claim 12, including responding to first receipt by said tag of one of the second wireless signals by delaying for a time interval before making a determination of whether said tag has moved from the first field to the second field.

16. A method according to claim 12, including determining which of the first and second fields said tag is currently in as a function of the relative received strengths of the first and second wireless signals.

17. A method according to claim 12, including:

assigning a high priority to one of the first and second wireless signals and a low priority to the other thereof; and

recognizing one of the low priority wireless signals if none of the high priority wireless signals are subsequently received during a selected time interval.

18. A method according to claim 12, including:

assigning a high priority to one of the first and second wireless signals and a low priority to the other thereof; and

recognizing one of the low priority wireless signals if a selected number of the low priority wireless signals are consecutively received without intervening receipt of any of the high priority signals.

19. An apparatus comprising:

a crane; and

first and second signposts supported at spaced locations in the region of the crane, said first and second signposts respectively transmitting first and second wireless signals that are different and that respectively define first and second fields of transmission.

20. An apparatus according to claim 19, wherein said first and second signposts are supported on said crane at vertically spaced locations.

21. An apparatus according to claim 20, including structure cooperable with said first and second signposts for synchronizing operation thereof so that the first wireless signals are not transmitted simultaneously with the second wireless signals, and so that the second wireless signals are not transmitted simultaneously with the first wireless signals.

22. An apparatus according to claim 20,

wherein said crane has first and second portions, said first portion being supported for movement relative to said second portion thereof;

and

wherein said first and second signposts are respectively supported on said first and second portions of said crane.

23. An apparatus according to claim 22, including structure responsive to movement of said first portion relative to said second portion and cooperable with said first signpost for causing suppression of transmission of the first wireless signals by said first signpost when said first portion moves to a selected operational position relative to said second portion.

24. An apparatus according to claim 19, including a system having a reader that is supported in the region of said crane and that can receive further wireless signals different from the first and second wireless signals.

25. An apparatus according to claim 24, including a tag disposed on an object supported and moved by said crane, wherein said tag can receive the first and second wireless signals, and can transmit the further wireless signals.

26. An apparatus according to claim 25, wherein said system includes structure for sensing positional information regarding said tag, and for selectively disabling at least one of said first and second signposts as a function of said positional information.

27. An apparatus according to claim 19, wherein said first and second wireless signals transmitted by said signposts are near field signals of primarily magnetic character.

28. A method comprising:

transmitting first and second wireless signals that are different from respective spaced first and second locations in the region of a crane, said first and second wireless signals respectively defining first and second fields of transmission.

29. A method according to claim 28, including selecting said first and second locations to be vertically spaced.

30. A method according to claim 29, including synchronizing transmission of said first and second wireless signals so that the first wireless signals are not transmitted simultaneously with the second wireless signals, and so that the second wireless signals are not transmitted simultaneously with the first wireless signals.

31. A method according to claim 29, including:

selecting said first and second locations to respectively be on first and second portions of said crane that are supported for movement relative to each other; and

suppressing transmission of the first wireless signals when said first portion moves to a selected operational position relative to said second portion.

32. A method according to claim 28, including:

providing a tag on an object supported and moved by said crane;

causing said tag to receive the first and second wireless signals, and to transmit further wireless signals that are different from the first and second wireless signals;

sensing positional information regarding said tag; and

selectively disabling transmission of at least one of said first and second wireless signals as a function of said positional information.

33. An apparatus comprising:

a signpost that transmits wireless signals having a transmission field;

a tag that can move relative to the signpost, and that can receive the wireless signals transmitted by the signpost when said tag is within said transmission field; and

a system having structure for sensing positional information regarding said tag, said system using said positional information to determine a location of said tag in relation to said transmission field.

34. An apparatus according to claim 33, further including a crane, said signpost being supported in the region of said crane.

35. An apparatus according to claim 33, wherein said system influences operation of said signpost as a function of said positional information regarding said tag.

36. A method comprising:

transmitting wireless signals having a transmission field;

sensing positional information regarding a tag that can move relative to the transmission field, and that can receive the wireless signals when said tag is within said transmission field; and

using said positional information to determine a location of said tag in relation to said transmission field.

37. An apparatus according to claim 36, including influencing said transmitting of said wireless signals as a function of said positional information regarding said tag.