Latch Monitoring Apparatus for a Shipping Container Door

• US 20090102649A1
• Filed: 10/16/2008
• Published: 04/23/2009
• Est. Priority Date: 10/19/2007
• Status: Active Grant

• Current Assignee: N7 Systems, LLC
• Original Assignee: N7 Systems, LLC
• Inventors: Keller, John R., Montrose, Rodney C., Diener, Mark A.
• Granted Patent: US 8,138,917 B2
• Time in Patent Office: Days
• US Class Current: 340/542
• CPC Class Codes: E05B 2047/0097 including means for monitoring voltage, e.g. for indicating low battery state
• CPC Class Codes: E05B 45/06 Electric alarm locks E05B45/005 takes precedence
• CPC Class Codes: E05B 83/10 Rotary bars
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders
• CPC Class Codes: G08B 13/08 by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind
• CPC Class Codes: Y10T 292/31 Hasps
• CPC Class Codes: Y10T 292/51 Seal bolts

Abstract

A system, method, and apparatus for monitoring and detecting movement of components of a shipping container latch. A latch monitor may embody an electromagnetic sensing unit and a nearby magnet or light emitter for measuring and characterizing the profile of a nearby electromagnetic field. The field profile is monitored to detect a change in the profile, log the change, and report any abnormal disturbance to the electromagnetic field, indicating a breach of the integrity of a latching mechanism on a shipping container. An alert of a breach event may be sent via a communication network to an authority for response. The invention can distinguish authorized, incidental, and tampering events, and also store and upload an electronic manifest for a shipping container.

Claims

1. A latch monitor for a container door, comprising:

a magnet attached to a moving portion of a latch mechanism attached to said container door; and

an array of magnetic sensors disposed in fixed positions relative to a stationary portion of said latch mechanism and proximate a path traversed by said magnet.

2. The apparatus of claim 1, further comprising:

a memory for storing data provided by said magnetic sensors corresponding to relative positions of said magnet with respect to said array of magnetic sensors; and

a processor operative according to an executable program for analyzing said data to distinguish tampering events from a secured indication of said latch mechanism.

3. The apparatus of claim 1, wherein said magnet comprises a bar magnet having a north pole and a south pole aligned along a common, substantially straight axis.

4. The apparatus of claim 3, wherein said magnet is aligned substantially along a radial line extending from a longitudinal centerline of a rotating member of said latch mechanism such that an outermost one of said north and south poles swings in an arc as said rotating member is rotated between predetermined closed and open states of said latch mechanism.

5. The apparatus of claim 1, wherein said array of magnetic sensors comprises a set of Hall Effect Sensor (HES) elements arranged in a predetermined fixed configuration.

6. The apparatus of claim 1, wherein said array of magnetic sensors is enclosed in a housing disposed in a fixed relationship to said stationary portion of said latch mechanism.

7. The apparatus of claim 1, wherein said stationary portion of said latch mechanism includes an exterior surface of said door of said container.

8. The apparatus of claim 1, wherein said moving portion of said latch mechanism includes a rotating member attached to said door of said container.

9. The apparatus of claim 1, comprising:

a magnetic signature produced by said array of magnetic sensors representing a magnetic field profile corresponding to said latch mechanism being in a defined state of said latch.

10. The apparatus of claim 9, wherein said magnetic signature comprises:

a set of magnetic sensor output signal values that characterize said magnetic field profile for the defined state of said latch produced by each of the magnetic sensors in the array and stored in a corresponding set of memory locations.

11. The apparatus of claim 9, wherein said defined state of said latch is selected from the group consisting of closed and latched, closed but not latched, partially open, and open.

12. The apparatus of claim 2, wherein said memory comprises:

a first memory segment having stored therein a magnetic signature established by said array of magnetic sensors corresponding to said latch mechanism being in a secured state.

13. The apparatus of claim 12, wherein said magnetic signature comprises:

a set of magnetic sensor output signal values for the secured state of said latch produced by the magnetic sensors in the array.

14. The apparatus of claim 2, wherein said processor comprises:

a mechanism for periodically comparing a set of magnetic sensor output signal values with a magnetic signature representing a reference state of said latch mechanism.

15. The apparatus of claim 14, wherein said reference state of said latch mechanism corresponds to a closed-and-latched latch mechanism.

16. The apparatus of claim 2, wherein said processor comprises:

at least one detection threshold stored in said memory for distinguishing said tampering events from authorized operations and from incidental events involving said container latch mechanism.

17. The apparatus of claim 16, wherein each said detection threshold comprises:

a set of averaged sensor output signals determined during a calibration operation with said latch mechanism in a secured condition.

18. The apparatus of claim 2, wherein said latch monitor comprises:

a set of detection zones defined proximate and relative to said sensor array through which said magnet may move for locating the position of said magnet as said rotating member of said latch mechanism is rotated through its range of positions.

19. The apparatus of claim 18, wherein said set of detection zones comprises:

a series of defined regions defined along a circular arc centered on the rotation axis of said rotating member of said latch mechanism and disposed within plus and minus 90 degrees relative to a zero degree reference with the center of said array of sensors.

20. A latch monitor for a container door, comprising:

an array of magnetic sensors disposed in fixed positions relative to a stationary portion of a latch mechanism attached to said container door and proximate a path traversed by a magnet disposed on an adjacent moving portion of said latch mechanism.