Magnetic locking methods and apparatus

• US 4,287,512 A
• Filed: 03/31/1980
• Issued: 09/01/1981
• Est. Priority Date: 03/31/1980
• Status: Expired due to Term

• Current Assignee: Von Duprin Inc. (Allegion PLC)
• Original Assignee: Dynametric, Inc.
• Inventors: Combs, C. Marlon
• Primary Examiner(s): Swann, III, Glen R.
• Application Number:
  US06/136,012
• Time in Patent Office: 519 Days
• Field of Search: 340/542, 340/547, 340/687, 340/685, 340/540, 73/DIG. 3, 324/260, 324/251, 361/143, 361/144, 361/145
• US Class Current: 340/542
• CPC Class Codes: E05B 2047/0092 including means for preventing manipulation by an external magnetic field, e.g. preventing opening by using a strong magnet
• CPC Class Codes: E05C 19/166 electromagnetic
• CPC Class Codes: G08B 13/06 by tampering with fastening
• CPC Class Codes: Y10S 73/03 Hall effect

Abstract

Matching components of a magnetic locking assembly are magnetically attracted into mating relationship until a predetermined magnetic flux is established in one of the components. Such established predetermined flux is monitored to detect locking power diminutions between the locking assembly components. External magnetic fields applied to the locking assembly in an attempt to counterfeit the mentioned predetermined magnetic flux may be detected and indicated for security reasons.

Claims

1. In a method of operating a magnetic locking assembly having matching first and second magnetizable components, the improvement comprising in combination the steps of:

magnetically attracting said first and second components into mating relationship whereby a predetermined magnetic flux is established in one of said components; and

monitoring said established predetermined flux to detect locking power diminutions between said components.

2. A method as claimed in claim 1, wherein:

said magnetic flux is switchable to an "off" condition for releasing one of said components from the other of said components; and

said monitoring responds to a switching of the magnetic flux to said "off" condition by signaling a locking power diminution between said components.

3. A method as claimed in claim 1, including the step of:

providing an alarm indication in response to a detected locking power diminution.

4. A method as claimed in claim 3, wherein:

said magnetic flux is switchable to an "off" condition for releasing one of said components from the other of said components; and

said alarm indication is inhibited in response to a switching of the magnetic flux to said "off" condition.

5. In a method of operating a magnetic locking assembly having matching first and second magnetizable components, the improvement comprising in combination the steps of:

providing a pair of magnetic pole faces in one of said components;

magnetically attracting said first and second components into mating relationship whereby a predetermined magnetic flux is established between said pole faces; and

monitoring said established predetermined flux between said pole faces to detect locking power diminutions between said components.

6. A method as claimed in claim 5, wherein:

said pole faces are auxiliary pole faces provided in said one component in addition to main pole faces on said one component facing the other of said components.

7. A method as claimed in claim 5 or 6, including the step of:

providing a magnetic isthmus in parallel to said pair of magnetic pole faces restricting said magnetic flux in magnitude.

8. A method as claimed in claim 7, including the step of:

monitoring said established predetermined flux by implementing a Hall effect between said pair of pole faces.

9. A method as claimed in claim 5, including the steps of:

providing said one component with a magnetic core including a leg having a main pole face facing the other of said components; and

providing said pair of pole faces in said leg.

10. A method as claimed in claim 9, wherein:

said pair of pole faces are provided in an area of said leg smaller than an entire cross-section of said leg.

11. A method as claimed in claim 5, 6, 9 or 10, including the step of:

monitoring said established predetermined flux by implementing a Hall effect between said pair of pole faces.

12. A method as claimed in claim 5, 6, 9 or 10, wherein:

the other of said components has a magnetic flux path discontinuity; and

said pair of magnetic pole faces is laterally offset from said discontinuity.

13. A method as claimed in claim 5, 6, 9 or 10, including the steps of:

providing a second pair of magnetic pole faces in said one component;

detecting a second magnetic flux occurring between said second pair of magnetic pole faces upon application of an external magnetic field to said one component; and

monitoring said detected second magnetic flux.

14. A method as claimed in claim 9, including the steps of:

providing in said magnetic core a second pair of magnetic pole faces;

detecting a second magnetic flux occurring between said second pair of magnetic pole faces upon application of an external magnetic field to said one component; and

monitoring said detected second magnetic flux.

15. In apparatus for operating a magnetic locking assembly having matching first and second magnetizable components, the improvement comprising in combination:

means for magnetically attracting said first and second components into mating relationship whereby a predetermined magnetic flux is established in one of said components; and

means coupled to said attracting means for monitoring said established predetermined flux to detect locking power diminutions between said components.

16. Apparatus as claimed in claim 15, wherein:

said attracting means include means for rendering said magnetic flux switchable to an "off" condition for releasing one of said components from the other of said components; and

said monitoring means include means responding to a switching of the magnetic flux to said "off" condition by signaling a locking power diminution between said components.

17. Apparatus as claimed in claim 15, including:

means connected to said monitoring means for providing an alarm indication in response to a detected locking power diminution.

18. Apparatus as claimed in claim 17, wherein:

said attracting means include means for rendering said magnetic flux switchable to an "off" condition for releasing one of said components from the other of said components; and

said alarm indication providing means include means for inhibiting said alarm indication in response to a switching of the magnetic flux to said "off" condition.

19. In apparatus for operating a magnetic locking assembly having matching first and second magnetizable components, the improvement comprising in combination:

a pair of magnetic pole faces in one of said components;

means for magnetically attracting said first and second components into mating relationship whereby a predetermined magnetic flux is established between said pole faces; and

means coupled to said attracting means for monitoring said established predetermined flux between said pole faces to detect locking power diminutions between said components.

20. Apparatus as claimed in claim 19, wherein:

said pole faces are auxiliary pole faces present in said one component in addition to main pole faces on said one component facing the other of said components.

21. Apparatus as claimed in claim 19 or 20, including:

means for restricting said magnetic flux in magnitude, including a magnetic isthmus in parallel to said pair of magnetic pole faces.

22. Apparatus as claimed in claim 21, wherein:

said monitoring means include a Hall-effect device between said pair of pole faces.

23. Apparatus as claimed in claim 21, wherein:

said monitoring means include a pair of oppositely oriented Hall-effect devices between said pair of pole faces.

24. Apparatus as claimed in claim 19, wherein:

said one component has a magnetic core including a leg having a main pole face facing the other of said components, and having said pair of pole faces located therein at a distance from said main pole face.

25. Apparatus as claimed in claim 24, wherein:

said pair of pole faces extend over an area of said leg smaller than an entire cross-section of said leg.

26. Apparatus as claimed in claim 19, 20, 24 or 25, wherein:

said monitoring means include a Hall-effect device between said pair of pole faces.

27. Apparatus as claimed in claim 19, 20, 24 or 25, wherein:

said monitoring means include a pair of oppositely oriented Hall-effect devices between said pair of pole faces.

28. Apparatus as claimed in claim 19, 20, 24 or 25, wherein:

the other of said components has a magnetic flux path discontinuity; and

said pair of magnetic pole faces is laterally offset from said discontinuity.

29. Apparatus as claimed in claim 19, 20, 24 or 25, including:

a second pair of magnetic pole faces in said one component;

means for detecting a second magnetic flux occurring between said second pair of magnetic pole faces upon application of an external magnetic field to said one component; and

means connected to said detecting means for monitoring said detected second magnetic flux.

30. Apparatus as claimed in claim 24, including:

a second pair of magnetic pole faces in said magnetic core;

means for detecting a second magnetic flux occurring between said second pair of magnetic pole faces upon application of an external magnetic field to said magnetic core; and

means connected to said detecting means for monitoring said detected second magnetic flux.