TAMPER-RESISTANT ALARM SWITCH ASSEMBLY

• US 20100006408A1
• Filed: 07/14/2008
• Published: 01/14/2010
• Est. Priority Date: 07/14/2008
• Status: Active Grant

• Current Assignee: Magnasphere Corporation (discoverIE Group Plc)
• Original Assignee: Magnasphere Corporation (discoverIE Group Plc)
• Inventors: Woods, Randall
• Granted Patent: US 7,944,334 B2
• Time in Patent Office: Days
• US Class Current: 200/61.45M
• CPC Class Codes: H01H 36/0046 Limit switches, also fail-safe operation or anti-tamper considerations

Abstract

Tamper-resistant alarm switch assemblies (22, 100, 124, 148) are provided which include a first movement-sensing switch (24) and a second tamper-sensing switch assembly (25) including a switchable component (26) and an actuating component (74, 136, 166), mounted on a member (30) and each being switchable between respective first and second movement-sensing and tamper-sensing switch states in response to relative movement between first and second members (30, 32), and relative shifting between the switch (26) and actuating component (74, 136, 166). Mounting structure (28, 106, 138) is provided to attach the first switch (24) and second switch assembly (25) to the member (30) in a normal operating position wherein the first switch (24) will sense relative movement between the first and second members (30, 32), with relative shifting between the switchable component (26) and the actuating component (74, 136, 166) in the event of an attempted detachment of at least one of the components (26, 74, 136, 166) of the tamper switch assembly (25), or the first switch (24), or both thereof, from the member (30).

Claims

1. A tamper-resistant switch assembly operable to detect relative movement between first and second members, comprising:

a first movement-sensing switch mounted on one of said members and operable to switch between first and second separate movement-sensing states in response to relative movement between said first and second members;

a second tamper-sensing switch assembly mounted on said one member and including a switchable component and an actuating component, said switchable component and actuating component being relatively shiftable, said switchable component switchable between first and second tamper-sensing states in response to said relative shifting between the switchable and actuating components; and

mounting structure operable to attach said first switch and second switch assembly to said one member in a normal operating position wherein said first switch will sense said relative movement between said first and second members, and to cause said relative shifting between the switchable component and the actuating component of said tamper switch assembly, in the event of attempted detachment of at least one of the components of said second switch assembly, the first switch, or both thereof, from said normal operating position.

2. The assembly of claim 1, said first movement-sensing switch being a magnetically actuatable switch operable to switch between said first and second separate movement-sensing states in response to a change in magnetic field conditions adjacent the first movement-sensing switch.

3. The assembly of claim 2, including a first switch actuating component mounted on said other member and operable, in response to relative movement between the first and second members, to alter the magnetic field conditions adjacent the first movement-sensing switch so as to cause movement between said first and second separate movement-sensing states.

4. The assembly of claim 1, said first movement-sensing switch including a housing, at least one elongated, electrically conductive switch element extending into said housing, a shiftable body located within said housing and formed of electrically conductive material, and a second electrically conductive switch element, said body shiftable within the housing between a first position wherein the body is in electrical contact with both said first and second switch elements, and a second position wherein the body is not in contact with both said first and second switch elements.

5. The assembly of claim 1, said switchable component of said second tamper switch assembly being a magnetically actuatable switch operable to switch between said first and second separate tamper-sensing states in response to a change in magnetic field conditions adjacent said switchable component, said actuating component of said second tamper switch assembly located proximal to said switchable component.

6. The assembly of claim 5, said actuating component operable, in response to relative shifting between the switchable component and actuating component, to alter the magnetic field conditions adjacent the switchable component so as to cause a switch between said first and second tamper-sensing states.

7. The assembly of claim 1, said mounting structure comprising a first plate supporting said first movement-sensing switch, a second plate supporting one of said components of said second tamper switch assembly, said first and second plates secured to said one member.

8. The assembly of claim 7, there being threaded fasteners attaching said first and second plates to said one member.

9. The assembly of claim 7, said first switch and second switch assembly located within said first member and cooperatively configured such that detachment of the first or second plate, or both thereof, causes said relative shifting movement between said switchable component and said actuating component.

10. The assembly of claim 7, said second plate supporting said switchable component of said second tamper switch.

11. The assembly of claim 10, said first plate supporting said actuating component of said second tamper switch assembly.

12. The assembly of claim 7, said first plate secured to said one member by a first threaded fastener, said second plate secured to said one member by a second threaded fastener, said first plate being detachable from the first member separately from the second plate.

13. The assembly of claim 12, said second plate including an elongated arm extending from said second threaded fastener and having said tamper switch component supported thereon spaced laterally from the second threaded fastener such that detachment of the second threaded fastener will cause the second plate and switch component supported thereon to shift relative to the other component of the tamper switch.

14. The assembly of claim 1, said mounting structure comprising a single plate supporting said first switch and second switch assembly, there being a positioning element supported on the single plate and operable to hold one of the components of said tamper switch assembly in a first position corresponding to one of said tamper-sensing states, detachment of said single plate causing movement of said positioning element resulting in switching of the switchable component to the other of said tamper-sensing states.

15. The assembly of claim 14, said positioning element supporting said actuating component of said tamper switch assembly.

16. The assembly of claim 14, said positioning element comprising a threaded fastener extending through said single plate.

17. The assembly of claim 1, said first switch and one of the components of said second switch assembly supported together in a single enclosure, the other component of said second switch assembly supported adjacent said single enclosure.

18. The assembly of claim 17, said one component of said second switch assembly being said actuating component.

19. The assembly of claim 17, said other components of said second switch assembly supported on a housing, said enclosure received within said housing.

20. The assembly of claim 19, including a resilient element engaging said one element and said housing and biasing the housing toward the one element.

21. The assembly of claim 19, including a threaded fastener extending through said enclosure and received within a threaded opening of said housing.

22. The assembly of claim 19, said other component being said actuating component.

23. The assembly of claim 1, said second tamper switch switchable component selected from the group consisting of a reed switch, Hall effect switch, micro switch, a magnetic side switch, and magnetic ball switch.