Alarm switch

Abstract

A magnetic switch apparatus ( 10 ) detects relative movement between first ( 12 ) and second ( 14 ) members and defeats attempted external magnetic manipulation of the apparatus. A rod-shaped, first switch element ( 20 ) is positioned transverse to and centrally aligned with a convex, second switch element ( 22 ) and spaced therefrom. A ring-shaped first magnet ( 26 ) is positioned about the first switch element ( 20 ) and spaced from the second element ( 22 ) in order to pull a ferromagnetic body ( 24 ) into a switch-open position out of contact with the second switch element ( 22 ) with these components mounted to the first member ( 12 ). A second magnet ( 18 ) mounted to the second member ( 14 ) is positioned and magnetically sufficient to pull the body ( 24 ) into a switch-closed position in contact with both of the switch elements ( 20, 22 ) when the members ( 12, 14 ) are in an adjacent position.

1. A magnetic switch apparatus for detecting relative movement between first and second members, said apparatus comprising:
 a switch assembly for mounting to the first member, said assembly including  
 a first switch element presenting a generally rod-shaped configuration,  
 a second switch element presenting a generally disc-shaped configuration and having a contact surface,  
 structure positioning said first switch element generally transverse to said contact surface and spaced therefrom,  
 a ferromagnetic body shiftable between a switch-open position in which said body is out of contact with both of said first and second elements and a switch-closed position in which said body is in electrical contact with both said element and said contact surface; and  
 a first magnet spaced from said contact surface and positioned for magnetically shifting said body to said switch-open position; and  
 a second magnet for mounting to the second member and positioned on an opposed side of said contact surface relative to said first switch element, said second magnet being magnetically sufficient for shifting said body to said switch-closed position when the members are in an adjacent position, and for allowing said first magnet to shift said body to said switch-open position when the members are separated.  
 
     
     
       2. The apparatus as set forth in  claim 1 , said contact surface presenting a generally convex configuration relative to said first switch element. 
     
     
       3. The apparatus as set forth in  claim 2 , said contact surface presenting a generally reversed conically shaped configuration. 
     
     
       4. The apparatus as set forth in  claim 1 , said contact surface presenting a central axis with said first switch contact generally aligned with said axis. 
     
     
       5. The apparatus as set forth in  claim 1 , said second switch element including a side wall circumscribing said contact surface as a bottom wall. 
     
     
       6. The apparatus as set forth in  claim 5 , said second switch element being integrally formed of metal. 
     
     
       7. The apparatus as set forth in  claim 6 , said switch assembly including an electrically insulating top wall spaced from said contact surface and circumscribed by said bottom wall to define a switching chamber containing said body. 
     
     
       8. The apparatus as set forth in  claim 7 , said first switch element including an extended portion extending outwardly through said top wall. 
     
     
       9. The apparatus as set forth in  claim 8 , said first magnet being ring-shaped and positioned adjacent said top wall and surrounding said extended portion. 
     
     
       10. The apparatus as set forth in  claim 9 , said body presenting a generally spherical configuration. 
     
     
       11. The apparatus as set forth in  claim 1 , said body presenting a generally spherical configuration. 
     
     
       12. The apparatus as set forth in  claim 1 , said switch-open position being an electrically open switch position, said switch-closed position being an electrically closed switch position. 
     
     
       13. The apparatus as set forth in  claim 1 , said switch elements being located so that said body shifts to a switch-open position when the members are in the adjacent position and when an external magnet is applied in the vicinity of the first member in an attempt to manipulate magnetically said apparatus. 
     
     
       14. A magnetic switch apparatus for detecting relative movement between first and second members, said apparatus comprising:
 a switch assembly for mounting to the first member, said assembly including  
 a first switch element presenting a generally rod-shaped configuration,  
 a second switch element presenting a generally disc-shaped configuration and having a convex contact surface presenting a central axis  
 an electrically insulating top wall spaced from said contact surface, centrally receiving an extension portion of said first switch element therethrough, and positioning said first switch element generally aligned with said axis of said contact surface and spaced therefrom,  
 a ferromagnetic ball shiftable between a switch-open position in which said body is out of contact with both of said elements and a switch-closed position in which said body is in electrical contact with both said element and said contact surface, said switch-open position being an electrically open switch position, said switch-closed position being an electrically closed switch position, and  
 a ring-shaped, first magnet surrounding said extension portion and positioned for magnetically shifting said body to said switch-open position; and  
 a second magnet for mounting to the second member and positioned on an opposed side of said contact surface relative to said first switch element, said second magnet being sufficient magnetically for shifting said body to said switch-closed position when the members are in an adjacent position, and for allowing said first magnet to shift said body to said switch-open position when the members are separated.  
 
     
     
       15. An alarm system for activating an alarm upon shifting of first and second members from an adjacent position to a separated position and upon attempted manipulation by an external magnet of the alarm system when the members are in the adjacent position, said system comprising:
 a switch apparatus; and  
 an alarm control coupled with said switch apparatus and responsive to a change in state thereof for activating an alarm, said switch apparatus including  
 a switch assembly for mounting to the first member, said assembly including  
 a first switch element presenting a generally rod-shaped configuration,  
 a second switch element presenting a generally disc-shaped configuration and having a contact surface,  
 structure positioning said first switch element generally transverse to said contact surface and spaced therefrom,  
 a ferromagnetic body shiftable between a switch-open position in which said body is out of contact with both of said elements and a switch-closed position in which said body is in electrical contact with both said element and said contact surface,  
 a first magnet spaced from said contact surface and positioned for magnetically shifting said body to said switch-open position,  
 a second magnet for mounting to the second member and positioned on an opposed side of said contact surface relative to said first switch element, said second magnet being sufficient magnetically for shifting said body to said switch-closed position when the members are in an adjacent position, and for allowing said first magnet to shift said body to said switch-open position when the members are separated,  
 said switch elements being located so that said body shifts to a switch-open position when the members are in the adjacent position and when an eternal magnet is applied in the vicinity of the first member in an attempt to manipulate magnetically said apparatus.  
 
     
     
       16. A method of detecting the relative movement between first and second members from a close position where the members are adjacent, and an open position where the members are separated, said method comprising the steps of:
   installing a switch assembly on said first member, said switch assembly including a first elongated switch element, a second switch element disposed in spaced relationship to the first element and a ferromagnetic body located adjacent the first and second switch elements;        when said members are in said close position, using a magnetic field of sufficient strength to maintain the ferromagnetic body in a first switch orientation in simultaneous contact with said first and second switch elements;        in response to relative movement of the members from said close to said open position, magnetically shifting said ferromagnetic body to a second switch orientation out of contact with said second switch element; and        generating a signal when said ferromagnetic body is shifted.     
     
     
       17. The method of  claim 16 , including the further step of using a magnet located in said second member to provide said magnetic field of sufficient strength. 
     
     
       18. The method of  claim 16 , said first switch element being in a generally upright orientation, with said second switch element spaced below the first switch element, said maintaining step comprising the step of maintaining the ferromagnetic body in a lower first switch orientation, said magnetic shifting step comprising the step of shifting the ferromagnetic body upwardly to said second switch orientation. 
     
     
       19. The method of  claim 18 , including the step of shifting said body upwardly using a retraction magnet located above said first element. 
     
     
       20. The method of  claim 16 , said first switch element comprising an elongated, rod- like member.   
     
     
       21. The method of  claim 16 , said second switch element being generally disc- shaped.   
     
     
       22. The method of  claim 16 , said body being spherical in shape. 
     
     
       23. A magnetic switch apparatus for detecting relative movement between first and second members from a close position where the members are adjacent, and an open position where the members are separated, said apparatus comprising a switch assembly for mounting to the first member, including a first, elongated switch element and a second switch element in spaced relationship to said first switch element, and a magnet assembly including a ferromagnetic body adjacent said first and second switch elements, said assembly operable to shift said ferromagnetic body in a first switch orientation in simultaneous contact with said first and second switch elements when said members are in said close position, and to shift said ferromagnetic body to a second switch orientation out of contact with said second switch element in response to relative movement of the members to said open position. 
     
     
       24. The apparatus of  claim 23 , said body being spherical. 
     
     
       25. The apparatus of  claim 23 , said first switch element being generally rod- shaped in configuration.   
     
     
       26. The apparatus of  claim 23 , said second switch element being generally disc- shaped.   
     
     
       27. The apparatus of  claim 26 , said second switch element including a contact surface presenting a generally reversed conically shaped configuration. 
     
     
       28. The apparatus of  claim 23 , said magnet assembly further including a first magnet disposed above said first contact, and a second magnet for mounting to the second member. 
     
     
       29. The apparatus of  claim 23 , said first switch element being in a generally upright orientation, with said second switch element disposed below the first switch element. 
     
     
       30. A method of detecting the relative movement between first and second members from a close position where the members are adjacent, and an open position where the members are separated, said method comprising the steps of:
   installing a switch assembly on said first member, said switch assembly including a first elongated switch element, a second switch element disposed in spaced relationship to the first element, and a shiftable body movable between a first position in simultaneous contact with said first and second switch elements, and a second position out of said simultaneous contact;        when said members are in said close position, using a magnetic field of sufficient strength to maintain said body in one of said first and second positions;        in response to movement of the members from said close to said open position, magnetically moving the body to the other of said first and second positions; and        generating a signal when said body is moved.     
     
     
       31. The method of  claim 30 , said magnetic moving step comprising the steps of using a magnetic field developed between said body and a first cooperable component on said first member. 
     
     
       32. The method of  claim 31 , said first component comprising a ring- shaped magnet.   
     
     
       33. The method of  claim 30 , said magnetic field of sufficient strength being developed between said body and a second cooperable component on said second member. 
     
     
       34. The method of  claim 33 , said second component comprising a magnet mounted on said second member. 
     
     
       35. The method of  claim 30 , said first switch element being in a generally upright orientation, with said second switch element spaced below the first switch element, said maintaining step comprising the step of maintaining the ferromagnetic body in a lower first switch orientation, said magnetic moving step comprising the step of shifting the ferromagnetic body upwardly to said second switch orientation. 
     
     
       36. A method comprising the steps of:
   providing a switch assembly including a first elongated switch element, a second switch element disposed in spaced relationship to the first element and a shiftable body movable between a first position in simultaneous contact with said first and second switch elements, and a second position out of said simultaneous contact;        using a magnetic field of sufficient strength to maintain said body in one of said first and second positions; and        magnetically shifting the body to the other of first and second positions in response to a change of magnetic condition proximal to the switch assembly.     
     
     
       37. The method of  claim 36 , including the step of mounting said switch assembly on a first member, said change of condition comprising moving a second member relative to the first member. 
     
     
       38. The method of  claim 37 , said second member being equipped with a magnet, said magnetic moving step occurring by virtue of the magnetic attraction between said body and said second member magnet. 
     
     
       39. A switch assembly comprising:
   a first wall, a second wall, and a circumscribing side wall cooperatively defining a switch chamber;        a first switch element, at least portion of which extends into said switch chamber; and        a shiftable body located within said switch chamber; and        a component associated with one of said first or second walls;        said body and component cooperatively formed to be magnetically attractive so that the body is magnetically moved within said chamber by virtue of the presence of said component.     
     
     
       40. The switch assembly of  claim 39 , said second wall and said side wall comprising a second switch element. 
     
     
       41. The switch assembly of  claim 40 , said body being shiftable between a first position in simultaneous contact with said first and second switch elements and a second position out of said simultaneous contact. 
     
     
       42. The switch assembly of  claim 41 , said component comprising a magnet. 
     
     
       43. The switch assembly of  claim 42 , said body retained in said second position by virtue of the magnetic attraction between said body and said component and shiftable to said first position in response to a change of magnetic condition proximal to the switch assembly. 
     
     
       44. The switch assembly of  claim 39 , said first switch element presenting an elongated, rod- like configuration which is oriented in a substantially upright manner.   
     
     
       45. The switch assembly of  claim 39 , said component secured to said first wall.