US 5,635,887 AGranted

Compact rare earth magnet security switch assembly

AssigneeSentrol, Inc.

InventorsRobert G. Fischette, Scot R. Newport

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Abstract

A method and an apparatus employing a compact magnetic security switch for detecting the open or closed position of corresponding fixed frame and movable closure members, such as door and window assemblies, of entryways of buildings. The security switch assembly includes a high intrinsic coercive force rare earth, preferably neodymium, alloy magnet mountable on a movable closure member within a close clearance and within a predetermined gap and break distance of a switch mounted on a corresponding fixed frame member when in closed position, such that the electrical contacts interact with the magnet and thereby place the switch in a nonalarm position. The method of the present invention provides for mounting the rare earth alloy magnet without invading the subsurface structural integrity of the movable closure member. The rare earth alloy magnet has a generally flat configuration and is adaptable to unobtrusive and noninvasive shallow recess or surface mounting in tight-fitting structures having close clearances.

Claims22

Dependent claims

A method for providing a compact security switch in an assembly for detecting the open or closed position of a movable closure member relative to a fixed frame member, the security switch including a magnetic switch that is operatively attached to the fixed frame member and a magnet that is operatively attached to the movable closure member such that its subsurface structural integrity remains intact, the magnet being mountable within a close clearance of the fixed frame member and within a predetermined gap between the magnet and the magnetic switch, comprising:

providing the movable closure member configured for seating within the fixed frame member;
mounting on the movable closure member such that its subsurface structural integrity remains intact a rare earth alloy magnet characterized by an intrinsic coercive force exceeding about 7,000 oersteds;
and
mounting on the fixed frame member a magnetic switch having electrical contacts positioned along a switch axis such that the electrical contacts assume a first alarm state when the electrical contacts are axially aligned with the magnet within a predetermined gap between the magnet and the magnetic switch so as to interact with the magnetic field of the magnet when the movable closure member is in a closed position and that the electrical contacts assume a second alarm state when the movable closure member is opened and the magnet is moved past a predetermined break distance from the magnetic switch beyond which distance the electrical contacts do not interact with the magnetic field.

1 more element

Dependencies are inferred from the claim text.