Patent ID: 7218194

Claim:
A magnetic switching device for detecting relative movement between a first and a second member comprising: a switch assembly for mounting to the first member, the switch assembly including: a first switch element and a second switch element, said second switch element positioned apart from said first switch element; an electrically conductive shiftable body; a first attractive component; a flux director positioned in proximity to said shiftable body; said shiftable body movable between a first position where the shiftable body is in simultaneous contact with said first and second switch elements, and a second position where said shiftable body is out of simultaneous contact with said first and second switch elements; a second attractive component for mounting to said second member; said flux director providing a reduced reluctance path for an applied magnetic field and directing at least a portion of a magnetic field emanating therefrom toward said switch assembly; said first and second attractive components being positioned such that when the first and second members are in proximity to each other in a proximal position, said magnetic flux directing device allows a threshold level of magnetic flux to be applied to said shiftable body so that said shiftable body is moved to one of the first or second positions, and when the first and second members are moved out of proximity to each other in a distal position, said shiftable body is moved to the other of the first or second positions; and a magnetically permeable shim positioned adjacent to and extending at least partially around said shiftable body, said magnetically permeable shim coupling at least a portion of the applied magnetic field from said flux director to said shiftable body.