Two-state Hall element proximity sensor device with lamp indicator

Claim 1

A proximity sensor kit having two basic component parts capable of being mounted to a fixed and a movable member of a machine, respectively, for producing an electrical output signal and a visual indication when a portion of said movable member moves to within a predetermined distance with respect to a portion of said fixed member, said kit comprising the combination of said parts, namely: (a) a two-state Hall element proximity sensor device, adapted to be mounted to said fixed member portion, comprising a Hall element and a voltage-threshold detector means being connected to the output of said Hall element for generating a particular electrical signal only when the magnetic field at said element exceeds a predetermined magnitude in a predetermined polarity; a housing containing said sensor device, the plane of said element being positioned parallel to and adjacent to an outer face of said housing; and an indicator lamp means for providing one state of illumination only when excited by said signal, said lamp means including a lamp that is connected to the output of said detector means and is attached to and protrudes from another face of said housing to be seen from many directions of viewing and to provide visual indication whether said particular electrical signal is present; (b) a magnet adapted to be mounted to said movable member portion in such a position that when said fixed portion is within said predetermined distance, one of the poles of said magnet substantially faces said sensor, said magnet providing an ambient magnetic field at said Hall element of said predetermined polarity and of said predetermined magnitude.