| 摘要 |
<p>PCT No. PCT/GB90/00576 Sec. 371 Date Dec. 5, 1991 Sec. 102(e) Date Dec. 5, 1991 PCT Filed Apr. 17, 1990 PCT Pub. No. WO90/13180 PCT Pub. Date Nov. 1, 1990.A safety switch having first and second elements intended to be mounted on components of a safety enclosure that are moveable relative to one another. The first and second elements are in a predetermined relative position adjacent each other when the enclosure is in a closed condition and spaced apart when the enclosure is in an open condition. A source of magnetic flux is mounted on one element and a magnetically operable switch is mounted on the other element. The magnetically operable switch is arranged so as to be switched by the magnetic flux generated by the source when the elements are moved adjacent to each other. A pair of tuned circuits are mounted one in each of the elements, and a switching circuit is connected to one of the tuned circuits. The switching circuit is arranged so as to be switched when the elements are moved adjacent to each other. An output circuit indicates that the enclosure is not closed unless both the magnetically operable switch and the switching circuit indicate that the two elements are adjacent to each other.</p> |
