DISPLACEMENT DETECTING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a highly reliable sensor by extending lifetime of a battery and a circuit. SOLUTION: A first case 31 has a reed switch 7 built-in. A second case 32 has a permanent magnet 10 operating the reed switch 7 built-in. The first case 31 and the second case 32 are engaged so as to be engaged under normal conditions while separated when a specified tensile force acts between both cases. The reed switch 7 is turned off under engaging condition of the first case 31 and the second case 32, and the permanent magnet 10 makes the reed switch turn on by detaching from the reed switch when the first case 31 and the second case 32 are separated from each other.