PURPOSE: To obtain a detector to detect whether a person is sitting on a chair or not which detects with high precision without making detection mistakes even when the person sits on a seating surface unevenly or not in good posture, needs no reformation of the chair itself and has a long life.
CONSTITUTION: On a base 1 having an engaging part 6, with which either a foreleg 10 or a rearleg 5 of a chair 9 or both of them are engaged, a plate spring 8 to support the foreleg 10 or the rearleg 5 of the chair 9 is mounted by fixing its base end to the base 1. The plate spring 8 needs sufficient elasticity to make the leg 10 or 5 it supports float up from a floor surface 15 or the base 1 against an empty weight of the chair 9. A sensor 14 is provided to detect a downward movement of the plate spring 8.
OSADA AKIO
NAGAI TOMIO
HOKURIKU MARUTAKA KK
TECHNO CRAFT KK