PURPOSE: To obtain the compact and light weight displacement gate, by providing an optical means wherein a light reflecting body, light emitting and receiving elements, and the like are used, and detecting the displacement.
CONSTITUTION: A light emitting diode 1 and phototransistors 2 and 3 are arranged on the same straight line so as to face the light reflecting body 4. The change of a float 8 is transmitted to a cam 10 by a linking rod 9. The cam 10 is rotated by Δθ by the displacements Δh of a liquid surface, and the light reflecting body 4 is moved by Δl. When said reflecting body 4 is moved by Δl, the rate of change in the output of the phototransistor 2 reflecting body 4 is different from the rate of change in the output of the phototransistor 3 with respect to the displacement Δl of the light deflecting body 4. Therefore, by obtaining the output ratio, the distance to the light reflecting body 4 can be found. In this way, since almost negligible number of mechanical elements is used in the constitution of the detectors, the device can be made compart and light weight.
NAGAO HISAO
KUWAMURA KOUICHI
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