Document Type and Number:
Japanese Patent JPH0523684
Kind Code:
B2
Abstract:
PURPOSE:To achieve an accurate measurement of the thickness of a sheet, by measuring and computing a distance to a non-metal sheet and the surface thereof with a first distance sensor and a distance to the sheet and the surface of a mount with a second sensor having the surface thereof justified with the sheet carrying it when the thickness is measured concerning a non-metal sheet carried on a metal-made sheet mount. CONSTITUTION:A non-metal sheet 2 intended to measure the thickness thereof is carried on a metal-made mount 3 and an eddy current sensor 42, an amplifier 64, a differential air-electricity converter 47 and an amplifier 65 within a measur ing section 4 are turned ON to run air to obtain an output signal V correspond ing to a distance H between the sensor 42 and the surface of the mount 3 and an output signal X corresponding to a distance H between an air sensor 41 and the surface of the sheet 2. Then a comparator 61 determines a difference between the signals X and V. Here, as a reference measuring surface of the sensor 42 is justified with the undersurface of the sensor 41, an output signal of the comparator 61 corresponds to the thickness of the sheet 2. This can cancel effect of irregularities of the surface of a conveying roller as the mount 3, thereby assuring accurate measurement of the thickness of the sheet 2.
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Inventors:
FUJIWARA HIROSHI
Application Number:
JP16186287A
Publication Date:
April 05, 1993
Filing Date:
June 29, 1987
Export Citation:
Assignee:
SEKISUI PLASTICS
International Classes:
G01B21/08; G01B7/06; G01B13/06
Next Patent: JPH0523685