| 摘要 |
PURPOSE:To achieve the quality control for uneven thickness of a sheet material and higher yields thereof by arranging a ball made of a magnetic metal on one side of the surface of an object to be measured in the thickness while a magnetic core and a magnetic detector are arranged on the opposite side thereof to measure the online thickness of the running sheet. CONSTITUTION:A magnetic metal ball 7 is arranged on one side of the surface of a sheet material 2 as object to be measured in the thickness while a magnetic core 6, an AC power source 4, a magnetic detection coil 5 which detects changes in a magnetic field excited with a magnetic coil 3 and an electronic circuit 8 which amplifies and computes changes in the output voltage 14 of the coil 5. In this case, in place of the coil 5, one or a plurality of magnetic sensors 9 may be used. To achieve a fine contact with a thick body 2, a rotary space 12 is interposed between the magnetic core 6 and the sheet material 2. When measuring the sheet material 2, the metal ball is attracted by the magnetic core 6 to increase the adhesivity with the sheet material 2 through a freely rotary fine contact. As the thickness of the sheet material 2 varies, the magnetic field changes, causing a change in the output pressure of the coil 5. The output voltage 14 is amplified and computed with the circuit 8 to measure the thickness of the sheet material 2.
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