| 摘要 |
<p>The apparatus comprises: - a can (12) with a vertical axis, in the form of an upturned cylindrical pot, able to stand on a sheet of material (10) by means of the lower rim of its cylindrical wall (16), - a heavy body (20) of cylindrical form mounted so as to be able to slide coaxially inside the can between a raised position in which its upper surface butts against the can and in which its lower surface is exactly in the same plane as said lower rim (18) of the can, and a lowered position in which it rests with its full weight on said sheet and compresses it without piercing it, - and a comparator (54) able to measure the distance travelled by the heavy body due to its compressing of the sheet of material from its raised position defined above, when the checking apparatus is placed upon the sheet. <IMAGE></p> |
