| 摘要 |
<p>A hard plate such as blank paper board can be held under suction on a table, such as the table of a coordinate plotter, with air holes bored therethrough, by superposing a soft sheet, which includes an air-permeable portion at a desired location and an air-impermeable portion made of an air-impermeable elastic material and surrounding the periphery of the air-permeable portion, over the table in such a way that the air-permeable portion is communicated with the air holes; superposing the hard plate on the soft sheet in such a way that at least the air-permeable portion is covered by the hard plate; and sucking air through the air holes to hold the hard plate by vacuum. Use of the soft sheet permits easy, prompt and sure positioning of the hard plate even if a warp or distortion is contained in the hard plate.</p> |
