| 摘要 |
<p>Device for producing arrays of fine scratches on the surfaces of certain materials, esp., plastics, device comprises a rigid golder for a pair of replaceable toothed blades having a large number of fine teeth mounted so that the blade projects from the holder by only the depth of the teeth. Esp., for scratching the surfaces of e.g. blanks for plastic carrier bags. The holder may be drawn over the surface or operated as a pendulum skimming a base plate with curved toothed strips.</p> |
