A device is disclosed for producing surface channels of at least approximately rectangular cross-section in sheeting consisting of a soft material, in particular mineral-fiber insulating mats or sheeting consisting of a styrene polymer. The device makes use of a motor-operated cutting tool with an oscillating...http://www.google.es/patents/US5231910?utm_source=gb-gplus-sharePatente US5231910 - Device for producing U-shaped surface channels in sheeting
Device for producing U-shaped surface channels in sheeting
