APPARATUS AND METHOD FOR THE PRODUCTION OF GROOVES OR RIBS IN OR ON A SURFACE

摘要

A mask (1) for the production of grooves or ribs in or on a surface is made of sheet material and has at least two rows (2, 3) of parallel sided apertures (4, 4a) therethrough. The apertures (4) of row (2) are in laterally spaced apart side by side relationship. The apertures (4a) of the second row (3) are also in laterally spaced side by side relationship but staggered relative to the apertures (4) to leave a reinforcing web (7) between adjoining first and second row apertures (4 and 4a).