| 摘要 |
A method and apparatus for making asphalt shingles and particularly for applying varying overlay patterns of granular material to a web of roofing material to produce shingles of randomly varied appearance when the web is cut into shingles. Pattern variation is achieved by several techniques, including the use of irregular overlay imprint shapes and spacings, the staggered omission of one or more overlay imprints from the web shingle lanes, and the random omission of one or more granule drops during coverage of each pattern to change a randomly selected imprint from a predetermined granule color to the backfall mixture shade. The apparatus includes provisions for automatically changing the granule flow rate to accommodate speed changes. Provision is further made for resiliently supporting the web to prevent web damage during the cyclical granule drop.
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