Apparatus for scraping debris from a trash rack occupying a position in a owing stream has a driven, upper turning drum and a pair of chains trained about the drum and carrying scraper blades which engage and carry debris on the upstream side of the rack upwardly for disposal. Each chain is composed of a plurality of links joined at their ends by pivot connections which limit the pivotal movement of the links from positions of linear prolongation in such manner as to avoid the necessity of a lower turning drum. By supporting the chain from an upper drum only, the lower parts of the chain are movable freely in directions away from and toward the rack, as well as vertically.