Patent ID: 7490381

Claim:
A tube scraper comprising an arbor defining a longitudinal axis, a set of scraper blade arms being mounted on the arbor defining adjacent blades spaced about the axis, the blade arms are movably mounted on the arbor for movement along the scraper axis, each blade arm having recessed side edges extending forwardly of the one end and terminating in a forwardly projecting scraper blade, each scraper blade having a concave curvature for insertion into a tube, each blade having spaced lateral blade tips with respect to which the blade arm side edges are recessed, each blade further having a front face with leading edge extending across the blade from lateral tip to lateral tip for scraping deposits from a tube interior wall, the set of blade arms being positioned on the arbor so that the leading edges of the lateral blade tips of adjacent blades overlap to provide an overlapping blade scrape pattern for scraping the entire circumference of a tube interior wall, the arbor and each blade arm are provided with cooperating ratcheting surfaces for driving the blade arms radially outward when the blade arms encounter a tube wall deposit, and a piston fitted to the arbor for propelling the scraper through a tube.