Chain tensioning mechanism for scraper elevator device

In combination with a self-loading scraper having a tractor connected by a pull yoke to a trailing scraper bowl, said scraper bowl having an open end defined by a pair of laterally spaced side walls and a transverse cutting blade extending between the side walls, an elevator device located between and carried by the side walls of said scraper bowl, said elevator device comprising a frame, a drive sprocket wheel rotatably supported at the upper end of said frame, an idler sprocket wheel rotatably supported at the lower end of said frame, an endless chain having a plurality of transverse flight members connected thereto and being entrained about said drive sprocket wheel and idler sprocket wheel, a mechanism carried by said frame for tensioning said chain and having a pair of guide rollers engaging said endless chain, said mechanism being located midway between said drive sprocket and idler sprocket wheel and including a pair of arms pivotally interconnected in a scissors fashion, each of said arms having an inner end adjacent said frame and an outer end adjacent said chain, said pair of guide rollers being rotatably supported by the outer ends of said pair of arms so as to position the centers of said pair of guide rollers along a line that is substantially parallel to a line passing through the centers of said drive sprocket wheel and idler sprocket wheel, means pivotally connecting the inner end of one of said pair of arms to said frame, a guideway supporting the inner end of the other of said pair of arms on said frame for sliding movement along an axis parallel to the longitudinal axis of said frame, and a manually adjustable link in the form of a threaded rod extending between and interconnecting the outer ends of said arms for moving said guide rollers towards each other so as to increase the tension of said chain.