Grizzly and screen for grading materials

摘要

555,350. Screening apparatus. ROSS, W. March 17, 1942, No. 3530. [Class 1171 In screens of the kind comprising travelling bars extending transversely of their direction of travel, the outer ends of the bars are recessed to engage the upper edge of a guide rail over which they travel so as to restrict lateral movement. The invention is described as applied to screens of the kind described in Specifications 123,201, 179,562 and 297,706, [all in Class 117]. comprising main bars 1 supported by a chain 3, and drop bars 2 supported by links 2c so that in the screen zone during the upper run of the screen the bars are supported by the rail 9, while in the lower run, the bars 2 drop and enlarge the screening openings. The recesses 10, 11 in the bars are of flattened V-shape and engage the bevelled upper edge of the bar 9. Alternatively the recesses end the guide bar may have square sides, in which case a slight play is allowed. To enable the chain 3. to accommodate slight movements, the connecting links 4 are tapered to provide a clearance D, and some play is also allowed at the bearing surfaces 7, 8 and E. Hanging chains may be provided at the delivery end of the screen to minimize irregular discharge, and a baffle may be provided across the screen near its feed end to regulate the distribution of the load. The guide rail is preferably supported on springs.