Patent ID: 6098811
Filing Date: 2000-08-08
Classification: B07B

Abstract:
A method for screening an unsorted mixture of discrete objects to separate said objects by general size, comprising:providing a grizzly screen with generally parallel primary and secondary grizzly bars all having first and second ends, said bars pivotally attached at a first end to a transverse end member, said grizzly screen pivotable about an axis intermediate said first ends and said second ends and spacedly proximate said second end, said primary grizzly bars having a greater length than the secondary grizzly bars;applying loads of the unsorted mixture of objects onto said grizzly screen to be separated by and discharged from said screen;stopping the application of said mixture to said screen when oversize objects become retained between the grizzly bars;raising said transverse end member to elevate said first ends of said grizzly bars and differentially lower said secondary grizzly bar relative to said primary grizzly bar to increase interbar spacing, whereby said retained oversize objects are discharged to clear said screen.