Below is a list of Grizzly Screens manufacturers from Quakertown, Pennsylvania. A grizzly screen, also referred to as a grizzly scalper or a grizzly feeder, is an extremely rugged type of low horsepower vibrating screen that is placed between a vibrating feeder and a primary crusher. Most often used for pre-screening, the typical feed materials that require grizzly screens versus the typical vibrating screen are very coarse aggregates.