In addition, it reduces the strain on screen frames and pans - lets you operate with less maintenance and fewer changes of prematurely worn screen plate or mesh. The heavy bottom spring carries the weight of the screen and its downgoing thrust, while the smaller top spring absorbs the upgoing thrust. Built extra heavy to give rigid support for the bearings and screen pan, the Mesabi's main frame will carry both the screen and its heavy load of materials without a sign of sag or twist. The basic frame consists of heavy channels reinforced with wide-flange cross beams. The heavy vertical bracing under the housing also helps maintain the shaft in proper alignment and prevents sagging.
Centrifugal force holds the counterweights on the shaft without strain on the bolts.
Bottom sizing deck support frames are built of angles, bars, pipes and beams. Discharge spouts, receiving hoppers and washing and spraying equipment can be added as desired. Pan rides on inner bearings of the eccentric shaft which imparts fully positive, circle-throw vibratory action. Corner spring supports maintain pan in proper screening position. Bolted-in liners protect the pan sides.