Sand Sifters
The common kinds of sand-sifters are made to operate by either hand or power, and usually consist of a stout oblong frame supported on four legs, inside of which the sieve or riddle is caused to move rapidly back and forth by a mechanical device attached to the end of the frame. Some makers claim six movements of the sieve to each revolution of the driving-wheel or pulley; the object in this being to prevent clogging by imparting a constant jarring motion to the sifter. Other sifters are suspended from beams above, and an oscillating motion imparted to them by a three-toothed cam-pinion, the teeth of which thrust (alternately); pins in the slotted piece attached to the bar which actuates the sifter, and a rapid back-and-forth movement is imparted thereto. See RIDDLE.