GB510434A - Improvements in and relating to vibratory screens, sieves and riddles - Google Patents

Abstract

510,434. Sifting-apparatus. WATT, J. Nov. 15, 1938, No. 31420/37. [Class 117] The screening surface 1, Fig. 1, is in the form of a multi-sided, inverted truncated pyramid, and is actuated by a unit 2 comprising two out of balance rotors 23, 25, Fig. 4, rotating about a vertical axis at different speeds in opposite directions. In the construction shown, the rotor 23 is driven by a motor 22, and communicates its movement to the rotor 25 through gearing 24, 26, 27, 28. A vertical reciprocating movement may be imposed on the main movement by two out-of-balance rotors 31, 32 driven by the gears 27, 29 in opposite directions at the same speed about a horizontal axis 30 and synchronising at the vertically opposite points of their movements. The unit 2 carries the screen and is supported by rods 8 and springs 9 from a support 5 to which a rotary movement is imparted from a pulley-driven shaft 6 and gearing 7 so as to distribute the feed from a stationary hopper 10 around the periphery of the screen. Alternatively, the rotary movement of the screen may be dispensed with, and the hopper mounted to rotate. In another form, the unbalanced rotors may be replaced by eccentric driving mechanisms.