GB1035711A - Improvements relating to vibratory sieves and conveyors - Google Patents

Abstract

1,035,711. Screening apparatus. A. WEHNER. Jan. 3, 1964 [Jan. 5, 1963], No. 429/64. Heading B8A. [Also in Division B2] A vibratory screen 10 is carried in operation by primary and secondary sets of support members 3, 4 alternately, the primary set performing a circular motion and being coupled to the screen in a manner such as to impart both the upper part of the vertical component of its motion and the whole of the horizontal component of its motion, and the secondary set being mounted to move in such a manner that there is substantially no relative sliding between itself and the screen. As shown, the screen 10 is oscillated in the direction indicated by the arcuate arrow by cross-bar support members 3, 4 secured respectively to primary and secondary frames 1, 2 which are supported through springs 7, 8 on a main frame G and driven by oppositelyrotated eccentric drive shafts 5, 6 passing through the c.g. of each frame. The cross-bars 3 are provided with driving pins 13 which provide the horizontal component of movement of the screen and permit the screen to lift against the action of springs 14 when under the influence of the cross-bars 4. The arcuate movement may be inclined by using a different eccentric setting, Fig. 3 (not shown). If desired, the passage of material over the screen may be assisted by tilting the screen downwardly. In another embodiment, Figs. 4 to 6 (not shown), the screen is given a semi-circular movement as indicated by the arrows. In this arrangement, the frame 1, which carries cross-bars 3, is driven by an eccentric or out-of-balance drive 5<SP>11</SP> and the frame 2 is arranged to rest on springs 8 so that a horizontal return movement can be imparted to the frame 2 from the screen when the latter settles on the cross-bars 4. In operation, the frequency of oscillation of the frame 1 is arranged to equal the natural frequency of oscillation of the frame 2 to avoid sliding friction. In another embodiment, Figs. 8 and 9 (not shown), the frames 1 and 2 are linked together so as to give a crescent-shaped movement to the screen as indicated by the arrows. In this arrangement, the frame 1 is driven with a circular movement by an eccentric or out-ofbalance drive 511 and the frame 2, which rests on leaf-springs 16, is driven by a link 15 from the frame 1. In another embodiment, Fig. 10 (not shown), for the production of arcuate movement of the screen 10, the eccentrics 11<SP>1</SP>, 12<SP>1</SP> rotate in the same direction. The pins 13, 13<SP>1</SP> are axiallyslideable through the screen, the pins 13 being rigidly mounted on the cross-bars 3 to transmit horizontal movement while the pins 13<SP>1</SP> are connected to the cross-bars 4 by flexible supports 21 made of rubber; this kind of drive is suitable for the supply of electricity to heat the screen. The screen may form the bottom of a bunker containing loose-fill material and in a multi-deck arrangement, such as in Fig. 7 (not shown), the additional screen or screens may perform the same or different forms of oscillation. If desired, the cross-bars themselves may form part of the screen.