GB948806A - Improvements in screening apparatus - Google Patents

Abstract

948,806. Sifting apparatus. ROSS ENGINEERS Ltd., and A. F. JONES. May 10, 1962 [June 15, 1961], No. 21607/61 Heading B2H. Screening apparatus of the kind having first and second spaced parallel screening rolls a, d respectively rotated in the same direction, the material to be screened being fed over the first roll a, which is smooth, i.e. in circumferential profile, and being carried by rotation of the rolls towards and over the second roll d, which is roughened or longitudinally ribbed. The roll d is driven in fixed bearings from a motor worm gear set f. The roll a is mounted for adjustment in bearings in arms c pivoted on a shaft b, one of the arms c being extended to provide a lever arm c<SP>1</SP> through which the pivoting of the roll a can be controlled by turning a handwheel e<SP>1</SP> secured to a screwed rod in a control apparatus e, which is as described in Specification 678,801. In the event of material jamming between the rolls, the roll a can move against the action of its own weight and against the action of a control spring or other resilient member in the control apparatus e away from the roll d to clear the jam. A sprocket on the shaft of the roll d drives a sprocket on the shaft b by a chain, and a further sprocket on this shaft drives the roll a through a further chain, so that the roll a can be moved without affecting its driving mechanism, Fig. 3 (not shown). Specification 376,273 also is referred to.