GB297706A - Improvements in and relating to grizzlies and screens for grading materials - Google Patents

Abstract

297,706. Ross, W. June 25, 1927. Rotary sieves; endless moving sieves.-In screens of the kind described in Specifications 123,201 and 179,562, comprising two sets of bars which lie at a predetermined distance apart and in the same plane in the screening zone and are moved apart in different planes outside that zone to facilitate discharge of the fines, the bars are mounted in their carrier members, such as chains or discs, so as to have freedom of movement relative thereto for the purpose of providing a sudden and appreciable enlargement of the screening space as the bars near the oversize discharge point. Figs. 3 and 4 show one application to the drop bar type of screen described in Specification 123,201. The main bars b have a bearing in an elongated hole a in the chain, and the link c carrying the drop bar d has an elongated hole e in which is freely socketed an extension f<1> of a chain link. The drop bar is held in the screening zone by the engagement of a lug g<1> on the link c with a bolt. head g on the chain. Alternatively, the bars may have tubes of greater bore mounted loose on them, or they may have eccentric trunnion ends