GB1084827A - Improvements relating to machines for grading beans and the like - Google Patents

Abstract

1,084,827. Screening apparatus. CHISHOLM-RYDER CO. Inc. March 1, 1966, No. 8838/66. Heading B2H. A screen-drum for grading beans comprises a plurality of bars 21, 21 and articulated leaves 25, the latter being movable by means 29 for adjusting the grading clearance. The bars 21, 21' are supported in end plates 5 which are mounted on rollers 7 for rotation through a gear-ring 11. The leaves are hinged about an axis 23 and operated by toggle links. To decrease the clearance, the links are urged upwardly against the action of a spring 37 by a wedge-shaped member. 45 on a bar 43 when the latter is moved axially by a member 55. The member 55 is mounted by pins 63 in helical slots 65 of a support ring; to adjust the clearance, the ring is rotated by means of a handle 67, the clearance being indicated on a scale 80. Each bar 43 is urged by a spring 49 against a cam-surface 57 on the member 55 so that during rotation of the drum, the clearance is increased in the upper half of the drum to release beans which have become jammed. In another embodiment, Figs. 10-18 (not shown), the leaves are formed by resilient U- shaped members and are actuated by diamondshaped members (91) mounted on rotatable bars (93), each bar being mounted on a crank and roller assembly (95) which rides on an inclined surface of a ring (105); to adjust the clearance, the ring is moved axially against the action of at least one spring (115) by a handwheel (117). The ring is divided into two halves giving two different cam surfaces (103'), (103") to produce a larger clearance when rollers (101) of the crank and roller assembly ride on the upper half of the ring.