GB182962A - Improvements in or relating to screening or sifting apparatus - Google Patents

Abstract

182,962. Horsman, W. E., and May, W. H. April 25, 1921. Reciprocating sieves. - Sifting-apparatus for screening coal, granular and like material and adapted to be reciprocated by hand or power comprises a jointed link suspension for the screen structure, cams carried thereby and a series of spring-controlled pivoted arms co-operating with the cams to give a jigging motion to the screens. The cams are provided with inclined surfaces terminating abruptly and the co-operating arms are provided with stops which allow movement in one direction only when engaged by the abrupt faces of the cams. The screens 4 and a discharge shoot 5 form an integral structure which is suspended by jointed links 7 to allow vertical movement, and is reciprocated by a connecting-rod 10 operated from a shaft 9. To the bottom of the structure are attached cams 14 which slide over rollers 18 attached to spring-controlled arms 17 which are pivoted on the fixed framing 1. When the screen structure moves in the direction of the arrow, Fig. 3, the cam 14 engages the roller 18 and raises the structure, the arm 17 being prevented from moving to the left by the abutment 17<1> engaging the framing. When the end of the cam passes over the roller, the screen receives a sudden jerk, the links 7 being of such a length that the screen structure does not fall on the rollers. On the reverse movement, the arm 17 moves about the pivot 19 and allows the cam to clear it, the spring 20 bringing it back to its original position. In a modification the levers 17 are pivoted to brackets secured on the frame 1. The cams may be carried by the machine framing and the pivoted arms by the screen structure. A hopper 22 for feeding the material to the sieves is provided.