GB550661A - Improvements in or relating to sifting apparatus - Google Patents

Abstract

550,661. Shifting apparatus. HURST, J. July 15, 1941, No. 8952. [Class 117] [Also in Group XXV] Gyrating sifting apparatus comprises one or a number of superposed sieve units 19, 20, each comprising a circular sieve 23, stretched over a frame 22 and surrounded by an annular collecting trough 31. The sieve is folded over the frame 22 and is secured by an encircling band 24 and bolts 26. Preferably a collecting tray 127 is formed with the frame, and discharges the fine material passing the sieve by way of a central opening 43 and duct 46 to the outside of the apparatus. The annular collecting trough is formed by a conical tray 29 with an upstanding edge 30 which is secured in spaced relation to the tray 127 by brackets 27, and is secured, as by spot welding, to a circular outer casing 32. A threaded bolt 48 with a pointed end for piercing the sieve, nuts 49, 51, 52 and washers 50 secure the parts together centrally and are preferably adjusted to impart a slightly conical shape to the sieve. The upper edge of each casing is offset at 33 to hold a rubber gasket 34, on which the lower edge of the one above rests, or in the case of the uppermost one the edge of a lid 35 provided with a central feed spout 36. The assembled sieves are clamped in a frame between a transverse support and cross-bars lying across the lid. The fastening means may be bolts or the quick release device shown in Fig. 2. This consists of a rod 63 engaging a slotted lug 61 on the bottom support 14 and acted on by a spring 64 bearing against the under side of the lug. The upper end of the rod has a loop 71, engaging a toggle lever 67 pivoted at 69 to the bar 65 lying across the lid. The supporting frame is slung from a hook and carries a motor driving an out-ofbalance weight by which the movements are derived. A hopper with a regulating slide is connected by a duct to the central feeding aperture in the lid.