The Mechanical Handling and Storing of Material

PICKING BELTS OR TABLES i°3 screening is vitiated. It is on this account that in some cases the picking belt has been provided with a jib extension, of which it is the special function to load the coal into wagons. If a separate loading device is used, a second fall seems to be un- avoidable as the coal passes on and off the lowering device. Elevation and Plan of Wooden Slat Conveyor. The Koch belt is the nearest approach to a flexible steel band, and if it were a thoroughly practical appliance it would be an ideal picking belt. It consists of separate plates curved to form segments of the terminal drums (see also Fig. 127) carried upon double link chains and provided with rollers. The curvature given to the plates makes them very rigid transversely, but unfortunately the belt cannot be so made that the discharge shoot can be closely applied to the nearly cylindrical end. Hence, if placed high up to prevent any fall of the coal, the smaller particles will fall through the gap. The usual form of belt, composed of flat plates, attached to two or three link chains according to the width of the belt, has this drawback, that the delivery over the end can only be made by setting the receiving shoot well below the centre of the terminal drum, on account of the backward and forward motion on the end, according as the flats or the angles of the polygon drums are presented to the receiving shoot. To overcome this difficulty, Howe’s delivery shoot, Fig. 134, has been introduced, and has proved fairly efficient. The shoot a is so suspended as to have a tendency to lie close up to the belt terminus, and two upturned horns b at either side are kept in contact with the conveyor plates, and serve to make the shoot follow and conform to the motion of the plates. In the illustration, the shoot a is shown as a short screen to