The Mechanical Handling and Storing of Material

AUTOMATIC FEEDING DEVICES 205 material, allowing it to fall into the shoot. The plate is moved by a connecting rod from crank or'eccentric. The capacity is determined by the length and number of the strokes and the location of the gate. The disadvantages are the lack of adjustment and the inability to clear the feeder of material. The shaking feeder, Fig. 280, consists of the shaker-pan located under the opening in the bottom of the hopper at such an angle that the material will not flow when the pan is stationary. When given a re- ciprocating motion by the crank and connecting rod, the material is moved forward on the pan. The front end of the pan is carried by a pair of flanged wheels / the back end is suspended by two hanger-rods, each being provided with a turn-buckle so that the angle of the pan may be varied. The crank having an adjustable length of stroke, there may be three variables, viz., number of strokes, length of stroke, and inclination of the pan. As the number of strokes is difficult to change, and the others easily changed, the feeders are usually designed for about seventy-five strokes per minute, a number determined by experiment. The angle of the pan is fixed by the capacity desired and the nature of the material handled. For coal, stone, ore, etc., 8° to 10° is sufficient, while clay and other sticky substances require from 15° to 20°. The length of the stroke varies from 4 to 12 in., so that a large range is possible. A feeder designed to handle 400 tons per hour of mine-run coal was changed in five minutes to deliver 30 tons per hour by shortening the length of the stroke and lowering the pan until nearly horizontal. Not only has this feeder the widest possible range in capacity, but it is self-cleaning, a very important feature in countries where there is a severe winter. From the illustration it will be noted that the pan is placed under the opening, and the material rests directly on the pan, so that when the pan is moved the material in the hopper is moved, which prevents the material from bridging. The shaking feeder has none of the disadvantages of the other types for general use, and possesses many advantages which the others lack. Owing to its great flexibility it is