The Mechanical Handling and Storing of Material

SPEED-EQUALISING GEARS 193 adopted without making the terminals unduly large in diameter, thus reducing the number of wearing parts, and in consequence securing economy in first cost, is illustrated in Fig. 260. The countershaft a is driven by belt or gearing, at a constant speed; a second countershaft b is geared to the ter- minal spindle c in the ratio of 1 to 6, so that b completes one re- volution every time a point of the hexa- gonal terminal is uppermost. The two spindles a and b are geared together by wheels of equal dia- meter, which are bored sufficiently out of centre to make the d, the distance from centre to centre of the countershafts a and B, remains constant. The Link-Belt Gear.— Another equalising gear is that of the Link Belt Company, which consists of a wheel and one pinion only. The former has a waved or undulating circumference, and fits an eccentric pinion, the number of elevations and depressions of the spur wheel equalling the number of teeth in the conveyor wheel. The pulsating motion of these gears exactly counteracts the variations of chain speed, and eliminates the destructive strain set up by the constant accelerations and retardations that would result from the use of circular gears. The Barling Gear.—The principle of this invention con- sists in varying the angular velocity of the driving tumbler by the intervention of an epicyclic train operated by a cam, and is shown diagrammatically in Fig. 261. The shaft A is coupled direct to the motor and thus turns at uniform angular velocity ; it carries the wheel a which through the idle wheel b gears with the wheel c. The wheel b rides loose 13