The Mechanical Handling and Storing of Material

VIBRATING OR RECIPROCATING TROUGH CONVEYORS 121 if the links c are 14 in. long, the stroke 8, and the speed 51 revolutions, the actual stroke of the trough is 9 in., and the average speed of conveying 62 ft. per minute. He also found that the material followed the backward stroke of the trough for 3 to 4 in. The Marcus Conveyor.—This reciprocating conveyor consists of an open trough, the movements of which are essentially backward and forward in the same plane, unlike the Zimmer and Norton conveyors, which have, in addition to a similar movement, a swinging up-and-down motion determined by the arc de- scribed by the inclined supports. As this latter motion, which is the principal cause of the forward move- ment of the material in these con- veyors, is absent in the Marcus conveyor, some other means had to be found to give the propelling action. This has been provided by an ingenious crank drive with a drag-link, which gives the trough and its load a slow forward niove- Fig. 167. Perspective View of Torpedo Conveyor. ment and a quick return, so that the inertia of the material in the trough overcomes the friction offered by the trough and slides along whilst the trough returns. The forward movement of the material is said to be four-fifths of this stioke with each revolution of the crank. The trough is supported on rollers and channel stools, and the roller paths are fitted with renewable wearing flats, the rollers being kept in posi- tion by steel spindles and spiral springs. The speed at which these conveyors run is from 60 to 90 revs, per minute.