The Mechanical Handling and Storing of Material

184 THE MECHANICAL HANDLING OF MATERIAL length of the conveyor, each roll being geared to this shaft by a pair of bevel wheels with a ratio of about 3 to 1. I he rollers projected slightly through the bottom of the trough, in which the boards not less than conveyors are and effective, travelled at the rate of 150 to 200 ft. per minute, the rolls themselves making 60 to 80 revs, per minute. The boards to be con- veyed must be more than 10 ft. long, so as always to rest on two rollers. These very simple the most remarkable feature being that their construc- tion admits of their nego- tiating curves. (The one at the Millwall Docks de- scribed several curves having radii of 170 to 190 ft.) The steel driving shaft is sprung into these curves and appears to work well, though no doubt it consumes more driving power than the straight lengths. The conveyors have a separate electro- motor of 5 H.P. for every 500 ft. of their length, the motor itself half way. lengths of speeded to timber at 180 and 200 ft. per minute respectively. These conveyors will de- liver about 200 stan- dards 1 of 5-in. by 7-in. “battens” in ten hourSj and other sizes in pro- portion. Fig. 247 shows a Bolinder conveyor was length of the conveyor being placed Successive 500 ft. are convey the general plan of that portion of the Millwall Docks where the at work. 1 he line indicated 'by arrows illustrates the whole with its curves. 1 One standard of wood is 120 pieces 12 in. long by 11 in. wide and ip. thick, or its equivalent, t.e., 165 cub. ft. of timber. 3’3 standards make up one load.