The Mechanical Handling and Storing of Material

WORM OR ARCHIMEDEAN SCREW CONVEYORS 43 Fig. 41 shows such a conveyor, but both this and the wooden type are quite antiquated now. More modern constructions used at the present day are illustrated in Figs. 42 and 43. They were probably introduced at the beginning of the nineteenth century. Fig. 41. Worm Conveyor composed of Cast-Iron Blades and fitted with Square Spindle. Fig 42 represents a so-called paddle worm constructed of a series of blades forming together as nearly as possible a complete screw. Each of the blades is fixed to a central shaft or spindle by means of its shank, which is tapped and fitted with a nut. The Fig. 4'2. Paddle Worm, or Broken-bladed Conveyor. spindle is made of steam pipe in lengths of about 8 ft., the different lengths being coupled together by turned gudgeons, which answer at the same tune as journals tor the bearings. Fig. 43. Worm with Crescent Blades. Another type of conveyor akin to the broken-bladed worm is that known as the crescent-bladed worm, Fig. 43. Each paddle is extended in the form of a crescent so that it forms practically a semicircle held out from the spindle by the shank. Two crescents form one complete spiral, and thus only two blades are required instead of