The Mechanical Handling and Storing of Material

5 3 THE MECHANICAL. HANDLING OF MATERIAL position by two supports in an oblique position, which give it greater rigidity. Such bearings are suitable for worms of large diameter. The construction '^almost explains itself, the halves of the bearing being connected by a staple which is U-shaped, and by the two distant pieces which are threaded on the shanks of the staple. Fig. 48. Solid Phosphor-Bronze Worm Bearing. Worm conveyors for fine cement and similar materials are frequently built on some- what different lines, and the tendency is to use more particularly the continuous or closed spiral. The principal differences are the use of a rather larger trough, for instance, an 11-in. trough for a 10-in. worm. This allows of a j-in. space between the movable worm and the stationary trough, so that the cement in the worm will form its own trough within the iron trough and that there is no wear at all on the trough itself. This arrangement, however, causes more wear on the periphery of the worm spiral, which thereby gradually becomes smaller in diameter.