The Mechanical Handling and Storing of Material

ELEVATORS FOR MATERIAL IN BULK 11 materials—elevators are usually fitted with sprocket wheels and chains which support the buckets. The elevator in the latter case is generally in a slanting position. The buckets are attached to the links of the chain, and intermediate short skidder bars are employed which slide on well-oiled angle-bars on each side. For extra heavy work Fig. 2. Human Elevator Constructing a Mound upon which the Palace of King Sennacherib was built. From a bas-relief of this palace, now at the British Museum. the skidder bars are replaced by rollers. These prevent the buckets and chain from sagging. Tightening Gears.—Both grain and mineral elevators are generally furnished with tightening gears to keep the belt or chain taut. These are generally arranged at the lower or well end of the elevator, because if placed at the top or delivery end the tightening of the chain or band disturbs-the driving arrangements, which should beat the upper terminal. The ordinary tightening gear at the elevator well has this dis- advantage, that the space between the bottom of the well and the bucket must vary.