The Mechanical Handling and Storing of Material

CONTINUOUS HANDLING OF MATERIAL ELEVATORS, CONVEYORS, AND A COMBINATION OF THE TWO APPLIANCES ELEVATORS A. FOR MATERIAL IN BULK; B. FOR LARGE OBJECTS CHAPTER II A.—ELEVATORS FOR MATERIAL IN BULK Introductory.—The most ancient method of elevating material, although it cannot strictly be called an elevator, is none the less of interest; as all the members composing such a machine are present without, however, the mechanical element, it may be termed a human elevator. Fig. 21 is a reproduction of a part of an alabaster bas-relief dis- covered by Sir Henry Layard. It formed part of the wall decorations of the palace of Sennacherib, the Assyrian king who destroyed Babylon in 694 b.c. The illustration is one of a series representing the building of the palace. The men are captives from the city of Balada, and are raising an artificial mound or platform upon which the palace was erected. The alabaster slab is now in the British Museum. Elevators in a primitive form have been known and used for a very considerable time, and since their introduction have undergone little alteration except in detail. 1 he term elevator is usually applied to endless belts or chains to which are attached a series of suitably shaped receptacles or buckets. These chains or belts run over two terminal pulleys which are fixed at different levels, the distance from centre to centre of these pulleys being called the length of the elevator. It is not intended to waste space here by going into details of the construction of the numerous types and patterns of chains and buckets used for elevators, and which are made by specialists with special plant, beyond giving the actual shape of the buckets, as it is obvious that a light chain and buckets of a thin gauge will answer for light materials, whilst heavy chains and buckets should be used for specifically heavy, and especially cutting materials. Elevators are designed to suit special purposes. For instance, grain elevators are always encased in wooden or iron trunks, the head and foot being also of wood or iron. The position of the elevator trunk in this case is nearly always vertical. The support for the buckets consists either of leather belting, cotton belting, hemp webbing, or india-rubber with insertion. For minerals—coal, coke, cement clinker, and other heavy 1 From “ Engineering of Antiquity,” by G. F. Zimmer. IO