The Mechanical Handling and Storing of Material

4i6 THE MECHANICAL HANDLING OF MATERIAL An up-to-date lifting magnet is no more likely to fail and drop its load than is a hoist cable or chain. One of the great economies in raising loads with lifting magnets, as compared with ordinary cranes, lies principally in the saving of the time wasted in slinging the material with chains prior to its being raised, and the removal of the chains at the destination. Another is that practically all ground men become unnecessary. The Hulett Unloader.1—To empty open barges some grabs, manipulated by cranes, can be used, which will discharge nearly the whole contents of the boat, rendering hand trimming practically unnecessary. In discharging larger vessels, however, which have narrow hatchways, like those in universal use on the great American lakes, the Fig. 588. Hulett Unloader as Used by the Pennsylvania Railroad Co. at Cleveland, U.S.A. ordinary grab can only attack the material which is directly beneath the hatchway, the rest having to be trimmed up to the point which the grab commands. To obviate this necessity for trimming, the American engineer, Mr G. H. Hulett, of the Wellman-Seaver-Morgan Co., Cleveland, Ohio, has successfully designed a discharging apparatus which can handle the material lying out of normal reach by drawing it towards the hatchway. The machines are built by the Wellman-Seaver-Morgan Co., and the first installation was made at the iron ore docks of the Pittsburg and Conneaut Dock Co., of Conneaut, Ohio, in 1898. In these unloaders the clamshell, which is of large capacity, was rotated after entering the hatch, so as to extend lengthwise of the boat, enabling it to reach the ore tributary to each hatch. The latest and most up-to-date installation of this type, as used on the banks of the great American lakes, is that of the Pennsylvania Railroad Co. at Cleveland, Ohio, which was completed in 1 The Author is indebted for the foregoing facts and figures, as well as the illustrations, to an article by A. Bergman, of Stockholm, which appeared in Zeitschrift des Vereins deutscher Ingenieure of 28th February 1914.