Engineering Wonders of the World
Volume III

REMARKABLE MACHINERY. 271 ways, and bearing a trolley fitted with a hanging portion built up of steel plates and Slab Chargers. angles. Within this hanging portion slides a steel frame- work, to the rear portion of which is attached the operator’s cab, and in front is a massive cast- steel bar fitted with a suitable grip for holding the slab. The framework is raised or lowered by suitable gearing upon the trolley. It is also made to turn about a vertical axis, and travel both down and across the shop. The operator is thus enabled to pick up or set down a slab over a large range without any outside help whatever. The method of holding the slab varies with the conditions of working. Sometimes the machine is arranged to grip the ingot by the sides, and sometimes by the ends. Then there is what is termed an “ alligator ” grip, which seizes the slab as be- tween the thumb and finger. A special feature about the grips is that they are so designed that the pressure required for holding is de- rived from the weight of the ingot itself, and any slackness through shrinkage of the ingot by cooling is automatically taken up. Ma- chines of this type handle quite easily slabs up to twelve tons in weight. It now only remains to cut up the finished product into the length required, and to load it into wagons for transport. For cutting up the plates, etc., a machine called a shears is used, furnished with two blades working on the same principle as those of a pair of scissors. These machines are of enormous power, and will shear a cold plate 10 feet wide and 1| inches thick at one stroke. They are operated by hydraulic power and fitted with steam inten- sifiers. Some of the large shears designed for shearing armour plates exert a pressure of 5,000 tons. In appearance they suggest a very massive hydraulic press having a fixed blade at the bottom and a moving blade attached to the hydraulic rams. The shears are, of course, fixed, and the material has to be brought to them, generally by overhead cranes. / For stocking the material in the yards and loading it into wagons there are special cranes, either of the Goliath or gantry type, covering a range of sometimes 150 feet. They are fitted with magnets for handling the material, are electrically driven at high speeds, and effect a great economy over the old jib cranes. The machinery described in this article does not by any means comprise the whole of that used in a steel works. In fact, not one-quarter has been mentioned—only those parts of the plant that are most interesting. If the reader wishes to go further into the subject, he should obtain permission to visit a large steel works, and see for himself to what a pitch of perfec- tion the rapid handling of hot and heavy material has been brought. [Note.—Thanks are due to Messrs. Wellman, Seaver, and Head, Ltd., for supplying many of the photographs illustrating this article.}