THE WONDERS OF LIFTING MAGNETS.

Pelorus Guardian and Miners' Advocate., Volume 22, Issue 45, 13 June 1911, Page 2

THE WONDERS OF LIFTING MAGNETS.

WHAT A BOY’S TOY HAS BECOME.

Although the lifting magnet vis by no means new, during the last two or three years in particular its uses have multiplied to such an extent that many dew and widely different types have been designed to handle the multitudinous shapes of metal

produced. The magnet is iast becoming adopted to handle all forms of iron and steel from iron dust or scraps to weights of 20,000 pounds. In fact, the world’s largest magnet will lift as much as 50,000 pounds. Thus, Mr. W. Frank M’Clure points ' out in a paper the toy magnet of our boyhood is converted into a useful instrument in the workshop. Used at first chiefly in carrying iron and steel to and from cars or storage piles, the lifting- magnet is now utilised in breaking up imperfect castings, in holding of metal in position while being revited in the construction of ships, in lifting* a "sow and pigs” at the furnaces, also as a gigantic broom to sweep both the large and ' small pieces of iron, and in many other ways. A half-dozen kegs of nails may be seen travelling through the air, held by magnetic lines of force despite the wooden coverings of the kegs. Even two or three men are sometimes lifted from the ground, their feet resting upon a metal sheet, which is firmly held by the magnet. Lifting magnets are usually operated from an electric overhead travelling crane, but they may also be operated from a locomotive crane. Within the magnet are coils with which the service wires are connected just as an incandescent lamp is connected by service wires. The winding is, of course, insulated. When the magnets handle hot material, they are wound with fireproof wire. The movements of the magnet are directed by the operator of the crane. The opening or closing of a switch, turning the electricity on or off, causes the magnet to pick up or release its load. /

The 20,000-pound weight referred to as a typical large lift made by magnet power is in the form of a “skull cracker ball," used to break up imperfect metal that is to be remolted. The magnet used for th\g lift is 52 inches in diameter, and its weight 4,800 pounds. ,It requires 4 feet 6 inches head-room. When this great weight has been lifted high in the air, and the current is turned off, and the “skull cracker ball’' has fallen, the magnet again picks it up easily and quickly without any assistance from any one on the ground.

As a rule, a man on the ground is not necessary where a flitting' magnet is employed, for the reason that there, are no. chains,' slings, or hoisting blocks to b'e fitted about the weight to be lifted. However, there are a few instances where a ground man facilitates the work of the magnet. One of these is the lifting of an ingot, say, of 6,000 pounds. ,If a ground man places the magnet, two of these ingots can be lifted ; otherwise only one at a time. For if two ingots are to be lifted simultaneously, they must be in proper position, on account of their weight, for the magnet to grip them in their right place. Instead of the round magnet just described, a rectangular magnet is used in lifting a “sow and pigs” at the furnaces. When thus lifted from the sand they are- not white hot, but yet strongly heated. Hot metal in the form of billets is also lifted by a special magnet to a conveyer, and taken to where it is sheared or, cut into shorter lengths or to where it may be stamped out by a hydraulic press into car wheels and finished upon a lathe. A rectangular type of magnet is also used for holding steel plates in place to be riveted in the construction of ships. For two or three years past a number of these magnets have been in use at the imperial shipyards in Yokohama, Japan. Another interesting sight is afforded in the lifting of a very long metal sheet by one magnet applied at the sheet’s centre. The ends of the sheet may dip down to an angle of 45 deg. and still the sheet be-held tightly by the magnet. The use of the lifting magnet makes it possible to pile scrap iron in storage piles of unusual height with ease. It is not uncommon to see storage piles of this kind 25 feet high, and the work of piling it is done with great'rapidity. In, loading from waggons to storage piles, ithe work of hours when done by hand is reduced, to a few minutes by the use of the magnet.

With the 52-inch magnet, 600 to 800 tons of scrap are easily handled in a day of twenty-four hours at an openhearth furnace, even when four hours are allowed for delays. When thus operated day and night, the magnet takes the place of fourteen labourers. If operated with a specially fast crane, the amount handled is still further increased. The magnet mentioned as the most powerful in the world is 60 inches in diameter . and will handle “skull cracker balls” weighing 30,000 to 50,000 pounds. Siftings.”