THE WONDERS OF LIFTING MAGNETS.

Thames Star, Volume XLVII, Issue 14660, 28 October 1913, Page 3

THE WONDERS OF LIFTING MAGNETS.

WHAT A BOY'S TOY HAS BECOME. Although the lifting magnet «s by no means new, during the last two or three years it particular its usea bave multiplied to such an extent that many new and widely different types have been designed to handle I the multitudinous shapes of metal i produced.' The magnet is fast 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 sheets oi metal in position while being revitecl 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 forco despitr the wooden coverings of the kegs. I"7en two or' three men are someti.nes 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 con- . nected by service wires. , The. winding 1 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, j, causes the,,magnet to pick up or release its load. The 20,000-pound weight referred tc . as a typical large lift made by mag- £ , net power is in. the form of a "skull £ .cracker ball," used, to break up im- £ perfect,metal that is to be remelted. The, magnet, used for this lift is 55 • inches in diameter, and its. weight 1,800 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 "skuir cracker ball" has fal-' ►" .len, the magnet again, picks it vi y ' easily and' quickly without any as- ►■' sistance from any one on the ground As a rule, a man on the ground it ►■- not necessary where a lifting magnet ►■ Is employed, for the reason that! ►• there are no chains, slings, or hoist- ► ing blocks to be fitted about the X weight to be lifted. However ', , there ►» are a few instances where a ground ►■ man facilitates I'the work of the mag- ►■■ 'net. One of these is the lifting oi an ingot, say, of, 6,000. pounds. 4 If a ►■- ground man places the magnet,, two ►-; of these ingots can be lifted ; othery. ; wise pnly one alia' time; • For i,f two y. - ingots are,,to be lifted simultaneousy ly, they must be in,proper,position, on. account of their weighjt, for,the ! magnet to grip them in their. right place, j Instead of the round magnet just lescribed, a rectangular, magnet is 1 ised in lifting a "sow and pigs" at the furnaces. When thus lifted 1 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 hydrau- " lie 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 (J ,For. >■ two or three years past a number of ; h these magnets have- been in use. at k 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 y the magnet.' ► ' The use of the lifting magnet makes it possible to pile scrap iron in storage piles of unusual,height with ease. 25 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, the 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. — " Popular Science Sittings."