GENERAL NEWS

Thames Star, Volume XLVII, Issue 14492, 4 April 1913, Page 8

GENERAL NEWS

THE WONDERS OF LiFTIftG WAGi-iEVS. WHAT A BOY'S TOY HAS BECOME.

Although the lifting magnet is by no means new, during the last two ot three years in particular its use 3 have multiplied to such an extent that many new and widely different types have been designed to handle the multitudinous shapes of metal produced. The magnet is last 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 ma : net will lift as much as 50,000 pounds. Thus, Mr. W. Prank M'Clure point: out in a paper the toy magnet o! our boyhood is converted into a useful instrument in the workshop. Used at first chiefly in carry in£ iron and steel to and from cars or storage piles, the lifting magnet is now utilised in breaking up imperfect castings, in holding sheets ol metal in position -while being revited in the construction of ships, in lifting a "sow and pig*" at the furnaces, also as a gigantic broom to sweep both the large and small pieces ol 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 th; wooden coverings of the kegs. Even two or three men are sometimes lifted from the ground, their feet resting upon a metal sheet, which i£ 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 crana. Within the magnet aye coils with which the service wires are connected just as an incandescent, lamp is connected by servica "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 ralease its load. The 20,000-pound weight, referred tc as a typical large lift made by magnet power is in the form of a "skill! cracker ball," used to break up imperfect metal that is to be remelted. The magnet ussd 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 "skull cracker ball" has fallen, the magnet again picks it vi 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 lifting magnet Is employed, for the reason that there are no chains, slings, or hoisting blocks to be fitted about the weight to be lifted. However, then are a few instances where a ground man facilitates the work of the magnet. One of these is the lifting ol nn ingot, say, of 6,ooo"pounds. If a ground man places the magnet, two of these ingots can be lifted ; otherwise only ono at a time. For if t,vc ingots are to be lifted simultaneously, they muse be in proper position, on account «f their weight, for the magnet to grip them in thair right place. Instead of the round magnet just lescribed, a rectangular magnet is ised 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 ol 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, 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, GOO 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 iv the world is 60 inches in diameter . and will handle "skull cracker balls" weighing 30,000 to 50,000 pounds. — " Popular Science Siftings."