Document By7yzogMn3z7dyga5G08O5kxw

it!. Thl- 450-tun Fairly cran.-s, des;..IK,i and U.ilt by The All.muv hs M -chine Company. Alliance, Ohm, , die luiir-eirder type, wnh the 'mn,, hoist trolley running on heavy outside girders, and the auN.l.ary Elliott mill-type mo tors on open-hearth ladle crane bridge and trolley drives. TO.--! This view oj one of the large Fairless c ranes shows the elaborate pre-story rah in whic h the operator rides. The main heist hooks are in the foreground: the ta ct smaller auxiliary hoists con he seen ninny and behind the main hoist. The hoisting mechanism of the crane includes a two-motor synchronized worm drive and a double-drum interlocked-type main hoist. The synchronizing shaft em ployed in the gearing scheme makes possible an addi tional safety factor in case one hoist motor fails. Under this condition, both worms are driven by the remaining motor. The hoist gearing is so proportioned that full crane capacity can be lifted by one motor without exceeding the quarter-hour rating. After the hooks, trolleys, girders, etc., had been de signed, the total weight of the crane was calculated to be some 1,100,000 pounds. With this as a basis, the maxi mum wheel loads, and the design of end trucks, wheels, and runway rails were determined. The largest runway rail used for these cranes weighs 175 pounds per yard and the largest rolled steel wheel is 30 in. in diameter. This combination will allow a maximum load per wheel of 123,000 pounds. Six 30-in. diameter wheels were re quired on each corner, or a total of 24 wheels. In order to obtain good traction, two wheels out of each group of six are driven. As important as the mechanical design of the Fairless ladle cranes are the steps taken for the safety and pro tection of the crane operator. He is normally located on the lower floor of a five-story cab which has heatinsulated walls and floor, plus a heat-resistant glass window that can quickly be closed in an emergency. Eight d-c motors, totaling nearly 1300 hp, are re quired to operate the various hoist, trolley, and bridge motions of each of the three Fairless hot metal cranes. All are rugged mill-type motors of the so-called `"600 Scries"; all were made by Elliott's Crocker-Wheeler Division. The tabulation below shows the various crane motions and the C-W motors which power them: i the sides hoist trolley, which is equipped with a 75-ton and a 20-ton auxiliary hoist, traveling on the lower inside girders. Tie single-hook 75-ton auxiliary hoist is used principally to tilt the la- = after ii has been emptied of mol ten steel in order to clean out the slag. d |Smjller 2't0n auxilijT hoist is i" t0 carry various lighter loads iu- 1 to l^e shop operations. Operations Speed (ft/min) Main Hoist 1st Auxiliary Hoist 2nd Auxiliary Hoist Main Trolley Auxiliary Trolley Bridge 9.3 28.5 42.2 76.0 127.0 300.0 C-W Motor 2--265 hp. Frame 618 1--200 hp, Frame 616 1-- 65 hp, Frame 610 1-- 65 hp, Frame 610 1-- 33 hp. Frame 606 2--200 hp. Frame 616 rOWTtRFAX.SUM.UEH 1954 PAGE