The Works Of Messrs. Schneider And Co.

XL-150 TON ELECTRIC IpREQUENT reference has been made to the 150-ton electric travelling crâne that forms so conspicuous a feature of Messrs. Schneider and Co.’s steel works. The following is a detailed and illustrated description of this very fine machine. The 150-ton crâne, which is illustrated by Figs. 105 and 106, Plate XXIV., and Figs. 107 to 110, was completed in 1893. It is is composed of : 1. Two girders, each 23.4 metres (76.75 ft.) long. 2. Two short cross-girders, supporting the main girders. 3. The wheels carrying the crane. 4. A truck carrying the lifting hook. 5. A three-speed lifting gear. 6. A lowering gear. 7. The traversing gear. 8. The gear for traversing the chain truck. 9. Two electric motors. 10. Two footbridges and a cabin for the attendant. 1. The Main Girders.—These are (see Figs. 105 and 106) of the box type, and are built of steel plates and angles. Each girder is constructed of the following com- ponent parts : Two webplates each 15 millimétrés (.59 in.) thick, .800 metre (2.62 ft.) deep at the ends, and 1.700 metres (5.57 ft.) deep at the middle, the lower edges being parabolic. Both upper and lower flanges have a total thickness of 50 millimétrés (1.97 in.), and are each built up of five 10 millimétré (.39 in.) plates. The angles between the flanges and webs are 100 millimétrés by 100 milli- métrés by 15 millimétrés (3.94 in. by 3.94 in. by .59 in.). The webplates are firmly braced together by internai stiffeners of steel plates and angles, which are spaeed about 2 metres (6.56 ft.) apart, and insure the transverse rigidity of the girders. The upper flanges carry the slides on which the chain truck runs (see Fig. 110). The two girders are braced together at the ends by cast-iron stiffeners, in addition to the short cross-girders on which they rest. At one end of the crâne there are two of these east-iron cross-girders, of which one serves as an abutment for the chain used for traversing the chain truck, and the other is utilised similarly for the support of the lowering gear and the crane traversing gear. At the other end of the crâne there is only one of these cast-iron cross-girders, which carries another chain-wheel for the car-traversing chain, and also has attacheel to it one end of the lifting chain. The two main girders are further braced together by stiffeners built up of plates and angles, arched so as to give room for the passage of the chain truck below them (see Fig. 109). TRAVELLING GRANE. 2. The End Supporting Girders. — The two main girders rest on, and are firmly connectée! by means of gussets to, two stout cross-girders (Fig. 107) built up of plates and angles, which thoroughly brace the main girders together. These cross-girders are carried by the wheels on which the crane runs. 3. The Wheels Carrying the Crane.—The crane rests on eio-ht wheels, four at each end. These wheels have cast- steel centres and wrought-steel tyres of U-section. To insure a fair distribution of load between the wheels, they are connected together in pairs by balance levers as shown in Fig. 108. 4. The Chain Truck.—The chain truck is of cast steel, and supports the shafts on which are mounted two chain wheels, over which the lifting chain passes. It rests on four cast-iron shoes, having strips of anti-friction metal let into them, and which are each .600 metre (1.97 ft.) long. These shoes have oil cups cast in them, which insure a thorough lubrication of the slides at any point. These slides are of cast iron, and are covered for their whole length by cotton belting, which rests on them and protects them from dust. The helts are kept taut by a compensating device, and pass over guide pulleys on the chain car, which thus passes underneath them. 5. The Lifting Gear.—The lifting gear is arrangée! with three speeds—viz., a slow speed of 0.930 metre (3.05 ft.) per minute; a medium speed of 2.510 metres (8.23 ft.) per minute ; and a high speed of 3.610 metres (11.84 ft.) per minute. These three speeds are obtained by means of friction clutches on a countershaft driven by the motors. The clutches are controlled by forked levers operated by screws. The power is transmitted from these clutches by means of gearing to the first motion shaft (see Fig. 106) of the crab On this first motion shaft is a gun-metal pinion, gearing with a wheel running loose on the main crab shaft, but which it can drive by means of a friction clutch. On this shaft are two gun-metal pinions .390 metre (15.3 in.) in diameter, driving two wheels 3.01 metres (9.875 ft.), which are keyed on the same shaft as the chain wheel which operates the lifting chain. A band brake is fitted to the first motion shaft, which supports the load when lifted. This band brake is normally in action, being provided with a counterweiglit to this end, and is sufficiently powerful to prevent the crane working until the weight is raised by means of a foot lever. Thus to raise a load it is necessary in the first place to connect the crab with the motor shaft by means of the friction clutches already mentioned, and then to fvee the brake by means of the foot lever. To stop