The Mechanical Handling and Storing of Material

AERIAL CABLEWAYS OR CABLE-CRANES 321 The trolleys are built in three sizes to take skips of 15, 28, and 43 cub. ft. capacity. The corresponding diameters of the main or rail cables are and | in. An approximate idea of the capacity and working, cost may be formed from the fact that the trolley can make the double journey of a track of 250 ft. long in one minute. At this speed the largest skip can convey over 600 cub. yds. of material in ten hours. Three men are required to manipulate such a plant, and the coal consumption of the driving engines is said to be 1 to 1J tons per day under ordinary conditions. Cableways of John M. Henderson & Co.—In these cableways the carriage or carrier (see Fig. 461) is usually pro- vided with three wheels. These are supported on an articulated frame which allows them to accommodate themselves to any Fig. 460. Large Scale View of Tripper. curves the rope may assume. Some of Henderson’s cableways are fitted with a device by means of which the skip can be-emptied at any point by the operator in charge. The arrangement for this consists of an additional narrow drum on the winding gear, and a small wire rope between the traveller and the rear end of the. skip similar to-Lidgerwood’s ; also special slings, hoisting blocks, and controlling apparatus at the engines. Fig. 461 represents the usual design of the Henderson traveller or load carriage, and the accompanying numbering refers to the different parts shown in the diagram. Two interesting examples showing the utility of the cableway for different classes of work are illustrated in Figs. 462 and 463. Fig. 462 represents three Henderson cableways with a span of 750 ft. each, and for Fig. 461. Henderson’s Load Carrier. 1. Main Cable. 2. Button Rope. 3. Travelling Rope. 4. Hoisting Rope. 5. Load Carriage Wheel on Levers. 6. Load Cariiage Wheels. 7. Hoisting Pulley. 8. Hoisting Block. 9. Small Guide Pulley for Travelling Rope. 10. Button-Rope Pulleys. 11. Large Guide Pulley for Travelling Rope. 12. Rope Carrier Pulleys. 13. Pin for Rope Carrier Pulleys. 14. Rope Carrier. 15. Button. 16. Tension Screw and Nut. 17. Oil-Pot. loads of 5 tons, the respective heights of head and tail towers being 60 and 50 ft., the engine cylinders having an 18-in. stroke, and being 11 in. in diameter. 1 hese cableways are used by Messrs Pearson & Co., Ltd., for excavating work at the Dockyards, Malta. The terminal on either bank and the progress of the excavating work can be clearly seen. Similar installations have been or are being employed on dock construction at Gibraltar, Hong-Kong, Buenos Aires, and Simon’s Bay, South Africa. Fig. 463 shows a similar cableway with a span of 1,000 ft. for loads of 2^ tons. Ihe 21