The Mechanical Handling and Storing of Material

ROPEWAYS 269 A line on this system, of about 1,800 yds. in length, is at work in Japan, running mostly at an incline of 1 in 1|. It is used to carry ore from the upper terminal to the lower. Such is the power generated by the descending loads, that it has been found necessary to absorb the greater part of it, so as to render the line amenable to the control of a hand brake. With this view a hydraulic brake was introduced, in which the revolving fan drives the water against fixed vanes which again repel it. By this means about 50 H.P. was absorbed, and the speed regulated to a nicety by adjusting reaction vanes against which the water impinges. A variation of this system is that of a single fixed rope, on which one carrier, hanging from the fixed rope, is drawn to and fro by an endless hauling rope. This kind of ropeway has been found useful under conditions where moderate quantities have to be transported in heavy loads or pieces, or where spans of considerable length have to be worked over. Inclines up to 1 in 1 can be worked, and a span up to 2,000 yds. used, while loads up to 5 tons may be carried. The endless hauling rope is operated by any available power, the driving gear being arranged with reversing motion so that the direction in which the carrier runs may be changed as required by the attendant. The fixed rope is supported on posts spaced at intervals varying with the nature of the ground, while the hauling rope is carried on pulleys fitted with guide bars and placed in the centre of the post over which the carrier passes, the posts, of course, being so arranged as to allow of the carrier clearing them. The return hauling rope may be supported on an outside pulley mounted on an arm of each post. The hauling rope is attached to the carrier head by suitably placing a pendant which causes it to pass under the saddle transom. A ropeway, erected on this system by Messrs Bullivant, is at work on Table Mountain, at the Cape of Good Hope, and has a length of 5,280 ft. This line commences at the sea level, and following the ground on posts spaced about 300 ft. apart, takes a span of 1,500 ft., rising to a projecting rock 1,480 ft. above,the starting point. Resting upon this support at this point, it again makes a span of 1,400 ft. to an upper terminal 2,170 ft. above the lower one. Another type of ropeway is that which consists of two fixed ropes with an endless hauling rope, in which one carrier will run in one direction, while the other runs on a parallel rope in an opposite direction. Such a ropeway can be used over long spans where individual loads amounting to 5 tons have to be transported. It would be suitable in cases where the ropeway could be worked by gravity, the descending load moving by its own weight, while the empty carrier ascends. In such cases spans of 2,000 yds. or more may be safely negotiated, and loads of 6 tons carried. Gripping and Other Coupling Devices,1 by means of which the carrier is attached to the hauling rope, are some of the most important details of a double rope- way, and must fulfil the following conditions : — Firstly, the attachments must have such a grip on the rope that the carrier can ascend inclines of 45° in safety without tendency to slipping. Secondly, the hold or grip on the rope must be entirely by friction, as any bending of the hauling rope by the coupling will inevitably shorten the life of the rope. Thirdly, the apparatus should be so arranged that the amount of grip is adjustable according to the circumstances, taking the wear of the rope and climatic and atmospheric influences into account; and 1 The facts and illustrations are taken from an article by A. Pietrkowski in Stahl und Eisen, 18th November 1908.