MONORAILS AND TELPHERS. Machines of the type usually known as monorails are installations which handle rela tively light loads, i.e., from r cwt. to I ton net, such a device is shown in fig. 1. The trolley can be combined with a lifting block which may be manually, mechanically or electrically operated. Telphers are on a similar principle but are always electricall) driven. They are divided into monorail telphers and bottom flange telphers, the latter being also called transporters. In the monorail type the machine travels on a "bulb-headed" or "bridge" rail, secured to the top of an I-beam ; in the bottom flange type the running wheels are duplicated and travel on both sides of the bottom flange of an I-beam. Monorails proper and bottom-flange telphers are both also known as runways. All types under the above headings serve, so to speak, for interdepart mental vehicular goods traffic. While ordinary vehicular traffic runs on a pair of rails on the ground, the receptacles or skips of monorails and telphers are sus pended from one overhead rail. Overhead traffic has the advan tage over that on ground rails in that the track does not en cumber the ground, which is a matter of importance, particu larly in congested aisles and passages on the factory floor. The overhead rail from which the receptacles are suspended occu pies space which is of lesser value. Conditions obtain in many cases which make it absolutely imperative to convey on a path well above ground. Overhead monorail tracks are unobstructed and therefore offer less resistance to the movement of the receptacles, which, having generally only two wheels, run more easily than those on ground rails, which have four, because the friction is less. Monorail receptacles when electrically driven can be at any height above ground, or if pushed by a man walking on the ground they may be just high enough for him to reach them. A single to-and fro track may be employed when only one unit of the telpher machine, as the rolling stock is called, can be used; but a double or endless track, i.e., joined together at the two terminals, which passes all the points to be served, is the ideal solution, because it provides for one-way traffic and a number of units can travel in unbroken succession. This is of particular importance in the case of overhead traffic, where individual loads are handled rather than a train of several, as is the case with ordinary ground traffic. The track can be so arranged as to lead in and out of shops, also round buildings, at relatively sharp angles and even slight inclines, and may also be provided with branch lines. It may be supported from the ceiling or some other part of the building or, if in the open, from steel or wooden structures. In small installations the track may be a light rail of selected sec tion or it may consist merely of a flat iron bar. The receptacles are suspended from a two-wheeled trolley or runner on the rail. When switches are employed great care must be taken to leave no open track ends, since they might be the cause of serious acci dents. A variety of such switches are now on the market.
The First Telpher.—The telpher was invented in 1882 by Professor Fleeming Jenkin, and the name given by him, derives from two Greek words, tele, far; and pherein, to carry. In work ing out his invention Professor Jenkin collaborated with Pro fessors Ayrton and Parry. The first installation was erected at Glynde, in Sussex, on Lord Hampden's estate, and was for hand ling clay from a brick-field. It was a perfect success. The cost of transport was a little under 4d. per ton-mile. The track in this first example, unlike that of the modern telpher, consisted of two steel cables and not a rigid rail. The material was transported by an electrically operated tractor having ten carriers, five of which were pushed and the other five pulled. A modern telpher is a self-contained, electrically operated unit and consists essen tially of a suitable bogie or trolley, running on an overhead rail, from which is supported one receptacle to carry the load. The bogie is fitted with, and propelled by, an electric motor, which collects its current by a small trolley pole from a single, double or triple live rail supported on the track structure. The telpher may be what is known as a "man-telpher" (though frequently driven by a woman), i.e. accompanied by an attendant who, from the cab, starts, stops, receives or dumps the load and returns for a further one, or it may be controlled automatically, so that it travels when released at the loading platform to a predetermined, though variable destination, where it dumps its load automatically and returns again to the starting point. Man-telphers are gener ally fitted with one or two electric winches for picking up loads from ground level at any part of the line and laying them down at any other. Monorail telphers are suitable for heavy loads of, for instance, from 1 ton up to 5 tons net ; and the speeds of travel may be anything from 5ooft. up to I ,000ft. per minute, according to the nature and length of the run. The lifting speeds range from 6oft. per minute with heavy loads, to goof t. per minute with light loads and long lifts. For loads up to a maximum of 1 ton the bottom-flange telpher is more suitable. Speeds of travel are slower than those mentioned above. Botb types are equally applicable in their particular fields. Theoretically, there is no limit to the conveying distance of a telpher, but for economic reasons the allied "ropeway" (q.v.) is generally preferred where distances of a quarter of a mile and over have to be traversed. Monorail telphers are frequent in gas and electricity undertakings.
Automatic Telphers.—Automatic telphers are often provided with a perfect automatic block system, so that each passing tel pher establishes its own connections and no second machine can enter the line within a predetermined distance from the one in front, while if that one stops all succeeding machines will keep the same distance apart. These automatic devices are, as yet, very little used in Great Britain; they are, on the other hand, employed frequently on the Continent.
(G. F. Z.)