Lubricants may be applied by running the engine slowly and allowing the rope to pass through a bunch of waste saturated with lubricant; by rubbing the lubricant into the rope by means of a brush; or by pouring the oil into the groove of the sheave as the rope is run slowly back and forth. A new hoisting rope should be passed through a bath of hot lubricant and thus be thoroughly lubricated.

Haulage ropes are not usually lubricated as thoroughly as hoisting ropes on account of the grease causing slipping of grips and gathering of dirt and dust, but they can be treated with raw linseed oil thickened with lamp-black boiled with an equal portion of pine tar, and the mixture applied while hot. Ordinary black oil, such as is used to oil mine cars and hoisting ropes, can be used on haulage ropes where no friction grips are employed. These mixtures, if fluid, can be poured on the rope as it is run over the sheave, or applied from a leather-lined box filled with oil. Patent lubricants known as cable shields or rope fillers, which fill the interstices between the strands, are often used on tail and main ropes.

General Precautions.-Wire rope is as pliable as new hemp rope of the same strength; the former will therefore run on the same sized sheaves and pulleys as the latter. But the greater the diameter of the sheaves, pulleys, and drums, the longer wire rope will last. In the construction of machinery for wire rope, it will be found good economy to make the drums and sheaves as large as possible.

The tables of wire-rope manufacturers give proper diameters of drum or sheave at from 50 to 65 times the rope diameter; but the expression should more properly be the minimum admissible diameter. For ordinary service, by using sheaves and drums from 75 to 100 times the diameter of the rope, the average life of hoisting ropes will be materially lengthened. For rapid hoisting, during which abnormal strains are most likely to occur, or where a low factor of safety is employed, a sheave diameter of 150 times that of the rope is to be recommended.

Experience has demonstrated that the wear increases with the speed; it is therefore better to increase the load than the speed. Wire rope is manufactured either with a wire or a hemp center; the latter is more pliable than the former, and will wear better where there is short bending.

Wire rope must not be coiled or uncoiled like hemp rope. When mounted on a reel, the reel should be mounted on a spindle or flat turntable to pay off the rope. When shipped in a small coil, without reel, the coil should be rolled over the ground like a wheel, and the rope run off in that way. All untwisting or kinking must be avoided.

A rope should not be changed from a large drum to a small one, for it will not work so well, neither will it last as long. This is also true, but in a lesser degree, of ropes changed from a small drum to a large one. After having been used for some time on a drum, the rope adapts itself to that diameter and resents a change. Rope sheaves should be made to fit the rope, and should be filled in with well-seasoned blocks of oak or other hardwood, set on end; this will save the rope and increase adhesion.

CABLEWAYS AND TRAMWAYS

Cableways. A suspension cableway is a hoisting and conveying device using a suspended cable for a trackway. There are two types: the inclined, or semi-gravity, Fig. 1, and the horizontal, Fig. 2.

The inclined cableway consists of a cable inclined 20° to 22° to the horizontal, and passing over a cast-iron saddle B on top of a tower or frame A. It is anchored by logs D buried about 5 ft. underground, or from iron plugs secured in the rock, when the rock is near the surface. The trolley carriage G runs down the incline of the cableway by gravity until it reaches a stop. A hoisting rope E operated by a winding drum F leads over a sheave pulley e, thence to a pulley in the carriage G, thence to a fall block M, upwards again to a second pulley in the carriage, and downwards again to the fall block. Winding in the rope hoists the fall block to the carriage, the carriage remaining at the lower stop. When the fall block collides with the carriage, both the carriage and the fall block are pulled up the incline cable, and when the carriage arrives at the head-tower, a gate, or hook, O is lowered to hold it in place. The fall block is then lowered and the load discharged. The engine F has usually a 10"X12" double cylinder and a single friction drum 37 in. in diameter.

An endless rope H takes several turns around the sheave J to prevent it from slipping, and both ends are passed over sheaves at the top of the derrick, one end being secured to the front of the carriage, while the other end is taken through the carriage and around the return sheave I and fastened to the rear end of the carriage G. The endless-rope wheel J is provided with a band brake, which, when applied, holds the carriage securely at any point on the cable.

All ropes pass through the supporting trolleys K, which are connected by a chain L. These trolleys follow the carriage by gravity, and the chain may or may not be fast to the carriage.

Instead of chain-connected trolleys, patent button-stop, fall-rope carriers, which are lighter, may be used. These are spaced along an auxiliary rope on which buttons are screwed. The carriers are picked up by a horn on the front of the carriage. These are said to be cheaper for operation than the chain trolleys.

The length of the span for inclined cableways varies from 200 to 1,200 ft. The main rope is from 1 to 21 in. in diameter, the hoisting rope from to in., and the endless rope and in. The rope mostly used is 6 strands, 19 wires to the strand, crucible cast steel. The hoisting rope lasts from 1 to 2 yr., and the main cable from 5 to 10 yr. These cableways are widely used about the slate quarries in Eastern Pennsylvania, where the operating expense for each cable, where two or more are connected with one boiler, is about $5 per da. of 10 hr.; this includes the engineer, steam, and maintenance of the cableway.

The horizontal cableway requires a double friction drum and reversible link-motion engine. It may be operated at any inclination of the carrying cable and either from the high or low point of the support, though, if possible, it should be from the higher end. The endless, or traction, rope, is attached to one of the drums of the engine so that the engineer has complete control of the carriage; hence, because of its greater applicability, this system is supplanting the inclined, although the inclined costs one-fourth less for installation. The method of operation is similar to the inclined. The amount of rope required is the same in each system. A horizontal cableway of the Hamilton Coal Co., near Tarentum, Pennsylvania, has a span of 2,200 ft. The stationary rope is 2,500 ft. long and 24 in. in diameter. The hoisting rope is 4,500 ft. long and in. in diameter. The head-tower is 80 ft. high, the tail-tower is 100 ft. and the rope deflects 80 ft. The skip used holds 3 T. of coal and makes 10 trips per hour. Five men operate the plant and it takes 2 T. of coal for the engine. Based on a capacity of 100 T. per da., the cost of carrying the coal is 13c. per T. For a cableway of average length, 1,000-1,500 ft., the cost of operation should not be one-half the above cost. A cableway, 2,140 ft. long was used in constructing the dam at the power plant at Glens Falls, New York.

One or both towers of a cableway may be mounted on wheels capable of moving on a track at right angles to the cable and the cableway then made to cover a wide territory.

WIRE-ROPE TRAMWAYS

Single Tramways.-A tramway, in America, is a cableway of the horizontal type consisting of a number of spans. In England, the term cableway includes tramways.

Single wire-rope tramways have a single moving rope, which serves to support and advance the load at one and the same time, Fig. 1. This rope passes over suitable sheaves at the intermediate supports, and the load is carried in buckets suspended from it by gooseneck or straight hangers. The hangers are usually attached to the cable by means of a clip, which is either

inserted in the center of the cable or strapped to it. The carriers are often loaded and unloaded while in motion, the loading being accomplished by a traveling mechanical hopper and the unloading by a drop bottom to the bucket. If the line is level, or the grade light, the hangers are provided with box heads filled with wood or leather and rubber, which rest on the rope; the rubber or wood providing sufficient friction to prevent the hangers' slipping. With this system, long spans are evidently out of the question, because with a long span the angle of the rope in the vertical plane, at the supports, becomes so great that the friction will not hold the box head. For all practical purposes, grades exceeding 1:4 are to be avoided; and for steeper grades, to prevent slipping, a clamp or a clip inserted in the rope is used to fasten the hanger to the rope.

The

The single-moving rope tramways carry loads not exceeding 200 lb. speed of the rope for the variety in which the hangers are fastened to the rope may be as high as 450 ft. per min., and for one in which the hanger is loose, 200 ft. per min. The single moving-rope tramway has a capacity up to 200 T. per da., and may be built, say, 1 to 2 mi. long.

Double Tramways.-The more satisfactory and substantial kind of wirerope tramway has one or more fixed ropes, which constitute the permanent way, and an endless traction rope. The loaded carrier travels outwards on one fixed cable and returns by a parallel one suspended from the opposite side of the same supports. The terminals have suitable appliances for loading and unloading the buckets, either by hand or automatically.

The intermediate supports are built of wood or steel framing, with saddles of cast iron a, Fig. 2 in which the fixed cables b rest. The traction rope c is supported (in the absence of a bucket) by the rollers d, set conveniently on the supports. The load is carried in buckets e, or other contrivances suitable for the purpose, which are suspended from a trolly f, which runs on the fixed cables, the wheels of which are large enough to pass over the rope couplings, and

also to clear the saddles. Grips g attach the carriers to the traction rope. These grips may be operated by hand or automatically.

The

This kind of tramway is capable of carrying individual loads up to 1,400 or 1,500 lb., not including the weights of the bucket and hanger itself. speed of traction rope may be from 150 to 350 ft. per min. The capacity is from 200 to 1,000 T. per da. of 10 hr. These figures represent good, safe, practice, but they are not, of course, inflexible.

The maximum length of line that may be built in one section varies largely with conditions of load, spacing of supports, contour of ground, etc. Wire-rope tramways work under great difficulties, and probably 2 to 4 mi. is the economical limit. This has been exceeded, but for a much greater distance the friction becomes too great for economical working of the traction rope. This does not, however, limit the length of tramway which may be built, as the power station may be located at a convenient intermediate point, dividing the line into sections. Several intermediate power stations may be used, and the length of the line greatly increased above the limit given. A tramway at Grand Encampment, Wyoming, is 16 mi. long and carries 40 T. of ore each hour.

GLOSSARY OF ROPE TERMS

Annealed Wire Rope.-A wire rope made from wires that have been softened by annealing and the tensile strength thereby lowered.

Bending Stress.-The stress produced in the outer fibers of a rope by bending over a sheave or drum.

Breaking Strain, Breaking Strength, Breaking Stress.-The least load that will break a rope. These terms are used indiscriminately to mean the load that will break a rope. The stress on a rope at the moment of breaking is the breaking stress, and the strain or deformation produced in the material by this stress is the breaking strain.

Bright Rope.-Rope of any construction, whose wires have not been galvanized, tinned, or otherwise coated.

Cable-Laid Rope.-Wire cables made of several ropes twisted together, each rope being composed of strands twisted together without limitation as to the number of strands or direction of twist. A fiber cable-laid rope is a rope having three strands of hawser-laid rope, twisted right-handed.

Cable. Same as cable-laid rope; a fiber cable consists of three hawsers laid up left-handed.

Cast Steel.-Steel that has been melted, cast into ingots, and rolled out into bars.

Clamp. A device for holding two pieces or parts of rope together by pressure. Clip.-A device similar to a clamp but smaller and for the same purpose. Coir.-Cocoanut-husk fiber.

Compound. A lubricant applied to the inside and outside of ropes preventing corrosion and lessening abrasion of the rope when in contact with hard surfaces.

In

Core.-The central part of a rope forming a cushion for the strands. wire ropes it is sometimes made of wire, but usually it is of hemp, jute, or some like material.

Coupling. A device for joining two rope ends without splicing.
Crucible Steel. A fine quality of steel made by the crucible process.
Drum. The part of a hoisting engine on which the rope is wound.

Elastic Limit. That point at which the deformations in the material cease to be proportional to the stresses.

Elevator Rope.-A rope use to operate an elevator.

Endless Rope.-A rope that moves in one direction, one part of which carries loaded cars from a mine at the same time that another part brings the empties into the mine.

Fiber.-A single thread-like filament.

Flat Rope.-A rope in which the strands are woven or sewed together to form a flat, braid-like rope.

Flattened-Strand Rope.-A wire rope whose strands are flattened or oval. and therefore presents an increased wearing surface over that of the ordinary round-strand rope.

Flattened-Strand Triangular Rope.-A wire rope of the flattened-strand construction in which the strands are triangular in shape.

Fleet.-Movement of a rope sidewise when winding on a drum.

Fleet Wheel.-A grooved wheel or sheave that serves as a drum and about which one or more coils of a haulage rope pass.

Galvanized Rope.-Rope made of wires that have been galvanized or coated with zinc to protect them from corrosion.

Grip Wheel.-A wheel, the periphery of which is fitted with a series of togglejointed, cast-steel jaws that grip the rope automatically.

Guy. A strand or rope used to support a pole, structure, derrick, or chimney, etc.

Haulage Rope.-A rope used for haulage purposes.

Hawser. Any wire rope used for towing on lake or sea. A fiber hawser consists of three strands laid up right-handed.

Hawser-Laid Rope has three strands of yarn twisted left-handed, the yarns being laid up right-handed. Synonymous with cable-laid rope as applied to wire ropes.

Hawser Wire Rope.-Galvanized rope of iron or steel, usually composed of 6 strands, 12 wires each, principally used in marine work for towing purposes. Hemp. A tough, strong fiber obtained from the hemp plant.