Messrs. Wilkins & Co., the well-known wire rope manufacturers, are much to the point, and deserve the attention of all interested : Qualities of Steel Wire.-There are four qualities of steel wire used for wire-rope making, viz. : Breaking Strain. "Plough Quality Steel Wire.-Ropes made of good patent steel wire of a tensile resistance equivalent to 80 to 85 tons per square inch, usually prove more satisfactory than those made of plough quality steel wire, which is always very speculative, especially when run at high speed and round pulleys except those of very ample diameter. 66 Specifications. Users of wire ropes would often buy more advantageously by first submitting specification of working to the wire ropemaker for advice as to the kind of rope best adapted to any particular work. Specifications should state: 1. Length of rope. 2. Size of gear. 3. Speed. 4. Load, exclusive of rope. 5. If for wet workings. 6. Rate of incline. 66 7. Particulars of curves. Working Loads.-Many ropes are seriously damaged by being overloaded. The maximum working load at average speed, including weight of rope, should not exceed an eighth of the breaking strain, or at high speed a tenth of the breaking strain. 66 Gear. Great care should be taken that wire ropes are not worked round drums or over pulleys (at brows or angles of whatever degree) of insufficient circumference, and that they do not strike against any hard substance while in motion. Storing.-Wire ropes must be very carefully stored. They should on no account be placed on the ground, but on sound planks raised several inches from the earth, so that they may be free from damp. They should also be covered with a tarpaulin and regularly inspected from time to time. "Uncoiling.-Much care should be taken in uncoiling wire ropes, to prevent kinking. The coil should not be laid stationary, but should be placed on a turntable or reel. Unwind from the outer end. "Grease. To prevent corrosion, all working ropes should receive a regular dressing thoroughly laid on by passing the rope between roller brushes well fed with wire rope grease. "Starting. The greatest strain on a rope being at the moment of starting, every care should be taken to insure perfect steadiness of movement, as jerking is ruinous to ropes. Changing Ropes.-A rope may be changed from a smaller to a larger drum, but not from a larger to a smaller one. "Lightning Conductors.-Undoubted evidence exists of the explosion of firedamp in collieries through sparks from atmospheric electricity being led into the mine by the wire ropes of the shaft and the iron rails of the galleries. Hence the headgear of all shafts should be protected by proper lightning conductors, as suggested in the Report of the Lightning Rod Conference, 1881. "Safety. Nothing costs too much on which life depends." The following tables of breaking strains and working loads of ropes. and also the weights and strengths of chains, are issued by Mr. Frederick W. Scott, another well-known rope manufacturer : COMPARATIVE TABLE OF THE DIFFERENT QUALITIES OF STEEL WIRE ROUND ROPES, SHOWING BREAKING STRAINS AND WORKING LOADS. 3 ---1 2 2 2 2 2 333 334 4 10 10 10 42 6 12 5966 མལ་ 12 7 The weights of ropes given are for wire cores in strands and main core of hemp. From 3" to 7" the weights are for ropes made compound. The weights of compound ropes vary according to construction. For hemp cores in the strands deduct th for sizes down to 33". For wire main core add th to the weights given above. 16 172 2 2 2 2 2 7 COMPARATIVE TABLE OF THE DIFFERENT QUALITIES OF STEEL WIRE FLAT ROPES, SHOWING BREAKING STRAIN AND WORKING LOADS. The weights of ropes given are for wire in centre of each strand, if made hemp centres, deduct about th. CONDUCTORS OR GUIDE RODS. 00-0000 2 2 333 +++ 55 1:0 223333+++456 13 14 15 2 3 19 21 22 23 27 30 32 33 +100 31247. 38 41 X X X X X X X X X X X X X X X X X X 44 Self-acting incline ropes, and hauling ropes frequently require splicing as a result of breakage. Pit ropes, are, for obvious reasons not spliced. A common method of repairing a broken rope is by a shackle joint. The method of capping a rope, shown in Fig. 68 (A), is to a large extent followed, but the rings over the joint would be greatly in the way and are therefore not used. A socket with bow having been riveted to one end of the broken rope, the other Fig. 69.-REPAIRING BROKEN Wire-rope. end is similarly treated and the two ends are joined by means of a link passed through the two loops and carefully closed, see Fig. 69. A rope joined in this way may last a long time, but there is an increased amount of friction caused by the joint passing over the rollers. The following method of splicing ropes is advised by Mr. Frederick W. Scott, of Reddish, near Stockport : "In splicing a wire rope the greatest care should be taken to leave no projecting ends or thick parts in the rope. Heave the two ends taut, with block and def 123 έδα 4 5 6 Fig. 70.- -ROPE-SPLICING. fall, until they overlap each other about twenty feet. Then open the strands of both ends of the rope for a distance of ten feet each; cut off closely the main heart or cores (see Fig. 70), and then bring the open bunches of strands face to face, so that the opposite strands interlock regularly with each other. 66 Secondly.-Unlay any strand, a, and follow up with the strand 1 of the other end, laying it tightly into the open groove left upon unwinding a, and making Fig. 71. ROPE-SPLICING. Fig. 72. the twist of the strand agree exactly with the lay of the open groove, until all but about six inches of 1 are laid in, and a has become twenty feet long. Next cut off a within six inches of the rope (see Fig. 71), leaving two short ends, which should be tied temporarily. "Thirdly.-Unlay a strand, 4, of the opposite end, and follow up with the strand f, laying it into the open groove, as before, and treating it precisely as in the first case (see Fig. 72). Next pursue the same course with b and 2, stopping, however, within four feet of the first set; next with e and 5; also with c, 3, and d, 6. We now have the strands laid into each other's places, with the respective ends passing each other at points four feet apart, as shown in Fig. 73. 5 4 F! 4 F! 2 Р 2 Fig. 73.-ROPE-SPLICING. "Fourthly. These ends must now be secured and disposed of, without increasing the diameter of the rope, in the following manner :-Insert marlinespike through the centre of rope and cut out six inches of main core, and place the end of 1 under a into the place occupied by the core, and then cut out the core in the same way on the right and place the end of a into the place of the core in like manner. "The ends of the strands should be straightened and lapped with fine hemp seizing before being put in. Then dispose of the remaining ends alternately in the same manner. After having done this, the rope should be well closed, and any unevenness or irregularity can be taken out by pounding it with a wooden mallet. "In cases where ropes are heavily worked, when tucking in the ends pass No. 1 over a and b over No. 1. This mode of splicing ensures a very tight grip, and has been found to answer admirably." This method of splicing is most effective, but as it occupies a considerable time to perform it is not usual to splice the rope during the working hours of the day. To do so then would interfere with the pit traffic, more especially in the case of a hauling rope, and seriously reduce the day's landings and workmen's earnings. At well-conducted collieries, spare shackles are kept ready for use at a moment's notice. If a rope break, the rope repairer, provided with the shackles, joins the broken ends in accordance with Fig. 69, and the pit is soon in full operation again. But this is regarded only as a temporary expedient for getting the day's coal out with the least possible reduction in output. When operations for the day cease, and at a time when the temporarily joined rope is not in use, the rope splicer descends the shaft, takes off the shackles and carefully performs the splice shown in Figs. 70-73. SHAFT SIGNALS.-Separate and distinct signals are required between the pit top and every stopping or landing place in the pit and vice versa. The system may be either the ordinary one of wires working bells or hammers, or by electric signals, speaking tubes, or telephones. Whatever system is employed a code of signals is necessary. In deciding on a system of signalling the importance of some means of communication between the men in the cage while being drawn up or let down the shaft, should be kept in view Electricity offers the best means of attaining this object in dry shafts, as each cage may work through a wire, or a couple of wires placed close together, within easy reach of those in the cage. Besides the facility thus offered for the occupants of the cage to signal to the surface in case of accident, electric signals would be convenient to those engaged in the examination or repairing of the shaft. An electrical shaft signal has been invented and patented by Mr. W. Armstrong, jun. It is an electrical appliance by which signals can be interchanged between those in a cage either in motion or at rest and the engineman. An insulated core is carried in one of the strands of the winding rope, the lower end being attached to a ringing key in the cage, and the upper to a commutator on the engine shaft, through which the |