Chapter XVIII: Wire Rope Transmission 143 (4)

THE splicing of a transmission rope is an important matter; the points on which the success of the splice, and incidentally the drive, depend being the length of the splice, which in turn depends upon the diameter of the rope and which is given in the table (Fig. 97a); the diameter of the splice, which should be the same as the diameter of the rope; the securing of the ends of the strands of the splice, which must be so fastened that they will not wear or whip out or cause the overlying strands to wear unduly; and the workmanship of the splice, which should be the best it is possible to secure. When splicing an old and a new piece of rope, the new piece should be thoroughly stretched, for, at best, it is an exceedingly difficult task on account of the stretch and difference in diameter of the rope.

========+========+===========+=========+=========
| | | |
| | | |
| | | |
Diameter| Square |Approximate|Breaking | Maximum
of Rope| of |Weight per |Strength,|Allowable
in |Diameter| Foot, | Pounds |Tension,
Inches | | Pounds | | Pounds
--------+--------+-----------+---------+---------
1/2 | .25 | .12 | 1750 | 50
5/8 | .2906 | .16 | 2730 | 80
3/4 | .5625 | .20 | 3950 | 112
7/8 | .7656 | .26 | 5400 | 153
1 | 1. | .34 | 7000 | 200
1-1/8 | 1.2656 | .43 | 8900 | 253
1-1/4 | 1.5625 | .63 | 10,900 | 312
1-1/2 | 2.25 | .77 | 15,700 | 450
1-3/4 | 3.0625 | 1.04 | 21,400 | 612
2 | 4. | 1.36 | 28,000 | 800
2-1/4 | 5.0625 | 1.73 | 35,400 | 1012
2-1/2 | 6.25 | 2.13 | 43,700 | 1250
========+========+===========+=========+=========
+====================+========+==========
|LENGTH OF SPLICE | |
| IN FEET |Smallest| Maximum
+------+------+------+Diameter| Number
| 3- | 4- | 6- | of | of
|Strand|Strand|Strand|Sheaves |Revolutions
| | | | in |per Minute
| | | | Inches |
+------+------+------+--------+-----------
| 6 | | | 20 | 1060
| 6 | | | 24 | 970
| 6 | 8 | | 27 | 760
| 6 | 8 | | 32 | 650
| 7 | 10 | 14 | 36 | 570
| 7 | 10 | 16 | 40 | 510
| 7 | 10 | 16 | 45 | 460
| 8 | 12 | 18 | 54 | 380
| 8 | 12 | 18 | 63 | 330
| 9 | 14 | 20 | 72 | 290
| 9 | 14 | 20 | 81 | 255
| 10 | 16 | 22 | 90 | 230
+======+======+======+========+==========

The illustrations and instructions for making standard rope splices are taken, by the courtesy of the American Manufacturing Company, from their "Blue Book of Rope Transmission."

There are many different splices now in use, but the one that experience has proved best is what is known as the English transmission splice. In describing this we take for our example a four-strand rope, 1-3/4 inches in diameter, as spliced on sheaves in the multiple system. The rope is first placed around sheaves, and, with a tackle, stretched and hauled taut; the ends should pass each other from six to seven feet, the passing point being marked with twine on each rope. The rope is then slipped from the sheaves and allowed to rest on shafts, to give sufficient slack for making the splice.

Unlay the strands in pairs as far back as the twines _M_, _M′_, crotch the four pairs of strands thus opened (Fig. 98), cores having been drawn out together on the upper side. Then, having removed marking twine _M_, unlay the two strands 6 and 8, still in pairs, back a distance of two feet, to _A_; the strands 1 and 3, also in pairs, being carefully laid in their place. Next unlay the strands 5 and 7 in pairs, to _A′_, replacing them as before with 2 and 4. The rope is now as shown in Fig. 99. The pair of strands 6 and 8 are now separated, and 8 unlaid four feet back to _B_, a distance of six feet from center, strand 6 being left at _A_. The pair of strands 1 and 3 having been separated, 3 is left at _A_, as companion for 6, strand 1 being carefully laid in place of strand 8 until they meet at point _B_. The two pairs of strands 2-4 and 5-7 are now separated and laid in the same manner, every care being taken, while thus putting the rope together, that original twist and lay of strand is maintained. The protruding cores are now cut off so that the ends, when pushed back in rope, butt together.

The rope now appears as shown in Fig. 100, and after the eight strands have been cut to convenient working lengths (about two feet), the companion strands are ready to be fastened together and "tucked"; this operation is described for strands 2 and 7, the method being identical for the other three pairs. Unlay 2 and 7 for about twelve to fourteen inches, divide each strand in half by removing its cover yarns (see Fig. 101), whip with twine the ends of interior yarns 2′ and 7′; then, leaving cover 2, relay 2′ until near 7 and 7′, here join with simple knot 2′ and 7′, Fig. 102. Divide cover yarns 7, and pass 2′ through them, continuing on through the rope _under_ the two adjacent strands, avoiding the core, thus locking 2′, Fig. 103. _In no event pass 2′ over these or any other strands._ Half-strand 7′ must now be taken care of; at the right of the knot made with 2′ and 7′, 2′ is slightly raised with a marlin spike, and 7′ passed or tucked around it two or three times, these two half-strands forming in this way a whole strand. Half-strand 7′ is tucked until cover 2 is reached, whose yarns are divided and 7′ passed through them and drawn under the two adjacent strands, forming again the lock. The strand ends at both locks are now cut off, leaving about two inches, so that the yarns may draw slightly without unlocking. This completes the joining of one pair of strands, Fig. 104. The three remaining pairs of strands are joined in the same manner.

After the rope has been in service a few days, the projecting ends at locks wear away, and if tucks have been carefully made, and the original twist of yarns preserved, the diameter of the rope will not be increased, nor can the splice be located when the rope is in motion.

XVIII

WIRE ROPE TRANSMISSION[13]

WIRE ropes are extensively and successfully used in the horizontal and inclined transmission of great power of unlimited amount, the advantages over hemp rope belting being: driving at very long distances, comparatively small loss through slipping and the possibility of driving in the open air.

[13] Contributed to Power by C. Boysen, M. E.

Vertical transmission of power, on account of the weight of the rope, is excluded.

Formerly the material used in the manufacture of the wires was best charcoal iron, but now almost exclusively tough crucible-steel wires are used, as steel wire ropes are stronger, do not stretch as much, and last longer than iron ropes.

The wire ropes consist of six strands of from six to twenty wires each, and the strands to form the rope are woven in the opposite direction to the wires in the strand. In the center of each strand and in the center of the rope a cotton core is placed. These cores are of the greatest importance, for by reducing the friction of the wires against each other, they serve to increase the lifetime of the rope, which, according to the strain on the rope and the size of the smallest pulley, is from one to three years.

To prevent rusting, the wire ropes receive a coat of boiled linseed oil, or a hot mixture consisting of three parts of drip oil and one part of resin is applied. This latter mixture at the same time improves the adhesion between the rope and the lining placed in the bottom of the pulleys, thus reducing the loss caused by slipping of the rope. Wire ropes used for the transmission of power should never be galvanized.

The ends of the rope are spliced together, from 10 to 20 feet being necessary for a good splice; great care should be taken that the splice is made by experienced men, and that the rope is made long enough. A rope stretches constantly from the time when placed on the pulleys, the more so when placed on the pulleys tightly. Therefore it has to be made long enough to transmit power without undue tension, and for this reason the distance between the two pulleys has to be long enough and the working strain per square inch of section low enough to allow sufficient deflection in the rope. As a guidance to the amount of deflection necessary, be it said that even in a short drive the deflection of the rope, when not running, should not be less than 2 feet; and for a distance of 400 feet between pulley centers, the deflection of the rope when running should be 5 feet in the driving rope and 10 feet in the driven rope.

Either the top or the bottom rope may be the driving one, the former being preferable; but the ropes should never be crossed.

Power can be transmitted to a distance of 6000 feet and more without great loss; but as two pulleys should on no account be more than 500 feet apart, intermediate stations are placed along the road.

Precautions should be taken against the possibility of the rope swaying. This may be caused either by the influence of the wind, by a bad splice, by the rope wearing too much, by the pulleys not being balanced well or by the pulleys not being in the same plane. It is of importance that the pulleys be exactly in line, and careful attention should be given to the construction and placing of the bearings. Although the bearings are not strained excessively, the steps are usually made long and movable. The connection between the shaft and the pulley is best made by means of tangential keys.

Some engineers, when two ropes are found necessary for the transmission of the power in question, use pulleys containing two grooves each, and make the same kind of pulleys for the intermediate stations of long-distance driving; whereas others advise a separate pulley for each rope, both being connected with each other by a clutch.

The diameter of the smallest pulley has to be large enough in comparison with the diameter of the rope or the thickness of the single wires used to easily overcome the stiffness in the rope. The larger the pulleys, the longer the rope will last.

The rim of the pulley is V-shaped, and the bottom of the groove is dovetailed to receive a lining of wood, rubber or leather, on which the rope rests. The lining increases the friction and reduces the loss caused by slipping of the rope. Leather is the best lining and lasts about three years. Either old belt leather, well saturated with oil, or new leather, boiled in fish oil, can be taken. It is cut in pieces of the same size as the dovetailed part of the groove, and then placed on and pressed together in the latter. The pressing is done by means of a piece of wood. The last remaining small space in the groove is filled with soft rubber. If the lining has to consist of rubber, this is softened and hammered into the groove. For wood lining, thin blocks of the required size are placed into the groove through a hole provided in the bottom of the rim. This slot is closed by a plate and fastened to the bottom of the rim by means of screws after all blocks have been inserted. The lining has to be turned absolutely true, for which reason the filling is done while the pulley is still in the lathe.

Pulleys up to 3 feet in diameter are built with cast-iron arms; whereas larger pulleys have wrought-iron arms made of round iron, cast in the rim and boss. Pulleys under 8 feet 6 inches in diameter are made in one piece, if for other reasons it is not necessary to have them in halves.

Guide pulleys are used for long ropes, especially if there is not sufficient hight above the ground. The guide pulleys are of the same construction as the main pulleys, and for the driving rope they are also made of the same diameter. The diameter of the guide pulleys for the driven rope can be made from 20 to 25 per cent. smaller.

The breaking strength of unannealed wires per square inch of section and according to thickness and quality is: For iron wires from 70,000 to 110,000 pounds, and for steel wires from 110,000 to 130,000 pounds. For thinner wires a higher value is taken than for thick ones.

The diameter of the wires used for making ropes for transmitting power is from 0.02 to 0.1 inch, and on account of the stiffness, no wires above the latter size should be used. A rope consisting of a greater number of thin wires, besides being stronger is more pliable and lasts longer than a rope of the same area consisting of a less number of thicker wires.

INDEX

A

American Mfg. Co., 136

B

Bauer, Chas. A., 54

Beams to carry stringers, finding, 42

Bearings, locating, 3

Belt, building, 94

Belt creep, 106
dressing, 91, 100
comparative test, 102
running off, 101
shifter device upon column, 9
sizes, 132

Belt, leather, selection, 89
marking spliced part, 12
new, putting on, 19, 20
slack, 100
splicing on the pulleys, 81
throwing on, 12
tight, 100
wire-lacing, 12

Belt-clamps, use, 19

Belting and pulley chart, 129

Belting, cleaning, 97
horse-power transmitted, 132, 133
use and abuse, 99
width, 132

Belts, cleaning, 88
keeping clean, 94
leather, care and management, 89
splicing, 72
main line, 5
taking-up, 11

Bird, Prof. Wm. W., 106, 107

Blue Book of Rope Transmission, 136

Board for use in lining countershaft, 35, 36

Boiled linseed oil in wire rope, 144

Bolt and nut for moving pulleys, 62
for hanger, size, 40

Bolt, preventing turning, 11, 21

Boysen, C., M. E., 143

Brands, effect on leather, 90

Breaking strain on shaft, 28
strength of unannealed wires, 146

Bunsen burner, use in moving pulley, 62

Bushing, split, 2

C

Center drive for heavily loaded shaft, 7
stock, 90

Chart, belting and pulley, 129

Cleaning belting, 97

Clutch, rim-friction, arrangement, 5

Clutches, coupling, 31
tightening while shafting is in motion, 7

Collars, split wood, 3

Compass saw, use in locating beams, 45

Contact, extra, securing, 17

Continuous-wrap system of rope drive, 112
-wrap system with direct-acting tightener, 113

Core, cotton, of wire rope, 143
rope, 124

Countershaft, lining, 32, 33, 35, 36, 37

Couplings, flanged bolt, 3

Cresson Co., Geo. V., catalog, 132

D

Deflection of rope, 144

Diameter of splice, 136
rope, 124, 135
of wires for transmission rope, 147

Diameters, pulley, 131

Differential action on ropes, 109, 112, 116

Disks for plumb-bob, 49

Distance of power transmission by wire rope, 144

Dixon, Walter E., M. E. 72,, 89

Dressing, waterproof, for belts, 91

Driving an overhead floor, 6

E

Elbow bolts, 46

Emery cloth for packing, 23, 24

End drive compared with center drive, 7

English transmission splice, 136

Evans, William, 102

F

Farmer, T., Jr., 102

Fastening strands of splice, 136

Fiber, rope, 124

Filled belts, 91

Flanged bolt couplings, 3

G

Gasoline blow torch, use in getting oil out of belt, 88

Gluing a joint, 85

Greene, F. S., 122

Guide pulleys, 146

H

Hanger adjustment, securing, 40, 41
bearing, repairing worn end, 14
positions, marks, 3

Hanger, removing to take off pulley, 63
sliding out of wall box, 1

Hangers, crosswise of shaft, 42

Hangers not allowing vertical adjustment, 3

Heads of hemp, 127

Hemp, 125, 127

Herrman, Chas., 1, 21, 32

Holman, A. G., M. E., 129

Hook bolts, 46

Horse-power transmitted by belting, 132, 133

Hoyt, R., 108

J

Joints in leather belt, 95

Journaled end of shaft, proper length, 1

K

Kavanagh, Wm., 61

Kent's Handbook, 132

Kinks, practical, 61

L

Lag screws, boring for, 46

Laps of leather belt, length, 90
of leather belt, thickness, 94

Leather belts, care and management, 89
selection, 89

Leather-cutting tool, 75

Leather, length for belt, 90, 95

Length of splice, 135

Leveling shafting, 54, 58

Line, leveling, 52
setting, 51

Lining a countershaft, 32, 33, 35, 36, 37
of pulley, wire rope transmission, 145
shafting, 30, 54

Loosening pulley that has seized, 26

Lubrication of rope, 123

M

McBarnes, Wm. H., 99

Main shaft belted to engine and to countershaft, 8

Marks on ends of shafts, 2
to show hanger positions, 3

Mounting dynamos and motors, 18

Mule belt, 13

Multiple-rope system, 108

N

Neatsfoot oil as belt dressing, 103

O

Oil, boiled linseed, on wire rope, 144
effect on belt, 92
getting out of belt, 87

P

Packing to secure good clamping fit, 23, 24

Plank to use in sliding hanger out of wall box, 1

Plumb-bob, 49, 58
-bob method of lining countershaft, 38

Point slipping, 92

Power transmission by wire ropes, distance, 144

Practical kinks, 61

Pulley and belting chart, 129
diameters, 131, 145
lining, wire rope transmission, 145
shafts holding arrangement and adjusting contrivance, 13
speed, 129

Pulley, cast-iron, moving, 62
driving, location, 5
loose, 61
seized, loosening, 25, 26

Pulleys for wire rope transmission, 145, 147

Pulleys, guide, 146
loosening, 65, 67, 70
moving, 62
removing, 65, 67, 70
solid, 4
split, 5

R

Rope, core, 124
diameter, 124, 135
differential action, 109, 112, 116
drives, 108
fibers, 124
lubrication, 123
splicing, 135
strands, 124
transmission, 135
new scheme, 115
ordering, 122

Ropes, slack, 111
tight, 111

Rusting of wire rope, preventing, 144

S

Scrapers for removing glue, 74, 75

Scrapers, turning edge, 76, 77

Seizing of pulley, 25

Separate-rope system, 108

Set-screws, use, 23

Shaft, breaking strain, 28
causes of breaking, 16
preventing turning, 15, 16
repairing break, 17
journaled off to act as collar, 2
length of journaled part of end, 1

Shaft line, space between end and wall, 3

Shafting, apparatus for leveling and lining, 54
hints, 1, 21, 32
leveling, 58
line, turning up, 49
lining, 30
testing alinement and level, 29

Shafts of light-working counters, marring, 10

Sheaves, 135

Sheet iron for packing, 24

Sizes of belts, 132
of rope, effect, 110

Slack ropes, 111

Slip of belt, legitimate, 107

Space between end of shaft line and wall, 3

Speed, pulley, 129

Splice, diameter, 136
English transmission, 136
fastening strands, 136
length, 135

Splice opener for heavy belts, 72

Splice, wire rope, 144
workmanship, 136

Spliced part of belt, marking, 12

Splicing belt on the pulleys, 81
board, 78, 79
leather belts, 72
rope, 135

Split bushing, 2

Split-pulley, tightening, 23

Split wood collars, 3

Steel for sharpening scraper, 76

Stillson wrench, use, 22

Strands of rope, 124

Stretchers, position, 49

Stringers, locating beams to carry, 42

Stringers of drop hangers, thickness, 38

Superior 2ds hemp, 127

Swaying of rope, preventing, 145

T

Take-up for rope drive, 112
-up sheave for rope drive, 116

Testing alinement and level of shafting, 29

Tight ropes, 111

Tightener, automatic, for rope drive, 113

Tightener for 31-rope drive, 117
system, dangerous, 6

Tightening ropes, 112

Timbers of boarded-over ceiling, locating, 42, 45

Tin for packing, 24

Tool for leveling shafting, 58

Tools for splicing leather belts, 72

Transmission rope, 135
rope, ordering, 122

Transmission, wire rope, 143
rope, deflection of rope, 144

Traveling take-up for rope drive, 112

Tucking strands, 139

Turning edge of scrapers, 76, 77
up line shafting, 49

V

V-shaped rails, for mounting dynamos and motors, 18

Vertical adjustment for hangers, 3

W

Water, effect on belt, 92

Width of belting, 132, 133

Willis, Geo. F., 115

Wire diameter, for transmission rope, 147

Wire-lacing a belt, 12

Wire rope, splice, 144
transmission, 143

Wrench, proper way to use, 22

Z

Zebu manila hemp, 125, 127

Transcriber's Notes:

Obvious typos were silently corrected.

Archaic and variable spelling has been preserved.

Variations in hyphenation and compound words have been preserved.

Italics are shown thus: _sloping_.

Bold type is shown thus: =shout=.

Small capitals have been capitalised.

Punctuation has been preserved as it appears in the
original publication.

Due to space constraints the table on p135 has been split.

Subscript shown by underscore _, superscript by ^.