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.
[Illustration: FIG. 97a. DATA RELATIVE TO MANILA TRANSMISSION ROPE AND
SHEAVES]
========+========+===========+=========+=========
| | | |
| | | |
| | | |
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.
[Illustration: FIG. 98.]
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.
[Illustration: FIG. 99.]
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.
[Illustration: FIG. 100.]
[Illustration: FIG. 101.]
[Illustration: FIG. 102.]
[Illustration: FIG. 103.]
[Illustration: FIG. 104.]
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 ^.