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ELEVATOR ROPE
 
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Extension of Wire Rope

When a wire rope is subjected to load, it’s constituent wires and strands try to pull down with accompanied reduction in overall size and an increase in wire rope length. This phenomenon is termed as Construction Stretch and is very difficult to determine empirically because it’s extent depends primarily on the magnitude of applied load, rope construction and core besides other factors of smaller influence. These factors vary for each instance and are very difficult to quantity exactly. However, based on years of manufacturing experience and available data, the table given below summarizes approximate value of construction stretch.

The major proportion of construction stretch occurs immediately after installation of elevator ropes and gradually fades away with cycle of usage, the lighter the load the higher is the time needed for stabilization.

In addition to the above, when loaded, the rope extends in a manner characterizes by proportionality, that is proportional to strain. This extension of wire rope is recoverable, meaning thereby that the rope length becomes same when the applied load is removed, and is termed as Elastic Stretch. A reasonable estimate of elastic stretch may be made by using the values and expression given below :

Elastic Stretch (mm) = [ W x L ]/ [E x A]

W - A p p l i e d L o a d ( N )

L - R o p e L e n g t h ( m m )

E - Modulus of Elasticity (N/mm )

A - Metallic Area of Rope (mm )

 

  • ‘E’ value may be taken as 70,000 N/sq mm for 6 stranded fiber core rope ; 55,000 N/sq mm for 8 strand fibre core ropes and 65,000 N/sq mm for 8 & 9 strand steel core ropes.
  • Metallic Area of Rope is available with rope manufacturer.

 

ELEVATOR ROPE

Pre-stretching

Pre-stretching is a technique for removing the constructional stretch, prior to use, by cyclically loading the cable until it shows no constructional stretch. It must however be remembered that repeated handling (particularly coiling / uncoiling) of the wire rope reduces the effect of pre-stretching, although temporarily, which is realized again when the wire rope is loaded after installation.

  CONSTRUCTIONAL STRENGTH TOTAL STRENGTH
AS MANUFACTURED WIRE ROPE
6X19 Class with Fibre Core 0.25 - 0.50 % 0.40 - 0.75 %
8X19 Class with Fibre Core 0.50 - 0.75 % 0.70 - 1.05 %
8X19 Class with Steel Core
9X19 Class with Steel Core
0.30 - 0.60 % 0.45 - 0.85 %
Pre-stretched wire rope
6X19 Class with Fibre Core 0.10 - 0.25 % 0.25 - 0.50 %
8X19 Class with Fibre Core 0.20 - 0.35 % 0.40 - 0.65 %
8X19 Class with Steel Core
9X19 Class with Steel Core
0.10 - 0.30 % 0.25 - 0.60 %

 

  • The values stated above are sensitive to the influence of applied load and other test/site site condition and has been given for general guidance only.
  • The stretch of wire rope in an installation is greatly influenced by the efficiency of wire rope tensioning. If the tension is not equal on each rope of the set then each will stretch in proportion to the applied load and is likely to create vibration and will adversely affect rope performance.

 


Rope Class 8x19 With Steel Core
 

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Preferred Rope Construction

8 - strand wire rope with

  • Seale
  • Filler or
  • Warrington strand construction And aSteel Core (IWRC) at the center
    • Very Good Bend Fatigue values
    • Very Good Elongation properties
    • Better Contact on drum and sheaves
TABLE 4
As per
ISO 4344
Nominal
Rope
Diameter
#Equiv.
Nominal
Rope Diameter
Approx. Mass Minimum Breaking Force
Rope Grade
Dual Tensile Single Tensile
*1180/1770 1370/1770 **1570/1770 1570 1770
mm in. kg/100m kn kn kn kn kn
8 5/16 26.0 33.6 35.8 38.0 35.8 40.3
9   33.0 42.5 45.3 48.2 45.3 51.0
9.5 3/8 36.7 47.4 50.4 53.7 50.4 56.9
10   40.7 52.5 55.9 59.5 55.9 63.0
11 7/6 49.2 63.5 67.6 71.9 67.6 76.2
12   58.6 75.6 80.5 85.6 80.5 90.7
12.7 1/2 65.6 84.7 90.1 95.9 90.1 102
13   68.8 88.7 94.5 100 94.5 106
14   79.8 102 110 117 110 124
15   91.6 118 126 134 126 142
16 5/8 104 134 143 152 143 161
18   132 170 181 193 181 204
19 3/4 147 190 202 215 202 227
20   163 210 224 238 224 252
22 7/8 197 254 271 288 271 305

Note: Rope size & breaking force not shown in the table, may be available on request and prior confoirmation
#Equivalent Nominal Rope Diameter (inch') is for referance only as the same has been superseded by metric units (mm)
*1180/1770 rope grande is equivalent to traction steel grade, 1370/1770 may also be used
**1570/1770 rope grade is equivalent to EHS steel grade.

 


Rope Class 8x19 With Steel Core
 
TABLE 5 Nominal
Rope
Diameter
Approx.
Mass
Minimum Breaking Force
Rope Grade
Dual Tensile single Tensile
1370/1770 1570/1770 1570 1770
mm kg/100m kn kn kn kn
8 26.0 35.8 38.0 35.8 40.3
9 33.0 45.3 48.2 45.3 51.0
10 40.7 55.9 59.5 55.9 63.0
11 49.2 67.6 71.6 67.6 76.2
12 58.6 80.5 85.6 80.5 90.7
13 68.8 94.5 100 94.5 106
14 79.8 110 117 110 124
15 91.6 126 134 126 142
16 104 143 152 143 161
18 132 181 193 181 204
As per
EN 12385.5
19 147 202 215 202 227
20 163 224 238 224 252
22 197 271 288 271 305

Note: Rope size and breaking force not shown in the table, may be available on request and prior conformation

TABLE 6 Nominal
Rope
Diameter
# Equiv.
Nominal
Rope
Diameter
Approx.
Mass
Minimum Breaking Force
Rope Grade
Dual Tensile Single Tensile
*1180/1770 1370/1770 **1570/1770 1570 1770
in. mm ib./ft. ibs ibs ibs ibs ibs
US
Customary
Units
5/16 8 0.17 7,550 8050 8540 8050 9060
3/8 9.5 0.25 10,660 11,330 12,070 11,330 12,790
7/16 11 0.33 14.280 15,200 16,160 15,200 17,130
  1/2 12.7 0.44 19,040 20,260 21,560 20,260 22,930
9/16 14.3 0.56 24,140 25,700 27,330 25,700 28,970
5/8 16 0.70 30,130 32,150 34,170 32,150 36,200
Wire Rope conforms to
the applicable
section of
ISO 4344
11/16 17.5 0.84 36,150 38,480 40,930 38,480 43,380
3/4 19 0.99 42,720 45,410 48,340 45,410 51,030
13/16 20.6 1.16 50,100 53,320 56,720 53,320 60,120
7/8 22 1.32 57,100 60,930 64,750 60,930 68,570

Note: Rope size and breaking force not shown in the table, may be available on request and prior conformation
#Equivalent Nominal Rope Diameter (mm’) is for reference only
*1180/1770 rope grade is equivalent to Traction steel grade, 1370/1770 may also be used
**1570/1770 rope grade is equivalent to EHS steel grade

 

Rope Class 6x19 With Fiber Core
 

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Preferred Rope Construction

8 - strand wire rope with

  • Seale
  • Filler or
  • Warrington strand construction And a fIBER Core at the centre
    • 6X19 is most used as Governor Rope
    • Good Bend Fatigue values
    • Good Elongation properties
TABLE 7
As per
ISO 4344
Nominal
Rope
Diameter
# Equiv.
Nominal
Rope
Diameter
Approx.
Mass
Minimum Breaking Force
Rope Grade
Dual Tensile Single Tensile
*1180/1770 1370/1770 1570 **1770
mm in. kg/100m kn kn kn kn
6   12.9 16.3 17.8 18.7 21.0
6.3 1/4 14.2 17.9 - - 23.2
6.5   15.2 19.1 20.9 21.9 24.7
8 5/16 23.0 28.9 31.7 33.2 37.4
9   29.1 36.6 40.1 42.0 47.3
9.5 3/8 32.4 40.8 44.7 46.8 52.7
10   35.9 45.2 49.5 51.8 58.4
11 7/16 43.4 54.7 59.9 62.7 70.7
12   51.7 65.1 71.3 74.6 84.1
12.7 1/2 57.9 72.9 79.8 83.6 94.2
13   60.7 76.4 83.7 87.6 98.7
14   70.4 88.6 97.0 102 114
14.3 9/16 73.4 92.4 - - 119
15   80.8 102 111 117 131
16 5/8 91.9 116 127 133 150
17.5 11/16 110 138 - - 179
18   116 146 160 168 189
19 3/4 130 163 179 187 211
20   144 181 198 207 234
20.6 13/16 152 192 - - 248
22 7/8 174 219 240 251 283

Note: Rope size & breaking force not shown in the table, may be available on request and prior confoirmation.
#Equivalent Mominal Rope Diameter (inch’) is for referance only as the same has been superseded by metric units (mm)
*1180/1770 rope grade is equivalent to traction steel grade, 1370/1770 may also be used
**1570/1770 rope grade is equivalent to EHS steel grade

 

Rope Class 6x19 With Fiber Core
 
TABLE 8 Nominal
Rope
Diameter
Approx.
Mass
Minimum Breaking Force
Rope Grade
Dual Tensile single Tensile
1180/1770 1370/1770 1570 1770
mm kg/100m kn kn kn kn
6 12.9 16.3 17.8 18.7 21.0
6.5 15.2 19.1 20.9 21.9 24.7
8 23.0 28.9 31.7 33.2 37.4
9 29.1 36.6 40.1 42.0 47.3
10 35.9 45.2 49.5 51.8 58.4
11 43.4 54.7 59.9 62.7 70.7
12 51.7 65.1 71.3 74.6 84.1
13 60.7 76.4 83.7 87.6 98.7
14 70.4 88.6 97.0 102 114
15 80.8 102 111 117 131
As per
EN 12385-5
16 91.9 116 127 133 150
18 116 146 160 168 189
19 130 163 179 187 211
20 144 181 198 207 234
22 174 219 240 251 283

Note: Rope size and breaking force not shown in the table, may be available on request and prior conformation

TABLE 9 Nominal
Rope
Diameter
# Equiv.
Nominal
Rope
Diameter
Approx.
Mass
Minimum Breaking Force
Rope Grade
Dual Tensile Single Tensile
*1180/1770 1370/1770 1570 1770
in. mm ib./ft. ibs ibs ibs ibs
US
Customary
Units
1/4 6.3 0.10 4,020 4,420 4,620 5,220
5/16 8 0.15 6,500 7,130 7,460 8410
3/8 9.5 0.22 9,170 10,020 10,520 11,850
7/16 11 0.29 12,300 13,470 14,100 15,890
  1/2 12.7 0.39 16,390 17,940 18,800 21,180
9/16 14.3 0.49 20,770 22,760 23,820 26,750
5/8 16 0.62 26,080 28,550 29,900 33,720
11/16 17.5 0.74 31,030 34,080 35,670 40,240
3/4 19 0.87 36,650 40,240 42,040 47,440
13/16 20.6 1.02 43,170 47,230 49,430 55,760
Wire Rope conforms to
the applicable
section of
ISO 4344
7/8 22 1.17 49,240 53,960 56,430 63,620
15/16 23.8 1.37 57,620 63,090 66,030 74,450
1 25.4 1.56 65,580 71,800 75,150 84,720
1-1/16 27 1.76 74,040 81,070 84,850 95,660

Note: Rope size and breaking force not shown in the table, may be available on request and prior conformation
#Equivalent Nominal Rope Diameter (mm’) is for reference only
*1180/1770 rope grade is equivalent to Traction steel grade, 1370/1770 may also be used
**1570/1770 rope grade is equivalent to EHS steel grade

 

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