Wire Ropes Under Bending and Tensile Stresses - Wire Ropes: Tension, Endurance, Reliability - page 303

Example 3.11 Elevator for residential building

Data:
Nominal load Q = 800 kg
Car mass F = 1,000 kg
Rope mass = 50 kg
Wire rope Warrington 6 9 19-IWRC-sZ
Nominal strength R 0 = 1,570 N/mm 2
Rope diameter d = 10 mm
Number of bearing ropes n = 6
Rope bending length l = 6m
Diameter of traction sh. D T = 400 mm
Diameter of deflection sh. D R = 450 mm
Speed v = 1 m/s.

D T

D R

G

F

Q

Analysis:
Most trips made by the car come or go to the ground
floor. Therefore the sections of rope running over
the sheaves determine rope endurance in elevators.
For one trip from or to the ground floor the loading
element (bending cycle) for the traction sheave is
w

loading sequence

T =1 .

and for the deflection sheave
Rope tensile forces:
For traction sheaves with form grooves Holeschak
( 1987 ) evaluated the endurance factor f N3 (Table 3.15 ) under the supposition of a
cabin permanently loaded (force factor f S5 = 1) with 50 % of the nominal load.
Under the same condition the rope tensile force for the traction sheave and for the
deflection sheave is

loading elements

S ¼ S T ¼ S S ¼ ð F þ 0 : 5 Q þ S Þ g
n

f S1 f S2 f S3 f S4w

Force factors from Table 3.12
For sliding guidance f S1 = 1.1

For rope efficiency f S2 & 1

For unequal forces in the parallel bearing ropes f S3 = 1.25

For acceleration or deceleration f S4 = 1.12

f S4w = 1 + 1 (1.12 - 1)/2
= 1. 06.