Purpose of wire rope for suspended cradle
Special-purpose galvanized wire rope for lifting equipment for construction-purpose suspended cradle used in the facing construction, decoration, installation of curtain wall, washing of high-rise and multi-floor buildings, window-cleaning equipment.
Features: produced with constant-length wires, linear contact structure, super-high strength, small diameter tolerance, strong windability.
Precautions for use:
During transportation: handle with care, prevent packing impacted or damaged; protect against damp and rains. Wire ropes shall be stored in dry and well-vented indoor environment.
Spool shall be adopted to back track wire-releasing direction, avoiding additional stress generated
Welding of the wire end shall be done when the rope is relaxed and free of stress.
The direction in which the rope goes shall be attended during construction, thus to avoid additional stress and wire rope bent.
Precautions for use of wire rope for suspended cradles
1、Wire rope shall be free of bending, grease, dirt, welding slag and ablation. Using work wire rope and safety wire rope as low-voltage circuit for welding is forbidden.
2、Wire rope for suspended cradles shall be of result and mechanical properties as required. Wire ropes for different hoists and lifting machines shall not be mixed up for use. Wire rope inspection and discarding shall be as required by GB5972-86; those meeting discarding standard must be discarded.
3、Wire rope must be properly maintained. No greasing is allowed during operation; prevent the rope from contacting acidic and alkali materials as well as corrosive gases during storage, thus to prevent contamination and corrosion.
The wire rope shall be replaced immediately in any of the following cases:
a、Wire rope strand apart, kinked, knot loosened, crushed, folded, distorted.
b、Number of broken wires within the length of a wire pitch reaches 5. The discarding standard shall be lowered even more when the wire rope surface is worn or corroded; the rate of lowering is base on the 5 broken wires that each wire pitch allows multiplying by the surface wearing or rust percentage of the wire rope.
c、Obvious rust on wire rope, deep pit on surface, wire rope relaxed.
d、The nominal diameter of wire rope decreased by 6% even when no broken wire is found
e、Wearing of external-layer wires reaches 40% of the diameter
f、Damage or accumulation resulted from heat or electric arc.
4、Before rope reeve, work rope and safety rope must be arranged properly before inserting into hoist and safety lock respectively, avoiding rope twisting or winding.
5、For transportation the machine as a whole, wire ropes shall be coiled and packed first.
6、When releasing wire rope vertically, leave the wire rope freely coiled on the ground and carefully take out the rope head, slip it down slowly along the wall face. Throwing down the rope coil as whole is forbidden. After releasing is completed, separate tangly ropes carefully and then secure them by pressing. Excessive ropes on ground shall be well coiled, tied securely and placed properly.
How to use wire rope for suspended cradle
1、 Reeve of wire rope
The two wire ropes inside the front-beam end of the suspension mechanism are work wire ropes, which shall be reeved into the hoist.
a、Before reeving, check the smoothness and levelness of arc cone surface and the ball head of the welding cap at the reeve-in end of the wire rope; file the stick-outs at the weld edge smooth and insert the wire head into strand.
b、Thread the reeve-in end of the wire rope through roller wheel groove on the swaying arm of the safety lock and then insert it into the rope-in mouth at the top of the hoist until the rope cannot be inserted any more, now lift the wire rope slight and then insert down forcefully into the hoist.
c、 Turn the change-over switch and press the corresponding lifting button to have the wire rope automatically reeled on the driving disc in the hoist in a balanced way.
d、 When wire rope is seen at the rope mouth, guide the rope out with hand carefully to prevent the rope head from knocking at suspension platform or ground, finally causing damages.
e、 Place the wire rope to the outside of the suspension platform with the guiding pulley at the lower side of the hoist bracket
f、 Reeve wire rope through hoists at both ends until the rope is tensioned.

2、 Reeve of safety wire rope
The two wire ropes outside the front-beam end of the suspension mechanism are safety wire ropes, which shall be reeved into safety lock.
When reeving, insert the wire rope into the rope-in mouth of the safety lock, push with hand to allow the rope going through the lock freely; draw out the rope from the lower mouth of the lock until the wire rope is tensioned.
General failure analysis and troubleshooting of wire rope for suspended cradle
Discarding standard for wire rope for suspended cradles:
Discarding of wire rope shall follow the requirements specified in GB5972-86 “Wire rope for lifting applications – Code of practice for examination and discard”. The wire rope must be discarded immediately in any of the following cases:
1、 Galvanized wire rope for suspended cradles must be discarded when there are 3 broken wires within 5cm length or 6 broken wires in 25cm length. In case of enough rope length, the part of broken wires must be cut before reinstallation and use.
2、Wearing of rope diameter reaches 7%.
3、Loosened strands, rope kinked, folded, partially distorted, part of the strands or wires squeezed out etc.
4.Identifiable color change by electric arc is shown on the wire rope surface.

Quality evaluation of wire ropes
The following aspects are considered for evaluating the quality of elevator wire rope
Raw materials selected, including rod coil, cambric, grease, packing material
Reasonable wire rope structure and parameter design; twisting direction and wire pitch as required.
Reasonable drawing and heat-treatment processes; internal structure of uniform performance; residual internal stress completely removed.
Accurate and reasonable parameters for twisting strand, rope twisting pre-deformation and post deformation; rope is treated for tensioning reasonably.
Rope core selected: according to that different elevators are configured with different wire ropes such as general natural fiber core, high-quality natural fiber core, synthetic fiber core, steel wire core, steel wire strand core, semi-steel core etc
Grease and oil percentage: the grease selected shall provide oil film of certain anti-squeezing performance, anti-corrosiveness, friction-enhancing performance, and having proper oil percentage (wires, rope core and wire rope as a whole).
The diameter tolerance, diameter uniformity, and roundness of wire rope as required, especially important for high-speed elevators
Strength and load-bearing capacity of wire rope: hardness of the wire rope shall match with the pulley.
Anti-abrasion and anti-fatigue performance of wire rope: the service life of the wire rope shall be designed in correspondence with the configurations of the elevator.
Surface conditions: surface of the wire rope shall be coated such as galvanized for certain special applications.
Internal structure of the rope shall be free of such defects as broken wires, poor-quality rope core, and poor-quality grease.
Packing neatly wrapped, accurate length, securely tied rope end, packing materials reasonably used