Guidelines for the installation of rotation resistant rope:
- Follow instructions for removing rope from a reel or coil
- Use a pulling grip fitted with a swivel when pulling new rope through the reeving system with a used rope. This practice will prevent residual twist in the pulling rope from being transferred to the new rope. The pulling rope should be the same lay direction as the new rope.
- Back tension should be applied to the payoff reel of the new rope to insure a tight even spooling drum.
- Operate the new rope through several complete cycles at light load. This will allow the rope to adjust gradually to operating conditions.
The proper operation of rotation resistant ropes depends on maintaining the torsional balance of the rope during use. Imbalance between inner and outer layers of the rope can be caused by twist induced in the rope as a result of undesirable operating conditions. Some common causes of twist are: improper fleet angles sheave alignment or poor spooling. Odd part reeving with off center attachment of the dead end to the block or improper reeving can cause misalignment of the traveling block including the twist into the rope.
Although these ropes are classified as rotation resistant it must be realized that some slight rotation may occur, particularly in the early stages of rope life. This rotation may result in undesirable ‘cabling’, in multipart systems or twisting of the load in single part. If this occurs it is advisable to relieve the twist by disconnecting the most accessible end of the rope and then reconnecting it. In some applications swivels are used to relieve accumulated rope twist during installation and periodically during operation. The swivel should be locked off after twist is relieved to prevent uncontrolled rotation.
The use of an open swivel (allowed to rotate freely) continuously during operation of the rope is a practice that must be carefully considered. Open swivels are not recommended for use with 8x19, 19x7 and 19x19 rope classifications. For other multi strand constructions consult the rope manufacturer for recommendations regarding the use of swivels.
Special Constructions
Many wire rope designs have been developed by the wire rope industry for use on special applications. Within the scope of this application it would not be feasible either to list or describe all the possible rope design variations. Some of the more popular special constructions are described in the following section. Information is provided about the construction and mechanical features of these ropes to assist the user.