Frequently Asked Questions
Q: Which type of rope should I use on a multi-layer drum winder?
A: Bridon would recommend a FLC (Full Locked Coiled) or a Triangular (Flattened) strand construction.
The construction of these ropes make them best suited for this application as they have a high resistance to crushing.
Also due the smoothness of the circumference of these rope designs, they reduce wear at the cross over contact points as the rope wraps over itself as it is wound onto the drum.
Q: Are there any steps I should take before installing a new hoist rope?
A: It is advisable to measure any pulley wheels (grooves) in the system that the new rope is going to pass over (including deflector pulleys).
A new rope can easily be damaged if the pulley wheel groove is too tight, this will in effect pinch the rope probably causing a wave (spiral) deformity in your new rope.
If left unchecked in a steel pulley, parallel, linear fatigue wire breaks will be found where the contact pressures have become too high, due to a pinch affect.
The diameter of the new rope will be larger than the one to be removed. The old rope will have worn the groove material to the worn rope diameter.
We recommend a clearance of 10 to 12.5% above nominal rope size for steel pulleys and 15 to 20% for polyurethane or other types of lining inserts.
Ideally the pulley wheel groove should support 120 degrees or approximately 33% of the rope circumference.
Defector pulleys should contact the rope at 15% of the rope circumference.
Q: Why do I need opposite lay in my winding ropes on a multi-rope system?
A: Even when recommending ‘non-rotating, rotation resistant ‘ constructions i.e. FLC, Multistrand, all ropes have a tendency to twist when a load is applied.
So to further reduce the affects of rope torque when loaded it is advisable to have a left and right hand laid rope in the winding system.
In a four rope hoist application the ropes should be installed left hand lay, then right hand and left then right hand lay again, not two left and then two right.
This practice is best employed with either rope guides or rigid guides installed in the shaft.
Q: How often should I lubricate my hoist ropes?
A: With a drum winding system it is advisable to apply fresh grease at least once a week, (especially in an upcast shaft) rope life can be significantly improved due to regular maintenance in this way.
The drum end of the rope requires to be greased especially when the underlap conveyance is at the bottom of the shaft, this is when the maximum load is applied and has a tendency to squeeze the lubricant out of the rope and from the contact area on the drum, similarly the area on the drum when the conveyance is at the top of the shaft. During the discharging process the tension in the rope is reduced, this has a ‘sawing ‘effect where the rope contacts the drum which in turn wipes the lubricant from the two contact surfaces.
Good practise should be employed also in a downcast shaft although less frequently. (2 to 4 week intervals)There is less debris and generally less heat to remove or contaminate the surface lubrication.
Hoist ropes on a friction winder should be lubricated individually in turn, ideally on a daily basis so each rope shall be lubricated at least once a week. Due to the need to maintain friction between the rope and drum, specific lubrication only should be used.