Our Engineer pictured here inside the lift shaft on the car top is inspecting the coated SDR’s suspension ropes on a passenger / goods lift manufactured by Orona Lifts.

SDR is an abbreviation for ‘small diameter rope’ and the coating is a thermoplastic polyurethane (TPU) sheath which completely envelops the steel load rope.

Small diameter lift ropes require smaller diameter drive sheaves thus leading to smaller gearless drive units resulting in space saving and reduced manufacturing & running costs.

It’s difficult to see in these photos as the TPU sheathing is transparent but as these ropes begin to age a brown discolouration occurs which is quite natural.

TPU coating sheathing can also be coloured blue or green too.

TPU coated lift suspension ropes offer the following advantages:

Reduced wear to the rope and sheave due to the coating separating the working surfaces resulting in:

Longer service life.

Lower noise

Less vibration

Improved comfort in lift car