A polyurethane or rubber lining applied to the traction sheave groove to increase rope grip and reduce rope wear in elevator drive systems.
Full Definition
Sheave lagging is a cast or bonded polyurethane or rubber lining applied inside the sheave grooves of a traction machine. It increases the coefficient of friction between the rope and the sheave, improving traction under all load conditions and reducing slippage. Lagging also reduces contact stresses, extending rope fatigue life. Over time the lagging wears and must be replaced as part of the scheduled maintenance programme; worn lagging reduces traction and can cause the rope to slip, triggering the overspeed governor. EN 81-20 mandates adequate traction margin under all car loading conditions.
