Esko Aulanko of Kerava and Jorma Mustalahti of Hyvinkaeae, Finland, have assigned to KONE Corp. of Helsinki, Finland, U.S. Patent No. 7,461,721 dated December 9, 2008. An elevator hoisting rope set suspends a counterweight and an elevator car. The elevator has one or more rope pulleys provided with rope grooves, one of said rope pulleys being a traction sheave that moves the hoisting ropes. At least the traction sheave has against the hoisting rope a coating adhesively attached to it and increasing the coefficient of friction. At least the traction sheave and the hoisting ropes together form a material pair in which the hoisting ropes bite into the traction sheave, maintaining a grip sufficient for the operation of the elevator even in an exceptional situation where the coating increasing the coefficient of friction on the surface of the traction sheave is lost.
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