What feature must all running sheaves be equipped with?

All running sheaves must be equipped with a means for lubrication to ensure their proper functioning. Lubrication reduces friction between moving parts, which is essential for minimizing wear and tear, preventing overheating, and enhancing the overall longevity of the equipment. This is particularly important in a hoisting context where sheaves are subjected to dynamic loads and continuous movement. Proper lubrication helps ensure smooth operation and safety, as it reduces the risk of mechanical failure that could lead to accidents or equipment malfunction.

While features like ball bearings, heat-resistant materials, and lifting straps can be useful in specific applications, they are not universally required for all running sheaves. The necessity of a lubrication mechanism applies to all types of running sheaves, making it a fundamental characteristic aimed at maintaining operational efficiency and safety in hoisting operations.