What is the term for the metal wheel in a pulley that the rope runs over?

The term for the metal wheel in a pulley that the rope runs over is "sheave." Sheaves play a critical role in pulleys by reducing friction and allowing the rope to move smoothly. This smooth movement is essential for efficient load lifting and helps in directing the rope as it operates in various rigging scenarios.

The design of a sheave typically includes a groove that matches the diameter of the rope, ensuring a secure fit and proper functioning. Without a sheave, the rope would not be able to rotate freely, which could lead to greater wear on the rope and increased difficulty in lifting or moving loads. Thus, understanding the components of a pulley system, including the function of the sheave, is fundamental for anyone involved in technical rescue operations.