How many times the diameter of the rope should the sheave wheel be, at minimum?

The minimum diameter of the sheave wheel should be at least four times the diameter of the rope. This requirement ensures that the rope can bend around the sheave without being excessively stressed or damaged. When a rope bends too sharply, it can lead to increased wear and potential failure due to the sharp radius of curvature.

In the case of a sheave wheel designed for such applications, a diameter that is at least four times greater than that of the rope allows for a safe and effective operation. It helps distribute the load more evenly across the rope fibers, prevents crushing of the rope, and maintains the integrity and performance of the rope over time.

Using a sheave with a minimum diameter of less than four times the rope's diameter could result in a greater risk of damage to the rope, increased friction, and possibly decreased efficiency in lift or pull applications due to the increased wear and tear it would encounter. Thus, adhering to this guideline enhances the safety and reliability of the technical rescue operations involving ropes.