NEIEP Mechanics Practice Exam

How does a 4 to 1 reeving system impact the load capacity of a hoist?

1. Halves the capacity

2. Reduces capacity to one-fourth

3. Doubles the capacity

4. Maintains original capacity

The correct answer is: Doubles the capacity

In a hoisting system, reeving refers to the arrangement of ropes or cables around drums or pulleys, which directly affects the mechanical advantage available when lifting a load. A 4 to 1 reeving system means that for every four units of distance the rope moves, the load attached moves one unit of distance. This configuration provides a mechanical advantage by distributing the load over multiple segments of the rope. In a 4 to 1 system, the load is essentially divided by the number of segments of rope supporting it. Therefore, if a hoist can lift 1000 pounds with a single line, using a 4 to 1 reeving system allows it to lift 4000 pounds, as the load is equally shared among four segments of rope. Thus, the capacity is effectively doubled compared to a straight single line lift. This mechanical advantage makes lifting heavier loads feasible with the same amount of force exerted by the operator. It is essential to consider factors such as the strength of the rope and the hoist specifications to ensure safe lifting operations, but from a purely mechanical standpoint, this reeving system allows for greater load capacity, making it functionally equivalent to doubling the capacity when compared to a single line lift, while maintaining the same