National Commission for the Certification of Crane Operators (NCCCO) Lattice Boom Practice Test

To prevent jibs from backwards overturning, it is essential to implement a positive stop. A positive stop is a mechanical device or feature that restricts the movement of the jib beyond a certain point, thus ensuring that it does not move in a direction that could lead to instability or tipping. This safety feature is crucial in crane operations, as it provides an additional layer of protection to maintain control over the jib's position, especially when handling heavy loads or when the crane is operating on uneven ground.

Counterweights, load warning systems, and locking mechanisms serve important roles in crane safety but address different concerns. Counterweights are designed to balance the load and improve stability, but they do not actively prevent backward overturning. Load warning systems provide alerts when the load being lifted approaches the crane's capacity, but they do not physically stop the jib's movement. Locking mechanisms can secure the jib in a certain position but may not prevent all forms of unintended movement if not combined with other safety features.

Thus, the positive stop is the most effective solution specifically tailored to prevent backwards overturning of jibs while ensuring operational safety.