Abstract: A crane assembly includes an anti-two block system having a rigid body, a sensor configured to detect upward loading of the body, and a spring biasing the body to a pin of a sheave. The body includes a base, two extensions projecting perpendicularly upward from the base and extending outside the sheave on opposite sides thereof, and a fitting on upper ends of the extensions. The fitting couples to the pin of the sheave such that the body is configured to rotate about the pin. The crane assembly further includes a controller comprising logic configured to prevent movement of a hook in response to a signal from the sensor of the anti-two block system. The weight of the body of the anti-two block system rotates the body such that the extensions are substantially aligned with a cable between an end of a boom and a hook as the boom rotates.

Abstract: A crane assembly includes an anti-two block system having a rigid body, a sensor configured to detect upward loading of the body, and a spring biasing the body to a pin of a sheave. The body includes a base, two extensions projecting perpendicularly upward from the base and extending outside the sheave on opposite sides thereof, and a fitting on upper ends of the extensions. The fitting couples to the pin of the sheave such that the body is configured to rotate about the pin. The crane assembly further includes a controller comprising logic configured to prevent movement of a hook in response to a signal from the sensor of the anti-two block system. The weight of the body of the anti-two block system rotates the body such that the extensions are substantially aligned with a cable between an end of a boom and a hook as the boom rotates.