In crane operations, which device indicates the maximum height to which a load can be lifted?

The hoist drum indicator is a crucial device in crane operations, as it provides real-time feedback on the amount of cable or rope that has been spooled onto the hoist drum. This device is specifically designed to help operators understand the vertical limitations during lifting operations and to ensure that the load does not exceed the maximum height that can be safely lifted. By showing how much line is available, it aids in preventing situations that could lead to overextension or unsafe lifting practices.

While other devices like the luffing jib limiting device and the boom angle indicator serve important roles in controlling crane movements or ensuring the stability of the crane during operations, they do not specifically indicate the maximum lifting height in relation to the hoist mechanisms. The anti two-blocking device serves to prevent collision between the load block and other parts of the crane, further emphasizing the importance of adhering to safe operating procedures. However, it does not provide a direct measurement of lifting height, which is the essential function of the hoist drum indicator.