A jib crane is a type of crane with a horizontal arm that supports a hoisting mechanism, and is bolted to the ground or wall by a support pillar. These cranes are used for everything from loading docks to heavy-duty pickup trucks. It is very important not to overload a jib crane because if the crane mechanism breaks, it will most likely damage or destroy the cargo as well, and any people standing near the apparatus.
Determine what the model number of your crane is. You can find the model number on smaller cranes on the vertical pillar, often on a label near the bottom of the pillar. On larger cranes, the model number is in the control cockpit, on or under the control panel.
Contact the manufacturer of the crane to request the operation manual for your model of crane.
Consult the manual for your model of crane for the load capacity rating, which will probably be in pounds for small cranes, and tons for larger cranes.
Even though most cranes are overengineered, do not, under any circumstances, place more load on the crane than it's rated to handle.