The overhead and gantry are the two most common types of industrial cranes. The overhead crane has a movable bridge that carries a movable trolley supporting the hoisting mechanism, traveling on an overhead fixed runway structure.
A gantry crane is very much like the overhead crane except for the fact that the bridge for carrying the trolley or trolleys is rigidly supported on two or more legs. It mostly runs on fixed rails or other similar runways, usually on the ground.
The overhead and gantry crane safety standards and operating procedures for both machines are grouped because of the similar traveling and hoisting characteristics.
Pre-Operation Check
Each machine must be tested before an operation, no matter how frequently or infrequently it is used. Listen and look for any sound or movement that could signal damage by operating the crane a few feet in each direction. Check the emergency stop button to make certain it is working properly by slowly raising the load block until it trips the upper limit switch. But above all, do not ignore any red flag no matter how little it might be.
Operation Safety | Gantry Crane Safety | Overhead Crane Safety
- Always, I repeat, always, perform a below-the-hook device inspection. This entails checking for damage: spreader bars, shackles, pulleys, slings.
- Make it a habit to start the lift slowly to minimize the swinging of the load. Ensure that the rigging job is properly holding, and there is no slipping. Then Raise the load high enough to clear any obstacles in one smooth motion. Do all this in a smooth motion avoiding any abrupt moves.
- Remember, overhead cranes are designed only for vertical lifts. If the load is pulled sideways, serious damage or catastrophic crane failure could result. Once the load is properly raised, you can move the load to the desired location but remember that you should never carry a load over the top of someone. When the crane is in position, then you can slowly lower the load to its set-down location.
- If the load is free-swinging then it is advised that tag lines should be affixed to at least two corners of the load. This ensures that the load can be turned without standing under or close to it while adjusting its position by hand.
- If you come across any sort of emergency, shut off the main switch that powers the crane. Always make sure you are familiar with the location of the main disconnect switch and that it is easily accessible. In case you are using a crane that does not have a disconnect box nearby, the stop button on the control pendant should be yours to go to as it cuts off all power to the crane.
Required Safety Practices
Never move a load over co-workers nor permit co-workers to walk underneath the load. Ensure that you return the load block to its designated location after use. Also, make sure that you do not leave the load block low enough for someone to run into.
Continuously observe equipment for any sign of problems during operation and most of all, do not ignore the tiniest glitch. Always pay attention to what you are doing. The smallest of distractions could be fatal. And above all, do not operate such machines if you are intoxicated.