Overhead bridge cranes are essential machines in steel manufacturing, paper mills, and a number of other factories across the US. Even if you are a seasoned overhead crane operator, there are a few minor details and common misconceptions that any operator would benefit from touching up on. Here are four important safety tips for overhead crane operators.
Always Test Hoist Brakes When Operating Near Capacity
Even in situations where you have lifted the same load before, you need to test the hoist brakes every time before lifting a load that is near the capacity of the crane. The hoist brakes are the primary fail-safe disc brakes that are responsible for preventing the load from falling in the event of a power failure.
To test the hoist brakes before operating the crane, attach the load to the pulley and lift it a few inches off the floor. Then, turn the master switch to the off position to make sure the load will hold. If there are any signs of slipping, turn the power back on and gently lower the load to the floor. The crane should not be used until this problem is repaired.
Secondary Brakes Will Not Hold the Load on Most Cranes
A common misconception about overhead cranes is that they have a secondary set of brakes that can hold the load if the first set fails. Older cranes were equipped with mechanical load brakes that were capable of keeping the load suspended. However, these were only suitable for stopping small loads, and generated a lot of heat that could damage the crane.
Modern cranes are equipped with regenerative brakes that function differently from mechanical brakes. Instead of keeping the load suspended, they lower it to the floor at the standard operating speed. While this is safer than a heavy load in free fall, it can still cause serious injury or death for any workers that are under the load when it falls. Never rely on the secondary breaks to justify working beneath a suspended load.
Check the Wire for Signs of Damage Before Operating
While some types of damage to the steel cable wire can be easy to spot, there are more subtle symptoms of a weak cable that you need to watch out for. Obviously, any signs of fraying or uncoiling of the wire will indicate that it is weakened. You should also look out for sections of the wire that are narrower than the rest, as this can be a sign that the wire has been stretched near its breaking point.
Do Not Use the Reverse Button to Decelerate the Trolley
Another habit that experienced operators may have carried over from older machines is the tendency to use the reverse button to stop the trolley. While the practice of "feathering" the reverse button by lightly tapping it to decelerate the crane was once a standard technique, it is no longer usable on modern machines for safety reasons as well as mechanical limitations.
Most modern cranes from sites like http://wazeeco.com/ have built-in soft stop technology that slows and stops the trolley after it has traveled a predetermined distance. This is safer because it eliminates the element of human error from the process of stopping the loaded trolley on time, and also because it is easier on the engine of the crane. Soft stop mechanisms do not generate as much heat as reverse button deceleration, reducing the risk of internal component failure.
No matter how excellent your crane operator training and experience is, it can never hurt to revisit the fundamentals. Keep these tips in mind to avoid simple crane operating mistakes and create a safer working environment for you and your co-workers.Share
26 September 2014
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