What is the purpose of a spreader bar?
When you crane an object, the object is lifted by the crane’s hook. This would be considered the center point of the lift. If you lift an object with more than one strap or chain, all the straps or chains used to lift the object pull towards that center point from wherever they are attached. The further out from the center point they are attached. The more pressure they can exert on an object in a sideways direction. Depending on the weight and strength of the object, that sideways pressure could damage the object being lifted.
To avoid damaging the object being lifted. You sometimes need to change the center point of the lift or create additional center points to reduce or remove this sideways stress on an object.
In the picture above, you will notice that the spreader bar creates two lifting points, one on each side of the generator. These lifting points are outside the width of the unit, which allows the straps to pull away from the generator instead of into it. Due to the size and weight of this generator, the side panels are not strong enough to withstand the force of the straps pulling towards the main crane hook. On this lift, the spreader bar was requested to reduce the odds of damage to the side panels of the generator.
Should they be used on every crane lift?
No. They should only be used on lifts that require them. While many jobs require them, ten times more do not, and they would cause more problems than help. When in doubt, consult a crane operator or an actual structural engineer for their opinion. Please note that a crane operator is NOT an engineer and would ONLY be giving their advice based on their personal experience. You are responsible for advising the crane operator where the safe lifting points are on an object you want lifted. There are many lifts where you want the straps to grip the object for better stability and reduce the odds of an object falling out of the air.
Does every crane truck come with a spreader bar?
No. They are an add-on you must supply or rent for your lift. Many crane companies will rent them out at an additional fee from the crane rental. It is ALWAYS your responsibility to ensure the crane company and operator know they are required before booking your lift, and your responsibility to make sure it is on the order at the time of booking if you are renting one from them. Spreader bars are a separate lifting accessory, not part of the crane truck or your standard crane rental. Failing to do so could double the cost of your lift if they have to reschedule to come back another day with the missing accessory.
When should I consider using one?
When you think the crane straps will apply more pressure to the object than it can handle safely. Remember, spreader bars are designed to move the strap or chain lifting point away from the main hook, to a point that makes more sense for the lifted object.
Would you like to learn more?
Call our crane department to find out more information.