How to Lift a Load with CG Misaligned to Lifting Device

Swish! Nothing but net from behind the 3-point line! _{^{It even looks like his illustration!}}

Use slings of different lengths. Or use chain set up so it can not slip. Or set your lunch box on the weight to balance it.

My favorite set up is a double chain sling, where each chain has a chain hook on it. You can adjust each chain to the lift in question.

Chain shortenering hooks are the ticket. Wihout lifting the load, you adjust the sling lengths so that the hook is above your centre of mass.

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Does it matter if the load swings sideways as soon as it clears the floor? It will with the load leveler or a diagonal pull located at the center of load.

You could add load to the left end to move the center of load to be under the lift point.

1st, is this a homework project?

There are a variety of ways to do this, but essentially you need to grab the object from multiple points (which the load-leveler does). This can be far more involved than it seems as the CG on many loads is not readily apparent and it can shift as you start lifting.

If you are going to be lifting this object anywhere where there is the remotest possibility that it could hit someone (or their property) if it fell you need to hire a professional with a substantial liability insurance policy (or get one for yourself) so you don't find yourself paying someone's potential lifetime earnings, pain and suffering, etc...

The easiest way to lift without losing control of the object is to use a spreader on the cable hook. It offsets and distributes the weight which allows for better control even if off center

Two chain blocks so you can udjust the lengths of either side to keep the load level. It is a cheaper option.

I have found these to be helpful: Load Balancer

Even so, you will always get a lateral tension and unwanted lateral acceleration when the friction between the load and ground are reduced. Such events can be very dangerous, even toppling the lifting mechanism.

Where ever possible it is preferred to get the CG's aligned even if it means adding counter weights.

I agree with URAD. If this is a large bulk, the best procedure is to use counterweights. And the load balancer is a good idea if it is feasible.

We design lifting fixtures with adjustable features. This way we can manage any CG problem. Make sure your lifting device is capable to handle the load.

You can buy lifting slings with adjustable features already implemented.

Dear Sir,

You use one Chain Block to adjust the weight on one side, left or right.

sawadhkm

Please provide full details of your application. Wt. in kg., item to be lifted, part of which machine?. After hearing from you we can suggest you solution.

Is the CL of the Load the same as the CL of the Load's weight? Does the CL of the Lifting Device line up with the CL of the Load?

Draw a free body diagram and you could find the lenght of each sling, starting with the principle that the moments in both of the sides of your load should have the same value, the weight of your load(divided by 2) times by the distance to the first support eye equals the weight of the load (divided by 2) times by the opposite distance.

Simpliest way, if the hoist has a single lifting point (such as a hook or shackle), is to use two slings (or chains) of equal length hung from the hoist lifting point to each lifting eye on the load where the slings go directly from the hoist hook to the load lifting eye.

If more than 2 lifting eyes are on the load, then seperate slings should be attached from the hoist hook to each load lifting eye. As long as the slings are of equal length and the hoist hook is located above a polygon formed by the a line from each lifting eye to the next one, the load will lift level.

Good Luck, Old Salt