Calculating FEL Lift Capacity

[gladehound]

9'-11' out, and a 1000# scale.....may not even need the pulley

I'm calculating 1,570 pounds of lift 10 ft out but only 751 pounds of curl force at the same place. (Not accounting for the impact of the extended boom's weight which I will measure when I borrow it).

This could create a dangerous situation as my lift cylinders could cause my curl cylinders to go to double the rated operating pressure. I'm not sure at what point something bad happens, but I would think that double is someplace I don't want to go. So I guess I'll choke up on the boom and measure lift at around 6 feet using a pulley with the scale. But I'll measure curl force first to get an idea of where my pressure is (over vs under spec) If it's over spec I need to be even more careful.

I'm starting to think your pressure gauge idea is a real good one.

 

[LD1]

I'm calculating 1,570 pounds of lift 10 ft out but only 751 pounds of curl force at the same place. (Not accounting for the impact of the extended boom's weight which I will measure when I borrow it).

This could create a dangerous situation as my lift cylinders could cause my curl cylinders to go to double the rated operating pressure. I'm not sure at what point something bad happens, but I would think that double is someplace I don't want to go. So I guess I'll choke up on the boom and measure lift at around 6 feet using a pulley with the scale. But I'll measure curl force first to get an idea of where my pressure is (over vs under spec) If it's over spec I need to be even more careful.

I'm starting to think your pressure gauge idea is a real good one.

Pretty simple to do. A male and female coupler. ISO 7241 series B (AKA parker 60 series), a hydraulic tee, a gauge and some fittings.

Leaving it on the lift circuit, gives you a good idea of what weight you are carrying with some "known" references. Also gives you a good idea of your limitations with different counterweights on the back. Very useful.

In your boom pole case, I'd have it on the curl circuit to monitor it while lifting.

 

[bigdeano]

Can you leave the curl cylinders fully extended while using the boom? There'd be no hyd pressure in them then. Maybe the angle would be wrong though.

 

[gladehound]

Can you leave the curl cylinders fully extended while using the boom? There'd be no hyd pressure in them then. Maybe the angle would be wrong though.

Great line of thought. What I could do is leave the curl cylinders in a position that works and run a cable come along from the end of the boom to the middle of the loader arms to take the load off the curl cylinders. Then I could just use the lift cylinders to their full capacity without worrying about my curl cylinders.

Or, if I'm lucky, I'll be able to curl the heaviest thing I need to lift on the end of the boom poll and if so there are no issues.