How about making it bend in the middle like the newer backhoe booms? This would allow you more clearance for whatever you were trying to lift.
I think this is it.
http://www.ag.ndsu.edu/aben-plans/6191.pdf
The entire index of all plans available is here:
Miscellaneous NDSU Ag CMS
And in case you think you might need one, here's aplan for a Fallout Shelter for 6 people.
http://www.ag.ndsu.edu/aben-plans/5957.pdf
So what is really the question??
The style that require the separate toplink lift more weight, but not as high.
The style that is like a PHD (without using the TL), will lift higher, but wont lift as much weight
How about adding a hydraulic top link for additional functionality?
Just a random thought.
How did you arrive at this generalization?
If the boom is long (tall), the force vectors bring the weight of the load very close to the far ends of the three point lower arms in spite of carrying the load some distance clear of the tractor.
allowing a load nearly equal to the capacity of the lift. Adding a TL does not change this relationship.
The "typical" boom pole does tend to act more like a cantilever than a crane however.
Something I have never liked for moving heavy loads. And if it's light and low, I just use the bucket
How did you arrive at this generalization?
If the boom is long (tall), the force vectors bring the weight of the load very close to the far ends of the three point lower arms in spite of carrying the load some distance clear of the tractor.
allowing a load nearly equal to the capacity of the lift. Adding a TL does not change this relationship.
The "typical" boom pole does tend to act more like a cantilever than a crane however.
Something I have never liked for moving heavy loads. And if it's light and low, I just use the bucket
The top link style lifts a 1:1 ratio, lift the 3pt 2 feet and the boom raises 2 feet.
They type without the top link work like a sissors lift, multiplying the height & speed of the end of the boom pole - depending on the angles used, could lift 2x as high, and require 2x as much power from the 3pt.
--->Paul