Your description is the 4 bar link like the picture xring posted. Some backhoe buckets also use this set up.
It dont really increase the range of travel, or the force at all. But what it does is allow a longer cylinder to be used, to gain greater travel, before the cylinder rod contacts the loader arm.
So if your cylinder is 20" long, and all other geometry being equal, a 4 bar wont give any greater travel than pinned straight to the bucket.
I have a mechanical SLL on my ford 5500. It is also smooth as silk.
Probably a good bit smoother than me feathering the curl while raising on my NON-SLL kubota:laughing:
BTW - where is 67PLY? Is he missing all this good stuff. The FEL on my neighbors Versatile is like a hot knife thru butter. Its fun to operate a really BIG tractor.
simply put 4 bar linkages translate motion. Bolt cutters use a 4 bar linkage to multiply cutting force. Large angular travel input and low force translated into low displacement high force output.
I didn't say all linkages were designed to increase force.
Don't believe me here's what kubota has to say about it
"Thanks to an upgraded 4-bar bucket linkage, the rollback and dumping angle has been increased for quicker scooping and dumping."
Still not convinced take some mechanical engineering courses
I didnt contradict myself, but maybe I wasnt clear.
Lets use my kubota for example. Its a L3800 with a curl cylinder directly pinned to the bucket. And IIRC, it uses a cylinder with a ~20" stroke.
IF, I added a cylinder of 24" stroke, I would gain curl angle/ range of travel, BUT, would get to the point where the cylinder rod hits the loader arm, so its not possible.
IF, I added a 4-bar linkage like used on loaders, I would gain nothing in range of travel.
BUT, using the 4-bar keeps the cylinder rod away from the loader arm and allows for the use of a longer cylinder.
Bolt cutters are a totally different thing...
And lets keep it civil. No need for the digs and insults.:thumbdown:
Edit: Sorry, I didn't see page 2 where self-leveling was discussed further. With that said, I remember experimenting back in the '70's with development of a self leveling loader using a flow divider valve to level the bucket as the loader was being raised. The project was less than successful.