Self-Leveling - basic question

[rbargeron]

Given the apparent pain level associated with Kubota's hydrailic self-leveling FEL, I was wondering why a mechanical linkage (like many other machines have) is not used. What are weaknesses of the multi-link setups ? Something like the system on JCB loaders seems simple and reliable - but I guess it would mean a redesign of the basic "look" of the loader.

 

[beenthere]

I understand the problem to be the extra weight the additional structure would add to the loader, subtracting from the capacity of the loader. I suspect the structure would have to be pretty substantial to take the loads and add to the ballast needed to hold the rear end down. Maybe someone else has a better answer.

 

[rbargeron]

The B21 and L35 both have a leveling feature - I haven't seen one up close - can anybody post a picture? Or describe it? Thanks

 

[TWINKLE_TOES]

Dick,

A couple of rods run up the right loader arm. A bell crank @ the loader end is driven by the bucket movement. This forces the rods to move back and forth. At the loader joy stick, one rod enters the control valve to move the spindle to effect the bucket curl/dump circuit. Sorry, no camera no scanner... no picture, but I do have a tractor/w3tcompact/icons/smile.gif Hope this helps.
Al

 

[Charliebrn]

OK, so why does this arrangement add so much weight? It doesn't sound like it should. Maybe I'm missing something?

 

[MarkV]

Dick, I don’t see where weight would be the issue. It is just a guess, but I wonder if the capacity of the loader made the engineers feel a mechanical linkage would not be smooth enough for the loads the L48 can lift. Of course it doesn’t sound like the hydraulic system they came up with is quit right either.

MarkV

 

[rbargeron]

Thanks Al - given a choice between a tractor and a digital toybox, I'll choose the tractor anytime.

So the B21/L35 self-level system is actually hydraulic with mechanical feedback to the valve.

I still like the all-mechanical 4-bar linkage that JCB and others use. Doesn't seem like it should reduce loader capacity. Some pretty big machines have it.

Dick Bargeron ------- L5450 - Power is good, so is weight.

 

[MChalkley]

Dick - I agree. I don't have much experience with self-leveling loaders, since the EarthForce is my first, but I can't see how you can get any simpler, stronger, or more effective system than the mechanical linkage.

 

[rbargeron]

Mark - got any pics of your EF or some links ?

 

[MarkV]

Dick, Like Al, I have a B21 with the mechanical feedback which actuates the self-leveling feature. It works pretty well for me and has for the last 750 hrs of use. You lost me when you refereed to a “digital toybox”. I normally think of digital referring to an electronically activated system and I am not aware of that being used on any of the TLB’s.

MarkC, knowing that you are not digitally photo challenged, like myself, I would also be interested in see how the self leveling system works on the EF.

MarkV

 

[MChalkley]

rbargeron - There's a bunch of them in the "Goodbye Kubota, Hello EarthForce" thread in "Other Brands". If you go to <A target="_blank" HREF=http://www.tractorbynet.com/cgi-bin/compact/showflat.pl?Cat=&Board=other&Number=72595&page=0&view=collapsed&sb=5&o=7&fpart=7&vc=1>this link</A>, about 3/4 way down, you'll see the first one. Then, spread over the next few pages, you'll find another couple dozen pictures.

 

[MChalkley]

MarkV - Here's two pictures that may help for now, but I'll try to get a couple more that better illustrate what happens.

The first one . Notice the pivoting arm that the rollback/dump cylinders are attached to. It pivots on the pin in the loader arm itself. Next, note that it's attached at the other end to the tractor just below where the loader arm itself attaches, by means of a fixed length tube. As the loader arms go up and down, the pivoting arm moves with the loader arms. It's set to just the right length, so the movement of the pivoting arm moves the attachment point of the rollback/dump cylinder just enough to correspond with the change in bucket angle that you need to keep it constant. It doesn't make much sense the way I said it, but if you compare that picture with <A target="_blank" HREF=http://www.tractorbynet.com/forumfiles/19-93412-PC220026b.jpg>this one, you'll get a better idea of what's going on. Note carefully how the angle of the pivoting arm changes with respect to the loader arm as you go from fully raised to fully lowered. Since the rollback/dump cylinders are anchored to the pivoting arm, the angle of the bucket is changed when they move. Does this help explain it at all, or should I try again?

 

[MarkV]

Got it Mark. Thanks for the details.

MarkV

 

[rbargeron]

Like I said to Rat - I've not been keeping up. But I just went through the EF-5 story - Great ! Certainly removes any doubt about your TW (tractor whacko) status ! Of course that became clear about the time the Michelins went on the L4310. Any pictures of the EF-5 with dirt on it yet?

Dick

 

[MChalkley]

Dick - Oh yeah, no doubt about it - my tractor whacko status hasn't been in any danger for some time now...

As for dirt, not much in the pictures, but if you look at the second one in my post to MarkV above, you can see that I dug holes with the rear tires pushing a gravel pile around... Ok, so it's not much - I'll work on getting some dirtier pictures, just for you.