Dynamic Rear Weight

[npalen]

Great feedback guys! Much appreciated.

 

[schmism]

with a hydraulic toplink you could do it (purple bar).

something like this.

remember stroke lenght of the top link to rotation of the counter weight is relative to the distance between the 3pt pins and were you attach the top link on the green "bar" BELOW the pivot point.

It would seem that some follow up math to show how much weight you could "gain" by doing that is in order also as many people dont think it accounts to much (but it does)

 

[xtn]

It's doable without a top link at all.

The weight would be designed to mount where the top link mounts to the tractor, and to pivot up and down around that mount just as a top link would. Most of the mass would be concentrated at the other end. Along the lower side of the weight would be a slot running fore/aft. Through this slot would be a bar attached to the lower lift arms. If you get the geometry right, lifting the 3pt would tilt the weight up and rearward.

 

[schmism]

It's doable without a top link at all.

The weight would be designed to mount where the top link mounts to the tractor, and to pivot up and down around that mount just as a top link would.

THat was my inital thought also, simular to a PHD... but the problem you run into is insufficient height in the lower position, and if you rigged it were you had enough height, you wouldn't gain that much rearward travel as you brought the 3pt arms up.

But at some point you have to wonder about the complexity involved to achieve what stacking a few more chin weights on the rear of a standard ballest box does.

 

[JoeL4330]

with a hydraulic toplink you could do it (purple bar).

something like this.

remember stroke lenght of the top link to rotation of the counter weight is relative to the distance between the 3pt pins and were you attach the top link on the green "bar" BELOW the pivot point.

It would seem that some follow up math to show how much weight you could "gain" by doing that is in order also as many people dont think it accounts to much (but it does)

As the diagram shows, this would be a good way to raise your center of gravity ...and compromise your lateral stability ...but, why?

And, the only time I can think of when I suddenly needed more weight further back was when I was finish-mowing down a steep slope in 2WD (a no-no, don't try this at home) and when the rear wheels "unweighted" I had no engine braking and no brakes ...so, my "dynamic" solution was to raise (raise) the mower...it had been running on its wheels, contributing nada to rear weight; when raised, it "dynamically" put enough weight on the rears so I could stop gracefully ...and put 'er in 4WD.

If I actually wanted to design something to accomplish this, I would mount a boom pole on 3ph with max weight at end and a (castored) tail-wheel. Normal running, let it float and run on tail-wheel ...to super-weight the rear, raise the 3ph just enough to come off the tail wheel (and/or, hydraulically retract the tail wheel)...as long as the weight didn't raise above my over-all CG, I wouldn't be subject to an undesirable change in CG, which is what the diagram depicts ...or, perhaps I don't understand the issue.

Of course, this approach seriously compromises your turning radius. It may occur to you that this design solution will work in opposite fashion if the 3ph has no upward float (i.e., has down pressure) or if the boom-weight is attached to a sub-frame, and we've just invented a long "wheelie-bar"

 

[npalen]

http://www.laforge.fr/photosnews/challenger-sur-tracteur.jpg
Looks like this arrangement would sure provide some "weight leveraging".

http://www.laforge.fr/photosnews/challenger-sur-support-grand.jpg
This is the mounting arrangement for the weight most of which doesn't show up in the first photo above.

LAFORGE - News and innovations
Laforge has some cool looking stuff if you scroll down the page.

LAFORGE - Fleximass
Some more dynamic weighting system.