3 Point Geometry

[rangerfredbob]

I just winged a 3 point pallet fork attachment last weekend, worked with what I had and went for it... bought some forks with a frame that was on a skid steer in the past so it was set up wrong but for $20 I couldn't go wrong... it sat around for a couple years until I needed to move a pallet out of my driveway so I just did it...

I set the lower links so they were about 1/2" above where the arms are when bottomed out to give me max lift, and put the top link mount about 2" above the top of the frame which was about 16" above the lower pins which inconveniently is the same as the upper pin for my top link on the tractor side. By rough mental calculations I "thought" it might work out but was wrong... my 3 point arms lift about 1', so the base of the forks lifted that high but the tips of the forks only lifted about 6"... My shortest top link was bottomed out when I hooked it up and would have needed to be shorter to go in the lower hole on the tractor end so I'll use a chain for that in the future, should work.

Anywho, just frustrating that that geometry doesn't work out how you want at times... From what I'm read I'm far from the first to have this issue

 

[Wyobuckaroo]

Would not mind seeing a couple pictures of your set up. On the tractor if possible.

I also am having a hard time getting a set of 3pt pallet forks to this area as shipping cost and shipping connections are a bugger.

I may have to resort to homemade..

 

[SmallChange]

It'd be nice to have the height of the top link attachment point on the tractor infinitely adjustable, some kind of sliding joint with a screw to adjust it. Since there's not so much vertical force on this point it shouldn't be that hard.

 

[TractorGuy]

Does your tractor have multiple choices for top link connection? If so the top hole will have the greatest lifting force with the least amount of travel. The lowest hole will have the least amount of lifting force with the greatest amount of travel.

Also the CAT 1 standard for top link height from the lower links is 18".

 

[RalphVa]

I had a problem with the 3ph on the 4010. JD dealership had put the lift pins in the wrong location. Did not lift the bush hog very high: higher at back of tractor than at rear of the "hog". Repositioned the lift arms to the other location. Fine.

Never want it set up so that the top link is longer than the bottom lift arms. Geometry will then force the back end of what you're lifting lower than where it is lifted in the front.

Ralph

 

[Gordon Gould]

If you want to keep your forks level as they raise and lower you need your top link parallel to the lower lift arms. Set up the parallel geometry and then adjust the top link length to level the forks. Now the will stay level as you raise and lower. If the top link slants upwards compared to the link arms the forks will roll back as they are raised so the tips go higher than the back.

gg

 

[ruffdog]

The problem with figuring the geometry of the 3pt is the top link is always shorter than the lift arms. It is then hard to visualize what the implement will do as the upper/lower links swing through their arcs. I think the OP would achieve more what he wants if he gets the pin to pin measurement 18-20".

 

[Gordon Gould]

The problem with figuring the geometry of the 3pt is the top link is always shorter than the lift arms. It is then hard to visualize what the implement will do as the upper/lower links swing through their arcs. I think the OP would achieve more what he wants if he gets the pin to pin measurement 18-20".

On both my Kubotas the hinge points for the lower link arms and the top link are in a vertical plane and all my implements are also set up with the top link and lift arm connections in a vertical plane. So for that case the geometry I described works. I was not aware that other tractors and implements could be different. Don't know why they would be but there are lots of strange stuff in this world. Sorry if I caused any confusion if your tractor is different.

gg

 

[ruffdog]

Most tractors have the connection point for the lower arms under the rear axle and the top link is at the rear of the transaxle housing which makes the top link shorter.

 

[rangerfredbob]

This was more of a vent on how it ended up, as I should have measured one of the like 6 implements I have... But I do appreciate input as it will sure come in handy for future builds or when I get to reworking this thing...

Here's some pictures, looking at it now it's obvious the geometry is bad but I didn't build it on the tractor so I could see the top link angle... I'm pretty sure a short chain in place of the top link into the lower hole should at least lift level. I've used chain for a top link on my brothers pallet forks and it worked well, lets the tips of the forks float into the pallet, and with a chain hook on the end is very adjustable but that was more usable with the long links on a Ford 4000 tractor that lift like 2' instead of 1'

And other notes, I know there's some bad practices involved on that thing... I welded the lower link brackets right to the forks with no preheating... with the compressive force of lifting and the lifting force I figured the safety factor should be fine on this little tractor, plus it's only lifting like a foot...

On this tractor the top link point is about 3" back from the front pins for the bottom links