Modifying 3PH To Allow Tilt AND Down Pressure?

[npalen]

http://www.tractorbynet.com/forums/hydraulics/122507-3ph-top-tilt-setup-use-2.html

Seeing the pictures in post #13 of this thread showing a cylinder on each of the 3PT side links: Makes me wonder if hydraulic down pressure can be used by raising the position control lever all the way to the top and then operating the cylinders? I assume this setup has a seperate valve for each of the two cylinders. (I do realize that down pressure is considered to be useless by many forum members.)

And then it raises the question (in my hydraulic mind at least) whether it would be possible to use a master and slave setup where the two cylinders are synchronized. And then the question is whether two cylinders could be brought "out of phase" to act like a tilt setup and then remain in that tilt while being cycled up and down. Would take some special valving I would guess.

For those unfamiliar with a master/slave hydraulic setup--the fluid exiting the rod end of the master cylinder is used to power the base end of slave cylinder thus keeping the two cylinders in unison. The bore diameter of the slave cylinder is usually about 1/4" less than the bore of the master cylinder to compensate for the area displaced by the rod of the master cylinder.

 

[boggen]

sounds like you will be shifting a lot of weight / force to the front wheels of the tractor. at same time reducing traction on the rear wheels.

i would be worried if the front axles and like could take the punishment, and if you end up more "stuck" due to not enough traction.

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i would say independent valve for each hyd side link. costs more most likely. but would allow you to clear the air out of each cylinder better. so there is no sponginess / bounce to the hyd cylinders, due to trapped air some place in a hose or hyd cylinder. along with so much easier adjustment of each cylinder. if you want them to move up and down then just grab both levers at same time.

would most likely suggest "float option" for each valve.

i might encourage some sort of "sub frame" much like a 3pt hitch backhoe with sub-frame would have, for more of a safety precaution of not splitting tractor in half. due to ya bouncing the tractor on 3pt hitch implement and front wheels. (rear wheels nearly or completely off ground)

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other option. making a full frame on rear end of tractor. that by-passes the lower lift arm lifting.

 

[npalen]

I had an Allis 720 with hydraulic down pressure. It was handy when just a little bit more "weight" was needed to get a blade to "bite" for example. Don't have to raise the rear wheels off the ground, just transfer a little weight and still have some traction left. It would be particularly useful on a front assist tractor where the front wheels can make up for any lost traction on the rear wheels.
I understand what you're saying about raising the rear wheels causing unusual stress on the tractor frame. It doesn't seem much different, however, than having a heavy attachment on the 3PH that is trying to raise the front wheels off the ground. That has to put a similar stress on the tractor frame especially when weight, such as an FEL, is trying to hold down the front of the tractor.
The valve for each cylinder as you suggest would give a lot of versatility . Might have to readjust the tilt occasionally.

 

[boggen]

*rubs chin* is there a way to put a "stay strap" some place for the 3ph upper main lift arm/s. so you did not have to raise 3pt hitch all the way up?

been trying to think back... at all the rear end of tractors. and not much there in way of a bracket / support frame you could run a chain or metal from. to hold things in place.

other words once you run 3ph all the way up. so you can use it as down force via side link hyd cylinders... you may run out of length via side link hyd cylinders to properly adjust the 3ph implement. if you could hold things not at max height / lift..... *shrugs*

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i could see some what of being a little bit of a *nag* needing to adjust one or both side link hyd cylinders more so if operating on a nice flat dirt road / gravel driveway that was nice and long and no curves. on other hand for me.... it would not matter. a few sections that are long. would be consider null and void. due to amount of curves, and needing to crown road this way or that way... way to much.

 

[MtnViewRanch]

Rob has had no problems with his setup that I know of and he uses his tractor pretty hard. I have no idea if it would be an internal problem for your tractor or not, but it is for some. Even if it is not an internal problem for your tractor right away. It is not built to take those upward stresses and for how long it is not a problem would be the question I would always be thinking about. Sort of, no question that there is going to be a problem, the real question is "when is there going to be a problem?"

Good luck, :thumbsup: not something that I would do with a typical 3pt hitch. :no:

Just my :2cents:

 

[npalen]

Yeah, I'm just thinking out loud here mostly and don't plan to try this anytime soon. We had an 8N Ford on the farm and then later an 801 Ford. To use the hydraulic cylinder lift on the trail type sickle bar mower, Dad tied a chain around the rear axle housing on one side looping around the upper 3PT lift arm. Hydraulic pressure for the single action cylinder on the mower became available when the chain tightened up. That was a crude way of doing it but got the job done.
I understand what you're saying, Brian, about "when is there going to be a problem". Better safe than sorry. As they say, "Don't try this at home".

 

[ishiboo]

I've thougth about this as well. The Kioti uses two external lift cylinders for the 3-point.

The problem though is synchronizing them the 99% of the time you don't want tilt, as well as making the float process work when you don't want down-pressure. I think overall, the much cheaper/easier route is an external tilt cylinder, and accepting the fact 99.99999% of us get by without down pressure.

 

[Agvg]

This is an solution to transfer weight from the tractor to the implements, works very well

VAMA Product - Road blades

 

[boggen]

This is an solution to transfer weight from the tractor to the implements, works very well

VAMA Product - Road blades

took me a while looking at photos and video in the link... it looks like that "foot" for lack of better term. connects to the swinging draw bar area of the tractor (draw bar that connects below the PTO shaft) and then uses a hydrualic cylinder to put a little pressure down on things.

pretty cool!

 

[Agvg]

Yes, its a simple construction seems to work very well for scraping ice of the road, here in Scandinavia a lot of the road maintenance is done by large tractors so there are much nice equipment to look at when travelling.