Regenerative Log-splitter Bi-Directional Circuit

N8ghz · Oct 12, 2011

Here is a circuit diagram of a circuit I intend to experiment with. This diagram is showing the circuit with the main valve centered, and the regen valve de-energized....with oil going to Tank as it would normally. The gauge on the P line is showing 0 PSI or a no restriction circulitory P to T flow. When the main valve is shifted to split, the machine would run the way it does before adding the regen valve and the (2) Tees with check valve. My main valve is a manual lever-type with detent pop-off on return, (not the solenoid type shown). I intend to use a solenoid N.O. valve for the added valve and add a tab on my main valve handle to add a N.O. momentary push-button that I can push as desired, with my thumb, to energize that valve,which will block the oil to the Tank and send it to the P thru the check valve, thus allowing regen to occur. This should allow me to rapidly extend and then release the button when nearing the log. It should also allow me to rapidly Retract (which will be faster than the regen Extend) and release the button wherever needed to set up for next split. I see no problem putting it into detent, pressing my button, and releasing the button just before it fully retracts, so as to have enough pressure to pop to neutral as it normally would do without the regen circuit.....and that is only IF I needed to fully retract which with similar length logs would not be an issue.

BTW, the 1000 PSI relief will be 1500 and the GPM will be lower than 10 for my test (tractor just above idle). This on a 3-point splitter with a 4"x24" cylinder with a 2" rod.

I am not mentioning hose/fitting sizes, as I do intend to move to 3/4", but am going to try it using 1/2" to see what it looks like in operation.

What do you think?

Here is the drawing:

J_J · Oct 12, 2011

The regen pressure on the retract might not be enough to operate the detent kick off to neutral.

Some are adjustable.

N8ghz · Oct 12, 2011

Yes, that is what I think too. However, with logs shorter than requiring full stroke, I should not have a problem, as I would stop before it ever went all the way back. Of course, if you wanted to do that, you could put it in retract and walk away. The regen button would be N.O, and thus no regen.

J_J · Oct 12, 2011

I have seen kick back to neutral as low as 600 psi.

Cyl regen.

http://www.hwhcorp.com/ml37939.pdf

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oldnslo · Oct 12, 2011

As an option I believe sun hydraulics makes a mechanical regen system that operates on pressure so no electrical switch is required. Not sure about the cost though.

SPYDERLK · Oct 12, 2011

How can regen work on retract? Pressure on the piston side must always be lower for it to retract. If it is even near the same on both sides it will extend because the pisto side has greater area. I think regen will cause extension even if you have the main valve calling for retract.
larry

N8ghz · Oct 12, 2011

That is a good question. I am hoping the check valve will take care of that, we shall see.

The more I think about it, I don't believe it will work retracting.

oldnslo · Oct 12, 2011

N8ghz said:
That is a good question. I am hoping the check valve will take care of that, we shall see.

The more I think about it, I don't believe it will work retracting.

It will not work on retract.

Not to rain on your parade but with a cylinder ratio of 1.33:1 it will be difficult to make regen work on extend also. Regen works best when cylinder ratio's are 1.8:1 or higher. I would suggest retracting the cylinder and then tie both cylinder ports common and install a gauge, then try to extend like regen mode just to see if it will work. Look at what your pressure does while in regen mode.

Reason being is that you only have 3.14 sq inches of area to extend the cylinder. Any back pressure from line losses, pressure drop through valves, fittings, etc. add up to make the whole system work real hard and do no work.

The reason regen works on the tilt cylinders of FEL's is the over hanging load helps extend the cylinder.

Roy

kennyd · Oct 13, 2011

oldnslo said:
The reason regen works on the tilt cylinders of FEL's is the over hanging load helps extend the cylinder.

Roy

I agree 100% Roy.
I have been thinking about this since he posted it-but could not wrap my head around how it could work. I know in cases like when a cylinder is used for chute rotation on a snowblower the regen will just cause the cylinder to lock-up since there is no weight "pulling" on the cylinder.