I'll try to explain the circuits and how I plan to power them a little better.
The small knuckle boom I plan on using is actually a a620 backhoe attachment off a ditchwitch trencher. I will be making several modifications to the backhoe attachment to convert it to a knuckle boom loader, but the basic functions will remain the same. When I got the attachment, I also got the pump and all valves. I intend to mount the pump to the front of my drive motor just as it was originally mounted to the Ditchwitch. The control valve is PB. From this valve I intend to plumb another valve bank to power the conveyors, the log clamp and log deck drive. It is unlikely that I will be using the knuckle boom at the same time I am sawing and splitting. This seems like the easiest method to accomplish those tasks and also makes jumping from high flows, like the saw and splitter circuits, if I was to tap into those hydraulic systems.
For the saw, I have a rexroth solenoid valve with built in relief,(rated for 30gpm),to supply oil to the saw motor. Valve will be activated by use of a micro switch mounted on the saw cylinder control valve. This way the saw will only run when the saw is being lowered into the wood. As soon as the saw cylinder valve is released, the saw should stop. I havent decided where I will get the oil for the saw cylinder, I had considered drawing off the saw motor, but the cylinder only needs a couple of gal of flow and around 100psi to do what it needs to do. Dropping 25gpm down to 2 gpm with a flow control is doable, but flow controls only work in one direction and I feel when I try to raise the saw bar, it would jump up faster than I can control it= damage. I also considered using a divider valve to control oil flow to saw bar, but I would still need a flow control and a pressure reducing valve to make it work. My best (cheapest) bet would be to also use oil from the knuckle boom pump since it is a sectional pump with only about 4gpm on one section. I am also aware that there is a proportioning valve designed to do exactly what i am wanting to do, but the price is pretty high,(I got a quote of around $600) and they require constant tinkering with to keep in adjustment.
The splitter is pretty straight forward, need a valve capable of of 40gpm, PB would be nice in case i wanted to add something else to the system.
There is also the issue of the adjustable splitting wedge cylinder. This is another low flow circuit that doesnt require continuous oil flow or high pressure and can be ran off the smaller knuckleboom pump. About the only thing that would need continuous oil flow would be the off bearing conveyor and a simple selector valve will do. There is also the issue of the outrigger cylinders (4) to level and stabilize the machine when using the knuckleboom. I could pull oil from any circuit for this operation since the outriggers would be lowered before any other action would take place and only be raised after the other actions are complete.
