This is a relatively old, but still serviceable John Deere farm tractor at the Warren, CT fall fair. Some young guys were demonstrating using it to power a hydraulic wood splitter.
Here’s the tractor connected to the wood splitter. Notice the two hydraulic lines running to the pump mounted on the tractor’s PTO.
This is a hydraulic pump mounted on the second transmission/power take off point of the tractor. For those who don’t know about these things, most larger tractors have a second transmission, powered by the same engine that powers the drive wheels that powers farm implements that are connected to the tractor.
In this case, the PTO is powering a pump for pumping hydraulic fluid through the log splitter so it’s cylinder can split wood.
Here’s the whole rig: tractor, PTO, pump, hydraulic lines, splitter with (yellow) cylinder and valve.
The valve has a handle on it so that when pulled in the direction of the tractor, the cylinder pushes the piston (and log) toward the splitter and splits the log. These systems can generate 20 or more tons of pressure which will generally split anything.
To return the piston into the cylinder, you push the lever back toward the splitter wheels and it retracts into the cylinder. The pump, which is always going, keeps pressure in the system.
The size of the cylinder, the size of the hydraulic fluid reservoir, the size of the hydraulic pump, and the tractor’s horsepower all together determine the power of a given log splitting system.