PTO Gearboxes
PTO or Increase gear boxes are mainly used on agricultural tractors where more hydraulic power is necessary than the system on the tractor can offer.
The quick release coupling on the gear box attaches to the tractor PTO shaft and steps up the PTO speed to one much more suited to the efficient speed of a hydraulic pump. A Gear pump is suited to the other side of the gear box.
The Power Take-Off, most commonly referred to by its acronym, PTO, is a common kind of mechanical power delivery in the mobile machine marketplace. The PTO is usually a method 
of transferring high power and torque from the engine (usually via the transmission) of trucks and tractors. In mixture with gearboxes and pump mounts, almost any type of mechanical power transmission is possible.
There are three common power take-away methods in the mobile machine market; tractor design, truck transmission design and engine crankshaft-driven, although the latter isn’t commonly known as a PTO. The crankshaft-driven method of power transmission is often utilized for hydraulic pumps installed to the front of an on-highway vehicle, such as a plow/spreader or cement mixer. A little shaft with U-joints attaches to a yoke coupler to turn the pump. This configuration of drive isn’t generally referred to as a PTO, however.
The tractor PTO goes back pretty much as far as tractors. Many early PTOs were driven from the transmission, which being proudly located at the back of the tractor, allows for easy location of an output shaft. The transmission kind of PTO is engaged when the transmission clutch is also engaged, and can be coupled directly to transmission, to ensure that when the clutch is usually depressed, the PTO isn’t driven.
If the transmission is driving the wheels, then the transmission PTO is turning. This does mean the apply can backward-power the tranny as well when the clutch is usually depressed, such as down a hill or if the attachment has a mechanism with high rotational inertia, resulting in surging of the drive tires. This was avoided by the addition of a dedicated overrunning clutch for the PTO, which prevents torque from becoming applied in the opposite direction.
A live PTO often uses a transmitting clutch with two phases. The initial stage of the clutch works the driven portion of the transmitting, and the next stage of the clutch controls the engagement of the PTO. This technique allows independent control of the tranny, to ensure that the PTO maintains procedure regardless of transmitting clutch activity, including stopping of the tractor itself. For a tractor with a mower attachment, for instance, this is the very least requirement; you can’t have the mower turn off when you feather the clutch up a hill and around a tree.
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