Rockshaft ?

[miketrock]

How does a rockshaft work ? hydraulic or mechanical (gears) ? The shaft is in the back of the rear axle or transmission and lifts the 3 point hitch.

 

[GeoHorn]

A “rockshaft” is nothing more than a bellcrank.... but instead of the rod linear movement causing the shaft to rotate.... some power-source (in this case, hydraulic pressure on a piston) ... causes the shaft to rotate thereby moving the rod in linear motion. (Hyd pressure rotates the shaft and the attached rod moves the 3-pt hitch.)

Another form of rockshaft is a cam. Rotation of the shaft presents a raised lobe that transfers mechanical motion linearly. The major difference being that a cam rotates completely/more than 180-degrees, while a rockshaft only “rocks” a portion of an arc.

 

[North Idaho Wolfman]

Also note:
It's only semi coupled setup, thus you can pick up on the three point arms and pull the rod that connect to the cam on the rockshaft out and off of the bottom of the piston (not completely), this allows the three point to float.
There is no down pressure on the three point arms.

 

[miketrock]

Ok, thanks, hydraulic, i had no idea.

 

[troverman]

Apparently even three point hitches with dual hydraulic cylinders providing the "lift" also do not provide down pressure. Down pressure could be useful for certain applications.