Stopped in Conway, Arkansas on the way to Fredericktown and found this Rockford PTO for the UC-60 Power Unit. With the clutch disengaged, the three piece drive gear plate (lower left..not installed) rotates freely between the two discs. When the lever and cutch is engaged, the back plate compresses onto the three piece plate/drive gear and picks up the power from the flywheel. You can see the ring gear on the UC-60 flywheel.
The yoke that fits around the two posts on the pressure plate was broken on the Rockford, but JP had a similar unit made by Dual Disc in Racine, WI. The yoke on that one was better made and fits the Rockford fine.