Posted by Clint Dixon on Saturday, March 17, 2007 at 09:40:44 :
In Reply to: Paging Clint Dixon posted by Brent In Utah on Friday, March 16, 2007 at 20:56:03 :
Sounds great! Can't wait to see more pictures!
Actually the sales literature says that the PTO operates at 61-1/2% of engine speed when rotating in the direction of engine rotation. 47-1/2% of engine speed when rotating in the opposite direction. I have never actually counted teeth or did the math while having everything apart, but from experience, I can tell you the published figures sound about right. When I have used the PTO driven pulley drive at higher RPMs, there is definitely a noticeable difference in speed depending upon which way the PTO is rotating. Transmission and transfer case gear selection will have no influence over the PTO speed. So, it sounds like in order to turn the brush hog at 580 RPM, the truck’s engine will need to be turning either at 943 RPM or 1221 RPM. Quite a difference between the two.
I went and dug out my overrunning clutch that I used when I pulled a trail-behind Brillion field mower. It is setup for a PTO line that rotates the opposite direction of engine rotation. That was what the Brillion mower required. This would be the standard rotation direction of Tractor PTOs, which normally can not be reversed. So, it looks like things are looking to be in your favor assuming that is the direction the brush hog will need to be driven. With a brush hog, you probably will not have any choice in which way to turn the PTO. Unless, the cutting blades are flat rather than Z bent. Then you maybe could be able to mount them upside down and rotate them the opposite direction?
One word of warning: Use an overrunning clutch. It will attach to the Power-Wagons splined tailshaft. The PTO driveline to the brush hog will then attach to the splined male end of the overrunning clutch. The brush hog has a lot of rotational mass and acts as a giant flywheel. Without an overrunning clutch, you may just get going along real nicely with your first pass around a field, push in the clutch to slow down at the first corner you come to, and find that the flywheel effect of the mower will transfer torque right back through the PTO and driveline of the truck to push you right through the fence. Because of the clutch and PTO arrangement on the Power-Wagon, there is no way of disconnecting the mechanical link between the PTO shaft and the driveshaft to the truck’s rear axle short of throwing the PTO out of gear while in motion. Something one will probably not think of the first time it happens, while cranking the Armstrong power steering to full lock, standing on the clutch and brake pedals, biting off the end of your cigar, and watching the barbed wire roll up over the hood of the truck – all at the same time.
Junior
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