On Thu, 11 Nov 2010 23:56:27 GMT, (dan) wrote:

Anyone here know anything about running a road grader?
I was looking at a tractor forum where someone had made a pull behind
grader from an old snow plow blade.
http://www.tractorbynet.com/forums/b...nd-grader.html

And it got me thinking of how graders do their thing.
The key point is the blade is mounted between the front and rear
axles. That allows the blade to lift/dip half or less as much as the
axles as it rolls over high and low spots. This allows them to make a
flat surface quickly.

But then I started to think about crowning a dirt road. The blade is
lowered to dig in a little deeper on the ditch side, and angled to
move the dirt to the middle of the road. But then the rear wheels go
over the newly crowned part the whole grader leans over. This makes
the blade lean over too, cutting even more of a crown. Keep going
like this and you would roll the grader on it's side, it would seem.

Does the operator have to re-adjust the level of the blade after
starting the cut, making the blade parallel to the rear axles?
Is there some kind of automatic level thingy to keep the blade at the
same angle, or is that up to the operator?

I might like to copy the one I found on the tractor forum, but I would
like to add hydraulics to:
raise and lower the blade,
tilt the blade,
and maybe angle the blade.

I would probably use a 12v power pack with electric solenoid valves.
And then I got an idea. If I mounded some kind of pendulum on the
blade itself that would trip switches to activate the valves, it could
be made to maintain a preset angle, regardless of the angle of the
frame. I would have to add some kind of dampening of course, and the
precision wouldn't be too great.

What do you all think? I'm still in the "thinking about it" stage, so
no plans to start work on this for some time, but the more I design it
in my head, the less problems I'm likely to run into later.
I can barely remember my uncle being the grader operator and having a
large steel wheel at each side to raise or lower the blade which was
mounted on a turntable to adjust the angle to the direction of travel.
This turntable was mounted to trailing arms from the front of the
machine, allowing it to be raised or lowered. The blade could be
tilted and slid out to one side or other. The whole apparatus was
towed behind a truck or tractor.
Latter, these were replaced with self propelled, hydraulically
operated machines we see today.
Gerry :-)}
London, Canada