Subject:
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Re: Road grader
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Newsgroups:
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lugnet.technic
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Date:
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Tue, 4 Oct 2005 00:27:18 GMT
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Reply-To:
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Geoffrey Hyde <gdothyde@bigponddotnetdotauSAYNOTOSPAM>
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Viewed:
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5552 times
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"Bubba Brant" <bbrant@anchorsign.com> wrote in message
news:InsL4L.1BMs@lugnet.com...
> In lugnet.technic, Nathan Bell wrote:
> > Why do the front tires of Road graders tilt sideways? My guess is that
> > 1)it
> > might lower the blade, it won't lower that much 2) to be able to drive on
> > a
> > tilted surface. If the first is true, it would not lower the blade much
> > unless
> > they tilt more than 45 degrees. If the second is true, then do the 4
> > rear
> > wheels have a way to tilt sideways, or does the whole frame glide forward
> > at a
> > twisted angle?? I should post some new pics in the next few days of what
> > I have
> > built so far along with some updated pics of my new crane design.
I've seen quite a few graders in my time, and they are an amazing piece of
earthmoving machinery to watch in action.
> I called my brother in law who owns a large utility company, which has
> about 4
> of the Cat 14H Motor Graders, and he said that the front tires tilt for
> two
> reasons.
>
> The first is when you are going in forward, it gives you a better turning
> radius, this is vital because the machine is so long.
This is particularly true when you have an articulated motor grader with
hydraulic steering. Basically, what the machine operator does is send the
tilt of the tires to the left, and the articulated portion of the grader,
usually located just beneath the cab, where the engine frame meets the arch
that supports the main blade, to the right (or vice-versa) and then they can
turn around in the size of a two way street intersection with some models.
It is quite amazing to watch a grader do almost 360 degrees of turn in such
a small space!
> Secondly, he said that when the machine is grading in reverse, the tilt of
> the
> tires gives them better traction, therfore making it easier for the
> machine to
> grade backwards without slipping from left to right because the force of
> the
> dirt on the back side of the blade causes an "upheval" action on the
> entire
> machine.
I've never heard of graders grading backwards, but I do know that when
grading they can set the blade offset to the left or right on the machine,
they can even set it right over to one side or the other when they want to
do an almost-vertical cut, and scrape the sides of a cut through a hill and
make it neat and tidy.
Some graders also can offset the drill of the blade using the steering and
the tires to position the tires to one side of the grader, this is most
effective when they have to move large amounts of earth aside and then
redrill it back, such as when profiling a road that is later to be sealed.
Tires that can tilt are most effective in this situation, as the operator
simply positions the tires to ride on the tilted ridge, and the grader
engine behind helps the blade push the dirt into the desired spot most
effectively.
> He said that the rear tires do not tilt at all, nor does the machine
> "twist"
> because both tires must be tilted the same way, therefore the machine gets
> slighty lower in the front, but stays on the same plane.
The only tilt the rear tires have is in some models where they have tilting
drive assemblies that are aligned with their direction of travel, I expect
this is so that they can more easily drive through areas that have holes or
drains in them. This is quite effective when used to rip up a road that has
a lot of holes in it.
They don't have rear steering tilt, although as I described above, some
larger grader models have an articulated cab, which can make for quite a
tight turning radius.
--
Cheers ...
Geoffrey Hyde
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Message is in Reply To:
 | | Re: Road grader
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| (...) Nathan, I called my brother in law who owns a large utility company, which has about 4 of the Cat 14H Motor Graders, and he said that the front tires tilt for two reasons. The first is when you are going in forward, it gives you a better (...) (19 years ago, 3-Oct-05, to lugnet.technic)
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