Im more interested in the 'suspension", that allows the
cutters to grind the high spots, without grinding a low when
the wheel(s) drop into a hole.

thanks

gary

wrote:
Im more interested in the 'suspension", that allows the
cutters to grind the high spots, without grinding a low when
the wheel(s) drop into a hole.

thanks

gary


All the road grinders I've ever seen have had a 5-6' track at about 3
places under them, 1 fore 2 aft. That would act like a long shoe on a
woodworking plane to smooth out any lumps and bridge any holes.

On Mon, 14 Sep 2009 17:23:53 -0400, Stuart Wheaton
wrote:

wrote:
Im more interested in the 'suspension", that allows the
cutters to grind the high spots, without grinding a low when
the wheel(s) drop into a hole.

thanks

gary


All the road grinders I've ever seen have had a 5-6' track at about 3
places under them, 1 fore 2 aft. That would act like a long shoe on a
woodworking plane to smooth out any lumps and bridge any holes.
Don't know about grinding machines but a lot of pavers used to use a
long, multi section ski to average out the surface - not so critical
on urban roads but critical on airport runways.
Gerry :-)}
London, Canada

dan wrote:
What's that Lassie? You say that fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Mon, 14 Sep 2009 13:55:10 -0600:

Im more interested in the 'suspension", that allows the
cutters to grind the high spots, without grinding a low when
the wheel(s) drop into a hole.

Same as a road grader. Support for and aft on wheels or tracks, and
cutter head in between. Bumps and dips are reduced by half due to the
position of the support relative to the cutting area.

Think of a flat road with a speed bump on it. As the grinder
approaches and the front wheels rides up on the bump the whole machine
tilts back. The rear wheels stay on the flat part of the road.
The cutter is lifted up, but not as much as the front wheels, leaving
a high spot. As the machine continues, the cutter head grinds down
the bump. Then the rear wheels encounter the high spot that the
cutter left, and the whole machine tilts forward as the rear wheels go
over the high spot. This lifts the cutter head again, but to a much
smaller degree.
Further passes continue to reduce the high spots.

Problems can occur if the bumps are at the same spacing as the
wheelbase of the machine.
It helps to have the cutter head closer to the rear wheels.


Most of the newer computerized ones go one better. They use a tracking
system that measures the humps and bumps and tells the computer where
they are. The computer then adjusts the cutter to suit. Most of the
newer rigs use sonar/laser sensors to track the road profile.

You can see the earlier version of this on the skid style paver machines.

--
Steve W.