With a Sidegrader attachment on a mini-excavator, the contractor can rough-grade lots to within a few tenths and use Sidegrader to tighten up the rough pass in front of a small roller (about 3,500 pounds). Then Sidegrader does the finish pass, which is also compacted. The concrete contractor then sets forms directly on the completed grade.
Traditional methods for getting ready to pour sidewall — over-excavating, setting forms, backfilling, plate compacting — normally yield 800 to 1,000 feet of completed grade per day. The contractor who designed and builds Sidegraders says his attachment averages 1,800 to 2,000 feet per day. In many cases, it is possible for the attachment to complete a satisfactory grade in native material.
"We have been using the Sidegrader for about four years (grading more than 4 million linear feet), and the attachment regularly averages 1,800 feet per day," says Bill Culliton, of Sidewalk Grading Systems (SGS) in Eatonville, Wash.
After initial installation, Sidegrader can be removed from the excavator in 30 minutes. It can be re-installed in about the same amount of time.
The product attaches at a hinged connection point to one corner of the backfill blade on a mini-excavator. The hinge allows the attachment to be folded in front of the backfill blade for a narrow transport width. A strut reaches from the far end of the heavy-duty grading blade (about the size you'd expect to see behind a 90-horsepower farm tractor) to a bracket welded to the rear of the track frame.
A heavy-duty caster rides on the curb to provide a constant reference for the grade. As the excavator moves along the road, a Topcon System Five Slope Sensor transmits slope information to the control box managing the proportional valve. The hydraulic cylinder in the circuit adjusts the blade to the proper slope.
Driveway slopes are preset into the grade computer so the operator can punch a button and the control automatically adjusts the slope and depth for the driveway grade.
Culliton's application experience is limited to Komatsu's PC50 MR-2, an 11,000-pound machine, with steel tracks.
"Steel tracks with road liners are much more suited to the Sidegrader application than rubber tracks for two reasons," says Culliton. "1) With the road liner added to the steel track, there is much more stability because of the additional width; and 2) Wear — the road liners in our application will last much longer than rubber tracks. Ninety-nine percent of our tracking is on asphalt roadways."
Culliton says SGS buys excavators with long booms on them to speed the grading process. They use the excavator bucket to loosen hard material, remove rocks, and push out or pull in material in front of the blade as needed.
Sidegrader's $55,000 price tag can be shocking. But the price includes the Topcon grade-control system with a slope sensor, the control handle, quick-disconnect hydraulic connectors, unlimited training from SGS, extensions for grading sidewalks beyond a planter strip or boulevard, Smart Grade Stick with digital level, hand tools and a carrying bag.
"It is unusual for us to earn less than $2,500 per day in profit when using Sidegrader," says Culliton. "So working 22 days pretty much pays for the Sidegrader."
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