Innovative Concrete Cutting Saw Delivers Productivity Using Power-Dense Hydraulics
“I hate to admit it, but we used some competitive products on an earlier machine. That did not last too long though, because we ran into some serious availability issues. So we switched to Power Systems and Eaton and never looked back.”
Nomad Engineering owner
Modern concrete roadways are designed to crack at predetermined points, typically every 13 to 27 feet depending on state requirements. Under each of these “control joints” is an “expansion basket” consisting of many dowel bars that are around 20 inches long and are usually either stainless steel or regular steel coated with green epoxy.
To be certain the concrete cracks over the expansion basket, the slab is sawn to create a weak point. Because the slab is weakened at this point, it cracks all the way through, leaving the coated dowel bars suspended at the center point. They are coated so they don’t stick to the concrete and prevent the two separate sections of road from shifting up or down. As the road expands and contracts, the slabs can slide on these dowel bars and remain parallel to one another.
aControl joints are typically cut with riding concrete saws or walk behind self-propelled saws, which follow a chalk line on the pavement marking the location of the expansion basket. Currently, the procedure is to start the cut toward the middle of the slab and work out to the shoulder edge.bc
Then, because there is no shoulder at that point in the project, the operator of a walk-behind saw has to manually turn the saw around and re-position the blade in the cut before sawing to the other side of the slab. Sawing a straight line requires a great deal of operator skill.
Making the entire cut automatically in a single operation requires a machine able to position the saw head or heads, and supply enough power to both operate the saw blades and move the heads across the slab. This must be done in a very dusty environment under all weather conditions, and usually at night.
Offered by SpiderCut Systems, LLC of Burlington, Wisconsin, the SpiderCut Span Saw is an all-hydraulic vehicle equipped with Eaton pumps and motors to provide the power-dense hydraulic muscle to cut expansion joints in a single pass. The power to turn the blades on the saw’s two heads comes from a pair of Eaton Series 1 hydrostatic pumps rated at 4.6 in3/rev that deliver up to 40 gpm at 5,000 psi. There is a separate pump for each saw head. The piston-type motors are Eaton 74328 models that displace 3.0 in3/rev.
The carriage that moves the heads is powered by an Eaton 2600 Series gear pump and a low-speed Eaton motor. Two Eaton 70160 1.24 cubic inch hydrostatic pumps supply power individually to each drive wheel to propel the vehicle.
“I hate to admit it,” said Tony Mertes, owner of Nomad Engineering, which provided engineering design for the saw, “but we used some competitive products on an earlier machine. That did not last too long, though, because we ran into some serious availability issues. So, we switched to Power Systems, our Eaton distributor, and Eaton and never looked back.”
On top of that, Mertes said, “We like the fact that spare parts and experienced service people are available for the Eaton products we use anywhere in the world.”
While span saws have been used before, most are too large and difficult to set up to be cost-effective. The flexibility and quick set up that the SpiderCut Span Saw offers, plus the smooth flow of power and very high power density of the Eaton hydraulics, have made this a very popular choice among highway contractors.