Owners of road construction and maintenance equipment from Wirtgen America Inc. benefit from decades of experience in engineering and design built into Wirtgen milling machines at Wirtgen GmbH in Germany.
What they may not realize is that they may benefit from products and engineering conceived and executed in the United States on German-sourced Wirtgen equipment for sale in North America. "At Wirtgen America we design options and kits for the local market that aren't necessarily suited for the European markets or for the rest of the world," said Scott Lyons, Engineering Manager, Wirtgen America Inc. "It's important for North American contractors to realize we have engineering capability here, and that we engineer and manufacture kits, options and hardware right here in the United States."

For example, the new rumble strip attachment for the W 600 DC is a home-grown product."We call it the W 600 DC Rumbler II," Lyons said. "We designed the Rumbler II attachment right here at Wirtgen America, to fit with the base tractor unit designed and built in Germany."

Lyons said the original Wirtgen America rumbling concept came from Wirtgen America President Stu Murray. "He decided after seeing the potential growth of rumble strips that Wirtgen America should sell a machine that could quickly grind them," Lyons said. "He collaborated with our fabricator, Fabriweld in Ohio, to design and build the first rumble attachments for the W 500, the W 500 Rumbler."The original Rumbler system system was then fitted to the W 600 DC. "The 500 Rumbler can go about 70 feet per minute, but the 600 Rumbler can go 80 to 90 fpm," Lyons said.

Customers requested higher productivity. "We developed the W 600 DC Rumbler II that would smooth the ride for the machine and driver, and would put rumble strips in faster," Lyons said. "The economics indicate that the faster an operator can go, the more profitable it is for the owner, and the 600 Rumbler II can go up to 180 fpm."

The cutter drum for the Rumble II also was designed at Wirtgen America, and fabricated in Ohio. "We use Wirtgen holders and recommend using Rhino bits to conserve the holders and make the drum last longer," Lyons said.

Urgent Need For Rumble Strips
The W 600 Rumbler II -- and its predecessor, the W 500 Rumbler I -- are responses by Wirtgen America to the urgent need in the United States to mill rumble strips into highway shoulders both quickly and economically.

For years, rumble strips on shoulders have been recognized by the Federal Highway Administration (FHWA) and many state departments of transportation as being able to dramatically reduce accidents and fatalities due to run-off-road incidents.

Rumble strips may be formed in fresh asphalt shoulders when they are placed. But in a December Technical Advisory, the FHWA unequivocally stated that milled-in strips are preferred for saving lives, due to their ease of placement in existing shoulders and higher degree of vibration (see related sidebar).
The engineering behind the Rumble II serves this need nicely.

"We have a six-sided hydraulically driven wheel attached to the front side of the W 600 cutter housing," Lyons said. "That causes the subframe, or the cutter housing itself, to move up and down, to create the rumble strip pattern in the shoulder." Thus Wirtgen America's new design leaves the machine frame stationary.

The standard cutter drum housing on Wirtgen utility class machines is on the right hand rear corner of the machine. "We take the side skirts off the housing, remove the cutter drum, take the conveyor and rear moldboard off the back of the housing, and bolt a stub shaft onto the end of the gear box," Lyons said.

"Then we put a side plate on the side of the housing with a bearing that supports the stub shaft," he added. "And we put a large pulley on the end of the stub shaft with a belt to the drum shaft; it drives the rumble or texturizer drum."

Providing Texturizing Capability
The Wirtgen America Rumbler II design provides an extra-wide attachment housing which permits moving the Rumble drum from left to right so strips can be cut on either side. And this width opened up yet another opportunity.

"Because of the 6-foot wide housing, we figured we could put a fine-toothed texturizing drum in the housing for doing bump removal and texturing of asphalt or concrete pavements," Lyons said. "It fits within the standard Rumble II subframe. We simply remove the shaft and rumble drum, and install the new texturizing drum and shaft."

Wirtgen America expects that this capability will compete against complicated diamond grooving and grinding machines."We certainly hope to make that a reality," Lyons said. "Precision can be attained by a 20-foot grade averaging ski on each side of the machine. And we also will use our grade controls with sonic tracer which reads off the grade averaging ski. We will be able to remove bumps and provide a surface that will be appreciably smoother for the driving public."

Development Phase Over
Last year constituted a development phase for the Rumbler II. "We were able to do some field testing with some of our cooperative customers," Lyons said. "We worked out a few wrinkles so that by the end of 2001, we had the attachment really 'dialed-in' and got a lot of good feedback with the way it's working."
The Rumbler II generated a lot of buzz at the Wirtgen Group stand at Conexpo/ConAgg '02. "We were getting a lot of interest in the Rumble II attachment," Lyons said. "It's evident that contractors are aware that the specs are calling for a lot more rumble strips around the United States, because everyone looking at the W 600 DC machines was also interested in the attachment. As a result of the show we sold seven units in North America and one to China."

Recessed Reflective Pavement Markers
Yet another locally designed adaptation for a Wirtgen machine was an application involving recessed lane markers and a W 350 in California. "The contractor had to cut grooves in the road at certain distances from one another," Lyons said.

"We came up with a system to meter how fast the machine dropped down and came back up," he said. "We also put on a skip-line timer so the machine will automatically know when to lower itself, cut the groove, and come back up over and over again."

That way the operator can move along with the W 350 milling machine without concentrating on the repetition of the actual cut. "They've been able to improve the production dramatically by using the machine adaptation which automates the cutting process for the operator," he said.

Also, the Combo-Cutter system on Wirtgen cold milling equipment is a long time United States-designed adaptation. And Wirtgen America engineers designed an early high-volume water pump for the WR 2500 stabilizer for use in arid regions. "Originally Wirtgen did not produce a high-volume water system for doing stabilization 20 inches deep, and adding lime or cement or water," Lyons said. "We added a high-volume water pump and automated system in which the controller would monitor how fast the machine was moving, and control the speed of the water pump to add just the right amount of water for the speed of the machine."

Thus, as the machine would slow down, the water volume would slow with it, and vice versa "Subsequently Wirtgen GmbH developed a high-volume water system for the WR 2500," Lyons said, "but we filled the gap for a couple of years until they did."

Rhino After-Market Parts
In addition, Rhino after-market wear parts are designed by Wirtgen America in Nashville for use with other brands of milling machines.

"We sell aftermarket wear parts for competitive milling equipment," Lyons said. "We sell cutter bits for all makes of milling machines. We sell cutter drums for competitive equipment. And there is a lot of interest in our Type III bolt-in holder system. We sell Type III bolt-in cutter drums for all machines, so there is great interest there. We also sell heavy-duty conveyor belts, urethane track pads and track groups for competitive units."

Development of most of these new products is customer-driven, Lyons said. "I generally don't come up with the ideas for new products," he said. "The market does that. Our salespeople speak with customers, who ask for special adaptations, kits and options. The customer speaks, and we serve them by coming up with a functional, consistent, efficient way of solving their problem."

And at Wirtgen America, solving these local needs through local design is a team process. "It takes a lot of people," Lyons said. "It takes me, our salespeople, our purchasing people, our fabricator, the whole organization to bring a product together, test it, put in production and out to the market."

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