February 12, 2007 – Powerful and precise are two words that can be used to describe the latest addition to the line of slipform curb and gutter machines built by GOMACO Corporation of Ida Grove, Iowa. Engineered to fill a need for a machine with more capacity than the GOMACO GT-3200, while being more compact than the GT-3600, the all-new GT-3400 combines the best features of both in a package aimed at the heart of GOMACO™s fastest growing market segment.
Powered by a 127 hp (94.7 kW) Cat® 3054E diesel, the GT-3400 is a versatile machine that can slipform curb and gutter, sidewalks, and barriers and parapets up to 50 high when equipped with the appropriate molds and accessories. It™s mounted on three independently controllable crawler tracks and features GOMACO™s advanced G21 automated control system.
The Cat diesel is used primarily to power the GT-3400™s hydraulic systems, explained research and development project manager, Scott Pedersen. The machine has pumps for the trimmer, tracks, auger, lift cylinders, vibrators, and the cooling fan drive, and they™re all powered by the 3054E diesel. This arrangement gives us tremendous control over the various machine functions, and the result is a highly flexible and extremely precise piece of equipment.
A curb and gutter machine is used by road builders to slipform concrete curb and gutter on both sides of a roadway, usually before the road itself is installed. They are also commonly used to produce traffic barriers and parapets.
In operation, the GT-3400 first trims the grade upon which the curb and gutter will be placed to produce a level foundation. This is accomplished with a 24-inch diameter trimmer wheel powered by a radial-piston hydraulic motor.
The GT-3400 can accommodate trimmer wheels from 30-inches to 78-inches long, Pederson said, and wheel position is also adjustable up to 36 inches via a hydraulic side-shift mechanism. There is also a hydraulic lift system with 18-inches of travel for the trimmer head.
Once the base is trimmed, the curb and gutter are formed in place with a slipforming mold that produces the desired contour. The standard mold is up to 24-inches wide, and optional molds are available for various curb and gutter configurations, plus barriers, parapets, and sidewalks.
The mold is attached to a hydraulically controlled drawbar and hold-down assembly that provides up to 18-inches of vertical adjustment, and 30-inches of sideshift. There is an additional 6-inches of manual vertical adjustment available in the system.
Concrete is delivered to the mold with a 14-inch diameter direct-drive auger powered by a radial-piston hydraulic motor. The conveyor mount has 16-inches of hydraulically controlled adjustment, plus manual tilt and slide capabilities to accommodate grade variations. The conveyor hopper is sized to permit slipforming a complete radius without waiting for concrete delivery.
Most people don™t pay a lot of attention to curb and gutter, Pedersen noted, but they really are quite complex and highly engineered features of a roadway. For example, every curb and gutter has what™s called a ˜flow line™ that is basically the line along which it directs water. The ˜flow line™ can be either angled to ˜catch™ or to ˜spill™ water, which means it either directs the water along the curb and into a sewer opening, or it directs the water out onto the pavement.
Typically, the ˜high™ side of a roadway would have a ˜spill™ contour, and the ˜low™ side would have a ˜catch™ contour. But if you think about a typical road, he continued, it will quickly become apparent that the ˜catch™ and ˜spill™ relationship changes constantly with terrain features, curves, and other characteristics.
In the past, it took a lot of survey preparation work and a highly skilled operator to keep everything within specifications. Now, we can simply dial the appropriate information into the G21 control system and the machine will make all of the necessary adjustments ˜on the fly™ producing a near perfect job every time. That™s a big part of the ˜precise™ aspect of the GT-3400.
The 3054E is a 4-cylinder, in-line design featuring advanced emission control technologies that permit it to meet current EPA Tier 2 and European Stage II requirements. Built around an advanced, open-top deck block and equipped with cross-flow cylinder heads, the 3054E delivers state-of-the-art performance and operating economy in a compact, quiet package.
Much of the improved performance of the 3054E can be attributed to the advanced electronic control module (ECM) that is standard on this model. An extremely rugged unit, the Cat ECM is mounted directly on the engine and engineered to withstand the rigors of off-highway and construction industry applications.
Among the advantages of an electronically controlled engine are quicker response to changing operating conditions; improved throttle control; the ability to customize the engine™s torque curve to closely match application requirements; increased control reliability, easy servicing, and the availability of onboard fault diagnostics. The Cat ECM also reduces combustion noise and emissions by precisely controlling fuel delivery and injection timing.
We have found the 3054E to be exceptionally clean and quiet, Kevin Klein, Vice-President of Research and Development for GOMACO, noted, and our customers really appreciate the 500 hour service interval and single-side service accessibility it offers. They also like the fact that Cat engines are supported by a global network of dealers and service centers that makes spare parts and maintenance available wherever these machines are used.
More information is available at http://www.gomaco.com/.
With 2006 sales and revenues of $41.517 billion, Caterpillar is a technology leader and the world™s leading manufacturer of construction and mining equipment, clean diesel and natural gas engines and industrial gas turbines. More information is available at http://www.cat.com/.