Cover Story/Machine Matters: Dynamic duo
| July 02, 2008 |
Pairing a pull-behind scraper and scraper hauler – specifically designed for the task – is teamwork at its best. Pull-behind scrapers work well in light stripping applications with no severe grades or where the material weighs less than 3,000 pounds per bank cubic foot and has no rocks or debris. According to Scott Knoblauch, senior consultant with Caterpillar, if you are working in soft or very poor underfoot conditions, pull-behind scrapers have much higher flotation than self-propelled scrapers.
The haul distance on a job has been a factor in determining whether to use a self-propelled scraper or a pull-behind scraper. Generally, the self-propelled scrapers could travel faster over long distances (usually over a mile) but could carry only one load. Pull-behind scrapers could be linked up to three to a train and carry a greater total of material, but their less powerful towing tractors were slower than the self-propelled machines. Today, purpose-built scraper haulers are combining more pull power and faster speeds to let contractors move more cubic yards of material at efficient speeds.
Since fuel consumption has become a machine decision factor, one advantage of pull-behind scrapers is that they usually require only one diesel-powered engine to move them. Robin Pett, president of UED, which distributes Bell scraper tractors in North America, says the Bell unit uses a scant 13 gallons per hour of fuel, making it less expensive to run than similar capacity self-propelled scrapers that can burn approximately 25 gallons per hour. Keep in mind, however, that you still need to take the cost per yard of material moved. This cost-per-yard figure takes into account operating, maintenance and purchase costs.
The powers that be
While pull-behind scraper manufacturers strive to design scraper equipment that works well with most haulers, and scraper hauler manufacturers build construction-grade haulers, Randy Rust at Ashland Industries says both machines must work well together. Matching the scraper hauler to the scraper will maximize production, decrease down time and provide the lowest cost per yard over the long run.
Regular-duty ag tractors with enough horsepower can be used to tow a pull-behind scraper but they aren’t built to pull heavy material or multiple scrapers through rocky or wet conditions, “A standard ag tractor doesn’t have the proper gear mechanisms,” says Danny Dumey, president of Double D Manufacturing. “If they get into soft conditions, they run out of power and can’t get the job done.” So equipment manufacturers are building construction-grade scraper haulers that take the best from the manufacturers’ power unit lineups.
Scraper haulers such as Cat’s Challenger MT800 Series scraper tractor and Deere’s 9030 Series scraper special tractors are enhanced with stronger frames, reinforced suspensions, autoload systems and more powerful drivetrains.
Volvo’s T450D and Bell’s 4206 scraper hauler models are designed with a nod to the strengths found in an articulated truck like four-wheel-drive, all-wheel ground contact and equal weight distribution during loading and transport.
Both style scraper haulers give you the flexibility to use them to pull other heavy attachments like water tanks, rollers, compactors and rippers. Scraper haulers designed to do multiple tasks give you a better return on your initial investment and will hold their value when it comes time to sell.
In fact, James Hausner, vice president of marketing for Reynolds International, says a key consideration when buying a scraper hauler is the unit’s resale value. “A hauler should be able to be used for several applications. A contractor limits his equipment’s resale value if he buys a machine that only does one thing. The hauler’s versatility increases the contractor’s return on his initial investment.”
Bell Equipment/Universal Equipment Distributors
In January, Bell Equipment of South Africa appointed Universal Equipment Distributors as the North American distributor of Bell scraper haulers. The Bell 4206D is coupled with the Makco M3338 gooseneck pull-behind scraper and the combined unit is now called the Bell 4206D motorized scraper.
The scraper hauler portion of the Bell 4206D motorized scraper is also designed with a nod toward an articulated haul truck. The 4206D’s front suspension is a semi-independent A-frame configuration, with a solid mounted rear axle and is powered by a 420-horsepower Mercedes OM501LA V-6 engine with a six-speed Allison HD 4060 automatic transmission featuring a torque converter and lock-up in all gears. The hauler disconnects from the pull-behind scraper and can be used to tow a water wagon or 50-ton side-dump wagon.
The Makco M3338 gooseneck pull-behind ejector scraper on the Bell motorized scraper features a gooseneck ball hitch design that allows the complete unit – tractor and scraper – to be transported on one 50-foot low-boy trailer, eliminating the costs for two separate hauling trailers. The gooseneck also creates a 50/50 weight distribution from the scraper to the tractor, taking stress off the rear axle. The M3338 scraper has a heavy-duty push block for dozer push loading. The pull-behind scraper has a heaped capacity of 38 cubic yards and struck capacity of 33 cubic yards.
Challenger tractors, manufactured by AGCO and sold and serviced by North American Cat dealers, offer the new Challenger MT800 Series tracked scraper tractors.
The five Challenger MT800 rubber-tracked scraper haulers are powered by Cat ACERT C15/C18 six-cylinder engines with horsepower ratings ranging from 350 to 570 horsepower. Cat’s 16-speed push-button, powershift transmission propels the MT800 to a maximum speed of 24 mph.
Challenger’s Mobil-Trac system, combined with the Opti-Ride suspension system, improves balance and traction and reduces compaction. The special application belts on the adjustable undercarriage are designed for dirt scraper operations and feature 2.5-inch-tall tread bars to improve cleaning and reduce tread bar flexing. Real-time track tension is monitored and changes on the left or right belts are displayed individually on the tractor management center console. All MT800 series scraper models have a standard scraper hitch plate that will withstand up to 20,000 pounds of vertical loads from semi-mounted units.
In January, Caterpillar acquired E-Ject Systems in Elkader, Iowa, and Cat dealers in North America are the exclusive suppliers of four pull-behind scrapers models now with the Cat brand.
The two wheel E-17 and E-22 scrapers and E-17XW and E-22XW four-wheel scrapers have load capacities of 17 and 22 cubic yards and feature high-strength construction. The four-wheel configuration features a walking beam suspension that reduces side-to-side sway and smoothes the ride in the cut and on the haul road. All four models are designed to be pulled by AGCO’s MT800 and MT900 Series Challenger tractors.
Deere’s system mates the new Deere 9030 Series Special Tractors with the Deere fixed-blade ejector or carry-all pull-type scrapers. The Deere 9430, 9530 and 9630 scraper haulers, introduced last fall, are attractive to contractors who need a high-horsepower, rugged pull unit for pull-behind scrapers but also have applications that require features found on an ag tractor. The 9030 Series, based on Deere’s 9000 Series ag tractors, is powered by the John Deere PowerTech Plus 13.5-liter engine that produces up to 530 horsepower. An 18-speed PowerShift transmission is standard on all 9030 series scraper tractors. Deere’s AutoLoad option is new to their 9030 Series this year. AutoLoad automates the scraper’s hydraulic lift functions for faster repetitive loading and shorter cycle times. For additional support, Deere’s scraper-special tractors have front frame/axle reinforcement to accommodate high loads on the front end of the machine. Reinforced rear axles are standard on the 9530 and 9630 models.
Deere has added two more pull-behind scrapers to its lineup and says their new heavyweight 18-cubic-yard 1810C carry-all scraper and 21-cubic-yard 2112E ejector scraper feature side frames that are 43 percent stronger than previous models and the overall width of the side arm is narrower for closer cuts to grade stakes. A more robust gate tower and heavy-duty gate arm increases pinch force by 25 percent. Deere also says the upgraded blade support is 50 percent thicker and 100 percent stronger than current models. A new steeper-angled overflow guard makes top-loading easier. The cut width on the 2112C is 12 feet and 10 feet on the 1810C model.
Richard Iddins, product marketing manager for Volvo Construction Equipment, says the T450D is a direct result of Volvo customers asking for more pull power, flexibility, durability and speed.
Volvo’s T450D scraper hauler draws from the DNA of their articulated hauler family. The T450D’s 12-liter, six-cylinder, 419-horsepower Volvo D12D engine provides the muscle required to pull up to three scrapers depending on the scraper configuration and total weight.
The Volvo T450D scraper-hauler’s three-point A-frame independent suspension system on the front and rear axles allows each wheel to move independently over uneven or rocky terrain, increasing stability and reducing stress on the hauler’s frame. Dual circuit, wet-disc, oil-cooled service brakes on all wheels and a variable hydraulic transmission retarder safely slow the scraper-hauler and its attachments.
The T450D’s drivetrain is designed specifically for the jolting operations found on a construction project. Equipped with Volvo’s own automatic planetary transmission, the T450D has a four-by-four drive with five operating modes to match operating conditions and can operate at a smart clip of 32 mph for faster cycle times.
Operator controls include the scraper mode that automatically controls the speed of the scraper hauler for efficient loading. A vehicle information system monitors all fluid levels and displays the machine’s status in the instrument panel, minimizing service times.
In May, Volvo and Ashland Industries entered into an agreement that will allow Volvo dealerships to sell Ashland I-180TS2 scrapers. Ashland’s I-180TS2 heavy-duty 18-cubic-yard capacity ejector scraper features a 15-inch two-part pushbar extension system that protects the quick hitch and assists in loading in short distances. The scraper’s 126-inch cutting width allows fast loading and the 56-inch apron opening eliminates the need for double or triple ejecting in heavy soils. The heavy-duty hold-down roller in the sidewalls makes for easier ejection.
Icon’s front lowering, eject style scrapers are available in a two-wheel 819 model and the four-wheel 821 model. The Icon’s electronic Operators Reference Gauge system, a standard feature on the 819 and 821, gives the operator precise feedback information on the height and depth of the cutting bit and front load gate. Both models have heavy cast 360 swivel Quickhitch couplers and hydraulically operated disc brakes on each axle. The 819 has a heaped capacity of 19 cubic yards and the 821 will carry 21 cubic yards. Each model has standard double wall construction on the sides. A push block is standard on the 821. Icon highlights the narrow transport width of these scrapers, the 819 being only 10 feet 11 inches wide and the 821 just 1 foot wider. Recommended maximum horsepower for a wheeled or track tow unit is 600 horsepower.
K-Tec’s new 9.525 scraper is designed for narrow applications with a cutting width of just 11.6 inches. The 9.525’s heaped capacity is 25 cubic yards and fitted with LGP tires. Also new for 2008 is the K-Tec 1453 scraper that features a 53-cubic-yard heaped capacity, the largest available according to the company. The 9.525 scraper requires 300 horsepower and the 1453 needs 500 horsepower.
The Leon 1700 17-cubic-yard capacity scraper features heavy duty ball-type steering for rough or difficult pulling conditions. The front hydraulic push ejection system works with the tractor’s hydraulics to eject wet or sticky material in one pass. Side extensions are standard on the M1700. The scraper requires a maximum of 425 horsepower.
Double D Manufacturing
The Grade King Series leveling scrapers, built by Double D Manufacturing, are designed to work with extreme-duty wheeled or track pull units with maximum of up to 525 horsepower. To increase the scraper’s flexibility, the Grade King can tow addition implements behind itself like compacting rollers, smooth drum rollers and Double D’s own Roll-N-Go sheepsfoot compactor. Options include a scarifier, a hydraulically lifted smooth drum roller, rear hydraulics and an aggression bar for grading gravel roads.
Miskin’s new E Series 20-cubic-yard scraper, Model E-20, features a ‘push-off ejector’ bowl that handles sticky material neatly. “The E-20 cleans its own floor and sides each time it ejects, leaving no place for dirt to hang up,” says Mark Miskin, president of Miskin Scraper Works. The E-20 also features Miskin’s CushionRide suspension that protects the scraper at high travel speeds and in rough terrain. Disc brakes are available for applications involving steep grades.
Reynolds LGP high flotation special application scrapers are self-loading, applicable for excavating, transporting and spreading sand and wet materials. The 43-inch-wide super flotation tires eliminate mud buildup between side walls and reduces tire rutting for better ground speed. The RoughOut scrapers, Models 16CS10 and 17CS12, feature three piece reversible cutting blades with a permanently protruding center section that will not cut flat. Reynolds high flotation special scrapers can train up to three units for large scale applications. Suggested horsepower range is from 250 horsepower for the 14CS10LGP model to 400 horsepower for the 17CS12LGP model.
Caution: Respect your transfer weight
Ashland Industries CEO, Randy Rust, stresses that no matter which manufacturers’ scrapers or scraper haulers you prefer, it is imperative you understand and abide by the hauler’s transfer weight restrictions. You have to match your scraper’s capacity to your scraper hauler’s transfer weight. Here’s why:
According to Rust, each scraper hauler has a specific weight limitation and/or yardage capacity. Pull-behind scraper manufacturers are working with the scraper hauler makers to make sure their scrapers are designed to work within the scraper hauler’s specifications, but you should still ask your dealer what the ‘transfer weight’ is for your machine. The dealer may give you a percentage figure (based on the number of cubic yards multiplied by the material density), a cubic yard capacity number or a specific pound limit.
It is just as important to know your pull-behind scraper’s tongue weight. When you hook a fully loaded pull-behind scraper to your scraper hauler or tractor, the scraper’s weight distribution changes. Some of the pull-behind scraper’s weight transfers – rolls on – to the hauler. By staying within the weight limits set by your scraper hauler manufacturer, you can avoid significant damage to your scraper hauler during operations. Overloading the scraper hauler’s static weight limits can result in such things as rear axle deflection, bent wheels, lost lubrication seals and cracked frames. Understand your scraper hauler manufacturer’s warranty specifications so that you do not violate your warranty. Rust says this caution is especially important for scraper haulers towing only one scraper. Scraper haulers pulling multiple scrapers will disburse some of the transfer weight stress between the scrapers but on a single scraper hauler/pull-behind scraper pairing, the hauler takes most of the weight.
Another thing to consider is how your scraper-hauler combination will stop. The International Organization for Standardization regulation ISO3450 has established a minimum performance for brake systems on earth moving machinery. Your hauler may have the strength to pull your scraper and material, but it needs the ability to safely come to a halt.
Additionally, each scraper should have brakes that allow it to stop by itself. If either your scraper or your hauler isn’t rated to work with the other, you risk damaging your equipment and putting your operator in danger. Consider the hefty fines OSHA or MSHA can levy if they find the scraper and hauler are mismatched. An example of a scraper/hauler combination that meets the ISO3450 requirements is Volvo’s T450D hauler and the Ashland I-180TS2 scraper.