Feb 15, 2011 - 8 years ago
By Supply Post
When Mike Kloepfer got his first “insider’s” look at an earthmoving scraper, he saw a machine in need of some critical examination.
“Scrapers have been around since the 1800s, but they haven’t seen much innovation in decades, really. When we got out and talked to customers, they all told us about problems that they’ve had for as long as they can remember,” says Kloepfer.
Kloepfer and his engineering team became involved with scrapers when a long-time business associate, Jim Bult, came to him with a concept he had to overcome the problems he was having with a large earthmoving project. “Jim was experiencing a number of problems with his scrapers,” Kloepfer continues. “He had a pretty clear understanding of what wasn’t working effectively on his project and a concept of what was required to correct the problems. As he soon found out, he was running into the same problems other scraper operators have been living with for a long time!”
Necessity Meets Invention
For Bult’s project, constructing a new airport site, conventional open bowl scrapers were simply too costly. After purchasing a fleet of tractors and pull-pans, he found the scrapers could not load and move material as efficiently as hoped. Then his tractors, overstressed by the large loads on their drawbars and rear axles, began to fail prematurely.
Bult’s past experience told him that the issues seemed to center on how the scraper loads were getting transferred to the tractor. He started to experiment with his own ideas of how to alter the coupling between the bowl and the power unit. Then, after a few trials, he brought his ideas to Titan Trailers. As a specialist in custom-built highway trailers for heavy-duty hauling, Kloepfer’s appraisal of that first unit was immediate. “Jim’s concept is correct and we can put our engineering team to work on it,” he said.
A New Look And Feel
Recently, Kloepfer made good on his promise to “develop Jim Bult’s concept.” Titan’s new Earthmoving Equipment Division has launched its S4412B scraper system, a 44-yard capacity heavy-duty scraper bowl integrated with a Bell 4206D scraper tractor. Tapping into his experience with trailer customers, Kloepfer invited Jim Bult and several other earthmoving contractors to work with the Titan design team in the machine’s development early on. As a result, the S4412B has a look and feel unlike any previous scraper on the market.
“You don’t have to be an engineer to see the differences,” Kloepfer smiles. “You can spot those huge rear tires and our High Arch Drawframe from a mile away!”
Indeed, those highly visible aspects of the S4412B represent two of the most significant design decisions made by the Titan team to fully utilize the capabilities of its third key component: the Bell scraper tractor.
After developing a prototype scraper, Kloepfer’s engineering and technical support team devoted most of the past two years to testing and refining their scraper on customer jobsites. “Instead of bringing yet another scraper bowl to the market, we aimed for a complete re-invention of the high-end scraper application. We had some new engineering concepts to test for every aspect of the system, from the front-end power profile to a new apron concept to rear flotation. But we needed experienced operators and contractors to help us identify what was working and what still needed improvement.”
Bridging Power to Strength
Kloepfer feels that this scraper’s most important innovation is its High Arch Drawframe, based on the coupler that Jim Bult produced for his experimental scrapers. The distinctive gooseneck-shaped drawframe couples the scraper and tractor through a massive 12 in. (30,5 cm) diameter ball hitch. The High Arch coupling system is the backbone of the scraper and helps Titan achieve several of its design goals.
The problem with other pull-scrapers, Kloepfer believes, is that their design was driven by the shortcomings of Ag tractors. “You see scrapers hooked up to farm tractors that are built for pulling implements behind them, not for hauling heavy loads. The stresses are completely different. The Bell 4206D tractor started life as a heavy hauler, so it’s engineered to carry more of the load. With the High Arch Drawframe, we can put the weight right where it does the most good, ahead of the tractor’s rear wheels. All four wheels carry almost the same weight, so all four wheels deliver more power to the ground. Rimpull at all four drive wheels actually improves as you increase the load in the scraper.”
The articulating and oscillating range of motion of the hitch also improves maneuverability and stability as the scraper moves over uneven terrain which minimizes the transfer of energy from the scraper to the cab – operators get a smoother, more comfortable, safer ride. The compact connection also allows the 55 ft. (1 676,4 cm) long scraper system to turn within a radius of just 39 ft. (1 189 cm), helping operators to work quickly and safely on congested jobsites.
Unlike most modern high volume pull-scrapers, which typically run on 4 tires, the S4412B introduces a two-wheeled running gear equipped with a pair of 100 in. (254 cm) diameter tires mounted on 5 in. (12,7 cm) diameter axles. According to Kloepfer, the four-wheeled standard is simply another holdover from farm scrapers. “Four small tires let you place the axles further forward, so the scraper takes the load off the tractor. That works to a point. But when you move up into larger volume scrapers responding to the need for increased productivity, the inefficiency of a four-wheeler becomes costly. We found that four-wheeled units pulled too heavily; the tires were pushing a wave of soil ahead of them instead of rolling over it. In addition, customers told us that pulling those loads coupled with all that additional weight on the drawbar of the tractor, was just killing their drivetrains.”
“The two-wheel design is actually much more efficient,” he continues. ”On one hand, the wide footprint of the larger tires provides better floatation on soft soils, so it’s easier to pull and takes less fuel. On the other hand, moving the axle to the back of the scraper tips the balance of the load forward, so the Bell tractor carries more of the load it was built for. You need a true scraper tractor to make the equation work, but you need the right-sized rear tires to get your money’s worth from the tractor.”
Bringing ideas down to earth
Before these new theories of scraper design were taken to the market, his engineering team tested the concepts on Titan’s computer modeling systems as well as real-time in the dirt at Titan’s own test site adjacent to the factory. As Kloepfer says, “Our engineering team has an incredible amount of experience solving problems in how to distribute weight, how to stand up against twisting and heavy impacts, and how to move material quickly. And that’s how we approached the design of this new scraper.”
Andy Maertens, Titan’s head of Research & Development, explains that his department uses its own proprietary software to optimize load distribution and axle placements. Then, data collected through testing is processed through Finite Element Analysis programs to refine the structural design of the drawframe and bowl. Design enhancements to the bowl included raised sidewalls to improve the scraper’s load retention through the load - haul - spread cycle. According to Maertens, “With a scraper this size, you put a lot of energy into getting the bowl loaded up. It just makes sense to take some care to make sure the load actually stays on board till the scraper gets to the fill site.”
To further support their design and development team, Titan hired a scraper owner/operator who has more than 40 years of experience in the earthmoving business. His first-hand knowledge as to the performance of all types of open-bowl scrapers and customer expectations has proven invaluable in the development of this product.
All Day, Every Day
“Hydraulic cylinders were another real sore point for the people we talked to,” Kloepfer recalls. “This is one area where you can separate a heavy earthmover from the typical agricultural-style scraper. We got some specialized help to make sure our scraper would be ready to work at maximum loads all day, every day for years to come.”
The hydraulic system of the S4412B provides extreme duty hydraulic cylinders with self-aligning spherical steel bearings at all cylinder anchor points, along with stainless steel lines and 4-wire braid hoses throughout. Features such as heavy duty trunion balls and caps were also a response to customer requests for a simpler more reliable scraper.
While the S4412B scraper system is now officially in production, Kloepfer says this new machine is continuously under development. “Every customer’s application is different,” he acknowledges. “Every project and every worksite gives us a chance to learn something new. That’s how we have been doing business for 35 years and that’s the one thing that isn’t about to change. Between Jim Bult and Titan we have created and engineered a new product that begins a new era in scraper technology.”