Speed is of the essence. Hallco Industries Inc, one of the pioneers of walking floors, offers an accelerator for faster unloading of traditional MSW. It decreases the traditional three-stop retraction to two-stop retraction and ejection, explains Ricardo Aguinaga, regional sales manager, although, he adds, “for material that doesn’t bind, you still need all three steps. It’s not for C&D or anything with slurry; that’s too slick.”
Speed is important for different reasons, Aguinaga speculates. “Everyone wants faster, but do you need faster? The average trailer doesn’t make lots of loads—maybe one to five trips a day.”
Speed is important, agrees Mike Robinson, sales director for Keith Manufacturing Co., which began supplying walking floors to the ag, forestry, and waste industries in 1973. “Before walking floors, we used heavy chain. But it was important to unload quickly. With a walking floor, a truck can unload in 3–4 minutes and get back out.”
Moving, or walking, floors facilitate speedy unloading of MSW at landfills, in part, by reducing handling. The Walking Floor system from Keith Mfg. is equipped with the Keith sweep system. “The driver doesn’t need to get in the trailer,” explains Robinson, adding that it leaves little residue behind in the trailer.
Unloading
Whether or not they need to save time, trucks equipped with moving floors can offload simultaneously because they don’t need specially constructed tipper platforms. Tipping trucks frequently have to wait in a queue until the platform is available, resulting in wasted time for drivers and loss of productivity.
Because small landfills do not have the tonnage to justify an expensive tipper and busy landfills often lead to long wait times, the walking floor refuse trailer, with its flexibility to unload at any landfill, is preferable, states Charlie Benton, refuse trailer product manager and southeast regional sales manager for East Manufacturing Corp., who adds that “a walking floor can be tipped as a tipper if needed.”
As an added bonus, trucks with walking floors can unload virtually anywhere because the ground doesn’t have to be level, Robinson explains. “There’s a lot of unstable ground at landfills, which can lead to tipping trailers falling over, but the walking floor trailers don’t tip over.”
Walking floors make offloading safer as well as faster. Robinson explains that if the wind speed is over 20 miles per hour, tipping trucks can’t operate. “The drivers have to sit and wait for the wind to die. That takes even more time. As many as 50 can line up—and it’s worse on a really windy day!”
Wind and weather don’t matter to a truck with a walking floor, Robinson continues. Nor are there any power line issues, because the trailer remains vertical. Height restrictions don’t limit moving floors as they do dump trailers and tipping trailers; overhead obstructions such as power lines don’t interfere with the offloading process. Trucks can offload inside MRFs and transfer stations with greater ease, providing flexibility in addition to safety and speed.
Whether or not speed is vital, walking floors provide other advantages. The hydraulically driven conveyance system automates loading and unloading of goods by “walking” the load through the rear of the trailer for discharge without having to raise the trailer. Not only does this eliminate the need for a tipping trailer and platform, but it also bypasses the necessity of a forklift to enter the trailer—a time-saver as well as a safety advantage.
Safety is a key feature of moving floors. Thanks to their automated action, these systems reduce handling time—for efficiency and safety. Bag openers can be incorporated into the system to prevent additional handling.
Although walking floors typically remove the need for the driver to enter the trailer to unload material, there can be occasions when it’s necessary for a driver to gain access. To enable safe access, MAC Trailer Enterprises introduced a Man-Door in the bulkhead. “This option allows the driver safe access into and out of the trailer,” says Matthew Simmons, product manager—Waste Division. “Safety and driver retention are huge in today’s market. We offer several different Man-Door options, which can be adjusted, depending on what catwalk/ladder configuration is chosen.”
Leaks, Slats, and Floors
A moving floor is essentially a system of parallel slats that move independently, arranged horizontally along the length of the trailer floor. Divided into sets of three, with every third slat connected, they are hydraulically powered to move forward and backward, creating a “wave” motion that lifts and pushes waste to the open rear door of the trailer for offloading, or toward the cab for loading. When all sets move in unison, the load is moved toward the rear—or toward the front, depending on the direction selected.
For the past 30 years, the standard walking floor system has consisted of 24 moving slats, Robinson states. The 24-slat profiles have rubber seals that can be torn out or otherwise destroyed. They also leak as the truck drives down the road. Keith’s V-9 system is “more leak-resistant than the standard system because it seals in a different way.” There’s no rubber seal on any of the 9–18 moving slats. Even calculating five loads a day, five days a week, he says it will be five years before maintenance is required.
Leakage has long been an issue for walking floors. “Garbage juices leak between the moving slats,” explains Robinson. However, he says, since the early ‘90s, Keith has had a 100% leak-proof system. “There’s nothing dropping out of the trailer.”
One of Keith’s innovations is the floor in their V floor system. Made of steel, the V floor system is capable of holding up to 12 inches of moisture in a solid pan. More expensive than other floors, Robinson says it’s worth the expense, especially in certain cities and counties that want absolutely no leakage on their streets.
Hallco, known for its high-performance Live Floor conveyor system with bidirectional moving slats, also offers a leak-proof system. Their leak-proof Y floor has been used in Hawaii, where moisture and leakage are major concerns. “It works with traditional slats,” says Aguinaga, “or with a raised subdeck.” It also mounts on the top of a flat floor.
One leakage issue Aguinaga raises is that for decades, a floor’s hydraulic system was mounted under the trailer. As trash leaked, it—and maggots—fell on the mechanic working underneath the truck. The Brute front-mount drive system eradicates that problem and is easy to mount on the trailer, Aguinaga says. Putting the hydraulics out front in front-mount systems means the mechanics are also out front, standing up to work on them, rather than lying under them. “There’s no ‘yuck’ factor.”
Keeping the mechanics in mind, Hallco has introduced a new way to mount bearings. “It goes subdeck, bearing, aluminum top deck,” demonstrates Aguinaga. He estimates a savings of two and a half to three hours of installation time with Easy Bearing and Easy Subdeck. The full-length bearings secure to the full length of the system and absorb impact. They also “keep crud and road grime from getting under the slats.”
The Weight—Not Just a Song by The Band
Trailers equipped with a moving floor allow a landfill site to avoid the capital costs accompanying a tipping platform. Even if a trailer didn’t come with one, a walking floor can usually be retrofitted, replacing heavy-duty hydraulic lift jacks that raise the trailer for dumping. However, additional hydraulics and a reservoir kit are required to operate the floor, adding costs and weight.
Weight is always an issue in the MSW world. Robinson points out that tippers are commonly about 3,000 pounds lighter, granting them more capacity. However, he adds, the wait time at landfills is longer and they are even banned at certain landfills.
Tipper trailers maximize payloads, Simmons agrees. However, waste can accumulate around the tipping platform, and the site [operator] has to clear this waste away at regular intervals, resulting in further delays.
Hallco uses 6061-T aluminum as a component of the trailer to reduce weight, reserving steel for specialized applications, Aguinaga says. “Aluminum provides a balance of strength and friction.”
Genesis refuse trailer
Keeping the trailers at a lighter weight helps drivers comply with what Aguinaga calls “odd bridge laws” in some states. To comply with those odd bridge laws while maximizing loads, Hallco offers the Brute, which moves weight from underneath the trailer to the front.
“We use the tractor axles where you don’t normally get payload,” he explains. For states like Michigan, where trailers commonly have seven axles, with each axle carrying a 15,000-pound hauling capacity, he says there’s precious little space to place the drive unit. The Brute is a front-mount drive unit, only 18 inches deep, 12 inches tall, and 20 inches wide.
While a moving floor trailer and a tipper trailer haul the same products, and in the same lanes, their functionality is very different, according to MAC’s Simmons. “Some would say that the [moving floor’s] ability to load and offload anywhere is key to their operation, while others say that the lighter tare weight and reduced maintenance [of a tipper] is key to theirs. It’s a choice that’s very specific to how the customers operate. At MAC Trailer, we have spent a great deal of time and energy on building the most advanced trailer in the industry.”
According to Simmons, MAC Trailer has also focused on reducing the cost of ownership by listening to their customers’ needs and building a specific trailer tailored to the environment in which they operate or the haul they must run. “Rather than take a generic trailer and have the customer make do, we build a trailer specifically designed to help them be as productive and efficient as possible.”
Tip of the Day
Efficiency and productivity are enhanced when the payload is maximized, as it is in East Manufacturing’s new lightweight Tipper trailer. East reengineered the Tipper trailer by removing 1,200 pounds of excess weight from the fifth wheel plate area, the suspension sub-frame, and the sides of the trailer body. This “weight loss” enabled it to increase payload.
In addition, a new aluminum bumper assembly replaces the previous steel bumper, and double-wall construction of smooth-sided aluminum (in both the Tipper and the Unloader, a walking floor trailer) is not only lightweight, but also more aerodynamic and fuel-efficient, while still strong enough to handle the stress of hauling refuse in harsh conditions.
The design is easier to clean, Benton says, and will not show any dings on the outside like traditional external post walls. In addition to protecting the outer walls from dents (which will improve resale value), the design resists bowing and decreases maintenance and repair.
The advanced wall-to-floor construction secures the critical point for trailer strength—the welded union of cross members, floor plates, and sidewalls. “For a super strong floor-to-wall attachment joint, cross members and floor plates interlock into the bottom rub rail, forming a pocket to accept the sidewall panels,” elaborates Benton, adding that the outboard Genesis design “provides more capacity than traditional external post trailers.”
Comparing Issues
There are numerous differences between a walking floor and a tipper refuse trailer, Benton continues. Perhaps one of the biggest is that the tipper refuse trailer is typically used for high-volume loads, using a landfill tipper to discharge the load. “Landfill tippers typically cost around $500,000 so only high-volume landfills that exceed 500 tons per day can support the high cost of a tipper.”
No matter how affordable or efficient a trailer is, there are bound to be a few inherent issues that any trailer has to overcome, and some that are specific to a moving floor. Common issues include corrosion, fatigue cracking, leaking, and other environmental challenges.
Corrosion is a very real and concerning problem, Simmons says, especially with all of the liquid ice control products that are put down on the roads today. “MAC Trailer has specifically focused on reducing the amount of steel-to-aluminum contact points. Where we do have steel-to-aluminum, we use galvanization, Eck, and mylar as barriers to prevent corrosion. On our moving floor trailers, we use stainless steel hydraulic pipe ILO carbon steel.”
Maintenance is an ongoing cost of operation, but when it’s minimal and simple, those costs are low. Keith’s self-contained moving floor unit requires little maintenance, according to Robinson. “Maintenance is simple. There are three hydraulic cylinders—no chains, gears, or bearings—and no lube, unlike belt or chain systems.”
Price is always an issue, but when comparing a tipping trailer versus a walking floor, the latter excels in safety, volume, and flexibility. In fact, you can use the floor of the trailer for other products when not hauling MSW. Aguinaga says it’s possible to drive a forklift on to load, and that some use the trailer to pick up pallets.
In most cases, a walking floor’s speed and versatility outweigh a tipping trailer’s performance…literally and figuratively.