Missing link good for the long haul

Long hours in the tandem or highway tractor can wreak havoc with your back, and obviously with your truck too. The truck can be replaced. Your back can’t be.

Once the truck is damaged beyond repair, it gets scrapped. Unfortunately, the same happens to truck drivers who’ve spent too many hours bouncing up, down, sideways and whichever direction the Earth surface wants to throw them. The career-ending back injury not only terminates the income, it also signals years of pain and further curtailment of all other farming activities.

A top-of-the-line seat today can cost upwards of $6,000. It partially helps isolate the driver from Earth’s surface … but only partially. The truck chassis itself is bounced and thrown in all directions. And the cab, which is not firmly affixed to the chassis, gets its very own rough ride. Buckled into the fancy $6,000 seat, the driver gets the combined rough treatment of chassis and cab shaking independently.

Industry sources say the cab takes a beating at the points where it mounts to the chassis, sending the cab for an early trip to the repair shop or the re-cycling pile. That contact point became an industry concern in the 1960s. As early as 1964, Ford unveiled a prototype highway tractor with a large cab suspended on four leaf spring suspension units. “Big Red” was powered by a 600 horsepower gas turbine. By then, European trucks already benefited from air-ride systems with air-springs and shocks on all four corners. The SAE Mobilus website says a four-point cab suspension provides improved crash safety and reduced dynamic forces at the cab mounting points.

According to Link Manufacturing in Sioux Center Iowa, “Advanced seating has been used to keep drivers more stable and to reduce discomfort. However, advanced seating doesn’t prevent steering wheels, gear shifters and accelerator and brake pedals from moving with dynamic force around the driver. Structural cab components may still be damaged, and the contents of the cab, including those occupying a sleeper compartment, are at risk.

“After transitioning from highway to off-highway conditions, cabs can sustain structural damage, vehicles can become harder to handle and drivers can be forced to decrease speed to avoid losing control. Even at reduced speeds, operators may be exposed to dynamic forces that, according to (ISO 2631-1:1997) standards, can cause internal injury.”

The ROI uses two different types of shock absorbers, an electromagnetic or a hi-tech hydraulic shock. | Link image

Link Manufacturing began their attack on that critical violent interface between cab and truck frame about 40 years ago. Founder Bill Nibbelink was a former cab-over-engine driver who decided by 1980 that he’d had enough of the tortuous ride. Not to take the spinal abuse sitting down, Nibbelink set out to design and build North America’s first cab suspensions employing air bags and shock absorbers.

Now, with over two million “Cabmate” suspension systems on the road, Link has a 40 percent OEM market share in North America. This summer Link introduced their new Road-Optimized Innovation (ROI) semi-active digital Cabmate. This intelligent semi-active cab suspension will positively impact safety, operator comfort, asset protection and driver longevity, according to the Link press release. Link says the new computer-controlled suspension system delivers a new level of ride quality that responds to road and weather conditions.

“We use two very different types of shock absorbers. One is electromagnetic, the other is actually hydraulic,” explained Link’s Rick Ashley.

“The ROI Cabmate Semi-Active Cab Suspension employs two sensors and is constantly assessing environmental circumstances, while responding simultaneously. An accelerometer monitors the motion of the cab, while a position sensor measures the position and velocity of the cab relative to the frame.”

Algorithms in the ECU interpret the stream of information from both sensors in real time, and responds by continuously adjusting the stiffness of shock absorbers and by filling or exhausting air from the air springs to optimize ride stability and comfort. The entire ROI system operates on less than 10 watts of power.

With adjustments hundreds of times per second, the system can respond appropriately at each instant. The operator has a very soft shock when traveling on a smooth highway and a very stiff shock when driving on uneven or off-road terrain. The system deals with unexpected encounters, like potholes, in real time so drivers experience an enhanced ride in a constant state of dynamic dampening.

“You might think the electromagnetic shock reacts quicker to the ECU, but in actual fact the hydraulic shock reacts just as quickly.”

Over the years Link has assembled a world-class testing lab dedicated to cab suspension engineering. Link says their lab data indicated a significant improvement in all areas of measurable quantitative ride quality. But for real-world qualitative differences, Link took to the roads, logging a million miles of field-testing with working fleets in actual working conditions.

The new ROI Cabmate also features electronic height control. The system minimizes air consumption compared to traditional height control valves, because it does not fill or exhaust air in response to dynamic suspension motion. The system is designed to produce a better overall ride regardless of road surfaces and atmospheric forces, such as wind sheer.

“Fleets will find numerous advantages, beginning with protection of the driver and the whole-cab asset. Reducing driver and vehicle fatigue and enhancing ergonomics may enable operators to traverse an uneven route more quickly and safely, enabling productivity to rise and additional runs to be made in a single shift. And what fleet or owner-operator doesn’t want that?”

But, the ROI is not only for fleet operators. At a suggested list price of U.S. $2,000 any farmer with a lineup of trucks should be able to install a Cabmate in every unit that sees a lot of miles.

About the author


Stories from our other publications