SpecialFocus

by Pete Daumeyer, CartierWilson LLC

From forklifts that run in a distributor’s warehouse to large cranes that tower over cities as they grow, heavy equipment is everywhere. While there are several mechanical products used in the machinations of these apparatuses, there is more to it than they nylon used for sheaves.

For instance, polycarbonate (PC) is often used in the windows and sunroofs of cranes, front loaders and backhoes that lift heavy objects overhead. The PC helps protect the operator if any of the product falls. The impact resistance of PC far outlasts that of standard glass for these applications. Some equipment experiences “blast back” during operation; in those cases, PC is necessary to protect the operator from injury.

Standard and enhanced nylon products are often used for sheaves on moving parts. The friction resistance isn’t the most necessary component of a sheave, but some products are filled with molybdenum disulfide (MoS₂) for more lubricity. These sheaves must also carry substantial weight, so the component must have good structural integrity number, counting on a low cold flow specification.

Asphalt paver and compactor demonstrating that performance plastics can work in the harshest conditions. The clear materials surrounding the drive protects the operator from debris while allowing for clear sight lines.

Most cranes will engage in outriggers to steady themselves. A wide base is necessary when lifting large products and extending over a great distance, like lifting a steel beam to an upper floor of a building. These outriggers extend several feet from the crane and have a metal pad to engage the ground. However, often the operator wants a better base than offered by the factory crane, so outrigger pads are deployed. Usually made from ultra-high molecular weight polyethylene (UHMW-PE), these pads are cylindrical in nature with handles built into the outsides. The structural integrity of the UHMW-PE decreases the cold flow of the plastic, allowing for several thousand pounds of downward force to have little to no effect on the pad.

Everything from small skid steer loaders to large front-end loaders to backhoes have many moving parts. Most of the buckets are driven by large gears that require frequent lubrication to keep pistons running smoothly. This lubrication can get everywhere, and all those moving parts require some type of bushing to allow the metal arms and wheels to move with little friction. These bushings are generally a nylon or acetal to allow movement, but still have the chemical resistance to not break down when that lubrication spreads itself around the machinery.

Heavy equipment is vital to building, and anyone who has done a large job knows that the right equipment will make the job a lot easier. The equipment must be safe and low maintenance, while running as efficiently as possible. Performance plastics, when used correctly in heavy equipment applications, can create a safer working environment and longer lasting parts.