Truckers are getting better sleep in their "homes away from home," thanks to composite sleeper boxes and cab floors manufactured by Canadian Commercial Vehicles (CCV, Kelowna, BC, Canada). Incorporated on Western Star (Willoughby, Ohio) semi-trailer trucks to decrease noise and weight and increase payload and durability, the 2.4m/8-ft wide by 1.4m/4.5-ft high by 1.8m/6-ft long sleeper boxes (not including the streamlined roofs) are built to Western Star design requirements by CCV, using standard laminated honeycomb-cored sandwich panels.
The panels range in thickness from 12.7 to 63.5 mm (0.25-inch to 2.5-inches) and are typically 1.4m/4.5-ft tall by 0.9m/3-ft wide. Polypropylene honeycomb core cell sizes are selectable, to meet designed compressive strength. Foam-filled core also can be used to increase insulation and damp road noise (R values range from 2.5 to 6 depending on panel thickness). CCV already manufactures assemblies up to 203 mm/8-inches thick for extreme load applications, such as heavy-duty portable flooring. The facesheets, typically aluminum, are bonded to the core with epoxy, methacrylate, polyurethane or hybrid adhesives, depending on the application and load requirements. (CCV has been successful in other applications bonding fiber-reinforced plastic (FRP) sheets to the core for the RV and boat industries.) The bonded panels are cured for 0.5 to 1.5 hours in custom-made autoclaves, with independently controllable heat and vacuum. Autoclave curing enables CCV "to fabricate components for up to 15 sleeper boxes per day," says Edison Reis, CCV's engineering/quality assurance manager, "and the vacuum removes trapped air, a critical step in maintaining a Class A finish." Curved panels require a two-step process -- formed first on a mechanical press and then vacuum bagged and moved to the autoclave for cure. The cured panels are cut, CNC routed and/or drilled for cutouts and other options. After machining, hardware is added, and the floor, side and back walls are bonded together, using structural adhesives and sealants. An entire sleeper box can be taken from raw material to final product in about 20 hours. "We are presently shipping 12 to 14 sleepers per day to the Western Star plant in Portland, Ore.," says Reis. To date, CCV has fabricated more than 6,000 sleeper boxes.
The honeycomb-cored boxes are 80 and 60 percent lighter, respectively, than boxes of steel and aluminum only," say Reis. "[This] reduces vehicle weight by up to 385 kg/850 lb." Corrosion- and water-resistant, fully recyclable and repairable at most auto-body shops, CCV sleeper costs, says Reis, are similar to or only slightly higher than for steel or aluminum sleepers.