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Peggy Malnati; Malnati and Associates
KEYWORDS: Pickups, Reinforced Plastics, Safety, Pickup Bed, Integrated Step, Tailgate, Pickup Box
Pickup trucks have traditionally been a difficult market for plastics to penetrate, in part because many pickup owners and OEM engineers thought plastics lacked the strength and durability for construction sites, farm and ranch work, and other rough-duty usage. Fortunately, thanks to recent successes like the composite pickup box, many engineers are taking a second look at plastics in this vehicle segment, which has led to a number of very-innovative applications that save weight, increase fuel economy, reduce dents, eliminate rust, and/or increase vehicle safety and functionality.
One great example is industry’s first OEM integrated tailgate step on 2008 model year (MY) Ford Super Duty and now 2009 MY F-150 pickups. Designed jointly by Ford Motor Co. (Dearborn, Mich., USA) and Multimatic Inc. (Markham, Ont., Canada) and produced by Multimatic, this clever application helps make it safer and easier for customers to enter and leave the vehicle’s bed without needing to jump on/or off the tailgate or drag a box around to facilitate entry and exit.
The tailgate step system is accessed by dropping the tailgate, pulling the "cap" (really the step) straight out from the end of the gate, lowering the step (which gravity and geometry hold in the correct position), and pulling up an integrated handle for added safety. The step and handle easily fold and stow back inside the tailgate when not in use and the system is nearly invisible in its closed position, yet always available if needed.
Although primarily steel, several key components in the multipiece system are reinforced plastics. The first is the step cap, which also functions as the release lever. It is injection molded from 30% glass-reinforced polypropylene (A. Schulman Inc., Akron, Ohio, USA). The cover/cap, incidentally the largest component in the system, has an undercut and 3 ribs designed in for better finger-grip control when pulling the step out from the tailgate. The smaller, inner step component features integral clips, pivots, and T-stops entirely molded in plastic without steel reinforcement. The system also makes use of multiple acetal (DuPont, Wilmington, Del., USA) moldings used in the roller assembly and slide guide subassemblies. The acetal rollers are insert-molded over steel straps.
Although primarily steel, several key components in the multipiece system are reinforced plastics. The first is the step cap, which also functions as the release lever. It is injection molded from 30% glass-reinforced polypropylene (A. Schulman Inc., Akron, Ohio, USA). The cover/cap, incidentally the largest component in the system, has an undercut and 3 ribs designed in for better finger-grip control when pulling the step out from the tailgate. The smaller, inner step component features integral clips, pivots, and T-stops entirely molded in plastic without steel reinforcement. The system also makes use of multiple acetal (DuPont, Wilmington, Del., USA) moldings used in the roller assembly and slide guide subassemblies. The acetal rollers are insert-molded over steel straps.
Because of the success of the stepgate application, which has a 50% take-rate at the automaker, Ford subsequently commissioned Multimatic to develop another industry first -a box side step, which makes it easier for users to access the front of the pickup box and debuted as an optional component on 2009 MY F-150 pickups with 6.5- and 8-ft Styleside pickup boxes. On both driver and passenger sides of the box, an 11-in./279-mm step extends out from the box with the push of a button and then pushes back in place beneath the underside of the box where it is mounted firmly to the frame. Each step can support 500 lb/227 kg of weight. Ford's F-150 can also be ordered with the tailgate step option -with or without the box side step system.
The box side step is another hybrid metal/plastic assembly. Components with the most-significant plastic content include the step cover assembly (molded from thermoplastic polyolefin (TPO); the side covers (also TPO), and the actuating button, which is a combination of glass- and mineral-reinforced nylon 6 (BASF Corp., Wyandotte, Mich.).
Since both steps are safety features and need excellent durability and predictable performance, they were comprehensively evaluated in both laboratory and field durability tests and had to pass extensive component-level testing as well. Both applications represent major new pickup innovations and are covered under multiple patent filings.
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