Wooster, OH —When consumer product giant Rubbermaid designed a new cooler called the 1957 Survivor XC, they were thinking about what happens when loaded coolers slide around on the smooth surfaces in the backs of SUVs, pick-up trucks, and other vehicles.
The 1957 Survivor XC is made from a slick polyethylene shell, so design engineers decided on pads for the bottom of the cooler—particularly good for abrupt stops and sharp turns. Each cooler would have four pads, two to three inches wide, which would cover the cooler's four feet. The company's concern was that they did not add too much cost.
Rubbermaid asked engineering firm R.L. Hudson (Tulsa, OK) to design the pads. The company initially considered 3-inch wide by 5/8-inch wide deep lathe cut rings. The rings covered the feet, but were visible through the opening and that was not acceptable.
Rubbermaid then suggested molded rubber cups, but the cups would require an adhesive. "With adhesive, you'd have to have someone clean the surface, peel away a pressure sensitive label, position the cup, and press it on," says R. L. Hudson Vice-President Roger Stair, who was directly involved with the design process. Applying the adhesive manually would also have made product consistency hard to verify. Finally, adhesive wears out over time, so the design team was concerned about how long a cup would stay in place.
The engineering teams then considered the possibility of a barb molded into each cup's center that could snap into an opening molded into the bottom of the cooler's feet. Adding the openings in the cooler feet without adding cost was feasible because the cooler would be injection molded and the opening could be worked into the mold. The change would add no cost.
Hudson suggested making the barbs hollow. Hollow interiors would allow the parts to flex easily as they went into the openings. The hollow barb also made the part easier to remove from the mold during production.
At this point, the design seemed plausible, but cost was still an issue. So Hudson suggested eliminating the cup's sidewalls, thereby reducing materials and bringing the cost into range. With the walls gone, the cups became pads and the design was completed. The peripheries of the pads are encapsulated by thin lips molded into the cooler's shell.
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