IMM Focus: Materials 19993
March 1, 2003
It turns out that improving helmet design for the NFL is easier than eradicating bad calls, or at least more straightforward. A design team at Riddell, helmet supplier for several major league sports, decided to make greater protection their goal in creating the newest addition to the football lineup, dubbed the Revolution or Revo. In so doing, the team elevated the molded polycarbonate helmet to the forefront of materials innovations.
Plastic suspension helmets were invented by John Riddell in 1939 and worn by allied troops during World War II. From this initial design, the current football helmet was born. Molding it from PC is a relatively recent step, begun five years ago, according to Riddell designer Thad Eid.
“For the Revolution, we started with protective criteria, which then drove all other design considerations. Once we established these criteria, we went to the CAD design, a Pro/E file of the shell, and had an SLS prototype made by Modelex in Quebec.â€
Eid and his team worked with GE Plastics testing the impact-modified Lexan PC chosen for the helmet. “Protection and durability were the keys,†he says, “derived through materials and shell design. We reinforced the shell in places where we thought there would be durability and wear issues. GE did moldfilling analysis for us, and checked different runner and gate configurations for optimum molding.â€
Revo’s design is based on a long-term study of NFL players who suffered concussions on the field. Using NFL films, researchers studied concussion-causing events to determine the speed and angle of impact, and then recreated it in a lab using dummies. The study determined concussion tolerance curves; from this data methods were developed to test helmets reliably without repeatedly using dummies.
Side impact came up as the big factor in concussions. Traditional helmets include padding in the jaw area for fit. With Revo, designers added shock-absorbing materials in the side of the face and made the helmet wider.
Shell design considerations also included staying within a modest tooling budget and minimizing the number of slides. “We wanted a reliable tool that needs less maintenance and less downtime,†says Eid. The company’s goal is to produce 100,000 units per year at a retail price of $150.
You May Also Like