With a device called ProCap, Bert Straus says he invented headgear that could reduce concussions in National Football League games. He never got the chance.

The ProCap, which took him eight years to develop, was gaining ground among players until he brought it before the NFL committee dealing with brain injuries. The panel disparaged Straus’s invention, prompting the league to warn players they risked death wearing it. The committee was guided in part by the advice of an outside consultant who once testified for Riddell Inc. (0059072D), the league’s official helmet maker, in an injury lawsuit.