Suicide knob or necker's knob.
Running boards, as Maxwell Smart found out...
Is that what it was? A steering knob that cost him his eye? I thought it was some sort of a design on the center of the wheel where the modern-day horn button is now.
Per the Beacon Journal, the impact caused his face to hit the steering wheel, which featured a conical horn button in the center. Striking that protrusion popped his left eye out of the socket, fractured his face, and injured his back.
Read More: https://www.grunge.com/416943/how-sammy-davis-jr-lost-an-eye/