Rock-ola 1930s pinball parts

[coppinpr]

That was my first thought, and I searched to see if one existed but found none. Problem was I suspect you can't patent the concept only the design which could easily be "slightly" changed to avoid the patent. Most of the pinballs I had back in the 1970s used the standard mercury switch, but I remember many with the metal pendulum hanging in a metal ring which cut out the power if the two touched.

Continued here: The first anti-tilt mechanism - Site Admin.