A joy stick including a housing having a ball joint. A lever having a pressing part extending radially outwardly is mounted on the ball joint. A plurality of push rods are mounted in the housing and are urged upwardly by a spring for engagement with the pressing part of the lever. The plurality of potentiometers...http://www.google.de/patents/US4812802?utm_source=gb-gplus-sharePatent US4812802 - Joy stick
