Tetra-Folding Gate 21 March 2018, 18:00 Sorry, your browser doesn't support embedded videos, but don't worry, you can download it and watch it with your favorite video player! A combination of slider-crank mechanisms and gears. The gears are fixed with the two center gate panels. « previous mechanism Lining Up Mechanism next mechanism » Self-Centering Fixture load comments Please enable JavaScript to view the comments.