The compressed air would fill the cylinders, forcing the gun to rise on toggle-jointed arms, so that the muzzle was above the bomb-proof wall.
"Tom Swift and his Giant Cannon" by Victor Appleton
Printing-press, invention of the toggle-joint, iii, 47.
"Little Journeys to the Homes of the Great - Volume 14" by Elbert Hubbard
Then Earl Stanhope in England invented a press entirely of iron, and the power consisted of the combination of a toggle joint and lever.
"Inventions in the Century" by William Henry Doolittle