Christie suspension

The Christie suspension is the name of a suspension system developed by American engineer J. Walter Christie (1865–1944) for military vehicles, especially tanks. This system allowed for considerably longer movement than the leaf spring system, which was commonly used at the time. Aside from faster maneuverability, the Christie suspension used individual road wheels with tyres that allowed a tank to be used without treads.

History

J. Walter Christie, an American engineer and inventor, envisioned a lightweight tank with long range capabilities and high speed that were designed to penetrate enemy lines and attack their infrastructure and logistics. His first prototype of 1919 could be driven on its wheels to get to the desired point and have its tracks quickly fitted on at its destination. This prototype, designated as the Christie Model M1919, was delivered to the U.S. Army for testing, which was then approved on 8 June 1920. Christie later proposed another modification to add coil suspension to the front wheels of the tank and removed the turret, relocating it to the nose of the tank. The modified tank, designed M1921, debuted in 1922 but was rejected this time as it was deemed unsafe and unreliable due to lacking in maneuverability and internal space.

In the late 1920s, Christie modified his suspension system to add a bellcrank that could change the direction of motion from vertical to horizontal. The road wheels were individually mounted on a pipe that could move vertically only, at the top of which the bell crank rotated the direction of motion to the rear.