Patent Archive · Steam Traction Engines
Converting a stationary portable steam engine into a self-propelled road and field locomotive required solving three severe mechanical problems: boiler stress over rough ground, steering under load, and differential wheel speed on turns.
Because rigid axle brackets transmitted road shocks directly into riveted boiler seams, Buffalo Pitts engineers patented coiled and leaf spring suspension brackets that allowed the rear drive axle to articulate without straining the firebox side sheets.
To allow an operator to engage the traction drive smoothly while the engine flywheel spun at belt speed, Buffalo Pitts patented expanding-shoe friction clutches and enclosed bevel-gear differentials that distributed torque evenly to both rear drive wheels.