Pneumatic suspension for twin reat axle - with fail safe velve to prevent nondriven axle lifting under heavy loads

摘要

The vehicle is provided with two rear axles fitted with pneumatic suspension. One axle is driven and the other trails. The trailing axle has a retractable suspension so that it can be lifted clear off the road at low loadings, and is brought down into contact with the road if the axle loading of the driven axle is above a set value. A safety valve is fitted which bypasses the manual control valve, for lifting the non driven axle, to prevent it being lifted if the axle loading is above a set value. This prevents suspension damage through inadvertent operation of the lifting control.