Patent ID: 7841608

Claim:
A pneumatic proportioning system for heavy-duty vehicle air springs comprising: a) heavy-duty vehicle first and second non-steerable non-drive axles, and a third axle; b) an air supply; c) at least a first air spring and a second air spring, said first and second air springs being in fluid communication with said air supply and being used in conjunction with said first axle and said second axle; d) a first height control valve being in fluid communication with said air supply and with said first and second air springs; e) a solenoid valve being in fluid communication with said height control valve and with said second air spring, said solenoid valve exhausting air from the second air spring when the solenoid valve is activated; f) proportioning means being in fluid communication with at least said solenoid valve, said first air spring, and atmosphere, for limiting said exhausting of said air from said second air spring based upon a condition of said first air spring, adapted to proportion loads between said first air spring and said second air spring, in order to increase maneuverability of said heavy-duty vehicle or to increase life of certain components of the heavy-duty vehicle.