Suspension system with enhanced stability

A suspension system for supporting a vehicle chassis having a longitudinal axis, said suspension system comprising:

• a first axle and a second axle wherein each of said first and second axles extend substantially perpendicular to the longitudinal axis;
• a first longitudinal assembly secured relative to both said first axle and said second axle;
• a second longitudinal assembly secured relative to both said first axle and said second axle;
• first and second air springs, said first air spring coupled with said first longitudinal assembly and adapted to transfer forces between said first longitudinal assembly and the vehicle chassis, said second air spring coupled with said second longitudinal assembly and adapted to transfer forces between said second longitudinal assembly and the vehicle chassis;
• first and second lift limiting members, said first lift limiting member being secured relative to the vehicle chassis and said first longitudinal assembly, said second lift limiting member being secured relative to the vehicle chassis and said second longitudinal assembly, and wherein each of said first and second lift limiting members respectively limit vertical separation between said first and second longitudinal assemblies and the vehicle chassis within a respective limited range of vertical separation having a predetermined maximum limit;
• first and second spring members, said first spring member being coupled with said first longitudinal assembly, said second spring member being coupled with said second longitudinal assembly, wherein as said first and second longitudinal assemblies are moved through said respective limited ranges of vertical separation toward said predetermined maximum limits, each of said first and second spring members exert a force respectively urging said first and second longitudinal assemblies away from the vehicle chassis within a respective first biasing region of said respective limited ranges and then each of said first and second spring members exert no biasing force urging said first and second longitudinal assemblies away from the vehicle chassis within a respective second non-biasing region of said respective limited ranges;
• and
• wherein as said first and second longitudinal assemblies are moved through said respective limited ranges of vertical separation within said first biasing regions toward said predetermined maximum limits each of said first and second spring members exerts a spring force at a respective first spring rate in a first spring rate zone and then at a respective second spring rate in a second spring rate zone wherein each of said second spring rates are respectively greater than said first spring rates.

A sliding suspension system for supporting a vehicle chassis having a longitudinal axis, said sliding suspension system comprising:

• a first axle and a second axle wherein each of said first and second axles extend substantially perpendicular to the longitudinal axis;
• first and second longitudinal rails slidably securable to the vehicle chassis on opposite sides of the longitudinal axis;
• a first longitudinal assembly including a longitudinally extending first leaf spring secured relative to both said first axle and said second axle, said first longitudinal assembly being positioned below and supported by said first longitudinal rail;
• a second longitudinal assembly including a longitudinally extending second leaf spring secured relative to both said first axle and said second axle, said second longitudinal assembly being positioned below and supported by said second longitudinal rail;
• first and second air springs, said first air spring coupled with said first longitudinal assembly and adapted to transfer forces between said first longitudinal assembly and said first rail, said second air spring coupled with said second longitudinal assembly and adapted to transfer forces between said second longitudinal assembly and said second rail;
• first and second lift limiting members, said first lift limiting member being secured relative to said first longitudinal assembly and said first rail, said second lift limiting member being secured relative to said second longitudinal assembly and said second rail, and wherein each of said first and second lift limiting members respectively limit vertical separation between said first and second longitudinal assemblies and the vehicle chassis within a respective limited range of vertical separation having a predetermined maximum limit;
• first and second spring members, said first spring member being coupled with said first longitudinal assembly, said second spring member being coupled with said second longitudinal assembly, wherein as said first and second longitudinal assemblies are moved through said respective limited ranges of vertical separation toward said predetermined maximum limits, each of said first and second spring members exert a force respectively urging said first and second longitudinal assemblies away from the vehicle chassis within a respective first biasing region of said respective limited ranges and then each of said first and second spring members exert no biasing force urging said first and second longitudinal assemblies away from the vehicle chassis within a respective second non-biasing region of said respective limited ranges;
• and
• wherein as said first and second longitudinal assemblies are moved through said respective limited ranges of vertical separation within said first biasing regions toward said predetermined maximum limits each of said first and second spring members exerts a spring force at a respective first spring rate in a first spring rate zone and then at a respective second spring rate in a second spring rate zone wherein each of said second spring rates are respectively greater than said first spring rates;
• and
• wherein said first and second rails, said first and second longitudinal assemblies, said first and second axles, said first and second air springs and said first and second spring members are longitudinally selectively slidable as a unit relative to the vehicle chassis.