Fluid-operated leveling valve systems

In a method of leveling a supported structure against positional variations relative to a supporting structure with a fluid suspension system between said supported structure and said supporting structure, the improvement comprising in combination:

• providing said fluid suspension system with a first fluid leveling valve for adjustment and operation of said supported structure to and at a first level relative to said supporting structure;
• providing said fluid suspension system with a second fluid leveling valve for adjustment and operation of said supported structure to and at an alternative second level relative to said supporting structure;
• supporting said supported structure with fluid pressure;
• alternatively regulating said fluid pressure with said first and second fluid leveling valves;
• sensing said fluid pressure;
• and
• alternating between leveling with said first fluid leveling valve and leveling with said second fluid leveling valve in response to said sensed fluid pressure, including adjusting said supported structure with said first fluid leveling valve to said first level relative to said supporting structure;
• sensing said first level;
• operating said first fluid leveling valve in response to said sensed first level to maintain said first level against positional variations;
• alternatively adjusting said supported structure with said second fluid leveling valve to said second level relative to said supporting structure;
• sensing said second level;
• and
• operating said second fluid leveling valve in response to said sensed second level to maintain said second level against positional variations.

In a method of leveling a supported structure against positional variations relative to a supporting structure with a fluid suspension system between said supported structure and said supporting structure, wherein said supporting structure includes an axle structure of a road vehicle, said supported structure includes a vehicular frame structure supported by said axle structure, and said fluid suspension system is a vehicular fluid suspension system between said vehicular frame structure and said axle structure, the improvement comprising in combination:

• providing said vehicular fluid suspension system with a first fluid leveling valve for adjustment and operation of said supported structure to and at a first ride height of said vehicular frame structure;
• providing said vehicular fluid suspension system with a second fluid leveling valve for adjustment and operation of said supported structure to and at an alternative second ride height of said vehicular frame structure, different from said first ride height;
• sensing pressure in said vehicular fluid suspension system;
• and
• alternating between leveling with said first fluid leveling valve and leveling with said second fluid leveling valve in response to said sensed pressure, including adjusting said vehicular frame structure with said first fluid leveling valve to said first ride height;
• sensing said first ride height;
• operating said first fluid leveling valve in response to the sensed first ride height to maintain said first ride height against positional variations;
• alternatively adjusting said vehicular frame structure with said second fluid leveling valve to said second ride height;
• sensing said second ride height;
• and
• alternatively operating said second fluid leveling valve in response to the sensed second ride height to maintain said second ride height against positional variations.

In apparatus for leveling a supported structure against positional variations relative to a supporting structure with a fluid suspension system between said supported structure and said supporting structure, the improvement comprising in combination:

• said fluid suspension system including between said supported structure and said supporting structure a level sensing lever, a first fluid leveling valve having a first operating rotor connected to said level sensing lever, and a second fluid leveling valve having a second operating rotor connected to said level sensing lever and angularly offset relative to said first operating rotor;
• said fluid suspension system including between said supporting structure and said supported structure a fluid spring structure;
• and
• a fluid path switcher connecting said fluid spring structure selectively to said first fluid leveling valve, and alternatively to said second fluid leveling valve;
• a fluid pressure sensor in said fluid suspension system;
• and
• a fluid path switcher actuator connected between said fluid pressure sensor and said fluid path switcher so that said fluid path switcher selectively connects said fluid spring structure to said first fluid leveling valve, and alternatively to said second fluid leveling valve in response to pressure variations sensed by said fluid pressure sensor.

In apparatus for leveling a vehicular frame structure with a vehicular fluid suspension system relative to an axle structure of a road vehicle against positional variations, the improvement comprising in combination:

• a fluid spring structure, a first fluid leveling valve, a second fluid leveling valve and a ride height sensor in said vehicular fluid suspension system between said vehicular frame structure and said axle structure;
• said first fluid leveling valve and ride height sensor for operation of said vehicular frame structure at a first ride height relative to a road surface against positional variations;
• said second fluid leveling valve and ride height sensor for operation of said vehicular frame structure at a second ride height relative to said road surface against positional variations;
• a fluid path switcher connecting said fluid spring structure selectively to said first fluid leveling valve, and alternatively to said second fluid leveling valve;
• and
• a fluid pressure sensor connected between said fluid spring structure and said fluid path switcher so that said fluid path switcher selectively connects said fluid spring structure to said first fluid leveling valve, and alternatively to said second fluid leveling valve in response to pressure variations sensed by said fluid pressure sensor.

In apparatus for leveling a vehicular frame structure against load variations relative to an axle structure with a fluid suspension system between said vehicular frame structure and said axle structure,

• the improvement comprising in combination:
• said fluid suspension system including between said vehicular frame structure and said axle structure a fluid spring structure, a ride height sensing lever, a first fluid leveling valve having a first operating rotor connected to said ride height sensing lever, and a second fluid leveling valve having a second operating rotor connected to said ride height sensing lever and angularly offset relative to said first operating rotor;
• a fluid path switcher connecting said fluid spring structure selectively to said first fluid leveling valve, and alternatively to said second fluid levling valve;
• and
• a fluid pressure sensor connected between said fluid spring structure and said fluid path switcher so that said fluid path switcher selectively connects said fluid spring structure to said first fluid leveling valve, and alternatively to said second fluid leveling valve in response to pressure variations sensed by said fluid pressure sensor.