Variable height vehicle suspension

Claim 2

A variable height suspension system for a vehicle frame comprising a plurality of wheel mounts on said vehicle frame, means mounting said wheel mounts for movement toward and away from said vehicle frame to vary the vertical height of said vehicle frame with respect to the ground, means urging said wheel mounts away from said vehicle frame for normally maintaining said vehicle frame at design ground clearance, a plurality of fluid cylinders interconnecting said wheel mounts and vehicle frame, means for permitting displacement of fluid from the head end of said cylinders to the rod end for retraction of the pistons within said cylinders in response to a downward applied force to said vehicle frame for lowering said vehicle frame relative to the ground, and means for retaining said pistons in their retracted position to retain said vehicle frame in the lowered position.

Claim 3

The suspension system of claim 1 wherein said means for permitting displacement of the fluid from the head end of said cylinders to the rod end comprises a fluid line extending between the ends of each cylinder.

Claim 4

The suspension system of claim 2 wherein said means for retaining said pistons in their retracted position comprises a mechanical lock which when actuated prevents extension of said pistons.

Claim 5

The suspension system of claim 2 wherein said means for retaining said pistons in their retracted position comprises a mechanical lock means cooperable with the rod of each cylinder when the associated piston is in the retracted position preventing extension thereof.

Claim 6

The suspension system of claim 4 wherein there are a plurality of said projections on each rod, said lock pin being selectively engageable with any one of said projections for retaining said vehicle frame at different elevations.

Claim 7

The suspension system of claim 4 wherein said lock pin is solenoid actuated.

Claim 8

The suspension system of claim 2 further comprising valve means for selectively opening and closing said fluid lines.

Claim 9

The suspension system of claim 7 wherein said means for retaining said pistons in their retracted position comprises a projection on the rod of each cylinder, and a lock pin engageable with said projection when said pistons are in their retracted position to prevent extension thereof, said lock pin being connected to said valve means for operation thereby.

Claim 10

The suspension system of claim 7 further comprising a second fluid line between the ends of each cylinder, said valve means being operative to close said second fluid line upon opening said first mentioned fluid linE and vice versa, said second fluid line when open permitting fluid flow from the rod end of the associated cylinder to the head end for return movement of said vehicle frame by said spring means.

Claim 11

The suspension system of claim 2 wherein said means for retaining the pistons in their retracted position comprises a check valve in each of said fluid lines which only permits fluid flow from the head end of said cylinders to the rod end.

Claim 12

The suspension system of claim 10 further comprising a second fluid line between the ends of each fluid cylinder, and valve means for selectively opening and closing said second fluid lines, said second fluid lines when open permitting fluid flow from the rod end of each cylinder to the head end for return movement of said vehicle frame by said spring means.

Claim 13

The suspension system of claim 10 further comprising a second fluid line between the ends of each cylinder, and valve means in each said second fluid line for selectively permitting fluid flow from the rod end of each cylinder to the head end.

Claim 14

The suspension system of claim 12 further comprising a third fluid line between the ends of each cylinder, and a blow-off valve in each said third line permitting additional flow from the head end of each cylinder to the rod end when excessive pressures are encountered due to shock loads.

Claim 15

The suspension system of claim 1 wherein said wheel mounts comprise road arms pivotally mounted to said vehicle frame, and said means for urging said wheel mounts away from said vehicle frame comprise torsion rods for the pivotal mounts.

Claim 16

The suspension system of claim 1 wherein said wheel mounts comprise road arms pivotally mounted to said vehicle frame, and said means for urging said wheel mounts away from said vehicle frame comprise coil springs between said road arms and vehicle frame.

Claim 17

The suspension system of claim 1 wherein only the corner wheel mounts for said vehicle frame are provided with said cylinders, said means for permitting displacement of fluid from the head end of said cylinders to the rod end for retraction of the pistons within said cylinders, and said means for retaining said pistons in their retracted position to retain said vehicle frame in the lowered position.

Claim 18

The suspension system of claim 1 wherein the downward force is applied to said vehicle frame by accelerating and braking said vehicle frame to cause said vehicle frame to pitch.

Claim 19

A variable height suspension system for a vehicle frame comprising a plurality of wheel mounts on said vehicle frame, means mounting said wheel mounts for movement toward and away from said vehicle frame to vary the vertical height of said vehicle frame with respect to the ground, means urging said wheel mounts away from said vehicle frame for normally maintaining said vehicle frame at design ground clearance, a plurality of fluid cylinders interconnecting said wheel mounts and vehicle frame, a fluid line extending between the ends of each cylinder for permitting displacement of fluid from the head end of said cylinders to the rod end for retraction of the pistons within said cylinders in response to a downward applied force to said vehicle frame for lowering said vehicle frame relative to the ground, a check valve in each said fluid line which only permits fluid flow from the head end of said cylinders to the rod end, a second fluid line between the ends of each cylinder, and valve means in each said second fluid line movable between an open position permitting fluid flow through said second fluid line and a closed position blocking fluid flow through said second fluid line.

Claim 20

A variable height suspension system for a vehicle frame comprising a plurality of wheel mounts on said vehicle frame, means mounting said wheel mounts for movement toward and away from said vehicle frame to vary the vertical height of said vehicle frame with respect to the ground, means urging said wheel mounts away from said vehicle frame for normally maintaining said vehicle frame at design ground clearance, a plurality of fluid cylinders interconnecting said wheel mounts and vehicle frame, a fluid line extending between the ends of each cylinder for permitting displacement of fluid from the head end of said cylinders to the rod end for retraction of the pistons within said cylinders in response to a downward applied force to said vehicle frame for lowering said vehicle frame relative to the ground, a check valve in each said fluid line which only permits fluid flow from the head end of said cylinders to the rod end, a second fluid line between the ends of each cylinder, and valve means in each said second fluid line movable between an open position permitting fluid flow through said second fluid line and a closed position blocking fluid flow through said second fluid line.

Claim 21

The suspension system of claim 18 further comprising mechanical lock means which when actuated assists in retaining said vehicle frame in the lowered position.