Hydraulic suspension systems with hydraulic shock absorbers or dampers are known and commonly used on most vehicles. A shock absorber is a mechanical device designed to smooth out or dampen shock impulses, and dissipate kinetic energy. Shock absorbers, or merely called shocks, are also known as dampers and dashpots. Pneumatic and hydraulic shock absorbers commonly take the form of a cylinder with a sliding piston inside. The cylinder is filled with a liquid (such as hydraulic fluid) or air. Shock absorbers may include cushions and/or springs. The shock absorber's function in the suspension system of a vehicle is to absorb or dissipate energy acting on the vehicle. While shock absorbers may also serve the purpose of limiting excessive suspension movement, their intended main purpose is to dampen spring oscillations. Shock absorbers use valving of oil and gases to absorb excess energy from the springs. Vehicles typically employ both hydraulic shock absorbers and coil springs or torsion bars. In such a suspension system, “shock absorber” typically refers specifically to the hydraulic piston that absorbs and dissipates (i.e. dampens) vibration.
One requirement with hydraulic suspension systems in vehicles is that they require enough ride height, or ground clearance, to dampen or absorb the terrain being traveled over. The ride height of the vehicle, or the ground clearance of the vehicle, may be relatively small for smaller vehicles and vehicles intended to be driven on smooth surfaces like roads. However, with larger vehicles, like trucks and sports utility vehicles (i.e. SUVs), and vehicles that are designed to be driven off road and over uneven terrain, like military vehicles, the ride height or ground clearance required by the suspension system can be much larger.
One problem discovered in association with a large ride height or the required ground clearance of the vehicle could be the transportation or shipment of the vehicles. For example, if the vehicle needs to be shipped in a container, like the cargo unit of a truck, train, boat, airplane or helicopter, the vehicle may not fit into the container because the vehicle is too tall. As such, there is clearly a need to lower the ride height of a vehicle in order to transport the vehicle in a container, like the cargo unit of a truck, train, boat, airplane or helicopter. Another problem associated with a large ride height or large ground clearance of a vehicle is it may not be ideal for traveling on smoother roads where higher speeds and cornering are desired. For example, multi-purpose vehicles like trucks, SUVs, and even military vehicles come standard with large ride heights or large ground clearances in order for the vehicles to maneuver over uneven terrain or off-road purposes. However, these vehicles are also driven on smooth surfaces like roads at high speeds where cornering may be required. In these situations a lower ride height would be ideal but the vehicle's suspension must still function and dampen the forces acting on the vehicle. As such, it is clear that there is a need for such multi-purpose vehicles to have suspension systems that may be lowered while still functioning to dampen forces acting on the vehicle at a lowered position.
One known solution to lowering the ride height of a vehicle for purposes like transportation is to use mechanical struts to lock the vehicle at a lowered position. The problem with this mechanically locked solution is that it does not allow for the vibrations of the container to be dampened by the suspension system, or the hydraulic dampers, as they are locked into place. Thus, the vibrations of the shipping container, whether it be the vibrations of the truck, train, boat, plain or helicopter go directly into the vehicle which has been discovered to cause damage to the vehicle being shipped. In addition, these mechanical struts clearly would not work for lowering the ride height of the multi-purpose vehicles described previously. Other problems with these mechanical struts that lock the vehicle down is that they are difficult to install and take time and power to lower the vehicle. This may not be ideal for some situations, like military transportation, where time and efficiency are of the essence. As such, there is clearly a need to provide a system for lowering the ride height of a vehicle that still provides damping forces to the vehicle while it is lowered and is quick and easy to operate.
The instant invention is designed to address at least some of the above mentioned problems.