High dynamic range suspension apparatus with selective fluid pressure communication

An apparatus for use with a suspension fork or shock absorber, the apparatus comprising:

• a spring piston having a first side and a second side;
• a spring tube body comprising a first end and a second end, wherein the spring piston is slidably disposed within the spring tube body to move within the spring tube body over a travel along an axis of reciprocation, wherein the spring piston bounds a primary positive gas spring chamber disposed between the first side of the spring piston and the first end of the spring tube body and wherein the spring piston bounds at least a first portion of a primary negative gas spring chamber disposed between the second side of the spring piston and the second end of the spring tube body;
• a secondary negative gas spring chamber;
• a sealed interface contacting the spring piston and the spring tube body;
• and
• a separator disposed between the secondary negative gas spring chamber and the primary negative gas spring chamber,
• wherein the separator permits fluid pressure communication between the primary negative gas spring chamber and the secondary negative gas spring chamber over a first portion of the travel of the spring piston,
• wherein the separator prevents fluid pressure communication between the primary negative gas spring chamber and the secondary negative gas spring chamber over a second portion of the travel of the spring piston,
• wherein the travel of the spring piston includes an equilibrium point at which a first pressure exerted by the primary positive gas spring chamber on the first side of the spring piston is equal to a second pressure exerted by the primary negative gas spring chamber and the secondary negative gas spring chamber;
• wherein the primary positive gas chamber, primary negative gas chamber and secondary negative gas chamber are filled with a compressible gas;
• and
• wherein the sealed interface prevents fluid communication between the primary positive gas chamber and the primary negative gas chamber at points along the spring piston's travel away from the equilibrium point.