Suspension and a dynamic load-compensating fluid spring therefor

A method for supporting a load movable relative to a foundation, wherein the load is dynamically variable in at least one parameter, and wherein the load is held at a predetermined inertial state by an adjustable support extending between and operably connected to the load and the foundation, the method comprising:

• sensing a parameter of at least one of the predetermined inertial state and the load;
• isolating forces applied to the adjustable support by the load from forces applied to the adjustable support by the foundation;
• and
• adjusting the length of the adjustable support to maintain the load in the predetermined inertial state responsive to the sensed parameter of at least one of the predetermined inertial state and the load.

A dynamic load compensator for supporting a dynamic load relative to a foundation at an inertial position independent of the foundation, the dynamic load compensator comprising:

• a support disposed between the load and the foundation, wherein the support is adjustable along at least one axis for movement of the load relative to the foundation;
• a motive force supply to provide an adjustment force to/from the support;
• a controller operably interconnected to the motive force supply and to the support for controlling the amount of motive force applied to/from the support;
• a load sensor operably interconnected to the controller and at least one of the support and the load to detect at least one parameter of the inertial position of the load;
• and
• wherein at least one of the controller and the load sensor isolates the dynamic load from the foundation whereby the support is independently adjustable in response to a force imparted to the support by the foundation and to a force imparted to the load sensor by the load for adjusting the dynamic load relative to the foundation in different manners depending upon whether the force is imparted by the load or by the foundation;
• the support comprises a housing having a hollow interior, the motive force supply comprises a source and accumulator of pressurized fluid, and the controller comprises a valve positioned within the housing, dividing the interior of the housing into a first chamber and a second chamber, and moveable from a neutral position to a first position for admitting fluid into the housing from the source and to a second position for discharging fluid from the housing into the accumulator in response to the sensed parameter of the inertial position and maintain the load at the predetermined inertial position;
• and
• the sensor comprises a pressure accumulator filled with compressible gas and operably connected to the valve wherein the relative force acting on the valve is transferred to the pressure accumulator resulting in a corresponding compression or expansion of the compressible gas, enabling the valve to slide from the neutral position to either the first or second position to equalize the pressure in the first and second chambers and isolating the load from the foundation.

An adjustable support for supporting a dynamic load relative to a foundation at an inertial position independent of the foundation, the adjustable support comprising:

• a housing having a hollow interior and an upper end and an open lower end that provides access to the housing hollow interior;
• a piston having a head and a rod extending from the head, the head being slidably received within the hollow interior of the housing, and the rod extending through the open lower end of the housing and adapted to be operably connected to the foundation;
• a valve slidably mounted within the housing hollow interior above the piston head, forming a fluid tight seal relative to the housing and dividing the interior of the housing into a first fluid chamber above the valve and a second fluid chamber between the valve and the piston head;
• wherein the valve is slidable from a neutral position to a first position for admitting fluid into the second chamber and from the neutral position to a second position for discharging fluid from the second chamber and the first chamber is operably connected to the dynamic load so that any change in the dynamic load correspondingly changes the pressure in the first chamber to move the valve to either one of the first and second positions to admit or release fluid from the second chamber as necessary to equalize the pressure of the second chamber with that of the first chamber and extend or retract the rod from the housing to substantially maintain the dynamic load at its inertial position;
• a fluid supply passage extending between first and second openings in the housing, with the first opening corresponding to the axial position of the valve and the second opening corresponding to the axial position of the piston;
• a fluid relief passage extending between first and second openings in the housing, with the first opening corresponding to the axial position of the valve and the second opening corresponding to the axial position of the piston;
• and
• wherein the piston is moveable from a neutral position where the piston closes both the second openings of the supply and relief passages to a first position where the piston closes the second opening to the relief passage and opens the second opening to the supply passage and a second position where the piston closes the second opening to the supply passage and opens the second opening to the relief passage, wherein fluid is supplied to the second chamber when the valve is in the neutral position and the piston is in the first position and fluid is removed from the second chamber when the valve is in the neutral position and the piston is in the second position.

A method for supporting a load movable relative to a foundation, wherein the load is dynamically variable in at least one parameter, and wherein the load is held at a predetermined inertial state by an adjustable support extending between and operably connected to the load and the foundation, the method comprising:

• providing an adjustable support comprising:
• a housing having a hollow interior and an open upper end and an open lower end that provides access to the housing hollow interior,
• a piston having a head and a rod extending from the head, the head being slidably received within the hollow interior of the housing, and the rod extending through the open lower end of the housing and adapted to be operably connected to the foundation,
• a valve slidably mounted within the housing hollow interior above the piston head, forming a fluid tight seal relative to the housing and dividing the interior of the housing into a first fluid chamber above the valve and a second fluid chamber between the valve and the piston head, and
• a second piston having a head and a rod extending from the head, the head being slidably received within the hollow interior of the housing above the valve, and the rod extending through the open upper end of the housing and adapted to be operably connected to the dynamic load;
• sensing a parameter of at least one of the predetermined inertial state and the load;
• adjusting the adjustable support to maintain the load in the predetermined inertial state responsive to the sensed parameter of at least one of the predetermined inertial state and the load by adding or removing fluid from the second chamber to equalize the pressure of the second chamber with that of the first chamber.

A dynamic load compensator for supporting a dynamic load relative to a foundation at an inertial position independent of the foundation, the dynamic load compensator comprising:

• a support disposed between the load and the foundation and comprising a housing having a hollow interior and a piston having a head and a rod extending from the head, the head being slideably received within the hollow interior of the housing and operably connected to the foundation, wherein the support is adjustable along at least one axis for movement of the load relative to the foundation;
• a motive force supply comprising a source and accumulator of pressurized fluid to provide an adjustment force to/from the support;
• a controller comprising a valve positioned within the housing and defining a fluid chamber, between the valve and the piston head, that is fluidly connected to the source and accumulator, the valve is moveable from a neutral position to a first position to fluidly connect the first chamber to the source for admitting fluid from the source into the fluid chamber, and from the neutral position to a second position to fluidly connect the fluid chamber to the accumulator for discharging fluid from the fluid chamber to control the amount of motive force applied to/from the support;
• a fluid supply passage fluidly connecting the fluid source to the housing near the valve;
• a fluid relief passage fluidly connecting the fluid accumulator to the housing near the valve;
• wherein the valve is moveable from a neutral position where the valve closes both the fluid supply and fluid relief passages to a first position where the valve closes the fluid relief passage and opens the fluid supply passage to introduce fluid on the side of the valve opposite the fluid chamber and a second position where the valve closes the fluid supply passage and opens the fluid relief passage to remove fluid from the fluid chamber;
• the valve has first and second axially spaced channels, the first channel fluidly connects the first fluid supply passage to the fluid source when the valve is in the neutral position and the second channel fluidly connects the fluid relief passage to the accumulator when the valve is in the neutral position;
• a load sensor operably interconnected to the controller and at least one of the support and the load to detect at least one parameter of the inertial position of the load;
• wherein at least one of the controller and the load sensor isolates the dynamic load from the foundation and any force acting on the load or foundation is transferred to the valve through the relative movement of the housing and piston, transferring the force to the valve through the fluid chamber, wherein the valve forms the sensor and the relative movement of the housing and the piston define the sensed parameter, whereby the support is independently adjustable in response to a force imparted to the support by the foundation and to a force imparted to the load sensor by the load to adjust the dynamic load relative to the foundation in different manners depending upon whether the force is imparted on the load or the foundation.

A method for supporting a load movable relative to a foundation, wherein the load is dynamically variable in at least one parameter, and wherein the load is held at a predetermined inertial state by an adjustable support extending between and operably connected to the load and the foundation, the method comprising:

• sensing a parameter of at least one of the predetermined inertial state and the load;
• sensing a reaction force responsive to air pressure acting on one of the load or foundation and the reaction force being capable of changing the at least one sensed parameter of the predetermined inertial state and the load;
• isolating forces applied to the adjustable support by the load from forces applied to the adjustable support by the foundation;
• and
• adjusting the adjustable support to maintain the load in the predetermined inertial state responsive to the sensed parameter of at least one of the predetermined inertial state and the load.

An adjustable support for supporting a dynamic load relative to a foundation at an inertial position independent of the foundation, the adjustable support comprising:

• a housing having a hollow interior and an upper end and an open lower end that provides access to the housing hollow interior;
• a piston having a head and a rod extending from the head, the head being slidably received within the hollow interior of the housing, and the rod extending through the open lower end of the housing and adapted to be operably connected to the foundation;
• a valve slidably mounted within the housing hollow interior above the piston head, forming a fluid tight seal relative to the housing and dividing the interior of the housing into a first fluid chamber above the valve and a second fluid chamber between the valve and the piston head, and the first and second fluid chambers are fluidly isolated relative to each other;
• wherein the valve isolates the load and the foundation such that the pressure in the first fluid chamber corresponds to a force of the load acting on the valve and the pressure in the second fluid chamber corresponds to a force of the foundation acting on the valve and the valve is slidable from a neutral position to a first position for admitting fluid into the second fluid chamber and from the neutral position to a second position for discharging fluid from the second fluid chamber to equalize the pressure of the second chamber with that of the first chamber and thereby extend or retract the rod from the housing to substantially maintain the dynamic load at its inertial position;
• and
• and further comprising a pressure accumulator filled with compressible gas and operably connected to the valve wherein the relative force acting on the valve is transferred to the pressure accumulator resulting in a corresponding compression or expansion of the compressible gas, enabling the valve to slide from the neutral position to either the first or second position to equalize the pressure in the first and second chambers and isolating the load from the foundation.