Contracting landing gear shock strut

In an aircraft landing gear assembly, a shock absorber comprising:

• first and second generally tubular members positioned telescopically with respect to each other;
• a floating member carried by and axially slidable with respect to said first tubular member;
• said first and second tubular members and said floating member defining a first pressure chamber, a reserve chamber, and a second pressure chamber;
• passageway means for providing a metered hydraulic orifice area between the reserve chamber and the first pressure chamber;
• and
• stop means carried by said second tubular member for engaging said floating member and sliding said floating member relative to said first tubular member, when said tubular members retract relative to each other beyond a predetermined position, to reduce the volume of the second pressure chamber;
• said shock absorber having a first mode of operation in which the volume of the reserve chamber decreases and the volume of the second pressure chamber remains essentially constant as said tubular members retract relative to each other toward said predetermined position, and a second mode of operation in which the volume of the second pressure chamber decreases as said tubular members retract relative to each other beyond said predetermined position;
• in which said second tubular member carries a fixed generally radially extending wall that defines said orifice area, said first tubular member carries a fixed radial wall that defines a first radial wall of the second pressure chamber;
• and the floating member includes a metering pin, and a radial wall that defines a second opposite radial wall of the second pressure chamber.

In combination:

• in an aircraft landing gear assembly, a shock absorber comprising first and second generally tubular members positioned telescopically with respect to each other;
• a floating member carried by and axially slidable with respect to said first tubular member;
• said first and second tubular members and said floating member defining a first pressure chamber, a reserve chamber, and a second pressure chamber;
• passageway means for providing a metered hydraulic orifice area between the reserve chamber and the first pressure chamber;
• and stop means carried by said second tubular member for engaging said floating member and sliding said floating member relative to said first tubular member, when said tubular members retract relative to each other beyond a predetermined position, to reduce the volume of the second pressure chamber;
• said shock absorber having a first mode of operation in which the volume of the reserve chamber decreases and the volume of the second pressure chamber remains essentially constant as said tubular members retract relative to each other toward said predetermined position, and a second mode of operation in which the volume of the second pressure chamber decreases as said tubular members retract relative to each other beyond said predetermined position;
• aircraft landing gear support structure to which one of said tubular members is pivotably attached;
• and
• means for pivoting the shock absorber into a stowed position relative to said support structure and for shortening the shock absorber, as it is being pivoted, by retracting said tubular members relative to each other substantially to said predetermined position;
• in which said second tubular member carries a fixed generally radially extending wall that defines said orifice area;
• said first tubular member carries a fixed radial wall that defines a first radial wall of the second pressure chamber;
• and the floating member includes a metering pin, and a radial wall that defines a second opposite radial wall of the second pressure chamber.

In combination:

• in an aircraft landing gear assembly, a shock absorber comprising first and second generally tubular members positioned telescopically with respect to each other;
• a floating member carried by and axially slidable with respect to said first tubular member;
• said first and second tubular members and said floating member defining a first pressure chamber, a reserve chamber, and a second pressure chamber;
• passageway means for providing a metered hydraulic orifice area between the reserve chamber and the first pressure chamber;
• and stop means carried by said second tubular member for engaging said floating member and sliding said floating member relative to said first tubular member, when said tubular members retract relative to each other beyond a predetermined position, to reduce the volume of the second pressure chamber;
• said shock absorber having a first mode of operation in which the volume of the reserve chamber decreases and the volume of the second pressure chamber remains essentially constant as said tubular members retract relative to each other toward said predetermined position, and a second mode of operation in which the volume of the second pressure chamber decreases as said tubular members retract relative to each other beyond said predetermined position;
• aircraft landing gear support structure to which one of said tubular members is pivotably attached;
• and
• means for pivoting the shock absorber into a stowed position relative to said support structure and for shortening the shock absorber, as it is being pivoted, by retracting said tubular members relative to each other substantially to said predetermined position;
• in which said second tubular member is pivotably attached to said support structure and carries a fixed generally radially extending wall that defines said orifice area, said first tubular member carries a fixed radial wall that defines a bottom radial wall of the second pressure chamber;
• and the floating member includes a metering pin, and a radial wall that defines an opposite top radial wall of the second pressure chamber.

In combination:

• in an aircraft landing gear assembly, a shock absorber comprising first and second generally tubular members positioned telescopically with respect to each other;
• a floating member carried by and axially slidable with respect to said first tubular member;
• said first and second tubular members and said floating member defining a first pressure chamber, a reserve chamber, and a second pressure chamber;
• passageway means for providing a metered hydraulic orifice area between the reserve chamber and the first pressure chamber;
• and stop means carried by said second tubular member for engaging said floating member and sliding said floating member relative to said first tubular member, when said tubular members retract relative to each other beyond a predetermined position, to reduce the volume of the second pressure chamber;
• said shock absorber having a first mode of operation in which the volume of the reserve chamber decreases and the volume of the second pressure chamber remains essentially constant as said tubular members retract relative to each other toward said predetermined position, and a second mode of operation in which the volume of the second pressure chamber decreases as said tubular members retract relative to each other beyond said predetermined position;
• aircraft landing gear support structure to which one of said tubular members is pivotably attached;
• and
• means for pivoting the shock absorber into a stowed position relative to said support structure and for shortening the shock absorber, as it is being pivoted, by retracting said tubular members relative to each other substantially to said predetermined position;
• in which said second tubular member carries a fixed metering pin;
• said first tubular member carries a radial wall that defines a first radial wall of the second pressure chamber;
• and the floating member includes a generally radially extending wall that defines said orifice area, and a radial wall that defines a second opposite radial wall of the second pressure chamber.

A method for absorbing landing and taxiing shocks of an aircraft, comprising:

• providing first and second generally tubular members positioned telescopically with respect to each other and having a first pressure chamber and a second pressure chamber;
• pressurizing the first and second pressure chambers to create first and second gas cushions, respectively, with first and second maximum pressures, respectively, and first and second minimum pressures, respectively;
• said first maximum pressure being less than said second minimum pressure;
• while the aircraft is in flight, pivoting said tubular members into a landing position, and substantially fully extending said tubular members with respect to each other;
• landing the aircraft, and applying the compressive force of landing and taxiing shocks to said tubular members to cause them to retract relative to each other to a predetermined position;
• while said tubular members are so retracting, allowing their retraction to compress the first gas cushion and maintaining the volume of the second gas cushion essentially constant;
• when said tubular members reach said predetermined position, allowing said compressive force to cause them to retract relative to each other beyond said predetermined position;
• and
• while said tubular members are retracting beyond said predetermined position, allowing their retraction to compress the second gas cushion.

A method for absorbing landing and taxiing shocks of an aircraft, comprising:

• providing first and second generally tubular members positioned telescopically with respect to each other and having a first pressure chamber and a second pressure chamber;
• pressurizing the first and second pressure chambers to create first and second gas cushions, respectively, with first and second maximum pressures, respectively, and first and second minimum pressures, respectively;
• said first maximum pressure being less than said second minimum pressure;
• while the aircraft is in flight, pivoting said tubular members into a landing position, and substantially fully extending said tubular members with respect to each other;
• landing the aircraft, and applying the compressive force of landing and taxiing shocks to said tubular members to cause them to retract relative to each other to a predetermined position;
• while said tubular members are so retracting, allowing their retraction to compress the first gas cushion and maintaining the volume of the second gas cushion essentially constant;
• when said tubular members reach said predetermined position, allowing said compressive force to cause them to retract relative to each other beyond said predetermined position;
• while said tubular members are retracting beyond said predetermined position, allowing their retraction to compress the second gas cushion;
• and
• accomplishing a takeoff of the aircraft with said members in said landing position;
• and then pivoting said members from said landing position into a stowed position, and as said members are pivoting, retracting said members relative to each other substantially to said predetermined position and maintaining the volume of the second gas cushion essentially constant.