Method and apparatus for minimizing axial friction forces in a cylinder-piston shock absorber

Claim 2

In a shock absorber assembly including a circular cylinder member and a piston member disposed for axial reciprocation in said cylinder member, the combination with said cylinder and piston members comprising: bearing means of annular configuration disposed coaxially with and radially between said cylinder and piston members for supportively guiding the axial reciprocation of said piston member, said bearing means being formed and mounted for rotation about its axis relative to said members; and actuator means connected between said bearing means and at least one of said members for rotating said bearing means relative thereto.

Claim 3

The combination set forth in claim 1, wherein the shock absorber assembly further includes torque linkage means interconnecting said members for preventing relative rotation while permitting axial reciprocation therebetween, and wherein said actuator means includes relatively movable portions, one of said actuator portions being connected to said cylinder member and the other of said actuator portions being connected to said bearing means such that relative movement of said portions effects said rotation of said bearing means relative to both said cylinder member and said piston member.

Claim 4

The combination set forth in claim 2, wherein said movable portions of said actuator means are disposed for relative rectilinear reciprocation, and said actuator means includes means pivotally connecting said portions to said cylinder member and piston member respectively so as to translate said rectilinear reciprocation into oscillatory rotation of said bearing means.

Claim 5

The combination set forth in claim 1, wherein said bearing means includes first and second axially spaced apart ring shaped sections, said first section being rotatably mounted on and axially fixed to said piston member adjacent one end thereof and being axially and circumferentially slidably engaged with an interior wall of said cylinder member, said second bearing section being rotatably mounted on and axially fixed to said cylinder member adjacent one end thereof and being axially and circumferentially slidably engaged with an exterior wall of said piston member, torque coupling means interconnecting said first and second bearing sections for preventing rotation therebetween while permitting relative axial reciprocation therebetween, and said actuator means being connected to one of said bearing sections.

Claim 6

The combination set forth in claim 4, wherein said torque coupling means comprises: an extention sleeve on each of said first and second sections, each said sleeve being oriented to project coaxially toward the other said sleeve, a tubular coupling member coaxially disposed between said exterior wall of said piston member and said interior wall of said cylinder member and axially bridging said sleeves, and axially oriented spline means interconnecting said coupling member and said sleeves.

Claim 7

The combination set forth in claim 4, wherein said actuator means includes an annular crank sleeve rotatably mounted in coaxial relationship with said cylinder member adjacent the end thereof at which said second bearing section is mounted, said crank sleeve having a radially outwardly extending crank arm and means connecting said crank arm to said actuator means for rotating said crank sleeve.

Claim 8

In an aircraft load measurement system of the type including a landing gear shock strut having a circular cylinder member, a piston member mounted for axial reciprocation in said cylinder member and cooperating therewith to define a variable volume fluid confining pressure chamber therebetween, a fluid within such chamber having a pressure representative of a load on said strut, and means for measuring said fluid pressure, the combination therewith comprising: annular bearing means coaxially disposed between said cylinder and piston members for axially guiding the reciprocation of said piston member within said cylinder member, said bearing means being formed and mounted for rotation about its axis relative to said members; and actuator means connected between said bearing means and at least one of said members for rotating said bearing means relative to said members during measurement of said fluid pressure, thereby minimizing axial friction effects between said piston and cylinder members so that the pressure of said fluid substantially equals the load on said strut.

Claim 9

In an aircraft load measurement system of the type including a landing gear shock strut having a circular cylinder member, a piston member mounted for axial reciprocation in said cylinder member and cooperating therewith to define a variable volume fluid confining pressure chamber therebetween, a fluid within such chamber having a pressure representative of a load on said strut, and means for measuring said fluid pressure, the combination therewith comprising: annular bearing means coaxially disposed between said cylinder and piston members for axially guiding the reciprocation of said piston member within said cylinder member, said bearing means being formed and mounted for rotation about its axis relative to said members; and actuator means connected between said bearing means and at least one of said members for rotating said bearing means relative to said members during measurement of said fluid pressure, thereby minimizing axial friction effects between said piston and cylinder members so that the pressure of said fluid substantially equals the load on said strut.

Claim 10

The combination set forth in claim 7, wherein the load measurement system further includes torque linkage means interconnecting said cylinder and piston members preventing relative rotation therebetween, and wherein said actuator means includes first and second portions that are moved relative to each other during operation of said actuator means, means connecting said first portion to said cylinder member and said second portion to said bearing means so as to rotate said bearing means relative to said cylinder member in response to the relative motion of said portions, whereby such rotation relative to said cylinder member also effects rotation of said bearing means relative to said piston member.

Claim 11

An aircraft load measurement apparatus comprising a landing gear shock strut for supporting an aircraft on the ground and including a cylinder member and a piston member disposed for axial reciprocation in said cylinder member forming a variable volume fluid pressure chamber between said members, a fluid within said chamber subject to a compressive load on said strut and having a pressure representative of such load means for measuring said fluid pressure, and means for reducing axial friction forces between said piston member and cylinder member comprising an annular bearing means disposed coaxially with and radially between said cylinder and piston members for guiding axial reciprocation therebetween, said bearing means being disposed for rotation about its axis relative to said members, and actuator means mounted on said shock strut for rotating said bearing means relative to said piston and cylinder members during such pressure measurement.

Claim 12

An aircraft load measurement apparatus comprising a landing gear shock strut for supporting an aircraft on the ground and including a cylinder member and a piston member disposed for axial reciprocation in said cylinder member forming a variable volume fluid pressure chamber between said members, a fluid within said chamber subject to a compressive load on said strut and having a pressure representative of such load means for measuring said fluid pressure, and means for reducing axial friction forces between said piston member and cylinder member comprising an annular bearing means disposed coaxially with and radially between said cylinder and piston members for guiding axial reciprocation therebetween, said bearing means being disposed for rotation about its axis relative to said members, and actuator means mounted on said shock strut for rotating said bearing means relative to said piston and cylinder members during such pressure measurement.

Claim 13

In a method of determining the weight supported by an aircraft landing gear shock strut, including the steps of measuring the pressure of a fluid within a variable volume chamber defined between a shock strut cylinder and cooperating axially reciprocating piston wherein such piston is reciprocatively guided by an annular bearing structure disposed coaxially between the piston and cylinder, and concurrently reducing axially oriented friction forces between the piston and cylinder, the improvement in said step of reducing friction forces comprising rotating the bearing structure about its axis and relative to said piston and cylinder.

Claim 14

In a method of determining the weight supported by an aircraft landing gear shock strut, including the steps of measuring the pressure of a fluid within a variable volume chamber defined between a shock strut cylinder and cooperating axially reciprocating piston wherein such piston is reciprocatively guided by an annular bearing structure disposed coaxially between the piston and cylinder, and concurrently reducing axially oriented friction forces between the piston and cylinder, the improvement in said step of reducing friction forces comprising rotating the bearing structure about its axis and relative to said piston and cylinder.