Composite rod

Claim 2

A composite rod comprising: an elongated outer rod section having a cavity therein extending generally axially of the outer rod section, said outer rod section being subjected to a substantial axial tensile force of a first predetermined magnitude whereby said outer rod section is elongated a first predetermined amount per unit of force applied thereto; a compressive element in said cavity, said element being supported by said outer rod section and being subjected to an axial compressive force of a second predetermined magnitude whereby the element is axially shortened a second predetermined amount per said unit of force applied thereto, said first predetermined amount being greater than said second predetermined amount whereby placing an axial load on the composite rod results in a relatively small change of length of said outer rod section to thereby reduce fatigue; and at least a portion of said element beinG in particulate form.

Claim 3

A composite rod as defined in claim 1 wherein said element is of less density than said outer rod section.

Claim 4

A composite rod comprising: an outer rod section having a cavity therein, said outer rod section having an abutment in said cavity; an inner rod section in said cavity supportable against said abutment; a stressing member drivingly connectible to said outer rod section to load said inner rod section in compression between said member and said abutment and to apply a tensile force to said outer rod section; said inner rod section being constructed of a material having a higher modulus of elasticity than the material of said outer rod section, the density of said inner rod section being no greater than the density of the outer rod section; and a piston on said outer rod section.

Claim 5

A composite rod comprising: an outer rod section having a cavity therein, said outer rod section having an abutment in said cavity; an inner rod section in said cavity supportable against said abutment; a stressing member drivingly connectible to said outer rod section to load said inner rod section in compression between said member and said abutment and to apply a tensile force to said outer rod section; said inner rod section being constructed of a material having a higher modulus of elasticity than the material of said outer rod section, the density of said inner rod section being no greater than the density of the outer rod section; and a piston on said outer rod section.

Claim 6

A composite rod as defined in claim 3 wherein said abutment is a first abutment, said outer rod section having a second abutment in said cavity spaced axially along said inner rod section, said inner rod section being supportable against said first and second abutments, said stressing member also holding said inner rod section in compression between said abutments.

Claim 7

A composite rod comprising: an outer rod section having a cavity therein, said outer rod section having an abutment in said cavity; an inner rod section in said cavity supportable against said abutment; a stressing member drivingly connectible to said outer rod section to load said inner rod section in compression between said member and said abutment and to apply a tensile force to said outer rod section; said inner rod section being constructed of a material having a higher modulus of elasticity than the material of said outer rod section, the density of said inner rod section being no greater than the density of the outer rod section; and said outer rod section being constructed of steel and said inner rod section being constructed of beryllium, said outer rod section having means adjacent one end thereof for attachment to external structure, said stressing member and said outer rod section being threadedly attached, said stressing member having means for attachment to external structure, the cross sectional area of the outer rod being less than the cross sectional area of the inner rod.

Claim 8

A composite rod comprising: an outer rod section having a cavity therein, said outer rod section having an abutment in said cavity; an inner rod section in said cavity supportable against said abutment; a stressing member drivingly connectible to said outer rod section to load said inner rod section in compression between said member and said abutment and to apply a tensile force to said outer rod section; said inner rod section being constructed of a material having a higher modulus of elasticity than the material of said outer rod section, the density of said inner rod section being no greater than the density of the outer rod section; and said outer rod section being constructed of steel and said inner rod section being constructed of beryllium, said outer rod section having means adjacent one end thereof for attachment to external structure, said stressing member and said outer rod section being threadedly attached, said stressing member having means for attachment to external structure, the cross sectional area of the outer rod being less than the cross sectional area of the inner rod.

Claim 9

An actuator for driving a driven element comprising: a housing; a piston slidable in said housing; a composite actuator rod at least partially receivable in said housing, said composite actuator rod including an inner rod section and an outer rod section substantially surrounding the inner rod section, said outer rod section having an abutment against which the inner rod section is supportable and means connectible to the outer rod section for loading said inner rod section generally axially in compression and for loading said outer rod section generally axially in tension; means for mounting said piston on said composite actuator rod, said composite actuator rod being connectible to said driven element; and port means in said housing for admitting fluid under pressure to at least one side of said piston to thereby drive the latter and the composite actuator rod.

Claim 10

An actuator for driving a driven element comprising: a housing; a piston slidable in said housing; a composite actuator rod at least partially receivable in said housing, said composite actuator rod including an inner rod section and an outer rod section substantially surrounding the inner rod section, said outer rod section having an abutment against which the inner rod section is supportable and means connectible to the outer rod section for loading said inner rod section generally axially in compression and for loading said outer rod section generally axially in tension; means for mounting said piston on said composite actuator rod, said composite actuator rod being connectible to said driven element; and port means in said housing for admitting fluid under pressure to at least one side of said piston to thereby drive the latter and the composite actuator rod.

Claim 11

An actuator as defined in claim 6 wherein said outer rod section and said inner rod section consist essentially of first and second materials, respectively, said first material having a greater density than said second material, said inner rod section being stiffer than said outer rod section.

Claim 12

An actuator as defined in claim 7 wherein the modulus of elasticity of said second material is greater than the modulus of elasticity of said first material.

Claim 13

An actuator as defined in claim 6 wherein said piston is a first piston and said abutment is a first abutment, said actuator including a second piston and means for mounting said second piston on said outer rod section in axially spaced relationship to said first piston, said outer rod section inCluding a second abutment, said inner rod section being supportable against said abutments, said first and second abutments being adjacent said first and second pistons, respectively.

Claim 14

A composite rod comprising: an outer member having a cavity therein, said outer member being of a predetermined stiffness, said outer member being attachable to external structure at first and second spaced locations, said cavity lying at least in part between said locations; an inner member in said cavity, said inner member being of greater than said predetermined stiffness; means for preloading the inner member in compression along a first axis which extends generally between said first and second spaced locations; means for preloading the outer member in tension substantially along said first axis, said members being drivingly associated so that placing an external tensile force on the outer member reduces the compressive preload on the inner member; and said outer member being constructed in substantial part of a ferrous metal and said inner member being constructed in substantial part of a material having a higher modulus of elasticity and a lower density than said ferrous metal.

Claim 15

A composite rod comprising: an outer member having a cavity therein, said outer member being of a predetermined stiffness, said outer member being attachable to external structure at first and second spaced locations, said cavity lying at least in part between said locations; an inner member in said cavity, said inner member being of greater than said predetermined stiffness; means for preloading the inner member in compression along a first axis which extends generally between said first and second spaced locations; means for preloading the outer member in tension substantially along said first axis, said members being drivingly associated so that placing an external tensile force on the outer member reduces the compressive preload on the inner member; and said outer member being constructed in substantial part of a ferrous metal and said inner member being constructed in substantial part of a material having a higher modulus of elasticity and a lower density than said ferrous metal.

Claim 16

A composite rod as defined in claim 10 wherein said material is beryllium.

Claim 17

A composite rod as defined in claim 10 wherein said material is boron-carbide.

Claim 18

A stiff composite rod for transmitting force with a minimum deflection of said composite rod, said composite rod comprising: an elongated tubular rod constructed in substantial part of a ferrous metal; an elongated inner rod within said tubular rod member; means coupled to said tubular rod and engageable with said inner rod for applying a compressive preload to said inner rod and a tensile preload to said tubular rod; and said inner rod having a higher modulus of elasticity than said ferrous metal.

Claim 19

A stiff composite rod for transmitting force with a minimum deflection of said composite rod, said composite rod comprising: an elongated tubular rod constructed in substantial part of a ferrous metal; an elongated inner rod within said tubular rod member; means coupled to said tubular rod and engageable with said inner rod for applying a compressive preload to said inner rod and a tensile preload to said tubular rod; and said inner rod having a higher modulus of elasticity than said ferrous metal.