Ballistic tolerant hydraulic control actuator and method of fabricating same
First Claim
1. An hydraulic actuator comprising:
- (A) a movable member,(B) a hybrid housing enveloping said movable member and cooperating therewith to define at least one hydraulic actuating fluid chamber so that the movable member is movable with respect to the housing in response to hydraulic pressure in said chamber and including;
(1) an outer wall of selected material and wall thickness "t" to satisfy actuator fatigue requirements,(2) a central sleeve of selected material snugly fitted into said outer wall and being of selected wall thickness, and,(3) an inner wall of selected wall thickness snugly sleeved into said central sleeve and being of selected hardness to be wear resistant to the wear of said movable member within said housing, and so that impacting or impacting and penetrating of the outer wall by a threat projectile of diameter D generates stress waves therein of sufficient intensity to be imparted therefrom into the central sleeve to locally disintegrate and clear the central sleeve portion in the area of projectile impact, and further so that said inner wall is of selected fracture toughness strength, thickness, and residual stress so as to be cleared together with said cleared central sleeve portion, and still further so that projectile diameter D forms a ratio t/D with outer wall thickness t closer to 1/3 than any other threat projectile, and so that petals formed in the outer wall by the projectile passing therethrough are of less depth than the combined wall thickness of said central sleeve and said inner wall and will occupy a void left by said locally cleared central sleeve and inner wall portions, so that said movable member may move within said housing following such projectile damage, and(4) means to actuate said movable member within said housing following the occurance of such projectile damage.
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Abstract
A ballistic tolerant control actuator of the hydraulic cylinder-piston type and having a hybrid housing comprising a structural outer wall of selected characteristics and wall thickness "t", a central sleeve snuggly fitted within the outer wall and being of selected characteristics and selected wall thickness so that when the outer wall is impacted and/or penetrated by a projectile of diameter D, impact induced stress waves from the outer wall pass into the central sleeve with sufficient intensity to locally disintegrate and clear the central sleeve in the vicinity of the projectile impact, and so that the petals formed in the outer wall will not project farther radially inwardly than the petals which would be formed in the most critical case by a projectile whose diameter D produced the ratio t/D=1/3. The hybrid housing also includes an inner wall snuggly fitted within the central sleeve and being of selected characteristics such that the portion thereof adjacent the cleared central sleeve portion will be cleared therewith and so that any petals ballistically formed therein will be easily cleared by piston motion.
36 Citations
26 Claims
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1. An hydraulic actuator comprising:
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(A) a movable member, (B) a hybrid housing enveloping said movable member and cooperating therewith to define at least one hydraulic actuating fluid chamber so that the movable member is movable with respect to the housing in response to hydraulic pressure in said chamber and including; (1) an outer wall of selected material and wall thickness "t" to satisfy actuator fatigue requirements, (2) a central sleeve of selected material snugly fitted into said outer wall and being of selected wall thickness, and, (3) an inner wall of selected wall thickness snugly sleeved into said central sleeve and being of selected hardness to be wear resistant to the wear of said movable member within said housing, and so that impacting or impacting and penetrating of the outer wall by a threat projectile of diameter D generates stress waves therein of sufficient intensity to be imparted therefrom into the central sleeve to locally disintegrate and clear the central sleeve portion in the area of projectile impact, and further so that said inner wall is of selected fracture toughness strength, thickness, and residual stress so as to be cleared together with said cleared central sleeve portion, and still further so that projectile diameter D forms a ratio t/D with outer wall thickness t closer to 1/3 than any other threat projectile, and so that petals formed in the outer wall by the projectile passing therethrough are of less depth than the combined wall thickness of said central sleeve and said inner wall and will occupy a void left by said locally cleared central sleeve and inner wall portions, so that said movable member may move within said housing following such projectile damage, and (4) means to actuate said movable member within said housing following the occurance of such projectile damage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A hydraulic actuator comprising:
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(A) a movable member positioned within a housing and cooperating therewith to define at least one pressure chamber to receive hydraulic fluid to actuate the movable member within the housing, (B) wherein said housing comprises; (1) an outer wall of selected thickness t to satisfy actuator fatigue requirements, (2) a central sleeve snugly sleeved into said outer wall and being of selected structural characteristics so that shock waves generated in said outer wall due to projectile impact and penetration are imparted to said central sleeve with sufficient intensity to locally disintegrate and clear said sleeve, and so that thickness of the central sleeve is at least equal to the depth of petals formed in the outer wall by a threat projectile of diameter D impacting, penetrating, and passing therethrough, and which threat projectile forms a ratio t/D nearer to 1/3 than any other threat projectile, (C) means to actuate said movable member within said housing following the occurance of such projectile damage, (D) means to provide a wear resistant and protective layer to the central sleeve inner surface without preventing actuation of said movable member within said housing following the occurance of such projectile damage.
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24. A hydraulic actuator comprising:
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(A) a movable member positioned within a hybrid housing and cooperating therewith to define at least one pressure chamber to receive hydraulic fluid to actuate the movable member within the housing, (B) wherein said hybrid housing comprises; (1) an outer steel wall of selected thickness t to satisfy actuator fatigue requirements, (2) a central sleeve of bonded graphite laminates snugly sleeved into and bonded to said outer wall and being of selected structural characteristics so that stress waves generated in said outer wall due to projectile impact and penetration are imparted to said central sleeve with sufficient intensity to locally disintegrate and clear said sleeve, and so that the thickness of the central sleeve is at least equal to the depth of petals formed in the outer wall by a projectile, and wherein the wall thickness of the central sleeve is greater than the maximum petal depth formed in the outer wall by projectile impact and penetration of the threat projectile having a diameter D which forms a ratio t/D with outer wall thickness t closer to 1/3 than any other threat projectile, (3) an inner wall of electroformed nickel sleeved into and bonded to the central sleeve so as to be cleared with the central sleeve and so that ballistically induced stress waves reflected therefrom also serve to clear the inner wall and central sleeve and weaken any petals left in the inner wall. - View Dependent Claims (25)
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26. The method of producing a ballistically tolerant hydraulic servo cylinder capable of having a projectile of diameter D pass therethrough so that the nature of the ballistic damage caused thereby will permit continued movement of the servo movable member within the cylinder, comprising the steps of:
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(A) fabricating from a material having low residual stress a wear resistant inner wall of wall thickness about 0.030 inches or less and of a selected inner diameter required to permit the servo to perform its required function, (B) producing an outer wall of selected wall thickness t which will carry the necessary loads without fatigue failure to permit the servo to perform its required function, and made of selected material so that the impacting, penetrating, and passing therethrough of a projectile of diameter D will set up stress waves therein to be transmitted therethrough and so that petals will be formed therein of selected maximum petal depth no greater than the petal depth experienced from the threat projectile producing the ratio t/D closest to 1/3, and (C) producing a central sleeve member of material having low tensile strength in a radially inward direction so as to clear when subjected to stress waves imparted thereto from the outer housing and reflected therethrough from the inner wall, and having a wall thickness of at least the outer wall maximum petal depth, and (D) sleeving the central sleeve between the inner and outer walls in snug fit relationship so that the central sleeve is in radial compression and bonding it to each wall.
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Specification