Unlocking tail fin assembly for guided projectiles

An apparatus, comprising:

• a projectile;
• an assembly supported on said projectile for rotation relative thereto about an axis approximately parallel to the direction of travel of said projectile, said assembly spinning freely with respect to said projectile in a rotating mode of operation;
• a plurality of fins supported on said assembly;
• and a locking structure cooperating with said projectile and said assembly, said locking structure preventing said assembly from freely rotating in a locking mode of operation and being responsive to a predetermined condition to switch from said locking mode to said rotating mode, and to permit said assembly to spin freely in said rotating mode of operation;
• wherein said assembly includes a first race, wherein said projectile includes a second race;
• including ball bearings disposed in said first race and said second race;
• wherein said assembly rotates relative to said projectile on said ball bearings;
• including a seal which assists in preventing launch gases from contacting said ball bearings;
• and wherein said assembly, in response to said locking structure permitting free spinning, moves relative to said projectile in a direction substantially parallel to the axis of rotation of said assembly from a first axial position to a second axial position, said axial movement disengaging said seal.

An apparatus, comprising:

• a projectile;
• an assembly supported on said projectile for rotation relative thereto about an axis approximately parallel to the direction of travel of said projectile, said assembly spinning freely with respect to said projectile in a rotating mode of operation;
• a plurality of fins supported on said assembly;
• a locking structure cooperating with said projectile and said assembly, said locking structure preventing said assembly from freely rotating in a locking mode of operation and being responsive to a predetermined condition to switch from said locking mode to said rotating mode, and to permit said assembly to spin freely in said rotating mode of operation;
• and a seal which assists in preventing launch gases from contacting at least a portion of said assembly in said locking mode of operation;
• wherein said assembly, in response to said locking structure permitting free spinning, moves relative to said projectile in a direction substantially parallel to the axis of rotation of said assembly from a first axial position to a second axial position, said axial movement disengaging said seal.

A method for minimizing roll of a projectile, comprising:

• rotatably supporting a fin assembly, which includes a plurality of fins, on a projectile for rotation about an axis approximately parallel to the direction of travel of said projectile, said step of rotatably supporting said fin assembly including:
• providing a first race in said fin assembly;
• providing a second race in said projectile;
• providing ball bearings in said first race and said second race;
• and permitting said fin assembly to rotate relative to said projectile on said ball bearings;
• permitting said fin assembly to spin freely relative to said projectile in a rotating mode of operation;
• preventing said fin assembly from rotating in a locking mode of operation, said locking mode occurring before and during the launch of said projectile;
• switching from said locking mode to said rotating mode after the launch of said projectile;
• sealing said fin assembly with respect to said projectile during said locking mode so that launch gases do not contact said ball bearings;
• preventing said fin assembly from moving relative to said projectile in a direction substantially parallel to the axis of rotation of said fin assembly in said locking mode;
• and
• permitting said fin assembly to move relative to said projectile at the start of said rotating mode, in a direction substantially parallel to the axis of rotation of said fin assembly, from a first axial position to a second axial position, said axial movement disengaging said sealing.

A method for minimizing roll of a projectile, comprising:

• rotatably supporting a fin assembly, which includes a plurality of fins, on a projectile for rotation about an axis approximately parallel to the direction of travel of said projectile;
• permitting said fin assembly to spin freely relative to said projectile in a rotating mode of operation;
• preventing said fin assembly from moving relative to said projectile in a direction substantially parallel to the axis of rotation in a locking mode of operation;
• sealing to prevent launch gases from contacting at least a portion of said fin assembly during said locking mode;
• and
• permitting said fin assembly to move relative to said projectile in a direction substantially parallel to the axis of rotation of said fin assembly from a first axial position to a second axial position in response to a predetermined condition, said axial movement disengaging said sealing.

An apparatus, comprising:

• a projectile;
• a member supported on said projectile for movement relative to said projectile;
• and
• a locking structure cooperable with said member and said projectile, said locking structure being operable to prevent said member from moving with respect to said projectile in a locked mode of operation which is effective prior to and during launch of said projectile, and being operable to permit said member to move relative to said projectile in an unlocked mode of operation which is effective after said locked mode, said locking structure including an igniter that is activated by launch gases during the launch of said projectile and that subsequently generates an explosive force which causes said locking structure to effect a switch from said locked mode of operation to said unlocked mode of operation.

A method of operating a locking structure that can selectively implement locked and unlocked modes of operation in which the locking structure respectively prevents and permits movement relative to a projectile of a member movably supported on the projectile, comprising the steps of:

• providing in the locking structure an igniter which is activated by launch gases during a launch of the projectile and which thereafter generates an explosive force;
• maintaining the locking structure in the locked mode of operation prior to generation of the explosive force by the igniter;
• and
• causing the locking structure to effect a switch from the locked mode of operation to the unlocked mode of operation in response to generation by the igniter of the explosive force.

An apparatus comprising:

• a projectile;
• a member;
• a bearing structure supporting said member on said projectile for relative rotational movement about an axis which extends approximately parallel to a direction of travel of said projectile, and for relative axial movement;
• a locking structure operable to prevent said member from moving axially or rotationally with respect to said projectile in a locked mode of operation which is effective prior to and during a launch of said projectile, and operable to permit said member to move relative to said projectile in an unlocked mode of operation which is effective after said locked mode;
• and
• a seal structure operable in said locked mode of operation for effecting a seal between said member and said projectile which prevents launch gases from contacting said bearing structure, wherein when said locking structure effects a switch from said locked mode to said unlocked mode said member moves axially with respect to said projectile in a manner which effects disengagement of said seal.

A method comprising the steps of:

• providing a bearing structure which supports a member on a projectile for rotational and axial movement in relation to an axis that extends approximately parallel to a direction of travel of the projectile;
• releasably locking the member against rotational and axial movement with respect to the projectile during a locked mode of operation which is effective prior to and during a launch of the projectile;
• effecting a seal between the member and the projectile during the locked mode of operation in a manner which prevents launch gases from contacting the bearing structure;
• thereafter switching from the locked mode to an unlocked mode in which the member is permitted to move rotationally and axially with respect to the projectile;
• and
• effecting axial movement of the member relative to the projectile at the beginning of the unlocked mode in a manner which disengages the seal between the member and the projectile.