Preload releasing fastener and release system using same
AssigneeSpace Systems/Loral, Inc.
InventorVarouj G. Baghdasarian
Life of this patent
Estimating the term…
Abstract
A preload reducing fastener adapted to be fastened into a system in which includes a release system. The fastener may have an integral collar which is adapted to change shape, as in the case of a shape memory alloy. The application of heat to fastener may deform the collar such that the fastener may move axially in the load direction, thus reducing the preload previously held by the fastener. A preload reducing device including a preload reducing fastener may include an outer case adapted to center and capture a preload reducing fastener. The case may center the fastener in a desired location in a preloaded system, and may also capture the fastener after release of the system.
Claims21
A release apparatus for controlling the deployment of a device by releasably restraining a first member under tension in a first direction to prevent deployment of the device, the release apparatus comprising:
- a tensioning rod, said tensioning rod adapted to restrain said first member along said first direction;
- and
- a preload-reducing fastener fastened to a first end of said tensioning rod, the preload-reducing fastener including:
- a central body;
- and
- a collar around the central body, wherein the collar is made from a shape memory alloy and is transitionable from a first configuration to a second configuration by inducing a phase change in the shape memory alloy through the application of heat to the collar, and wherein:
- in the first configuration:
- the collar is at least partially defined by two frusto-conical surfaces extending away from the central body,
- the collar has a first length along a center axis of the central body, and
- the two frusto-conical surfaces are offset from one another and slope in the same direction;
- and
- in the second configuration:
- the frusto-conical surfaces are flatter than in the first configuration, and
- the collar has a second length along the center axis that is less than the first length.
A preload-reducing fastener, the preload-reducing fastener comprising:
- a central body;
- and
- a collar around the central body, wherein the collar is made from a shape memory alloy and is transitionable from a first configuration to a second configuration by inducing a phase change in the shape memory alloy through the application of heat to the collar, and wherein:
- in the first configuration:
- the collar is at least partially defined by two frusto-conical surfaces extending away from the central body,
- the collar has a first length along a center axis of the central body, and
- the two frusto-conical surfaces are offset from one another and slope in the same direction;
- and
- in the second configuration:
- the frusto-conical surfaces are flatter than in the first configuration, and
- the collar has a second length along the center axis that is less than the first length.
A preload reducing fastener, the preload reducing fastener comprising:
- a collared nut, the collared nut comprising:
- a central body;
- an internally-threaded hole within the central body;
- and
- a collar around the central body, wherein the collar is made from a shape memory alloy and is transitionable from a first configuration to a second configuration by inducing a phase change in the shape memory alloy through the application of heat to the collar, and wherein:
- in the first configuration:
- the collar is at least partially defined by two frusto-conical surfaces extending away from the central body,
- the collar has a first length along a center axis of the central body, and
- the two frusto-conical surfaces are offset from one another and slope in the same direction, and
- in the second configuration:
- the frusto-conical surfaces are flatter than in the first configuration, and
- the collar has a second length along the center axis that is less than the first length.
Dependencies are inferred from the claim text.