Separation Fastener Energy Absorbing Retaining Element
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Solution Overview
Problem
Existing separation fastener assemblies are not robust enough and often suffer from high dynamical loads during activation, which can lead to damage or separation of components, particularly the housing accommodating the nut, when the movable element rapidly moves from its restraining to its releasing position.
Innovation Solution
A separation fastener assembly with a sleeve-shaped energy absorbing retaining element that is permanently deformed during activation, allowing for load limiting and secure nut retention, featuring a narrowing or progressively increasing cross section and curvilinear design to absorb energy and reduce the risk of component destruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the movable element rapidly moves from the first position to the second position during activation, then the separation function is achieved, but high dynamical loads are generated that can destroy the housing and separate components
Solution Approach 1:
The energy absorbing portion is pre-configured in the retaining element to absorb dynamical loads before they can damage the housing. This cushioning element is positioned beforehand to intercept and dissipate the energy from the rapidly moving movable element, preventing direct transmission of harmful forces to the housing and components.
Solution Approach 2:
The energy absorbing portion acts as an intermediary between the movable element and the housing. Instead of the movable element directly impacting the housing, the energy absorbing portion intercepts the force, transforms the mechanical energy, and dissipates it, thereby protecting the housing from destruction while still allowing the separation function to occur.
2Speed
If a pyrotechnic charge is used to provide rapid release, then the separation speed is improved, but the dynamical loads on components are increased
Solution Approach 1:
The energy absorbing portion serves as an intermediary that decouples the high-speed separation function from the high-force generation. The pyrotechnic charge provides rapid movement, but the energy absorbing portion intercepts and dissipates the excessive forces, allowing fast separation without proportionally high damaging loads on components.
Solution Approach 2:
The harmful dynamical loads generated by rapid pyrotechnic activation are converted into beneficial energy absorption by the energy absorbing portion. The excessive kinetic energy that would otherwise destroy components is instead captured and dissipated by the energy absorbing portion, transforming a harmful effect into a protective mechanism.
3Device complexity
If the retaining element only holds the nut in place, then the structure is simple, but it cannot limit loads during activation
Solution Approach 1:
The retaining element is designed with multi-functionality, combining both the nut retention function and the load limiting function within a single component. The energy absorbing portion is integrated into the retaining element, allowing it to simultaneously hold the nut in place during normal operation and absorb/dissipate dynamical loads during activation, eliminating the need for separate components.
Solution Approach 2:
The retaining element merges two previously separate functions into one unified component: the structural function of holding the nut and the protective function of limiting loads through energy absorption. This integration simplifies the overall structure while enhancing reliability, as the single retaining element performs both critical roles without requiring additional parts.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The energy absorbing retaining element effectively limits loads on the housing and nut, enhancing the robustness and cost-efficiency of the separation fastener assembly by reducing the risk of damage during rapid movement and activation, while maintaining secure connections.
Implementation Method 1
a retaining element which is arranged to hold the nut in place, wherein the retaining element comprises an energy absorbing portion which is sleeve shaped and adapted to be permanently deformed by the movable element when the movable element is moved from the first position to the second position
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
The present invention relates to a separation fastener assembly comprising a nut (11) having a plurality of nut segments (11a, 11b, 11c, 11d), a movable element (17) which is movable from a first position, in which it restrains the nut segments (11a, 11b, 11c, 11d) from radial expansion, to a second position, in which it permits the nut segments (11a, 11b, 11c, 11d) to radially expand, a bolt (10) having one end coupled to the nut (11), and a retaining element (19) which is arranged to hold the nut (11) in place. The retaining element (19) comprises an energy absorbing portion (20) which is sleeve shaped and adapted to be permanently deformed by the movable element (17) when the movable element is moved from the first position to the second position.