Fastener Sleeve and Spring Biasing for Preload and Disassembly
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Solution Overview
Problem
Structural joints require reliable preload and easy disassembly, but existing solutions using springs under fastener heads compromise joint integrity and fail to consistently maintain preload.
Innovation Solution
A biasing system comprising sleeves and a spring, where the sleeves form a primary load path for preload and the spring forms a secondary load path to facilitate easy disassembly by biasing the fastener away from the component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If springs are placed under fastener heads to assist removal, then ease of operation is improved, but reliability of joint preload is worsened
Solution Approach 1:
The system divides the fastening function into two separate components: the fastener itself (which provides structural preload through threads) and the spring mechanism (which provides extraction force). This segmentation allows each component to perform its specialized function without compromising the other, resolving the contradiction between maintaining reliable preload and enabling easy disassembly.
Solution Approach 2:
The spring acts as an intermediary element that mediates between the fastener and the workpiece. It provides the necessary extraction force to overcome friction and loading effects during disassembly, while not interfering with the fastener's ability to maintain joint preload during assembly and operation.
2Strength
If fasteners are subjected to loading that inhibits removal, then joint strength is improved, but ease of operation is worsened
Solution Approach 1:
The spring serves as a mediator that counteracts the friction and loading forces that inhibit fastener removal. By providing a continuous extraction force, it enables easy removal even when the joint is subjected to high loads, without compromising the joint strength during operation.
Solution Approach 2:
The spring provides a counteracting force that opposes the friction and loading forces resisting fastener removal. This counterforce mechanism allows the fastener to be easily extracted despite the high joint strength and loading conditions.
3Ease of operation
If springs are used under fastener heads, then ease of disassembly is improved, but manufacturing complexity is worsened
Solution Approach 1:
The spring mechanism is designed to be universally applicable to various fastener types and joint configurations. The standardized spring design can be used across different applications, reducing overall system complexity despite adding the disassembly assistance function.
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
Ensures consistent preload and easy disassembly of structural joints without compromising joint integrity, allowing for the use of unmodified commercial off-the-shelf fasteners.
Implementation Method 1
a spring configured to be associated with the first and second sleeves and operable to form at least a portion of a second load path parallel to the first load path between the fastener and the component to facilitate biasing the fastener away from the component
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3~6
AI summary
A biasing system (101) for use with a fastener (120) is disclosed. The biasing system (101) can include a sleeve (130, 130b) configured to be disposed about a shank (122) of a fastener (120) and operable to form at least a portion of a first load path between the fastener (120) and a component (110) coupled to the fastener (120) to preload the fastener (120) through the sleeve (130a, 130b). The biasing system (101) can also include a spring (140) configured to be associated with the sleeve (130a, 130b) and operable to form at least a portion of a second load path parallel to the first load path between the fastener (120) and the component (110) to facilitate biasing the fastener (120) away from the component (110).