Captive Fastener Cam and Hold-Out Clip for Subpanel Access
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Solution Overview
Problem
Captive screws face challenges in securing panels from the opposite side and accessing subpanels due to their design limitations, particularly in applications where access is restricted.
Innovation Solution
A captive fastener with a spring-actuated cam member and a cantilevered hold-out clip, featuring an elongate slot and cavity, allows the fastener to pass through panels while being secured by a counterbore and subpanel, and prevents counter-rotation with a traverse force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional captive screw is used, then the fastener remains in the panel when loosened, but it cannot be secured from the opposite side or access subpanels
Solution Approach 1:
The fastener is divided into multiple functional components: a cam member for engagement with the counterbore, a hold-out clip for securing in the subpanel, and a threaded shank. These segmented components work together to enable operation from both sides of the panel while maintaining the captive function.
Solution Approach 2:
The hold-out clip is nested within the cavity of the fastener body, and the cam member is positioned within the structured engagement surface. This nesting allows multiple functions to be integrated into a compact fastener assembly that can operate in restricted spaces.
2Adaptability or versatility
If the fastener is designed to secure panels, then it provides broad fastening surface, but it cannot easily enter subpanels due to design limitations
Solution Approach 1:
The cam member is designed to rotate and engage dynamically with the counterbore, allowing the fastener to adapt its configuration as it passes through the panel and secures in the subpanel. This dynamic engagement enables versatility in panel fastening while facilitating easy subpanel access.
Solution Approach 2:
The fastener assembly performs multiple functions: it fastens the primary panel through the cam member engagement with the counterbore, and simultaneously secures the subpanel through the hold-out clip. This multi-functionality allows a single fastener to address both panel securing and subpanel access requirements.
3Reliability
If the fastener uses a retainer to prevent falling out, then it provides security, but it complicates the assembly and limits access
Solution Approach 1:
The hold-out clip is designed to automatically engage with the subpanel structure as the fastener is installed, providing self-retention without requiring additional retainers or complex assembly steps. The cam member similarly self-engages with the counterbore through rotational movement, maintaining reliability while simplifying the overall assembly.
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
Enables secure fastening from the opposite side of a panel and easy access to subpanels, maintaining the fastener's position without falling out, while allowing for easy disengagement with a lock nut.
Implementation Method 1
The cam member is spring actuated to extend out of the shank and can be retracted into the cavity against the bias of the spring
Implementation Method 2
The cam member is shaped to counter-rotate in the presence of a traverse force, such as the panel bearing against it
Data Source
AI summary
A captive fastener is disclosed having a longitudinal slot along the shank for receiving a hold-out clip, and a chamber that houses a retractable cam member. The cam member is spring actuated to extend out of the shank and can be retracted into the cavity against the bias of the spring to pass through a primary panel and subpanel. The cam member is shaped to counter-rotate in the presence of a traverse force, such as the panel bearing against it.