Captive Fastener Assembly With Dual Float for Tolerance Alignment
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Solution Overview
Problem
Captive fastener systems face challenges in accommodating increased tolerances between structures while maintaining secure joining, as existing systems require precise manufacturing tolerances to align and attach structures effectively, limiting flexibility and adaptability.
Innovation Solution
The proposed captive fastener system includes a sleeve with internal threads to secure the fastener, a biasing element for additional stability, and a mounting assembly providing a first degree of movement, along with a captive fastener assembly offering a second degree of movement, allowing for increased tolerances and flexibility in alignment and attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional captive fastener systems are used, then secure joining is achieved, but manufacturing precision requirements are excessive and tolerances cannot be accommodated
Solution Approach 1:
The patent changes the geometric parameters of the fastener system by introducing a conical section with specific angle ranges (5-15 degrees) and dimensional relationships (L1: L2 ratios between 0.5-2.0). These parameter modifications enable the fastener to accommodate tolerance variations while maintaining secure joining through the conical locking mechanism.
Solution Approach 2:
The patent introduces dynamic elements including a spring component that provides elastic deformation capability and a conical section that allows rotational movement. These dynamic features enable the fastener to adapt to misalignment and tolerance variations during installation and operation, resolving the contradiction between secure joining and manufacturing precision requirements.
2Adaptability or versatility
If increased tolerances are accommodated, then flexibility and adaptability improve, but secure joining capability deteriorates
Solution Approach 1:
The patent modifies geometric parameters including the conical section angle (5-15 degrees), length ratios (L1: L2 between 0.5-2.0), and radial clearance specifications (0.05-0.5mm). These parameter changes enable the fastener to accommodate increased tolerances while maintaining secure joining through the conical locking mechanism that converts radial play into axial securing force.
Solution Approach 2:
The patent introduces a conical section as an intermediary element between the fastener shank and the hole wall. This conical mediator converts radial clearance and tolerance variations into axial securing force, enabling the system to accommodate increased tolerances while maintaining reliable joining through the intermediate conical locking mechanism.
3Measurement precision
If float capability is increased, then alignment precision improves, but device complexity increases
Solution Approach 1:
The patent optimizes geometric parameters including the conical section angle (5-15 degrees), length ratios (L1: L2 between 0.5-2.0), and radial clearance specifications (0.05-0.5mm). These parameter optimizations provide sufficient float capability for alignment precision while controlling device complexity through efficient geometric design rather than additional components.
Solution Approach 2:
The patent segments the fastener into distinct functional sections: a cylindrical section for initial insertion, a conical section for alignment and locking, and a threaded section for securing. This segmentation allows each section to perform its specific function efficiently, providing alignment precision through the conical section while maintaining relatively simple overall structure.
Data Source
AI summary
Captive fastener systems and structural assemblies having captive fastener systems are described. The captive fastener systems include a captive fastener assembly having a sleeve and a captive fastener arranged within the sleeve, a mounting assembly having a bushing and a mounting fastener arranged to pass through the bushing, and a joining body having a mounting aperture, wherein the sleeve is attached to the joining body and the bushing and the mounting fastener are configured to pass through the mounting aperture. The mounting assembly is configured to provide a first degree of movement of the captive fastener system and the captive fastener assembly is configured to provide a second degree of movement of the captive fastener system.