Expandable Collet Anchor with Captive Stud for Blind Fastening
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing anchor systems face challenges in securely fastening and easily removing components without deformation, particularly in applications requiring frequent assembly and disassembly, such as in the aerospace industry, where blind side fastening is necessary and non-permanent fastening is desired.
Innovation Solution
An expandable collet anchor system comprising a collet body with radially extending protrusions and a captive stud, where the stud's radially extending protrusion prevents dislocation by expanding the collet body's fingers radially outward, and a reduced diameter portion allows for free rotation and easy removal, along with enhanced friction means and axial biasing elements for secure engagement and disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If existing anchor systems use blind side fastening with non-permanent fastening, then ease of removal is improved, but secure fastening reliability deteriorates
Solution Approach 1:
The collet body transitions from a static component to a dynamic one that can expand and contract. When the stud is inserted, the collet body expands radially outward to grip the stud securely. When the stud is removed, the collet body contracts back to its original shape, enabling easy removal while maintaining secure fastening during operation
Solution Approach 2:
The system changes the dimensional parameter of the collet body by expanding it radially outward to engage with the stud. This parameter change allows the collet body to transition from a loose fit to a secure grip, resolving the contradiction between ease of removal and secure fastening
2Reliability
If existing anchor systems form threads in structures, then secure engagement is improved, but manufacturing complexity and time increase
Solution Approach 1:
The collet body is pre-formed with a specific geometry that allows it to expand and grip the stud without requiring thread formation in the stud or the structure. The expanding action creates the engagement mechanism in advance, eliminating the need for time-consuming thread formation operations
Solution Approach 2:
The invention extracts the thread formation requirement from the system. Instead of forming threads in the stud or structure, the collet body itself provides the engagement mechanism through radial expansion, eliminating the need for thread formation operations
3Reliability
If existing anchor systems use deformation-based fastening, then secure fastening is improved, but wear and fatigue increase
Solution Approach 1:
The system uses reversible parameter changes in the collet body's dimensions rather than permanent deformation. The collet body expands and contracts elastically, avoiding cumulative wear and fatigue that would result from deformation-based fastening methods
Solution Approach 2:
The dynamic expansion and contraction of the collet body provides secure fastening through controlled dimensional changes rather than permanent deformation. This dynamic approach reduces wear and extends component lifespan compared to static deformation-based systems
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 system provides secure, non-permanent fastening and easy removal of components without deformation, reducing wear and fatigue, and allows for frequent assembly and disassembly without requiring access to the underside of panels or forming threads in structures.
Implementation Method 1
an axial biasing element, such as a spring or resilient washer, disposed between the collet body and the stud and adapted to bias the collet body and the stud toward one another
Implementation Method 2
enhanced friction means and axial biasing elements for secure engagement and disengagement
Data Source
AI summary
A collet body and captive stud combination is disclosed wherein the collet body has a first end and adjacent first wall portion, and a protrusion extending from an exterior surface thereof. The first wall portion also defines at least two secondary slots to create at least two fingers. The collet body also has a second end including a collet head and an opening for receiving a stud. At least a portion of an interior surface of the collet body is threaded to rotationally receive a threaded stud. The stud includes a head, a body portion being at least partially threaded, a distal end and at least one radially extending protrusion at or proximate to the distal end. The protrusion may be circumferentially continuous or discontinuous. The stud body portion is sized to fit through the collet body second end, and to prevent dislocation of the stud from the collet body once inserted in a collet body, the maximum diameter of the stud at the radially extending protrusion is greater than the minimum diameter of any essentially non-elastic portion of the collet body.