Expandable Threaded Fastener for Non-Rotational Thread Engagement
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Solution Overview
Problem
Conventional fasteners that engage threaded openings often degrade the threads due to repeated rotation, causing material fatigue and ergonomic issues, and may not be compatible with various opening types.
Innovation Solution
A fastener design featuring two threaded shaft elements with a releasable constriction and expansion mechanism, guided by an internal alignment shaft with tapered sections, allowing insertion without rotation, which prevents thread wear and adapts to different opening sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional threaded fasteners are repeatedly inserted and removed by rotation, then the fastening function is achieved, but the threads on the fastener and within the opening are degraded
Solution Approach 1:
Instead of rotating the fastener to insert it (conventional method), this invention inverts the approach by having the fastener insert axially without rotation. The threaded shaft elements are constrained in a constricted state during insertion, then expanded after insertion to engage the threads, eliminating rotational wear on both the fastener and opening threads.
Solution Approach 2:
The fastener employs dynamic transformation of the threaded shaft elements from a constricted state (during insertion) to an expanded state (after insertion). This dynamic state change allows the fastener to adapt its diameter, enabling non-rotational insertion while maintaining thread engagement capability, thus preserving thread durability.
2Reliability
If conventional non-rotational fasteners are used to avoid rotation, then thread degradation is reduced, but the openings must be sized to the fastener and compatibility with all opening types is limited
Solution Approach 1:
The threaded shaft elements dynamically change diameter between constricted and expanded states. During insertion, they are constricted to fit through various opening sizes without rotation. After insertion, they expand to engage threads in the opening, providing adaptability across different opening types while preserving threads.
Solution Approach 2:
The invention changes the physical parameter of the shaft elements' diameter through the constriction/expansion mechanism. This parameter change enables the same fastener to accommodate different opening sizes and types while maintaining thread engagement capability, significantly improving opening compatibility.
3Productivity
If repeated rotation of fasteners is performed, then fastening and unfastening operations are completed, but material fatigue occurs in the workpieces and ergonomic injuries may result
Solution Approach 1:
The invention inverts the conventional rotational insertion method by using axial insertion without rotation. The cap is depressed axially to drive the constricted shaft elements through the openings, eliminating repetitive rotational motions that cause material fatigue and ergonomic injuries while maintaining fastening productivity.
Solution Approach 2:
The invention replaces the rotational mechanical system with an axial compression system. Instead of rotating the fastener to insert it, the cap is axially depressed to push the constricted shaft elements through the openings. This substitution eliminates harmful repetitive rotation while achieving the same fastening result efficiently.
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 without degrading threads, maintaining compatibility with various openings and reducing ergonomic strain by eliminating the need for rotational insertion.
Implementation Method 1
The at least one radial spring is configured to constrict about the first shaft element and the second shaft element such that the first shaft element and the second shaft element move laterally inward toward the internal alignment shaft
Implementation Method 2
The at least one compression spring is configured to allow the first shaft element and the second shaft element to move laterally outward away from the internal alignment shaft
Implementation Method 3
The first shaft element and the second shaft element move along tapered sections of an internal alignment shaft of the fastener. The tapered sections guide the movement of the first shaft element and the second shaft element both laterally and axially relative to the internal alignment shaft
Data Source
AI summary
A fastener for engaging a threaded opening includes two shaft elements extending from a cap end to a shaft end and having a partially cylindrical shape, an internal alignment shaft surrounded by a central cavity, a releasable constriction mechanism, a releasable expansion mechanism, and a cap which can engage the cap ends of the shaft elements such that the shaft elements move relative to the internal alignment shaft. At least a portion of at least one shaft end includes external threads. The shaft elements are oriented about the central cavity and the central cavity is defined by internal surfaces of the shaft elements. The releasable constriction mechanism can constrict about the shaft elements such that the shaft elements move inward toward the internal alignment shaft. The releasable expansion mechanism can allow the shaft elements to move away from the internal alignment shaft.