Temporary Fastener With Opposite Hand Threads For Automated Installation
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Solution Overview
Problem
Existing temporary fasteners in the aeronautical industry are too large in diameter and height, preventing automatic installation tools from accessing holes between already-installed fasteners, leading to malfunctions and requiring manual intervention.
Innovation Solution
A temporary fastener design with a small diameter and height, featuring a body with a bearing surface, elastic half-clips, a threaded rod mechanism, and a control nut with opposite hand threads, allowing for compact assembly and automatic installation, and incorporating spring washers for secure retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fastener diameter and height are reduced to enable automatic installation tool access, then the ease of operation and extent of automation are improved, but the structural complexity increases due to the compact opposite hand thread mechanism
Solution Approach 1:
The patent combines the nut stopping function with the body tapping by using opposite hand threads, merging two separate functions (threaded connection and stopping mechanism) into a single integrated system. This eliminates the need for separate stopping elements and reduces overall fastener dimensions while maintaining functionality.
Solution Approach 2:
The control nut with opposite hand threads serves multiple functions simultaneously: it provides the threaded connection to the rod, acts as a stopping element against the body tapping, and enables compact dimensional design. This multi-functionality reduces the number of separate components needed.
2Productivity
If the fastener dimensions are reduced for automated installation, then the productivity and extent of automation are improved, but the reliability may worsen due to tighter tolerances in compact design
Solution Approach 1:
The patent changes the thread hand configuration to opposite hand threads, which fundamentally alters the mechanical interaction between the control nut and body. This parameter change enables the nut to be stopped by the tapping during removal without requiring additional clearance or tolerance adjustments, maintaining reliability in the compact design.
3Device complexity
If the control nut is stopped by the body tapping during removal, then the device complexity is reduced by eliminating separate stopping elements, but the manufacturing precision requirements increase
Solution Approach 1:
The body tapping is designed to serve dual purposes: providing the threaded connection point and acting as the stopping element for the control nut during removal. This merging of functions eliminates separate stopping elements but requires precise alignment and engagement between the nut thread and body tapping.
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 automated installation of metal sheets with reduced fastener diameter, facilitating the use of automatic tools and allowing for compact, efficient assembly and disassembly without the need for manual intervention.
Implementation Method 1
two elastic half-clips designed to pass through the holes, each clip having a hooking spur that can be applied to a rear surface of the structures to be assembled
Implementation Method 2
a mechanism that can be moved relative to the body, said mechanism comprising a threaded rod placed coaxially to the body, with one end of the rod connected to the half-clips, said mechanism also comprising a control nut mounted on said rod
Data Source
AI summary
The invention relates to a fastener (10) for the temporary assembly of at least two pre-drilled structures of the type comprising:a body (11) able to come into contact with a face of the structures to be assembled;a spacer (17), secured to said body;two elastic half-clips (15), each clip having a hooking spur (16);a mechanism that can be moved relative to the body, comprising a threaded rod (18) connected to the half-clips, and a control nut (20) mounted on said rod, the control nut comprising:an internal tapping (19) cooperating with the thread (25) of the rod;an external thread (26) cooperating with an internal tapping (28) of the body;the body thread and the control nut thread being opposite handed.