Offset Prong Speed Nut for Easy Disassembly
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Solution Overview
Problem
The existing speed nut designs, such as those described in U.S. Pat. No. 5,707,192, require a large pull-off force to disassemble components during product service due to rigid gripping of studs, making the disassembly operation difficult and costly.
Innovation Solution
A J-clip nut design featuring a fastener plate with offset root and terminal portions of prongs that deform plastically to enlarge the single-threaded hole, allowing easy disengagement from studs without excessive force, utilizing a fastener plate, clip plate, and side plate configuration to secure components without human assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the prongs are designed to grip the stud rigidly, then the fastening reliability is improved, but the disassembly difficulty increases due to large pull-off force required
Solution Approach 1:
The prong configuration is designed to be dynamic rather than static. The offset arrangement of root and terminal portions allows the prongs to deform plastically during installation to grip the stud securely, then deform elastically during disassembly to release the grip. This dynamic behavior enables the same structure to provide both strong fastening and easy removal.
Solution Approach 2:
The patent changes the physical state parameters of the prongs by creating an offset between the root portion and terminal portion. This geometric parameter change allows the prongs to transition between different deformation states - plastic deformation for secure gripping during fastening, and elastic deformation for easy release during disassembly. The offset distance is specifically designed to control these parameter transitions.
2Force
If the fastening hole is made smaller than the stud diameter, then the gripping force is improved, but the insertion difficulty increases
Solution Approach 1:
The fastening hole design incorporates dynamic deformation capability through the offset prong structure. During insertion, the prongs deform plastically to enlarge the hole and accommodate the stud. During fastening, the same prongs deform elastically to grip the stud with offset root and terminal portions. This dynamic deformation behavior resolves the contradiction between initial insertion ease and subsequent gripping force.
3Ease of manufacture
If the prongs are positioned symmetrically, then the manufacturing simplicity is improved, but the disassembly ease worsens due to rigid gripping
Solution Approach 1:
The patent intentionally introduces asymmetry in the form of an offset between the root portion and terminal portion of each prong. This asymmetric configuration is relatively simple to manufacture using standard stamping processes, yet it creates the necessary plastic and elastic deformation characteristics. The offset breaks the symmetry that would cause rigid gripping, enabling easy disassembly while maintaining manufacturing simplicity.
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 and easy disassembly of components by reducing the required pull-off force, preventing damage and simplifying product service operations.
Implementation Method 1
the flexible prongs are plastically deformed so that the fastening hole is enlarged according to the diameter of the stud
Implementation Method 2
The terminal portions of the flexible prongs ratchet over threads of the stud and apply a force to the stud to lock the speed nut
Data Source
AI summary
A speed nut for fastening a work piece to a stud includes a fastener plate defining an opening on a surface. The speed nut further includes a prong extending inwardly from an edge of the opening, the prong includes a root portion connecting with the fastener plate and a terminal end defining a single-threaded hole within the opening and configured to ratchet over threads of the stud. The root portion and the terminal portion are arranged offset from each other such that the prong plastically deforms in response to the work piece being removed from the stud.