Insert Nut Groove Structure for Tool-Free, Low-Stress Assembly
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Solution Overview
Problem
The press fitting of insert nuts into injection molded structures often results in deformation or damage due to applied stress, making it difficult to assemble products without tools and identifying durability issues.
Innovation Solution
An insert nut insertion structure featuring a bolt fastening portion with threads, a flange portion, and a nut fixing groove with cantilever fingers made of elastic material, allowing easy manual insertion and distributing fastening force away from the fingers to prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insert nut is press fitted into the injection molded structure using conventional methods (hammering), then the insert nut can be securely installed, but the injection molded structure is subjected to high stress causing deformation or damage
Solution Approach 1:
The patent applies preliminary action by pre-forming expansion holes in the injection molded structure before insert nut installation. These expansion holes are designed to gradually expand during the installation process, allowing the insert nut to be secured without subjecting the structure to sudden high stress from hammering. The gradual expansion prevents deformation and damage while ensuring reliable installation.
Solution Approach 2:
The patent implements beforehand cushioning by designing the expansion holes to progressively increase in diameter during installation. This gradual expansion acts as a cushioning mechanism that absorbs and distributes the installation stress over time and space, preventing concentrated stress that would cause deformation or damage to the injection molded structure while still achieving secure insert nut installation.
2Reliability
If conventional press fitting methods are used, then the insert nut can be installed, but tools such as hammers are required making assembly complex and difficult
Solution Approach 1:
The expansion holes are pre-formed in the injection molded structure during the molding process itself. This preliminary preparation eliminates the need for subsequent mechanical expansion operations requiring hammers or other tools. The pre-formed holes are designed to self-expand during insert nut installation, enabling tool-free assembly while maintaining reliable installation.
Solution Approach 2:
The injection molded structure with pre-formed expansion holes performs the expansion function itself during insert nut installation without requiring external tools. The structure's own geometry and material properties enable the gradual expansion process, making the system self-sufficient and eliminating dependency on external hammering tools for assembly.
3Reliability
If insert nuts are pre-installed by insert molding, then assembly performance and durability are improved, but manufacturing cost increases and not all products require this level of complexity
Solution Approach 1:
The expansion holes are pre-formed during the injection molding process itself, combining the benefits of insert molding (preparation during manufacturing) with the flexibility of post-molding assembly. This preliminary preparation of expansion holes achieves improved assembly performance and durability without requiring complete insert molding, thus controlling manufacturing costs for products that don't need full insert molding complexity.
Solution Approach 2:
The patent applies local quality by pre-forming expansion holes only at specific locations where insert nuts will be installed, rather than requiring complete insert molding of the entire structure. This localized preparation provides the durability benefits of insert molding only where needed, reducing overall manufacturing cost while maintaining assembly performance at critical joints.
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
Prevents deformation and damage of injection molded structures by minimizing stress during insert nut insertion and enabling tool-free assembly, enhancing product durability and assembly efficiency.
Implementation Method 1
a pair of fingers provided on the flange portion positioned in the flange receiving portion and formed in a cantilever shape
Data Source
AI summary
An insert nut insertion structure includes an insert nut having a bolt fastening portion having threads on an inner circumference into which a bolt is configured to be screwed, and a flange portion on an outer circumference of the bolt fastening portion and extended in a circumferential direction of the bolt fastening portion; and a nut fixing groove into which the insert nut is inserted in a direction perpendicular to a direction in which the bolt is screwed. The nut fixing groove includes a flange receiving portion having an internal space conforming to a shape of the flange portion with the flange portion disposed in the flange receiving portion; and a pair of fingers having a cantilever shape that surrounds, in part, a periphery of the bolt fastening portion.