Thin Flexure Joint With Segmented Recesses for Stress Distribution
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Solution Overview
Problem
Existing thin-point joints in monolithic link mechanisms, such as those used in weighing technology, face a trade-off between reducing flexural rigidity and maintaining strength under normal stresses, often resulting in reduced stability and material stress hotspots due to material removal techniques.
Innovation Solution
The design incorporates specially shaped recesses positioned and shaped to maintain strength properties constant along a selectable length from the thin point, with the thin point acting as a neutral zone of solid material, and recesses that increase material thickness beyond the thin point to distribute stress evenly, ensuring consistent strength and reduced flexural rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If material is removed from the thin section to reduce bending stiffness, then the joint becomes more flexible for pivoting movement, but the strength under normal stresses is reduced
Solution Approach 1:
The thin section is segmented into multiple regions: a thin-point region for flexibility and recess-free zones for strength. The recesses are strategically positioned to segment the material removal in a way that preserves structural integrity while achieving the desired flexibility.
Solution Approach 2:
Different regions of the thin section are given different qualities: the thin-point region has minimal material for flexibility, while recess-free zones maintain full material thickness for strength. This local differentiation allows simultaneous optimization of both flexibility and strength in different areas.
2Stability of the object's composition
If the cross-section of the thin section is reduced to minimize bending stiffness, then pivoting movement is facilitated, but the load-bearing capacity is reduced
Solution Approach 1:
The thin section exhibits local quality variations with the thin-point region providing low bending stiffness for pivoting, while recess-free zones provide high load-bearing capacity. This spatial differentiation resolves the contradiction between flexibility and force transmission.
Solution Approach 2:
The solution moves from uniform cross-sectional reduction to a three-dimensional configuration where the thin section varies in thickness along its length. The recess-free zones add material in specific regions to maintain load-bearing capacity without compromising the overall flexibility provided by the thin-point region.
3Stability of the object's composition
If recesses are introduced to reduce material and stiffness, then bending resistance is decreased, but stress hotspots are created in the remaining material
Solution Approach 1:
The thin section is designed with local quality variations where recess-free zones provide uniform stress distribution and high strength, while the thin-point region provides flexibility. This prevents stress hotspots by avoiding material discontinuities in critical load-bearing areas.
Solution Approach 2:
The potential harm of stress concentration from material removal is converted into benefit by strategically positioning recess-free zones where they prevent stress hotspots, while allowing controlled material removal in non-critical areas to achieve the desired flexibility.
Data Source
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AI summary
The invention relates to a thin-spot joint with two material sections connected to each other via a material constriction (thin spot), wherein the material sections are provided with recesses such that the strength existing in the thin spot with respect to normal stresses or bending stresses is kept largely constant within a predefinable distance to the thin spot.