Hardness Tester Symmetrical Plate Spring Design
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Solution Overview
Problem
Conventional hardness testers face challenges in generating a large test force without damaging the cantilever plate spring and suffer from friction issues when using coil springs, limiting the dynamic range and accuracy of the test force.
Innovation Solution
A hardness tester design featuring a test force generating spring with left/right symmetrical through-holes and slits, allowing for linear motion and minimizing friction, which is interposed between the load applier and indenter column, enabling accurate and high-force indentation testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a cantilever plate spring is used to generate large test force, then the test force range is improved, but the plate spring may be damaged due to stress concentration
Solution Approach 1:
The plate spring is divided into multiple segments through through-holes, creating a segmented structure that distributes stress more evenly throughout the spring. This segmentation prevents stress concentration at any single location, allowing the spring to withstand larger test forces without damage while maintaining reliability.
2Force
If a cantilever plate spring is deformed to generate test force, then the test force is improved, but the free end position shifts requiring additional offset mechanisms
Solution Approach 1:
The plate spring features an asymmetric structure with through-holes positioned at specific locations that create a predetermined offset between the load applier and indenter column. This asymmetric design inherently compensates for the free end position shift during deformation, eliminating the need for additional offset mechanisms and reducing device complexity.
3Object-generated harmful factors
If a coil spring is used instead of plate spring, then friction is reduced, but expansion and compression friction still occurs requiring additional cancellation mechanisms
Solution Approach 1:
The invention extracts the problematic friction-generating coil spring structure and replaces it with a plate spring design where friction is inherently minimized. By taking out the coil spring's expanding and compressing mechanism and substituting it with a direct plate spring deformation system, the patent eliminates the need for friction cancellation mechanisms while maintaining low friction operation.
4Ease of operation
If the through-holes and slit are added to the test force generating spring, then the spring structure is improved for linear motion, but the manufacturing complexity increases
Solution Approach 1:
The through-holes and slit are combined into a single integrated feature set that can be manufactured together in one processing step. By merging these features into a unified design, the patent enables linear motion capability while minimizing the increase in manufacturing complexity, as the features are created simultaneously rather than requiring separate operations.
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
The design allows for a broad dynamic range of test forces with high accuracy, reducing the risk of spring damage and friction, thereby enhancing the performance of hardness testing.
Implementation Method 1
a test force generating spring that is interposed between the load applier and the indenter column... capable of generating a highly accurate test force through elastic deformation that is unlikely to produce friction and deformation of a spring by linear motion
Data Source
AI summary
A test force generating spring that is interposed between an indenter shaft provided with an indenter at a distal end and a press that linearly displaces the indenter shaft toward a sample stage so as to press the indenter into a surface of a sample is configured as an annular spring having left/right symmetry, the annular spring including a left/right pair of through-holes that are formed running from one side surface of a substantially rectangular metal block to another side surface on a rear side of the block and a slit that is formed so as to connect the pair of through-holes. With this configuration, a highly accurate test force can be generated and a hardness test can be favorably performed by a hardness tester.