Protruding Chisel Shaft Geometry for Differential Hardening
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Solution Overview
Problem
Existing tools, such as chisels, face challenges in achieving high robustness and durability during demolition works due to uneven stress distribution and conventional hardening methods that do not allow for differential treatment of sections.
Innovation Solution
A chisel design with a protruding structure having a finite gradient along the longitudinal axis, allowing for differential hardening through induction heating and controlled cooling, resulting in sections with varying microstructures for enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hardening methods are used, then the tool can be hardened uniformly, but differential treatment of sections is not possible, reducing durability
Solution Approach 1:
The tool shaft is segmented into multiple sections along its longitudinal axis, each capable of receiving different treatments. The protruding structure creates distinct zones that can be independently hardened or treated based on their specific functional requirements, allowing the working section to have different microstructural properties than the connection section.
Solution Approach 2:
Different sections of the tool shaft are given different local qualities through selective hardening treatments. The working section receives through-hardening for maximum durability, while other sections may receive shell-hardening or remain softer, optimizing the overall tool performance by matching material properties to functional demands.
2Shape
If the protruding structure has a perpendicular surface, then it projects maximally from the shaft, but the surface shades itself during treatment, preventing uniform hardening
Solution Approach 1:
The protruding structure incorporates curved or rounded surfaces instead of flat perpendicular faces. This curvature ensures that no portion of the surface is hidden from the hardening medium or heat source during treatment, allowing uniform and complete hardening of the entire protruding structure while maintaining its geometric integrity.
3Strength
If the tool is made uniformly hard, then it resists wear well, but it becomes brittle and less durable under uneven stress
Solution Approach 1:
The tool employs non-uniform microstructure distribution along its length. High-carbon martensitic structures providing wear resistance are concentrated in the working section, while lower-carbon or differently treated sections maintain toughness and ductility. This gradient in material properties optimizes both wear resistance and impact resistance.
Solution Approach 2:
The tool shaft effectively becomes a composite structure with different material zones along its length. Each zone has tailored microstructural characteristics (different hardness, carbon content, or phase composition) suited to its specific functional requirements, creating a multi-phase or multi-composition system that balances contradictory properties.
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 enables efficient hardening methods that enhance the chisel's durability and resistance to wear, ensuring robust performance during demanding tasks like demolition.
Implementation Method 1
the tool may be hardened by inductive hardening. By way of inductive hardening, an applied heating power and a feed rate of the tool may be changed along the entire length of the tool
Implementation Method 2
Each of the sections may be adapted to the specific demands it is to face... the tool may contain at least two sections of different microstructure
Data Source
AI summary
The invention relates to a tool for a power tool, the tool having a longitudinal axis (L) and comprising a working section and a shaft with a connection end for connecting the tool to a tool holder of the power tool, wherein the shaft comprises at least one protruding structure protruding from the shaft. It is characterized in that at least within one of two halves (A, B) of the protruding structure, which are separated by a plane perpendicular to the longitudinal axis (L), the surface of the protruding structure has a finite gradient along a direction parallel to the longitudinal axis (L).