Chisel Protruding Structure for Differential Inductive Hardening
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Solution Overview
Problem
Demolition tools, such as chisels, face high demands for robustness and durability but struggle with conventional heat treatments that cannot effectively differentiate hardness profiles across different sections, leading to inadequate stress resistance and wear management.
Innovation Solution
A chisel design with a protruding structure featuring a finite gradient along its surface allows for differential hardening through inductive hardening, where the heating power and feed rate can be varied, enabling through-hardening for the working section and shell-hardening for the connection end, combined with a hexagonal cross-section and grooves for enhanced durability and mounting security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional heat treatments are used, then the tool can be hardened uniformly, but different sections cannot achieve different hardness profiles required for differential stress resistance
Solution Approach 1:
The protruding structure creates distinct zones (first half and second half) that can be treated differently during hardening. The first half can be through-hardened while the second half remains shell-hardened or differently hardened, allowing each section to have optimal hardness for its specific functional requirements.
Solution Approach 2:
The tool shaft is divided into two halves by the protruding structure, enabling independent heat treatment of each half. This segmentation allows the working section to be through-hardened for abrasion resistance while the connection end can be shell-hardened to maintain toughness.
2Strength
If the protruding structure has a perpendicular surface to the longitudinal axis, then manufacturing is simplified, but the structure shades itself during treatment preventing uniform hardening
Solution Approach 1:
The protruding structure is designed with a curved surface that has a finite gradient along the longitudinal axis, eliminating perpendicular surfaces. This curved geometry prevents self-shading during heat treatment, allowing the heating medium to access all surfaces uniformly and achieve consistent hardening throughout the structure.
3Reliability
If the tool is through-hardened throughout, then abrasion resistance is maximized, but toughness and resistance to external damage decrease
Solution Approach 1:
Different sections of the tool are given different hardness levels: the working section is through-hardened for maximum abrasion resistance, while the connection end is shell-hardened or differently hardened to maintain toughness and resistance to external damage. This local differentiation optimizes both wear resistance and structural integrity.
Solution Approach 2:
The heat treatment parameters (heating power, feed rate, temperature distribution) are varied along the length of the tool to achieve different microstructures in different sections. This allows optimization of hardness and toughness for each specific functional requirement of different tool sections.
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 solution provides a robust and durable tool with tailored microstructures for each section, effectively managing abrasive stress and external damage, while maintaining toughness and abrasion resistance, enabling efficient and controlled hardening processes.
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
The method may comprise a second step of cooling the tool by spraying a coolant along a direction along which the surface of the protruding structure of the tool does not even partly shade itself
Data Source
Figure 1~4
AI summary
The invention relates to a tool (10), in particular a chisel, for a power tool, the tool (10) having a longitudinal axis (L) and comprising a working section (12) and a shaft (14) with a connection end (16) for connecting the tool (10) to a tool holder of the power tool, wherein the shaft (14) comprises at least one protruding structure (18) protruding from the shaft (14). It is characterized in that at least within one of two halves (A, B) of the protruding structure (18), which are separated by a plane perpendicular to the longitudinal axis (L), the surface of the protruding structure (18) has a finite gradient along a direction parallel to the longitudinal axis (L).