Asymmetrical V-Shaped Chisel Wings for Jamming Reduction

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Solution Overview

Problem

Conventional chisels for excavating rock or mineral building materials often experience jamming issues due to their rotationally symmetrical design, which limits their effectiveness in generating non-radial forces necessary for efficient breaking and penetration.

Innovation Solution

A chisel with a non-rotationally symmetrical working section featuring two V-shaped wings that increase in dihedral angle from the shank to the tip, providing radial and non-radial forces, and an asymmetrical design that reduces jamming by offsetting the center of gravity and varying wing dimensions along the longitudinal axis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a rotationally symmetrical point chisel design is used, then the chisel structure is simple and easy to manufacture, but the chisel experiences jamming in the ground and cannot generate non-radial forces for efficient breaking

Engineering Contradiction:
Improvechisel structure simplicityVSAvoidjamming resistance
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent applies asymmetry by designing the working section with two wings arranged in a V-shape that are not rotationally symmetrical. The wings have different radial dimensions and are positioned at different angles, creating an asymmetrical configuration that prevents jamming and enables generation of non-radial forces during rock breaking operations

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If a rotationally symmetrical point chisel design is used, then the manufacturing process is straightforward, but the chisel cannot generate non-radial forces necessary for efficient rock breaking

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidrock breaking efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The asymmetrical V-shaped wing configuration enables the chisel to generate non-radial forces during penetration, improving rock breaking efficiency by creating more effective stress distribution and fracture patterns in the rock material

Inventive Principle:
Principle #4Asymmetry

3Force

If the wings are arranged with a small dihedral angle, then the chisel generates strong radial forces for blasting rock, but the chisel experiences increased jamming in the ground

Engineering Contradiction:
Improveradial blasting forceVSAvoidjamming resistance
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The asymmetrical V-shape with optimized dihedral angle balances radial force generation with jamming resistance. The specific angular configuration and unequal wing dimensions create a compromise that maintains effective rock blasting while reducing ground jamming compared to symmetrical designs

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces dimensional variation by arranging wings in a three-dimensional V-configuration with specific dihedral angles rather than in a single plane. This spatial arrangement allows the chisel to generate radial forces while the asymmetrical positioning reduces jamming through non-uniform contact with the ground

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Force

If the wings are made with large radial dimensions, then the chisel generates strong forces for breaking rock, but the chisel experiences increased jamming and reduced penetration capability

Engineering Contradiction:
Improverock breaking forceVSAvoidpenetration capability
Core Design Contradiction:
ForceVSProductivity

Solution Approach 1:

The patent applies local quality by varying the radial dimensions of the wings along the longitudinal axis. The wings have different radial extents at different locations, with the asymmetrical configuration providing optimized local contact characteristics that maintain breaking force while reducing overall jamming and improving penetration

Inventive Principle:
Principle #3Local quality

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 chisel effectively reduces jamming and enhances breaking efficiency by generating a net force offset from the longitudinal axis, allowing for better penetration and reduced risk of jamming in rock or mineral materials.

Implementation Method 1

the chisel generates not only radial forces for blasting the rock but also non-radial forces acting along a vertical axis through the wings

Methodology Applied
Scientific EffectRadial forces: Mechanical Force

Implementation Method 2

the chisel generates not only radial forces for blasting the rock but also non-radial forces acting along a vertical axis through the wings

Methodology Applied
Scientific EffectNon-radial forces: Mechanical Force

Data Source

PatentEP3496902B1Chisel
Publication Date: 2020.04.01 HILTI AG
  • EP3496902B1 patent drawingFigure 1~2
  • EP3496902B1 patent drawingFigure 3~11

AI summary

The invention relates to a tool bit (1) has a shaft (2), an impact surface (5), a tip (3), a longitudinal axis (7), which extends through the impact surface (5) and the tip (3), and a working section (6). The working section (6) has a trunk (11), which is arranged on the longitudinal axis, and two wings (12), which extend along the trunk (11) and protrude radially from the trunk (11). The two wings (12) are arranged in a V shape.