Twisted Chisel Section Prevents Jamming

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Solution Overview

Problem

Conventional chisels tend to get stuck or jam in materials during deep penetration and pose a risk to users from flying rock fragments.

Innovation Solution

A chisel design featuring a twisted second working section with successive cross-sectional areas rotated about the longitudinal axis, which applies rotational forces to prevent jamming and deflects rock fragments, combined with a pyramid-shaped or conical tip for deep penetration and a cylindrical design for reduced resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a pointed chisel with a polygonal cross-section is used for deep penetration, then penetration depth is improved, but the chisel tends to get stuck or jammed in the material

Engineering Contradiction:
Improvepenetration depthVSAvoidjamming resistance
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The chisel implements a twisted second working section with successive cross-sectional surfaces rotated relative to each other about the longitudinal axis, creating a helical or spiral geometry. This curved/twisted design prevents the chisel from getting stuck or jammed in the material during deep penetration, while maintaining the pointed tip for effective entry.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Device complexity

If a conventional chisel profile is used, then structural simplicity is maintained, but rock fragments are directed towards the person handling the chisel

Engineering Contradiction:
Improvechisel profile simplicityVSAvoidrock fragment direction
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The twisted second working section with rotated cross-sectional surfaces creates a spiral profile that naturally deflects rock fragments away from the operator. The helical geometry redirects the ejection path of broken material, solving the safety issue without requiring additional protective components.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Length of moving object

If a conically shaped second working section is used, then penetration capability is improved, but additional resistance from the material must be overcome

Engineering Contradiction:
Improvepenetration capabilityVSAvoidresistance force
Core Design Contradiction:
Length of moving objectVSForce

Solution Approach 1:

The twisted second working section with rotated cross-sections creates a spiral geometry that reduces material resistance during penetration. The helical shape allows the chisel to rotate and wear away side walls of the channel being created, reducing friction and clamping forces compared to a conventional conical shape.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 prevents jamming and safely directs rock fragments away from the user, enabling deeper penetration and faster work progress while maintaining structural stability.

Implementation Method 1

the chisel also exerts rotational forces on the material to be worked when the second working section penetrates the material. These rotational forces wear away or damage the side walls of the channel that the chisel creates when penetrating the material

Methodology Applied
Scientific EffectRotational forces:

Implementation Method 2

the twisted design of the second working section causes rock fragments to be deflected

Methodology Applied
Scientific EffectDeflection:

Data Source

PatentEP2205403B1Chisel, particularly for motor-driven machines
Publication Date: 2018.11.21 ROBERT BOSCH GMBH
  • EP2205403B1 patent drawingFigure 1a~1c
  • EP2205403B1 patent drawingFigure 2a~2c
  • EP2205403B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a chisel (1), particularly for motor-driven machines (2), comprising a plug-in end (3) on the machine side for receiving the chisel (1) in the machine (2), a working end (5) located opposite the plug-in end (3), and a connecting section (4) between the plug-in end (3) and the working end (5), wherein the working end (5) comprises a first working section (6) and a second working section (7), wherein the first working section (6) is tapered to a cutting tip (9) or a cutting edge, wherein the second working section (7) is profiled between the first working section (6) and the connecting section (4) of the chisel (1), and wherein all cross-sectional surfaces of the second working section (7) that are oriented perpendicular to a longitudinal axis (11) of the chisel (1) are congruent with each other. The cross- sectional surfaces of the second working section (7) following each other consecutively along the longitudinal axis (11) of the chisel (1) and disposed perpendicular to the longitudinal axis (11) are arranged rotated relative to each other about the longitudinal axis (11) of the chisel (1).