Lever-Operated Cutter for Separating Anchor Heads from Shafts

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Solution Overview

Problem

Existing tools are ineffective in easily separating heads from anchored shanks, particularly when the shank is inaccessible due to the head resting on a surface, especially in high-strength and tough steel materials used in tunnel construction.

Innovation Solution

A tool with movable jaws featuring projecting and recessed cutting edges that allow the shank to be pulled out from its anchored position by the recessed edges and then severed by the projecting edges, designed to handle high-strength and tough steel materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional cutting tool is used to separate the head from the shank, then the cutting edge must access the shank directly, but the head resting on the surface blocks access to the shank

Engineering Contradiction:
Improveaccessibility of shank to cutting toolVSAvoidtool design complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The cutting tool is segmented into two distinct jaw types: upper jaws with recessed cutting edges for penetrating between the head and surface, and lower jaws with projecting cutting edges for severing the shank. This segmentation allows each jaw type to perform its specific function without interference from the head-surface contact

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The upper jaws with recessed cutting edges perform a preliminary action by penetrating between the head and the surface to lift the head slightly, thereby creating access to the shank before the lower jaws can sever it. This preliminary lifting action resolves the accessibility problem without requiring complex positioning mechanisms

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If sharp cutting edges are used to penetrate between the head and surface, then penetration is facilitated, but the cutting edges are subjected to high stress and may break or chip

Engineering Contradiction:
Improvepenetration capabilityVSAvoidcutting edge durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Different parts of the tool have different cutting edge qualities tailored to their specific functions: the upper jaws have sharp recessed cutting edges optimized for penetration with minimal stress, while the lower jaws have robust projecting cutting edges optimized for cutting. This local differentiation of quality allows each part to excel at its specific task without compromising overall reliability

Inventive Principle:
Principle #3Local quality

3Strength

If the tool applies sufficient force to cut through high-strength steel shanks, then the shank is severed, but the tool structure may be damaged or the cutting edges may break

Engineering Contradiction:
Improvecutting capability through high-strength steelVSAvoidtool damage risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The cutting force application is segmented into two stages: first, the upper jaws apply localized force to lift the head with minimal stress on cutting edges; second, the lower jaws apply the full cutting force to sever the shank. This segmentation distributes the harmful forces differently across the tool structure and cutting edges, reducing the risk of tool damage while maintaining high-strength cutting capability

Inventive Principle:
Principle #1Segmentation

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

Enables quick and efficient separation of heads from shanks, even in high-strength steel, without damaging the tool, by using sharp recessed edges for penetration and blunt projecting edges for cutting, thus facilitating the removal of fire protection panels in tunnel construction.

Implementation Method 1

the recessed cutting edges are not used for cutting, but penetrating between the head and the surface like wedges

Methodology Applied
Scientific EffectWedge: Wedge

Implementation Method 2

the projecting cutting edges come so close together that they sever a shank located between them

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2875888B1Tool, system and method for separating a head from a shaft
Publication Date: 2016.11.02 FISCHERWERKE ARTUR FISCHER GMBH & CO KG
  • EP2875888B1 patent drawingFigure 1
  • EP2875888B1 patent drawingFigure 2
  • EP2875888B1 patent drawingFigure 3~4

AI summary

The invention relates to a tool (1) for separating the head from the shaft of a self-expanding expansion anchor made of high-strength steel. The invention proposes a lever-operated front cutter (2) with a recessed, sharp-edged cutting edge (4) and a projecting, rounded cutting edge (5) on each jaw (6). By closing the jaws (6), the sharp-edged, recessed cutting edges (4) are forced under the head of the expansion anchor and lift it slightly from the anchor base, so that the shaft can then be cut through with the projecting, rounded cutting edges (5). A stop (11) located to the side of the projecting cutting edges (5) serves for lateral positioning.