Swing-Arm Cutting Tool Pressure Mechanism for Clean Edge Exit

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Solution Overview

Problem

Conventional cutting devices experience unclean cuts due to tearing at the cutting edge exit, leading to depressions and chips remaining on the workpiece surface, despite efforts to use pressure media and rollers to prevent tear-out.

Innovation Solution

A cutting device with a rocker parallelogram mechanism that kinematically connects the protective hood to the saw unit, ensuring a rigid and aligned pressure medium, such as rollers, to maintain compressive stress at the cutting edge exit, preventing tear-out by aligning joint axes parallel to the saw blade's rotation axis and distributing pressure to match or exceed cutting pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If rollers are used as pressure medium to prevent tear-out at cutting edge exit, then cutting cleanliness is improved, but the roller suspension becomes too elastic causing sideways deflection and wear

Engineering Contradiction:
Improvecutting cleanlinessVSAvoidroller suspension stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The rocker arm is divided into multiple segments (first rocker arm segment, second rocker arm segment) connected by a joint. This segmentation allows the suspension to accommodate workpiece thickness variations through controlled relative movement between segments, reducing elastic deflection and sideways movement of the rollers while maintaining cutting pressure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rocker arm acts as an intermediary mechanism between the stationary housing and the rollers. It transmits the pressing force to the rollers while accommodating workpiece thickness variations through its articulated structure, preventing direct transmission of elastic deflection to the rollers and maintaining stable roller position.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the rocker arm is made more rigid to prevent roller deflection, then roller stability is improved, but the ability to adapt to different workpiece thicknesses is reduced

Engineering Contradiction:
Improveroller position stabilityVSAvoidworkpiece thickness adaptation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The rocker arm suspension is designed with articulated joints that allow dynamic adjustment of the roller position. The joint between rocker arm segments enables the suspension to adapt its configuration based on workpiece thickness, maintaining roller stability while providing adaptability through controlled movement rather than rigid fixation.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If the gap between roller and sawblade is reduced to prevent tear-out, then cutting cleanliness is improved, but the risk of roller wear and damage increases

Engineering Contradiction:
Improvecutting edge cleanlinessVSAvoidroller wear and damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The rocker arm suspension is designed to maintain proper roller positioning and prevent excessive sideways deflection before wear can occur. By providing stable support and controlled movement capability, the system prevents the roller from deflecting into the sawblade path, thereby preventing wear and damage before they can happen.

Inventive Principle:
Principle #9Preliminary anti-action

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

Ensures a clean cutting pattern by preventing chips from tearing out, maintaining kinetic energy for efficient chip removal, and reducing energy consumption in the extraction system.

Implementation Method 1

a fan driven by the drive motor and a device for removing dust from the interior of the protective hood, which includes an inlet opening introduced into the protective hood and connected to the pressure side of the fan

Methodology Applied
Scientific EffectSuction: Suction

Implementation Method 2

The goal is to ensure that as many chips as possible reach the air jet and the outlet opening as a result of their tangential propulsion. The already high tangential speed of the cutting tool's cutting edge, due to the physics of cutting, is useful for this.

Methodology Applied
Scientific EffectTangential propulsion: Centrifugal Force

Implementation Method 3

it is known to provide pressure media in the form of rollers on the side of the cutting tool on the cutting edge exit side of the workpiece in the area of the cutting edge exit, which generate a compressive stress in the area of the cutting edge exit

Methodology Applied
Scientific EffectCompressive stress: Compression

Implementation Method 4

compressive stress is applied via the rollers σ d in the form of Hertzian compression p H = σ d applied to the workpiece in the area of the cutting edge exit

Methodology Applied
Scientific EffectHertzian compression:

Data Source

PatentEP3849763B1Cutting device
Publication Date: 2025.10.22 FACHHOCHSCHULE KIEL
  • EP3849763B1 patent drawingFigure 1a~1b
  • EP3849763B1 patent drawingFigure 2~3
  • EP3849763B1 patent drawingFigure 4~5

AI summary

The invention relates to a cutting device having a housing (28). In this case, a driven disc-shaped cutting tool (10), mounted in the housing (28), for cutting a workpiece (12) is provided. Arranged on a circumferential side of the cutting tool (10) are cutting means (14) that each have an associated cutting edge (14a), said cutting means (14), during cutting, depending on an infeed rate of the cutting tool (10) relative to the workpiece (12), passing into the material to be cut of the workpiece (12) on a cutting-edge entry side of the workpiece (12), passing out on a cutting-edge exit side, remote therefrom, of the workpiece (12), and in the process cutting away material of the workpiece (12). In this case, at least one pressure means is provided, which exerts a pressure (pH) on the surface of the cutting-edge exit side, via a cutting-edge exit face, on the cutting-edge exit side to the side of the cutting tool (10) in the region (18) of the cutting edge (14a), and is mounted in a pivotable manner with respect to the housing (28). According to the invention, the pressure means (24) is mounted in and at one end of at least one swing arm (26). The swing arm (26) is connected to the housing (28) via a first joint (30), wherein the swing arm (26) is mounted so as to be pivotable about a first joint axis of the joint (30). The first joint axis is arranged parallel to the axis of rotation (32) of the cutting tool (10).