Portable Rescue Cutter Torque Control From Cutting Plane Deviation

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Solution Overview

Problem

Portable motor-driven rescue devices face operational reliability issues when cutting hard materials, as the force buildup can cause cutting blades to rotate and spread, leading to potential damage and injury due to increased tension on components.

Innovation Solution

The method involves setting the angular position of the cutting plane in relation to the force applied, using motor current as a parameter to control the device, and triggering an operational event such as a warning or overload limitation when critical angular deviations are reached, ensuring real-time control and prevention of damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the cutting tool applies increasing force to penetrate hard materials, then the cutting ability is improved, but the cutting tool rotates towards the material causing component stress and potential breakage

Engineering Contradiction:
Improvecutting forceVSAvoiddevice reliability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The control unit continuously monitors the angular position of the cutting plane relative to the longitudinal axis and compares it against a predetermined maximum angular deviation. When the angular position exceeds this threshold, the control unit automatically reduces the drive torque of the electric motor, creating a feedback loop that prevents excessive rotation and component failure while allowing effective cutting within safe parameters.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the drive torque based on real-time angular position measurements. The electric motor's torque output is not fixed but varies continuously according to the cutting tool's angular deviation from the optimal cutting position, enabling the system to adapt force application to maintain both cutting effectiveness and operational safety.

Inventive Principle:
Principle #15Dynamics

2Strength

If the cutting blades are hardened to cut harder materials, then the cutting capability is improved, but the central bolt and components under the blades experience increasing stress

Engineering Contradiction:
Improveblade hardnessVSAvoidcomponent stress
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The system uses angular position sensors to provide continuous feedback on the cutting tool's orientation. When hard materials cause the cutting plane to rotate beyond the maximum angular deviation, the control unit reduces drive torque, thereby reducing the stress transmitted to the central bolt and underlying components, preventing breakage even when using hardened blades for cutting hard materials.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system proactively reduces drive torque before component failure can occur by monitoring angular position and comparing it against predetermined safety thresholds. This preliminary anti-action prevents the stress buildup that would lead to central bolt failure or component breakage during cutting operations on hard materials.

Inventive Principle:
Principle #9Preliminary anti-action

3Shape

If the cutting tool rotates under load towards the material, then the blades spread further apart, but this places components under increasing stress leading to breakage

Engineering Contradiction:
Improveblade spacingVSAvoidcomponent strength
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The control unit continuously monitors the angular position of the cutting plane and automatically reduces drive torque when the maximum angular deviation is exceeded. This feedback mechanism prevents excessive blade spreading that would compromise component strength, maintaining both cutting effectiveness and structural integrity during operation on hard materials.

Inventive Principle:
Principle #23Feedback

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

This approach enhances operational safety by preventing damage to the device and reducing the risk of operator injury through controlled intervention during cutting operations, particularly when dealing with hard materials.

Implementation Method 1

a self-contained work or rescue device (1), in particular a portable cutting tool, with an electric motor (4)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a position sensor (15) for determining the angular position W of the cutting plane E1 of the work or rescue device (1) in space

Methodology Applied
Scientific EffectPosition sensing:

Implementation Method 3

The force applied to the workpiece, or the resulting pressure, is determined or derived by measuring the current P1 drawn by the electric motor

Methodology Applied
Scientific EffectElectrical resistance measurement: Electrical Resistance

Data Source

PatentEP3737474B1Method for operating a working device or rescue device, and working device or rescue device
Publication Date: 2022.03.23 LUKAS HYDRAULIK
  • EP3737474B1 patent drawingFigure 1~2
  • EP3737474B1 patent drawingFigure 3
  • EP3737474B1 patent drawingFigure 4a

AI summary

The present invention relates to a method for operating an electromechanical or electrohydraulic working device or rescue device (1), which can be carried by an operating person and can be used autonomously, said working device or rescue device comprising: - a cutting tool (2) having two cutting tool halves (2a, 2b), which can be moved toward and away from one another and define a virtual cutting plane E1 by their movement; - a housing (3); - an electric motor (4); - a pump (5) driven by the electric motor (4) or a mechanical transmission driven by the electric motor, in each case for actuating the tool insert; an exchangeable rechargeable electrical energy source (6), which is accommodated in or on the working device or rescue device on the device side and which has its own housing (6a), wherein: - during the operation of the working device or rescue device (1), the orientation of the working device or rescue device (1) is sensed; and - the relation between the angular position W of the cutting plane E1 of the working device or rescue device (1) in space and the force applied by the cutting tool (2) to the object to be cut (10) is established and the working device or rescue device (1) is controlled in dependence on said relation.