Magnetic Tool Retraction for Safer Machine Tool Operation

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Solution Overview

Problem

Machine tools, such as circular saws, pose a risk of injury due to their rotating components, and existing safety systems are inadequate in completely isolating the tool from the user, often failing due to carelessness or incorrect use of protective devices.

Innovation Solution

A safety system for machine tools that utilizes at least two magnetically opposed or magnetizable magnetic means to move the tool from a working position to a safety position using magnetic force, allowing for rapid and safe retraction of the tool from potential harm, with the option of additional forces like gravity or spring mechanisms to support the movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical safety devices are used to isolate the tool from the user, then physical protection is provided, but the devices can be bypassed through carelessness, disassembly, or incorrect use

Engineering Contradiction:
Improvesafety reliabilityVSAvoiduser compliance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces mechanical safety devices with a magnetic field-based safety system. The magnetic holding force keeps the tool in the working position, and when a hazardous situation is detected, the magnetic force is deactivated causing the tool to be automatically retracted by spring force. This eliminates mechanical safety guards that users can bypass, as the magnetic system provides inherent safety through field-based control rather than physical barriers.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Speed

If traditional electromagnetic actuators are used to move the tool, then positioning is achieved, but wear and tear occurs and triggering times are delayed

Engineering Contradiction:
Improvetriggering speedVSAvoidcomponent durability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent substitutes traditional electromagnetic actuators with a magnetic field holding system combined with spring force for tool retraction. The magnetic means (electromagnets or permanent magnets) hold the tool in position without continuous mechanical contact, and when deactivated, the spring automatically retractsthe tool without mechanical wear. This eliminates the wear and tear associated with traditional actuators while achieving faster triggering times.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic holding force is activated only when needed to maintain the tool in the working position, and deactivated immediately when a hazardous situation is detected. This periodic activation rather than continuous operation reduces energy consumption and allows for faster response times when safety intervention is required.

Inventive Principle:
Principle #19Periodic action

3Reliability

If magnetic force is used to move the tool, then wear is minimized and triggering is faster, but additional forces are needed to support the movement

Engineering Contradiction:
Improvesystem durabilityVSAvoidforce system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a spring force mechanism to counterbalance the tool's weight and assist in its retraction. The spring is pre-loaded to provide the necessary force to move the tool from the working position to the retracted position when the magnetic holding force is deactivated. This counterbalancing approach eliminates the need for complex active drive systems while ensuring reliable tool retraction.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 system effectively reduces the risk of injury by quickly and reliably moving the tool to a safe position, minimizing latency and wear, and allowing for fast triggering times without destructive forces, thus enhancing user safety during operation.

Implementation Method 1

the movement of the tool from the working position to the safety position by the movement device can be triggered and/or at least partially carried out by means of magnetic force

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP3403762B1Machine tool with safety system
Publication Date: 2023.09.13 FELDER KG
  • EP3403762B1 patent drawingFigure 1a
  • EP3403762B1 patent drawingFigure 1b
  • EP3403762B1 patent drawingFigure 2a

AI summary

Safety system (1) for a machine tool (2) with a tool (3), a clamping device (5) for the tool (3) movably arranged on a frame (4) of the machine tool (2), wherein the clamping device (5) can be moved by a movement device (6) from a working position in which the tool (3) can be used for work and there is a risk of injury to a user from the tool (3) to a safety position in which there is essentially no risk of injury to the user from the tool (3), wherein the movement device (6) has at least two magnetic means (7, 8) that are magnetized in the same or opposite directions and/or magnetizable, of which at least a first magnetic means (7) is connected to or arranged on the tool (3) and at least a second magnetic means (8) is connected to or arranged on the frame (4),so that the movement of the tool (3) by the movement device (6) from the working position to the safety position can be triggered and/or at least partially carried out by means of magnetic force.