Machine Tool Switch Interlock Using Sequential Magnetic Actuation

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Solution Overview

Problem

Existing operating devices for machine tools, such as grinding devices, are complex and costly due to the need for complex coupling drives or link guides to ensure safety through dual independent operations, which can lead to accidental activation and increased risk during handling.

Innovation Solution

An operating device with a first and second switching element, where the second switching element can only be set to its second mode when the first switching element is set to its second mode, incorporating elastomer attachments and signaling means for enhanced safety and moisture resistance, and a membrane keyboard for simplified operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If combined mechanical switches with coupling drives or link guides are used to ensure dual independent operations, then safety against accidental activation is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical coupling drives and link guides with a magnetic field-based switching mechanism. The first and second switching elements are coupled through a magnetic field, allowing the second switching element to only be actuated when the first switching element is already in the on position. This eliminates the need for complex mechanical linkages while maintaining the safety function of requiring two independent operations to activate the machine tool.

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

2Reliability

If combined mechanical switches with coupling drives are used to ensure dual independent operations, then safety against accidental activation is improved, but manufacturing cost increases

Engineering Contradiction:
ImprovesafetyVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive mechanical coupling drives and link guides with a magnetic field-based switching mechanism. This substitution significantly reduces manufacturing costs while maintaining the safety function. The magnetic coupling mechanism is simpler to manufacture and assemble, eliminating the need for precision-machined mechanical linkages and reducing overall component costs.

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

3Reliability

If complex coupling drives or link guides are implemented in switches, then dual independent operations for safety are achieved, but the switching device becomes cost-intensive

Engineering Contradiction:
ImprovesafetyVSAvoidcost-intensive
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent eliminates complex mechanical coupling drives and link guides by implementing a magnetic field-based switching mechanism. This substitution dramatically reduces manufacturing costs while maintaining the safety function of requiring two independent operations. The magnetic coupling approach uses simpler, more cost-effective components that are easier to manufacture and assemble.

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

4Reliability

If the second switching element can only be set to second mode when the first switching element is in second mode, then accidental activation is prevented, but ease of operation may be reduced

Engineering Contradiction:
ImprovesafetyVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent uses a magnetic field-based coupling mechanism that automatically enables or disables the second switching element based on the state of the first switching element. When the first switching element is off, the magnetic field prevents the second switching element from being actuated. When the first switching element is on, the magnetic field enables the second switching element. This automatic magnetic coupling simplifies the user interface compared to complex mechanical interlocks, maintaining ease of operation while ensuring safety.

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

Data Source

PatentEP3533076B1Switch device for machine tool
Publication Date: 2023.11.29 HILTI AG
  • EP3533076B1 patent drawingFigure 1
  • EP3533076B1 patent drawingFigure 2
  • EP3533076B1 patent drawingFigure 3a

AI summary

The invention relates to an operating device (1) for a machine tool, containing at least a first and a second switching element (40, 50), wherein the first switching element (40) can be set to a first and a second mode and the second switching element (50) can be set to a first and a second mode, wherein the first switching element (40) contains at least one first signaling means (21) for signaling the first or second mode and the second switching element (50) contains at least one second signaling means (22) for signaling the first or second mode. The operating device is designed in such a way that the second switching element (50) cannot be set from the first mode to the second mode until the first switching element (40) has been set from the first mode to the second mode.