Guard Access Safety Switch With Vibration-Resistant Locking

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Solution Overview

Problem

Existing safety switches for industrial machines and plants have limitations in providing immediate and unmistakable signal reading, are prone to accidental unlocking due to vibrations or impacts, and lack customization options for signal lights.

Innovation Solution

A safety switch with a locking mechanism featuring a translatable locking pin that provides strong and weak retention modes, a transparent cap for enhanced signal visibility, and customizable LED lights for improved readability and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the safety switch actuating mechanism is exposed to allow foreign objects to rest on it for testing or blocking purposes, then ease of operation is improved, but the switch becomes vulnerable to unauthorized blocking and malfunction

Engineering Contradiction:
Improveaccessibility for testingVSAvoidunauthorized blocking
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A protective cover encloses the actuating mechanism, providing physical protection while maintaining operational functionality. The cover can be designed with features such as transparent sections for visual inspection or controlled access points for authorized testing, thereby protecting against unauthorized blocking while allowing legitimate operation.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The protective cover acts as an intermediary barrier between foreign objects and the actuating mechanism. It allows authorized access for testing through controlled means (such as removable sections or transparent panels) while preventing unauthorized blocking by foreign objects, thus resolving the contradiction between accessibility and protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the safety switch is designed with enclosed housing to protect against foreign objects, then reliability is improved, but accessibility for maintenance and testing becomes difficult

Engineering Contradiction:
Improveprotection against foreign objectsVSAvoidaccessibility for maintenance
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The enclosed housing is segmented into removable panels or access doors that provide protected enclosures for internal components while allowing easy access for maintenance and testing. Critical components such as the actuating mechanism and contactless power transfer elements can be accessed through specific openings without compromising the overall protective enclosure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The housing incorporates transparent or translucent panels that maintain the enclosed protective structure while allowing visual inspection of internal components. This eliminates the need to open the housing for routine inspections, thereby maintaining reliability protection while improving ease of maintenance and testing.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP4352770B1Safety switch for guarding accesses
Publication Date: 2026.05.06 PIZZATO ELETTRICA SRL
  • EP4352770B1 patent drawingFigure 1
  • EP4352770B1 patent drawingFigure 2
  • EP4352770B1 patent drawingFigure 3

AI summary

A safety switch comprises a switching device (2) housing thereinside switching means, a driving device (3) adapted to interact with the switching means at the opening/closing of the access, wherein the switching device houses locking/releasing means (23) of the driving device (3) to prevent unauthorized opening of the access. The driving device (3) comprises an interaction element (17) adapted to fit into a slot (20) of the switching device (2) to interact with the locking/releasing means (23), these latter being provided with a locking pin (24) movable between an inoperative unlocking position and an operative locking position, the interaction element (17) being provided with a seat (25) for the insertion of one end of the locking pin (24). The locking/releasing means (23) comprises a locking element (40) adapted to translate to engage the interaction element (17) in a locking position wherein the interaction element (17) is locked on the switching device (2) and in a holding position wherein the interaction element (17) is removable.