Safety Switch Positive Driving Mechanism

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Solution Overview

Problem

Existing safety switches for electric machines are complex, prone to reliability issues due to the use of multiple parts and elastic elements, which can lead to jamming and rupture risks, and may fail to open the circuit properly in case of improper coupling or overload conditions.

Innovation Solution

A safety switch with a simplified construction using positive driving means without elastic elements, ensuring safe and reliable operation by directly checking the slider position and using a rigid motion transmission system to guarantee constant and effective opening of the power circuit, even in cases of disengagement or improper engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If elastic elements are used to actuate contacts in safety switches, then the contacts can be actuated mechanically, but the risk of jamming and rupture increases and reliability decreases

Engineering Contradiction:
Improvecontact actuationVSAvoidrisk of jamming and rupture
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent removes elastic elements entirely from the safety switch mechanism. Instead of using springs or elastic components to actuate contacts, the invention employs a direct mechanical linkage system where the push button directly drives the contact through a rigid connection, eliminating the source of jamming and rupture risks associated with elastic elements

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the elastic mechanical system with a rigid mechanical transmission system. A push button with a rigid stem directly drives a lever or linkage that opens the contact, substituting the elastic actuation mechanism with a more reliable rigid mechanical system that cannot jam or rupture

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

2Ease of operation

If multiple parts and elastic elements are used in safety switches, then contact actuation is achieved, but device complexity increases and reliability decreases

Engineering Contradiction:
Improvecontact actuationVSAvoidnumber of parts
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines multiple components into a simplified integrated structure. The push button, linkage, and contact assembly are merged into a compact unit where the button directly actuates the contact through a minimal linkage, reducing the number of separate parts while maintaining actuation functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent designs the push button mechanism to serve multiple functions simultaneously: it acts as the actuating force application point, the mechanical linkage element, and the direct driver of the contact opening mechanism, thereby reducing the need for separate dedicated components for each function

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Loss of information

If intermediate abutment members are used to indicate proper coupling, then coupling status is shown, but elastic elements are exposed to shocks and bending failure risk increases

Engineering Contradiction:
Improvecoupling indicationVSAvoidrisk of bending failure
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The patent removes intermediate abutment members and elastic indicators from the coupling indication mechanism. Instead, it uses a direct visual or mechanical indication method that does not rely on elastic elements subjected to shock and bending, such as a rigid positional indicator or direct mechanical interlock visibility

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If elastic elements are used for contact actuation, then contacts can be opened mechanically, but the switch may fail to open if contacts become welded due to overload

Engineering Contradiction:
Improvecircuit openingVSAvoidfailure to open welded contacts
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent incorporates a preliminary action mechanism where the rigid linkage system is designed to apply sufficient mechanical force to break welded contacts before the overload condition can sustain the weld. The mechanical advantage of the rigid linkage ensures that the opening force exceeds the welding force, preventing contact welding or breaking it if it occurs

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2141715B1Safety switch
Publication Date: 2015.04.08 PIZZATO ELETTRICA SRL
  • EP2141715B1 patent drawingFigure 1
  • EP2141715B1 patent drawingFigure 2
  • EP2141715B1 patent drawingFigure 3

AI summary

A push button safety switch comprising a box-like body (2) which houses therein at least one pair of stationary contacts (3, 4), a first slider (5) movable between two end positions (A, B), at least one pair of movable contacts (6, 7) operably connected to the first slider (5) to translate relative to the stationary contacts (3, 4) between the end positions (A, B), and to cause the circuit to open and close respectively, as well as a control push button (8) operably associated with the first slider (5) to cause it to slide within the box-like body (2), means for positive motion transmission (14) interposed between the push button (8) and the first slider (5) to cause positive opening of the circuit as the push button (8) is pressed, when the box-like body (2) is normally coupled to the push button (8), or as it accidentally disengages therefrom.