Safety Switch PCB Layout for Compact Guard Access Assembly

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Solution Overview

Problem

Existing safety switches for guarding accesses to industrial machines and plants are bulky, requiring complex wiring and multiple antennas, which complicates assembly and installation, and are not easily miniaturizable due to the inclusion of PCBs and components within the case and head, potentially interfering with access closure and increasing danger.

Innovation Solution

A safety switch design with a case and head configuration that allows the PCB to be split into two portions, one in each component, simplifying wiring and reducing the overall longitudinal size by aligning communication elements centrally, using a single antenna, and enabling compact assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the PCB and electronic components are housed entirely inside the case adjacent to the head, then the switching elements and circuits are protected and organized, but the overall longitudinal size of the safety switch increases to at least the sum of the PCB length and head length

Engineering Contradiction:
Improveprotection and organization of switching elements and circuitsVSAvoidoverall longitudinal size
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The PCB is divided into two separate portions: a first portion housed in the case and a second portion housed in the head. This segmentation allows each portion to be independently positioned, eliminating the need for the entire PCB to span the full longitudinal distance between case and head, thereby reducing the overall longitudinal size while maintaining functional integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The PCB portions are arranged in different spatial locations (case vs. head) rather than being linearly aligned end-to-end. This dimensional redistribution allows the communication elements to be centrally aligned and reduces the longitudinal footprint of the assembly.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If multiple antennas are provided to guarantee correct communication regardless of head position, then communication reliability is improved, but the device becomes bulkier and more difficult to install

Engineering Contradiction:
Improvecommunication reliabilityVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

A single antenna is positioned centrally in the head rather than distributing multiple antennas across different locations. This asymmetric, centralized positioning ensures that the antenna remains optimally positioned for communication regardless of the head's rotational orientation, eliminating the need for multiple antennas while reducing device volume.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The single centrally-positioned antenna serves all communication functions regardless of head orientation or position. This universal positioning allows one antenna to replace what would otherwise require multiple antennas oriented in different directions, reducing the overall device size while maintaining communication reliability.

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

3Length of moving object

If the safety switch has a reduced longitudinal size, then interference with access closure is minimized, but the PCB and components become more difficult to arrange and wire

Engineering Contradiction:
Improvelongitudinal sizeVSAvoidarrangement and wiring of PCB and components
Core Design Contradiction:
Length of moving objectVSEase of manufacture

Solution Approach 1:

The PCB is segmented into two portions that can be independently arranged in their respective locations (case and head). This segmentation simplifies the wiring process by allowing each portion to be connected to nearby components locally, rather than requiring long wiring runs across the entire assembly, thus easing manufacture despite the compact size.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The segmented PCB portions act as intermediaries between the switching elements in the case and the communication elements in the head. This arrangement allows for simplified local connections at each end while maintaining the functional link between components, making assembly easier in the compact configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4451305B1Safety switch for guarding accesses to machines or industrial plants and related assembly
Publication Date: 2025.08.27 PIZZATO ELETTRICA SRL
  • EP4451305B1 patent drawingFigure 1~2
  • EP4451305B1 patent drawingFigure 3
  • EP4451305B1 patent drawingFigure 4~5

AI summary

A safety switch for guarding accesses to industrial machines or plants comprises a case (4) which extends along a main dimension defining a longitudinal axis of development (L), control means housed in the case (4) and suitable for receiving and exchanging signals with the actuating device (2) and/or with the machine or plant and provide with a first PCB (31), a head (9) connected to the case (4) and adapted to interact with the actuating device (2) upon the opening/closing of the access and wherein the first PCB (31) comprises a first longitudinal portion housed in the case (4) and a second longitudinal portion housed in the head (9).